New Triterpenoid Glycosides from Centella asiatica

✍ Scribed by Zhi-Yong Jiang; Xue-Mei Zhang; Jun Zhou; Ji-Jun Chen

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: German
• Weight: 81 KB
• Volume: 88
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200590011

✦ Synopsis

Four new triterpenoid glycosides named asiaticoside C (1), D (2), E (3), and F (4) were isolated from the BuOH fraction of the EtOH extract of whole plants of Centella asiatica, together with three known compounds, asiaticoside (5), madecassoside (6), and scheffuroside B (7). Based on FAB-MS, IR, 1 H-and 13 C-NMR, and 2D-NMR data (HMQC, HMBC, COSY), the structures of the new compounds were determined as (2a,3b,4a)-23-

Introduction. ± The Umbelliferae Centella asiatica (L.) Urban has been widely cultivated as a vegetable or spice in China, Southeast Asia, India, Sri Lanka, Africa, and Oceanic countries, and used for skin diseases, diarrhea, eye diseases, inflammation, asthma, leprosy, and hypertension in southeast Asia [1]. To characterize an active compound for traditional effects of C. asiatica, the whole plants were extracted with EtOH under reflux to give a residue, which was suspended in H 2 O and partioned between CHCl 3 and BuOH. The BuOH fraction was separated by chromatographic techniques to give four new triterpenoid glycosides, named asiaticoside C (1), D (2), E (3), and F (4), together with three known compounds, asiaticoside (5) [2][3], madecassoside (6) [4], and scheffuroside B (7) [5] (Fig.). Herein, we report the isolation and the structure identification by FAB-MS, IR, 1 H-and 13 C-NMR, and 2D-NMR data (HMQC, HMBC, COSY) of asiaticoside C (1), D (2), E (3), and F (4).

Results and Dicussion. ± Asiaticoside C (1) was obtained as colorless amorphous powder. The IR spectrum of 1 showed absorptions for OH groups at 3441 cm À1 , an ester carbonyl at 1738 cm À1 , and an olefin moiety at 1655 cm À1 besides a stronger absorption at 1063 cm À1 suggesting a glycosidic linkage in the molecule. The high-resolution (HR) FAB-MS exhibited an accurate ion peak at m/z 999.5164 ([M À H] À ) in accordance with an empirical molecular formula C 50 H 80 O 20 . The negative-ion FAB-MS of 1 gave a quasi-molecular ion and fragment-ion peaks at m/z 999 (

, suggesting the presence of three sugar moieties in the molecule. After hydrolysis of 1 with 5% H 2 SO 4 in MeOH, glucose and rhamnose were identified by comparison with authentic samples on PC (paper chromatography). The quasi-molecular-ion peak established