Isolation and characterization of alkyl peroxy radical scavenging compound from leaves of Laurus nobilis. (1/21)

EtOH-soluble fraction from leaves of Laurus nobilis (bay leaves) possessed the highest alkyl peroxy radical (ROO*) scavenging activity among 120 kinds of herbs and edible plants, using the bioassay system which could determine the viability of Staphylococcus aureus 209p by ROO* cytotoxicity. After EtOH-soluble fraction was partitioned with chloroform, ethylacetate, n-butanol and water, the ethylacetate-soluble fraction (L-EA) possessing the highest scavenging activity was further fractionated by Silica gel, Sephadex LH-20 and semi-preparative HPLC analysis on micro-Bondapak C18 reverse phase, and a major flavonol (L-EA-IIa-3-H2) in leaves of L. nobilis was isolated. According to the ultraviolet-visible absorption spectra, L-EA-IIa-3-H2 was thought to be 3,5,7,3'-OH or 3(5),7,3',4'-OH flavonol. After acid hydrolysis of the fraction, L-EA-IIa-3-H2 was found to consist of quercetin and glucose, and was confirmed by one- or two-dimensional (1D or 2D)-NMR to be isoquercitrin. In addition, the ROO* scavenging activity of L-EA-IIa-3-H2 was supported by ESR and its activity was found to be comparable to that of other well-known antioxidants such as epigallocatechin and resveratrol, and higher than that of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and ascorbic acid.  (+info)

A new method to determine the oxygen concentration inside the sapwood of trees. (2/21)

Research into the short-term fluctuations of oxygen concentrations in tree stems has been hampered by the difficulty of measuring oxygen inside tissues. A new method, which is based on fluorescence quenching of a ruthenium complex in the presence of oxygen, has been applied to measure changes of oxygen concentration in the sapwood of trees. During a field day-course oxygen increased with the radiation load and fell during the night (in Fagus orientalis from 20.3% in the afternoon to 17.5% in the morning next day). In a greenhouse experiment the sapwood oxygen concentration of Laurus nobilis could be influenced by flooding the root system. The very fast response, high resolution (better than 0.1%), easy calibration, and dependence only on oxygen and temperature make the technique well suited for measurements of oxygen concentrations in the sapwood.  (+info)

Inhibitory mechanism of costunolide, a sesquiterpene lactone isolated from Laurus nobilis, on blood-ethanol elevation in rats: involvement of inhibition of gastric emptying and increase in gastric juice secretion. (3/21)

Basic inhibitory mechanisms of costunolide and its active component, alpha-methylene-gamma-butyrolactone (alpha-MGBL), on blood-ethanol elevation were investigated in rats. In normal rats, blood-ethanol elevation (30 min later) induced by 20% (v/v) ethanol [5 ml/kg, per os (p.o.)] was strongly inhibited by pretreatment (30 min earlier) with costunolide and alpha-MGBL (50 mg/kg, p.o.). In pylorus-ligated rats given ethanol, blood-ethanol level (30 min) was barely elevated compared with that of normal rats. Neither costunolide nor alpha-MGBL affected the blood-ethanol elevation in pylorus-ligated rats or that induced by intraperitoneal and intraduodenal ethanol administration. Moreover, these compounds given orally induced no irreversible changes in alcohol dehydrogenase activity in rat liver. We continuously investigated the rate of gastric emptying in rats given various test meals. Costunolide and alpha-MGBL suppressed gastric emptying in rats given 20% ethanol and 1% sodium carboxymethyl cellulose. alpha-MGBL (50 mg/kg), but not costunolide, suppressed gastric emptying in 20% glucose-loaded rats. In an in vitro experiment, alpha-MGBL contracted the pylorus strip at a high concentration (20 mM), which was the estimated concentration in the stomach when the substance was given orally in vivo. These findings suggested that alpha-MGBL constricted the pylorus and caused delay of gastric emptying. Moreover, both compounds increased gastric fluid secretion with pepsin and mucus. In conclusion, the inhibitory effects of costunolide and alpha-MGBL on blood-ethanol elevation were based on inhibition of gastric emptying and dilution of the ethanol concentration by the increased gastric fluid.  (+info)

Trypanocidal terpenoids from Laurus nobilis L. (4/21)

Trypanocidal constituents of dried leaves of Laurus nobilis L. (Lauraceae) were examined. Activity-guided fractionation of the methanol extract resulted in the isolation of two guaianolides, dehydrocostus lactone (1) and zaluzanin D (2), and a new p-menthane hydroperoxide, (1R,4S)-1-hydroperoxy-p-menth-2-en-8-ol acetate (3). The minimum lethal concentrations of these compounds against epimastigotes of Trypanosoma cruzi were 6.3, 2.5, and 1.4 microM, respectively.  (+info)

