188
Journal of Natural Pr&s Vol. SO, No. 2, pp. 188-190, Mar-Apr 1987
ISOLATION AND HYPOGLYCEMIC ACTIVITY OF QUINQUEFOLANS A, B, AND C, GLYCANS OF PANAX QUZNQUEFOLZUM ROOTS’ YOSHITERU OSHIMA,KUNIKOSATO, and HIROSHI HIKINO* Pharmuseutical Institute, Tohoku University, Aoba-yam, Sendai 980,Japan hSTRACT.-An H,O extract of the American crude drug “Amerika-ninjin” (American ginseng), Panax quinque$olium roots, exhibited significant hypoglycemic activity in mice. Activity-guided fractionation of the extract led to isolation of three glycans, quinquefolans A, B, and C, which displayed hypoglycemic effects in normal and alloxan-induced hyperglycemic mice.
We have recently reported isolation and hypoglycemic activity of the polysaccharides of the Oriental crude drug “ninjin” (ginseng), the roots of Panaxginseng C.A. Meyer (Araliaceae) collected from Korea, China, and Japan (1-6). In continuation to this work we now examined Panax quinquefolium L.,another species of Panax in North America. The crude drug prepared from the roots of this species is known as “Amerikaninjin” (American ginseng), which has been used clinically as a substitute for Oriental ginseng (a tonic and sedative agent) mainly in China. Although physiological actions of the constituents from this crude drug were mentioned in the literature, no report on hypoglycemic activity was found. Preliminary hypoglycemic results exhibited by the H 2 0 extract of American ginseng prompted us to investigate the active principles which resulted in the isolation of three hypoglycemic glycans. RESULTS AND DISCUSSION American ginseng was first extracted with MeOH and then with H20. When the H,O extract was administered ip to normal mice, a significant lowering of blood sugar level was observed (Table 1). The crude polysaccharide fraction was obtained from the extract by usual methods, and this fraction was chromatographed over DEAEToyopearl, Sephacryl S-200 and S-500 to furnish three glycans which are now named as quinquefolans A, B, and C. Homogeneity of these glycans was substanriared by electrophoresis, gel filtration, and DEAE-Toyopearl chromatography. The molecular weights of these quinquefolans were estimated to be ca. >2.0 X lo6 by gel chromatography over Sephacryl S-500. Acid hydrolysis, reduction, and acetylation followed by glc of these glycans showed that the neutral sugar components were mannose and glucose (molar ratio, 1.0:2.3) for quinquefolan A, mannose and glucose (1.0:5.5) for quinquefolan B, and xylose for quinquefolan C. By using the modified carbasole-H,S04 method, the acidic sugar components in quinquefolans A, B, and C were found to be 10.8, 11.7, and 7.1%, respectively. Elemental analysis showed the presence of some peptide moieties in these glycans which was confirmed by the Lowry method (2.7, 2.9, and 2.3%, respectively). The property of these glycans which was mentioned above was different from that of earlier reported glycans from ginseng (1-6). When the quinquefolans were injected ip to normal mice, they showed significant hypoglycemic activity without changing the food intake of the treated-mice. Among them, quinquefolan A exhibited the most intense effect (Table 1). Ip injection of quin-
‘Antidiabetes drugs, Part 26. Also Part 116 in the validity of the Oriental medicines
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Oshima etal. : Activity of Quinquefolans
Mar-Apr 19877
TABLE1. Effect of H 2 0 Extract of Panax quinquq%liumRoots, and Qunquefolans A, B, and C on Plasma Glucose Level in Normal Mice (n=5) Relative glucose level
mb control . . . . extract . . . . control . . . . quinquefolanA
. . . .
. . . .
. . . .
control . . . . . . quinquefolan B . .
io4‘ 10 30 100 10 30
100 100 100 100 100 100 100 100 100 100 100 100 100 100
100
control . . . . . . quinquefolanc . .
10 30 100
24 (ha)
7
0
m2SE 10722 7726+fd 9722 4623*+ 45 k 2*+ 43+2+* 9722 9026 9423 8324* 11624 67 f6+* 6823*+ 652 If*
100
72 100 47 47 45 100 92 97 85 100
58 58 56
mkSE
%
107 f3 9029 9424 70k3++ 69+5+* 52k4++ 9424 10024 95k5 902 1 12526 86*6** 8625** 6923*+
100 84 100 75 74 55 100 106 101 96 100 69 69 55
“Time after administration. bPlasma glucose level at 0 h: 140- 170 mg/dl. ‘Crude drug equivalent. dSignificantly different from the control, *p
