Evaluation of the Antibacterial and Antidiarrhoeal Activities of Heeria Insignis O. Ktze
Heeria insignis O. Ktze (Anacardiaceae) is an indigenous African shrub used in treatment of diarrhea, venereal diseases, tapeworm, hookworm, schistosomiasis, kidney trouble and for increasing lactation in women after childbirth. The methanol and dichloromethane extracts of the leaves were evaluated for antibacterial activity (using agar-diffusion method) and antidairrheal activity (using isolated rabbit jejunum and castor-oil induced diarrhea in mice). The methanol extract gave higher antibacterial activity than dichloromethane. The order of susceptibility of test microorganisms to methanol extract were Salmonella typhi>Pseudomous aeruginosa> Staphylococcus aureus>Bacillus subtilis>Escherichia coli which were comparable to standard. The minimum inhibitory concentration of the methanol extract for these microorganisms was also determined. The minimum inhibitory concentration (mg/ml) of methanol extract against microorganisms is; B. subtilis (3.9), S. aureus (1.95), E. coli (62.5), Ps. aeruginosa (3.9) and S. typhi (1.95). On the isolated rabbit jejunum evaluation, both extracts produced concentration-dependent relation of isolated rabbit jejunum that was not blocked by phentolamine, suggesting that extracts act via mechanisms other than alpha-adrenergic receptor. In the castor oil-induced diarrheoeal test, each extract gave 80% protection at 200 mg/kg, which is comparable to loperamide 2 mg/kg with 80% protection. This finding may explain the use of the plant in diarrhea and bacterial diseases.