Essential oils and hydrophilic extracts from the leaves and flowers of Succisa pratensis Moench. and their biological activity.

This study was undertaken to evaluate the antioxidant activity of methanol and water extracts from Succisa pratensis Moench (Dipsacaceae) leaves and flowers as well as the chemical composition of the essential oils found in them and the antimicrobial activity of the oils and extracts thereof. The essential oils from S. pratensis leaves and flowers were analysed by the GC-MS. The total phenolic content was determined with Folin-Ciocalteu, that of flavonoids with aluminium chloride and that of phenolic acids with Arnov's reagent. The antioxidant activity was investigated by the DPPH radical scavenging assay. Antimicrobial activity was studied in vitro against G-positive and G-negative bacteria, and fungi using disc diffusion and broth microdilution methods. Eighty-six components of the leaf essential oil and 50 of the flower essential oil were identified. The main components of the leaf essential oil were 2-hexyl-1-octanol (5.76%) and heptacosane (5.53%), whereas hexadecanoic acid (16.10%), 8-octadecen-1-ol acetate (9.86%), methyl linolenate (8.58%), pentacosane (6.63%) and heptacosane (5.50%) were found in the flower essential oil. The essential oils exerted high antimicrobial activity (range: 0.11 to >3.44mg/ml) against the following bacteria: Pseudomonas aeruginosa, Staphylococcus aureus and fungi: Trichophyton mentagrophytes, Candida albicans, whereas the methanol and water extracts showed moderate or weak activity. The strongest antioxidant activity was shown by methanol extracts from S. pratensis leaves, IC50 = 0.09 mg/ml. There was a positive correlation between the total phenolic content and the antimicrobial activity, while for the antioxidant effect, it was not observed. The results suggest great antibacterial activity of the oils and high antioxidant activity of the methanol extract and may justify the application in treating infections.

Witkowska-Banaszczak E ，Długaszewska J 《-》

Evaluation of extracts and essential oil from Callistemon viminalis leaves: antibacterial and antioxidant activities, total phenolic and flavonoid contents.

To investigate antioxidant and antibacterial activities of Callistemon viminalis (C. viminalis) leaves. The essential oil of C. viminalis leaves obtained by hydro-distillation was analyzed by GC/MS. Different extracts were tested for total phenolic and flavonoid contents and in vitro antioxidant (DPPH assay) and antibacterial (agar disc diffusion and 96-well micro-plates methods) actives. Fourteen components were identified in the essential oil, representing 98.94% of the total oil. The major components were 1,8-cineole (64.53%) and α-pinene (9.69%). Leaf essential oil exhibited the highest antioxidant activity of (88.60±1.51)% comparable to gallic acid, a standard compound [(80.00±2.12)%]. Additionally, the biggest zone of inhibitions against the studied bacterial strains was observed by the essential oil when compared to the standard antibiotic (tetracycline). The crude methanol extract and ethyl acetate fraction had a significant antibacterial activity against the tested bacterial strains. It can be suggested that C. viminalis is a great potential source of antibacterial and antioxidant compounds useful for new antimicrobial drugs from the natural basis. The present study revealed that the essential oil as well as the methanol extracts and ethyl acetate fraction of C. viminalis leaves exhibited highly significant antibacterial activity against the tested bacterial strains.

Salem MZ ，Ali HM ，El-Shanhorey NA ，Abdel-Megeed A ... -  《-》

Terpene constituents of the aerial parts, phenolic content, antibacterial potential, free radical scavenging and antioxidant activity of Callistemon citrinus (Curtis) Skeels (Myrtaceae) from Eastern Cape Province of South Africa.

Larayetan RA ，Okoh OO ，Sadimenko A ，Okoh AI ... -  《BMC Complementary and Alternative Medicine》

Relationship between volatile components, antimicrobial and antioxidant properties of the essential oil, hydrosol and extracts of Citrus aurantium L. flowers.

