Large-scale<i>in Vitro</i>. Screening of Egyptian Native and Cultivated Plants for Schistosomicidal Activity

In vitro. bioassay screening of 346 methanol extracts originated from 281 native and cultivated plant species growing in Egypt, and related to 81 families, was carried out for schistosomicidal activity. The extracts were bioassayed at 100 µg/mL on viable Schistosoma mansoni. mature worms in culture medium. Viability of worms was examined after exposure for 24 h, and mortality determined. Negative (DMSO) and positive (praziquantel) controls were used. Of the tested plant extracts, 72 were found to possess reproducible in vitro. antischistosomal activity. These active extracts were further subjected to determination of their LC50 and LC90 values. Strong antischistosomal activity was found in the extracts of 15 species (possessing LC50 ≤ 15 µg/mL), viz. Agave americana. L. var. marginata. Trel. (Agavaceae), A. lophantha. Schiede (Agavaceae), Furcraea selloa. C.Koch. (Agavaceae), Calotropis procera. (Aiton) W.T.Aiton (Asclepiadaceae), Pergularia tomentosa. L. (Asclepiadaceae), Asclepias sinaica. (Boiss.) Muschl. (Asclepiadaceae), Alkanna orientalis. (L.) Boiss. (Boraginaceae), Khaya grandifoliola. DC. (Meliaceae), Swietenia mahogani. (L.) Jacq. (Meliaceae), Pimenta racemosa. (Mill.) J.W.Moore (Myrtaceae), Pinus canariensis. C.Sm. (Pinaceae), Verbascum sinaiticum. L. (Scrophulariaceae), Solanum elaeagnifolium. Cav. (Solanaceae), S. nigrum. L. (Solanaceae), and Brachychiton rupestris. (Lindl.) K.Schum. (Sterculiaceae). These 15 species could represent promising bioactive sources that deserve further investigation, with the aim of finding novel antischistosomal agents. The current study represents the first report on a systematic screening of schistosomicidal activity utilizing a large number of plant species.