Tigliane Diterpenoids as a New Type of Antiadipogenic Agents Inhibit GRα-Dexras1 Axis in Adipocytes.

The phytochemical study of Euphorbia prolifera led to the isolation of two tiglianes (1 and 2) and 23 mysrinanes (3-25). Most of these isolates showed significant antiadipogenic activity in 3T3-L1 adipocyte without apparent cytotoxicity. Subsequent structural modification yielded 10 derivatives, among which 1a, the 5- O-acetyl derivative of 1, turned out to be the most active compound with improved triglyceride-lowering activity (EC50 for 1 and 1a: 0.61 and 0.32 µM, respectively) and reduced cytotoxicity (selectivity index for 1 and 1a: 28 and 312, respectively). The structure-activity relationship study revealed that the trans-fused 5/7/6 ring system in an angular shape was important to the activity. A mechanistic study indicated that 1 and 1a could inhibit the glucocorticoid receptor α-Dexras1 axis in adipocyte, leading to the retardation of cell differentiation at the early stage. These findings may provide a new type of lipid-lowering agents for future antiobesity drug development.

Phorbol Rearrangements.

An alternative procedure for isolation of 4ß-phorbol from seeds of Croton tiglium has been developed, and an artifact containing a furan ring formed by rearrangement of 12,13,20- O-triacylated phorbol derivatives into (6b S,7 R,8 R,8a S)-2-(hydroxymethyl)-5,7,9,9-tetramethyl-3,7,8,9,9a,9b-hexahydrocyclopropa[3',4']benzo[1',2':3,4]cyclohepta[1,2- b]furan-6b,8,8a-triol (8a) has been characterized. A mechanism involving an oxidative rearrangement and a decarboxylation for formation of the artifact is proposed.

Regulation of cytochrome P450 mRNA expression in primary porcine hepatocytes by selected secondary plant metabolites from chicory (Cichorium intybus L.).

Chicory (Cichorium intybus) has been shown to induce enzymes of pharmacokinetic relevance (cytochrome P450; CYP). The aim of this study was to investigate the effects of selected secondary plant metabolites with a global extract of chicory root, on the expression of hepatic CYP mRNA (1A2, 2A19, 2C33, 2D25, 2E1 and 3A29), using primary porcine hepatocytes. Of the tested secondary plant metabolites, artemisinin, scoparone, lactucin and esculetin all induced increased expression of specific CYPs, while esculin showed no effect. In contrast, a global extract of chicory root decreased the expression of CYP1A2, 2C33, 2D25 and 3A29 at high concentrations. The results suggest that purified secondary metabolites from chicory affect CYP expression and thereby might affect detoxification in general, and that global extracts of plants can have effects different from individual components.

Alienusolin, a new 4α-deoxyphorbol ester derivative, and crotonimide C, a new glutarimide alkaloid from the Kenyan Croton alienus.

Two novel compounds, alienusolin, a 4α-deoxyphorbol ester (1), crotonimide C, a glutarimide alkaloid derivative (2), and ten known compounds, julocrotine (3), crotepoxide (4), monodeacetyl crotepoxide (5), dideacetylcrotepoxide, (6), ß-senepoxide (7), α-senepoxide (8), (+)-(2S,3R-diacetoxy-1-benzoyloxymethylenecyclohex-4,6-diene (9), benzyl benzoate (10), acetyl aleuritolic (11), and 24-ethylcholesta-4,22-dien-3-one (12) were isolated from the Kenyan Croton alienus. The structures of the compounds were determined using NMR, GCMS, and HRESIMS studies.

Two new tigliane diterpene esters from the flower buds of Daphne genkwa.

The phytochemical investigation of the flower buds of Daphne genkwa yielded four highly oxygenated tigliane diterpene esters (1-4), including two new phorbol derivatives, 12-O-(2'E,4'E-decadienoyl)-7-oxo-5-ene-phorbol-13-acetate (1) and 12-O-neodecanoyl-7-oxo-5-ene-phorbol-13-acetate (2). The molecular structures of the isolated compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR.

Schistosomiasis suppressing deoxyphorbol esters from Euphorbia cauducifolia L. latex.

The molluscicidal activity of E. Cauducifolia L. latex, extracted in various organic solvents, was tested against Biomphalaria glabrata snails, using Bayluscide as a control. The ethyl acetate extract was found to be the most active and in bioassay guided HPLC fractionation yielded eight ( 1- 8) compounds. The structure and relative configuration of the isolates were established through spectroscopic (UV, IR, (1)H, (13)C NMR, 2D NMR, HSQC, HMQC, HMBC, COSY-45 degrees , TOCSY, HOHAHA, HOESY, ROESY, NOESY, SECSY, and NOE) techniques and mass measurements. These were named as: 13-acetoxy-20- O-angeloyl-12-deoxyphorbol ( 1), 13- O-[N-(2-aminobenzoyl)]anthraniloyl-20-acetoxy-12-deoxyphorbol ( 2), 13,20- O-dibezoyl-12-deoxyphorbol ( 3), 13,20- O-diangeloyl-12-deoxyphorbol ( 4), 13- O-angeloyl-20- O-[N-(2-aminobenzoyl)]anthraniloyl-12-deoxyphorbol ( 5), 13- O-tigloyl-20- O-[N-(2-aminobenzoyl)]anthraniloyl-12-deoxyphorbol ( 6), 13- O-benzoyl-20- O-[N-(2-aminobenzoyl)]anthraniloyl-12-deoxyphorbol ( 7), and 13- O-hexanoyl-20- O-[N-(2-aminobenzoyl)]anthraniloyl-12-deoxyphorbol ( 8). The literature reveals that all of the isolates were new natural metabolites and active against mollusks. Compounds 1 and 2, which were esterified at C-13 with acetoxy or N-(2-aminobenzoyl) anthraniloyloxy, showed twice the activity of the control while others ( 3- 8) were equipotent.

