Some pharmacological properties of extracts of Terminalia sericea roots

Terminalia sericea Burch. Ex. DC (Combretaceae) extracts are used to treat bacterial infections, diarrhea, and diabetes. Intermediate and polar extracts of the roots exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus anthracis, and Pseudomonas aeruginosa, while the petroleum ether extract was inactive. The extracts were mildly active against Bacillus anthracis and Pseudomonas aeruginosa but exhibited the highest activity against Staphylococcus aureus. They also exhibited antifungal activity against Candida albicans and Aspergillus niger. An 80% aqueous ethanol extract of the roots did not have any effect on blood glucose levels during an oral glucose tolerance test (OGTT), in mice (P > 0.05). With the exception of the dichloromethane and petroleum ether extracts, all the intermediate and polar extracts were toxic to brine shrimps giving LC50 (95% confidence intervals) values ranging from 5.4 (3.5-8.4) to 17.4 (11.4-26.5) μg/ml, while that of cyclophosphamide, a standard anticancer drug, was 16.3 (10.6-25.2) μg/ml. Further work is in progress to isolate and identify active compounds in the extracts.