Tropane alkaloids from Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae)

Six tropane alkaloids were isolated from the Sri Lankan endemic plant Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae) and structurally elucidated by NMR and MS measurements. Three of them, erythrozeylanines A [1R,3R,5S,6R-6-acetoxy-3-(3',4',5'-trimethoxybenzoyloxy)tropane], B [cis-3 beta-(cinnamoyloxy)tropane], and C [cis-6 beta-acetoxy-3 alpha-(cinnamoyloxy)tropane] are new, whereas the others have already been found in other Erythroxylum species. For the first time, the absolute configuration of a tropane alkaloid (erythrozeylanine A) has been determined by quantum chemical CD calculations.     

Isolation and structure of a cytotoxic epoxy sterol from the marine mollusc Planaxis sulcatus

A novel epoxy sterol isolated from the marine mollusc Planaxis sulcatus has been identified as 9 alpha,11 alpha-epoxycholest-7-ene-3 beta,5 alpha,6 beta-triol by spectrometric methods.     

Tropane alkaloids from Erythroxylum caatingae Plowman

Three tropane alkaloids, 1-3, were isolated from Erythroxylum caatingae, i.e., 6β-benzoyloxy-3α-[(4-hydroxy-3,5-dimethoxybenzoyl)oxy]tropane (1), a new tropane alkaloid, along with the known alkaloids 3α,6β-dibenzoyloxytropane (2) and 6β-benzoyloxy-3α-[(3,4,5-trimethoxybenzoyl)oxy]tropane (catuabine B; 3). Their structures were determined by 2D- ((1) H and (13) C) NMR. By LC/ESI-MS/MS analysis of the fractions of alkaloids 1-3, it was possible to detect five more alkaloids, 4-8, two of these, 4 and 8, possibly being new natural products. X-Ray crystallography of the chloride derivate of 1, i.e., 6β-benzoyloxy-3α-(4-hydroxy-3,5-dimethoxybenzoyloxy)tropane hydrochloride (1a) confirmed the structure of 1. Cytotoxicity was tested against the cell lines HEp-2, NCI-H292, and KB for the MeOH extract and alkaloid 3, and antitumor activity was tested against Sarcoma 180 only for the MeOH extract.     

GC-MS investigation of tropane alkaloids in Datura stramonium

Alkaloids, GS-MS, Datura stramonium The alkaloid spectrum in roots, leaves and seeds of Datura stramonium L. was investigated by GC-MS. Twenty-nine tropane alkaloids are detected. Twelve of them are new constituents for the species and the two tropane esters 3-(3'-acetoxytropoyloxy)tropane (21) and 3-(2'-hydroxytropoyloxy)tropane (26) are described for the first time.     

A new ceramide from Suillus luteus and its cytotoxic activity against human melanoma cells

A new phytosphingosine-type ceramide, suillumide (1), was isolated from the EtOH extract of the basidiomycete Suillus luteus (L.) S. F. Gray, along with ten known compounds: ergosta-4,6,8(14),22-tetraen-3-one, ergosterol, ergosterol peroxide, suillin, (E)-3,4,5-trimethoxycinnamic alcohol, 5 alpha,6 alpha-epoxyergosta-8,22-diene-3beta,7 beta-diol, (R)-1-palmitoylglycerol, ergosta-7,9(11),22-triene-3beta,5 alpha,6 beta-triol, cerevisterol, and 4-hydroxybenzoic acid. The structure of 1 was determined on the basis of spectroscopic and mass-spectrometric analyses, as well as by chemical methods. Compound 1 and its synthetic diacetyl derivative 2 were tested for their cytotoxic activities against the human melanoma cell line SK-MEL-1. Both drugs showed IC(50) values of ca. 10 microM after 72 h of exposure.     

