[Study on chemical constituents of Rhododendri Mollis Flos]

This study investigated the chemical constituents of Rhododendri Mollis Flos. The n-butanol fraction of 95% ethanol extract of Rhododendri Mollis Flos was separated and purified using chromatographic techniques, including normal-phase silica gel, ODS, and Sephadex LH-20 column chromatography. The structures of the isolated compounds were identified by spectroscopic techniques. Seven compounds were isolated and identified as rhodomollein LXⅦ(1), rhodomollein X(2), nivalenol(3),(3S,6S)-cis-linalool-3,7-oxide-β-D-glucopyranoside(4), thymidine(5), cyclo(Ala-Tyr)(6), and(S)-5-hydroxypyrrolidin-2-one(7). Among them, compound 1 was identified as a new compound, and compound 3 was isolated from this plant for the first time. The analgesic activity of compound 1 was evaluated using the acetic acid-induced writhing test. At a dose of 5.0 mg·kg~(-1), compound 1 showed a 75.4% inhibition rate in the writhing test, indicating significant analgesic activity.