TITLE:
Influence of Soil Physicochemical Properties on the Polyphenolic Composition, Nutritional Profile and Antioxidant Activity of Hibiscus sabdariffa (R72-1 Variety) Calyces Cultivated in the Oubri and Guiriko Regions of Burkina Faso
AUTHORS:
Abdoul Rasmane Sawadogo, Arouna Ganame, Constantin Manienou Dabire, Bily Nebie, Abdoulaye Yougoubo, Mohammad Ouedraogo, Siaka Sosso, Remy Bationo, Tatiafa Da, Momouni Ouedraogo, Kalifa Coulibaly, Aboubacar Toguyeni
KEYWORDS:
Hibiscus sabdariffa, Anthocyanins, Polyphenolic Constituents, Nutritional Potential
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.15 No.2,
May
14,
2026
ABSTRACT: The calyces of Hibiscus sabdariffa, predominantly produced in the Guiriko region of Burkina Faso, constitute a potential source of micronutrients owing to their high content of phenolic compounds. This study aimed to evaluate the influence of soil physicochemical characteristics on the polyphenolic composition and nutritional potential of calyx extracts from the R72-1 variety of Hibiscus sabdariffa cultivated in the Guiriko and Oubri regions of Burkina Faso. Soil samples collected from the Guiriko and Oubri regions were analyzed following the standardized BUNASOL procedures. Calyces’ extracts were prepared using acetone/water/acetic acid (70:29.5:0.5), methanol-HCl (99:1), and distilled water as solvents. Total phenolic compounds, flavonoids, anthocyanins, and tannins were quantified by spectrophotometric methods, whereas total proteins and sugars were determined by the Kjeldahl and phenol-sulfuric methods, respectively. Antioxidant activity was assessed using DPPH, ABTS, and FRAP methods. Chromatographic profiles of the extracts were established by HPTLC. The results suggest that calyces harvested from Guiriko soils, which showed higher measured nutrient contents and more favorable soil chemical properties (score 37.5 ± 0.5 versus 25.75 ± 0.0 for Oubri), tended to exhibit greater contents of total phenolics (72.69 ± 1.89 mg GAE/g), flavonoids (32.16 ± 1.95 mg QE/g), anthocyanins (25.48 ± 2.51 mg Cyd-3-glc eq/g), proteins (1.556% ± 0.312%), and sugars (40.82 ± 1.05 mg GE/g), the lowest levels of condensed tannins (0.198 ± 0.092 mg CE/g) and hydrolyzable tannins (0.278 ± 0.105 mg GAE/g), as well as stronger antioxidant activity (IC50 = 30.85 µg/ml), compared to calyces collected from Oubri soils. Conversely, six similar chromatographic bands were observed in calyces from both soil types, indicating that soil characteristics may influence anthocyanin content quantitatively rather than qualitatively. These findings highlight the nutritional and antioxidant potential of Hibiscus sabdariffa calyces and suggest that soil characteristics may help optimize their chemical and nutritional quality.