In Vitro Pharmacological Evaluation of the Leaves and Stem Bark Extracts of Beilschmiedia penangiana Gamble

Abstract

The leaves and stem bark extracts of B. penangiana were screened to evaluate their antioxidant, antimicrobial, tyrosinase, lipoxygenase, and acetylcholinesterase activities. Evaluation of antioxidant activities were tested against DPPH, ABTS, and total phenolic content (TPC) assays. The antimicrobial activity were investigated by microdilution method for determination of MIC, MBC, and MFC. Tyrosinase and lipoxygenase inhibitory activities were analysed using mushroom tyrosinase and lipoxygenase enzymes, respectively. In addition, the acetylcholinesterase activity was tested using cholinesterase enzyme. The methanol extract of stem bark showed the highest phenolic content (176.8 mg GAE/g), DPPH free radical scavenging (IC50 95.5 μg/mL), ABTS (IC50 124.8 μg/mL), and lipoxygenase inhibitory activity (I: 46.3%). All extracts showed from moderate to weak activity with MIC/MBC/MFC values in the ranged of 62.5-1000 µg/mL. The ethyl acetate stem bark extract revealed the highest percentage inhibition on tyrosinase activity (I: 83.2%), while for acetylcholinesterase activity showed by the methanol leaves extract with percentage inhibition of 69.4%. The results revealed that the extracts of B. penangiana possessed significant activities on various biological studies. Further investigations will be focussing on isolation of the secondary metabolites responsible for the bioactivities.