Ent-kaurane diterpenoid glycosides from the leaves of Cussonia racemosa, a Malagasy endemic plant

Six new ent-kaurane diterpenoid glycosides, cussoracosides A (3), B (4), C (5), D (6), E (7), and F (8) were isolated from the dried leaves of Cussonia racemosa, along with two known compounds identified as beta-D-glucopyranosyl ent-16beta,17-dihydroxykauran-19-oate (1) and paniculoside IV (2). The structures of these new compounds were deduced on the basis of chemical and spectroscopic evidence.     

New triterpene glucosides from the roots of Rosa laevigata Michx

Two new ursane-type triterpene glucosides, 2alpha,3alpha,24-trihydroxyurs-12,18-dien-28-oic acid beta-D-glucopyranosyl ester (1) and 2alpha,3alpha,23-trihydroxyurs-12,19(29)-dien-28-oic acid beta-D-glucopyranosyl ester (2), were isolated from the roots of Rosa laevigata, together with three known compounds: 2alpha,3beta,19alpha-trihydroxyurs-12-en-28-oic acid beta-Dglucopyranosyl ester (3), 2alpha,3alpha,19alpha-trihydroxyurs-12-en-28-oic acid beta-D-glucopyranosyl ester (4) and 2alpha,3beta,19alpha,23-tetrahydroxyurs-12-en-28-oic acid beta-D-glucopyranosyl ester (5). The structures of new compounds were established on the basis of detailed 1D and 2D NMR spectroscopic analyses. Compounds 2 and 5 exhibited modest in vitro antifungal activities against Candida albicans and C. krusei.     

Synthesis of 19-oxygenated 4beta,5beta-epoxy derivatives of 16alpha-hydroxyandrostenedione as mechanistic and catalytic probes for aromatase reaction

4Beta,5beta-epoxy derivatives of 16alpha-hydroxyandrostenedione (2), one of the natural substrates for aromatase, and its 19-oxygenated compounds 4 and 5 were synthesized as mechanistic and catalytic probes for the enzyme reaction. Treatment of 16alpha-bromoandrostenedione (13) or its 19-hydroxy analog 19 which was prepared from 3beta-hydroxy-19-(tert-butyldimethylsiloxy)androst-5-en-17-one (16) in three steps, with H2O2 and NaOH followed by controlled alkaline hydrolysis with NaOH in aqueous pyridine stereospecifically yielded 4beta,5beta-epoxy-16alpha-ol 15 or 4beta,5beta-epoxy-16alpha,19-diol 22, respectively. Oxidation of 16beta-bromo-4beta,5beta-epoxy-19-ol 21 with pyridinium dichromate followed by controlled alkaline hydrolysis produced 4beta,5beta-epoxy-16alpha-hydroxy-19-al 24.     

Synthesis of deuterium-labeled 16 alpha,19-dihydroxy C19 steroids as internal standards for gas chromatography-mass spectrometry.

[2 beta,7,7,16 beta-2H4]16 alpha,19-Dihydroxyandrost-4-ene-3,17-dione (14) and [7,7,16 beta-2H3]3 beta,16 alpha,19-trihydroxyandrost-5-en-17-one (16), with high isotopic purity, respectively, were synthesized from unlabeled 3 beta-(tert-butyldimethylsiloxy)-androst-5-ene-17 beta-yl acetate (1). The deuterium introduction at C-7 was carried out by reductive deoxygenation of the 7-keto compound 3 with dichloroaluminum deuteride and that at C-2 beta and/or C-16 beta by controlled alkaline hydrolysis of 16-bromo-17-ketone 11 or 12 with NaOD in D2O and pyridine. [7,7-2H2]3 beta-Hydroxyandrost-5-en-17-one (6), obtained from compound 1 by a five-step sequence, was converted to compound 14 or 16 by an eight-step or seven-step sequence, respectively. The labeled steroids 14 and 16 are useful as internal standards for gas chromatography-mass spectrometry analysis of the endogenous levels.     

Three new triterpene saponins from the seeds of Aesculus chinensis

Three new triterpenoid saponins were isolated from the seeds of Aesculus chinensis, and characterized as 22-tigloylprotoaescigenin 3-O-[beta-D-glucopyranosyl (1-->2)] [beta-D-glucopyranosyl (1-->4)]-beta-D-glucopyranosiduronic acid (escin IVg, 1), 22-angeloylprotoaescigenin 3-O-[beta-D-glucopyranosyl (1-->2)] [beta-D-glucopyranosyl (1-->4)]-beta-D-glucopyranosiduronic acid (escin IVh, 2) and 16-angeloyl-21-acetylprotoaescigenin 3-O-[beta-D-glucopyranosyl (1-->2)] [beta-D-glucopyranosyl (1-->4)]-beta-D-glucopyranosiduronic acid (escin VIb, 3), together with two known compounds, escin IIIa (4) and desacylescin 1 (5). Their structures were established on the basis of spectroscopic and chemical evidence.     

