Abstract: In order to explore their polyphenolic content and antioxidant activity, polyphenolics were extracted from pruned branches of seven varieties of wild spine grape trees in winter collected from a resource garden in Jiangxi province by ultrasonic-assisted organic solvent extraction technique. The contents of total phenols, total flavonoids and proanthocyanidins in crude extracts obtained from these materials were determined. Meanwhile, the crude extracts were analyzed for in vitro DPPH radical scavenging capacity, hydroxyl radical scavenging capacity, cupric reducing power and total reducing power and correlation analysis of these antioxidant properties was carried out. The results revealed that the contents of total phenols, total flavonoids and proanthocyanidins in wild spine grape branches were in the range of 24.68—32.76, 51.03—72.63, and 36.69—44.41 mg per gram of dried sample, respectively. Dried wild spine grape branches from seven varieties ranged from 23.62 to 28.02 mg/g in DPPH radical-scavenging capacity, from 31.51% to 36.11% in hydroxyl radical-scavenging capacity, from 47.19 to 73.28 mg/g in cupric reducing power, and from 39.76 to 53.80 mg/g in total reducing power. Thus, wild spine grape branches are rich in phenolics and have a strong antioxidant effect. Furthermore, a high correlation of reducing power with the contents of total phenols, total flavonoids and proanthocyanidins was observed (R2 ＞ 0.9). In conclusion, wild spine grape branches can provide a promising base material for natural antioxidants and biopharmaceuticals.

Key words: Vitis davidii Foex., grapevine cane, polyphenol, flavonols, proanthocyanidin, antioxidant activity