Abstract: The antioxidant activity of anthocyanins from Morus nigra L. (AMNL) in vitro was determined and compared with that of anthocyanins from Morus alba L. (AMAL) and Morus alba Linn. var. tatarica. (AMALV). The antioxidant evaluation was performed by 1,1-diphenyl-2-picryl-hydrazyl (DPPH), superoxide anion, hydroxyl and alkyl free radical scavenging assays and total antioxidant capacity (TOA) assay using rutin and VC as controls. The results showed that AMNL had stronger scavenging effect on DPPH free radicals with IC50 of 9.07 mg/L than AMAL and AMALV, but weaker scavenging effect on DPPH free radicals than rutin and vitamin C. Similarly, AMNL had more powerful scavenging effect on superoxide anion free radicals with IC50 of 2.82 mg/L and hydroxyl free radicals with IC50 of 7.77 mg/L than AMAL, AMALV, rutin and VC. However, anthocyanins from all the three cultivars of mulberry had a scavenging rate of less than 50% against alkyl free radicals. The total antioxidant capacity of AMNL revealed 11.8-, 2.6- and 1.3-fold enhancement when compared with AMAL, AMALV and rutin, but was lower than that of vitamin C.

Key words: Morus nigra L., anthocyanins, antioxidation in vitro, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay