Philippine Normal University – Center for Teaching and Learning
CHAPTER I
INTRODUCTION
There were many useful plants abundantly growing here in the Philippines. Most of
them were herbal plants that could cure severe diseases such as cancer and other related
sicknesses. Others are considered as useful plants by farmers because of their varied uses in
the farm. One of them was Madre de Cacao or locally known as kakawate but scientifically
known as Gliricidia sepium. This plant was a nitrogen–fixing tree. In some areas, it was
referred to as a quick–stick due to its characteristic of growing almost right away just by
cutting it and directly planting it in the ground. It was also rumored to be a potential insectrepellant and the researcher wanted to examine this assertion.
Pest control had always been a major problem in most of the corner of every house,
farm, backyard, and even out in the open areas. Disease-carrying insects were the ones
most especially needed to be eliminated. This phenomenon led to the production of such
pesticides and insecticides to protect the people, animals, and plants from harmful effects
that pests and insects can cause.
Insecticides were any toxic substances that were used to kill insects; but in some
cases, they were also poisonous to people and caused several kinds of diseases including
cancer and allergy. Such substances were used primarily to control pests that infested
cultivated plants or to eliminate disease-carrying insects in specific areas. Most insecticides
1
Philippine Normal University – Center for Teaching and Learning
were sprayed or dusted onto plants and other surfaces traversed or fed upon by insects. The
early production of pesticides was made with the aid of hazardous chemicals that could
also harm the health of each and every on of us. It was not advisable to use because of its
harmful effects to humans. Hence, there have been several studies to establish a substitute
to these hazardous insect–repellants. The researcher replicated the same pest control
activity using the extracts from the kakawate leaves, or scientifically known as Gliricidia
sepium.
1.1 Background of the Study
The Philippines is endowed with a rich supply of flora from both land and sea.
There are more than 8,000 species of plants and several of these have pesticidal properties.
The study of the utilization of the toxic substances produced by plants in our environment
to control pests has gained recognition in the previous years and this is a positive approach
in meeting the current worldwide economic crisis problem. The natural product of plants
has been tapped to provide a vast source of toxic substances that may be utilized in the
control of pests. (Ambros, l991)
Gliricidia sepium, locally known as madre de cacao or kakawate, is identified as
one of the potential sources of organic fertilizer since it is a leguminous and fast growing
nitrogen-fixing tree. It is adaptive to a wide range of agroclimatic conditions and produces
many branches that give enough foliage for green manuring and feed purposes. (Juanita
Coraza, March 2000)
2
Philippine Normal University – Center for Teaching and Learning
For a hundred of years, botanists all over the world discovered that plants could be
used as a healing herb, pesticide, insecticide and an insect-repellant. Examples of these
plants are:
Makabuhay (pesticide), Derris roots (insecticide), aromatic herbs (insect
repellant), and others. (Crisologo Ramasasa, Article base)
Worms, bugs and other rice pests are an enigma to many farmers as these are
threats to rice production. And to most farmers, commercial insecticides and pesticides are
the most effective and readily available pest controls. What they do not realize is that these
cost them added expenses not to mention the bad effects of these chemicals to health and
environment. (Agriculture Business Week, 2010)
The early production of pesticides is made with the aid of hazardous materials that
can also harm the health of each and every one of us. It is not advisable to use because of
its harmful effects too. There have been several studies to establish a substitute to these
hazardous insect-repellants. Dr. Alfredo R. Rabena, Head of the Research and
Development Office of the University of Northern Philippines in Vigan City, Ilocos Sur,
discovered a solution. He found that the leaves of the kakawate tree of Mexican Lilac
(Gliricidia sepium) contain coumarins, an effective botanopesticide. (Agriculture Business
Week, 2010)
3
Philippine Normal University – Center for Teaching and Learning
The popular use of madre cacao leaves as a repellant to rice case worms by farmers
in the locality promoted the research of Fidelismo Beltran in evaluating this plant specie for
possible use as pesticide to control sweet potato weevil.
(Fidelismo Beltran, May l990)
A research study was made by Ligaya Cintura, Chona Joy Lumabao, and Domingo
Diaz on kakawate or madre cacao as an organic pesticide on diamond moth. Results
revealed that the organic pesticide significantly affected the control and treatment of the
insects. (Cintura, 2011).
Common housewives experience a difficulty of eradicating these pests due to the
rising cost of commercial insecticides which they could hardly afford. This was even
coupled by the problem of commercial insecticide leaving toxic residues on food, water
and atmosphere which pose danger to the consuming public. Thus, it becomes imperative
to explore and develop alternative control measures for reason of costs, availability,
environmental pollution and hazards to human and animal health brought about by
pesticide and insecticide use. (Davidson & Lyon, l979)
It was for this reason that the researcher has decided to conduct an experiment on
the use of plant resources, which is kakawate, with known toxic properties which are
abundant in the locality using cockroach as a controlled variable.
1.2 Objectives of the Study
4
Philippine Normal University – Center for Teaching and Learning
The study entitled “Gliricidia Sepium as an Insecticide” has the general objective of
coming up with an alternative insecticide that is cheaper, organic, effective for
cockroaches. As found out by Dr. Alfredo R. Rabena, Head of the Research and
Development Office of the University of Northern Philippines in Vigan City, Ilocos Sur,
the leaves of the kakawate tree of Mexican Lilac (Gliricidia sepium) contain coumarins, an
effective botanopesticide. This idea was the basis of this study and experimentation.
The researcher had the following specific objectives:
1.To be able to extract the kakawate leaves to produce cheaper and organic insecticide.
2.To determine the chemical compound present in the kakawate leaves that can harm pests
and therefore making it a potential insecticide.
3.To test the efficiency of this organic insecticide through sample application with
cockroaches.
4.To determine the appropriate concentration of the leaves extract to produce an effective
organic insecticide.
5.To see if some people would like this idea of kakawate leaves as an insecticide through
the survey questionnaires.
