Antioxidant activity of papaya seed extracts

The antioxidant activities of the ethanol, petroleum ether, ethyl acetate, n-butanol and water extract fractions from the seeds of papaya were evaluated in this study. The ethyl acetate fraction showed the strongest DPPH and hydroxyl free radical-scavenging activities, and its activities were stronger than those of ascorbic acid and sodium benzoate, respectively. The n-butanol fraction demonstrated the greatest ABTS? radicals scavenging activity. The ethyl acetate fraction and the n-butanol fraction not only showed higher antioxidant activities than the petroleum ether fraction, water fraction and ethanol fraction, but also showed higher superoxide anion and hydrogen peroxide radicals scavenging activities than those of the other extract fractions. The high amount of total phenolics and total flavonoids in the ethyl acetate and n-butanol fractions contributed to their antioxidant activities. The ethyl acetate fraction was subjected to column chromatography, to yield two phenolic compounds, p-hydroxybenzoic acid and vanillic acid, which possessed significant antioxidant activities. Therefore, the seeds of papaya and these compounds might be used as natural antioxidants.     

Comparative chemical composition and variability of biological activity of methanolic extracts from Hypericum perforatum L

The biovariability of Hypericum perforatum L. (St. John's Wort) grown wild in Calabria and Sardinia (Italy) was reported with the aim to characterize the species through the isolation, detection, and quantitative evaluations of chemical markers (hypericin, quercetin, rutin) by HPLC analysis. Antioxidant activity of the methanolic H. perforatum extracts showed that the Calabrian samples were more active than those from Sardinia. The antibacterial activity evidenced the best performance on the gram positive bacteria with a MIC value of 50 microg/mL. Moreover, antifungal activity of all the extracts was also tested which showed interesting results particularly on the phytopathogene fungus P. ultimum. The variability shown by the samples could be attributed to environmental factors such as chemical-physical properties, composition of the soil, geographical coordinate, altitude, and solar exposure. The phytochemical analysis and the biological activity data suggested a possible use of H. perforatum extracts in the alimentary, cosmetic, and pharmaceutical fields.     

Antioxidant activity of extracts from Euryale ferox seed

Euryale ferox has been widely used in traditional oriental medicine to treat a variety of illness. However, very little is known about the cellular actions by which this plant mediates its therapeutic effects. Various aspects of antioxidant activity were evaluated in total extracts and fractions derived from Euryale ferox. Total extracts (IC50 5.6 microg/ml) showed relatively high level radical scavenging activity toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and also enhanced viability of Chinese hamster lung fibroblast (V79-4) cells under exposure to oxidative agents. Upon further fractionation, the highest levels of DPPH radical scavenging and lipid peroxidation inhibitory activities were found in the ethyl acetate and butanol fractions. The ethyl acetate fractions, the butanol fractions, and total extracts of Euryale ferox also dose-dependently enhanced the activities of superoxide dismutase, catalase and glutathione peroxidase in V79-4 cells. Of these three antioxidant enzymes, glutathione peroxidase activity was most strongly induced. Taken together, our findings show that Euryale ferox contains a significant antioxidant activity and that specific components in the ethyl acetate and butanol fractions may play an important role in mediating these antioxidant properties.     

Determination of singlet oxygen quenching and protection of biological systems by various extracts from seed of Rumex crispus L

The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect and total phenolic contents were evaluated for the screening of singlet oxygen ((1)O(2)) quenching efficacy of various seed extracts from Rumex crispus L. The butanol and ethyl-acetate extracts displayed remarkable effect of DPPH as compared to positive control ascorbic acid. The concentrations (QC(50)) of butanol and ethyl-acetate extracts required to exert 50% reducing effect on (1)O(2) were found to be 116 and 82 μg mL(-1), respectively. Both extracts were also found to protect the in vitro biological system from the detrimental effect of (1)O(2) on type II photosensitization in Escherichia coli, red blood cell, lactate dehydrogenase and histidine. Among all the tested extracts, the ethyl-acetate and butanol extracts contained higher amount of total phenolic contents. The results suggest that our study may contribute to the development of new bioactive products with potential applications to reduce photo-produced oxidative stress involving reactive oxygen species in living organisms.     

