A comparative study on antioxidant and DNA protective activity of different skin coloured brinjal (Solanum melongena)

Abstract

The aim of this study was to investigate the in vitro antioxidant activity and DNA damage inhibition potential of aqueous extract of S. melongena with different skin colours. Water extracts of brinjal with four different skin colours: moderately purple (S1), light purple (S2), dark purple (S3) and purple with green lines (S4) were tested for their antioxidant and radical scavenging activities. The total phenolic content (TPC) was quantified using Folin-Ciocalteau’s method. The effectiveness of brinjal extracts in preventing radical induced DNA damage was also determined. There was a significant difference (p<0.0001) between the skin colour andantioxidant activity. Brinjal with S3skin colour showed the highest TPC and antioxidant activity measured by FRAP while, S2 showed the least. S1 displayed the highest percentage of DPPH radical scavenging activity with an IC50 value of 3.51±0.62 mg/ml while, S3 demonstrated the strongest total antioxidant capacity with an inhibition percentage of 40.45±1.17. In the FTC (Ferric Thiocyanate) and egg yolk model, S1 and S3 showed better antioxidantactivity than S2 and S4. The in vitro freeradical quenchingand antioxidant results well correlated with the in vitro lipid peroxidation assays. All extracts were able to effectively retain DNA against AAPH induced radical damage at the concentration levels (25 and 75 mg/ml) tested. All the extracts showed moderate to potent antioxidant activity, among which S3 and S1, intensely coloured skins, demonstrated better antioxidant activity which may be attributed to the higher phenolic content since a linear relation was observed between the TPC and the antioxidant parameters.