Phytochemical Characterization of Pueraria tuberosa Root Extracts Using Microwave and Ultrasound-Assisted Extraction by LC-QTOF-MS

The increasing global demand for natural drugs, especially traditional medicines, has driven interest in plants like Kudzu (Pueraria tuberosa), renowned for its anti-inflammatory, antioxidant, antidiabetic, and anti-cancer properties. This study investigates the extraction and characterization of phytochemicals from Kudzu root, which is traditionally used in Ayurvedic and Chinese medicine. Extraction techniques, including microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and a combined approach (MAE + UAE), were optimized to enhance the yield of isoflavones and other phytochemicals. The high TPC (49.88 ± 0.22 mg GAE/g) and TFC (36.36 ± 0.54 mg QE/g) values are observed in the optimized sample (MAE + UAE) under extraction conditions of 100 W microwave power for 6 min with 400 W ultrasonic power for 40 min at 50 ℃. The combined MAE + UAE treatment significantly improved antioxidant activity, exhibiting the highest DPPH (76.44 ± 0.86%) and ABTS (90.76 ± 0.59%) scavenging rates with IC₅₀ value of 392.00 ± 0.39 μg/ml and 263.98 ± 0.53 μg/ml, as well as the higher FRAP value (22.77 ± 0.66 mg AAE/g). Phytochemical analysis through LC-QTOF-MS identified around 60 phytochemicals, including 10 glycosylated flavonoids, 24 isoflavonoids, five flavones and flavanols, five phenolic acids, some polyphenols, and other compounds. This study highlights the efficacy of the combined MAE + UAE method in enhancing phytochemical extraction. Furthermore, the extracts demonstrated improved functional and antioxidant activities, making them valuable for applications in functional foods and nutraceutical formulations.