Influence of the Solvent and the Harvesting Site on the Content of Phenolic Compounds and the in Vitro Antidiabetic Potential of Leafy Stems and Roots of Phyllanthus amarus Schum. and Thonn.

Abstract

Purpose: The objective was to verify the impact of the solvent and the harvesting site on the content of phenolic compounds as well as the in vitro antidiabetic activity of leafy stems and roots of Phyllanthus amarus.

Methods: The polyphenols and total flavonoids were measured on the crude extracts, obtained after maceration for 48 hours with acetone-water 50:50 (v/v), and ethanol-water 70:30 (v/v) . These extracts were evaluated for their antioxidant properties by DPPH, ABTS, and iron reduction (FRAP) tests. Finally, the α-amylase inhibitory activity of the crude extracts was determined by the method using DNS.

Results: The results show that acetone-water favors polyphenol extraction, with a maximum content of 32.62 ± 0.85 mg EAG/100 mg DE in leafy stems from Banfora (LSBaAw). In contrast, ethanol-water extracted more flavonoids, with 4.59 ± 0.02 mg EQ/100 mg DE in roots from Bobo (RBoEw). For antioxidant activity, the ethanol-water extract of Bobo leafy stems (LSBoEw) showed the highest ABTS free radical scavenging activity (81.34 ± 1.07 µg/mL). In comparison, the ethanol-water extract of Banfora roots (RBaEw) showed the best DPPH free radical scavenging activity (55.71 ± 2.48 µg/mL). On the other hand, the acetone-water extract of Banfora leafy stems (LSBaAw) showed the highest iron reduction activity (15,445.81 ± 835.75 µmol EAA/100 mg DE). Finally, the highest α-amylase inhibitory activity was observed with ethanol-water extracts from roots (RBaEw: 98.45 ± 0.38%; RBoEw: 96.56±0.31%).

Conclusion: These results underline the importance of the choice of solvent, organ, and harvesting site in optimizing the use of Phyllanthus amarus. Further studies involving other solvents and environmental conditions will enable us to refine these observations and optimize the pharmacological potential of this plant.