Effect of solvents on polyphenol recovery and antioxidant activity of isolates of Asparagus Officinalis roots from Chinese and New Zealand cultivars

Summary Nine solvents of varying polarity (water, methanol, ethanol, isopropyl alcohol, acetone, n‐butyl alcohol, ethyl acetate, chloroform and petroleum ether) were used to determine the optimal extraction solvent that gives the highest yield of bioactive compounds from six Asparagus Officinalis L root (AR) cultivars from China and New Zealand. The contents of total phenolics (TPC), total flavonoids (TFC), total saponins (TSC) and caffeic acid (CA) were determined. Antioxidant assessments included ferric reducing/antioxidant power (FRAP), 2, 2′‐azinobis‐(3‐ diphenyl‐ethylbenzothiazoline‐6‐sulphonic acid) radical cation (ABTS) and β‐carotene bleaching activity assays. The results indicated that yellow AR from China had the highest content of TPC, TFC, TSC and CA compared to other AR cultivars. The most effective solvents for bioactive compound recoveries and antioxidant activities from A. officinalis L root extraction were ethanol and methanol. The content of CA in ethanol extracts of yellow AR achieved 92.0 mg g−1 DE. Effect of extraction solvent on the antioxidant activities of asparagus root extracts.