Anti-inflammatory iridoids from the stems of Cistanche deserticola cultured in Tarim Desert.
In order to determine the chemical constituents of Cistanche deserticola cultured in Tarim desert, a systematically phytochemical investigation was carried out. The constituents were isolated by silica gel, Sephadex LH-20, MCI gel, ODS column chromatography, and semi-preparative HPLC. Their structures were determined on the basis of MS and NMR spectroscopic analyses, by chemical methods, and/or comparison with literature data. The anti-inflammatory activities of the isolates were evaluated for their inhibitory effects on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 mouse microglial cells. Nine iridoids were isolated and identified as cistadesertoside A (1), cistanin (2), cistachlorin (3), 6-deoxycatalpol (4), gluroside (5), kankanoside A (6), ajugol (7), bartsioside (8), and 8-epi-loganic acid (9). Compound 9 exhibited potent inhibition on the NO production with an IC50 value being 5.2 μmol·L(-1), comparable to the positive control quercetin (4.3 μmol·L(-1)). Compound 1 was a new iridoid, and compounds 5, 6, and 8 were isolated from this species for the first time.