Flavonoids Analysis Using HPLC of Ethanol and Chloroform Fractions of Alstonia Scholaris (R. Br) Bark and Their Antioxidant Potency

Alstonia scholaris R.Br is one of the medicinal forest plant in Indonesia. Antioxidant activity was considered to be correlated with atherosclerosis by LDL oxidation inhibition. Alstonia scholaris R.Br bark has been reported as potential antioxidant because of its alkaloid content, however the potency of its flavonoid as antioxidant has not been investigated. The research objective was to investigated the antioxidant activity, and to identify flavonoid compounds from Alstonia scholaris R Br in both ethanol, and chloroform fractions. Crude extract ethanol 70% of Alstonia scholaris bark, was fractionated by liquid-liquid fractionation using n-hexane, chloroform and ethanol. Ethanol, and chloroform fraction were analyzed for antioxidant activity through radical scavenge DPPH method, while identification of flavonoids was investigated by HPLC method. Results showed that yield of ethanol fraction was higher (2.52%) than that of chloroform fraction (0.83%) respectively.Ethanol fraction had stronger antioxidant activity with IC50 value 73.53 µg/mL than that of chloroform fraction (445.96 µg/mL) respectively. Identification of flavonoids through HPLC showed that ethanol fraction contain rutin (5,0112 mg/g), and quercetin (0.0470 mg/g) higher than that in chloroform fraction with rutin content (0.9358 mg/g) and quercetin (0.0376 mg/g). Rutin is dominant in both fractions, and rutin in ethanol fraction was higher than that in ethanol fraction. Quercetin, and rutin are flavonoid compounds act as antioxidants