From Green Extraction to Gut Bioaccessibility: Synergistic Potential of Ginkgo biloba , Astragalus membranaceus , and Salvia miltiorr

ABSTRACT

Green extraction technologies offer sustainable alternatives to conventional solvent‐based methods for recovering phytochemicals from medicinal plants. In this study, different blends of Ginkgo biloba leaves, Astragalus membranaceus roots, and Salvia miltiorrhiza roots were screened, and the 1:1:2 blend showed the strongest TPC‐based apparent synergistic effect on total phenolic content (TPC). Probe ultrasound‐assisted extraction (probe‐UAE), bath ultrasound‐assisted extraction, and microwave‐assisted extraction were then optimized using response surface methodology. Probe‐UAE yielded the highest TPC, with an experimental value of 342.73 mg GAE/g under the optimized conditions. HPLC analysis of the prevailing synergistic extract (PSE) revealed rosmarinic acid (249.58 μg/mL), chlorogenic acid (135.59 μg/mL), and catechin (36.93 μg/mL) as the predominant identified phenolic compounds. The PSE showed strong antioxidant activity (DPPH IC ₅₀  = 23.04 μg/mL; ABTS IC ₅₀  = 30.71 μg/mL; FRAP/reducing power = 260.27 μg AAE/mg extract; TAC = 345.20 μg AAE/mg extract), anti‐inflammatory activity (protein denaturation IC ₅₀  = 18.21 μg/mL), and α‐amylase inhibition (IC ₅₀  = 40.58 μg/mL). The extract also exhibited antimicrobial activity, with the highest inhibition zone against Staphylococcus aureus (30 mm; MIC = 15.62 μg/mL), and moderate cytotoxic activity against PC3 and MCF‐7 cells (IC ₅₀  = 84.82 and 109.76 μg/mL, respectively). Simulated gastrointestinal digestion showed that total phenolics and flavonoids remained bioaccessible across digestive phases, although phenolics decreased progressively toward the intestinal phase. Overall, the optimized tri‐herbal extract demonstrated multifunctional in vitro bioactivity and may represent a promising candidate for functional food and nutraceutical applications. Further in vivo validation and formulation studies are warranted.