Antimicrobial, antioxidant and cytotoxic activities of selected medicinal plants from Yemen

Ninety crude extracts, including dichloromethanic, methanolic and aqueous extracts from 30 plants used in Yemeni ethnomedicine to treat common infections, were screened in vitro for antibacterial, antifungal, antioxidant and cytotoxic activities.

Three Gram-positive bacteria and two Gram-negative bacteria, Candida maltosa and 5 opportunistic human pathogenic fungi (2 yeasts, 3 hyphomycetes) have been used as test organisms. Extracts of Acacia nilotica (L.) Del., A. tortilis (Forsk.) Hayne, Commiphora foliacea Dhotar W, Ficus vasta Forsk., Ocimum forskolei Benth., Plicosephalus curviflorus, Salvadora persica, Sansevieria aff. ehrenbergii, Solanum nigrum L. and Tamarindus indica L. showed antibacterial activities against at least four bacterial strains with methanolic extract of Tamarindus indica flowers being the most active, followed by the methanolic extract of the fruits from Ficus vasta.

Of the 30 plants tested, thirteen showed antifungal activity. Methanolic extracts of Azima tetracantha Lam. and Solanum incanum L. inhibited the growth of all tested pathogenic fungi.

In the DPPH assay extracts from 10 plants showed activities comparable to those of ascorbic acid. The highest antioxidative activities could be found in the methanolic extracts of Acacia nilotica leaves and Tamarindus indica fruits.

The extracts of 5 plants, e.g. Plicosephalus curviflorus and Commiphora kua, exhibited remarkable cytotoxic activities against cultivated FL cells.

The results confirm the great potential of ethnomedicinal plants from the Arabian region and are useful for rationalizing the use of medicinal plants in primary health care in Yemen.

Acknowledgements: The authors would like to thank Deutscher Akademischer Austauschdienst (DAAD) for a grant enabling the stay of Dr. Al-Fatimi at Ernst-Moritz–Arndt University Greifswald, that was used to carry out this research.