Composition of essential oil and biological activity of extracts of Viola odorata L. from central Iran

Essential oil composition of the leaves of Viola odorata L. growing wild in Kashan, central Iran, was extracted by hydro distillation-solvent extraction method and analysed using GC-MS technique. The analysis revealed the presence of 25 identified compounds, representing 92.77% of the oil with butyl-2-ethylhexylphthalate (30.10%) and 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H)-benzofuranone (12.03%) being the two main components. Several components were identified for the first time in this chemotype of V. odorata. Antioxidant and antibacterial activities of the oil, methanol and chloroform extracts were also evaluated for the first time in this research work.     

Chemical and biological activity of leaf extracts of Chromolaena leivensis

The flavonoids 3,5-dihydroxy-7-methoxy-flavanone, 3,5-dihydroxy-7-methoxyflavone and 3,5,7-trihydroxy-6-methoxyflavone were isolated from the leaves of C. leivensis. Preliminary observations in K562 cells (human erythroleukemia) using the trypan blue test, showed a 90% viability at a concentration of 100 microg/mL; however, further testing of the flavonoids at concentrations of 25, 50 and 100 microg/mL showed toxicity affecting the morphology of human erythroleukemia cells (K562) and human melanoma cells (A375). Induction of apoptosis was produced by 3,5-dihydroxy-7-methoxyflavone at 72 hours after treatment with arrest in the G2 / M phase of the cell cycle. The A375 cells treated with 50 microg/mL of 3,5-dihydroxy-7-methoxy-flavanone for 24, 48 and 72 hours, display effects on the behavior of the cell cycle. The flavonoid 3,5-dihydroxy-7-methoxyflavone has activity on the mitochondrial membrane at concentrations of 25, 50 and 100 microg/mL, at time intervals of 8 to 12 hours. The flavonoids 3,5-dihydroxy-7-methoxy-flavanone and 3,5-dihydroxy-7-methoxyflavone at a concentration of 25 microg/mL increased the expression of costimulatory molecules corresponding to the phenotype presented by mature dendritic cells with differentiation markers CD40, CD83, CD86 and HLA-DR. The two flavonoids at concentrations between 0.39 and 100 microg/mL slightly increased the proliferation of peripheral blood mononuclear cells in the presence and in the absence of phytohemagglutinin. These flavonoids at concentrations of 50 and 100 microg/mL slightly increased the proliferation of fibroblasts.     

Antitumor activity of stilbenoids and flavonoids isolated from Acanthopanax brachypus

This report is the first to detail the antitumor activity of Acanthopanax brachypus, a species well recognized by eastern folk medicine. Four stilbeniods and nine flavonoids have been isolated from stem bark of the plant. The isolates have been tested for their antitumor activity against selected human cancer cell lines (HgpG-2, MCF-7, K-562, and A-549). Even though three of the compounds have shown high to moderate cytotoxicity against certain cell lines (IC₅₀ of 4.5 to 6.5 μg/mL), in most of the experiments little or no anticancer activity has been revealed.     

Chemical composition and biological activity of the volatile extracts of Achillea millefolium