Synthesis of 16 alpha-hydroxyandrost-4-ene-3,17,19-trione and 3 beta, 16 alpha-dihydroxyandrost-5-ene-17,19-dione; potential intermediates of estriol biosynthesis

16 alpha-Hydroxyandrost-4-ene-3,17,19-trione (10) was synthesized from the 16 alpha-hydroxy-6 beta,19-epoxy-17-one 3 via protection of the 16 alpha-hydroxy function as its tert-butyldimethylsilyl ether or acetate. Reductive cleavage of the epoxy ring of the silyl ether 4 or the acetate 5 with zinc dust gave the 19-alcohol 6 or 7, which was treated with pyridinium dichromate or Jones reagent, respectively, and then hydrolyzed with diluted sulfuric acid, yielding the desired steroid 10. 3 beta,16 alpha-Dihydroxyandrost-5-ene-17,19-dione (14) was also synthesized from 5 alpha-bromo-3 beta,16 alpha-diacetoxy-6 beta, 19-epoxyandrostan-17-one (11) through the intermediates 12 and 13 with the 3 beta- and 16 alpha-hydroxy functions protected as their acetates in a reaction sequence similar to that above.     

Additional minor diterpene glycosides from Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, two additional new diterpenoid glycosides were isolated and their structures were characterized as 13-[(2-O-beta-glucopyranosyl-3-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (2) on the basis of extensive spectral data (NMR and MS) and chemical studies.     

Four new steroid constituents from the waste residue of fibre separation from Agave americana leaves

Three new steroidal saponins, named agamenosides H-J (1-3), and a new cholestane steroid agavegenin D (4) were isolated from the waste residue of fibre separation from Agave americana leaves, together with six known steroids. Structures of the new compounds 1-4 were deduced to be (22S,23S,24R,25S)-24-[(beta-D-glucopyranosyl)oxy]-5alpha-spirostane-3beta,6alpha,23-triol 6-O-beta-D-glucopyranoside (1), (22S,23S,24R,25S)-5alpha-spirostane-3beta,23,24-triol 24-O-beta-D-glucopyranoside (2), (22S,23S,25R,26S)-23,26-epoxy-5alpha-furostane-3beta,22,26-triol 26-O-beta-D-glucopyranoside (3), and (22S,25S)-5alpha-cholestane-3beta,16beta,22,26-tetrol (4), respectively, by means of spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of hydrolytic cleavage.     

Four new saponins from the root bark of Aralia elata

Four new saponins, 3-O-[beta-D-glucopyranosyl(1-->3)-alpha-L-arabinopyranosyl]-16a lpha-hydroxyoleanolic acid 28-O-beta-D-glucopyranosyl ester (called aralia-saponin I), 3-O-[beta-D-glucopyranosyl(1-->3)-alpha-L-arabinopyranosyl]-16a lpha-hydroxyhederagenin 28-O-beta-D-glucopyranosyl ester (aralia-saponin II), 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranosyl(1-->3)-alpha-L-+ ++arabinopyranosyl]-16alpha-hydroxyoleanolic acid 28-O-beta-D-glucopyranosyl ester (aralia-saponin III), 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-gucopyranosyl(1-->3)-beta -D-glucucopyranosyl]-16alpha-hydroxyoleanolic acid 28-O-beta-D-glucopyranosyl ester (aralia-saponin IV), were isolated from the root bark of Aralia elata (Miq.) Seem., together with nineteen known compounds including glycosides of (20S)-protopanaxadiol and (20S)-protopanaxatriol. Their structures were determined on the basis of chemical and spectroscopy methods.     

Terpenoids from Chloranthus multistachys

Two new diterpenoids, ent-17-hydroxyl-16beta-methoxyl-kauran-3-one (1) and ent-17-acetoxyl-16beta-methoxyl-kauran-3-one (2), along with nine known compounds (3-12), ent-17-hydroxyl-kaur-15-en-3-one (3), ent-3beta-acetoxyl-kaur-15-en-16beta, 17-diol (4), ent-kauran-3beta, 16beta, 17-triol (5), ent-3beta-acetoxyl-kauran-16beta, 17-diol (6), ent-kauran-16beta, 17-diol (7), abbeokutone (8), ent-17alpha-acetyl-16beta-hydroxyl- kauran-3-one (9), shizukaol F (10), cycloshizukaol A (11) and curcolonol (12), were isolated from Chloranthus multistachys (Chloranthaceae). Their structures were elucidated by spectroscopic spectra.     

