Solvent-Dependent Modulation of Antioxidant and Carbohydrate-Digestive Enzyme Inhibitory Activities in the Thai Traditional Boaw-Waan Formula

The Thai traditional herbal formula Boaw-Waan from Kap Choeng Hospital combines Mallotus repandus, Tinospora crispa, and Azadirachta indica (10:5:3 ratio), has been used in diabetes care. The study assessed antioxidant capacity and inhibition of α-glucosidase and α-amylase using three solvents: an aqueous decoction boiled for 15 minutes (KAP-DM-A), a 40% ethanol extract (KAP-DM-40), and an 80% ethanol macerate prepared for 7 days (KAP-DM-80), with five replicates per assay (n = 5). KAP-DM-40 produced the highest total phenolic content at 15.10 ± 0.68 mg GAE/g extract and a high total flavonoid content at 15.97 ± 0.39 mg QE /g extract, whereas KAP-DM-80 produced the highest total flavonoid content at 18.24 ± 0.49 mg QE /g extract. Antioxidant assays favored KAP-DM-40, which achieved IC50 values of 0.271 ± 0.011 mg/mL in DPPH and 0.215 ± 0.017 mg/mL in ABTS, and produced the highest FRAP value at 602.23 ± 0.10 mg TE/g extract. Enzyme inhibition was strongest for KAP-DM-A, with IC50 values of 0.038 ± 0.006 mg per mL for α-glucosidase and 0.036 ± 0.011 mg per mL for α-amylase, and both values were lower than those of acarbose at 0.143 ± 0.012 and 0.603 ± 0.191 mg/mL, respectively. Solvent choice has a clear effect on bioactivity, since hydroethanolic extraction favors recovery of antioxidant constituents while the traditional aqueous method yields stronger inhibition of diabetes-related digestive enzymes. Results support the traditional use of Boaw-Waan and suggest that combining aqueous and hydroethanolic extraction may capture both antioxidant and antihyperglycemic mechanisms relevant to diabetes management.