Functional constituents and antioxidant activities of eight Chinese native goji genotypes.

We quantified the levels of polyphenols, carotenoids and polysaccharides in fruits of the eight Chinese native goji genotypes, antioxidant activities of these fruit extracts were also evaluated by DPPH, ABTS and FRAP methods. Quercetin-rhamno-di-hexoside (435-1065 μg/g) and quercetin-3-O-rutinoside (159-629 μg/g) were found to be the predominant flavonoids. Chlorogenic acid was the most abundant phenolic acid (113-526 μg/g), while zeaxanthin (17-9306 μg/g) was the major carotenoid. The total antioxidant activities (TAA) of the berry extracts were significantly correlated with the total polysaccharide and phenolic contents, but not with total carotenoid (TC) levels. Overall, fruits of the Ningxia goji (Lycium barbarum L.) genotypes, DM (Damaye), NJ1 (Ningji No.1), BH (Baihua) and NH (Ningxiahuangguo) were not only rich in polyphenols, carotenoids and polysaccharides, but had significantly higher TAA than those of the other genotypes, suggesting that they represent an excellent source of antioxidants for human nutrition.