Muellerilactone and other bioactive constituents of Phyllanthus muellerianus (kuntze) exell

A new friedelane triterpenoid 3-α-hydroxy-D:A-friedo-oleanan-27,16α-lactone (Muellerilactone) together with sixteen previously reported compounds were isolated and characterized from the ethanol extract of the leaves of the medicinal plant Phyllanthus muellerianus. Their structures were elucidated by means of spectroscopic and spectrometric methods as well as by comparison to the data available in the literature. Compounds 1, 2, 6, 12, 13, 14, and 15 are herein isolated for the first time from the genus Phyllanthus. Furthermore, the antioxidant and antimicrobial activities of some isolated compounds as well as the crude ethanol extract and fractions were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging potential and ferric reducing antioxidant power (FRAP) for antioxidant activity and microdilution method for antimicrobial potential. Compounds 11, 15 and 16 and the n-butanol fraction showed the highest antioxidant activity as judged by the DPPH scavenging assay and Ferric reducing antioxidant power. Compound 16 showed a moderate antimicrobial activity against Candida glabrata with a MIC value of 16 μg/mL.