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

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.