Household today are plagued with the perennial problems of house pests, one of
which is cockroach. Cockroaches have been around for million of years. They outlived
the dinosaur, survived disasters and still continue to pester man to this day. They sneak
around anywhere from sewers to tables, feasting greedily on wastes and foods. As a result,
5
Philippine Normal University – Center for Teaching and Learning
they transmit germs that can cause food poisoning, infections and diarrhea. (Manila
Bulletin, l991)
Many species of cockroaches are found throughout the world. Some infest the
households and they are frequently found in restaurants, hotels, hospitals, and groceries.
Their presence is so objectionable that they are considered among the worst of domestic
pests. (Davidson and Lyon, l979)
The relevance of this research lies on its possible solution of getting rid of house
pests like the cockroaches through the production of an insecticide which is locally made,
involves lesser cost and readily available in the surroundings. (Ambros, 1991)
The use of kakawate as insecticide may bring comfort and good health within the
household. If pests like cockroach are not controlled, they infect the foods and grains in
the house. (Ross, l965)
This study hoped to contribute to the upliftment of the present economic status,
which our country is experiencing nowadays due to global oil crisis and natural calamities.
This study showed the advantages of using a specified plant (kakawate) over the
commercial insecticide because of the availability of such plant in the community, its ease
in processing whereby housewives will not have a difficulty in adding chemical to extract
the leaves and it does not pose hazard to environmental pollution that is detrimental to
human health. (Ambros, l991)
6
Philippine Normal University – Center for Teaching and Learning
This study served as further encouragement for more scientific research in the
utilization of our plant resources leading to national progress by way of reducing
importation of insecticide and preserving the environment. (Ambros, l991)
1.3 Scope and Delimitation
There have been several studies proving the helpful benefits of Gliricidia sepium,
locally known as kakawate, as pesticide. Research has also been conducted on both the
antifungal and antimicrobial properties of Gliricidia sepium extracts.
However, the
researcher focused on proving the potential of kakawate as an organic insecticide.
The study would also prefer insects to be experimented on, specifically
cockroaches, rather than pests like rats because kakawate was already proven as a
pesticide.
The researcher made the experiment at home. The materials needed were beakers,
strain cloth, graduated cylinder, basin, Erlenmeyer flask, mortar and pestle, weighing scale,
water, ethanol (70%) and kakawate leaves. If someone wants to further simplify the
procedure, a simple strain cloth and container would be enough.
The researcher was only restricted in using a commercialized material, 70% ethyl
alcohol or ethanol, for the digestion of the kakawate leaves. Once the leaves were
7
Philippine Normal University – Center for Teaching and Learning
extracted, it would be placed in a sprayer and would be tested to kill cockroaches. In using
the ethanol, different variation of volume of it was used in constant amount of leaves to
identify which volume of the alcohol could yield the most effective insecticide. Why use
alcohol? All tannins have several common properties amongst them. While the tannins are
soluble in water and alcohol, they do not dissolve in organic solutions.
Again, when
reacted with nitrogeneous bases, polysaccharides, some alkaloids, few glycosides and
proteins, all tannins form precipitates. (http:www.herbs2000.com/h_menu/tannins.htm)
The kakawate extract was only tested to cockroaches, and the extract was made by
following only the given procedure. No additional chemicals to inhibit or to affect the
efficiency of the said insecticide were added. The researcher saw the effectiveness of the
kakawate leaves in killing the cockroaches.
The researcher developed a questionnaire that consisted of 5 questions for 30
women respondents with the age of 19 years old and above because “common housewives
experience a difficulty of eradicating these pests due to the rising cost of commercial
insecticides which they could hardly afford.”(Ambros, 1991)
1.4 Conceptual Framework
The experiment begun with the gathering of kakawate leaves that were free from
diseases. The ground kakawate leaves were saturated in the beaker for five hours with 70%
ethanol to form the proposed organic insecticide which the researcher hoped would be used
8
Philippine Normal University – Center for Teaching and Learning
to kill the controlled variable: cockroach. The extracts or filtrates were placed in a sprayer.
. Each cockroach was sprayed 20 times with the resulting solutions. (See the solution
combinations in the given table). The time duration of the death of the cockroach was
observed and noted.
Conceptual
Framework
1.
2.
GRINDING
SOAKING
(5 hours)
3.
4.
FILTERING
MIXING
Grind 100 gm. of kakawate leaves
Soak the ground leaves of kakawate leaves
in the given volume of ethanol (70% conc.)
1st trial = 150 ml
2nd trial = 160 ml
3rd trial = 170 ml
4th trial = 180 ml
5th trial = 190 ml
Use strain cloth
Mix 100 ml of filtrate with
100 ml of water
5.
SPRAYING
Spray mixture to cockroach
(5 trials using different
volumes
of soaking substances)
See above
9
Philippine Normal University – Center for Teaching and Learning
6.
OBSERVING
Note the elapsed time before
the cockroach expired
(on each of the indicated trial
volume of ethanol)
7.
INTERPRETATION
Note: The respondents were given the extract with most potent solution (150 ml ethanol)
and they did the experiments themselves. (spraying and observing)
1.5 Definition of Terms
a. Kakawate – (Kakawate DOST)
Common names: Kakawate, Madriado, Madre de cacao
Scientific name:Gliricidia sepium
Family: Leguminosae
Kakawate is a nitrogen-fixing tree. In some areas, it is referred to as a quickstick due to its characteristic of growing almost right away just by cutting it and
planting it in the ground. It is a fast growing tree with a maturity height of 10
meters (33 feet). It is adaptable to almost any soil environment, including
infertile soils. It is tolerant to salt spray and water logging. It can tolerate
drought for up to 6 to 8 months. This tree can be potentially weedy, but rarely
causes a problem. Its ubiquitous characteristic makes it a good alternative for
feeds due to its availability in almost all areas in the country.
