Four Novel Phenanthrene Derivatives with -Glucosidase Inhibitory Activity from .

Four new phenanthrene derivatives, gastrobellinols A-D (), were isolated from the methanolic extract of (Rchb.f.) Kuntze, along with eleven known phenolic compounds including agrostophyllin (), agrostophyllidin (), coniferyl aldehyde (), 4-hydroxybenzaldehyde (), agrostophyllone (), gigantol (), 4-(methoxylmethyl)phenol (), syringaldehyde (), 1-(4'-hydroxybenzyl)-imbricartin (), 6-methoxycoelonin (), and imbricatin (). Their structures were determined by spectroscopic methods. Each isolate was evaluated for α-glucosidase inhibitory activity. Compounds , , , , , , and showed higher activity than the drug acarbose. Gastrobellinol C () exhibited the strongest -glucosidase inhibition with an IC value of 45.92 μM. A kinetic study of showed competitive inhibition on the -glucosidase enzyme. This is the first report on the phytochemical constituents and -glucosidase inhibitory activity of