Chimie médicale

Anti-infective Properties and Time-Kill Kinetics of Phyllanthus muellerianus and its Major Constituent, Geraniin

Abstract

Yaw Duah Boakye, Christian Agyare and Andreas Hensel

Microbial resistance to existing antimicrobial agents remains a global challenge. In recent years, there has been a significant upsurge in the search for newer antimicrobial agents from nature with plants becoming the major focus in most parts of the world due to the vast availability of plants, which have not been screened for their antimicrobial activity. Hence, the study investigates the antimicrobial properties of aqueous aerial part extract of Phyllanthus muellerianus (PLE) and its major constituent, geraniin. The agar well diffusion and micro-dilution methods as well as time-kill kinetic studies were used to determine the antimicrobial activity of PLE and geraniin against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Bacillus subtilis NCTC 10073, Streptococcus pyogenes (clinical isolate) and Candida albicans (clinical isolate). The mean zones of growth inhibition for PLE and geraniin were in the range of 12.0 ± 0.0 to 22.7 ± 0.3 and 12.0 ± 0.0 to 21.6 ± 0.3 mm, respectively. MIC of both PLE and geraniin ranged from 0.31 to 5 and 0.08 to 1.25 mg/mL (90 to 1310 μM), respectively whiles the minimum cidal concentrations were 5.0 to 50.0 and 2.5 to 10 mg/mL (2.62 to 10.5 mM), respectively. The time-kill kinetics study showed that PLE and geraniin may act as microbiostatic agents. Preliminary phytochemical screening of PLE showed the presence of alkaloids, glycosides, saponins, tannins, flavonoids and terpenoids. The observed antimicrobial activity of the extract, PLE, may be due in large proportion to its major constituent, geraniin.