Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : In-vitro antimalarial and antiamoebic potential of plants of medicinal value present in the desert ecosystem : a case study from Rajasthan

Auteur : Sharma, Poonam

Université de soutenance : Jawaharlal Nehru University

Grade : Doctor of Philosophy (PhD) 1999

Sommaire partiel
1. An extensive and exhaustive review (1912-1999) based on conventional botanical descriptions, phytochemistry of their extracts and scientific parameters of dose dependence in vivo and in vitro, of antimalarial and antiamoebic plants along with their common antiprotozoal features has been listed.
2. The ethnobotanical information was gathered by direct field interviews of old villagers, ladies, the professional singers (Barots) and local healers (Gunijis and Vaidyas) practicing traditional medicine in the last half century. The most commonly described antipyretic plant was Calotropis procera .. The intact buds and flowers, roots burnt in mud-pots, and latex beads picked up from the sand are being used in fever. Similarly the plant Commiphora wightii was chosen to test its antiamoebic activity based on its mention in ethnobotanical information (Sharma 1995).
3. C. procera is a wild weed while C. wightii is a conserved plant with some socioeconomic benefits. C. procera is distributed widely in nature and may be one of the only available medicinal plants in a desert ecosystem and finds a place in folklore. C. wightii has however found a limited place in the pharmaceutical market.
4. Since plants have been found active against one particular organism can possess a broad spectrum of antiprotozoal activity against other organisms, so both the plants C. procera and C. wightii were tested against P. falciparum and E. histolytica. These two pathogens which are prevalent in the region are also easier to cultivate in the laboratory.
5. The preliminary phytochemical screening for C. procera leaves, roots, stem, flower and bud extracts showed most commonly found classes of compounds, while with the gum-oleo resin extract of C. wightii the alkaloids were absent. Peroxides, commonly known to be present in other antimalarial plants like Artemisia were conspicuous by their absence in both these plants.
6. All the ten standard antimalarial drugs tested showed activity at 30 to 3000 times lower doses of IC50 (0.00032-4.914 f. !g/ml) for MRC P.f 20 and IC50 (0.0047-4.959 ).tg/ml) ) for MRC P.f 76. The individual variations between the chloroquine related drugs and artemisinin related drugs were not significant. However the Artemisinin related drugs showed a better dose response for MRC P.f. 76. 109 0ummar !l and Conclusion
7. A significant variation was found in the in vitro antiplasmodial activity between different fractions and different parts of the two plants when tested using Analysis of Variance, which was further tested by Tukey’s test, for the two isolates of P. fa/ciparum, Statistical significance was also found for the dose effective responses for antiamoebic activity with E histoiytica in vitro.
8. Of the six ethanolic extracts flower ethanol extract (IC50=0.112 mg/ml and 0.519 mg/ml) is found to be the most active followed by budethanolic extract (IC50=0.122 mg/ml and 0.684 mg/ml) in both the CQ sensitive MRC P. f. 20 and CQ resistant MRC P.f. 76 isolates respectively. Among the total 23 fractions, gum hexane (IC50=0.0068 mg/ml and 0.301 mg/ml ) is the most effective against both the isolates of P. falciparum. These may be studied further to purify and isolate the active component responsible for antiplasmodial activity from these crude extracts.

Mots clés : Environmental science Antimalarial, antiamoebic ecosytem desert

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