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At least 19 recordsLinked to original sources
PubMed1977

[Formation of a depside-caffeine complex during cold conservation of coffee leaf samples in a hydro-ethanolic medium. Methodologic implications for the extraction of depsides].

The depsides present in coffee leaves are not apparent upon extraction with ethanol if the plant material has been fixed in boiling ethanol then maintained at - 25 degrees C. A complex formed with cafein prevents the extraction and this artefact from cold conservation concerns chlorogenic acid and its isomers. A treatment with chloroform can break the complex and allows the depsides to be dosed. The complex does not seem to exist in living tissues.

Anhydrides↗
PubMed1999

A General Methodology for Automated Solid-Phase Synthesis of Depsides and Depsipeptides. Preparation of a Valinomycin Analogue.

A general methodology is described that allows the solid-phase synthesis of depsides and depsipeptides from chiral alpha-hydroxy- and alpha-amino acids. The results of studies with different protecting groups for the alpha-hydroxy acids and coupling systems for depside bond formation are presented. The oligomers were prepared using a Wang-type linker with final TFA/CH(2)Cl(2) cleavage. Depside linkage of the THP-protected acids (THP = tetrahydropyranyl) to the resin-bound chains was achieved with DIC/DMAP (DIC = diisopropylcarbodiimide, DMAP = 4-(dimethylamino)pyridine) and monitored by a color test with 4-(p-nitrobenzyl)pyridine. THP deprotection was achieved with p-TsOH in CH(2)Cl(2)/MeOH and was monitored by GC. Following the established procedure, depsides made up from the same enantiomer (i.e., H-[L-Man](8)-OH, 25), by both enantiomers (i.e., H-[D-Man-L-Man](4)-OH, 26), or by different hydroxy acids in the same chain (i.e., H-[L-Lac-L-Hiv](3)-OH, 27) were prepared with an average yield of 95-97% per cycle. The linear precursor of the valinomycin analogue 30 ([L-Val-D-Man-D-Val-L-Lac](3)) was entirely synthesized on resin and cyclized in solution. Cyclization of the open-chain depsides is the final step in the preparation of a new class of chiral alpha-hydroxyester macrocycles.

Journal Article↗
PubMed1982

Depside as potent inhibitor of prostaglandin biosynthesis: a new active site model for fatty acid cyclooxygenase.

Forty depsides and depsidones, the esters of phenolcarboxylic acids, were examined for their inhibitory effect against prostaglandin biosynthesis with rabbit renal microsomes. 4-0-Methylcryptochlorophaeic acid was the most active inhibitor so far tested and its IC50 value was 0.34 muM. Kinetic investigation has shown that this depside acts competitively with respect to arachidonic acid as most of the non - steroidal antiinflammatory drugs. X-Ray analysis has revealed that 4-0-methylcryptochlorophaeic acid maintains its rigid conformation by forming a strong hydrogen bond between the hydroxyl and methoxyl groups. Comparison of CPK models between 4-0-methylcryptochlorophaeic acid and non-steroidal antiinflammatory drugs revealed that the carboxyl group and the two rings of these drugs are almost superimposable to those of the depside. This finding led us to propose a new active site model based on the three dimentional structure of the depside.

Animals↗
PubMed2003

Mechanisms of transformation of the antioxidant kaempferol into depsides. Gamma-radiolysis study in methanol and ethanol.

In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol.

Antioxidants↗
PubMed1993

[Separation and quantitative determination of seven aqueous depsides in Salvia miltiorrhiza by HPTLC scanning].

A new analytical method for the separation and determination of seven aqueous depsides in salvia miltiorrhiza by HPTLC has been developed. The seven depsides are protocatechualdehyde, caffeic acid, methyl rosmarinate, rosmarinic acid, salvianolic acid A, B and C. Using chloroform-ethyl acetate-benzene-formic acid(2.4:2:1:0.6) as developing solvent A, protocatechualdehyde was separated; using chloroform-ethyl acetate-benzene-formic acid-methanol (1.5:2:1:1:0.1) as developing solvent B, the other six constituents were well separated. The aqueous depsides were detected at the wave lengths of lambda S = 300 nm and lambda R = 240. This method is simple, rapid, sensitive and accurate. The contents of seven depsides in several Salvia species were determined.

Benzaldehydes↗
PubMed2002

Radiolysis of quercetin in methanol solution: observation of depside formation.

Radiolysis of the flavonol quercetin, a natural antioxidant, was performed in methanol. The degradation process was followed by HPLC analyses. The major product was identified as a depside (Q1) by NMR and LC-MS. The G(Q1) radiolytic factor was plotted versus the initial concentration of quercetin. This radiolytic process was attributed to the CH3O* radicals presented in the irradiated medium. The proposed mechanism invoked a stereospecific oxidation of the 3-hydroxyl group of quercetin which led to C-ring opening and to the formation of the depside Q1. In presence of water, Q1 was transformed into another depside, Q2, by an inverse esterification reaction. A chemical equilibrium was observed between Q1 and Q2. The comprehension of the radiolytic process of quercetin in methanol solution is of importance. Indeed, the same type of oxidative reactions could occur on flavonoids during preservation of food by ionizing radiation.

Chromatography, High Pressure Liquid↗
PubMed2000

[Effects of phytohormones on growth and content of depsides in Salvia miltiorrhiza suspension cells].

