Studies on absorption, distribution, excretion and metabolism of ginseng saponins. VII. Comparison of the decomposition modes of ginsenoside-Rb1 and -Rb2 in the digestive tract of rats.

In order to clarify some similarities and differences of decomposition modes between 20(S)-protopanaxadiol (20(S)-ppd) saponins, represented by ginsenoside Rb1 (Rb1) and ginsenoside Rb2 (Rb2), the decompositions of Rb1 and Rb2 in the rat gastrointestinal tract, 0.1 N HCl and crude hesperidinase were investigated in detail. As in the case of Rb2 reported previously, Rb1 was hydrolyzed to 20(R,S)-ginsenoside Rg3 in 0.1 N HCl. On the other hand, hydroperoxidation of Rb1 occurred in rat stomach; the major hydroperoxide was separated and identified as the 25-hydroperoxy-23-ene derivative of Rb1 (VIII) by 1H- and 13C-nuclear magnetic resonance and fast atom bombardment mass spectrometry. The decomposition modes of 20(S)-ppd saponins (Rb1 and Rb2) differed from that of 20(S)-protopanaxatriol saponin (Rg1) in rat stomach. In rat large intestine, five decomposition products of Rb1 were observed by thin-layer chromatography, and these were identified as gypenoside XVII (G-XVII), ginsenoside Rd (Rd), ginsenoside F2 (F2), compound K (C-K) and VIII. The decomposition modes of Rb1 and Rb2, both 20(S)-ppd saponins, are considered to be different because of the hydrolysis rate in the terminal sugar moiety at the C-20 hydroxyl group in the rat large intestine. Using crude hesperidinase, Rb1 was decomposed to G-XVII, F2 and C-K, and Rb2 was decomposed to 3-O-beta-D-glucopyranosyl-20-O-[alpha-L-arabinopyranosyl(1----6)-b eta-D- glucopyranosyl]-20-(S)-ppd, F2 and C-K. Consequently, it appears that hydrolysis by beta-glucosidase, which is present in the rat large intestine, is distinct from that by crude hesperidinase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Six new dammarane-type triterpene saponins from the leaves of Panax ginseng

Six new minor saponins, together with known ginsenosides, were isolated from the leaves of Panax ginseng. The new saponins were named as ginsenoside-Rh5, -Rh6, -Rh7 -Rh8, -Rh9 and -Rg7, and their structures were elucidated on the basis of chemical and physicochemical evidence to be as follows: ginsenoside-Rh5: 3beta,6alpha,12beta,24zeta-tetrahydroxy-dammar-20(22),25-diene 6-O-beta-D-glucopyranoside (1), -Rh6: 3beta,6alpha12beta,20(S)-tetrahydroxy-25-hydroperoxy-dammar-23-ene 20-O-beta-D-glucopyranoside (2), -Rh7: 3beta,7beta,12beta,20(S)-tetrahydroxy-dammar-5,24-diene 20-O-beta-D-glucopyranoside (3), -Rh8: 3beta,6alpha,20(S)-trihydroxy-dammar-24-ene-12-one 20-O-beta-D-glucopyranoside (4), -Rh9: 3beta,6alpha,20(S)-trihydroxy-12beta,23-epoxy-dammar-24-ene 20-O-beta-D-glucopyranoside (5) and -Rg7: 3-O-beta-D-glucopyranosyl 3beta,12beta,20(S),24(R)-tetrahydroxy-dammar-25-ene 20-O-beta-D-glucopyranoside (6).     

Further bisabolenes and dammarane triterpenes of Commiphora kua resin

From the resins of Commiphora kua a novel bisabolene; 6-hydroxy-2-methyl-5-(5'-hydroxy-1'(R),5'-dimethylhex-3'-enyl)-phenol together with two new dammarane triterpenes, 3beta,16beta,20(S),25-tetrahydroxydammar-23-ene and 3beta-acetoxy-16beta,20(S),25-trihydroxydammar-23-ene, have been isolated. In addition, being reported are known compounds identified as 2-methyl-5-(4'(S)-hydroxy-1'(R),5'-dimethylhex-5'-enyl)-phenol, 2-acetoxyfuranodienone, 2-methoxyfuranodienone, 3beta,16beta,20(R)-trihydroxydammar-24-ene and its acetate derivative, 3beta-acetoxy-16beta,20(R)-dihydroxydammar-24-ene, and beta-amyrin and its acetate derivative. 2-Methyl-5-(4'(S)-hydroxy-1'(R),5'-dimethylhex-5'-enyl)-phenol displayed fungicidal activity against Cladosporium cucumernum on TLC assay.     

