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Endiandric acid analogs from the roots of Beilschmiedia tsangii
Beilschmiedia tsangii (Lauraceae) is a medium sized evergreen tree, distributed in Tonkin, Vietnam to Yunnan, Kwangsi and Kwangtung, China and south of Taiwan . There are only two species of Beilschmiedia in Taiwan. The stems and leaves of B. tsangii and the roots of B. erythrophloia have been reported their chemical constituents and bioactivities in our previous studies[2–5]. The methanolic extract from the roots of B. tsangii showed antitubercular activity against Mycobacterium tuberculosis H37Rv in vitro and it has never been studied. The aims of this study are the isolation of chemical constituents and antitubercular activity from the methanolic extract of the roots, which was partitioned to get EtOAc layer, H2O layer and insoluble part. Bioassay-guided fractionation of active EtOAc layer led to the isolation of three new compounds, erythrophlotsangine A (3), erythrophlotsangine B (4), and endiandric acid K (7), together with four known compounds. The structures of isolates were elucidated by spectral 2D NMR analysis. Antitubercular activity assay of the isolates is still in progress.
References: 1. Liao JC (1996) Flora of Taiwan, Editorial Committee of the Flora of Taiwan, Taipei.
2. Yang, PS. et al. (2008) Helv. Chim. Acta 91: 2130–2138.
3. Yang, PS. et al. (2009)J. Nat. Prod. 72: 53–58.
4. Chen, JJ. et al. (2006) Planta Med. 72: 351–357.
5. Chen, JJ. et al. (2007) Planta Med. 73: 567–571.