Effect of Extraction Method and Ethanol Concentration on the Antioxidant and α-Glucosidase Inhibitory Activities of Hornstedtia scyphifera var. fusiformis Shoots:LC-HRMS/MS Profiling of the Antioxidant-Optimized Extract

Despite its traditional use in Sumatra, Hornstedtia scyphifera var. fusiformis (Zingiberaceae) has not been evaluated for antioxidant or α-glucosidase inhibitory activity in its shoots. Vegetative shoot extracts were prepared by maceration and reflux using 70% and 96% ethanol and assessed for total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH, CUPRAC, FRAP, ABTS), and α-glucosidase inhibitory activity. 96% ethanol extracts showed higher TPC, TFC, and antioxidant activity than 70% ethanol; maceration in 96% ethanol (M96) gave the highest TPC (138.87 ± 9.29 mg GAE/g) and CUPRAC activity (106.62 ± 1.59 mg AEAC/g). Reflux with 70% ethanol (R70), however, showed markedly stronger α-glucosidase inhibition (6811.94 ± 528.27 mg AEAGIC/g) than the other extracts despite low phenolic and flavonoid content. α-Glucosidase inhibition did not follow phenolic, flavonoid, or antioxidant parameters. In chemometric analysis (PCA, HCA) the extracts were separated mainly according to the ethanol concentration rather than extraction technique. LC-HRMS/MS profiling of the antioxidant-optimized M96 extract putatively annotated 20 secondary metabolites, led by the flavonol ermanin and the sesquiterpenoid nootkatone. Because only M96 was profiled, the compounds underlying R70’s α-glucosidase inhibition remain unidentified; extraction conditions thus affect the two activities differently, but the chemical basis of R70’s activity requires further investigation.