Dammarane triterpenes of Commiphora confusa resin

Fractionation of a steam distilled residue of Commiphora confusa resin has yielded four novel dammarane triterpenes characterised as (20S)-3beta-acetoxy-12beta,16beta-trihydroxydammar-24-ene, (20S)-12beta,16beta-trihydroxydammar-24-ene-3beta-O-beta-glucopyranoside, (20S)-3beta-acetoxy-12beta,16beta,25-tetrahydroxydammar-23-ene, and (20S)-3beta,12beta,16beta,25-pentahydroxydammar-23-ene. The known compounds beta-amyrin, 3beta-amyrinacetate, 2-methoxyfuranodienone, 2-acetoxyfuranodienone, (20R)-3beta-acetoxy-16beta-dihydroxydammar-24-ene, (20R)-3beta,16beta-trihydroxydammar-24-ene, 3beta-acetoxy-16beta-hydroxydammar-24-ene, 3beta-hydroxydammar-24-ene, 3beta-acetoxydammar-24-ene, and beta-sistosterol were also isolated from the same extract. The structures of the compounds were determined using spectroscopic, physical, and chemical methods.     

绞股蓝皂苷酸水解次生苷元的分离与鉴定

绞股蓝皂苷用5%硫酸水解,生成的次生皂苷元除已报道的人参二醇和2α-羟基人参二醇之外,尚分离到(20R.25S)-12β,25-环氧20,26-环达玛烷-2α,3β-二醇一新化合物.其结构经波谱分析和X射线衍射鉴定,确证20-C和25-C手性中心的绝对构型分别为R和S型.     

Structure elucidation and complete NMR spectral assignments of two new dammarane-type tetraglycosides from Panax quinquefolium

Two new saponins were isolated from leaves of Panax quinquefolium and their structures were elucidated as 3beta, 12beta, 20S-trihydroxy-25-methoxydammar-23-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[alpha-L-arabinopyranosyl(1-->6)]-beta-D-glucopyranoside (1) and 3beta, 20S-dihydroxy-12beta, 23R-epoxydammar-24-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[beta-D-xylopyanosyl(1-->6)]-beta-D-glucopyranoside (2) on the basis of (1)D and (2)D NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC, TOCSY, HMBC, and NOESY), ESI-MS spectrometry and chemical methods.     

Enzymatic preparation of ginsenosides Rg2, Rh1, and F1

During investigation of the hydrolysis of a protopanaxatriol-type saponin mixture by various glycoside hydrolases, crude preparations of beta-galactosidase from Aspergillus oryzae and lactase from Penicillium sp. were found to produce two minor saponins, ginsenoside Rg(2) [6-O-(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl)-20(S)-protopanaxatriol] and ginsenoside Rh(1) (6-O-beta-D-glucopyranosyl-20(S)-protopanaxatriol), respectively, in high yields. Moreover, a naringinase preparation from Penicillium decumbens readily gave an intestinal bacterial metabolite, ginsenoside F(1) (20-O-beta-D-glucopyranosyl-20(S)-protopanaxatriol), as the main product, with a small amount of 20(S)-protopanaxatriol from a protopanaxatriol-type saponin mixture. Also, a hesperidinase from Penicillium sp. selectively hydrolyzed ginsenoside Re into ginsenoside Rg(1). This is the first report on the enzymatic preparation of minor saponins, ginsenosides Rg(2) and Rh(1), and of an intestinal bacterial metabolite, ginsenoside F(1), with high efficiency from a protopanaxatriol-type saponin mixture.     

