| Steroidal saponin is an important kind of constituent in Chinese Herbal and it shows a lot of pharmacological activites, especially in prevention of cardiovascular and cerebrovascular diseases. Lots of famous tradditional Chniese medicine, such as rhizoma of of Anemarrhena asphodeloides Bunge, Ophiopogon japonicus Ker-Gawl. and Paris polyphylla Smith var., are rich in steroidal saponins. Now, some medicines, such as Di'ao Xinxuekang, Xinnaoshutong and Chuanlongguanxinning and so on, which are made of some total steroidal saponins, has been developed in China. In addition, some steroidal saponins also show a great potential value to develop, such as Timosaponin BII, which should effectively significatnly increase the cholinergic receptors, improve cerebral ischemia and ischemic injury and enhance the abilitiy of learning and memory with good safety. Trigonella foenum-graecum L. (fenugreek, Leguminosae), which is an annual herb, has been widely cultivated in China. The seeds of this plant (fenugreek seeds) have long been known as a traditional medicine used for tonic and stomachic purpose. In Petroleum industry, the galactomannan was extracted to be used to increase the petrolic production. It is reported that fenugreek seeds abounded in steroidal saponins, and that was also confirmed by our preliminary phytochemical ivestigation. The content of total steroidal saponins could reach to 6.5%, which suggests that fenugreek seeds have great value to research.Totally 53 compounds were isolated from frenugreek seeds and transformation products of total furostanol saponins by column chromatography on macroporous resin SP825, silica-gel and octadecylsilanized silica-gel (ODS) and semi-preparative RP-HPLC, and the structures of 50 compounds were determined finally by chemical evidence and 1D NMR, 2D NMR and MS spectra.The furostanol saponins were the main type steroidal saponins in fenugreek seeds. In our work, we obtained 23 furostanol saponins and 1 spirostanol saponin from fenugreek seeds。In addition, 8 flavonoid-C-glycosides and 2 diterpene glycosides were isolated. Among them, 8 furostanol saponins and 2 diterpene glycosides were new compounds. Previous studies suggested that the activities of spirostanol saponins on platelet aggregation and cell toxicity were stronger than corresponding furostanol saponins. To fenugreek seeds, it contained various furostanol saponins though little spirostanol saponins existed. We converted the furostanol saponins of fenugreek seeds by enzymatic hydrolysis withβ-gucosidase to the correspongding spirostanol saponins, and 9 spirostanol saponins and 7 mixtures of 25R/S isomers were isolated at the end. 7 spirostanol saponins were new compounds, and 5 new structures from 7 mixtures of 25R/S isomers.The structures of 8 new furostanl saponins and 12 new spirotanl saponins were determined as (25S)-26-O-β-D-glucopyranosyl-5-en-furotane-3β,22α,26-triol 3-O-β- D-glucopyranosyl-(1â†'6)-β-D-glucopyranosyl-(1â†'3)-β-D-glucopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (1), (25R)-26-O-β-D- glucopyranosyl -5-en-furotane-3β,22α,26-triol 3-O-β-D-glucopyranosyl-(1â†'6)-β-D- glucopyranosyl- (1â†'3)-β-D-glucopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranosi-de (2), 26-O-β-D-glucopyranosyl-5,25(27)-dien-furostane-3β,22α,26-triol 3-O-α-L-rh- amnopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (3), (25R) -26-O-β-D-glucopyranosyl-5-en-furostane-2α,3β,22α,26-tetrol 3-O-α-L-rhmanopyran- osyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (4), 26-O-β-D-gluco- pyranosyl-5α-25(27)-en-furostane-2α,3β,22α,26-tetrol3-O-β-D-glucopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (5), (25S)-26-O-β-D-glucopyran- osyl-5α-furostane-2α,3β,22α,26-tetrol 