Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L.

<p>Abstract</p> <p>Background</p> <p>The St John's Wort (<it>Hypericum perforatum</it>; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.</p> <p>Results</p> <p>An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC₅₀of 0.52 μg/ml), NO scavenging (6.11 μg/ml), superoxide scavenging (1.86 μg/ml), lipid peroxidation (0.0079 μg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.</p> <p>Conclusion</p> <p>LC-MS technique has been successfully applied for a quick separation and identification of the major components of <it>H. perforatum </it>fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, <it>H. perforatum </it>preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).</p

Essential oil composition and antifungal activity of Foeniculum vulgare Mill. obtained by different distillation conditions

The influence of different hydrodistillation conditions was evaluated from the standpoint of essential oil yield, chemical composition and antifungal activity from seeds of Foeniculum vulgare Mill. Three hydrodistillation conditions were considered. The main constituents of the oils were: (E)-anethole (72.27%-74.18%), fenchone (11.32%-16.35%) and methyl chavicol (3.78%-5.29%). The method of distillation significantly effected the essential oil yield and quantitative composition, although the antifungal activity of the oils against some fungi was only slightly altered. Copyright (C) 2003 John Wiley Sons, Ltd.nul

LIGNICOLOUS FUNGI AS POTENTIAL NATURAL SOURCES OF ANTIOXIDANTS

Abstract- As a result of an interest in natural derived metabolites around the world, higher fungi (Basidiomycotina) have taken on great importance in biochemical investigations. A large number of structurally divergent compounds- both cellular components and secondary metabolites- have been extracted and found to possess significant biological activity, such as an immunomodulative effect on the human body. Effects of fungal biomolecules as potential natural antioxidants have not been examined so far. Biochemical analysis have included in vitro testing of the influence of different extracts (water, methanol, chloroform) of selected fungal sporocarps on Fe 2+ /ascorbate-induced lipid peroxidation (LP) in a lecithin liposome system by TBA assay, as well as various other procedures. Qualitative analysis by TLC revealed a distinction both between different extracts of the same fungal species and between similar extracts of different species. The results obtained on antioxidative activities (LP inhibition and &quot;scavenging &quot; activity) indicate that MeOH extracts manifested a degree of activity higher than that of CHCl 3 extracts with respect to antioxidative activity, the extracts can be ranged in the following declining order: Ganoderma lucidum, Ganodermaapplanatum, Meripilus giganteus, and Flammulina velutipes. The obtained results suggest that the analyzed fungi are of potential interest as sources of strong natural antioxidants in the food and cosmetics industries, whereas synthetic ones have proved to be carcinogenic

Essential oil composition and antifungal activity of Foeniculum vulgare Mill. obtained by different distillation conditions

The influence of different hydrodistillation conditions was evaluated from the standpoint of essential oil yield, chemical composition and antifungal activity from seeds of Foeniculum vulgare Mill. Three hydrodistillation conditions were considered. The main constituents of the oils were: (E)-anethole (72.27%-74.18%), fenchone (11.32%-16.35%) and methyl chavicol (3.78%-5.29%). The method of distillation significantly effected the essential oil yield and quantitative composition, although the antifungal activity of the oils against some fungi was only slightly altered. Copyright (C) 2003 John Wiley Sons, Ltd.nul

Combined effects of plant extracts and xenobiotics on liposomal lipid peroxidation. Part 1. Marigold extract-ciprofloxacin/pyralene

Methanolic (70%) extracts of marigold flower, leaf, stem and root, after solvent removal, were successively extracted with ether, chloroform, ethyl acetate, and n-butanol - the residue being the corresponding aqueous extract. All five extracts were evaporated to dryness and then dissolved in 50% EtOH to obtain 6% (w/v) solutions. These solutions, either alone or in combination with different doses of ciprofloxacin or pyralene, were used to study their effect on liposomal lipid peroxidation (LPx) induced by Fe 2+ and ascorbic acid. The majority of the extracts of marigold flower, leaf and stem showed an antioxidant effect, the butanol extract of roots exhibiting a pro-oxidative character. At lower doses, ciprofloxacin did not affect LPx, at higher doses a dose-dependent increase in LPx was observed. The extracts in combination with ciprofloxacin showed a protective effect, which was also dose-dependent. The butanolic extract of root snowed no synergistic effect with ciprofloxacin. Pyralene alone exhibited a pro-oxidative action on liposomal LPx. Aqueous and butanolic extracts of flower, leaf, and stem had a protective effect in combination with pyralene. The butanolic extract of root showed a pro-oxidative synergistic effect with pyralene

Optimization of extraction conditions for secondary biomolecules from various plant species

