title: Biflavans, Flavonoids, and a Dihydrochalcone from the Stem Wood of Muntingia calabura and Their Inhibitory Activities on Neutrophil Pro-Inflammatory Responses.
abstract: Muntingia calabura (Tiliaceae) is commercially used in healthcare for the improvement of hypertension, myocardial infarction, spasm, and inflammatory conditions. Its fruits can be processed into jam and the leaves can be used for making tea. In the work reported herein a new biflavan, (M),(2S),(2''S)-,(P),(2S),(2''S)-7,8,3',4',5',7'',8'',3''',4''',5'''-decamethoxy-5,5'' biflavan (1), a new flavone, 4'-hydroxy-7,8,3',5'-tetramethoxyflavone (2), and a new dihydrochalcone, (R)-2',β-dihydroxy-3',4'-dimethoxydihydrochalcone (3), have been isolated from the stem wood of M. calabura, together with 12 known compounds (4-15). The structures of these new compounds were elucidated by the interpretations of extensive spectroscopic data. Among the isolated compounds, 5-hydroxy-7-methoxyflavone (5), quercetin (6), and (2S)-7-hydroxyflavanone (10) exhibited potent inhibition of fMLP-induced superoxide anion generation by human neutrophils, with IC50values of 1.77 ± 0.70, 3.82 ± 0.46, and 4.92 ± 1.71 μM, respectively.
authors.affiliation: Chung-Jen Junior College of Nursing, Health Sciences and Management, Chiayi 600, Taiwan. m049@cjc.edu.tw.
authors.forename: Wen-Lung
authors.initials: WL
authors.lastname: Kuo
authors.affiliation: Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan. liaoch@mail.cgu.edu.tw.
authors.forename: Hsiang-Ruei
authors.initials: HR
authors.lastname: Liao
authors.affiliation: Department of Pharmacy, Tajen University, Pingtung 907, Taiwan. jjchen@tajen.edu.tw.
authors.forename: Jih-Jung
authors.initials: JJ
authors.lastname: Chen