New sesquiterpenoids with COX-2 inhibitory activity from the medical plant Physalis. alkekengi L. var. franchetii

Phytochemical investigations on Physalis. alkekengi L. var. franchetii, a widespread traditional Chinese medicine, led to the isolation and identification of three new sesquiterpenoids physalisitins A–C (1–3). Their structures were elucidated by NMR and HRESIMS analysis, and their absolute configurations were determined by quantum chemical NMR and ECD calculations, as well as by comparing their optical rotation values with those known analogues. All of the isolated compounds were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity. Compounds 1–3 dose-dependently inhibited the COX-2 enzyme with IC50 values of 3.22 ± 0.25, 6.35 ± 0.84, and 11.13 ± 1.47 μM, respectively.