Iridoids with anti-inflammatory effect from the aerial parts of Morinda officinalis How

Morinda officinalis How was widely applied to alleviate symptom like impotence, menstrual disorders, osteoporosis, and rheumatoid arthritis. To expand resources usage, phytochemistry of the aerial parts was studied and the structures of compounds were elucidated based on NMR, HRESIMS, IR and UV. Moreover, the anti-inflammatory effect and possible mechanism were investigated by Griess kit, RT-qPCR, ELISA, western blot and molecular docking on LPS-induced inflammation in RAW 264.7 cells. Herein, we isolated and identified 16 iridoid derivatives, including seven new iridoids officinaloside A-G (1–7) and nine known iridoids. All the compounds were safe to RAW 264.7 cells. Luckily, compounds 5 and 6 showed inhibitory effect on production of NO, and decreased the expression of inflammatory cytokines at mRNA and protein levels in a dose-dependent way. The possible mechanism of their anti-inflammation may be the affinity interaction between 5 with COX-2 protein, and 6 with iNOS protein. Overall, compounds 5 and 6 exert promising effects in inhibiting inflammatory cytokines, indicating that they could be used as lead compounds for developing health products or clinical practice for inflammation, which provides a scientific basis for further sustainable development and usage of the aerial parts of Morinda officinalis How.