Studies on absorption, distribution, excretion and metabolism of ginseng saponins. VIII. Isotope labeling of ginsenoside Rb2.

To clarify the pharmacokinetics of absorption, distribution and excretion of ginsenoside Rb2 (Rb2), one of the major saponins of the root of Panax ginseng, following oral administration to rats, a tritium (3H) labeling of Rb2 was examined. The C-12 position of Rb2 was labeled with 3H-sodium borohydride (3H-NaBH4) and 12-3H Rb2 and 12-3H-epi Rb2 was synthesized. This method of specific position labeling of Rb2 may be applicable to other ginsenosides. In the near future, the pharmacokinetics of Rb2 in rats may be clarified with 3H labeled Rb2.     

土贝母化学成分的研究 IV: 土贝母苷乙, 丙, 丁的结构

从葫芦科(Cucurbitaceae)植物假贝母(Bolbostemma paniculatum [Maxin]Franquet)鳞茎中分离到三个土贝母苷乙, 丙, 丁. 用光谱分析和化学降解鉴定了它们的结构, 土贝母乙, 丙是二个新的大环三萜皂苷, 土贝母丁是3-O-[α-L-吡喃阿拉伯糖基(1→2)-β-D-吡喃葡糖基]-3β, β-18, 20, 26-五羟-(20S)-达马-24-烯, 是从植物假贝母中分离到的仅有四环三萜.     

Three new pentacyclic triterpenes and some flavonoids from the fruits of an Indian Ayurvedic plant Dendrophthoe falcata and their estrogen receptor binding activity

Extensive chromatographic screening of extracts of the fruits of the Indian Ayurvedic plant, Dendrophthoe falcata, resulted in the isolation of three new triterpenes, 3beta-acetoxy-1beta-(2-hydroxy-2-propoxy)-11alpha-hydroxy-olean-12-ene (1), 3beta-acetoxy-11alpha-ethoxy-1beta-hydroxy-olean-12-ene (2) and 3beta-acetoxy-1beta-hydroxy-11alpha-methoxy-olean-12-ene (3) along with nine known compounds, 3beta-acetoxy-1beta,11alpha-dihydroxy-olean-12-ene (4), 3beta-acetoxy-1beta,11alpha-dihydroxy-urs-12-ene (5), 3beta-acetoxy-urs-12-ene-11-one (6), 3beta-acetoxy-lup-20(29)-ene (7), 30-nor-lup-3beta-acetoxy-20-one (8), (20S)-3beta-acetoxy-lupan-29-oic acid (9), kaempferol-3-O-alpha-L-rhamnopyranoside (10), quercetin-3-O-alpha-L-rhamnopyranoside (11), and gallic acid (12). The structures of these compounds were determined using 1D and 2D NMR and high resolution electrospray mass spectrometry. These compounds were assayed for binding to estrogen receptors-alpha and beta and kaempferol-3-O-alpha-L-rhamnopyranoside (10) was found to be a ligand for both receptors with greater affinity for beta. The triterpenes (1-9) are reported for the first time in the genus Dendrophthoe and assumes taxonomic significance.     

反相高效液相色谱法测定人参皂甙Compound-K的含量

人参皂甙compound-K(C-K)在人参中的含量极低,但它是其他含量较高的人参皂甙Rb1和Rb2等在人体肠道内的主要 降解产物和最终吸收形式,具有很高的生物活性。采用反相高效液相色谱法测定了人参总皂甙发酵液中C-K的含量。色谱 条件为:反相C18柱;乙腈-水(体积比为48∶52)溶液为流动相,流速1.0 mL/min;紫外检测波长203 nm;柱温35 ℃;外标法 定量。结果表明:C-K的质量浓度为0.05~0.8 g/L时,其峰面积与质量浓度具有良好的线性关系,相关系数为0.9998。方法 的检测限(S/N=3)为2.5 mg/L,峰面积测定值的相对标准偏差(n=6)为2.20%。测定栽培人参总皂甙及三七茎叶总皂甙微生 物发酵液中C-K的平均加标回收率(n=3)分别为98.6%和99.7%。该方法快速简便,准确可靠,可用于C-K的制备研究及药物 开发。     

