1,720,967 research outputs found
Antimicrobial properties of the linalool-rich essential oil of Hyssopus officinalis L. var decumbens (Lamiaceae)
No full textThe antimicrobial activity of essential oil of Hyssopus officinalis L. var decumbens and Hyssopus officinalis L. was studied taking account of their chemical composition determined by GC and GC-MS. Pinocamphone and isopinocamphone were present in H. officinalis according to the ISO 9841 Standard (1991 E) but they were lacking in var. decumbens, where linalol (51.7%), 1,8-cineole (12.3%) and limonene (5.1%) instead are predominant. The disc diffusion tests carried out on Staphylococcus aureus and Enterococcus spp. and onKlebsiella oxytoca, Escherichia coli, Proteus mirabilis, Pseudomonas spp, and two strains of Salmonella spp., showed an antimicrobial activity generally negligible for H. officinalis, but broader, and in a few cases more evident for var. decumbens. All yeasts tested (seven strains of Candida) were strongly inhibited by both species. The effect of var. decumbens was generally bactericidal
FARMACI DI ORIGINE VEGETALE AD AZIONE VASOPROTETTRICE
No full textVengono esaminate le principali droghe vegetali ad azione vasoprotettrice con particolare riguardo ai loro componenti attivi, al loro meccanismo d'azione e alla sicurezza d'impiego
Antimicrobial investigation of semipurified fractions of Ginkgo biloba leaves
No full textA total methanolic extract of Ginkgo biloba leaves was fractionated by solvent partition using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). The antimicrobial activity of the three fractions was evaluated using a number of Gram-positive and -negative bacteria and yeasts. The apolar fraction A appeared to be the most interesting because of its activity against several microorganisms; this fraction was further separated by high performance liquid chromatography, and shown to contain substances with strong inhibitory activity against Enterococcus faecalis 31, different from the major known chemical components of G. biloba leaves. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved
The antimutagenic activity of Lavandula angustifolia (lavender) essential oil in the bacterial reverse mutation assay
No full textEssential oils from Melaleuca alternifolia (tea-tree oil) and Lavandula angustifolia (lavender oil) are commonly used to treat minor health problems. Tea-tree oil possesses broad-spectrum antimicrobial activity, and is increasingly used for skin problems. Lavender oil, traditionally used as an antiseptic agent, is now predominantly used as a relaxant, carminative, and sedative in aromatherapy. Despite their growing use no data are available on their mutagenic potential. In this study, after determining the chemical composition of tea-tree oil and lavender oil, by gas-chromatography and mass spectrometry, we investigated their mutagenic and antimutagenic activities by the bacterial reverse mutation assay in Salmonella typhimurium TA98 and TA100 strains and in Escherichia coli WP2 uvrA strain, with and without an extrinsic metabolic activation system. Neither essential oil had mutagenic activity on the two tested Salmonella strains or on E. coli, with or without the metabolic activation system. Conversely, lavender oil exerted strong antimutagenic activity, reducing mutant colonies in the TA98 strain exposed to the direct mutagen 2-nitrofluorene. Antimutagenicity was concentration-dependent: the maximal concentration (0.80 mg/plate) reduced the number of histidine-independent revertant colonies by 66.4%. Lavender oil (0.80 mg/plate) also showed moderate antimutagenicity against the TA98 strain exposed to the direct mutagen 1-nitropyrene. Its antimutagenic property makes lavender oil a promising candidate for new applications in human healthcare. (c) 2005 Elsevier Ltd. All rights reserved
IN VITRO ACTIVITY OF TEA TREE OIL AGAINST CANDIDA ALBICANS MYCELIAL CONVERSION AND AGAINST OTHER PATHOGENIC FUNGI
No full textThe antifungal activity of Melaleuca alternifolia Maiden essential oil against some yeasts and dermatophytes is reported. The essential oil inhibited the conversion of C. albicans from yeast to the mycelial form at a concentration of 0.16% (v/v). The MICs ranged from 0.12% to 0.50% (v/v) for yeasts and 0.12% to 1% (v/v) for dermatophytes; the cytocidal activity was generally expressed at the same concentration. The results suggest that essential oil may be suitable for topical use in the treatment of fungal mucosal and cutaneous infection
Kinetics of lipase-catalyzed esterifications in SCCO2
No full textThe present communication reports the recent results and some general observations on parameters which enhance the reactivity and the enantiomeric eccess in lipase catalysed reactions in supercritical carbon dioxide. We examined, in particular, the lipase-catalysed synthesis of esters from secondary alcohols and acetic anhydride, as a function of pressure, temperature, substrates concentration and we compared the performance of the enzyme with the corresponding reactions in aliphatic and aromatic solvents
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
ANTIMICROBIAL ACTIVITY OF GINSENOSIDES
No full textThe antimicrobial activity of pure ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rg1), two chemical fractions, and the total extract of Panax ginseng root was investigated.
The results showed strong antimicrobial activity (minimum inhibitory concentration <1 μg mL−1) by some pure ginsenosides belonging to both protopanaxadiol and protopanaxatriol groups against representative Gram-positive and Gram-negative bacteria, and yeasts. Conversely, Panax ginseng chemical fractions and the total extract were inactive against the microorganisms tested.
This lack of antimicrobial activity may be due to possible antagonist effects between ginsenosides and other Panax ginseng components
Purity control of some Chinese crude herbal drugs marketed in Italy
No full textIn the present study, 10 Chinese crude herbal drugs marketed in Italy (Radix Ginseng, Radix Astragali, Rhizoma Coptidis, Rhizoma Atractylodis Macrocephalae, Radix Bupleuri, Radix Rehmanniae, Radix Paeoniae Alba, Pericarpium Citri Reticulatae, Radix Polygalae, Radix Salviae Miltiorrhizae) were analysed by the following purity assays: foreign matter, total ash, microbial and heavy metal contamination. The presence of parasites was shown in two samples; moreover, level of ash (in three samples), lead content (in one sample) and total viable aerobic count (in one sample), were higher than the limits set by the European or Italian Pharmacopoeias. Our results show some purity issues and underline the importance of the quality control
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