10
11
Philippine Normal University – Center for Teaching and Learning
b. insecticide - any substance used to kill insects (New World Dictionary)
c. pesticide - an agent used to destroy pests (The Merriam-Webster Dictionary)
d. insect-repellant
-
a
chemical
substance
that
repels
insects
(http://www.thefreedictionary.com/insect+repellant)
e. cockroach - any of an order (Blattaria) of insects with long feelers, and a flat
soft body; some species are common household pests (New World Dictionary)
f. toxic - poison (The Merriam-Webster Dictionary)
g. pest - any destructive or troublesome insect, small animal, weed, etc. (Webster
New World Dictionary)
h. effectiveness - efficiency (Webster New World Dictionary)
i. respondents - persons who respond or answer (Webster New World Dictionary)
j. flora - plants or plant life especially of a region or period (The MerriamWebster Dictionary)
k. coumarin - a chemical that came from tonka beans; a white, crystalline
substance, with the odor of vanilla, obtained from the tonka bean and certain
plants or made synthetically (Webster New World Dictionary)
l. tannins – a yellowish, astringent substance, derived from oak bark, gallnuts, etc
and used in tanning medicine (Webster New World Dictionary)
m. botanical pesticide - Pesticides whose active ingredients are plant-produced
chemicals such as nicotine, rotenone, or strychnine. Also called plant-derived
pesticides. Being "natural" pesticides, as distinct from synthetic ones, they are
Philippine Normal University – Center for Teaching and Learning
typically acceptable to organic farmers.
(http://www.termwiki.com/EN:botanical_pesticides)
12
Philippine Normal University – Center for Teaching and Learning
CHAPTER II
REVIEW OF RELATED LITERATURE AND STUDIES
The researcher had gathered related literature in Agriculture Business Week, article
from the Manila Bulletin, texts by Davidson, Lyon and Ross. Related studies by Dr.
Alfredo Rabena and Francisca Aquino-Ambros were also gathered and related studies on
natural insecticides.
2.1Review of Related Literature -
Agriculture Business Week (Kakawate Leaf: An effective Pesticide)
Worms, bugs and other rice pests are an enigma to many farmers as these are
threats to rice production. To most farmers, commercial insecticides and pesticides are the
most effective and readily available pest controls. What they don’t realize is that these cost
them added expenses not to mention the bad effects of these chemicals to health and
environment.
Dr. Alfredo R. Rabena, head of the Research and Development Office of the
University of Northern Philippines in Vigan City, Ilocos Sur, has discovered a solution. He
found that the leaves of kakawate tree or Mexican Lilac (Gliricidia Sepium) contain
coumarin, an effective botanical pesticide. To prepare the solution, chop the kakawate
leaves and let these soak overnight to extract coumarin. Using a strainer, separate the
leaves from the solution.
13
Philippine Normal University – Center for Teaching and Learning
Spray the solution to the rice fields. The best time to apply it is from eight o’clock
to nine o’clock in the morning and from five o’clock to six o’clock in the afternoon as
worms and pests are coming out from the leaves at these times. So the solution would be
more effective to use. If applied early, it would not be that effective as pests are still
hibernating. And if used when the sun’s heat is too hot, it would not be that effective also
as pest would hide.
Since kakawate is a legume, says Rabena, its leaves are rich in nitrogen, an
important soil nutrient. Hence, the discarded leaves can be applied to the field as an
organic fertilizer. He also recommends farmers to put several leafy branches of kakawate
tree in between rice plants two days after planting to prevent pests from attacking the crop.
To prove this research finding, Rabena and Flora Cely Rodilis did a demonstration
in Naglaoa-an, Sto. Domingo, Ilocos Sur as well as in Vigan City and Lidlidda, Ilocos Sur
where the kakawate leaves botano-pesticide effectively eliminated rice weevils, rice bugs,
and worms in rice fields. To make the chopping of leaves easier, Rabena and Dr. Manuel
Bajet Jr. designed a chopper. Called Dual Operated Foliage Chopper, the device can either
be operated electrically or manually as it has a pedal. It costs P21,000 and there are units at
the University.
Article From Manila Bulletin “House Pests”, 1991
Household today are plagued with the perennial problems of house pests, one of
which is the cockroach. Cockroaches have been around for millions of years. They
outlived the dinosaur, survived disasters and still continue to pester man to this day. They
sneak around anywhere from sewers to tables, feasting greedily on wastes and foods. As a
14
Philippine Normal University – Center for Teaching and Learning
result, they transmit germs that can cause food poisoning, infections and diarrhea. (Manila
Bulletin, l991)
“Insect Pests, 1979”
Many species of cockroaches are found throughout the world. Some infest the
households and they are frequently found in restaurants, hotels, hospitals, groceries. Their
presence is objectionable that they are considered among the worst of domestic pests.
(Davidson and Lyon, l979)
“A Textbook of Entomology”
If pests like cockroaches are not controlled, they infect the food and grains in the
house. The presence of cockroach is a sign of unclean condition. So there is a need to
control these insects and these control measures are justifiable in terms of comfort and
economy. (Ross, l965)
“Tannins”
Tannins are polyphenols that are obtained from various parts of different plants
belonging to multiple species. Deriving it name from the technical word ‘tanning’ that
meant converting animal hides to leather through chemical processes; tannin is basically
used for this function. It is found in abundance in the tree bark, wood, fruit, fruit pod,
leaves, and roots and also in plant gall. Since earlier times, people obtained tannin for
tanning from plants like wattle (Acacia sp.), oak (Quercus sp.), eucalyptus (Eucalyptus
15
Philippine Normal University – Center for Teaching and Learning
sp.), birch (Betula sp.), willow (Salix caprea), pine (Pinus sp.), quebracho (Scinopsis
balansae).
Tannins are found as shapeless yellowish or light brown masses like powder, flakes
or sponge. Interestingly, tannins are found almost in all plants and in all climates all over
the world. Although algae, fungi and mosses do not contain much tannin. The percentage
of tannins present in the plants, however, varies. While they are present in significant
proportions in some plants, many others have too little of them. Tannins are usually found
in large quantities in the bark of trees where they act as a barrier for micro-organisms
like bacteria and fungi and protect the tree. Apart from tanning, tannins are also used in
dyeing, photography, refining beer and wine as well as an astringent in medicines.
