Alkaloids of South African samples of Calpurnia aurea subsp. Sylvatica

Two new alkaloids, calpurmenine (12β,13α-dihydroxylupanine) and its 13α-pyrrolylcarboxylic acid ester have been isolated from a South African sample of Calpurnia aurea. The alkaloid 10,13-dihydroxylupanine, earlier found in Cadia purpurea but absent from Ethiopian material of Calpurnia aurea, was also identified.     

Sterols with unusual nuclear unsaturation from three cultured marine dinoflagellates

Several new 4α-methyl sterols with unusual unsaturation in the Δ⁸⁽¹⁴⁾-or Δ¹⁴-positions, 4α,24S-dimethyl-5α-cholest-8 (14)-en-3β-ol, 4α-methyl-24ξ-ethyl-5α-cholest-8(14)-en-3β-ol, 4α-methyl-24(Z)-ethylidene-5α-cholest-8(14)- en-3β-ol, 4α,23 (or 22),24ξ-trimethyl-5α-cholesta-8(14),22-dien-3β-ol, 4α,24S(or 23ξ)-dimethyl-5α-cholest-14-en-3β-ol and 14-dehydrodinosterol, have been isolated from extracts of the cultured marine dinoflagellates Amphidinium carterae, A. corpulentum and Glenodinium sp. 4α-Methyl-24ξ-ethyl-5α-cholestan-3β-ol was isolated from the steryl ester fraction of Glenodinium sp. The structures of these new sterols are based upon extensive 360 MHz ¹H NMR and MS analyses.     

A neo-clerodane glucoside and neo-clerodane diterpenoids from Teucrium flavum subsp. Glaucum

From the aerial part of Teucrium flavum subsp. glaucum a new neo-clerodane diterpenoid, teuflavin, and a new 19-nor-neo-clerodane glucoside, teuflavoside, have been isolated, besides the previously known diterpene teuflin. The structures of teuflavin (19-acetoxy-4α,18:15,16-diepoxy-6β-hydroxy-3-keto-neo-cleroda-13(16),14-diene-20,ξ,12S-hemiacetal) and teuflavoside (18-acetoxy-15,16-epoxy-19-nor-neo-cleroda-4,13(16),14-trien-20,12S-olid-6β-yl-2′-O-acetyl-β-d-glucopyranoside) were established by chemical and spectroscopic means and by correlation with known compounds. In addition, the previously known flavone salvigenin has also been obtained from the same source.     

Two new steroidal alkaloids from the mature fruits of Solanum nigrum

Two previously undescribed steroidal alkaloids, compounds 1–2, were isolated from the ripe fruits of Solanum nigrum, along with seven known metabolites (3–9). Based on spectroscopic and chemical evidence, including IR, NMR, and HR-ESI-MS analyses, the structures of the isolated compounds were elucidated as 12β-hydroxy-(3β,22α,25R)-spirosol-5-en-27-acid-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→3)]-β-D-galacopyranoside and 12β-hydroxy-(3β,22α,25R)-spirosol-5-en-27-acid-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-β-D-glucopyranoside. Four steroidal alkaloids (compounds 1–2 and 4–5) were tested for their anti-proliferative effects against the HT-29, A549, and Lewis cell lines. Both of the previously isolated compounds inhibited the proliferation of these three cell lines in a dose-dependent manner, with the most significant effect being in the A549 cells, but neither reached IC₅₀ at 50 μM. These results revealed that S. nigrum had weak cytotoxicity, indicating its clinical safety as a traditional anti-tumor herbal medicine.     

Neo-clerodane diterpenoids from Teucrium pyrenaicum and T. subspinosum

From the aerial parts of teucrium pyrenaicum two new neo-clerodane diterpenoids, teupyrins A and B, have been isolated. The structures of teupyrin A [3β,12S-diacetoxy-4α,18; 15,16-diepoxy-6-keto-neo-cleroda-13(16),14-diene-20R,19-hemiacetal] and teupyrin B [6α-acetoxy-4α,18; 15,16-diepoxy-3β,12ξ,19-trihydroxy-neo-cleroda-13(16),14-diene] were established mainly by spectroscopic means and, in the case of teupyrin A, by X-ray diffraction analysis. The acetone extract of the aerial parts of T. subspinosum yielded four previously known neo-clerodane diterpenoids: teucvin, teuflin, teucrin H2 and 6α-hydroxyteuscordin.     