Marked production of ginsenosides Rd, F2, Rg3, and compound K by enzymatic method

The hydrolysis of protopanaxadiol-type saponin mixture by various glycoside hydrolases was examined. Among these enzymes, crude preparations of lactase from Aspergillus oryzae, beta-galactosidase from A. oryzae, and cellulase from Trichoderma viride were found to produce ginsenoside F(2) [3-O-(beta-D-glucopyranosyl)-20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol], compound K [20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol], and ginsenoside Rd {3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]-20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol}, respectively, from protopanaxadiol-type saponin mixture in large quantities. Moreover, the crude preparation of lactase from Penicillium sp. having a high producing activity of ginsenoside Rh(1) (6-O-beta-D-glucopyranosyl-20(S)-protopanaxatriol) from protopanaxatriol-type saponin mixture gave ginsenoside Rd as a main product, ginsenoside Rg(3) {3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]-20(S)-protopanaxadiol}, and compound K from protopanaxadiol-type saponin mixture. The hydrolytic pathways of ginsenosides Rb(1), Rb(2), and Rc to ginsenosides Rd, Rg(3), and F(2), and compound K by crude preparations of four glycoside hydrolases were also studied. This is the first report on the enzymatic preparation of an intestinal bacterial metabolite, ginsenoside F(2), in quantity, and a considerable amount of a minor saponin, ginsenoside Rg(3), from a protopanaxadiol-type saponin mixture.     

Determination of Saponins in Leaf of Panax Ginseng C. A. Mey. by High Performance Liquid Chromatography

A high performance liquid chromatography(HPLC) with UV detection was established for simultaneous determination of saponins in the leaf of Panax ginseng C. A. Mey. Nine ginsenosides(Rb1,Rb2,Rb3,Rc,Rd,F1,F2,F3,F5) and notoginsenoside Fe(NFe) were studied. Among the saponins,the ginsenosides F1,F2,F3,F5 and NFe were determined by HPLC-UV method for the first time. The determination of the ginsenosides via the HPLC-UV method was performed on a reversed-phase C18 column with gradient elution in 40 min. The line...     

云南重楼中的新甾体皂苷

从云南重楼Paris polyphylla Sm. var. yunnanensis(France. )Hand.-Mazz.的干燥根茎中分离鉴定了4个甾体皂苷(1~4), 其中化合物1是新化合物, 采用波谱技术鉴定其结构为24-O-β-D-吡喃半乳糖基-(23S,24S)-螺甾-5, 25(27)-二烯-1β,3β,23,24-四醇-1-O-β-D-吡喃木糖基(1→6)-β-D-吡喃葡萄糖基(1→3)[α-L-吡喃鼠李糖基(1→2)]-β-D-吡喃葡萄糖苷.     

Cucurbitane triterpenoids from Momordica charantia

Three new cucurbitane-type triterpenoid saponins, 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,22(S),23(S)-triol-3-O-beta-D-glucopyranoside (1), 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,22(S),23(S)-triol-3-O-beta-D-allopyranoside (2), and 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,19(R), 22(S),23(S)-tetraol-3-O-beta-D-allopyranoside (3), named momordicoside M, N, and O, respectively, along with one known saponin momordicoside L (4), were isolated from the fresh fruits of Momordica charantia. The structures of these saponins were elucidated on the basis of chemical properties and spectral data.     

Determination of clorazepate and its major metabolites in blood and urine by electron capture gas-liquid chromatography.

