Intra-Specific Flavonoid Classes, Content and Relationships in African Yam Bean (Sphenostylis stenocarpa [Hochst ex A. Richmond] Harms] Tubers

Abstract

Background and Objective: Tubers of African yam bean [Sphenostylis stenocarpa (Hochst. ex A. Richmond) Harms], family Fabaceae, are under-exploited, especially in West Africa by humans. The tuber holds varying quantitative bioactive properties. The present study seeks to unveil inherent flavonoid compounds in different accessions of African yam bean (AYB) tubers. Materials and Methods: Fresh tubers were obtained from 17 accessions of AYB. The same was dried and flour samples were prepared. Flour samples from the 17 accessions were analyzed and 38 flavonoid compounds were obtained for each using High-Performance Liquid Chromatography (HPLC). Results: The 17 accessions differed in the proportion of the 38 flavonoid compounds. Flavonoid compounds with >1.0 g/100 g in the study were: Apigenin, didymin, daidzein, luteolin and isorharmmetic. The 38 flavonoid compounds were grouped into six sub-classes, 55% were flavones and anthocyanidin which had anthocyanin as the only member in the group, had the lowest (1%) component in the tubers of AYB. Conclusion: Variation in flavonoid content in AYB tuber is a function of the genotypes. Mean content is higher than most tuberous crops. The AYB tuber therefore promises to be an important industrial product for health benefits and promotion.