Effects of Mondia Whytei aqueous root extract on isolated rabbit heart and Jejunum preparations
View/ Open
Date
2005Author
Githinji, Charles G
Type
ThesisLanguage
enMetadata
Show full item recordAbstract
Mondia Whytei is a forest floor plant with aromatic rhizomatous roots. It belongs to the
Asclepiadaceae Family. Its roots are rich in bioactive phytochemicals. essential minerals
and vitamins. Among the bioactive phytochemicals that have been isolated so far, 2-
hydroxy-4-methoxybenzaldehyde is known to be responsible for the taste characteristics
of Mondia Whytei root extract.
Monilia Whytei roots were harvested. dried and powdered. 100 mg of this powder was
extracted with 500 ml water and subsequently freeze-dried. The freeze-dried extract was
then reconstituted with physiological salt solutions immediately before carrying out the
experiment. Fifteen California white rabbits were sacrificed with the exclusion of the
pregnant ones.
The objective of the study was to evaluate the overall effects of Mondia Whytei aqueous
root extract on the three kind of muscles in vitro namely skeletal, smooth and cardiac
muscles. The set-ups involved isolated rabbit heart and jejunum preparations that were
mounted in an organ bath.
Previous preliminary experiments with phrenic nerve diaphragm had showed that the
extract have no effect 01'1 the skeletal muscle neuromuscular junction.
On the isolated rabbit heart preparation the size (height) of the twitch represented the
heart force whereas the frequency of the twitches represented the heart rate.
Mondia Whytei root extract was found to reduce both the heart force and the heart rate.
The data obtained was used to plot the graph of: -
(i) Percentage drop in the heart force versus concentration of Mondia Whytei.
(ii) Percentage drop in the heart rate versus concentration of Mondia Whytei.
The 'best line of fir was preferable in data analysis since the data collected fanned a
scatter diagram.
Above the dose of 4.8 mg Mondia Whytei aqueous root extract caused ceasation of
myocardial contractility or the heart but at low doses it exhibited both negative
chronotropic and ionotropic effects. Conclusively, the overall effect on both the heart and
the jejunum were parasympathomimetic effects
The amount of Mondia Whytei that effectively reduced the heart force by half the original
force (EDso) was calculated and determined to be 3.6 mg whereas the ED50 for heart rate
was calculated to be 5.25 mg of freeze dried Mondia Whytei extract.
On isolated rabbit jejunum, Mondia Whytei aqueous root extract caused contraction but
the organ recovered its intrinsic activity over a period of ten minutes. It was also
observed that the jejunum recovered from the effects (contraction) of Mondia Whytei
even without washing it suggesting the probability of having some degrading enzymes
that rendered the extract inactive.
Further scientific work therefore ought to be done in order to isolate pure compounds and
elucidate mechanisms through which Mondia Whytei aqueous root extract mediates the
effects presented here and also analyze its toxicological profile.
Citation
Githinji, C.G(2005). Effects of Mondia Whytei aqueous root extract on isolated rabbit heart and Jejunum preparationsSponsorhip
University of NairobiPublisher
College of Health Sciences, University of Nairobi
Description
Msc-Thesis