CASSIA SENNA (SENNA ALEXANDRINA) LEAVES AS A PROSPECTIVE SOURCE OF ANTI-ULCER THERAPEUTICS IN NIGERIA: An Ethnopharmacological, Phytochemical, and Drug Discovery Perspective

Peptic ulcer disease (PUD) continues to exert a substantial public health burden globally, with developing nations such as Nigeria experiencing heightened challenges due to high prevalence of Helicobacter pylori infection, widespread self-medication with non-steroidal anti-inflammatory drugs (NSAIDs), limited access to advanced diagnostics and therapeutics, and the rising tide of antimicrobial resistance. Current pharmacological interventions—proton pump inhibitors, H₂-receptor antagonists, and antibiotic eradication regimens—while effective in many cases, are plagued by issues of recurrence, adverse effects including long-term microbiome disruption and nutrient malabsorption, high costs, and incomplete eradication rates in resistant strains. These limitations underscore the urgent need for novel, affordable, multi-target therapeutic agents derived from indigenous medicinal resources. Cassia senna (Senna alexandrina Mill.), a shrub native to arid regions of Africa and widely naturalized or cultivated across the continent, has long been valued in traditional African medicine primarily for its potent laxative properties attributable to anthraquinone glycosides. However, a growing body of ethnobotanical, phytochemical, and pharmacological evidence suggests that its leaves harbor a broader spectrum of bioactive constituents—including flavonoids (notably kaempferol), phenolic compounds, tannins, and certain anthraquinones such as aloe-emodin, chrysophanol, and rhein—that exhibit significant antioxidant, anti-inflammatory, antimicrobial, and gastroprotective activities. These properties align mechanistically with key pathways implicated in ulcerogenesis and healing: mitigation of oxidative stress through enhancement of endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase), suppression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and enzymes (COX-2, 5-LOX), augmentation of gastric mucus secretion and mucosal blood flow, and potential direct inhibitory effects on H. pylori. This integrative review synthesizes available ethnopharmacological knowledge from Nigeria and broader sub-Saharan Africa, critically appraises the phytochemical profile and reported bioactivities (with particular attention to studies on related Senna species demonstrating anti-ulcer efficacy in ethanol- and NSAID-induced models), and evaluates toxicological considerations associated with chronic anthraquinone exposure. Building on identified gaps—most notably the paucity of direct, rigorous investigations specifically on Nigerian-sourced S. alexandrina for gastroprotection—we propose a pragmatic, resource-sensitive drug discovery pipeline tailored to the Nigerian context. This framework emphasizes bioassay-guided fractionation to isolate or enrich non-laxative, gastroprotective fractions; in vitro and in vivo validation using standardized ulcer models; toxicological profiling per OECD guidelines; and translational steps toward standardized herbal or semi-purified formulations suitable for NAFDAC registration and clinical evaluation. We conclude that S. alexandrina leaves represent a promising yet underexploited candidate for anti-ulcer drug development in Nigeria. Strategic investment in local phytochemical research capacity, sustainable cultivation, and public-private partnerships could transform this traditional resource into a source of affordable, culturally acceptable therapeutics, while contributing to broader goals of pharmaceutical self-sufficiency, biodiversity valorization, and improved gastrointestinal health outcomes across West Africa.