Comparative study of the alkaloids in tribe Datureae and their chemosystematic significance

Sixty-six tropane alkaloids from crude leaf and root alkaloid mixtures of 12 different species and their varieties and subspecies from tribe Datureae were determined by GC–MS. The alkaloids 3β-hydroxy-6β-acetoxytropane, 3-propionyloxy-6-hyroxytropane, 3β-hydroxy-6β-tigloyloxytropane, 3β-tigloyloxy-6β-acetoxytropane and 3-tigloyloxy-7-isobutyryloxytropane are new reported tropane alkaloids.     

Erythroxylon (Erythroxylaceae) on Socotra

Erythroxylon socotranum , sp. nov., is described from limestone rocks on southwestern Socotra (Yemen). The species is the first representative of Erythroxylaceae to be known from Socotra and from South-West Asia in general.     

乌檀的化学成分研究

从珍稀药用植物乌檀(Nauclea officinalis)的枝叶中分离得到1个甾醇类、3个三萜类、2个酚类和1个生物碱类化合物。通过光谱分析,分别鉴定为豆甾-4-烯-3-酮(1)、铁冬青酸(2)、常春藤皂苷元(3)、3-羰基奎诺瓦酸(4)、2,5-二甲氧基苯甲酸(5)、3,4,5-三甲氧基苯甲酸(6)和Strictosamide(7)。7个化合物均是首次从乌檀中得到。     

A new tropane alkaloid and other constituents of Erythroxylum rimosum (Erythroxylaceae)

A new tropane alkaloid, named the 7β-acetoxy-3β,6β-dibenzoyloxytropane (1), was isolated from a methanol extract of Erythroxylum rimosum O.E. Schulz leaves. Other known compounds were detected, including quercetin, kaempferol-3-O-α-l-arabinofuranoside, (+)-catechin, epicatechin, quercetin-3-O-α-arabinofuranoside, quercetin-3-O-α-arabinopyranoside, quercetin-3-O-β-arabinopyranoside, quercetin-3-β-glucopyranoside, kaempferol, quercetin-3-O-β-galactopyranoside, β-sitosterol, α-amyrin, β-amyrin, and the ester derivatives of these two amyrins. Compound 1 exhibited weak inhibition of acetylcholinesterase. Structural identification was performed using IR, ESIHRMS and one- and two-dimensional NMR data analyses and confirmed by comparison with literature data.     

In vitro organogenesis and alkaloid accumulation in Datura innoxia

The kinetics of tropane alkaloids accumulation in different organs such as roots, leaves, stems, flowers and seeds of Datura innoxia was investigated by GC-MS. Twenty-six tropane alkaloids were detected. The ester derivatives of tropine (3alpha-tigloyloxytropine and 3-tigloyloxy-6-hydroxytropine) are the major compounds. Undifferentiated callus were established from the stem explants of Datura innoxia using Murashige and Skoog (MS) medium supplied with 6-benzylaminopurine (BA, 1 mg l(-10) and indole-3-acetic acid (IAA, 0.5 mg l(-1)) in combination for 6 weeks. Callus differentiation was initiated by subculture onto solid MS medium, free from hormones, for more than 10 months. Initially, shoots were formed after four weeks from subculture. Further subculturing in basal MS medium without growth regulators initiated the rooting of a shooty callus after 6 weeks. Investigation of the alkaloid content of the unorganized and organized callus revealed that callus (either green or brown) yielded only trace amounts of alkaloids. On the other hand, re-differentiated shoots contained mainly scopolamine while re-differentiated roots biosynthesized hyoscyamine as the main alkaloid.     

