Inhibitory Effect of <i>Ilex Latifolia</i> Leaf Extract on Postprandial Increase in Blood Glucose Level

ABSTRACT Aim Kuding tea brewed from Ilex latifolia (IL) leaves has been traditionally consumed and regarded as “beauty‐slimming tea” and “longevity tea” in China, albeit supporting theoretical evidence is lacking. This study aims to determine whether IL leaves can be effectively used to prevent gastrointestinal dietary glucose absorption. Methods Mice were administered IL leaf extract (IL‐ext) with α‐starch orally and measured blood glucose levels. IL‐ext was partitioned with ethyl acetate‐H 2 O and further fractionated using reversed‐phase ODS column chromatography into mono‐caffeoylquinic acids (CQAs)‐, di‐CQAs, and triterpenoids‐enriched fractions. The components contained in each fraction were quantified using HPLC, and the inhibitory effect on maltase was evaluated via in vitro assay. Results The increase in blood glucose level after oral α‐starch administration was suppressed by treatment with 100 or 500 mg/kg of IL‐ext in mice. IL‐ext inhibited maltase activity, with the di‐CQA‐enriched fraction showing the strongest maltase inhibition. Among di‐CQAs, 3,4‐di‐CQA showed the strongest inhibition of maltase. Conclusion The intake of IL leaves with meals can prevent gastrointestinal glucose absorption by inhibiting the digestion of dietary carbohydrates. The 3,4‐di‐CQA contained in IL leaves appears to be a major bioactive component for inhibiting postprandial increases in blood glucose levels.