Triterpenoidal saponins of Pulsatilla koreana roots

Sixteen (1-16) triterpenoidal saponins were isolated from the roots of Pulsatilla koreana, of which four were determined as the previously unknown 23-hydroxy-3β-[(O-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl ester (1), 23-hydroxy-3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl ester (2), 3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl ester (3), and 3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 4)]-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl ester (4), respectively, based on spectroscopic analysis. The inhibition of the lipopolysaccharide-induced nitric oxide production of sixteen isolated compounds was evaluated in RAW 264.7 cells at concentrations ranging from 1 μM to 100 μM.     

A benzopyrroloisoquinoline alkaloid from Ficus fistulosa

A new benzopyrroloisoquinoline alkaloid, fistulosine (1), was isolated from the stem-bark of Ficus fistulosa (Moraceae) collected in Singapore, along with three known phenanthroindolizidine alkaloids, (?)-13aα-antofine (2), (?)-14β-hydroxyantofine (3) and (?)-13aα-secoantofine (4). (?)-13aα-Antofine (2) accounted for the antifungal activity against Aspergillus fumigatus and Candida albicans originally observed in the crude alkaloid extract.     

Polyoxygenated ent-kauranes and water-soluble conjugates in seed of Phaseolus coccineus

C-α and C-β, previously isolated from seed of Phaseolus coccineus, are shown respectively to be the bis-O-isopropylidene and the 16,17-mono-O-isopropylidene derivatives of ent-6α,7α,16β,17-tetrahydroxykauranoic acid. By GC-MS characterization of the products of acidic, basic and enzymatic hydrolysis, water soluble conjugates of the following compounds have been shown to occur in P. coccineus seed: GA₈, GA₁₇, GA₂₀, GA₂₈, ent-6α,7α,13-trihydroxykaurenoic acid, ent-6α,7α,17-trihydroxy-16β-kauranoic acid, ent-6α,7α,16β,17-tetrahydroxykauranoic acid, 7β,13-dihydroxykaurenolide and abscisic acid.     

Alcaloïdes d'Alstonia quaternata

Eleven alkaloids have been isolated from Alstonia quaternata. Three of them, namely 11-methoxy-epi-3α-yohimbine, 10,11-dimethoxy-picrinine designated quaternine, and 19,20-epoxy-N_(a)-methyl, desacetyl, desformo, 2βH-dihydroakuammiline designated quaternoxine, are new alkaloids.     

Diterpenoids from Sideritis varoi subspecies cuatrecasasii: 13C NMR of ent-13-epi-manoyl oxides functionalized at C-12

Several ent-13-epi-manoyl oxides and a new natural product, ent-8α-hydroxylabda-13(16),14-dien-19-oic acid, have been isolated from Sideritis varoi subsp. cuatrecasasii. In addition, a study has been made of some natural and semisynthetic ent-13-epi-manoyl oxides functionalized at C-12.     

Ten cis-clerodane-type diterpene lactones from Gutierrezia texana

Ten new 5α,10α-cis-clerodane-type diterpene lactones were isolated from the aerial parts of Gutierrezia texana. Using NMR techniques and some chemical transformations, the structures were established as 6α,18-dihydroxy-cis-cleroda-3,13(14)-diene-15,16-olide; 18,19-dihydroxy-cis-cleroda-3,13(14)-diene-15,16-olide; cis-cleroda-3,13(14)-diene-15,16:18,19-diolide; 18,19-epoxy-19α-hydroxy-cis-cleroda-3,13(14)-diene-15,16-olide; 3α,4:18,19-diepoxy-18β,19α-dihydroxy-cis-cleroda-13(14)-ene-15,16-olide; 3α,4-epoxy-19α-hydroxy-cis-cleroda-13(14)-ene-15,16:18,19-diolide; 3α,4:18,19-diepoxy-19α-hydroxy-cis-cleroda-13(14)-ene-15,16-olide; 3α,4β,19α-trihydroxy-18,19-epoxy-cis-cleroda- 13(14)-ene-15,16-olide; 19-O-α-L-arabinopyranosyl-cis-cleroda-3,3,13(14)-diene-15,16-olide-19-oic ester and 2β,6α-dihydroxy-cis-cleroda-3,13(14)-diene-15,16:18,6α-diolide. One of the structures was also confirmed by X-ray crystallographic analysis.     

