Effects of the antimycobacterial compound 2-phenoxy-1-phenylethanone on rat hepatocytes and formation of metabolites

Context: Neolignans are usually dimers formed by oxidative coupling of allyl and propenyl phenols, and the neolignan analogue, 2-phenoxy-1-phenylethanone (LS-2) is a promising antimycobacterial compound showing very weak cytotoxicity in mammalian cells and lack of acute toxicity in murine models. Objectives: To investigate the mechanism of action of LS-2 in rat hepatocytes by evaluating the activity levels of enzymes related to oxidation status and drug-metabolizing activity. Materials and methods: Hepatocytes were treated with LS-2 from 0.05 up to 1 mM, for 24 and 48 h, and reduced glutathione (GSH), lipid peroxidation and cytochrome P450 enzyme (CYP450) activity were assayed. A homologous series of phenoxazone ethers were used as substrates to measure the enzymatic profile. The biotransformation of LS-2 was studied in hepatocytes by gas chromatography-mass spectrometry (GC-MS) for detection and analysis of possible metabolites. Results: Hepatocytes treated with LS-2 up to 1 mM for 24 or 48 h did not induce the formation of GSH and lipid peroxidation. O-Dealkylation activities of the isoenzymes CYP4501A1, CYP4501A2, CYP4502B1 and CYP4502B2 were also not detected in the hepatocytes treated with LS-2 for 24 or 48 h. Discussion and conclusion: The results indicate that LS-2 or its two detected metabolites, 2-phenoxy-1-phenylethanol and 2,4-(2-hydroxy-2-phenylethoxy) phenol, are not cytotoxic to rat hepatocytes. These compounds maintain a balance between the production of pro-oxidant agents and their respective antioxidant systems. The data show that enzymes related to oxidation status and drug-metabolizing activities are not involved in the mechanism of action of LS-2.

Secondary metabolites from Spirotropis longifolia (DC) Baill and their antifungal activity against human pathogenic fungi

A phytochemical study of the ethyl acetate extract of the roots and adventitious roots of Spirotropis longifolia, a monodominant tree species of the Guianan rainforest, has allowed the isolation of three compounds: 2- hydroxy-8,9-methylenedioxy-2',2'-dimethylpyrano-[5',6':4,3]-6a-prenyl-[6aS,11aS]-pterocarpan (spirotropin A), 2-hydroxy-8,9-methylenedioxy-2',2'-dimethy1-3',4'-dihydropyrano-[5',6':4,3]-6a-prenyl-(6aS,11aS]-pterocarpan (spirotropin B), and 5,7-dihydroxy-6.8-dipreny1-2 ''''.2 ''''-dimethylpyrano[5 '''',6 '''': 3',4]-isoflavone (spirotropone). In addition, 10 known compounds, trans-oxyresveratrol, trans-resveratrol, piceatannol, daidzein, genistein, isoprunetin, lupeol, latifolol, gnetin D and gnetin E, were also isolated. These compounds were evaluated for their antifungal activity and their cytotoxicity, and their structures were established by 1D and 2D NMR, HRMS, CD and optical rotation measurements. (C) 2011 Elsevier Ltd. All rights reserved.

Aminoacylase 1-catalysed deacetylation of bioactives epoxides mycotoxin-derived mercapturates; 3,4-epoxyprecocenes as models of cytotoxic epoxides

The mycotoxin aflatoxin B1 (AFB1) is a carcinogenic food contaminant which is metabolically activated by epoxydation. The metabolism of mycotoxins via the mercapturate metabolic pathway was shown, in general, to lead to their detoxication. Mercapturic acids thus formed (S-substitued-N-acetyl-L-cysteines) may be accumulated in the kidney and either excreted in the urine or desacetylated by Acylase 1 (ACY1) to yield cysteine S-conjugates. To be toxic, the N-acetyl-L-cysteine-S-conjugates first have to undergo deacetylation by ACY 1. The specificity and rate of mercapturic acid deacetylation may determine the toxicity, however the exact deacetylation processes involved are not well known. The aim of this study was to investigate the role of ACY1 in the toxicity of some bioactive epoxides from Aflatoxin B1. We characterized the kinetic parameters of porcine kidney and human recombinant aminoacylase-1 towards some aromatic and aliphatic-derived mercapturates analogue of mycotoxin mercapturic acids and 3,4-epoxyprecocene, a bioactive epoxide derivated from aflatoxin. The deacetylation of mercapturated substrates was followed both by reverse phase HPLC and by TNBS method. Catalytic activity was discussed in a structure function relationship. Ours results indicate for the first time that aminoacylase-1 could play an important role in deacetylating mercapturate metabolites of aflatoxin analogues and this process may be in relation with their cyto- and nephrotoxicity in human. (C) 2012 Published by Elsevier Masson SAS.

