Evaluating eggplant (Solanum melongena L) genotypes for bioactive properties: A chemometric approach

Thirty four genotypes of eggplant and its wild relatives were evaluated for their total phenolics, flavonoid content and antioxidant capacity. Free radical scavenging was evaluated using four in-vitro assays, viz. FRAP (Ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), TEAC (Trolox equivalent antioxidant capacity) and DPPH (2, 2-diphenylpicrylhydrazyl). Total phenolics in eggplant showed a wide variation, ranging from 22.62 to 234.46 mg gallic acid equivalents (GAE)/100 g fw (244.28 to 2990.64 mg GAE/100 g dw). With the exception of Solanum aethiopicum and its accessions (Ac-1, Ac-2 and Ac-3), all wild relatives had significantly (p < 0.05) higher total phenolics and flavonoid content than cultivated ones. Total antioxidant capacity (FRAP) in wild genotypes ranged from 1.13 to 8.04 μmol Trolox (TE)/g. The hierarchy in decreasing order was Solanum khasianum > Solanum torvum > Solanum sisymbriifolium > Solanum incanum > Solanum integrifolium > S. aethiopicum. The antioxidant capacity correlated high with total phenolics in all assays. In cultivated group, JBR-99 and RCMBL-3 possessed high antioxidant capacity than the rest. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) revealed distinct similarity between JBR-99 (green), S. sisymbriifolium, S. khasianum and S. torvum. Overall results indicate that the wild species of S. torvum, S. incanum and S. sisymbriifolium are potential candidates for improving the functional quality of cultivated eggplant.