Significantly, tannins form a vital element of tea!
Tannins can be classified into two broad groups - hydrolysable tannins and
condensed tannins.
Hydrolysable tannins are basically derived from simple phenolic acids like gallic
acid or ellagic acid and when heated they give away pyrogallol. Pyrogallol is also known as
hepatotoxic and has antiseptic as well as caustic properties. Owing to the hepatotoxic
property, plants that have a concentration of tannins are not appropriate for application on
openwounds. When out in the open air hydrolysable tannins normally change to a brownish
color and are accountable for the brown color of many plant dyes.
On the other hand, condensed tannins, also known as non-hydrolysable tannins, do
not split easily and hence it is difficult to analyze these. Condensed tannins are
16
Philippine Normal University – Center for Teaching and Learning
basically flavonoid dyes formed through bio-synthesis of flavins and catechins. When these
non-hydrolysable tannins are heated up in acids they synthesize to yield a red insoluble
substance known as tannin reds or phlobaphenes. Phlobaphenes are flushed precipitates
found in some plants that have reddish tints and this is an indication that these plants have
rich concentration of condensed tannins. When condensed tannins are heated, catechol
emerges as the final product. Unlike hydrolysable tannins, condensed tannins do not
possess any trace of hepatotoxicity or any adverse side effects and hence are favorable for
use.
In addition to hydrolysable and condensed tannins, other examples of polyphenols
include arbutin derived from uva ursi (Arctostaphylos uva-ursi), rugosin-D obtained
from meadowsweet (Filipendula ulmaria) and sanguin H-6 from raspberry leaves (Rubus
idaeus).
Interestingly, all tannins have several common properties amongst them. While the
tannins are soluble in water and alcohol, they do not dissolve in organic solutions. Again,
when reacted with nitrogenous bases,polysaccharides, some alkaloids, few glycosides and
proteins all tannins form precipitates. Medically, tannins are used as antidotes to poisoning
by alkaloids depending on their capacity to form insoluble tannates. However, only dilute
solutions of tannins are applied for this work. Finally, almost all tannins consumed remain
exuded during the digestive process, and different quantities of it enter the body fluids and
are emitted by the kidney.
17
Philippine Normal University – Center for Teaching and Learning
The above-mentioned properties of tannins should always be kept in mind while
applying extracts from tannin-rich plants for medicinal purpose. Tannin is basically an
astringent that means that it tauten the pores and pulls out liquids from plants. In plants,
tannins are large astringents molecules that easily attaches with proteins. To find the truth
about these properties of tannins you may try a few small experiments. If you put tannin on
your skin, you will witness it to shrink and if you apply if on your face you will
notice wrinkles appearing. At the same time, tannins help to draw out all irritants from the
skin. These properties impart medicinal qualities to tannin which is applied on the skin to
pull out poisons from bee stings or poison oak bringing in instant relief.
The other remedial values of tannins include application on burns to heal the injury
and on cuts to stop bleeding. Tannin’s ability to form a strong ‘leather’ resistance on the
exposed tissues helps in protecting the wounds from being affected further. While it
stopsinfection from above, internally tannin continues to heal the wound. In case of third
degree burns using strong tannin sources will not only prevent septicemia, but also help to
save life. This traditional method has been practiced by most medicos in all countries. On
the other hand, when a tannin-rich solution is poured on the flesh, it generates a sealing
'eschar' that often helps in growing new skin albeit temporarily. This technique requires
repeated washing of the wound with tannins and this helps to eliminate the bacteria too.
Hence, tannins are also said to have antiseptic properties. Interestingly, this practice is still
followed in the primary health care centers in China and is also recommended as a first-aid
treatment at places where emergency medical services are still inadequate or faulty.
18
Philippine Normal University – Center for Teaching and Learning
Tannins can also be effective in curbing hemorrhages as well as restrict bare
swellings. While tannins are proved haemostatics, they are also beneficial when applied on
mucosal coating in mouth. Hence, herbs possessing tannins are widely used as
mouthwashes, eyewashes, snuff and even as vaginal douches and also treat rectal disorders.
When applied internally, tannins affect the walls of the stomach and other digestive parts.
They sour the mucus secretions and contract or squeeze the membranes in such a manner
that secretions from the cells are restricted. The good thing is that tannins’ antiinflammatory effect helps to control or curb all indications of gastritis, enteritis,
eosophagitis and irritating bowel disorders. This action is possible by involving lymph
stasis and neutralizing the autolytic enzymes. Conventionally, tannins have also been used
to cure diarrhea. In most rural areas diarrhea is caused due to the irritation of the enteritis or
the small intestine and is the reason for many deaths worldwide. Although diarrhea initially
affects the large bowel, but a reflex action origination higher up aims at eliminating the
disturbing material in the system as early as possible. Diarrhea many be considered to be a
healthy action as it helps to remove the unwanted or disturbing substance from the system,
but if it prolongs, it may lead to dehydration and nauseaoften resulting to death. Thus, in
order to control the fierceness of diarrhea, application of an effective astringent medicine is
recommended. An effective astringent does not stop the flow of the disturbing substance in
the stomach, but helps in controlling the irritation in the small intestine.
In earlier days, bowel looseness was a result of infection in the small bowel. But in the
contemporary society, there are other reasons than this for the disorder. Today looseness of
bowel can occur even due to bowel tremor and worsening irritating diseases in the small or
19
Philippine Normal University – Center for Teaching and Learning
large bowel. This means that the application of tannins is restricted in bowel disorder cases
these days. However, they can still be used to reduce irritations and control the ferocity of
diarrhea. These days agents such as kaolin and morphine are also used to treat the
looseness of bowel. Tannins, however, differ from them as they are purely applied on the
basis of symptoms and have a healing effect on the bowel wall. At the same time, tannins
restraint the entry of any unwanted pathogenic substances.
Although tannins are beneficial in treating bowel irritations and many other ailments, there
is a need to restrict or limit the wanton use of tannins in order to avoid unwanted problems.
