Solvent-Dependent Chemical Profiles and Biological Activities of Pueraria lobata Root Extracts

Pueraria lobata (Willd.) Ohwi root is a traditional medicinal resource rich in bioactive isoflavonoids with known antioxidant and anti-inflammatory properties. However, the chemical composition and biological activities of P. lobata root extracts can vary depending on the extraction solvent. In this study, we systematically compared P. lobata root extracts prepared using water, ethanol (30%, 70%, and 100%), and methanol to evaluate the effects of solvent selection on extraction yield, HPLC-based chemical profiles of major isoflavonoids, antioxidant capacity, and cellular responses in vitro. Chemical characterization by HPLC revealed distinct solvent-dependent differences in the relative abundance of key isoflavonoids, including puerarin, daidzin, and daidzein, defining characteristic chemical profiles for each extract. Antioxidant activity was evaluated using DPPH and ABTS radical scavenging assays, along with measurements of total polyphenol and flavonoid content. Cell viability was examined in HeLa cells using an MTT assay to define non-cytotoxic concentration ranges. The anti-inflammatory potential of the extracts was further assessed by measuring TNF-α-induced secretion of pro-inflammatory cytokines in HeLa cells. The results revealed marked solvent-dependent differences in extraction yield, chemical composition, and functional activity. Notably, methanol and ethanol extracts exhibited enriched isoflavonoid profiles associated with enhanced antioxidant and anti-inflammatory responses. Overall, this integrated chemical and functional evaluation demonstrates that solvent selection plays a critical role in determining the chemical characteristics and bioactivity of P. lobata root extracts. These findings provide a basis for rational solvent selection in the preparation of plant-derived extracts and support the potential use of P. lobata root as a functional source of antioxidant and anti-inflammatory compounds.