Extraction of plant secondary metabolites is an essential step in isolation of natural products. Non-optimized extraction conditions can lead to losses, degradation and modification of the biomolecules. In this paper, the influence of different solvent mixtures, solvent amounts, temperature, extraction time, and procedures for defatting on yield and profile of various classes of secondary metabolites was investigated. Rumex alpinus was used for the extraction of anthraquinones, Glycine max for isoflavonoids, Chaerophyllum bulbosum for flavonoids and phenolic acids, Anthriscus sylvestris for lignans and coumarins, alkaloids were extracted from Lupinus albus and sesquiterpene lactones from Artemisia absinthium. Extraction efficiency was evaluated by use of LC-DAD-ESI-MS/MS. The compromise extraction solvent for all of the examined compounds is 80 % methanol, mixed in ratio 13 : 1 with plant material. Maceration should last for six hours, repeated four times with fresh solvent. Defatting of the extracts does not lead to significant losses of the compounds of interest. It is acceptable to use extraction and evaporation temperature of 60ºC, while the extracts should be stored in the dark, on -20ºC. [Projekat Ministarstva nauke Republike Srbije, br. 172058

Chemical analysis and antifungal activity of Thymus striatus

The essential oil composition from Thymus striatus collected from Mountain Orjen (Montenegro) has been investigated by gas chromatography-mass spectrometry. Thymol, gamma-terpinene and p-cymene were found to be the major components. Furthermore, the oil and its major component, thymol, were analysed for potential antifungal activity against plant, animal and human pathogenic fungi from different genera by a macrodilution test. The oil exhibited a strong inhibitory effect against all fungi investigated. Copyright (C) 2004 John Wiley Sons, Ltd.nul

Combined effects of plant extracts and xenobiotics on liposomal lipid peroxidation. Part 4. Dandelion extract - Ciprofloxacin/pyralene

The article describes a study of the protective effect of dandelion (Taraxacum officinale L. Asteraceae) in combination with two xenobiotics: ciprofloxacin and pyralene. For that purpose, methanolic extracts of the plant flower, leaf, stem, and root upon removal of the solvent were successively extracted with ether, chloroform, ethyl acetate, and n-butanol. The extracts were evaporated to dryness and then dissolved in 50% ethanol to obtain 6% (w/v) solutions. These solutions, either alone or in combination with different doses of ciprofloxacin or pyralene, were used to study their effect on liposomal lipid peroxidation (LPx) induced by Fe 2+ and ascorbic acid. It appeared that almost all the individual extracts exhibited an antioxidant effect and in combination with pyralene decreased its pro-oxidative action on liposomal LPx. At lower concentrations, ciprofloxacin alone did not exhibit an antioxidant effect, but at higher concentrations it acted as a pro-oxidant, the effect being lowered by the presence of dandelion extracts. It is interesting to note that the extract of dandelion stem exhibited a very strong protective effect

Antimicrobial and antioxidant activities of Melissa officinalis L. (Lamiaceae) essential oil

The present study describes antimicrobial and free radical scavenging capacity (RSC) together with the effects on lipid peroxidation (LP) of Melissa officinalis essential oil. The chemical profile of essential oil was evaluated by the means of gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). RSC was assessed measuring the scavenging activity of essential oil on the 2,2-diphenyl-1-picrylhydrazyl (DPPH.) and OH. radicals. The effect on LP was evaluated following the activities on Fe2+/ascorbate and Fe2+/H2O2 systems of induction, The antimicrobial activity was tested against 13 bacterial strains and six fungi. The examined essential oil exhibited very strong RSC, reducing the DPPH radical formation (IC50 = 7.58 mug/mL) and OH radical generation (IC50 = 1.74 mug/mL) in a dose-dependent manner. According to the GC-MS and TLC (dot-blot techniques), the most powerful scavenging compounds were monoterpene aldehydes and ketones (neral/geranial, citronellal, isomenthone, and menthone) and mono- and sesquiterpene hydrocarbons (E-caryophyllene). Very strong inhibition of LP, particularly in the Fe2+/H2O2 system of induction (94.59% for 2.13 mug/mL), was observed in both cases, also in a dose-dependent manner. The most effective antibacterial activity was expressed on a multiresistant strain of Shigella sonei. A significant rate of antifungal activity was exhibited on Trichophyton species.nul

Antimicrobial and antioxidant activities of Melissa officinalis L. (Lamiaceae) essential oil

The present study describes antimicrobial and free radical scavenging capacity (RSC) together with the effects on lipid peroxidation (LP) of Melissa officinalis essential oil. The chemical profile of essential oil was evaluated by the means of gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). RSC was assessed measuring the scavenging activity of essential oil on the 2,2-diphenyl-1-picrylhydrazyl (DPPH.) and OH. radicals. The effect on LP was evaluated following the activities on Fe2+/ascorbate and Fe2+/H2O2 systems of induction, The antimicrobial activity was tested against 13 bacterial strains and six fungi. The examined essential oil exhibited very strong RSC, reducing the DPPH radical formation (IC50 = 7.58 mug/mL) and OH radical generation (IC50 = 1.74 mug/mL) in a dose-dependent manner. According to the GC-MS and TLC (dot-blot techniques), the most powerful scavenging compounds were monoterpene aldehydes and ketones (neral/geranial, citronellal, isomenthone, and menthone) and mono- and sesquiterpene hydrocarbons (E-caryophyllene). Very strong inhibition of LP, particularly in the Fe2+/H2O2 system of induction (94.59% for 2.13 mug/mL), was observed in both cases, also in a dose-dependent manner. The most effective antibacterial activity was expressed on a multiresistant strain of Shigella sonei. A significant rate of antifungal activity was exhibited on Trichophyton species.nul