This paper deals with the effects of 2,4-D, BA and GA3 on the growth and content of two depsides (rosmarinic acid and lithospermic acid B) in suspension cells of Salvia miltiorrhiza. The results showed cell growth and rosmarinic acid content reached the maximum on the 12th day and lithospermic acid B content on the 16th day after incubating cells in the subculture medium MS + 2, 4-D 1 mg/L + KT 0.1 mg/L. This cell line was a growth-product-associated. With the same concentration (1 mg/L), 2, 4-D stimulated the cell growth but prohibited the formation of lithospermic acid B; GA3 inhabited the cell growth but stimulated the formation of two depsides; The effects of BA is between 2, 4-D and GA3. The concentration optimum of phytohormones tested displayed 3 mg/L for BA and 1 mg/L for GA3. For the optimum time of adding BA and GA3 was in med-term (the 8th day) and early term (at the beginning) of culture period respectively. The synergiatic function of BA and GA3 on the depside formation was also showed that adding GA3 (1 mg/L) was favour for the formation of lithospermic acid B of the suspension cell cultured in the medium containing BA 3 mg/L. The suitable time of adding GA3 was the 6the day after incubating cells in the medium of MS + BA 3 mg/L.

Benzofurans↗
PubMed1994

Antioxidant activity of depsides and depsidones.

The antioxidant activity of lichenic metabolites, depsides and depsidones, was assessed by their effects as inhibitors of rat brain homogenate auto-oxidation and beta-carotene oxidation. The results obtained in both systems indicate that lichenic metabolites afford a moderate protection in the microM concentration range. The largest effect was measured employing 1'-chloropannarin in the brain homogenate auto-oxidation, where a 66% protection was afforded at 1.7 microM. This protection is very similar to that elicited by addition of the reference antioxidant propylgallate (70% protection at 1.3 microM).

Animals↗
PubMed2000

Depsides as non-redox inhibitors of leukotriene B(4) biosynthesis and HaCaT cell growth, 2. Novel analogues of obtusatic acid.

Aseries of obtusatic acid analogues has been synthesized and evaluated as inhibitors of leukotriene B(4) (LTB(4)) biosynthesis and as antiproliferative agents. The 4-O-benzylated and the 4-O-demethylated congeners were the most potent inhibitors of LTB(4) production of the depside class of compounds, with IC(50) values in the submicromolar range. Furthermore, these compounds do not function as redox-based inhibitors because they were not reactive against a stable free radical, 2,2-diphenyl-1-picrylhydrazyl, and did not produce appreciable amounts of deoxyribose degradation as a measure of their potency to generate hydroxyl radicals. Some obtusatic acid congeners were also potent inhibitors of keratinocyte growth. Growth inhibition was not mediated by damage to the cell membrane, as the activity of lactate dehydrogenase released from the cytoplasm was in the control range.

Animals↗
PubMed1990

Effect of salvianolic acid A, a depside from roots of Salvia miltiorrhiza, on gastric H+,K(+)-ATPase.

Salvianolic acid A, a depside from the roots of Salvia miltiorrhiza, inhibited pig gastric H+,K(+)-ATPase and pNPPase with 50% inhibition values (IC50) of 5.2 x 10(-7) M and 1.7 x 10(-6) M, respectively. Kinetic studies revealed that the inhibition patterns induced by salvianolic acid A were competitive with respect to ATP and noncompetitive with respect to K+. Salvianolic acid A (25 mg/kg, i.p.) significantly inhibited acid secretion in pylorus-ligated rats. At the same dose it also showed a significant reduction in the formation of gastric lesion induced by water immersion and restraint stress. These results suggest that salvianolic acid A shows antisecretory and antiulcer activity by inhibiting the gastric H+,K(+)-ATPase.

Adenosine Triphosphatases↗
PubMed1997

Depsides and depsidones as inhibitors of HIV-1 integrase: discovery of novel inhibitors through 3D database searching.

Seventeen lichen acids comprising despides, depsidones, and their synthetic derivatives have been examined for their inhibitory activity against HIV-1 integrase, and two pharmacophores associated with inhibition of this enzyme have been identified. A search of the NCI 3D database of approximately 200,000 structures yielded some 800 compounds which contain one or the other pharmacophore. Forty-two of these compounds were assayed for HIV-1 integrase inhibition, and of these, 27 had inhibitory IC50 values of less than 100 microM; 15 were below 50 microM. Several of these compounds were also examined for their activity against HIV-2 integrase and mammalian topoisomerase I.

Anti-HIV Agents↗
PubMed2002

Agonodepsides a and B: two new depsides from a filamentous fungus F7524.

Two new compounds, agonodepsides A (1) and B (2), were isolated from a nonsporulating filamentous fungus, F7524. The compounds were purified via reversed-phase chromatography and their structures determined by spectroscopic methods. Agonodepside A (1) was found to inhibit the mycobacterial InhA enzyme with an IC50 value of 75 microM, while 2 was inactive at 100 microM.

Bacterial Proteins↗
PubMedDate not supplied

Phenolic acids and depsides from some species of the Erodium genera.

Six natural polyphenolic compounds, brevifolin carboxylic acid, brevifolin, ellagic acid, methyl gallate, gallic acid and protocatechuic acid have been isolated from the methanol extract of the whole plant of Erodium cicutarium (L.) L.'Hérit. (Geraniaceae). Structures were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of these compounds in the other species of the Erodium genera (E. botrys, E. chium, E. ciconium, E. cicutarium, E. glutinosum subsp. dunense, E. gruinum, E. manescavi, E. pelargoniiflorum, E. petraeum) were examined by HPLC with a RP-18 column, and MGD-TLC methods on unmodified silica gel and silica gel chemically modified with polar and nonpolar groups (HPTLC-Si 60 LiChrospher, HPTLC-NH2, HPTLC-DIOL, HPTLC RP-18W).

Chromatography, High Pressure Liquid↗