✍ Scribed by Xue Gao; Chang-Jun Lin; Wei-Dong Xie; Tong Shen; Zhong-Jian Jia
No coin nor oath required. For personal study only.
Four new, highly oxygenated oplopane-type sesquiterpenes (3 -6) were isolated from the roots of Ligularia narynensis, together with four known compounds, and their structures were elucidated by spectroscopic methods and comparison with literature data. Selected congeners were evaluated for their in vitro cytotoxic activities against cultured SMMC-7721 (human hepatoma), L02 (human hepatocyte), and HL-60 (human promyelocytic leukemia) cells, but were found to be inactive.
Introduction. -The genus Ligularia has been placed taxonomically in the tribe Senecioneae of the family Compositae, with ca. 110 species being distributed within mainland China [1]. More than 27 Ligularia species have been used as traditional Chinese medicinal herbs against fever, pain, inflammation, and intoxication, and to invigorate blood circulation [2]. In our previous chemical and biological investigation of this genus [3], we found that eremophilanolides and benzofuranolides are the most-widespread secondary metabolites, oplopane sesquiterpenes being rare within Ligularia.
Recently, we reported the structure determination of the two oplopane-type sesquiterpenes 1 and 2 from Ligularia narynensis [4]. In a continuation of our phytochemical studies, we herein report the isolation and structure elucidation of four new, highly oxygenated oplopane-type sesquiterpenes, compounds 3 -6, from the roots of L. narynensis, together with two known eremophilanolides. Selected isolates were evaluated against a small panel of human-cancer cell lines for potential cytotoxic effects.
Results and Discussion. -The pulverized, air-dried roots of L. narynensis were extracted with petroleum ether/Et 2 A C H T U N G T R E N N U N G O/MeOH 1 : 1 : 1. Extensive purification by column chromatography on silica and RP-18 gel afforded compounds 1 -6, and two eremophilanolides (see below).
For compound 3, the molecular formula C 30 H 42 O 10 was determined by HR-ESI-MS (m/z 580.3111
10 ; calc. 580.3122)). Its IR spectrum showed absorption bands for C=O (1734) and C=C (1655 cm À1 ) groups. In the 1 H-and 13 C-NMR spectra of 3 (Tables 1 and2), one AcO group, one (4-acetoxy-3-methylpent-2enoyl)oxy group, and one (2-methylbutanoyl)oxy group were identified, as supported by the EI mass spectrum. Analysis of 1D-and 2D-NMR (Tables 123) and circulardichroism (CD) data enabled us to elucidate the structure of 3 as (1S,3aR,5S,6R,-A C H T U N G T R E N N U N G 7S,7aR)-1-(1-acetoxyethyl)octahydro-6-[(2-methylbutanoyl)oxy]-4-methylidene-7-[(2S)-A C H
📜 SIMILAR VOLUMES
Introduction. -The genus Ligularia has been taxonomically placed in the Compositae (tribe Senecioneae), and comprises ca. 100 species in China [1]. Some 27 species in this genus have long been used as folk remedies for their antibiotic, antiphlogistic, and antitumor activities [2]. Ligularia plants
## Abstract magnified image Four new eremophilane‐type sesquiterpenes, 3__β__‐(acetyloxy)‐6__β__‐(2‐methylbutanoyloxy)‐10__β__‐hydroxyeremophil‐7(11)‐en‐12,8__α__‐olide (**1**), 3__β__‐(acetyloxy)‐6__α__,7__α__‐epoxy‐11‐noreremophil‐9(10)‐ene‐8,11‐dione (**2**), 3__β__‐hydroxy‐11‐noreremophila‐6(7
## Abstract Five new eremophilane‐type sesquiterpenes, 3__β__‐(acetyloxy)‐7‐hydroxynoreremophila‐6,9‐dien‐8‐one (**1**), 8__β__‐hydroxy‐2‐dehydroxyliguhodgsonal (**2**), 3__β__‐(acetyloxy)‐11‐methoxy‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid (**3**), 3__β__‐(acetyloxy)‐11‐(2′‐methylbutanoyloxy)‐8‐oxoere