Research progress on anti-inflammatory activity of three kinds of iridoid glycosides in Chinese materia medica / 中草药

ABSTRACT

Iridoid glycosides are widely distributed in Chinese materia medica (CMM) with various biological activities such as anti-inflammation. They are also used as quality control constituents in some Chinese medicines. Iridoid glycosides are usually divided into nine-carbon skeleton iridoid glycoside type, ten-carbon skeleton iridoid glycoside type, and secoiridoid glycoside type. In this paper, 15 representative iridoid glycosides from three types which are received extensive attention (including geniposide, catalpol, gentiopicroside, etc) have been selected. Their anti-inflammatory effects and possible related mechanisms are summarized to find out the acting feature of different types. Through comparing the structures and function characteristics, it was concluded that the anti-inflammatory effects of iridoid glycosides were mostly related to NF-κB pathway and MAPK pathway. They have obvious inhibitory effects on TNF-α, IL-6, and IL-1β inflammatory factors, some of which could play a role by reducing the expression of iNOS and COX-2 in NLRP3, Nrf2/HO-1, PI3K, and other pathways. From the structure-activity relationship, the double bond on the cyclopentane, the C-11 substituent and the bond formation after ring opening in iridoid glycosides all have important effects on its anti-inflammatory activities.