Phytochemical Characterization of Solanum Scabrum Berries for Agricultural Waste Rediscovery in Sub-Saharan Africa

Solanum scabrum is an economically important crop in sub-Saharan Africa whose leaves are consumed as a popular leafy vegetable. The prolific blueberry-like berries, however, are generally discarded without consumption due to perceptual toxicity and remain a neglected agricultural resource. In order to re-evaluate consumption potential and facilitate new application of the untapped berry resource, this study aimed to systematically study berry phytochemicals of relevant importance. In this work, S. scabrum from eight different genetic sources were planted in Rutgers research farms and berries of different maturity were manually collected. The berry extract was then prepared and analyzed using high performance liquid chromatography coupled with ion trap mass spectrometry. A total of fifty-four phytochemicals were identified including those of nutritional value including chlorogenic acid and its isomers, flavonol glycosides of quercetin and isorhamnetin, largely acylated anthocyanins of petunidin, delphinidin and malvidin, saponins of diosgenin and tigogenin, and toxicity-responsible metabolites including a wide range of glycoalkaloids of solasodine and uncommon hydroxylated and methylated and/or methoxylated counterparts. Significant variance in phytochemical profile was noted across mature berries from different genetic sources and across different maturation stages of the same genetic variety. Despite the conventional toxic label, mature berries of certain genetic varieties were characterized with sufficiently low content of toxic glycoalkaloids and high level of polyphenols and evaluated to be both safe and nutritious for consumption. Such varieties could be introduced to sub-Saharan area as native “new” crops whose both leaves and prolific fruits are edible for additional food supply to combat against hunger. While for berries especially immature ones truly toxic with high levels of glycoalkaloids, these toxic metabolites would be easily extracted using acidified water and used for development of glycoalkaloid-based natural antimicrobial reagents or for steroidal drug synthesis in pharmaceutical industry.