α-Solasonine and α-Solamargine Contents of Gboma (Solanum macrocarpon L.) and Scarlet (Solanum aethiopicum L.) Eggplants

Abstract

The gboma (Solanum macrocarpon L.) and scarlet eggplants (Solanum aethiopicum L.), which form part of the traditional sub-Saharan African culture, are two of the many neglected crops with potential for increased cultivation or as a genetic resource for improving agronomic traits of the common eggplant. This work is focused on the analysis of glycoalkaloid levels in S. macrocarpon and S. aethiopicum to assess their safety. Liquid chromatography-mass spectrometry was used to quantify glycoalkaloids in S. macrocarpon and S. aethiopicum compared to Solanum melongena L. Fruits of S. aethiopicum and S. melongena contained 0.58-4.56 mg/100 g of alpha-solamargine and 0.17-1 mg/100 g of alpha-solasonine, on a wet basis. S. macrocarpon fruits had much higher values of alpha-solamargine (124-197 mg/100 g) and alpha-solasonine (16-23 mg/100 g). However, the proportions of alpha-solamargine and alpha-solasonine of S. melongena and S. macrocarpon were similar (76-89% of alpha-solamargine), whereas in S. aethiopicum fruit composition was more variable (48-89% of alpha-solamargine). According to these results, the glycoalkaloid levels of S. macrocarpon fruits are 5-10 times higher than the value considered to be safe in foods and might not be considered suitable for human consumption; however, the glycoalkaloid levels of S. aethiopicum were similar to those of S. melongena (about 14% of values considered as toxic) and could be considered as safe for consumption. The incorporation of the cultivated African S. aethiopicum into eggplant breeding programs to develop improved varieties of the common eggplant may represent an alternative to crossing with wild species.