Chemical Constituents and Biological Functions of Different Extracts of Millettia speciosa Leaves

Millettia speciosa, a traditional Chinese folk medicine, used as immunity enhancer and anti-bronchitis. The study was proposed to investigate phytocomponents and pharmacological activities (antityrosinase, sunscreen and anticancer) of the different fractions of M. speciosa leaves. The sample was extracted with solvents of increasing polarity i.e. petroleum ether (PE), ethyl acetate (EtOAc), methanol (MeOH) and the total flavonoid content for each fraction was determined. The GC-MS analysis revealed various important bioactive compounds. The identified major compounds included beta sitosterol (12.039%), (Z)-9-octadecenamide (6.299%) and gamma sitosterol (4.910%). The highest flavonoid content was recorded for the PE extract i.e. 47.50 ± 0.40%. The PE extract showed significant antityrosinase activity (70.30 ± 0.90 %) with IC50 0.035 mg/ml followed by the MeOH extract i.e. 66.50 ± 1.20% with IC50 0.039 mg/ml. The highest sunscreen activity was noted for the EtOAc extract by observing maximum absorbance value (1.518 ± 0.49) in UVA region followed by 1.214 ± 0.46 in UVB zone. The highest cytotoxicity (29.45 ±1.17% viability) towards MCF-7 breast cancer cells line was noted for the PE extract with IC50 6.73 µg/ml. Overall, our study revealed the presence of potential bioactive compounds for each extract that exhibited significant therapeutic activities and therefore validate the importance of M. speciosa leaves as a source of natural medicine.