Phytochemical Screening, In-vitro Antioxidant and Cytotoxic potentials of Brachychiton rupestris Leaves

Few studies had been conducted on the phytochemical profile and the biological activities of Brachychiton rupestris. The antioxidant activity of 85% methanolic extract of B. rupestris leaves and its derived fractions was assessed using five different in-vitro assays which are DPPH• assay, phosphomolybdenum assay (TAC), hydroxyl radical (•OH) scavenging assay, nitric oxide radical (NO•) scavenging assay and permanganate reducing antioxidant capacity (PRAC). The total phenolic, flavonoid and flavonol contents were also determined for the different plant samples using Folin-Ciocalteu, aluminum chloride and aluminum chloride/ sodium acetate methods, respectively. In-vitro cytotoxic activity of the crude extract and its fractions against HepG2 cell line was also evaluated via SRB assay. The ethyl acetate fraction obtained from the aqueous methanolic extract of the plant leaves possessed the most potent antioxidant potential according to the different applied assays (DPPH• SC50 = 25.50±0.76 µg/mL, TAC= 311.98±1.19 mg AAE/g ext., •OH SA= 68.42±0.15%, NO• SA= 33.68±1.98% & PRAC = 62.88±0.27%). It also owed the highest amount of phenolics (TPC= 342.10±2.08 mg GAE/ g ext.) whose majority were flavonoids (TFC= 309.82±3.64 mg QE/ g ext.). A strong positive correlation was found between the total phenolic contents of various plant samples and their antioxidant activity. The butanol derived fraction exhibited the most potent cytotoxic activity (IC50 = 8.60 µg/mL). To the best of our knowledge, it is the first study reporting the antioxidant and the cytotoxic activities of B. rupestris leaves. The study revealed that the B. rupestris leaves could be a good source of natural antioxidants which may be applied in food and pharmaceutical industries. They could also be a new opportunity of discovering anti-mutagenic agents.