Simultaneous determination of scopolamine, hyoscyamine and littorine in plants and different hairy root clones of Hyoscyamus muticus by micellar electrokinetic chromatography

Hyoscyamus muticus hairy root clones were established following infection with Agrobacterium rhizogenes strains A4, LBA-9402 and 15834 and with A. tumefaciens strain C58C1pRTGus104. The accumulation of tropane alkaloids hyoscyamine, littorine and scopolamine was evaluated by micellar electrokinetic capillary electrophoresis. Littorine was reported for the first time in these clones as well as in the roots of the intact plant and confirmed by collision induced dissociation-mass spectrometry. Tropane alkaloid content in hairy roots was compared with leaves and roots of normal plants at two vegetative stages. Significant differences appeared between the alkaloid contents of the different clones. In particular, all the hairy root clones and the roots of the intact plant produced 1.5-3 and 4.5-9 times more littorine than scopolamine, respectively. The only exception was clone KB7, carrying the h6h gene, which overproduced scopolamine. The aerial parts of H. muticus plants did not contain any littorine, thus indicating different transportation or translocation mechanisms of the various tropane alkaloids.     

Metabolism of cholestane-3 beta,5 alpha,6 beta-triol. II. Identification of two major neutral metabolites in the rat

Rats were given a single oral dose of cholestane-3beta,5alpha,6beta-triol-4-(14)C, and their feces were collected. The two major neutral metabolites were separated and isolated by use of solvent fractionation and chromatographic methods. The metabolites were identified as cholestane-3beta,5alpha-diol-6-one and a mixture of long-chain fatty acid esters of cholestane-3beta,5alpha,-6beta-triol. Cholestane-3beta,5alpha-diol-6-one was identified using thin-layer and gas-liquid chromatography, infrared spectroscopy, and the spectrum produced by reaction with 65% sulfuric acid. The mixed esters of cholestane-3beta,5alpha,6beta-triol were subjected to basic hydrolysis, and the steroid moiety was identified using the same techniques employed for cholestane-3beta,5alpha-diol-6-one. The fatty acids were analyzed by gas-liquid chromatography of their methyl esters.     

Chemotaxonomy of the pantropical genus Merremia (Convolvulaceae) based on the distribution of tropane alkaloids

The occurrence and distribution of tropane and biogenetically related pyrrolidine alkaloids in 18 Merremia species of paleo-, neo-, and pantropical occurrence have been studied. The extensive GC-MS study included members of almost all sections of the genus and has been carried out with epigeal vegetative parts as well as with roots. It comprises altogether 74 tropanes and 13 pyrrolidines including nicotine. Along with datumetine known already from a solanaceous species, the study led to the isolation (from M. dissecta and M. guerichii, respectively) and structure elucidation (spectral data) of four novel 3alpha-acyloxytropanes, merresectines A-D: 3alpha-(4-methoxybenzoyloxy)nortropane (A), 3alpha-kurameroyloxytropane (B), 3alpha-nervogenoyloxytropane (C), 3alpha-[4-(beta-D-glucopyranosyloxy)-3-methoxy-5-(3-methyl-2-butenyl)benzoyloxy]tropane (beta-d-glucoside of D). Moreover, the novel 3alpha,6beta-di-(4-methoxybenzoyloxy)tropane (merredissine) has been isolated from M. dissecta and structurally elucidated. In addition the structures of datumetine and merresectine A could be confirmed by synthesis. Spectral data for two known 3alpha-acyloxytropanes (merresectine E beta-D-glucoside, 4'-dihydroconsabatine) and one known 3beta-acyloxytropane (concneorine) are documented for the first time. The structures of three further merresectines (F-H) have been determined by mass spectrometry. Furthermore, the linkage (2',3- and 2',4-, respectively) of two position isomer N-methylpyrrolidinylhygrines was proven by synthesis. The results of the study contribute to the solution of infrageneric taxonomic problems. Whereas all species yield pyrrolidine alkaloids without suitably differentiating results the diverging occurrence of tropane alkaloids leads to three groups of sections: (1) taxa free of tropanes, (2) taxa with simple tropanes, and (3) taxa with merresectines in addition to simple tropanes.     