A sensitive and specific blood level method employing differential extraction was developed for the determination of clorazepate and its N-desmethyldiazepam metabolite by electron capture gas-liquid chromatography (GLC-ECD). The assay requires the initial extraction of N-desmethyldiazepam, the major metabolite, into benzene-methylene chloride (90:10) from the biological sample made alkaline with 0.1 N NaOH. The samples is then acidified with 2 N HCl to decarboxylate clorazepate to N-desmethyldiazepam, which is then extracted into benzene-methylene chloride (90:10) after adjusting the pH to 12.8 with NaOH. The two extracts are evaporated and the residues are dissolved in benzene which contains griseofulvin as the reference standard. These solutions are assayed by GLC-ECD. The overall recovery and sensitivity limit of the assay for clorazepate is 60+/-5% (S.D.) and 4.0 ng/ml blood, respectively, while that for N-desmethyldiazepam is 95+/-5% (S.D.) and 4.0 ng/ml blood, respectively. The urinary excretion of clorazepate was determined by the measurement of the levels of N-desmethyldiazepam and oxazepam, the major urinary metabolites of clorazepate, both prior to and after enzymatic deconjugation. These methods were applied to the measurement of clorazepate and its metabolites in blood and urine following a single 15-mg dose of clorazepate dipotassium.     

Chemical modification of usnic acid 1. Reaction of (+)-usnic acid with perfluoroolefins

The reactions of the natural lichen metabolite, (+)-usnic acid, with a series of commercially available polyfluoroolefins (tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, perfluoro-2-methylpent-2-ene, and 1,2-dichlorooctafluorocyclohex-1-ene) afford its 7-O-polyfluoroalkyl and perfluorovinyl ethers. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1198–1202, June, 2007.     

Asymmetric aminocarbonylation of iodoalkenes in the presence of α-phenylethylamine as an N-nucleophile

Iodoalkenes, such as 2-iodo-bornene, 17-iodoandrost-16-ene, 3-methoxy-17-iodoestra-1,3,5(10),16-ene, 3β-hydroxy-20-iodopregna-5,20-diene and 3β-hydroxy-12-iodo-5α,25R-spirost-11-ene were aminocarbonylated with enantiomerically pure and racemic α-phenylethylamine as the N-nucleophile in the presence of palladium(0) catalysts. Monodentate and bidentate (chiral and achiral) phosphines were used as ligands in the catalytic system. All diastereoisomers of the corresponding carboxamides were characterised as pure stereoisomers using both α-phenylethylamine and iodoalkene in enantiomerically pure form. The diastereoisomers were obtained in moderate to high yields in a chemoselective reaction, i.e., carboxamides due to single carbon monoxide insertion were formed exclusively, with no double CO insertion leading to 2-ketocarboxamides. Diastereoselectivities of the aminocarbonylation were investigated using the N-nucleophile in racemic form by the systematic variation of the catalyst.     

Studies on absorption, distribution, excretion and metabolism of ginseng saponins. V. The decomposition products of ginsenoside Rb2 in the large intestine of rats

The decomposition of ginsenoside Rb2 (Rb2) in the rat large intestine after oral administration was investigated in detail. A part of Rb2 was decomposed and six decomposition products (I-VI) were observed on thin-layer chromatogram. Among them, five products (I-V) were isolated, and identification of these compounds was done by carbon-13 nuclear magnetic resonance (13C-NMR). On the basis of 13C-NMR analysis, these compounds were identified as ginsenoside Rd (I), 3-O-beta-D-glucopyranosyl-20-O- [alpha-L-arabinopyranosyl(1----6)-beta-D-glucopyranosyl]-20(S)- proto-panaxadiol (II), ginsenoside F2 (III), 20-O-[alpha-L-arabinopyranosyl(1----6)-beta-D-glucopyranosyl]-20(S )- protopanaxadiol (IV), and compound K (V), respectively.     

Asymmetric synthesis of organoelemental analogs of natural compounds. 7. (2R,3S)-2-amino-3-hydroxy-5-phosphonovaleric acid

The reaction of the Ni(II) complex of the Schiff base of glycine with (S)-2-N-(N¹-benzylprolyl)-o-aminobenzophenone with diethyl-3-bromo-2-hydroxypropyl phosphonate yields the corresponding complex from which (2R, 3S)-2-amino-3-hydroxy-5-phosphonovaleric acid is separated with HCl.See [1] for Communication 6.Institute of Bioorganic Chemistry and Petrochemistry, Ukrainian Academy of Sciences, 252660 Kiev; N. A. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1172–1175, May, 1992.