Chemical constituents from Aristolochia tagala and their chemotaxonomic significance

Fifteen compounds were obtained from the extract of the whole herbs of Aristolochia tagala, which were divided into eight aristolactam-type alkaloids (1–6, 14 and 15) and seven aristolochic acid derivatives (7–13). Their structures were identified as aristolactam BII, aristolactam II, sauristolactam, aristolactam I, 7-methoxyaristolactam IV, aristolactam AII, 3-hydroxy-4-methoxy-10-nitrophenanthrene-1-carboxylic acid methyl ester, ariskanin A, ariskanin D, ariskanin E, aristolochic acid C, ariskanin C, ariskanin B, aristolactam-N-β-D-glucoside and cepharanone A N-β-D-glucoside by comparison of their spectral data with those reported previously in the literature. The chemotaxonomic relationships between A. tagala and other species of genus Aristolochia were also discussed. As a result, the isolated compounds closely matched the ones obtained in other species of the genus.     

Isolation and identification of novel sulfur-containing metabolites of spironolactone (Aldactone®)

In the urine of subjects given an oral dose of spironolactone [3-(3-oxo-7α-acetylthio-17β-hydroxy-4-androsten-17α-y1)propionic acid γ-lactone], six metabolites have been detected. One of the major metabolites was found to be the previously characterized de-thioacetylated compound, 3-(3-oxo-17β-hydroxy-4,6-androstadien-17α-y1)propionic acid γ-lactone (canrenone). Besides this a new major sulfur-containing metabolite has been isolated and identified as 3-(3-oxo-7α-methylsulfinyl-6β,17β-dihydroxy-4-androsten-17α-y1)propionic acid γ-lactone. This structural assignment was based on detailed analysis of its IR, NMR and UV spectra as well as comparison of its physical constants and chromatographic (TLC and GLC) characteristics with a synthetic sample. The three minor metabolites were found to be very labile and were readily converted to canrenone.     

Quinovic acid glycosides from Guettarda angelica

Two new triterpene glycosides isolated from the root bark Guettarda angelica were proven to be quinovic acid-3β-O-[β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside] and quinovic acid-3β-O-β-d-glucopyranosyl-(28 → 1)-β-d-glucopyranosyl ester. In addition quinovic acid and two known glycoside derivatives (quinovic acid-3β-O-β-d-glucopyranoside and quinovic acid-3β-O-α-l-rhamnopyranoside) were isolated. The structures were elucidated by spectroscopic analysis of the peracetyl methyl ester derivatives.     

A triterpene and saponin from roots of Ilex pubescens

A new triterpene and its glycoside have been isolated from methanol extract of roots of Ilex pubescens. Their structures were established as 3β, 19α-dihydroxyurs-12-en-24,28-dioic acid and its 28-β-d-glucopyranosyl ester, based on chemical and spectral evidence.     

Diterpenoids from Nepeta tuberosa subsp. reticulata

Three new diterpene compounds have been isolated from Nepeta tuberosa subsp. reticulata and their structures elucidated by spectroscopic methods. They were identified as diisopimaryl malonate isopimarylmalonic acid and 7-oxo-isopimara-8,15-dien-18-ol. We have also isolated 4aα,7α,7aβ-nepetalactone, 4aα,7α,7aα-nepetalactone, 3α-hydroxy-4α,4aα,7α 4α,4aα,7α,7aα-dihydronepetalactone, isopimaryl acetate, isopimarol, isopimaric acid, 8(14),15-isopimaradien-7α,18-diol, myrceocomunic acid and α-tocopheryl quinone.     

