Chemical Constituents from the Leaves of and Their Bioactivities.

The leaves of have been consumed as Ku-Ding-Cha for clearing heat and removing toxins, and they have been used as a folk medicine for curing hypertension, diabetes, and obesity in China. The phytochemical research on the leaves of led to the isolation and identification of two new hexenol glycosides, two new butenol glycosides, and five new sugar esters, named ligurobustosides X (), X (), Y (), and Y () and ligurobustates A (), B (), C (), D (), and E (), along with seven known compounds ( and -). Compounds - were tested for their inhibitory effects on fatty acid synthase (FAS), α-glucosidase, and α-amylase, as well as their antioxidant activities. Compound showed strong FAS inhibitory activity (IC 4.10 ± 0.12 μM) close to that of the positive control orlistat (IC 4.46 ± 0.13 μM); compounds and revealed moderate α-glucosidase inhibitory activities; compounds - showed moderate α-amylase inhibitory activities; and compounds and displayed stronger 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) ammonium salt (ABTS) radical scavenging effects (IC 3.41 ± 0.08~5.65 ± 0.19 μM) than the positive control l-(+)-ascorbic acid (IC 10.06 ± 0.19 μM). This study provides a theoretical foundation for the leaves of as a functional tea to prevent diabetes and its complications.