Extraction, quantification and antioxidant activities of flavonoids, polyphenols and pinitol from wild and cultivated Saraca asoca bark using RP-HPLC-PDA-RI method

Abstract

Saraca asoca (Roxb.) De Wilde Syn. Saraca indica Linn belonging to the family Leguminosae, is one of the ancient medicinal plant of India and its bark is used in Ayurvedic preparations. In the present work, the barks were collected from mature trees of different geographical locations. Besides, one of the best chemotype is cultivated under different fertilizer treatments and the barks from 4year old plants were taken up for analytical studies. The barks were extracted with methanol as well as aqueous-methanol solvent systems, and chemical compositions were compared using RP-HPLC-PDA-RI analysis. Different classes of compounds viz. pinitol, flavonols and polyphenols were detected through the analytical protocol developed by our laboratory. It was found that the barks collected from Uttar Pradesh (BLA, BLK), Sirsi, Karnataka (BSS) and Empress Garden, Pune (BEG) gave higher yield of the extracts and were more enriched with the above classes of compounds. For getting barks in a short period of time, the BSS plant saplings were experimentally cultivated under different fertilizer treatments. It was found that the plants treated with a combination of fertilizers such as poultry waste+biofertlizer, vermicompost+biofertlizer and farm yard manure+biofertlizer+diammonium phosphate yielded reasonably higher amounts of extracts, which were chemically close with the parent bark extracts. Among these treatments, the vermicompost+biofertlizer gave pinitol (729mg), flavonoids (2872mg) and polyphenols (1150mg) in 100g bark extracts. The antioxidant activities were evaluated by using 1,1-diphenyl-2-picrylhydrazyl radical-scavenging assay and interestingly it was noticed that the extracts contained improved percentage of flavonoids and pinitol showing better activity.