In this study, flowering aerial parts of wild Achillea millefolium growing on the Mediterranean coast (Sardinia Island, Italy) and on the Atlantic coast (Portugal- Serra de Montemuro) were used as a matrix for supercritical extraction of volatile oil with CO2 (SFE). The collected extracts were analyzed by GC-FID and GC-MS methods and their composition were compared with that of the essential oil isolated by hydrodistillation. A strong chemical variability in essential oils depending on the origin of the samples was observed. The results showed the presence of two type oils. The Italian volatile extracts (SFE and essential oil) are predominantly composed by alpha-asarone (25.6-33.3%, in the SFE extract and in the HD oil, respectively), beta-bisabolene (27.3-16.6%) and alpha-pinene (10.0-17.0%); whereas the main components of the Portuguese extracts are trans-thujone (31.4-29.0%), trans-crhysanthenyl acetate (19.8-15.8%) and beta-pinene (1.2-11.1%). The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, C. tropicalis, C. krusei, C. guillermondii, C. parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, T. mentagrophytes, T. mentagrophytes var. interdigitale, T. verrucosum, Microsporum canis, M. gypseum, Epidermophyton floccosum, Aspergillus niger, A. fumigatus and A. flavus. The oils showed the highest activity against dermatophyte strains, with MIC values ranging from 0.32-1.25 microL mL(-1).     

聚异戊二烯基三胺的合成及生理活性评价

设计、合成了一系列聚异戊二烯基三胺化合物,目标化合物结构均经过核磁共振谱、质谱及元素分析确认;利用MTT法测试了目标化合物对人白血病细胞K562和人肝癌细胞Bel-7402的体外抗肿瘤活性.结果表明,目标化合物对两种肿瘤细胞的生长均有较强的抑制活性.     

Three new diterpenes and the biological activity of different extracts of Jasonia montana

Three new diterpenes, namely jasonin-a (1), jasonin-b (2), and jasonin-c (3) were isolated from the aerial parts of Jasonia montana (Asteraceae). Their structures were elucidated on the basis of spectral data as [(1E)-2-((2S)-1,2,5-trimethylbicyclo[3.2.l]octan-8-yl)vinyl] benzene-3-carboxylic acid (1), [3-((2S, 5S)-1,2, 5-trimethylcycloheptanyl)propyl]benzene-3-carboxylic acid (2), and [(1E)-3-((7R)-1,7-dimethy-4-methylenecycloheptanyl)prop-1-enyl] benzene-3-carboxylic acid (3). In addition, the previously reported 5,7,3'-trihydroxy-3,6,4'-trimethoxy flavone designated as centaureidin (4), was also isolated and characterized from this source. The different extracts of the plant were also screened for hypoglycemic, antidiabetic, and antimicrobial activities, wherein the petroleum ether and ethanolic extracts exhibited hypoglycemic and antidiabetic activity, and the petroleum ether and chloroform extracts showed antimicrobial activity.     

Antifungal activity of mango peel and seed extracts against clinically pathogenic and food spoilage yeasts

The antioxidant and antifungal (antiyeast) properties of mango (Mangifera indica) peel and seed by-products were investigated. Nine extracts were obtained using three cultivars and two extraction methods. Significant differences between cultivars and extraction methods were detected in their bioactive compounds and antioxidant activity. The antifungal property was determined using agar diffusion and broth micro-dilution assays against 18 yeast species of the genera Candida, Dekkera, Hanseniaspora, Lodderomyces, Metschnikowia, Pichia, Schizosaccharomyces, Saccharomycodes and Zygosaccharomyces. All mango extracts showed antifungal activity. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) values were lower for seed than for peel extracts. MICs and MFCs ranged from values <0.1 to 5 and 5 to >30 mgGAE/mL, respectively. The multivariate analysis showed a relationship between antifungal activity, the capacity to inhibit lipid peroxidation and total phenol content. These properties were associated with high levels of proanthocyanidins, gallates and gallotannins in the extracts.     

Neutral lipids, phospholipids, and biological activity of extracts from Zygophyllum oxianum

The chemical composition of lipid extracts from aerial parts of Zygophyllum oxianum was determined by GC and TLC. The yield of total lipids was 0.75% in leaves, 0.33% in stems, and 0.49% in fruit calculated for fresh plant mass. Phospholipids were represented by nine classes, of which phosphatidylcholine dominated (55.8% in leaves, 56.4% in stems, 63.7% in fruit of total PL). The n-BuOH extract from the plant aerial part exhibited noticeable antifungal activity. The CHCl₃:MeOH (2:1) extract from leaves and stems exhibited pronounced in vitro cytotoxicity against human bladder carcinoma cell line 5637 with IC₅₀ 6.2 μg/mL.     