Evaluation of wound healing activity of Allamanda cathartica. L. and Laurus nobilis. L. extracts on rats. (5/21)

BACKGROUND: Allamanda cathartica. L. is a perennial shrub used in traditional medicine for treating malaria and jaundice. Laurus nobilis. L. is a tree and has been used for its astringent, healing and diuretic properties. The objective of this study was to investigate the aqueous extracts of Allamanda and Laurus nobilis to evaluate their wound healing activity in rats. METHODS: Excision and incision wound models were used to evaluate the wound healing activity of both the extracts on Sprague Dawley rats. In each model, animals were divided into four groups of 10 animals each. In both the model, group 1 served as control and group 2 as reference standard. In an excision wound model, group 3 animals were treated with Allamanda (150 mg kg(-1) day(-1)) and group 4 animals were treated with Laurus nobilis (200 mg kg(-1) b.w day(-1)) for 14 days respectively. In the case of incision wound model, group 3 and 4 animals were treated with the extracts of Allamanda and Laurus respectively for 10 days. The effects of vehicles on the rate of wound healing were assessed by the rate of wound closure, period of epithelialisation, tensile strength, weights of the granulation tissue, hydroxyproline content and histopathology of the granulation tissue. RESULTS: The aqueous extract of Allamanda promoted wound healing activity significantly in both the wound models studied. High rate of wound contraction (P < .001), decrease in the period of epithelialisation (10.2 +/- 0.13), high skin breaking strength (440.0 +/- 4.53), significant increase in the weight of the granulation tissue (P < .001) and hydroxyproline (P < .001) content were observed in animals treated with the aqueous extract of Allamanda. Histological studies of the granulation tissue from the Allamanda treated group showed the presence of a lesser number of inflammatory cells, and increased collagen formation than the control. In Laurus nobilis treated animals, the rate of wound contraction, weight of the granulation tissue and hydroxyproline content were moderately high (P < .05). The histological study of the granulation tissue of the Laurus nobilis treated animals showed larger number of inflammatory cells, and lesser collagen when compared with the Allamanda treated group of animals. However, it was better than the control group of animals. CONCLUSION: The data of this study indicated that the leaf extract of Allamanda possesses better wound healing activity than the Laurus nobilis and it can be used to treat different types of wounds in human beings too.  (+info)

Two new sesquiterpene lactones from the leaves of Laurus nobilis. (6/21)

As a part of our ongoing interest in new bioactive compounds from natural sources, we studied Laurus nobilis (Lauraceae). This plant is widespread in the Mediterranean area and is used for medicinal and economic purposes. Chromatographic separations on active extracts led to the isolation of two new sesquiterpene lactones, 5a,9-dimethyl-3-methylene-3,3a,4,5,5a,6,7,8-octahydro-1-oxacyclopenta[c]azulen-2- one (1) and 3beta-chlorodehydrocostuslactone (2). The structures of the new compounds were identified by 1D and 2D NMR experiments, as well as high resolution mass spectrometry. The cytotoxic activity was also evaluated against three different tumor cell lines of human origin.  (+info)

Comparative chemical composition and antioxidant activities of wild and cultivated Laurus nobilis L. leaves and Foeniculum vulgare subsp. piperitum (Ucria) coutinho seeds. (7/21)

The chemical composition and antioxidant activities of wild and cultivated Laurus nobilis leaves and Foeniculum vulgare subsp. piperitum seeds were determined. Differences were found in the total phenolic content of fennel. GC-MS analysis of the non polar fractions showed a different composition between wild and cultivated plants. Cultivated laurel had a high content of terpenes such as linool, alpha-terpinol, alpha-terpinyl acetate, thymol, caryophyllene, aromandrene, selinene, farnesene, and cadinene, while wild laurel had a high content of eugenol and methyl eugenol, vitamin E, and sterols. The antioxidant potential of the extracts was determined using three complementary methods. Wild plants showed greater radical scavenging activity than the cultivated plants. The extracts also exhibited a significant antioxidant capacity also in the beta-carotene-linoleic acid test system. A high level of antioxidant activity was observed in wild laurel (IC50 = 1 microg/ml). Significant antioxidant activity measured in bovine brain was observed in wild laurel.  (+info)

Gerronema wildpretii sp. nov. (Agaricales, Basidiomycetes) a new species from the Canary Islands. (8/21)

Gerronema wildpretii, collected in climactic sites of the monteverde forest of the Canary Islands is described and illustrated. Its macro- and microscopic features delimit this taxon as a new species.  (+info)

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