It is a well-known fact that when reacted with all proteins (including dietary proteins)
tannins form precipitates. But these tannin-proteins are too complex to be soaked into the
blood stream and while they are in the digestive system they intend to restrict or retard the
secretion of enzymes. Hence, it is important to restrict the usage of the medicines rich in
tannins. This is particularly important when consuming tea and coffee without milk. As the
astringent in these beverages retard the metabolism process, it is always advised that tea
and coffee should be taken only lightly brewed. And it is even better to consume tea with
milk or lemon juice that counteracts the effects of astringent.
(Tannins(n.d.) Retrieved Feb 2nd, 2012., from herbs 2000. http://www.herbs2000.com/h
menu/tannins.htm)
“What is an Astringent?”
20
Philippine Normal University – Center for Teaching and Learning
An astringent is a substance which causes biological tissue to contract or draw
together. There are a number of uses for astringents medically, and many cosmetic
companies also sell astringents for skin care. The term is also used to refer to tart foods
which
cause
the
mouth
to
pucker,
such
as
lemons,
pomegranates,
and persimmons. Tannins, such as those found in teas and wines, are also astringents, since
they cause the mouth to feel dry and constricted. Many of these tannins, such as oak bark,
are used to produce astringent products for both medical and cosmetic use.
The word's origins can be found in the Latin astringere, which means “to bind
fast.” An astringent can be said to have “astringency” when someone is describing its
properties. When an astringent is applied to living tissue, it does indeed cause the tissue to
bind fast to itself, causing it to shrink. This property can be extremely useful for a variety
of applications.
In internal medicine, astringents are used to shrink mucus membranes. By reducing
swelling, a doctor can identify areas of bleeding or irritation more readily. The use of a
medical astringent can also act to reduce unwanted discharge, which will make patients
more comfortable. Many doctors also prescribe astringents to relieve skin irritations such
as those cause by fungal infection and insect bites. Calamine lotion is an example of a
topical medical astringent designed to reduce irritation, as is witch hazel. Pet guardians
may have used stronger astringents, in the form of styptic pencils or sticks, which are
designed to be applied to nails which have been cut too short in order to stop the bleeding.
21
Philippine Normal University – Center for Teaching and Learning
In cosmetics, astringents are used to firm and tone the skin, constricting
the pores and creating a protective layer of firm tissue between the under layers of skin and
the elements. A cosmetic astringent is sometimes called a toner, and it is usually applied
after bathing but before the application of moisturizers. Aftershaves are also astringents.
Using an astringent after shaving can help to reduce the pain of minor cuts while also
soothing the skin.
Applying excessive astringents, especially harsh ones such as alcohol, can be
drying. This is why many cosmetic astringents are followed by moisturizer, to keep the
skin moist as well as firm. There is also some debate in the medical community over
whether or not people with acne should use astringents. Some people argue that the
astringents may have a positive impact, while others fear that astringents restrict the pores,
leading to an increased likelihood of blockage and infection.
(Smith S.E. (n.d.) What is an Astringent? Retrieved Feb 2nd, 2012, from wisegeek.
http://www.wisegeek.com/what-is-an-astringent.htm)
2.2Related Studies -
Thesis on “The Isolation, Characterization and Identification of Active Botano Chemicals
of Kakawate Leaves Against Termites”, Dr. Alfredo R. Rabena
Dr. Alfredo R. Rabena presented this finding through his paper “The Isolation,
Characterization and Identification of Active Botano Chemicals of Kakawate Leaves
against Termites” that he presented during the 5th Intenational Congress of Plant Molecular
Biology in Singapore in l997. His study was also included in the book “The International
22
Philippine Normal University – Center for Teaching and Learning
Society for Plant Molecular Biology” published by the National University of Singapore
and Institute of Molecular Agrobiology.
Coumarins in kakawate leaves are also effective termites-and-bed bugs neutralizer.
Kakawate leaves are also effective anti-fungus. It can cure Trichophyton metagrophytes
that causes skin disease like eczema. Crumple several leaves and apply to affected area of
the skin for a salicylic acid-like effect.
Dr. Rabena and Dr. Nelia Aman, and Engr. Franklin Amistad have discovered that
the ash of kakawate can be a good concrete mixture for ceramics. Its charcoal is a good
moisture and odor absorbent, too. Kakawate leaves can be used also to de-worm pigs. Just
have the swine eat ample leaves and the parasites will not live long. If these uses are not
enough, then remember that kakawate’s flowers can be made into salad or into dinengdeng,
a delicious Ilokano veggie dish.
Thesis on “Effectiveness of Nerium Indicum as Insecticide to House Pests Blatta Orientalis
(Cockroaches), Francisca Aquino-Ambros, May 1991
The Philippines is endowed with a rich supply of flora both land and sea. There are
more than 8,000 species of plants and several of these have pesticidal properties.
The study of the utilization of the toxic substances by plants in our environment to
control pests has gained recognition in the previous years and this is a positive approach in
meeting the current worldwide economic crisis problem. The natural product of plants has
been tapped to provide a vast source of toxic substances that may be utilized in the control
of pests.
23
Philippine Normal University – Center for Teaching and Learning
Common housewives experience a difficulty of eradicating these pests due to the
rising cost of commercial insecticides which they could hardly afford.
This is even
coupled by the problems of commercial insecticide leaving toxic residues on food, water
and atmosphere which pose danger to the consuming public. Thus, it becomes imperative
to explore and develop alternative control measures for reason of costs, availability,
environmental pollution and hazards to human and animals’ health brought about by
pesticide use. It is for this reason that the researcher decided to conduct an experiment on
the use of plant resources with known toxic properties which are abundant in the locality to
answer the needs of the Filipinos for effective pest control. The relevance of this research
lies on its possible solution of getting rid of house pests like the cockroaches through the
production of an insecticide which is locally made, involves lesser cost and readily
available in the surroundings.
This study hoped to contribute to the upliftment of the present economic status,
which our country is experiencing nowadays due to global oil crisis and natural calamities.
