GC-MS Phytochemical Profiling and Hypoglycemic Activity of Hydroalcoholic and Aqueous Extracts of Aristolochia aff. constricta Griseb

Species of the genus Aristolochia have been widely reported for antidiabetic activity, but Aristolochia aff. constricta, used in traditional Ecuadorian medicine, lacks scientific evidence of hypoglycemic activity. This study analyzed the chemical composition and hypoglycemic activity of hydroalcoholic and aqueous stem extracts of A. aff. constricta, obtained by maceration and decoction, and analyzed by GC-MS after derivatization. Hypoglycemic activity was evaluated using an acute oral glucose tolerance test (OGTT) and a streptozotocin-induced hyperglycemia model in albino Wistar rats, with metformin and glibenclamide as reference drugs. Thirty compounds were tentatively annotated in the hydroalcoholic extract and 27 in the aqueous extract, mainly polyols, lactonic compounds, organic acids, fatty acids, a phenolic derivative, and carbohydrates; palmitic acid and fructofuranose were the most abundant in both. A two-way mixed ANOVA showed significant treatment, time, and interaction effects (p < 0.0001) in both models. The hydroalcoholic extract at 400 mg/kg produced the greatest glucose reduction; at day 7 of the streptozotocin assay, glucose values did not differ statistically from metformin and glibenclamide, although no formal equivalence testing was performed. However, area-under-the-curve analysis of the OGTT showed significantly higher glycemic exposure for the hydroalcoholic extract than for both reference drugs (p = 0.0001 and p = 0.0002, respectively), suggesting that its hypoglycemic effect depends on repeated rather than acute administration. These findings provide preliminary pharmacological evidence of the hypoglycemic activity of A. aff. constricta extracts; aristolochic acids were not evaluated due to unavailable certified standards, and toxicological evaluation is required before any therapeutic use in humans.