Steroidal saponins from rhizomes of Tupistra wattii Hook. f

Chemical examination of the fresh rhizomes of Tupistra wattii HOOK. f. led to the isolation of three new steroidal saponins, wattoside G (1), H (2), and I (3), together with one known steroidal saponin, (25S)-1beta,3beta,4beta-trihydroxyspirotan-5beta-yl-O-beta-D-glucopyranoside (4). The structures of 1-3 were established to be (25R)-1beta,2beta,3beta,5beta-tetrahydroxyspirostan-4beta-yl-O-beta-D-xylopyranoside (1), (24S,25S)-24-[(beta-D-glucopyranosyl)oxy]-1beta,2beta,3beta,4beta,5beta,7beta-hexahydroxyspirostan-6-one (2), and (24S,25S)-1beta,3beta-dihydroxy-5beta-spirostan-24-yl-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (3) on the basis of detailed analyses of physical, chemical, and spectral data. The isolated compounds were evaluated for cytotoxic activity against the cancer cell line K562 in vitro.     

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.     

Total synthesis of methyl protodioscin: a potent agent with antitumor activity

Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.     

Improved synthesis and molecular modeling of 4beta,19-dihydroxyandrost-5-en-17-one,an excellent inhibitor of aromatase

4Beta,19-dihydroxyandrost-5-en-17-one (6) is an excellent competitive inhibitor of estrogen synthetase (aromatase). Alternate, improved synthesis of this inhibitor was established. Treatment of 19-(tert-butyldimethylsilyloxy)androst-4-en-17-one (8) with m-chloroperbenzoic acid gave a 1.4:1 mixture of 4alpha,5alpha-epoxide 9 and its 4beta,5beta-isomer 10. The mixture was reacted with diI. HClO4 in dioxane to produce principally 4beta,5alpha-diol 11 (80%) of which acetylation followed by dehydration with SOCl2 yielded 4beta,19-diacetoxy-5-ene compound 14 in good yield. Alkaline hydrolysis of diacetate 14 gave 4beta,19-diol 6. The minimum energy conformation of the powerfull aromatase inhibitor 6 was obtained with the PM3 method and compared with that of the structurally related diol steroid, 4-ene-5beta,19-diol 3, a weak competitive inhibitor.     

Chemical Constituents from Annona Glabra

A new kaurane diterpenoid, annoglabasin G (16α‐hydro‐19‐acetoxy‐ent‐kauran‐17‐al) ( 1 ), along with 27 compounds including 18 kaurane diterpenoids, 16β‐hydro‐ent‐kauran‐17‐oic acid ( 2 ), 16α‐hydro‐ent‐kauran‐17‐oic acid ( 3 ), 19‐nor‐ent‐kauran‐4α‐ol‐17‐oic acid ( 4 ), 16α‐hydro‐19‐ol‐ent‐kauran‐17‐oic acid ( 5 ), ent‐kaur‐16‐en‐19‐oic acid ( 6 ), 16α‐hydroxy‐ent‐kauran‐19‐oic acid ( 7 ), 16α,17‐dihydroxy‐ent‐kauran‐19‐oic acid ( 8 ), 16β,17‐dihydroxy‐ent‐kauran‐19‐oic acid ( 9 ), 16α‐hydro‐ent‐kauran‐17,19‐dioic acid ( 10 ), 16β‐hydroxy‐17‐acetoxy‐ent‐kauran‐19‐oic acid ( 11 ), 16β‐hydro‐17‐hydroxy‐ent‐kauran‐19‐al ( 12 ), 16α‐hydro‐17‐hydroxy‐ent‐kauran‐19‐al ( 13 ), 16β,17‐dihydroxy‐ent‐kauran‐19‐al ( 14 ), 16α‐hydro‐19‐al‐ent‐kauran‐17‐oic acid ( 15 ), 16α‐hydro‐17‐acetoxy‐ent‐kauran‐19‐al ( 16 ), 16α‐hydro‐19‐acetoxy‐ent‐kauran‐17‐oic acid ( 17 ), ent‐kaur‐15‐en‐19‐oic acid ( 18 ) and ent‐kaur‐15‐en‐17‐ol‐19‐oic acid ( 19 ); four acetogenins, annomontacin ( 20 ), annonacin ( 21 ), isoannonacinone ( 22 ) and squamocin ( 23 ); four steroids, β‐sitosterol ( 24 ), stigmasterol ( 25 ), β‐sitosteryl‐D‐glucoside ( 26 ) and stigmasteryl‐D‐glucoside ( 27 ) and one oxoaporphine, liriodenine ( 28 ), were isolated from the fresh fruits of Annona glabra. These compounds were characterized and identified by physical and spectral evidence.     