Evaluating methods for the isolation of marine-derived fungal strains and production of bioactive secondary metabolites

In the present investigation we evaluate methods for the isolation and growth of marine-derived fungal strains in artificial media for the production of secondary metabolites. Inoculation of marine macroorganisms fragments in Petri dishes proved to be the most convenient procedure for the isolation of the largest number of strains. Among the growth media used, 3% malt extract showed the best result for strains isolation and growth, and yielded the largest number of strains from marine macroorganisms. The percentage of strains isolated using each of the growth media which yielded cytotoxic and/or antibiotic extracts was in the range of 23-35%, regardless of the growth media used. Further investigation of extracts obtained from different marine-derived fungal strains yielded several bioactive secondary metabolites, among which (E)-4-methoxy-5-(3-methoxybut-1-enyl)-6-methyl-2H-pyran-2-one is a new metabolite isolated from the Penicillium paxilli strain Ma(G)K.

Sex differences in the excretion of fecal glucocorticoid metabolites in the Syrian hamster

We verified the relevance of measuring fecal glucocorticoid metabolites (FGM) to assess the stress response of the Syrian hamster. Male and female hamsters (n = 10 each) were submitted to an adrenocorticotropic hormone (ACTH) challenge test, whereas animals in the control group received 0.5 mL of sterile isotonic saline solution. All feces voided by each animal were collected at 4 h intervals from 24 h before (baseline) until 48 h after injections. FGM were quantified using an 11-oxoetiocholanolone enzyme immunoassay (EIA). Basal concentrations of FGM were almost four times higher in males than in females. Following ACTH administration, FGM levels started rising from 8 h onwards, reaching peak concentrations 20 or 28 h post injection in males and females, respectively. Despite the much higher absolute concentrations present in males, the relative increase (500%) in response to the ACTH stimulation was similar in both sexes. Sex differences in FGM levels are in accordance with results reported by others regarding the hamster adrenal physiology. The comparison of the adrenocortical response of males and females to an ACTH challenge provided new information about the amplitude and the timing of such a response and the excretion of glucocorticoids in both sexes. We demonstrated for the first time in the Syrian hamster that adrenocortical activity can be monitored in fecal samples in a noninvasive way. Our study provides a humane, practical, and noninvasive alternative to blood removal and therefore a powerful tool for stress-related studies in a species frequently used as an animal model in medical research.

Secondary Metabolites from the Phloem of Piper solmsianum (Piperaceae) in the Honeydew of Edessa meditabunda

Introduction The phytochemistry of species of the genus Piper has been studied extensively, including Piper solmsianum. However, no studies have addressed the phytochemistry of the sap content of Piper species. Objective To evaluate the transferring of secondary compounds from the saps of P. solmsianum to the honeydew of Edessa meditabunda. Methodology The honeydew of E. meditabunda and saps of P. solmsianum were analysed by GC-MS, H-1-NMR and LC-MS. Results The lignan (-)-grandisin and the phenylpropanoid (E)-isoelemicin were detected in both saps of P. solmsianum and honeydew of E. meditabunda. Conclusion Analysis of honeydew secreted by the sap-sucking insect E. meditabunda indicated that (-)-grandisin and (E)-isoelemicin are absorbed from the phloem of Piper solmsianum. Copyright (c) 2012 John Wiley & Sons, Ltd.

Antioxidant, anti-acetylcholinesterase and cytotoxic activities of ethanol extracts of peel, pulp and seeds of exotic Brazilian fruits Antioxidant, anti-acetylcholinesterase and cytotoxic activities in fruits

