Azerosides A and B: Two new phloroacetophenone glycosides from the roots of Dorema glabrum Fisch. & C.A. 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 (IC 50 = 74.2 ± 6.6 μg ml −1 ) and total phenolic content (186.7 ± 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 -β- 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 (IC 50 values of 1.8–2.7 μg ml −1 ) in comparison with BHT (IC 50 = 19.5 ± 0.8 μg 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.