Antioxidant activity and phytochemical composition of aqueous extract of markhamia lutea (Benth) K. Schum. leaves

Abstract

In the present study Markhamia lutea (Benth) K. Schum., a Bignoniaceae member was evaluated for its physicochemical properties, phytochemical constituents and antioxidant activity with a view to develop a herbal drug for treating / preventing oxidative stress mediated diseases. Physicochemical properties (total ash, acid soluble ash, water soluble ash and extractive values) and mineral composition were analyzed in the leaf material of M. lutea. Aqueous extract was prepared and its phytochemical profiles were screened and presence of flavonoids was identified through LC-MS/MS analysis. Further, antioxidant activity was evaluated using in vitro assays like ferric reducing power, phosphomolybdate reducing power, radical scavenging against DPPH, superoxide and hydrogen peroxide. Results of physicochemical analysis and phytochemical screening revealed total ash (8.88%), acid soluble ash (0.05%) and water soluble ash (1.36%) contents and extractive values (1.88-3.16%), calcium (80.4%), potassium (10.7%) and iron (1.5%). Phytochemical screening revealed that the aqueous extract contains alkaloids, flavonoids, phenolic compounds, glycosides and carbohydrates. LC-ESI-MS/MS analysis revealed the presence of flavonoids such as rutin, pectolinarin, chrysoeriol, curcumin, kaempferol-3-glucoside-3-rhamnoside, isorhamnetin-3-galactoside-6-rhamnoside and 3-hydroxy-3,4-dimethoxy flavones in the aqueous extract. Aqueous extract showed dose-dependent ferric reducing power (1.03 Abs at 700 nm) and phosphomolybdate reducing power (270 Ascorbic acid equivalent antioxidant activity) at a concentration of 1 mg/ml. It also showed maximum level of scavenging of DPPH (71.27%) followed by hydrogen peroxide (55.09%) and superoxide radicals (43.66%). M. lutea leaf could be explored as a potential source of antioxidant compounds to prevent various oxidative stress-induced diseases.