Extraction of Jamaican plants
Since its inception, the Chemistry Department at Mona has been
involved in research in natural products chemistry.
One of the most enduring projects in this area is that involving
the chemistry of plant species belonging to the croton genus.
In fact, five generations of postgraduate students have been
involved in these studies, which were initiated by Professor
Wilfred R. Chan (now retired from UWI, St Augustine, Trinidad)
who was recently honoured for his invaluable contribution to
Chemistry at UWI and the region.
Pharmaceutical companies have recently shown a resurgence of
interest in plant derived chemicals and over the last few years,
thousands of plant extracts have been put through elaborate and
costly biological screening programmes in the search for new
compounds showing biological activity against viruses, bacteria,
fungi and other microorganisms which are deadly to man.
It is hoped to be able to show some of this work including
GC's, HPLC's and spectra, etc. soon.
Just to whet your appetite(?) What do you know about:
| Aloe vera |
(sinkle bible, sempervivum, Aloe vulgaris) |
| Bitter bush |
(Eupatorium villosum) |
| Bitter wood |
(Picrasma exelsa) |
| Cerasee Leaves |
(Mormodica balsamina) |
| Coralilla, Coralita |
(Antigonon leptopus) |
| Crotons |
|
| Dandelion |
(Stinking weed, piss-a-bed, Cassia occidentalis |
| Dog blood |
(Ravina humilis) |
| Fresh cut |
(Justicia pectoralis) |
| John Charles |
(Hyptis verticillata) |
| Love bush |
(Cuscuta americana) |
| Marijuana |
(Cannabis sativa) |
| Mistletoe |
(Oryctanthus occidentalis) |
| search my heart |
(Rytidophyllum tomentosum) |
| Shama lady |
(Mimosa pudica) |
| Trumpet tree |
(Cecropia peltata) |
The genus Croton belongs to the family Euphorbiaceae (which has
about 700 species); a family well known for producing compounds
with diverse biological activity and elaborate and interesting
structures.
Members of the genus have been used in folk-medicine in Jamaica,
North, Central and South America - and in some countries in the
Far East and Africa.
A number of Croton species have been investigated chemically
yielding a variety of interesting compounds, mainly alkaloids and
terpenoids.
Examples of Jamaican Crotons that have been investigated
include:
C. corylifolius
C. nitens
C. linearis
C. humilis
C. flavens
C. wilsonii
C. discolor
C. lucidus
The first four have yielded a number of diterpenes, while the
last four have yielded some alkaloids.
C. corylifolius was one of the first members of the genus to be
investigated. In that study a novel goup of diterpenes with a
hitherto unknown carbon skeleton was isolated and characterised.
The new skeleton was named Crotofolane and since the original
work which produced compounds crotofolin A, B, C, D a fifth
crotofolin has been isolated called crotofolin E.
The herbaceous plant, Justicia pectoralis (Fresh Cut) a
member of the Acanthaceae family is used in folk-medicine for
ther treatment of cuts and other ailments, including colic,
consumption and flu. Preliminary studies on the plant juice and
crude acetone extract revealed that the blood clotting time was
significantly increased by these agents. The leaves and stems of
the plant contain a coumarin as its major component. Flesh wounds
created on Wistar rats and tested with the coumarin, extracted
from the plant, showed less inflammatory process and enhanced
wound-healing compared with control rats. This suggests that the
use of this herbaceous plant influences the wound-healing
process.
Marijuana
The principal active constituents in marijuana have been
investigated since 1899, but the first pure-form isolation of
tetrahydrocannabinol (THC) was not reported until 1964.
A Mass Spectrum of Δ-9-THC
in JCAMP-DX format is available from here.
The cannabinoids are stored for the most part in the tiny,
glandular hairs on the top of the plant.
It is claimed that the average "joint" made from marijuana grown
in the U.S.A., contains about 2.5 to 5 mg of THC.
More information is available on:
the biochemical aspects of the effect of marijuana,
and again here.
A report from the DEA noted that
"Marijuana has no currently accepted
medical use in treatment in the United States" .
A 1999 study on the Science base for "medicinal marijuana" is available at the US.
National Acad. of Sciences
THC was featured as the April 1996 Molecule
of the Month (MOTM).
Images of plants and identification of constituents have been
published by Michael Moore at the SouthWest School
of Botanical Medicine
Return to links to the chemistry of other
Jamaican items, including spices and fruit and vegetables.
Return to Chemistry, UWI-Mona,
Home Page
Copyright © 1995-2013 by Robert John
Lancashire, all rights reserved.
Created and maintained by Prof. Robert J.
Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created Feb 1995. Links checked and/or last
modified 23rd November 2013.
URL
http://wwwchem.uwimona.edu.jm/lectures/herbrem.html
