Lec.8
Dr. Saad Ali Ihsan
Types of Natural Antibiotics
using traditional herbs and plants as natural antibiotics is a
practice now being supported by modern science. As
pharmaceutical antibiotics cause an increasing number of
side effects in people, such as digestive problems, allergies,
decreased immune function and antibiotic-resistant microbes
such as MRSA, doctors and patients are both looking for new
alternatives in the fight against infections. Some plants have
been supported by medical research to actively fight a range
of bacteria and viruses, while stimulating our own immune
defenses at the same time.
1. Garlic (allium sativum)
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Considering that garlic can be cheaply purchased and
consumed daily as a food, this makes it a truly effective and
economical immune support. In addition to stimulating white
blood cells, garlic is effective against a range of microbes,
including candida albicans, e. coli, salmonella, influenza, the
common cold virus and staphylococcus aureus. Researchers
Vinay Kumar Sharma, Ph.D. and Amit Kumar, Ph.D. published
findings in "The Journal of Nutritional Science and
Vitaminology" in 1999 that showed garlic was also an
effective antimicrobial agent against antiobiotic-resistant
strains of bacteria such as MRSA. Note: Garlic may reduce
blood pressure in some people, and should be avoided by
people taking warfarin.
2. Echinacea root (echinacea spp.)
The root of Echinacea is rich in plant chemicals that stimulate
the production and synthesis of white blood cells within the
body. Because of this, Echinacea is beneficial in supporting
recovery from all infectious diseases, as it strengthens
natural defenses against microbes. Researcher Sachin Shah
and colleagues from the University of Connecticut published
findings in the prestigious medical journal "The Lancet" in
2007 that showed purple Echinacea was effective in reducing
both the incidence and duration of the common cold.
3. Goldenseal (Hydrastis canadensis) and Barberry (Berberis
canadensis)
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Barberry and goldenseal share a common chemical called
berberine that fights infection. This chemical is antiviral,
antibacterial, antiprotozoal and antifungal, supporting the use
of these two plants in treating colds, flus and other infections.
According to Hyeon-Hee Yu and colleagues who published
their study in "The Journal of Medicinal Food" in 2005,
berberine was used alongside antibiotics in treating MRSA
(Methicillin-resistant Staphylococcus aureus ) .This
combination was found to be more effective in treating MRSA
than when using the antibiotics alone. Note: Goldenseal may
increase blood pressure, and should be avoided in those
taking blood pressure medications.
4. Tea tree oil (Melaleuca alternifolia)
Tea tree oil is an essential oil made from the leaves of the
Australian plant Melaleuca alternifolia. When diluted in a base
of carrier oil, cream or ointment, tea tree oil can be used for
its potent antibacterial, antifungal, antiviral, antiprotozoal and
anti-inflammatory properties externally. Tea tree is effective
against salmonella, e. coli, candida albicans, MRSA, tinea
pedis, herpes simplex and trichomonas vaginalis. In a review
of scientific research published in "Clinical Microbiology
Reviews" in 2006, researcher C.F. Carson and colleagues
from the University of Western Australia found that the
majority of research supports the topical use of tea tree oil in
fighting microbes.
5. Manuka Honey
Manuka honey comes from a plant native to New Zealand and
contains a chemical called "Unique Manuka Factor" which
makes it effective as a tissue healer and antibacterial agent
for treating wounds, ulcers and burns. According to Talal
Alandejani, M.D. and colleagues who published research in
the scientific journal "Otolaryngology" in 2008, manuka honey
was more effective than antibiotics when treating a range of
bacteria, including MRSA.
6- Propolis
Propolis is a mixture of natural resins that bees collect from
flower buds, plant sap and other plant sources. They use it
not only to seal small gaps in the bee hive, but also to prevent
decomposition within the hive. For example, if a small animal
like a lizard enters the hive and dies there, the bees would
seal it with propolis - making it like a mummy - and rendering
it harmless and odorless.
7- Olive leaf extracts
In recent years, olive leaf and olive leaf extracts (OLE) have
become popular health supplements. They are said to be
powerful antioxidants, with one 2005 study by Dr L Stevenson
of Southern Cross University, Australia, reporting it to be
twice as powerful an antioxidant as green tea and four times
more powerful than Vitamin C.
And yes, olive leaf extracts are also claimed to enhance
immune function and act as natural antibiotics - and also
as anti-virals and anti-parasites.
8- Colloidal silver
Yet another product widely marketed (usually by multi-level
marketing companies) as an alternative to antibiotics is
Colloidal Silver. This is NOT something that I would
recommend, but I feel it is useful to discuss it here because it
is quite widely touted.
9- Hydrogen peroxide ( H2O2 )
If you don't mind something that is perhaps not totally natural
- in the sense that it is not normally consumed as food – then
hydrogen peroxide is a good option. It is effective,
inexpensive and, if used properly, perfectly safe.
Used properly means, for example, putting a drop or two of
pharmaceutical grade 3 percent hydrogen peroxide inside the
ear canal. Let it bubble for about two minutes, then tilt your
head to drain it off. With its natural antibiotics and anti-viral
properties, this can help prevent a flu from becoming fullblown if it is administered in the early stages.
When you already have a flu, it helps to regularly sip highly
diluted hydrogen peroxide - a few drops of already diluted 3
percent hydrogen peroxide, added to a big jug of water. Take
one or two sips regularly throughout the day.
Killing bacteria in the atmosphere
Besides killing bacteria inside your body, there may be times
when you want to destroy them in the air - for example, to
disinfect your home when someone at home is ill with an
infectious disease.
