Abstract

SCREENING OF EXTRACTS FROM ENDEMIC SOCOTRAEN MEDICINAL PLANTS FOR ANTIRADICAL AND ANTIFUNGL ACTIVITY

Nasser A. Awadh Ali, *, Hassan A. Samaha, Norbert Arnold, Mehdi Alhaj, andLudger Wessjohann

Abstract

A total of fifty different extracts from eighteen endemic Soqotran medicinal plants belonging to twelve plant families were screened for their antioxidant activity, using the DPPH free radical scavenger assay and their antiphytofungal activity against the phytopathogenic fungus Cladosporium cucumerinum, using a microbioassay on TLC plates. Of the extracts tested, 8 out of 25 methanol extracts showed more than 50% antiradical activity at a concentration of 200 μg/ml. Extracts of Kalanchoe farinaceae, Caralluma socotrana, and Boswellia socotrana were the most active ones. Nine out of fifty extracts exhibited antifungal activity. Chloroform extracts of Pulicaria stephanocarpa leaves and roots showed at concentration of 400μg inhibition zones of 20 and 18 mm, respectively. The chloroform extract of Kalanchoe farinaceae leaves exhibited stronger antifungal activity (18 mm inhibition zone) than the methanolic extract (15 mm inhibition zone). The most active methanolic extract was obtained from Acridocarpus socotranus leaves with 18 mm inhibition zone for 400 μg applied.

Keywords: Plant extracts; Antioxidant; Antifungal; Cladosporium cucumerinum; Soqotra.