Influence of geographical location and environmental factors on the phytochemical composition, antioxidant activity, anti-inflammatory activity and antibacterial activity of the hydroethanolic extracts of Moringa oleifera lam. Seeds from three distinct regions of Algeria.

Abstract

The present study investigates the influence of geo-environmental heterogeneity on the phytochemical constitution and biological efficacy of the hydroethanolic extract of Moringa oleifera lam. seeds harvested from three climatically divergent Algerian regions: Mostaganem (Mediterranean coastal), Adrar (hyper-arid), and Tamanrasset (mountainous hyper-arid Sahara). Various methods like DPPH radical scavenging assay, protein inhibition assay and well diffusion assay were used to determine the antioxidant activity, Anti-inflammatory activity and antibacterial activity respectively. Quantitative methods like Follin ciocalteau assay, vanillin-HCl assay, Ferric chloride assay and Aluminum chloride assay were used to determine the total phenolic content, condensed tannins, hydrolysable tannins, and total flavonoid content respectively. A comprehensive comparative analysis revealed significant regional disparities (significance determined using ANOVA, p < 0.05) in physicochemical and phytochemical traits. Seeds from Mostaganem exhibited the highest dry matter content (99.25 ± 0.32%), mineral matter (6.44 ± 0.39%), and the lowest organic matter (93.55± 0.35%), coupled with the phytochemical profile, total phenolic content (TPC: 34.83 ± 4.33 mg GAE/g DW), condensed tannins (CT: 7.25 ± 0.29 mg CE/g DW), and hydrolysable tannins (HT: 2.29 ± 0.07 mg GAE/g DW), with Tamanrasset having the highest phytochemical profiles (TPC: 37.76 ± 2.22 mg GAE/g DW), (TFC: 6.04 ± 0.89 mg QE/g DW), and (CT: 12.26 ± 0.77 mg CE/g DW). Antioxidant capacity, evaluated via DPPH radical scavenging assay, demonstrated a dose-dependent inhibition, with the lowest IC₅₀ observed in Tamanrasset (2.13 ± 0.05 mg/mL), outperforming Mostaganem (2.64 ± 0.08 mg/mL) and Adrar (3.25 ± 0.10 mg/mL). Protein denaturation inhibition assay revealed potent anti-inflammatory activity, particularly in Mostaganem (49.72 ± 2.22%) and Adrar (49.26 ± 1.65%) samples, closely approximating the reference drug diclofenac (52.96 ± 1.22%). Antibacterial tests against Pseudomonas aeruginosa, Bacillus cereus, Proteus mirabilis, Klebsiella pneumonia, Salmonella paratyphi with Staphylococcus aureus and Escherichia coli demonstrating superior inhibition zones in Tamanrasset and Adrar extracts (15.3 ± 0.5 mm and 13.6 ± 0.4 mm, respectively), indicating robust antimicrobial potential. Multivariate principal component analysis (PCA) underscored vi the strong correlation between environmental stressors (temperature, altitude, and edaphic factors) and the biosynthesis of bioactive metabolites. These findings emphasize that eco-climatic determinants substantially modulate the therapeutic capacity of Moringa oleifera, making regional provenance a critical factor in standardizing raw materials for phytopharmaceutical and nutraceutical applications.