Five 2-(2-Phenylethyl)chromones from Sodium Chloride-Elicited Aquilaria sinensis Cell Suspension Cultures

Five 2-(2-phenylethyl)chromones including a new one, (5S,6R,7S,8R)-5,8-dichloro-6,7-dihydroxy-2-phenylethyl-5,6,7,8-tetrahydro-4H-chromen-4-one (1), and four known ones (2-5), were isolated from 150 mM NaCl-elicited Aquilaria sinensis cell suspension cultures. In addition, three feruloyl amides (6-8), six nucleosides (9-14), (+)-syringaresinol (15), indole-3-carboxaldehyde (16), and two glycosides (17-18) were also obtained. The structures were unambiguously identified by analysis of their UV, IR, NMR, and HRESIMS data. The absolute configuration of the new 2-(2-phenylethyl)chromone (1) was established by a dimolybdenum tetraacetate-induced circular dichroism experiment. Compared to un-elicited cell lines, the appearance of 2-(2-phenylethyl)chromones in NaCl-treated cells occurred on the 3rd and 5th days of their treatment. 2-(2-Phenylethyl)chromones, feruloyl amides, nucleosides, and lignins have been reported to be closely related to plant defense; therefore, the identification of these compounds from NaCl-elicited A. sinensis cell suspension cultures would be useful for further exploring the mechanism of agarwood formation.