Prionitosides A and B - two iridoid glycosides with anti-inflammatory and cytotoxic activities from Barleria prionitis

Two new iridoid glycosides, prionitosides A (1) and B (2), along with three known iridoid glycosides, acetylbarlerin (3), 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester (4) and 6-O-cis-p-coumaroyl-8-O-ace- tylshanzhiside methyl ester (5), were isolated from the whole plant of Barleria prionitis Linn. collected in Laos. Their structures were elucidated by spectroscopic analyses including 1D and( 2)D NMR, UV, IR, mass spectra and in comparison with the data reported in the literature. In addition, the inhibition of alpha-glucosidase, cytotoxicity, and anti-inflammatory activities of compounds 1-5 were investigated. Compound 3 showed strong inhibition of alpha-glucosidase activity with an IC50 value of 38.5 +/- 2.12 mu g/mL. Compound 2 had weak cytotoxicity against A549 cancer cell line (IC50 = 109.4 +/- 6.0 mu g/mL) and inhibition of nitric oxide production in RAW 264.7 cells (IC50 = 75.64 +/- 3.5 mu g/mL).