Antibacterial and Antiplasmodial Properties of Chemical Compounds Isolated from Bark of Phyllanthus acidus (L.) Skeels

Abstract

Phyllanthus acidus (L.) Skeels (Phyllanthaceae family) is a plant that is widely distributed in Asian countries, which is traditionally used as a medicinal plant to treat various ailments. Inspired by the uses of the plant, the aim of this study was to extract and isolate bioactive compounds from P. acidus as potential antimicrobials. The isolation and identification of phyllanthol (1) and meso-hydrobenzoin (2) from the dichloromethane bark extract of P. acidus are presented. The structures of these compounds were elucidated by extensive spectroscopic analyses. To the best of our knowledge, compound 1 is a known compound and compound 2 is the first report presented on the isolation and structural elucidation as a natural compound. The bark extract and the isolated compounds were evaluated for antibacterial activities against Escherichia coli, Enterococcus faecium, Pseudomonas aeruginosa, and Staphylococcus aureus by disc diffusion assay, minimal inhibitory concentration (MIC), and half-maximal inhibitory concentration (IC50). Compounds 1 and 2 showed significant activities against Escherichia coli (IC50 value = 0.42 and 0.47 μg/mL, respectively), Enterococcus faecium (IC50 value = 0.86 and 0.43 μg/mL, respectively), Pseudomonas aeruginosa (IC50 value = 0.45 and 0.44 μg/mL, respectively), and Staphylococcus aureus (IC50 value = 12.87 and 0.44 μg/mL, respectively). These compounds also showed significant antiplasmodial activities towards the 3D7 strain with IC50 value of 0.218 μM for compound 1 and 0.228 μM for compound 2, in vitro. All the isolated compounds were not active against MRC-5 cells with an IC50 value of more than 60 μg/mL. From the results obtained, P. acidus has been proven as a source of molecules with therapeutic potentials.