PHYTOCHEMICAL ANALYSIS, TOXICITY AND ANTIBACTERIAL ACTIVITY OF BENIN MEDICINAL PLANTS EXTRACTS USED IN THE TREATMENT OF SEXUALLY TRANSMITTED INFECTIONS ASSOCIATED WITH HIV/AIDS

Abstract

Phytochemical screening of thirteen medicinal plants used in the treatment of sexually transmitted infections (STI), HIV/AIDS in Benin, showed that mucilage, gallic tannins and anthocyanins were the most common chemical groups. Water-ethanol (HE): 4/6 v/v, aqueous (A) and dichloromethane (DCM) extracts were prepared for each plant and tested for toxicity against shrimp larvae (Artemia salina Leach). Twenty two extracts were found not toxic (LC50 ≥ 0.1 mg / mL) with A13 aqueous extract of Vitex doniana Sweet (LC 50 = 1.35 mg / mL) as the most selective one. Antibacterial tests of extracts showed bacteriostatic activity on both strains tested (E. coli ATCC 25922 and S. aureus ATCC 25923) with the minimum inhibitory concentrations (MIC) ranging from 0.625 mg / mL to 5 mg/mL on E. coli and 0.078 to 1.25 mg/ml on S. aureus. Only the hydroethanolic extract of Acanthospermum hispidum (HE7) showed bactericidal activity against both strains with minimum bactericidal concentrations (MBC) values of 2.5 mg/mL and 0.625 mg/mL on E. coli ATCC 25922 and S. aureus ATCC 25923 respectively, while the hydro ethanolic extracts of Ocimum gratissimum (HE3), Caesalpinia bonduc (HE9) and Calotropis procera (HE10) were active against S. aureus ATCC 25923 with MBC values of 0.3125 mg/mL, 0.625 mg/mL and 1.25 mg/mL, respectively.