Ethanol extracts of powdered genipap (Genipa americana L), umbu (Spondia tuberosa A.) and siriguela (Spondia purpurea L) prepared from separate pulp, seeds and peel were investigated for their (i) antioxidant capacity, which was evaluated by various known methods; (ii) acetylcholinesterase (AChE) inhibitory activity; and (iii) cytotoxic effect on corneal epithelial cells of sheep. The highest values of total phenolic content were obtained with peel and seed extracts. Siriguela and umbu (seeds and peel) extracts displayed the highest antioxidant activities. Lipid peroxidation assays using mimetic biomembranes and mouse liver homogenates indicated that genipap pulp is a promising antioxidant. The investigation of phenols and organic acid contents revealed the presence of quercetin, citric and quinic acids, chlorogenic acid derivatives, among others, in several extracts, with the highest amount found in siriguela seeds. Genipap pulp and siriguela seed ethanol extracts presented an AChE inhibition zone similar to that of the positive control, carbachol. AChE inhibition assay with chlorogenic acid, one of the main constituents of siriguela seeds, revealed that this acid showed activity similar to that of the control physostigmine. These data suggest that these extracts are potentially important antioxidant supplements for the everyday human diet, pharmaceutical and cosmetic industries. (C) 2012 Elsevier Ltd. All rights reserved.

Dillapiole as Antileishmanial Agent: Discovery, Cytotoxic Activity and Preliminary SAR Studies of Dillapiole Analogues

In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structureactivity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC50?=?69.3 mu M) and Leishmania brasiliensis (IC50?=?59.4 mu M) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC50?=?99.9 mu M for L. amazonensis and IC50?=?90.5 mu M for L. braziliensis) and 3 (IC50?=?122.9 mu M for L. amazonensis and IC50?=?109.8 mu M for L. brasiliensis) were less active than dillapiole (1). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues.

SEASONAL VARIATION OF THE MAJOR SECONDARY METABOLITES PRESENT IN THE EXTRACT OF Eremanthus mattogrossensis Less (Asteraceae: Vernonieae) LEAVES

The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado. Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H2O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.

SECONDARY METABOLITES FROM NUDIBRANCHS Tambja stegosauriformis, Hypselodoris lajenis AND Okenia zoobotryon AND FROM BRYOZOANS Zoobotryon verticillatum AND Bugula dentata FROM THE BRAZILIAN COASTLINE

SECONDARY METABOLITES FROM NUDIBRANCHS Tambja stegosauriformis, Hypselodoris lajenis AND Okenia zoobotryon AND FROM BRYOZOANS Zoobotryon verticillatum AND Bugula dentata FROM THE BRAZILIAN COASTLINE. The chemical investigation of the MeOH extract from the bryozoan B. dentata MeOH yielded tambjamines A (1), C (3), D (4), K (6), aldehyde 8 and the new tambjamine J1(9), while the extract of its predator, the nudibranch Tambja stegosauriformis, yielded tambjamines C and K, along with aldehyde 8. Furodisinin lactone (11) was isolated from the nudibranch Hypselodoris lajensis, a compound previously isolated from Dysidea sponges. The alkaloid 2,5,6-tribromo-N-methylgramine (12) was isolated from the nudibranch Okenia zoobotryon and from its prey, the bryozoan Zoobotryon verticillatum, the only source of 12 previously known.

2-Acetylpyridine- and 2-benzoylpyridine-derived hydrazones and their gallium(III) complexes are highly cytotoxic to glioma cells

2-Acetylpyridine-phenylhydrazone (H2AcPh), its para-chlorophenylhydrazone (H2AcpClPh) and para-nitrophenylhydrazone (H2AcpNO(2)Ph) analogues, the corresponding 2-benzoylpyridine-derived hydrazones (H2BzPh, H2BzpClPh and H2BzpNO(2)Ph) and their gallium(III) complexes were assayed for their cytotoxic activity against U87 (expressing wild-type p53 protein) and T98 (expressing mutant p53 protein) glioma cells. IC50 values against both glioma cells and against the MRC5 (human fetal lung fibroblast) lineage were obtained for the hydrazones, but not for their gallium(III) complexes, due to their low solubility. Hydrazones were highly cytotoxic at nanomolar doses against U87 and T98 cells. The therapeutic indexes (TI = IC50MRC5/IC50glioma) were 2-660 for T98 cells and 28-5000 for U87 cells, indicating that the studied hydrazones could be good antitumor drug candidates to treat brain tumors. (C) 2012 Elsevier Masson SAS. All rights reserved.

