In vitro antibacterial, antioxidant, total phenolic contents and anti-HIV-1 reverse transcriptase activities of extracts of seven Phyllanthus sp

Phyllanthus species has long been used in folk medicine in many countries as antimicrobials and/or antioxidants. Eighty percent methanol extracts obtained from seven Phyllanthus sp. were evaluated for antibacterial activity using the broth micro-dilution assay, anti-HIV-1 reverse transcriptase (RT) activity using the HIV-RT assay, antiradical scavenging effects and phenolic contents using the DPPH assay and Folin–Ciocalteau colorimetric method, respectively. Best antibacterial activity as indicated by the minimum inhibitory concentration (MIC) values was obtained by Phyllanthus amarus against Staphylococcus aureus (Gram-positive) with a MIC value of 17.7 μg/ml. Phyllanthus myrtifolius and Phyllanthus urinaria inhibited growth of Pseudomonas stutzeri (Gram-negative) with MIC values of 78 μg/ml and 117 μg/ml, respectively. A strong inhibition of HIV-RT was obtained by Phyllanthus pulcher (IC50 5.9 μg/ml) followed by P. urinaria and P. myrtifolius (IC50 of 10.4 and 12.7 μg/ml, respectively). A remarkable DPPH scavenging effect was observed with P. myrtifolius, Phyllanthus reticulatus and P. urinaria (IC50 of 10.2, 10.8 and 17.4 μg/ml, respectively). Highest total phenolic contents were recorded for P. myrtifolius and P. urinaria (207 and 205 mg/GAE/g respectively). With the exception of P. amarus, Phyllantus debilis and P. pulcher, total phenolic contents correlated with DPPH radical scavenging activity. Our findings support the uses of the Phyllanthus species in traditional medicine. The interesting biological activities obtained by P. myrtifolius, P. urinaria and P. pulcher need to be further investigated to isolate active agents and to study their mechanism of action.