In the Mediterranean Region, essential oil, hydrosol, and ethanol extract of C. aurantium flowers have a long history of usage in different products such as a flavoring agent and an ingredient of many traditional anti-infectious and skin care products. The present study was undertaken to compare the antimicrobial activity, antioxidant activity and phytochemical composition of essential oil (EO), hydrosol and ethanol extract of Cyprus Citrus aurantium L. flowers. The chemical composition of samples was determined by GC/MS. The total phenolic and flavonoid contents were determined by Folin-Ciocalteu colorimetric method and aluminum chloride colorimetric assay, respectively. Antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). The antimicrobial activity of the samples was determined by disc diffusion and broth microdilution methods against five foodborne pathogenic bacteria. The EO and ethanol extract showed significant antimicrobial activity against all tested pathogens which were attributed to the presence of important phytochemical classes such as polyphenols, flavonoids, alkaloids, and terpenes. The EO showed higher antimicrobial activity followed by ethanol extract with minimum inhibitory concentrations ≤1562mg/l and ≤6250mg/l, respectively, against Amoxycillin resistant Bacillus cereus and other test organisms. Significantly (p≤0.05) the higher total phenolic (81.37mg GAE/g) and flavonoid contents (20.34mg QE/g) were obtained in the ethanol extract with the higher antioxidant activity as compared to EO and hydrosol with half maximal inhibitory concentration (IC50) values of 96.07μg/ml in the DPPH and 66.50μg/ml in the H2O2 assay. A significant correlation (R2≥0.94) was found between phenolic content and IC50 values for DPPH and H2O2 assays. β-Cholesta-5,22-dien-3-ol, herboxide isomer and isochiapin-B are reported for the first time for essential oil. Citrus aurantium L. flowers have strong potential for the isolation of antimicrobial and antioxidant agents for further use in food and medicine industries as natural preservatives.

Değirmenci H ，Erkurt H 《-》

Chemical and biological characterisation of solvent extracts and essential oils from leaves and fruit of two Australian species of Pittosporum (Pittosporaceae) used in aboriginal medicinal practice.

Although no known medicinal use for Pittosporum undulatum Vent. (Pittosporaceae) has been recorded, anecdotal evidence suggests that Australian Aboriginal people used Pittosporum angustifolium Lodd., G. Lodd. & W. Lodd. topically for eczema, pruritis or to induce lactation in mothers following child-birth and internally for coughs, colds or cramps. Essential oil composition and bioactivity as well as differential solvent extract antimicrobial activity from Pittosporum angustifolium are investigated here first, to partially describe the composition of volatiles released in traditional applications of Pittosporum angustifolium for colds or as a lactagogue, and second to investigate antibacterial activity related to topical applications. Essential oils were also investigated from Pittosporum undulatum Vent., first to enhance essential oil data produced in previous studies, and second as a comparison to Pittosporum angustifolium. Essential oils were hydrodistilled from fruit and leaves of both species using a modified approach to lessen the negative (frothing) effect of saponins. This was achieved by floating pumice or pearlite obsidian over the mixture to crush the suds formed while boiling. Essential oil extracts were analysed using GC-MS, quantified using GC-FID then screened for antimicrobial activity using a micro-titre plate broth dilution assay (MIC). Using dichloromethane, methanol, hexane and H(2)O as solvents, extracts were produced from leaves and fruit of Pittosporum angustifolium and screened for antimicrobial activity and qualitative phytochemical character. Although the essential oil from leaves and fruit of Pittosporum undulatum demonstrated some component variation, the essential oil from fruits of Pittosporum angustifolium had major constituents that strongly varied according to the geographical location of collection, suggesting the existence of at least two chemotypes; one with high abundance of acetic acid decyl ester. This chemotype had high antimicrobial activity whilst the other chemotype had only moderate antimicrobial activity against the three microbial species investigated here. This result may support the occurrence of geographical specificity with regard to ethnopharmacological use. Antimicrobial activity screening of the solvent extracts from Pittosporum angustifolium revealed the leaves to be superior to fruit, with water being the most suitable extraction solvent. To the best of our knowledge, this study constitutes the first time essential oils, and solvent extracts from the fruits of Pittosporum angustifolium, have been examined employing comprehensive chemical and biological analysis. The essential oil composition presented in this paper, includes components with structural similarity as chemosemiotic compounds involved in mother-infant identification, which may have significance with regard to traditional applications as a lactagogue.

Sadgrove NJ ，Jones GL 《-》