Bioassay-guided fractionation of antifertility components of castorbean (Ricinus communis L.) seed extracts

In the present study, the aether extracts of castorbean seed (AEC), which possessed antifertility activity and contraceptive efficacy in female and male rodents, were evaluated for their in vitro inhibitory activity in the primary cultured rat decidual stromal cells (DSC). A bioassay-guided fractionation technique was used to separate active components from crude extracts. A colorless crystal showed a significant inhibitory activity (IC(50) = 63.84 +/- 3.04 microg mL(-1), r = +0.9478). The chemical analysis of the colorless crystal by capillary gas chromatography-mass spectrometry (GC-MS) revealed that the colorless crystal was a mixture of five components: four phytosterols which were ergost-5-en-3-ol (6.10%), stigmasterol (35.80%), gamma-sitosterol (44.77%), and fucosterol (8.40%); and one probucol analog (4.93%). It was presumed that gamma-sitosterol may be the main component contributing to inhibit the viability of DSC.     

Synthesis of peptidoglycan fragments and evaluation of their biological activity

The peptidoglycan (PG) bacterial cell wall glycoconjugate has been well known as a strong immunopotentiator. Partial structures of PG were chemically synthesized for elucidation of precise biological activities. Effective construction of distinct repeating glycans of PG was accomplished by the coupling of a key disaccharide glucosaminyl-beta(1-4)-muramic acid unit. Stereoselective glycosylation of disaccharide units was achieved by neighboring group participation of the N-Troc (Troc = 2,2,2-trichloroethoxycarbonyl) group and appropriate reactivity of N-Troc-glucosaminyl trichloroacetimidate. By using an efficient synthetic strategy, mono-, di-, tetra- and octasaccharide fragments of PG were synthesized in high yields. The biological activity of synthetic fragments of PG was evaluated by induction of tumor necrosis factor-alpha (TNF-alpha) from human monocytes, and toll-like receptor 2 (TLR2) and Nod2 dependencies by using transfected HEK293 cells, respectively. Here we reveal that TLR2 was not stimulated by the series of synthetic PG partial structures, whereas Nod2 recognizes the partial structures containing the MDP moiety.     

Practical synthesis of hydroxychromenes and evaluation of their biological activity

A simple and efficient seven steps synthesis of brodifacoum and difethialone from phenylacetyl chloride is described. The key synthetic strategies involve Friedel-Crafts acylation, intramolecular ring cyclization and condensation reaction in the presence of Br?nsted-Lowry acids. It was found that brodifacoum showed favorable inhibiting activities on LPS-stimulated nitrite production in BV-2 microglia cells. Brodifacoum exhibited superior anti-inflammatory effects than difethialone. We expect that an efficient linear synthesis of 4-hydroxycoumarin derivatives and key fragments that are useful agents for the modulation of inflammation as well as inhibition of coagulation will be of practical use.     

Synthesis and biological activity evaluation of new thiazolidinone-diclofenac hybrid molecules

Abstract

A novel series of [2-(2,6-dichlorophenylamino)-phenyl]-acetic acid N`-3-(substituted)-4-thiazolidin-5-ylidenemethyl-hydrazide derivatives has been designed and synthesized. The structures of synthesized compounds were confirmed by their <sup>1</sup>H NMR, <sup>13</sup>C NMR and LCMS spectroscopic data. Target compounds were screened for their in vitro anticancer activity according to US NCI protocols, in vitro trypanocidal activity toward Trypanosoma brucei brucei (Tbb) and evaluated for anti-inflammatory activity on the carrageenan edema model in rats. Biological screening data led to identification of compounds 3.3 ([2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid N`-(4-oxo-2-thioxo-thiazolidin-5-ylidenemethyl)-hydrazide) and 3.7 ([2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid N`-(4-oxo-2-thioxo-3-(3-trifluoromethylphenyl)thiazolidin-5-ylidenemethyl)-hydrazide) which demonstrated moderate antitumor activity on the non-small-cell lung cancer NCI-H522 and colon cancer HCT-116 cell lines. Several hit compounds (3.2, 3.4) exhibited the promising and significant inhibition growth of the parasites at micromolar concentrations (IC₅₀ values of 4.8 and 7.06?μM, respectively). The synthesized compounds also demonstrated considerable anti-inflammatory effect comparable to the reference non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac sodium or ketorolac tromethamine.     

