Total phenolic contents and bioactivities of defatted Vitellaria paradoxa kernels from different origin

Total phenolic contents, antioxidant, cytotoxic and Epstein-Barr virus early antigen(EBV-EA)inhibitory activities of twenty-six methanol extracts from defatted Vitellaria paradoxa kernel at different sites were investigated. Furthermore, the correlation between total phenolic contents and bioactivities was discussed. The total phenolic contents were determined spectrometrically and antioxidant activities were evaluated by 1, 1-diphenyl-2-picrylhydrazyl(DPPH), 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid(ABTS)radical scavenging activity and ferric-reducing antioxidant power(FRAP)methods. The cytotoxic activities against human leukemia HL60 cells, lung cancer A549 cells and breast cancer SK-BR-3 cells were assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide(MTT)assay and the inhibitory effect on EBV-EA was assayed by the indirect immunofluorescence technique. Results showed that the total phenolic contents of twenty-six methanol extracts were different(25. 8 - 265. 7 mg GAE/g DW). In addition, some of the extracts had potent antioxidant activities(DPPH: IC₅₀ 3. 4 - 54. 9 μg/mL, ABTS: 1. 11- 4. 09 mmol TE/g, FRAP: 1. 24 - 1. 93 mmol TE/g), toxicities against one or more of HL60, A549 and SK-BR-3 cells(IC₅₀ 25. 1- 95. 5 μg/mL)and inhibitory effect on EBV-EA(85. 8%- 94. 9% at 100 μg/mL). A significant correlation was observed between total phenolic contents and antioxidant activities(r=0. 750-0. 837, P< 0. 01).