Caraway
Presented to:
Dr. Ablin
Date:
22 November 2010
Presented by:
Victoria Strain, Taylor Tryon, & Sandra Clark
Imagine the earliest Homo sapiens, the original nomads forced to fight and search for their
food using every available resource and plant to nourish their bodies. Until one day while
foraging for food they came upon a sage colored, slender plant. The top of the plant held
delicate, white fruiting bodies that gave appearance of a wild flower, but with a refreshing, spicy
fragrance. It was unknown to the earliest humans, but the caraway plant as it would later be
called was one of the first plants discovered.
It is found in many essential oils but is most prominent in the fruits of the caraway plant.
Perhaps the most distinguishable feature of the caraway fruit is its strong odor and distinct taste
that is prominent as a spice in breads. Caraway through the centuries has proven useful as a
stimulant that can be used to relieve flatulence, indigestion, menstrual cramps, laryngitis, etc.
and can also be used to aid in digestion, stimulate milk production in breastfeeding mothers, and
can also be used in aromatherapy (History of Caraway).
Carvone, given by the IUPAC name 2-Methyl-5-(1-methylethenyl)-2-cyclohexenone and
Chemical Abstract Service number 2244-16-8, is a member of the family of chemicals called
terpenoids. Caraway, whose molecular weight is 150.22 g / mol, has a boiling point of 231 °C
and melting point of 22.5 °C and a density of .91 g/ ml. Its seeds are brown with a rough
appearance and texture and its oil is a pale yellow/ translucent liquid. When in oil form it is
normally soluble in alcohol and oils but rather insoluble in water (MSDS Caraway).
However, because the carvone molecule has two mirror image forms or enantiomers,
there are also two specific odors that are associated with each respective enantiomer. The R-(-)
enantiomer smells like spearmint whereas its mirror image, the S-(+) carvone molecule, smells
of caraway. This is an interesting concept that the enantiomers of the same molecule would have
differing perceived smells. This in itself is a proof that the olfactory receptors within the nose
must have chiral centers in order to allow for an increased ability to perceive differences in
enantiomers of the same molecule. These chirality centers will be discussed specifically in the
coming paragraph.
Specifically, carvone is an organic molecule containing many various bond types and
functional groups which all contribute to its characteristics that were described above. Carvone
contains 11 sigma bonds and three pi bonds, a six carbon ring containing one double bond
within, and a single chirality center at the third carbon on the ring as shown in the structure
below:
(R)
(S)
CH3
CH3
O
O
H2C
CH3
H3C
CH2
It is this tetrahedral stereogenic chirality center that allows for the dual nature of the
compound carvone and its ability to be perceived as either spearmint or caraway. This paper will
be focusing more specifically on the S-(+) enantiomer which attributes to caraway. The molecule
also contains two specific functional groups: a ketone stemming from the first carbon on the ring
and an alkene stemming from the beta carbon of the chiral center. There is also an internal alkene
within the ring. These pi bonds lend the molecule susceptible to various oxidation and reduction
reactions that could lend useful in organic chemistry studies.
The biosynthesis of caraway, as seen below, is a complex process involving many
different enzymes used to create Carum carvi, a volatile oil made up of a ketone, carvone,
terpene, and D-limonene that is imperative in the synthesis of caraway. The monoterpenes of
limonene and carvone are synthesized in the process of making caraway. Caraway is
synthesized through the oxidation of limonene. The way carvone and limonene accumulate is
due to changing levels of enzyme activity during the development process. First, only limonene
accumulates because the enzyme that converts limonene is inactive. Later, both limonene and
carvone accumulate and the ratio of each component’s formation depends on the activity of the
enzymes in the pathway. Finally, when limonene and carvone has stopped forming, some of the
enzymes in the pathway become inactive. Also, the formation of other components, such as
proteins and starch may direct the flow of carbon away from the biosynthesis process
(Bouwmeester, paraphrase).
Biosynthesis of S+ Carvone
An important method of compound determination is by comparing the structure to the
infrared (IR) spectrum. Show below is the IR of caraway.
The structure of caraway has a C=O. This can be seen in the peak in the 1650-1800 range.
Caraway also has many C-H bonds which can be seen in the 3000 range. The peaks seen in the
IR spectra of caraway below 1500 correspond to the C-C single bonds which are present multiple
times in the structure (Smith 474-79).
As seen in the table below Caraway as a whole is a relatively safe compound. Originally
found in nature it has a low reactivity, a low flammability and no carcinogenic, mutagenic or
developmental effects. The health hazard of one is due to a few minor concerns. The first is
associated with the fact that when burning it may release carbon dioxide or carbon monoxide
which can be hazardous upon consumption or prolonged association. Secondly, upon repeated
exposure to the skin or eyes, dermatitis (inflammation of the skin) or an allergic dermatological
reaction can occur.
Material Safety Data Sheet: Caraway
Health Hazard
1 Irritation or minor reversible injury possible.
Flammability
0 Materials will not burn.
Reactivity
0 Low hazard.
However, since it is primarily employed for the food and medicinal industry, the USDA has set
that ingestion of any form of caraway through seed, plant or oil not exceed 0.02 % of the
nutritional diet.
As one of the oldest plants in existence, caraway is still frequently used for both
nutritional and medicinal purposes. An enantiomer of carvone, it has a refreshingly spicy scent
and taste. It also safe to use in the environment and non-toxic to humans in small levels. Overall,
caraway has a variety of different uses, functional groups, and is a very interesting compound.
Works Cited
Bouwmeester, Harro J., Jonathon Gershenzon, Maurice C.J.M. Konings, and Rodney Croteau.
"Biosynthesis of the Monoterpenes Limonene and Carvone in the Fruit of Caraway . I.
Demonstration of Enzyme Activities and Their Changes with Development -Bouwmeester Et Al. 117 (3): 901 -- PLANT PHYSIOLOGY." PLANT PHYSIOLOGY®.
American Society of Plant Physiologists, 1998. Web. 15 Nov. 2010.
<http://www.plantphysiol.org/cgi/content/full/117/3/901>.
Caraway – Uses, Benefits and Some Properties for Caraway.” Health Care Tips – Diseases &
Conditions, Herbal Medicines, Herbal & Home Remedies. 10 Nov. 2010. Web. 15 Nov.
2010. http://www.health-care-tips.org/herbal-medicines/caraway.htm.
"CAS REGISTRY and CAS Registry Numbers." CAS, Chemical Abstracts Service Home Page.
American Chemical Society, 8 Nov. 2010. Web. 15 Nov. 2010.
<http://www.cas.org/expertise/cascontent/registry/regsys.html>.
"Herb of the Month: Caraway Carum Carvi." International College of Herbal Medicine. Sept.
2006. Web. 15 Nov. 2010. <http://www.herbcollege.com/herbofthemonth.asp?id=96>.
"History of Caraway." Our Herb Garden: Favorite Culinary Herbs. Our Herb Garden, 2008.
Web. 15 Nov. 2010. <http://www.ourherbgarden.com/herb-history/caraway.html>.
"Material Safety Data Sheet: Caraway." University of Victoria. Spectrum, 12 May 2005. Web. 11
Nov. 2010. <http://web.uvic.ca/~pmarrs/chem235/caraway%20oil.pdf>.
Smith, Janice Gorzynski. Organic Chemistry. Boston: McGraw-Hill, 2008. Print
GRADING
CATEGORIES
Structure (20%)
Exemplary
Stereochemistry and
bond types(10%)
All bond types
and chirality
centers identified
correctly
All spectra
included; data
identified
correctly
Infrared and/or NMR
spectroscopy (10%)
All functional
groups and bond
types identified;
formula drawn in
ChemSketch or
other drawing
program
Synthesis or biosynthesis Logical synthesis
(5%)
included
Properties and uses (CAS All data and
No., M.W., density, mp, major uses
bp, solubility, color)
included
(10%)
Health/environmental
Accurate,
effects of flavor (10%) relevant, and
thorough
information
Risk/benefit analysis
Major risks
(MSDS information,
identified
effects of toxicity) (10%)
References and
All sources listed
documentation(Minimum and one attached;
: one online and one
proper citations
journal) (10%)
including date of
access; no
plagiarism
Competent
Acceptable
Unacceptable
Not
Attempted
Most functional Some functional groups Few functional No structure
groups and bond and bond types
groups and bond included;
types identified; identified; structure
types identified; functional
structure drawn in drawn in ChemSketch structure not
groups not
ChemSketch or or other drawing
drawn with
identified
other drawing
program
ChemSketch or
program
other drawing
program
Most bond types Some bond types and Incorrect
Not
and chirality
chirality centers
identification of attempted
centers identified identified correctly
bond types and
correctly
chirality centers
Most spectra
Some of the data
Data inaccurately No data
included; data
included and identified presented
included
included and
correctly
identified
correctly
Partial synthesis Partial synthesis
Wrong synthesis Not
included
attempted but some
attempted
steps incorrect
Most data and
Some data and uses
Minimal data and No data
uses included
included
uses included
included
Accurate and
relevant
information
Information partially
accurate
Inaccurate
information
None
included
Most risks
included
Some risks included
Incorrect risks
Not
attempted
Most sources
Some sources listed;
listed; appropriate appropriate citations;
citations; few
few minor errors; no
errors; no
plagiarism
plagiarism
Writing (10%)
Demonstrates
excellence and
creativity in
writing with no
errors
Presentation (5%)
Computer
Neat, computer
generated paper; generated paper
excellent
presentation
Total (100 % possible)
No sources listed References
and only one
not attached;
attached; major no primary
errors or sources reference;
quoted incorrectly sources not
quoted
Demonstrates
Adequate writing with Numerous writing No attempt
proficiency in
few errors
errors
made to
writing with only
present
minor errors in
acceptable
writing
writing
Adequate presentation; Inadequate
computer generated
presentation
Completely
unacceptable
presentation