Regional variability in phytochemical profiles and bioactivities of macerate and decoction extracts from three medicinal plants of Burkina Faso

---

Résumé

Introduction: Regional variability in secondary metabolite biosynthesis represents a critical dimension of plant chemodiversity. This study examined Acanthospermum hispidum, Vitex simplicifolia, and Vetiveria nigritana collected from three ecological zones of Burkina Faso (Centre-North, Centre, Cascades), focusing on phytochemical composition and bio activities.
Methods: Qualitative profiling of phenolic acids and flavonoids was performed by high-performance thin-layer chromatography (HPTLC). The solvent system consisted of ethyl acetate/formic acid/glacial acetic acid/water (100/11/11/26). The total phenolic content of plant extracts was determined using the Folin–Ciocalteu method. The flavonoid content was determined using the aluminum chloride colorimetric method. The biological potential of the extracts was evaluated using three biological assays: antioxidant activities (ABTS and FRAP), antiplasmodial activity, and antibacterial activity.
Results: Quantitative assays revealed pronounced differences in metabolite accumulation: V. simplicifolia leaves from the Centre region contained the highest polyphenol levels (450.21 ± 5.18 µg GAE/100 mg), while leaves from Cascades exhibited peak flavonoid content (269.43 ± 6.89 µg QE/100 mg). Antioxidant capacity varied accordingly, with A. hispidum leafy stems from Cascades showing strong ABTS activity (5.76 ± 0.32 µmol AAE/g) and V. simplicifolia bark from Centre-North displaying maximal FRAP reducing power (0.29 ± 0.004 µmol AAE/g). Bioactivity assays highlighted methanolic macerates of A. hispidum (Centre) with promising antiplasmodial activity (IC50 = 15.71 µg/mL), and V. nigritana rhizomes with potent bactericidal effects (MIC = 1.5–3 mg/mL; MBC/MIC ≤ 2). Principal Component Analysis (PCA) revealed three chemotypic clusters linking metabolite profiles to ecological origin: V. simplicifolia (Centre/Cascades) associated with antioxidant and antibacterial potency, A. hispidum (Centre) with antiplasmodial activity, and V. nigritana (Centre-North/Cascades) with antibacterial strength.
Discussion: These findings underscore the ecological modulation of secondary metabolism and highlight the importance of regional chemodiversity for phytomedicine standardization and biodiversity conservation

Mots-clés

antibacterial activity, antioxidant activity, antiplasmodial activity, ecological variability, medicinal plants, phenolics, plant chemodiversity, secondary metabolites