新型苯并咪唑衍生物的合成及生物活性研究

以取代苯酚为原料,合成8个新型的2-苯氧甲基苯并咪唑类化合物,通过1H-NMR和HRMS确认其结构。MTT法测试其抗肿瘤活性,实验结果表明,大部分化合物具有较好的广谱抗肿瘤效果,其中化合物2h对大多数肿瘤细胞株的IC50值均达到了低微摩尔水平,对人胰腺癌(BxPC-3)的IC50达到3.6μM。试管二倍稀释法测试其抗菌活性,实验结果表明,目标化合物显示出抗菌活性,化合物2a对粪肠球菌和金黄色葡萄球菌的MIC达到16μg/mL。     

Allelopathic activity and chemical constituents of extracts from roots of Euphorbia heterophylla L

Euphorbia heterophylla L. is regarded as a major weed worldwide. Its high aggressiveness in agricultural environment prompted us to investigate the allelopatic activity and chemical constitution of extracts from roots of this plant. Hexane extract showed low phytotoxic activity. Methanol extract at 2.0 mg mL^?1 inhibited 100% of germination, root and shoot growth of the indicator plants Sorghum bicolor and Lactuca sativa. β-sitosterol, stigmasterol, and esters of lupeol, germanicol, taraxasterol, pseudotaraxasterol, α-amyrin and β-amyrin were isolated from the hexane extract and their structures elucidated on the basis of MS and ¹H, ¹³C and DEPT-135 NMR data. GC-MS analysis of the derivatized methanol extract allowed for identifying a series of allelopathic organic acids potentially involved in allelopathic interactions of E. heterophylla. This is the first study on the allelopathic activity of extracts and identification of metabolites from roots of E. heterophylla.     

Antifungal activity and phytochemical screening of extracts from Phoenix dactylifera L. cultivars

In this study, the rachis extracts of eight date palm Phoenix dactylifera L. cultivars were analysed by phytochemical screening and bioautography on Fusarium oxysporum f. sp. albedinis (Foa). The choice of cultivars was based on their reaction to Foa (resistant, tolerant and sensitive). Phytochemical screening was realised for flavonoids, tannins, alkaloids and coumarins. Antifungal effects were mostly represented by dichloromethanic extracts (seven out of nine inhibition zones). The best results were represented by the dichloromethanic extract of the cultivar 'Bent-Cherk' rachis (6.50?±?1.41?mm) and the ethyl acetate extract of the cultivar 'Rotbi' rachis (6.00?±?1.41?mm). The date palm cultivars presented some similarities concerning phytochemical screening results related to their resistance or sensibility to Foa. From the correlation between phytochemical screening and bioautography, it was observed that the majority of bioactive compounds against Foa seem to be polyphenols. Thus, the natural defence mechanism in vivo against Foa is probably related to the action of polyphenols. The difference between resistant, tolerant and sensitive cultivars is related to their mechanism of action.     

Asymmetric total synthesis of danicalipin A and evaluation of biological activity

Asymmetric total synthesis of danicalipin A was achieved. The synthesis was characterized by diastereoselective introduction of chlorine atoms. Biological activities with synthetic danicalipin A, its enantiomer, and racemate were also evaluated toward brine shrimp. Both enantiomers of danicalipin A showed almost the same activity.