This study will show the advantages of using a specified plant over the commercial
insecticide because of the availability of such plant in the community, its ease in processing
whereby housewives will not have a difficulty in adding chemical to extract the flower and
it does not pose hazard to environmental pollution that is detrimental to human health.
This study will also serve as further encouragement for more scientific research on the
utilization of our own plant resources leading to national progress by way of reducing of
importation of insecticide and preserving the environment.
24
Philippine Normal University – Center for Teaching and Learning
Thesis – “Effects of Soil Incorporation of Madre de Cacao Leaves on Sweet Potato Weevil
Manifestation, Growth and Yield of Sweet Potato”, Fidelismo Beltran, l990
Recently, the increasing costs of pesticides and the growing concern of the general
public about increasing environmental pollution as a result of continued pesticide use
enhanced the interest of researchers to discover and develop other means for the control of
sweet potato weevil.
Exploring locally available materials such as plant parts could be a possible
alternative as wide-ranged pesticides. The popular use of madre de cacao leaves as
repellant to rice case worms by farmers in the locality promoted the researcher (Mr.
Beltran) to experimentally evaluate this plant specie for possible use as pesticide to control
sweet potato weevil.
2.3 Related Studies on Natural Insecticides
Since 1690, extracts from tobacco have been used as insecticides. As early as 1927,
researches on natural insecticides from plants have been conducted in the Philippines
utilizing fresh and dried tobacco leaves as insecticide. (Ogot, l989)
In the rural area of Thailand, the people like to use extracted nut from stemma
specie for the control of animal and human pests such as lice, flee, etc. (Sombatsiri &
Pathumachartpat, l979
Carino (196l)… screened nine composite species for insecticide.
25
Philippine Normal University – Center for Teaching and Learning
Summary of Review of Related Literature and Studies
For these past few years botanist all over the world have been finding a solution for
a cheaper and safer insecticide. Many have found potential plants as can be seen in these
related literature and studies. One is Dr. Alfredo Rabena who found that the leaves of
kakawate tree contain coumarin, an effective botanopesticide and also effective termitesand-bed bugs neutralizer. Kakawate leaves are also anti-fungus and can be used to deworm pigs, and its ashes can be a good concrete mixture for ceramics. Francisca AquinoAmbros also studied the effectiveness of nerium indicum as insecticide to cockroaches.
The literature and studies pointed to the need of getting rid of house pests like
cockroaches through the production of insecticide with known toxic properties and which
are abundant in the locality – the kakawate.
26
Philippine Normal University – Center for Teaching and Learning
CHAPTER III
METHODOLOGY
Standard procedures for the preparation and the application of the plant extracts were
presented here in Methodology. The kakawate leaves were gathered. Those with sign of
infestation on the leaves were rejected and the only leaves with healthy dark green color
were the ones collected and would be used as raw materials. The method was extraction
and variation of volume of ethanol in killing the cockroaches.
3.1 Standard Procedures for the preparation and application of the plant extracts
1.Select plant leaves that are free from diseases.
2.When storing the plant parts for future usage, make sure that they are properly dried and
are stored in an airy container, away from direct sunlight and moisture. Make sure that
they are free from molds before using them.
3.Use utensils for the extract preparation that are not used for your food preparation and for
drinking and cooking water containers. Clean properly all the utensils every time after
using them.
4.Do not have a direct contact with the crude extract while in the process of the preparation
and during the application.
5.Make sure that you place the plant extract out of reach of children and house pets while
leaving it overnight.
27
Philippine Normal University – Center for Teaching and Learning
6.Wear protective clothing while applying the plant extract.
7.Wash your hands after handling the plant extract.
3.1.1 Procedure for the making of kakawate extracts
1.Kakawate leaves that were healthy and free from disease were gathered.
2.Kakawate leaves were ground using mortar and pestle.
3.Weighed 100 grams of the ground kakawate leaves.
4.Measured 150 ml of 70% ethanol in a beaker.
5.Soaked the ground kakawate leaves on the beaker for five hours. Sealed the beaker with
aluminum foil to avoid evaporation of the ethanol.
6.Filtered the solution with the strain cloth after soaking for five hours.
7.Measured 100 ml of the extract in an Erlenmeyer’s flask with 100 ml of water from a
graduated cylinder.
8.The resulting filtrate, kakawate + ethanol, served as the insecticide. Sprayed it on a live
cockroach and observed what happened. Noted the time of death of the cockroach.
9.Repeated the procedure using 160, 170, 180 and 190 ml of 70% ethanol.
3.1.2 Materials and Instruments
Kakawate leaves
strain cloth
mortar and pestle
sprayer
5 live cockroaches
250 ml beakers
28
Philippine Normal University – Center for Teaching and Learning
70% ethanol
weighing scale
basin
graduated cylinder
Erlenmeyer’s flask
water
3.2 Analysis
The researcher analyzed the effect or efficiency of the variation of volume of
ethanol in killing the cockroach. The volume of the ethanol that was used for each trial
started at 150 ml and was increased incrementally by 10 ml until the 190 ml limit was
reached. The most efficient amount of soaking solution for the ground kakawate leaves is
150 ml.
3.2.1 Data Interpretation and Calculations (Variation of Volume of Alcohol)
Table 3.1
Cockroach
Volume of the ethanol
(ml) added to 100 gm
of kakawate
Volume of the extract
(ml) added to 100 ml
of water
No. of Sprays
1st
150
100
20
2nd
160
100
20
3rd
170
100
20
4th
180
100
20
5th
190
100
20
29
Philippine Normal University – Center for Teaching and Learning
Column one on the table represented the 5 live cockroaches that were sprayed with
the extracted kakawate. (that was, one cockroach per trial)
Column two represented the
different volume of ethanol (70% concentration) added to 100 ml of ground kakawate.
This volume of ethanol started with 150 ml and would increase by 10 ml (for each
procedure) until it would reach 190 ml. Column three described the volume of the extract
which was constant at 100 ml. This amount of extract was combined with 100 ml of water
(for each trial). Column four was the number of sprays (20 sprays) employed in killing the
cockroach.
