The in vitro antimicrobial activity of some Yemeni medicinal plants.
The ethanolic extracts (each at 80% concentration) of 27 plants, collected in spring 2002-03 from different areas of Yemen, were investigated for antibacterial (against Staphylococcus aureus, S. epidermidis, Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae) and antifungal (against Aspergillus flavus, Candida albicans and Fusarium solani) activities in vitro. These plants were Blepharis ciliaris, Aerva javanica, Achyranthes aspera, Hyphaene thebaica, Aristolochia bracteata, Conyza pyrrhopappas [Conyza pyrrhopappas], Guizotia scabra, Kleinia odora, Tamarindus indica, Alhagi maurorum, Prosopis cinnabari, Cadaba rotundifolia, Cleome amblyocarpa, Carica papaya, Momordica balsamina, Cyperus rotundus, Euclea balfouriana, Jatropha variegata, Nepeta deflersiana, Marrubium vulgare, Dorstenia foetida, Boerhavia repens, Rumex nervosus, Ruta chalepensis, Dodonaea viscosa, Tamaris aphylla and Ferula communis. Nineteen extracts (70.3%) showed marked activity against Staphylococcus aureus, 14 extracts (51%) against Candida albicans, and 10 extracts (37%) against Bacillus subtilis. The ethanolic extracts of P. cinnabari and Ruta chalepensis showed wide antimicrobial activity against the microorganisms (80% and 70%, respectively). This marked activity of the extracts verifies partially the use of these plants in traditional Yemeni medicine.