Integrative Pharmacognosy of Phytosterols from Nigerian Dietary Medicinal Plants as Adjunctive Therapy in Prostate Health: Bioavailability, Mechanism, and Clinical Pilot

Benign prostatic hyperplasia (BPH) and prostate cancer are significant health burdens among Nigerian men above 50 years, with incidence rising across the South West and South South zones. Phytosterols, particularly beta-sitosterol and campesterol from Nigerian dietary and medicinal plants, have been proposed as adjunctive agents for prostate health due to their 5-alpha-reductase and anti-inflammatory properties. However, oral bioavailability of phytosterols is inherently poor, and clinical evidence in Nigerian patient populations is absent. This PhD research employs an integrative pharmacognosy approach combining phytosterol profiling, bioavailability enhancement formulation, mechanistic in vitro evaluation, and a clinical pilot study in Nigerian BPH patients. Phytosterol profiling by GC-MS was performed across ten Nigerian dietary medicinal plants including Irvingia gabonensis, Sesamum indicum, and Cucurbita pepo seeds. Beta-sitosterol and campesterol were the dominant phytosterols across all sources. A novel microemulsion-based delivery system was formulated to enhance phytosterol bioavailability, characterised by particle size, encapsulation efficiency, and in vitro intestinal permeability using Caco-2 cell monolayers. Mechanistic in vitro studies in LNCaP and RWPE-1 prostate cell lines assessed 5-alpha-reductase inhibition, androgen receptor modulation, NF-kB pathway suppression, and apoptotic induction. A 12-week randomised double-blind pilot study in 60 BPH patients at University of Benin Teaching Hospital evaluated PSA level change, IPSS symptom score, maximum urinary flow rate, and prostate volume as primary outcomes. The microemulsion formulation demonstrated 3.2-fold improved permeability over crystalline phytosterol. Significant IPSS score improvement and maximal flow rate increase were observed in the treatment arm. These findings position Nigerian plant-derived phytosterols as viable adjunctive BPH therapies. Keywords: phytosterols, benign prostatic hyperplasia, bioavailability, 5-alpha-reductase, beta-sitosterol