This is where essential oils come in handy as very powerful
natural antibiotics. While bacteria and viruses have evolved
into "superbugs" that are resistant to powerful
drugs, none are known to have become resistant to essential
oils. That's how potent and useful essential oils are.
Essential oils usually refer to pure, aromatic oils extracted
from herbs and spices. But they also include the oils of other
plant products, such as lemon oil, or tea tree oil - which is one
of the most powerful known disinfectants. Helpful essential
oils for destroying bacteria and viruses include the oils
of lemon, oregano, thyme, pine, cinnamon, cloves,
peppermint, lavender, rosemary and tea tree.
Most essential oils are too potent for direct human
consumption. It is okay - and beneficial - to eat the herbs and
spices from which these oils are extracted, but not ok to
consume the oils directly.
So one way to use these essential oils as natural antibiotics is
to spray into the atmosphere. This, alone, is often good
enough to destroy the bacteria and viruses present within one
or two minutes. Another way is to add a few drops into a
dehumidifier, atomiser or aromatherapy burner, and let it run
for a few hours.
And if you are wearing a flu mask, it would also be helpful to
add a few drops of essential oils to your mask, so that you
breathe in clean, disinfected air. Alternatively, add a few
drops to your hankerchief and breathe through it every now
and then.
As you can see, there are lots of natural antibiotics to choose
from. And many of these are actually more effective than the
synthetic, unnatural and harmful antibiotics being peddled by
the pharmaceutical industries.
Biosynthesis of Penicillin’s :
The amino acids ( Cysteine & Valine ) are incorporated into
the ( 6 – aminopencillanic acid ) portion of pencillin
molecules, and the acyl group of pencillin G ( Benzylpencillin
) is derived from phenylacetic acid. As in Fig. ( 11 – 8 ) the
tripeptide, is the precursor of isopencillin N, Epimerization of
the side chain yields pencillin N.
In pencillin producting pathways, the side chain is
subsequently cleaved at the amide bond and replaced with
phenylacetic acid to yield pencillin G.
In cephalosporin biosynthesis pathways,
enzyme called
an
(Desacetoxycepnaiosporin C. synthase ) (
DOAC synthase or expandase ) acts upon pencillin N to
generate the six – membered ring characteristic of
cephalosporins. Further modification of the methyl group on
this ring eventually yields Cephalosporins.
The antibiotics which containing the B-lactam nucleus were
solely the domain of fungi ( Pencillium & Cephalosporium ),
we now know that many types of B-lactam metabolites are
found also in several species of streptomycetes and some
non-actinomycetes prokaryotes as well .
Biosynthesis of Tetracycline’s :
Studies confirmed that tetracycline antibiotics originated
through acetatemalonate metabolism. These pathways
involve head-to-tail condensation of two carbon units to form
intermediates termed “Polyketides.” Their formation deviates
from the fatty acid pathway by a disruption or lack of a normal
reduction-dehydration-reduction sequence as the chain
elongates. Subsequent metabolic steps yield the
characteristics constituents. Mutant strains of tetracycline
producing have been selected for genetic blocks in the
biosynthetic pathway and have been used to clarify a number
of the sequential steps.
Its believed that a malonamyl-CoA residue serves as a primer
and that eight malonate units undergo stepwise
condensations with the addition of C-2 units and
decarboxylation to yield a liner C-19 polyketide ( Fig. 11 – 13 )
P.256 .
Carbonylmethylene condensations yield the tetracyclic
pretetramide nucleus. Methylation of the C-6 position of the
pretetramide is an early step in the biosynthesis of most
tetracyclines, but this step is omitted in the formation of the
naturally occurring demethyltetracyclines. Hydroxylation of
the C-4 position and dearomatization to yield a 4-keto
intermediate appears to precede 7-chlorination. Halogenation
must precede introduction of the 4-amino group, which is
methylated stepwise. Terminal reactions in the biosynthetic
sequence are hydroxylation at C-6 and reduction of a double
bond in ring B; it is interesting to note that the presence of a
7-halogen substituent apparently inhibits 5-hydroxlation.
( Fig. 11 – 13 ) show that :
Polyketide ______________ 6 – methylpretetramide
___________ ( Compound ) _____________ ( Compound )
____________ (Compound) ___________ Chlortetracycline.
Isolation & Purification of Antibiotics :
Liquid – liquid extraction using some water – immiscible
organic solvent is the approach utilized for most antibiotics.
Highly polar antibiotics such as neomycin and other
aminoglycoside antibiotics, are usually recovered from the
culture broth by adsorption on some suitable adsorbents .
Many adsorbents remove antibiotics of this type from culture
broths with varying degrees of selectivity. Use of charcoal of
controlled activity grades and elution of the antibiotic with
dilute acid is a typical example of this isolation approach.
Once the crude antibiotics has been recovered from the
nutrient broth, it is subjected to chromatography,
recrystallization, or other standard manipulations to effect an
appropriate degree of purification. It should be noted that
attainment of chemical purity is usually considered
impractical and unnecessary for therapeutic purposes.
Separation of closely related antibiotics molecules is often
unfeasible. The presence of up to 6% chlortetracycline in
commercial tetracycline represents a practical application of
such purification considerations. Accepted standards of
purity for antibiotics and antibiotic preparations are
controlled by the United States Pharmacopoeia. Qualitative
and quantitative evaluations of antibiotic preparations for
adherence to established standards utilize both biologically
and chemically based tests. Calorimetric and
spectrophotometric approaches and definitive measurements
have largely replaced microbiologic assay and arbitrary units
for quantitative purposes.
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