Plants of the genus Hypericum contain various types of secondary metabolites that exhibited extensive biological activities. In the ongoing efforts to discover natural neuroinflammatory inhibitors with the potential to develop into therapeutic agents for neurodegenerative diseases, two new benzophenone glycosides, hyperewalones A and B (1 and 2), along with eight known compounds (3-10), were isolated from the aerial parts of Hypericum przewalskii. Their structures were elucidated by comprehensive analysis of IR, HRESIMS, 1D and 2D NMR spectra, and chemical derivatization. The anti-neuroinflammatory activity of compounds 1-10 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated BV-2 microglial cells. Compounds 2, 4, 6-8 exhibited significant anti-neuroinflammatory activity with IC50 values of 0.61-4.90 μM. These findings suggest that the benzophenone, ionone, and flavonoid glycosides isolated from H. przewalskii are promising anti-neuroinflammatory compounds worthy of further investigations.
Keywords: Hypericaceae; Hypericum przewalskii; anti-neuroinflammatory activity; antimicrobial activity; benzophenone glycoside.