Two minor diterpene glycosides from the leaves of Stevia rebaudiana

Two new new diterpene glycosides, 13-[(2-O-(6-O-beta-D-glucopyranosyl)-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-glucopyranosyl-3-O-beta-D-fructofuranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (2) were isolated from the leaves of Stevia rebaudiana, along with the known steviol glycosides stevioside, rebaudiosides A-F and dulcoside A. The structures of the two new compounds were established on the basis of extensive 2D NMR (COSY, HSQC, and HMBC), MS and chemical studies.     

Terpenoids and phenolics from Plectranthus strigosus, bioactivity screening

Further studies on Plectranthus sp. (Lamiaceae) led to the isolation of terpenes and phenol esters from Plectranthus strigosus Benth. ent-16-Kauren-19-ol (1), ent-16-kauren-19-oic acid (2), xylopic acid (3), xylopinic acid (4), hinokiol (5), 4 beta,6 beta-dihydroxy-1 alpha,5 beta(H)-guai-9-ene (6) 4 beta,6 beta-dihydroxy-1 alpha,5 beta(H)-guai-10(14)-ene (7), mixtures of hexacosan-1,26-diol and octacosan-1,28-diol ferulate diesters (8), of esters from ferulic acid and fatty alcohols (9) and of esters from fatty acids and 2-(4-hydroxyphenyl)-ethanol (10) were for the first time isolated from this genus. Supplementary spectral data for 3,8 and parvifloron D (11) metabolites are also presented. A bioactivity study revealed herpetic inhibitory properties for (1) and (2), and antioxidant ability for (5) and (8) phenolic constituents.     

New coumarin-hemiterpene ether glucosides and a structurally related phenylpropanoic acid derivative from Artemisia armeniaca

Two new coumarin-hemiterpene ether glucosides, 4'-O-(beta-D-glucopyranosyl) desoxylacarol (1), and 5-O-(beta-D-glucopyranosyl) lacarol (2), were isolated from the methanolic extract of the aerial parts of Artemisia armeniaca Lam. Their structures were established by means of spectroscopic analysis including 1H- and 2D-NMR, HRESIMS, and acid hydrolysis. In addition, a structurally related phenylpropanoic acid derivative (3) was obtained in small amounts, and its structure tentatively assigned as 3-(4-hydroxy-3-methylbutoxy)-4-methoxy melilotic acid.     

Bioactive pentacyclic triterpenes from the stems of Combretum laxum

Two new triterpene glucosides, beta-D-glucopyranosyl 2alpha,3beta,24-trihydroxyolean- 12-en-28-oate and beta-D-glucopyranosyl 2alpha,3beta,23,24-tetrahydroxyurs-12-en-28-oate, in addition to nine known compounds belonging to three different triterpene classes (oleanane-, ursane- and lupane-type) have been isolated from the stems of a specimen of Combretum laxum growing in the "Pantanal" of the central-western region of Brazil. Among the known triterpenes, beta-D-glucopyranosyl 2alpha,3beta,6beta-trihydroxyolean-12-en-28-oate is reported for the first time in the Combretaceae, while bellericoside and asiatic acid are described for the first time in the genus Combretum. The structures of the isolated compounds have been established on the basis of spectral techniques (1D-, 2D-NMR and MS). Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei and Cryptococcus neoformans were also evaluated in this work.     

Detection of methandienone (methandrostenolone) and metabolites in horse urine by gas chromatography-mass spectrometry.

The metabolic transformation of methandienone (I) in the horse was investigated. After administration of a commercial drug preparation to a female horse (0.5 mg/kg), urine samples were collected up to 96 h and processed without enzymic hydrolysis. Extraction was performed by a series of solid-liquid and liquid-liquid extractions, thus avoiding laborious purification techniques. For analysis by gas chromatography-mass spectrometry, the extracts were trimethylsilylated. Besides the parent compound I and its C-17 epimer II, three monohydroxylated metabolites were identified: 6 beta-hydroxymethandienone (III), its C-17 epimer (IV) and 16 beta-hydroxymethandienone (V). In addition, three isomers of 6 beta,16-dihydroxymethandienone (VIa-c) were discovered. Apparently, reduction of the delta 4 double bond of 16 beta-hydroxymethandienone (V) in the horse yields 16 beta,17 beta-dihydroxy-17 alpha-methyl-5 beta-androst-1-en-3-one (VII). Reduction of the isomers VIa-c results in the corresponding 6 beta,16,17-trihydroxy-17-methyl-5 beta-androst-1-en-3-ones (VIIIa-c). The data presented here suggest that screening for the isomers of VI and VIII, applying the selected-ion monitoring technique, will be the most successful way of proving methandienone administration to a horse.