Insight into the molecular evolution of two tropinone reductases

In tropane alkaloid biosynthesis, two tropinone reductases produce different stereoisomers from a common substrate, tropinone. The two enzymes share 64% of identical amino acids, and highly homologous proteins with variable substrate-binding residues have also been found in tropane alkaloid non-producing species. This exemplifies a simple evolutionary process that plants have taken to acquire a new secondary metabolic pathway.     

三丫苦的化学成分研究

采用硅胶柱层析从三丫苦的乙酸乙酯萃取物中分离得到6种化合物,经波谱分析鉴定为4,7-二甲氧基呋喃喹啉生物碱(1)、顺式-3,4,5-三羟基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(2)、3-羟基-4-乙氧基-5,7-二甲氧基-6-乙酰-2,2-二甲基色烷(3)、3,5-二羟基-4-乙氧基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(4)、异吴茱萸酮酚(5)和异吴茱萸酮酚甲醚(6)。所有化合物均首次从该植物的根部分离得到。     

Antimalarial constituents from Nauclea orientalis (L.) L

Bioassay-guided fractionation of the antimalarial-active CHCl3 extract of the dried stem of Nauclea orientalis (L.) L. (Rubiaceae) has resulted in the isolation of two novel tetrahydro-beta-carboline monoterpene alkaloid glucosides, naucleaorine (= (16alpha,17beta)-3,14:15,20-tetradehydro-16-ethenyl-17-(beta-D-glucopyranosyloxy)-19alpha-methoxyoxayohimban-21-one; 1) and epimethoxynaucleaorine (2), as well as the known compounds, strictosidine lactam (= (15beta,16alpha,17beta)-19,20-didehydro-16-ethenyl-17-(beta-D-glucopyranosyloxy)oxayohimban-21-one; 3), 3,4,5-trimethoxyphenol (4), 3alpha-hydroxyurs-12-en-28-oic acid methyl ester (5), 3alpha,23-dihydroxyurs-12-en-28-oic acid (6), 3alpha,19alpha,23-trihydroxyurs-12-en-28-oic acid methyl ester (7), and oleanolic acid (8). Compounds 1, 2, 6, and 8 showed moderate in vitro activities against Plasmodium falciparum. Their structures and configurations were elucidated by spectroscopic methods including 1D- and 2D-NMR analyses.     

Identification of a new Sertoli cell metabolite of testosterone: 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol, by HPLC and GC-MS

Testosterone metabolism by isolated rat Sertoli cells cultured in vitro was investigated using HPLC and GC-MS techniques. Monolayer cultures of Sertoli cells (greater than 90% pure and free of Leydig cells) were incubated for 3-day periods with a stable labeled [2,2,4,6,6-d5]testosterone prepared and used in a 1:1 proportion with unlabeled testosterone as the substrate (5 X 10(-7)M). After incubation, the metabolites were extracted from the media and reacted with oestradiol-antibodies. The antibody-bound components were separated on reverse phase HPLC and the fraction corresponding to oestradiol was analyzed by GC-MS in the form of TMS-ether. One of the metabolites whose mass spectrum contained d0 + d5 species was detected and interpreted to be a triol with a mol. wt of 308. Mass spectra data indicated that this testosterone metabolite is one of the sixteen possible isomers of 3,16,17-trihydroxy androstane. This substance was identified based on the Vm value (27.81) closely resembling that of 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol TMS-ether (Vm reported = 27.78) [1] and when compared directly with synthesized compounds [2-3]. Recently we have demonstrated that similar Sertoli cell preparations contain two 16 alpha-hydroxylases by their ability to convert oestradiol to oestriol [4] and 5 alpha-androstane-3 alpha,17 beta-diol to 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol [3], where the former conversion is not affected by FSH, the latter is significantly stimulated by the presence of FSH. Presence of this new product represents the first example of testosterone conversion to 5 alpha-androstane-3 alpha,16 alpha,17 beta-triol and confirms our previous observation that 16 alpha-hydroxylation of 5 alpha-reduced androgens can occur in the rat testis.     