30
Philippine Normal University – Center for Teaching and Learning
CHAPTER 1V
RESULTS AND DISCUSSION
4.1 Interpretation of the results of the experiment
Table 4.1
Experiment Results
Cockroach
Volume of the
ethanol (ml)
added to 100 gm
of kakawate
Volume of the
extract (ml)
added to 100 ml
of water
No. of Sprays
Length of time before
death (min.)
1st
150
100
20
8.0
2nd
160
100
20
15.0
3rd
170
100
20
24.0
4th
180
100
20
33.0
5th
190
100
20
45.0
31
32
Philippine Normal University – Center for Teaching and Learning
The last column on the table stated the length of time in minutes before the cockroach
died. The researcher noticed a great difference. Just like in 150 ml and 160 ml of ethanol,
it was 8.0 minutes and 15.0 minutes respectively. The experiment proved that the extract
with the lower volume of the alcohol have the highest capacity on the killing of the
cockroach. Hence, the volume of the alcohol greatly affected the efficiency of the extracts.
It was noted that the lesser the volume of the alcohol, the greater was its efficiency in
killing the cockroach.
4.2 Interpretation of the survey
The researcher developed questionnaires for 30 women respondents. They were
given samples to be tested on cockroaches and five questions to be answered. The
indicators of effectiveness could be seen in the survey conducted. For the number one (1)
question:
Did the cockroach die when sprayed with “kakawate” extract?
The 30
respondents unanimously said YES. That was an indication of the effectiveness of the
product. The number two (2) question: Was the “kakawate” extract an effective cockroach
killer? The 30 respondents all said YES. That was clear indication that the kakawate
extract was effective. In number three (3) question: If taught with the proper method of
Philippine Normal University – Center for Teaching and Learning
making the kakawate extract, will you do it on your own? Twenty five of the respondents
affirmed their agreement, while five of the respondents said NO. The researcher inquired
about the reasons for their answers. It was because they did not have the time to do it. In
the number four (4) question: Do you believe that the kakawate extract will not harm
people and the environment?, two respondents said NO. The others were unanimous in
saying that it was a safe alternative to the commercial pesticides.
Some respondents had favorable comments in question number five (5) like: “Sana
ay maituro sa bawat isa ang proseso nito upang mawala ang mga ipis na nakapagdudulot ng
sakit.; Effective; Environmental-friendly!; Ito na yung maganda malaman natin tungkol sa
kakawate. Makakatulong ito sa atin sa pagpatay ng ipis at mas mura. and Kakawate extract
is a better alternative to insecticide in the market. A Baygon of 600 ml costs P279.75, very
expensive and hazardous to health and environment.”
33
Philippine Normal University – Center for Teaching and Learning
Table 4. 2
Survey Results
SURVEY RESULTS
NUMBER OF RESPONDENTS = 30
QUESTIONS
YES
NO
1. Did the cockroach die when sprayed with
"kakawate" extract ?
30
(100%)
0
0%
2. Was the "kakawate" extract an effective cockroach
killer?
30
(100%)
0
0%
3. If taught with the proper method of making the
"kakawate" extract, will you do it on your own?
25
(83.37%)
5
(16.67%)
4. Do you believe that the "kakawate" extract will not
harm people and the environment?
28
(93.33%)
2
(6.76%)
5. Write comments or suggestions.
34
Philippine Normal University – Center for Teaching and Learning
CHAPTER V
SUMMARY, RECOMMENDATION, CONCLUSION
5.1 Summary
Gliricidia sepium, locally known as madre de cacao or kakawate, is a nitrogenfixing tree and easily grown in the localities just by cutting and planting it in the ground.
Studies revealed many uses of kakawate leaves like fertilizer, termite and rat killer, antifungal, and as an organic pesticide on diamond moth, as repellant to rice case worms and to
control sweet potato weevil. Dr. Alfredo Rabena, head of the Research and Development
Office of the University of Northern Philippines found out that the leaves of kakawate
contain coumarin that can kill almost all types of insects. And coumarin contains tannin
that is considered potentially anti-diarrhea, anti-dysenteric, anti-mutagenic, antioxidant,
bactericidal, hepato-protective, pesticide and act as an astringent.
Insecticides are any toxic substances that are used to kill insects but in some cases,
it is hazardous to people and the environment. Due to the rising cost of commercial
insecticides and the problem of leaving toxic residues on food, water and atmosphere, it has
become an objective of the researcher to develop and explore alternative control measures.
The study and experiment was done to prove that kakawate leaves or Gliricidia
sepium could be a potential insecticide because of its components. Healthy kakawate leaves
were gathered and ground. They were saturated for five hours in 70% ethanol, then filtered
and mixed with water to come up with the extracted kakawate to be sprayed on live
cockroaches. The efficiency of this organic insecticide was made through sample
35
36
Philippine Normal University – Center for Teaching and Learning
application with five cockroaches. It has been found out that appropriate concentration of
the leaves extract together with right amount of ethanol (150 ml only) caused the death of
the cockroaches at the fastest time (8.0 minutes). It was observed that the cockroach
aggressively reacted to it. They became hyperactive but at some point, they lost their
strength and suddenly stopped moving. Then after several minutes, they died.
It was
shown in the tabulated data that the extract of kakawate with lowest volume of 70%
ethanol (150 ml) had the highest capacity in killing the cockroaches. Hence, the volume of
the ethanol greatly affected the efficiency of the extract. The dark green kakawate and
ethanol extracts contained hydrolyzed tannin that acted as astringent that caused the
contraction of the tissues. It was the main reason why the dead cockroach was somewhat
bulgy and hard, and its feet were not stretched out
The researcher has achieved his general objective of coming up with an alternative
insecticide that is cheaper, organic and effective. This alternative and eco-friendly
insecticide came from the extracts of kakawate leaves.
