Iridoid and phenylethanoid glycosides from the aerial part of Barleria lupulina

A new iridoid glycoside, barlupulin C methyl ester (1), together with two known phenylethanoid glycosides (2 and 3) and three known simple phenolic glycosides (4–6) were isolated from the aerial parts of Barleria lupulina Lindl., Acanthaceae. The structure of the new compound (1) was elucidated through 1D and 2D NMR spectroscopic data, and HR-ESIMS. Interestingly, compound (1) has a formate group attached to the C-6 hydroxy group of the glucose unit. Compounds 2–6 were identified as poliumoside (2), decaffeoylacteoside (3), protocatechuic acid 4-O-β-glucoside (4), vanillic acid 4-O-β-glucoside (5), and leonuriside A (6) on the basis of NMR spectroscopic data analyses and comparison with those reported in the literature. Compounds 3–6 were isolated from B. lupulina for the first time.

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