Abstract
Today over one billion people worldwide are at risk for tropical diseases caused by parasitic organisms. The World Health Organization (WHO) now classifies many as neglected tropical diseases, having an enormous impact on socioeconomic development and quality of life at all levels particularly in developing countries. Malaria, leishmaniasis and human African trypanosomiasis are still major public health problems in need for new and more effective drugs. The aim of this study was to exploit traditional healer knowledge and evaluate
in vitro
antiprotozoal activity of twenty-five medicinal plants collected from Saudi Arabia and the island Soqotra. The plants were extracted with methanol and screened for their
in vitro
antiprotozoal activity against erythrocytic schizonts of
Plasmodium falciparum
, intracellular amastigotes of
Leishmania infantum
and
Trypanosoma cruzi
and axenic
T. brucei
trypomastigotes. To assess selectivity, cytotoxic activity was determined against MRC-5 cells. Criteria for activity were an IC
50
< 10 µg/ml. Selective activity was obtained for
Chrozophora oblongifolia
(Del.) A. Juss. ex Spreng.,
Dracaena cinnabari
Balf. f.,
Ficus ingens (Miq.), Hypoestes pubescens
Balf. f
., Lavandula dentata
L.,
Plectranthus barbatus
Andr. and
Punica protopunica
Balf. f. against
P. falciparum
(IC
50
2 – 8 µg/mL) while
Dracaena cinnabari, Euriendra balfourii
Cogn. & Balf. f.,
Grewia erythraea
L. and
Vernonia leopoldii
Vatke displayed activity against the three kinetoplastid parasites (IC
50
< 10 µg/mL).
Acridocarpus socotranus
Oliv. was moderately active against
T. brucei
(IC
50
3.5 µg/mL).
Ballochia atrovirgata
Balf. f.,
Dendrosicycos socotrana
Balf. f.,
Dracaena cinnabari
and
Euphorbia socotrana
Balf. f. displayed non-specific inhibition of the parasites related to high cytotoxicity.
Acknowledgments: The authors extend their appreciation to the NPST program by King Saud University for funding the work through the project number (10-MED1288 – 02). The authors gratefully acknowledge that financial support.