The degradation of cholic acid by Pseudomonas sp. N.C.I.B. 10590 under anaerobic conditions.

The bacterial degradation of cholic acid under anaerobic conditions by Pseudomonas sp. N.C.I.B. 10590 was studied. The major unsaturated neutral compound was identified as 12 beta-hydroxyandrosta-4,6-diene-3,17-dione, and the major unsaturated acidic metabolite was identified as 12 alpha-hydroxy-3-oxochola-4,6-dien-24-oic acid. Eight minor unsaturated metabolites were isolated and evidence is given for the following structures: 12 alpha-hydroxyandrosta-4,6-diene-3,17-dione, 12 beta,17 beta-dihydroxyandrosta-4,6-dien-3-one, 12 beta-hydroxyandrosta-1,4,6-triene-3,17-dione, 12 beta,17 beta-dihydroxyandrosta-1,4,6-trien-3-one, 12 beta-hydroxyandrosta-1,4,6-triene-3,17-dione, 12 beta,17 beta-dihydroxyandrosta-1,4,6-trien-3-one, 12 alpha-hydroxyandrosta-1,4-diene-3,17-dione, 3-hydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione, 3,12-dioxochola-4,6-dien-24-oic acid and 12 alpha-hydroxy-3-oxopregna-4,6-diene-20-carboxylic acid. In addition, a major saturated neutral compound was isolated and identified as 3 beta,12 beta-dihydroxy-5 beta-androstan-17-one, and the only saturated acidic metabolite was 7 alpha,12 alpha-dihydroxy-3-oxo-5 beta-cholan-24-oic acid. Nine minor saturated neutral compounds were also isolated, and evidence is presented for the following structures: 12 beta-hydroxy-5 beta-androstane-3,17-dione, 12 alpha-hydroxy-5 beta-androstane-3,17-dione, 3 beta,12 alpha-dihydroxy-5 beta-androstan-17-one, 3 alpha,12 beta-androstan-17-one, 3 alpha,12 alpha-dihydroxy-5 beta-androstan-17-one, 5 beta-androstane-3 beta,12 beta,17 beta-triol, 5 beta-androstane-3 beta,12 alpha,17 beta-triol, 5 beta-androstane-3 alpha,12 beta,17 beta-triol and 5 beta-androstane-3 alpha,12 alpha,17 beta-triol. The induction of 7 alpha-dehydroxylase and 12 alpha-dehydroxylase enzymes is discussed, together with the significance of dehydrogenation and ring fission under anaerobic conditions.     

Tropane alkaloids from Latua pubiflora

Four known tropane alkaloids were isolated from the leaves of the endemic Chilean plant Latua pubiflora (Solanaceae). For the first time; 3alpha-cinnamoyloxitropane and apoatropine are reported in this plant. Scopolamine and hyoscyamine were previously reported.     

Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3beta,5alpha,6beta-triol

Incubation of [4-(14)C]cholesteryl palmitate with the 12,000 g supernatant fraction of adult rat brain fortified with an NADPH-generating system and beta-mercaptoethylamine resulted in formation (2-5%) of more polar metabolites characterized as a mixture of cholesterol-5,6-epoxides. Under extended incubation conditions, cholestane-3beta-5alpha-6beta-triol was isolated as the major end product of the incubations. Free [4-(14)C]cholesterol incubated under similar conditions was not oxidized, whereas oxidation of [4-(14)C]cholesteryl palmitate appeared to be dependent upon hydrolysis of the ester by the rat brain microsomal subcellular fraction. Elimination of the NADPH-generating system or the addition of EDTA to the incubation mixture inhibited epoxide formation, suggesting that the products are derived from an NADPH-dependent enzymatic lipoperoxidation mechanism. The in vitro conversion of [4-(14)C]cholesterol-5alpha,6alpha-epoxide to cholestane-3beta,5alpha,6beta-triol was also demonstrated in rat brain subcellular fractions in the absence of added cofactors.