5.2 Conclusion
The extracted dark green ethanol solution from the kakawate leaves (scientifically
known as Gliricidia sepium) was proven to be a potential organic insecticide. It contained
hydrolyzed tannin that act as an astringent that causes the contraction of tissues of the
cockroach. “Tannins are polyphenols that are obtained from various parts of different
plants belonging to multiple species. An astringent is a substance which causes biological
Philippine Normal University – Center for Teaching and Learning
tissue to contract or draw together. Tannins, such as those found in teas and wines, are also
astringents, since they cause the mouth to feel dry and constricted. Many of these tannins,
such as oak bark, are used to produce astringent products for both medical and cosmetic
use. (http://www.herbs2000.com/h_menu/tannins.htm).
According to Dr. Alfredo Rabena, head of the Research and Development Office
of the University of Northern Philippines, the leaves of the kakawate tree contains
coumarin, an effective botanopesticide. He found that kakawate leaves is a good source of
coumarine that can kill almost all types of pests and insects.
(http://www-
agribusinessweek.com/kakawate/leaf-an-effective-pesticide)
New World Dictionary defines coumarin as crystalline substance C9H6O2, with the
odor of vanilla, obtained from the tonka beans and certain plants or made synthetically.
Coumarin contains tannin that is also known as astringent.
Therefore, I conclude, that extracts from kakawate leaves have coumarin that
contains tannin. This is the reason why the dead cockroach was somewhat bulgy and hard,
and its feet are not stretched out.
The leaves, after extraction, turned pale green in color because the coumarin
containing tannin was dissolved in ethanol. The tannin was the one responsible for the
green plastic-like cover of the kakawate leaves. It served as their protection from their
predators; it was poisonous to some animals and even to human. Too much intake of
37
Philippine Normal University – Center for Teaching and Learning
tannins could cause severe problem on our stomach and liver. Wines, coffees and teas are
some common food containing tannin.
Upon spraying of the insecticide, kakawate plus ethanol solution, it was observed
that the cockroach aggressively reacted to it. Each one of the five cockroaches became
hyperactive but at some point, each one of them lost the strength and suddenly stopped
moving. Then, after several moments, each one of the cockroaches died. The different
concentration affected the efficiency of the product. I therefore, conclude, that the lower
the concentration, in terms of tannin from the leaves, the lesser was the tendency for it to
kill insects. It was also noted that the saturation in certain volume of ethanol affected
extracts’ performance.
5.3 Recommendation
The organic insecticide derived from the kakawate leaves or scientifically known
as Gliricidia sepium is a lot cheaper than the commercially available inorganic insecticides.
The researcher recommends using this kakawate extracts because first of all, it is cheaper.
A respondent said that a 600 ml of Baygon, a known brand of insecticide, costs P279.75.
Second, it is not as hazardous as the inorganic insecticides that cause severe damage, not
only to people but also to the environment, causing environmental pollution. Therefore, it
is environmental friendly. Third, it is easy to make. With a cloth as strainer and a container,
the grounded kakawate leaves with ethanol can be easily extracted. And lastly, it is easy to
find in the locality most especially in the provinces. It is easy to propagate because it has
38
Philippine Normal University – Center for Teaching and Learning
the characteristic of growing almost right away by cutting it and directly planting it in the
ground.
The researcher highly recommends the Gliricidia sepium or locally known as
kakawate extract as an organic insecticide and hopes that scientific research be made by
Department of Science and Technology so that a better but cheaper product will come out
in the market . This will lead to national progress by way of reducing the importation of
commercialized insecticide and preserving the environment.
.
39
Philippine Normal University – Center for Teaching and Learning
BIBLIOGRAPHY
Davidson, Ralph H. & Lyon, Willis. (1979). Insect Pests. New York: John Wiley & Sons.
Guralnik, David. (1980). Webster’s New World Dictionary. United States of America:
William Collins Publishers, Inc.
Mish, Frederick. (1997). The Merriam-Webster Dictionary. Springfield, Massachusetts,
USA; Merriam- Webster: William Collins Publishers, Inc.
Ross, Herbert, A. (1965). Textbook of Entomology. New York: John Wiley & Sons.
Sambatsiri, K & Pathumachatpat W. (1979). New Insecticides from Plants. Bangkok,
Thailand: Department of Entemology, Kasetsart University.
Aquino-Abros, Francisca. (May 1991).Effectiveness of Nerium Indicum as Insecticide to
House Pests Blatta Orientalis (Cockroaches). Thesis.
Beltran, Fidelismo. (May 1990). Effects of Soil Incorporation of Madre de Cacao Leaves
on Sweet Potato Weevil Manifestation, Growth and Yield of Sweet Potato. Thesis. p.2
Carino, M. B. (1981). Nine Composite Species for Insecticides. Thesis.
Cintura, Ligaya, et al. (March 2000). Madre de Cacao Extract as an Organic Pesticide on
Diamond Moth. Thesis. p.116
Coraza, Juanita. (March 2000). Performance of Mungo as Influenced by Time and Rate of
Application of Madre de Cacao as an Organic Fertilizer. Thesis. p.7
Ogot, Cleofe A.. (l989).The Control of Major Pest in Mushroom with the Use of Tobacco
Waste and Chemicals. Unpublished Doctoral Dissertation,
Rabena, Alfredo. (l997). The Isolation, Characterization and Identification of Active
Botano Chemicals of Kakawate Leaves Against Termites. Thesis.
40
Philippine Normal University – Center for Teaching and Learning
Manila Bulletin “House Pests” April 4, l991, Manila Bulletin Publishing Corporation
Intramuros, Manila p.14
Tacadena S. (May 22nd, 2010) Re: Kakawate lead an effective Pesticide
http;//www.agribusinessweek.com/kakawate-leaf-an-effective-pesticide
Tannins(n.d.) Retrieved Feb 2nd, 2012., from herbs 2000.
http://www.herbs2000.com/h menu/tannins.htm
Smith S.E. (n.d.) What is an Astringent? Retrieved Feb 2nd, 2012, from wisegeek.
http://www.wisegeek.com/what-is-an-astringent.htm
Insect Repellant (n.d.) Retrieved August 16, 2011, from free dictionary
http://www.thefreedictionary.com/insect+repellant
41