3-O-β-D-glucopyranosyl-(1â†'4)-[α-L-rhmanop- yranosyl-(1â†'2)]-β-D-glucopyranoside (6), (25R)-26-O-β-D-glucopyranosyl-5α-furos- tane-2α,3β,22α,26-tetrol 3-O-β-D-glucopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (7), (25R)-26-O-β-D-glucopyranosyl-5-en-furostane-2α,3β, 22α,26-tetrol 3-O-α-L-rhamnopyranosyl-(1â†'4)-α-L-rhmanopyranosyl-(1â†'4)-[α-L-rh- amnopyranosyl-(1â†'2)]-β-D-glucopyranoside(8), (25S)-5α-spirostane-2α,3β-diol 3-O-β-D-xylopyranosyl-(1â†'6)-β-D-glucopyranoside (33a), (25R)-5β-spirostane-3β-ol 3-O-β-D-xylopyranosyl-(1â†'6)-β-D-glucopyranoside (34b), (25R)-5-en-spirostane-2α, 3β-diol 3-O-α-L-rhamnopyranosyl-(1â†'4)-[α-L-rhmanopyranosyl-(1â†'2)]-β-D-glucop- Yranoside (35), (25R)-5-en-spirostane-3β-ol3-O-β-D-glucopyranosyl-(1â†'6)-[β-D-xyl- opyranosyl-(1â†'4)]-β-D-glucopyranosyl-(1â†'3)-β-D-glucopyranosyl-(1â†'4)-[α-L-rha-mnopyranosyl-(1â†'2)]-β-D-glucopyranoside (39), 22β-(25R)-5-en-spirostane-3β-ol 3- O-α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyranoside(40), 5,25(27)-dien-spirostane- 3β-ol 3-O-α-L-rha-mnopyranosyl-(1â†'2)-β-D-glucopyranoside (41), 5,25(27)-dien- spirostane-2α,3β-diol-3-O-α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyranoside(43), 5α-25(27)-en-spirostane-2α,3β-diol 3-O-α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyr- anoside (44), (25S)-5-en- spirostane-2α,3β-diol 3-O-α-L-rhmanopyranosyl-(1â†'2)-β- D-glucopyranoside (45a), (25R)-5-en-spirostane-2α,3β-diol-3-O-α-L-rhamnopyranos- yl-(1â†'2)-β-D-glucopyranoside (45b), (25S)-5α-spirostane-2α,3β-diol3-O-α-L-rhamn- opyranosyl-(1â†'2)-β-D-glucopyranoside (46a), 5,25(27)-dien-spirostane-3β-ol 3-O-β-D-glucopyranosyl-(1â†'6)-[β-D-xylopyranosyl-(1â†'4)]-β-D-glucopyranosyl-(1â†'3)-β-D-glucopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl-(1â†'2)]-β-D-glucopyranoside (48). The 2 new diterpene glycosides were determined as Kura-5,16-dien-7-one-18-oic acid,methyl ester, 3β, 6, 13β-triol 3-O-β-D-glucopyranoside (49), Kura-5,16-dien-7-one-18-oic acid , methyl ester, 3β, 6, 13β-triol 3-O-α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyranoside (50).The structures of known compounds were determined as Trigoneoside Ib (9), TrigoneosideIa (10), TrigoneosideXb (11), Protodioscin (12), Compound C (13), Trigoneoside IVa (14), Glycoside F (15), Trigoneoside VI (16), Trigoneoside Vb (17), Trigoneoside Va (18), Trigoneoside XIIIa (19), Parvifloside (20), Trigoneoside IIa (21), Trigoneoside IIb (22), Glycoside D (23), Dioscin (24), Isovotexin (25), Vitexin (26), Apigenin 6,8-di-C-β-D-glucopyranoside (27), Apigenin 6-C-β-D- galactopyranosyl-8-C-α-L-arabinopyranoside (28), Apigenin 6-C-α-L- arabinopyranosyl-8-C-β-D-galactopyranoside (29), Isoorientin (30), Isoschaftoside (31), Orientin (32), Fenugreek saponin I (33b), Fenugreek saponin II (34a), (25R)- 5α-spirostane-2α,3β-diol 3-O-α-L-rhamnopyranosyl-(1â†'4)-[α-L-rhamnopyranosyl- (1â†'2)]-β-D-glucopyranoside (36), Ziggiberoside A3 (37a), Deltonin (37b), Collettinside III (38a), Dioscin (38b), Ziggiberoside A1 (42a), Prosaponin A of Dioscin (42b), Fengreek saponin III (46b), Sansevistain 1 (47).Mainly, a series of frustanol saponins and spirostanol saponins were isolated from frenugreek seeds and their total frustanol saponins transformation products and The preliminary investigation on inhibitory effect on rat platelet aggregation suggestted some of the spirostanol saponins showed the potential inhibitory activity on platelet aggregation, which was significant to the study on frenugreek seeds, especially on the residue after the extraction of galactomannan. |
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