Saponins and Other Constituents from the Leaves of Aralia elata

Abstract

Aralia elata SEEM. (Araliaceae) is widely distributed in the northeast of China and Korea. Its root bark has been used as a folk medicine for tonic, anti-arthritic, and anti-diabetic effect.1) The young shoot of A. elata is a popular edible plant, especially in the spring in Korea and Japan. Many saponins have been isolated from this plant, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and were reported to show anti-diabetic activity, 17) cytoprotective effect on CCl 4 -induced hepatic injury, 7) ethanol absorption inhibitory effect, 6,14) and hypoglycemic activity. 10-12) Recently, we reported the isolation and identification of various triterpenoid saponins including two new saponins, durupcosides A and B, 2,3) and a cerebroside, aralia cerebroside 18) from the root bark of this plant. As part of our continuing search for antiinflammatory agents from plants, 19) a nonpolar n-hexane extract of the leaves of A. elata was subjected to a chemical investigation leading to the isolation of eight compounds, among which one was new. This paper deals with the isolation and characterization of the new triterpenoid saponin named durupcoside C (5), together with five known saponins (1-4, 6) and two known lipids (7, 8) from the n-hexane fraction of the leaves of A. elata.The dried leaves of A. elata was extracted with MeOH and partitioned as described in the Experimental section. Six saponins (1-6) and two lipids (7, 8) were isolated by successive chromatography using silica and reverse-phase C 18 from the n-hexane fraction. Five known saponins and two lipids were identified as a-hederin (1), 20) 4) urtica ceramides (7) 23) and arisaema glyceride 3 (8), 24) respectively, by direct comparison of the spectral data with the published values.Compound 5 was obtained as a white amorphous powder. A new triterpenoid saponin, together with five known saponins, were isolated from the nonpolar n-hexane fraction of the leaves of Aralia elata. The structure of the new saponin, durupcoside C, was elucidated as hedera-

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Isolation and tandem mass fragmentations of an anti-inflammatory compound from Aralia elata

“…Many triterpenoid saponins in A. elata have been reported to have hypoglycemic activity and cytoprotective effects on carbon tetrachloride-induced hepatic injury (Kim et al, 2005). The 3-O-monodesmoside structure of oleanolic acid, where C-3 is linked to sugars, has been reported as essential to inhibitory effects on ethanol absorption in rats as well as producing potent hypoglycemic effects in an oral glucose tolerance test in rats (Yoshikawa et al, 1993(Yoshikawa et al, , 1994(Yoshikawa et al, , 1995(Yoshikawa et al, , 1996.…”