Characterization, quantification and antioxidant potential of phenolic compounds in Brachychiton rupestris (T.Mitch. ex Lindl.) K. Schum. leaves

The studies conducted to investigate the pharmacological potential or the chemical composition of Brachy chiton rupestris leaves were very limited. The present study aims to isolate, identify and quantify the major phenolics in B. rupestris leaves and to evaluate their antioxidant potential. Methanol (85.0%) extract of B. rupestris leaves was prepared and successively partitioned with petroleum ether, dichloromethane, ethylacetate and n-butanol, respectively. The bioactive compounds in the ethyl acetate and n-butanol fractions were separated chromatographically, and their structures were characterized. Their concentrations were determined using HPLC-DAD, and their antioxidant potential was evaluated against DPPH. Caffeic acid, p-coumaric acid, nicotiflorin, methyl gallate, isoquercetin, rutin, quercetin and kaempferol were the major phytochemicals. Methyl gallate exhibited the most potent antioxidant activity with an IC50 of 18.19 ± 0.161 µg/mL. B. rupestris could be considered a promising source of antioxidants which suggests its application in nutraceuticals and therapeutic formulations.