Isolation and structure of pedilstatin from a republic of maldives Pedilanthus sp.

A new cancer cell growth inhibitor designated pedilstatin (1) was isolated from a Republic of Maldives Pedilanthus sp. The structure was determined to be 13-O-acetyl-12-O-[2'Z,4'E-octadienoyl]-4alpha-deoxyphorbol on the basis of high-resolution mass spectral and 2D NMR assignments. Pedilstatin was found to significantly inhibit growth of the P388 lymphocytic leukemia cell line with an ED(50) of 0.28 microg/mL, to afford, at concentrations of 2-5 microM, protection (to 80%) of human-derived lymphoblastoid CEM-SS cells from infection and cell-killing by HIV-1, and to show inhibition of protein kinase C with a K(i) of 620 +/- 20 nM.

A rapid method for isolating phorbol from croton oil.

The published method for isolating phorbol from croton oil has been improved and made more rapid, mainly by the addition of silica-gel column chromatography. The spectral characteristics are recorded, including the 13C nuclear magnetic resonance (NMR) spectrum.

Cocarcinogens of the diterpene ester type from Croton flavens L. and esophageal cancer in Curaçao.

From the roots of Croton flavens L., 3 highly irritant and tumor promoting Croton factors F1--F3 and the corresponding 3 cryptic Croton factors F'1--F'3 were isolated and characterized as novel esters of 16-hydroxy- and 4-deoxy-16-hydroxyphorbol, respectively. These findings suggest that tumor promoters of the phorbol ester type, ingested through the widespread and frequent use of Croton flavens according to local habits, may be causally related to the well recognized high rate of esophageal cancer on Curaçao.

Qualitative and quantitative separation of a series of phorbol-ester tumor promoters by high-pressure liquid chromatography.

A high-pressure liquid chromatographic (HPLC) method using a micro-particulate silica column and gradient elution was developed that separated 12-O-tetradecanoylphorbol-13-acetate (TPA) from 20-oxo-TPA; 12-O-tetradecanoylphorbol (TP); 13-O-acetylphorbol (PA), and from the diterpene alcohol, phorbol (P). A series of other phorbol-ester tumor promoters were also separated via HPLC. Spectrophotometric determination at 232 nm allowed detection sensitivities of 0.05 microgram of TPA. When tritiated TPA was applied to mouse skin, the majority of the tritiated product recovered was TPA, indicating only minimal metabolism of TPA and no need for metabolic activation for tumor promotion.

New highly irritant euphorbia factors from latex of Euphorbia tirucalli L.

From the latex of Euphorbia tirucalli L. growing in Madagascar, 5 new euphorbia factors were isolated. They were characterized as 13-O-acetyl-12-O-acylphorbol- and 12-O-acetyl-13-O-acylphorbol derivatives carrying homologous conjugated unsaturated fatty acids as acyl groups. Furthermore, 2 mixtures of homologous 3-O-acylingenol derivatives are obtained carrying the same type of unsaturated fatty acids. Due to their highly unsaturated acyl groups all Euphorbia factors or factor groups isolated are highly sensitive to autoxidation.

The succulent Euphorbias of Nigeria. II. aliphatic diterpene esters of the latices of E. poisonii Pax. and E. unispina N.E. Br.

Methanol-preserved latices of E. poisonii and E. unispina were examined for irritant principles. Six esters of the parent diterpene 12-deoxyphorbol were identified by spectroscopic and chemical methods. Three were the aliphatic esters 12-deoxyphorbol-13-(2-methyl-butyrate), 12-deoxyphorbol-13-angelate and 12-deoxyphorbol-13-isobutyrate, and a further three compounds were the 20-acetyl equivalents. Isobutyrate esters were absent from the latex of E. unispina, an observation of possible value in the identification of these two similar species.

Skin irritants of Euphorbia fortissima.

By means of a combination of partition and chromatographic methods six irritant constituents were isolated from the fresh latex of Euphorbia fortissima. Compounds A-D were di-esters of the common parent diterpene 12-deoxyphorbol, and compounds E and F were mono-esters of the same diterpene. The fresh latex had an irritant dose 50% (ID50) on mice of 0-64 mug mul- minus 1. Compounds A-D are short-acting irritants reaching a maximum activity within 4 h of application to the skin, whilst the monoesters maintained potent irritant effects for up to 24 h. Selective hydrolysis of the di-esters at the C-20 primary ester group also produced mono-esters of greater potency after 24 h. An increase in the length of the fatty acid located at C-13 produced greater biological activity in both the mono- and di-ester groups.