Total phenolic and flavonoid contents, antioxidative and anti-tyrosinase activity of Dipterocarpus alatus bark extracts

Abstract

“Yang-Na” (Dipterocarpus alatus) is a tree with a wide range of beneficial utilization, in particularly alternative energy area. Beside this, the bark part is of interest as a major deposited source of secondary metabolites that potentially have beneficial biofunctions, yet the limit of related scientific evidence is encountered. Therefore, to establish the supporting evidence for rationale utilization thereof, this research investigated the phytochemical contents and biological effects including determination of total phenolics and flavonoids, antioxidative (using DPPH and TBARS assays) and anti-tyrosinase activity in methanolic crude extract of Yang-Na bark (YNBE) using in vitro models. The results showed that YNBE highly contained phenolics with contents of 179.94 ± 0.45 mg GAE/g extract, while, the flavonoid contents was low as 2.64 ± 0.86 mg QE/g extract. Significantly, the good antioxidative and anti-tyrosinase effects were detected with concentration-dependent manner and IC₅₀ of 42.98 ± 0.62 µg/mL in DPPH assay and of 36.63 µg/mL for anti-tyrosinase activity, respectively. This data evidenced the potential in developing and utilizing of the YNBE as an alternative cosmeceutical agent.