Botanicals and phytochemicals from the bark of Hypericum roeperianum (Hypericaceae) had strong antibacterial activity and showed synergistic effects with antibiotics against multidrug-resistant bacteria expressing active efflux pumps.

Ethnopharmacological Relevance: Infections due to multidrug-resistant (MDR) bacteria constitute a real problem in the public health worldwide. Hypericum roeperianum Schimp. ex A.

Roeperone A, a new tetraoxygenated xanthone and other compounds from the leaves of Schimp. (Hypericaceae).

Chemical investigation of the methanol extract from the leaves of led to the isolation of a new tetraoxygenated xanthone along with eleven known compounds including six xanthones, one polyketide, one flavonoid, one ferulic acid derivative and two pentacyclic triterpenoids. Their structures were established on the basis of 1D- and 2D-NMR, UV, IR, and MS experiments, and by comparison of their spectroscopic data with those of similar compounds reported in the literature. The new xanthone was tested against a panel of eight bacterial strains including six Gram-negative and two Gram-positive bacteria.

A new polyketide from the bark of Schimp. (Hypericaceae).

The isolation and spectroscopic data of a hitherto undescribed polyketide () from Schimp. (Hypericaceae) together with six known compounds (-) is herein reported. The structure elucidation is based on extensive 1D- and 2D-NMR, infrared, UV and MS experiments.