Unusual oleanane-type saponins from Arenaria montana

Three oleanane-type saponins, 3-O-β-d-glucopyranosylechinocystic acid 28-O-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (1), 3-O-β-d-glucopyranosylechinocystic acid 28-O-α-l-arabinopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (2), 3-O-β-d-glucopyranosylcaulophyllogenin 28-O-β-d-apiofuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[β-d-apiofuranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-α-l-rhamnopyranosyl ester (3) were isolated from the whole plant of Arenaria montana. Their unusual structures for the Caryophyllaceae family were established mainly by 2D NMR techniques and mass spectrometry.     

Synthesis and stereochemistry of C-3- and C-7-linked (O-carboxymethyl)-oximino- and hemisuccinamido derivatives of 5 alpha-dihydrotestosterone.

The 3-(O-carboxymethyl)oximino derivative of 17β-hydroxy-5α-androstan-3-one (5α-dihydrotestosterone) was prepared. Thin-layer chromatography of the corresponding methyl ester showed the presence of two syn (60%) and anti (40%) geometrical isomers of the oxime chain to the C-4 position, which were characterized by ¹³C nmr. The 3β-hemisuccinami-do-5α-androstan-17β-ol was obtained after selective saponification with potassium carbonate of the 17β-hemisuccinate group of the 3,17-dihemi-succinoylated derivative of the previously described 3β-amino-5α-androstan-17β-ol. This 3β-hemisuccinamide was purified as the corresponding methyl ester-17β-acetate and was regenerated after saponification. The 3,3'-ethylenedioxy-7-oxo-5α-androstan-17β-yl acetate was obtained in quantitative yield by catalytic hydrogenation over 10% palladium-oncharcoal of the Δ⁵-7-oxo precursor in a dioxane-ethanol mixture containing traces of pyridine. The exclusive 5α-configuration of this hydrogenated product was established from nmr data and was confirmed by the synthesis of methyl 3,3'-ethylenedioxy-7-oxo-5β-cholan-24-oate as 5β-H-reference compound. The preceding 5α-H-7-ketone was converted into the 7-(O-carboxymethyl)oximino derivative (syn isomer to the C-6 position, exclusively) which was esterified into the corresponding methyl ester. The selective hydrolysis of the 3-ethyleneketal group was achieved by a short treatment with a formic acid-ether 1:1 (v/v) mixture at 20°C. Saponification of the latter reaction product with ethanolic potassium hydroxide gave the 7-(O-carboxymethyl)oximino-17β-hydroxy-5α-androstan-3-one derivative, which was characterized as the corresponding methyl ester. The reduction of the oxime of the 5α-H-7-ketone with sodium in ethanol or with lithium-aluminium hydride gave respectively the 7β-amine or the 7α-amine as the major product. The 7β- and 7α-configurations were established from nmr spectra of the corresponding 7-acetamido derivatives. The 7β- and 7α-hemisuccinamido derivatives were prepared from the mixture of 7β- and 7α-amines, as described above for 3-derivatives and were isolated after thin-layer chromatography of the methyl esters, followed by saponification of the corresponding 17β-acetates.     

2-Deoxychamaedroxide,a neo-clerodane diterpenoid from Teucrium divaricatum

A new neo-clerodane diterpenoid, 2-deoxychamaedroxide, has been isolated from the aerial parts of Teucrium divaricatum subsp. canescens. Also identified were the previously known diterpenoids teuflin, teucrin H₂, teuflidin, teucrins A, F and G, 6β-hydroxy-teuscordin, montanin D and dihydroteugin. The structure of 2-deoxychamaedroxide, (12S)-4β,6β; 15,16-diepoxy-neo-clerodane-13(16),14-diene-18,19; 20,12-diolide, was established mainly by spectroscopic means.     

Minor triterpenoids of Fomes officinalis

The degraded triterpenoid, 3β,6β-dihydroxy-4,4,14α-trimethyl-Δ⁸-5α-pregnene-20-one (II) and 3-keto-dehydrosulfurenic acid (III), have been isolated from the extracts of Fomes officinalis and their structures determined.