Anti-angiogenic activity of iridoids from Galium tunetanum

The phytochemical study of Galium tunetanum Lam., Rubiaceae, leaves led to the isolation of 13 com-pounds from the chloroform–methanol and the methanol extracts, including six iridoid glycosides,one non-glycoside iridoid, two p-coumaroyl iridoid glycosides, two phenolic acids, and two flavonoidglycosides. The structural determination of the isolated compounds was performed by mono- and bidi-mensional NMR spectroscopic data, as well as ESI-MS experiments. All compounds were isolated fromthis species for the first time. The anti-angiogenic effects of the isolated iridoids were also reported onnew blood vessels formation using the chick embryo chorioallantoic membrane as in vivo model. Resultsshowed that among the isolated iridoids tested at the dose of 2 g/egg, asperuloside (1), geniposidic acid(2), and iridoid V1 (3) reduced microvessel formation of the chorioallantoic membrane on morphologicalobservations using a stereomicroscope. The anti-angiogenic effects of the active compounds, expressedas percentages of inhibition versus control, were 67% (1), 59% (2), and 54% (3), respectively. In addition,the active compounds were able to inhibit angiogenesis in the chorioallantoic membrane assay, in adose-dependent manner (0.5–2 g/egg) as compared to the standard retinoic acid.