Comparative Study of Antimicrobial and Toxic Activities of Seven Medicinal Plants of the Beninese Flora

Abstract

Medicinal plants are endowed important pharmacological properties. Through their broad spectrum of biological activities, people use them for their primary health needs. Uncontrolled use can cause complications for these users. Thus, a study of the antimicrobial activities of pathogenic bacteria in humans would help to elucidate in part the field of action of the plants studied. Our works aims to make a comparative study of antimicrobial and toxic activities of essential oils and dichloromethane extracts. The Results of phytochemical screening tests of dichloromethane extracts show that they are rich in secondary metabolites. Evaluation of antimicrobial activities of essential oils and dichloromethane extracts showed activity against eleven strains tested, with MIC values ranging from 0.312 to 5.00 mg/mL. Dichloromethane extracts have a more interesting inhibitory activity than their essential oils except for essential oils of C. citratus and C. aurantifolia which exhibit a better inhibitory activity on all the bacteria tested compared to their dichloromethane extracts, except C. aurantifolia, Which has better inhibitory activity on M. luteus (20 mm) for its dichloromethane extract than its essential oil. Similarly for essential oils from E. camaldulensis on P. mirabilus (20.5 mm), C. schoenantus on P. aeruginosa (20.5 mm) and S. aureus (16.75 mm) and P. guajava on S. aureus (19.75 mm) which exhibit better inhibitory activity compared to dichloromethane extracts. Evaluation of larval toxicity, it follows that the essential oils studied are less toxic than campthotecin, the reference compound. Dichloromethane extracts are less toxic than their corresponding essential oils.