Flavonoids from the leaves of Cryptocarya chinensis with antituberculosis activity

T Chou; J Chen; C Peng; I Chen

doi:10.1055/s-0030-1264791

Planta Medica, Inhaltsverzeichnis

Flavonoids from the leaves of Cryptocarya chinensis with antituberculosis activity

T Chou ¹, J Chen ², C Peng ³, I Chen ¹

¹Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, College of Pharmacy, 100, Shih-Chuan 1st Road, 807 Kaohsiung, Taiwan
²Graduate Institute of Pharmaceutical Technology, Tajen University, Graduate Institute of Pharmaceutical Technolog, No.20, Weisin Rd., Sin-er Village, Yanpu Township, 907 Pingtung, Taiwan
³Faculty of Biomedical Laboratory Sciences, Kaohsiung Medical University, College of Health Science, 100, Shih-Chuan 1st Road, 80708 Kaohsiung, Taiwan

Abstract

Cryptocarya chinensis (Hance) Hemsl. (Lauraceae) is a medium-sized evergreen tree, distributed throughout southern China, Japan, and Taiwan. Flavonoids, pyrones, pavines, aporphines, benzylisoquinolines, lignans, and their derivatives are widely distributed in plants of the genus Cryptocarya, and many of these compounds exhibit cytotoxic and antioxidant activities. In our continuing studies on the antitubercular constituents of Formosan plants, over 400 species have been screened for in vitro antituberculosis activity to date, and C. chinensis has been found to be one of the active species. Studies on the neutral CHCl₃ fraction of leaves from this species has led to the isolation of two new tetrahydroflavanones, cryptochinone G (1) and cryptochinone H (2), and two new flavanones, crytoflavanone A (3) and crytoflavanone B (4), together with 8 known compounds (5-12). The structures of these new compounds were determined through spectroscopic analyses, including extensive 2D-NMR, ORD, MS and, IR. Among the isolates, cryptocaryone (5), cryptocaryanone B (6), and pinocembrin (7) showed antituberculosis activities with MICs of 25.0, 25.0 and 3.5 ug/mL against Mycobacterium tuberculosis, respectively. The structural elucidation of 1-4 and the antituberculosis activities of the isolates will be discussed in this symposium.