| dc.description.abstract | 11
th
NAPRECA Symposium Book of Proceedings, Antananarivo, Madagascar Pages 9-19
Midiwo et al.
9
Phytochemical Evaluation of So
me Kenyan Medicinal Plants
J. Ogweno Midiwo, A. Yenesew, B.F. Juma
Kerubo L Omosa, Irene L Omosa, Daniel Mutisya.
Department of Chemistry, University of Nairobi,
P.o. Box 30197, Nairobi. Kenya.
E-mail: jmidiwo@uonbi.ac.ke
Abstract
There are more than 1200 described medicinal pl
ants in Kenya from a flora of approximately
10,000 members. Strong cross-medical informati
on from the 42 ethnic groups points to the high
potential of some of these species.
The Myrsinaceae are well established ethno-anthel
mintics and anti-bacterials. They are
harbingers of long alkyl side chain benzoquinones
which clearly have a protective function from
their histochemical disposition. The main benzoqui
none in the sub-family Myrsinodae is embelin
while for the Maesodae it is maesaquinone together
with its 5-acetyl derivative; the distribution
of these benzoquinones by their alkyl side chain le
ngth or the presence / absence of 6-methyl
group is in accord with morphological sub-fam
ily de-limitation. The benzoquinones showed anti-
feedant, anti-microbial, phytotoxic, acaricidal, in
secticidal and nematicidal activity. Many other
benzoquinones of medium and mi
nor concentration were also
isolated and characterised.
Some plants belonging to the Polygonaceae which
are widely used as ethno-anthelmintics have
been studied. The common anthelmintic anthraquinones were obtained from all five Rumex
species while the naphthalenic acetogenin deriva
tive, nepodin was more selectively distributed.
The leaf of
Polygonum senegalense
is upto 17% surface exudate; about thirteen non polar
flavonoid derivatives (chalcones, di
hydrochalcones, flavanones and
a flavone) have been isolated
from it. From the internal aerial tissues of
this plant, the major flavonoids were common
flavonoids, quercetin, kaempferol, luteolin a
nd their glycosides. The only unique compound
isolated from this plant was 2'-glucosy
l-6'-hydroxy-4'-methoxychalcone whose aglycone,
uvangolatin is part of the exuda
te mixture. Other leaf exuda
te plants studied included the
stomach-ache medicine,
Psiadia punctulata
(Compositae) from which novel methylated
flavonoids, kaurene and trachyloba
n diterpenes have been found. | en |
