Antihypertensive Properties and Structural Analysis of Bioactive Peptides' Potential from Fermented African Yam Beans (Sphenostylis stenocarpa): A Review

Abstract

Hypertension represents a critical global health challenge, necessitating the development of safer, natural alternatives to synthetic inhibitors, which are often associated with adverse side effects. African yam bean (Sphenostylis stenocarpa) is an underutilized, high-protein legume (20%-29% crude protein) that serves as a sustainable reservoir for antihypertensive peptides. This review analyzes current advancements in the production, structural characterization, and mechanistic evaluation of these bioactive sequences. Traditional solid-state fermentation, primarily driven by proteolytic Bacillus species and lactic acid bacteria, effectively releases these peptides while significantly reducing antinutritional factors such as phytic acid and trypsin inhibitors. High-resolution analytical frameworks, including Reversed-Phase HPLC, MALDI-TOF MS, and tandem mass spectrometry (MS/MS), have identified that the most potent inhibitors are typically short sequences (< 3 kDa) characterized by hydrophobic or aromatic residues at the C-terminus. While specific amino acid sequences for African yam bean require further definitive identification, existing research has characterized highly active fractions that demonstrate dual ACE and renin inhibitory properties alongside significant antioxidant capacity. Furthermore, the presence of proline-rich motifs and hydrophobic residues within these peptides contributes to enhanced resistance against gastrointestinal proteolysis, although achieving optimal oral bioavailability remains a primary challenge for therapeutic translation. The integration of these bioactive peptides into functional food systems offers a culturally appropriate strategy for hypertension management in sub-Saharan Africa, provided future research utilizes high-resolution peptidomic profiling and standardized in vitro models to confirm their systemic efficacy. Comparative analyses of bioactive peptides from related legumes, including cowpea, soybean, mung bean, chickpea, and Bambara groundnut, are also presented to contextualize and predict the antihypertensive peptide profiles of African yam bean.