Azerosides A and B: Two new phloroacetophenone glycosides from the roots of Dorema glabrum Fisch & CA Mey

Dorema glabrum (Apiaceae) is a monocarpic plant distributed in southern Caucasus. The gum-resin of this species is traditionally used as diuretic and anti-diarrheal and for the treatment of bronchitis and catarrh. In the present study, free radical-scavenging activity and total phenolic content of the essential oil together with n-hexane, chloroform, ethyl acetate, and methanol extracts of D. glabrum roots were evaluated in DPPH and Folin-Ciocalteu assays, respectively. Methanol extract with the highest free radical-scavenging activity (IC50 = 74.2 +/- A 6.6 mu g ml(-1)) and total phenolic content (186.7 +/- A 8.6 mg GAE/g) was subjected to phytochemical investigation using different chromatographic methods on the Si gel (normal and reversed-phase) and Sephadex LH-20 columns. Chemical constituents of the roots oil were also analyzed using GC and GC-MS. Two new phloroacetophenone glycosides, azerosides A (1) and azerosides B (7), along with nine known phenolic compounds, echisoside (2), pleoside (3), hyrcanoside (4), 7,8-dihydroferulic acid-4-O-beta-d-glucopyranoside (5), Lavandoside (6), 6,7,8-trihydroxycoumarin (8), chlorogenic acid (9), 4,5-Di-O-caffeoylquinic acid (10), and cynarin (11), were isolated and identified from D. glabrum roots. Among the isolated compounds, 8-11 exhibited potent free radical-scavenging activity (IC50 values of 1.8-2.7 mu g ml(-1)) in comparison with BHT (IC50 = 19.5 +/- A 0.8 mu g ml(-1)). Twenty-six compounds were also identified in the roots oil, among them myristicin (14.1 %) and elemicin (11.7 %), two bioactive phenylpropanoid derivatives, were main compounds. This study introduces D. glabrum as a source of phloroacetophenone glycosides and caffeoylquinic acid derivatives and suggests it as an appropriate candidate for further pharmacological and toxicological studies.