Facile preparation of optically active jasmonates and their biological activities in rice

A facile and efficient method has been developed for the optical resolution of racemic jasmonic acid (JA) on a relatively large scale and was successfully utilized for the preparation of optically pure (+)-JA and (-)-JA. We indicated that (+)-JA has lower growth inhibitory activity than (-)-JA in the rice seedling growth test and confirmed in line with an earlier observation that their respective biologically-active forms, (+)-JA-Ile and (-)-JA-Ile, show comparable inhibitory activities. We compared the metabolism of (+)-JA and (-)-JA into (+)-JA-Ile and (-)-JA-Ile, respectively, in the JA-deficient rice cpm2, and found that the exogenously applied (+)-JA was metabolized to the corresponding Ile conjugate less efficiently as compared with (-)-JA. Such metabolic rate difference may cause a discrepancy between biological potencies of (+)-JA and (-)-JA in rice. Abbreviations: FW: fresh weight; Ile: isoleucine; JA: jasmonic acid; JA-Ile: jasmonoyl-l-isoleucine; LC-ESI-MS/MS: liquid chromatography and electrospray ionization tandem mass spectrometry; MeJA: methyl jasmonate; OPDA: 12-oxophytodienoic acid.