INSECTICIDAL AND BEHAVIORAL EFFECTS OF SECONDARY METABOLITES FROM MELIACEAE ON BEMISIA TABACI (HEMIPTERA: ALEYRODIDAE)

We studied the effects of crude extracts and fractions of Azadirachta indica, Melia azedarach, Toona ciliata and Trichilia pallida on both egg and nymph mortality and embryonic development of Bemisia tabaci B biotype, using tomato plants grown in a greenhouse. Next, we studied the host selection behavioral effects on the adult whitefly under laboratory conditions. The dichloromethane extracts from all plant species and fractions of the extract from branches of T. pallida (EBTPD) and of the extract from leaves of T. ciliata (ELTCD) in dichloromethane caused mortality of nymphs, but neither affected egg viability. However, the branches of the ethanolic extract of A. indica increased the period of embryonic development of the B. tabaci. In addition, the tomato leaflets treated with the fraction of ELTCD dichloromethane (0.28%) were the least preferred by adults, reducing the number of insects resting on the tomato leaflets. The ELTCD methanol and EBTPD dichloromethane fractions inhibited B. tabaci oviposition. Thus, Meliaceae derivatives can contribute to the reduction of the B. tabaci population. The susceptibility of the B. tabaci to Meliaceae derivatives and the relevant behavioral changes of this pest are discussed.

Secondary metabolites isolated from Piper chimonantifolium and their antifungal activity

In this study, the CH2Cl2 extract from leaves of Piper chimonantifolium was subjected to several chromatographic separation procedures to afford one chromene (gaudichaudianic acid) as a major compound as well as two flavonoids (dihydrooroxylin and pinocembrin) and three steroids (sitosterol, sitosteryl palmitate and stigmasterol). The structures of all determined compounds were characterised by spectrometric analysis, mainly mass spectrometry and NMR, as well as their optical properties. This article describes the first phytochemical study of the leaves of P. chimonantifolium and an evaluation of the antifungal activity of its major compounds.

Microbial transformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus

The biotransformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus MT 5.3 yielded a rare derivative that was elucidated by spectrometric methods. The fungus led to the formation of a different product through an unusual epoxidation reaction between C4 and C5, formation of a C3,C10 ether bridge, and a methoxylation of the C1 of tagitinin C. The chemical structure of the product, namely 1 beta-methoxy-3 alpha-hydroxy-3,10 beta-4,5 alpha-diepoxy-8 beta-isobutyroyloxygermacr-11(13)-en-6 alpha,12-olide, is the same as that of a derivative that was recently isolated from the flowers of a Brazilian population of Mexican sunflower (Tithonia diversifolia), which is the source of the substrate tagitinin C. The in vitro cytotoxic activity of the substrate and the biotransformed product were evaluated in HL-60 cells using an MTT assay, and both compounds were found to be cytotoxic. We show that soil fungi may be useful in the biotransformation of sesquiterpene lactones, thereby leading to unusual changes in their chemical structures that may preserve or alter their biological activities, and may also mimic plant biosynthetic pathways for production of secondary metabolites.

Leishmanicidal activity in vitro of Musa paradisiaca L. and Spondias mombin L. fractions

Visceral leishmaniasis (VL) is a zoonotic disease characterized by infection of mononuclear phagocytes by Leishmania chagasi. The primary vector is Lutzomyia longipalpis and the dog is the main domestic reservoir. The control and current treatment of dogs using synthetic drugs have not shown effectiveness in reducing the incidence of disease in man. In attempt to find new compounds with leishmanicidal action, plant secondary metabolites have been studied in search of treatments of VL. This study aimed to evaluate the leishmanicidal activity of Musa paradisiaca (banana tree) and Spondias mombin (cajazeira) chemical constituents on promastigotes and amastigotes of L. chagasi. Phytochemical analysis by column chromatography was performed on ethanol extracts of two plants and fractions were isolated. Thin layer chromatography was used to compare the fractions and for isolation the substances to be used in vitro tests. The in vitro tests on promastigotes of L chagasi used the MTT colorimetric method and the method of ELISA in situ was used against amastigotes besides the cytotoxicity in RAW 264.7 cells. Of the eight fractions tested, Sm1 and Sm2 from S. mombin had no action against promastigotes, but had good activity against amastigotes. The fractions Mp1 e Mp4 of M. paradisiaca were very cytotoxic to RAW 264.7 cells. The best result was obtained with the fraction Sm3 from S. mombin with IC50 of 11.26 mu g/ml against promastigotes and amastigotes of 0.27 mu g/ml. The fraction Sm3 characterized as tannic acid showed the best results against both forms of Leishmania being a good candidate for evaluation in in vivo tests. (C) 2012 Published by Elsevier B.V.