3-(4-Carb-oxy-5-carboxyl-ato-1H-imidazol-2-yl)pyridin-1-ium monohydrate.

In the zwitterionic mol-ecule of the title compound, C(10)H(7)N(3)O(4)·H(2)O, one carboxyl group is deprotonated and the pyridine N atom is protonated. The pyridinium and imidazole rings form a dihedral angle of 5.23 (1)°. An intramolecular O-H⋯O hydrogen bond occurs. In the crystal, inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds link the zwitterions and water mol-ecules into sheets parallel to (102).

Study on chemical constituents from Mastic (Pistacia lentiscus) / 中国中药杂志

Phytochemical investigation on the methanolic extract of Mastic by using various chromatographic techniques led to the isolation of 9 compounds. Based on the analysis of spectroscopic data(NMR and MS) and/or comparisons with the data reported in the literature, their structures were elucidated as 3β,8α,13-trihydroxypolypoda-14-methoxy-14-methyl-17,21-diene(1), 4-hydroxymyrtenal(2),3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1, 2-diol(3), 2-oxo-Δ~3-4,5,5-trimethylcyclopentynyl acidic acid(4),(1S,2R,3R,5R)-6,6-dimethyl-4-methylidenebicyclo[3.1.1]-heptane-2,3-diol(5),(4R)-1-methyl-4-(1-hydroxyisopropyl)cyclohexene-6-one(6), 6,6-dimethyl-4-hydroxy[3.1.1]hept-2-ene-2-carboxylic acid(7), 6,6-dimethyl[3.1.1]hept-2-ene-2-carboxylic acid(8), 6,6-dimethyl-4-oxobicyclo[3.1.1]hept-2-ene-2-carboxylic acid(9). Compound 1 is a new compound and 2-9 were isolated from this species for the first time. In vitro cytotoxicity assay results indicated that compounds 1, 6 and 7 showed significant inhibitory effects against human lung cancer cell line A549 with IC_(50) values of 20.4, 25.1 and 22.5 μmoL·L~(-1).