Validated RP-HPLC Method for Quantification of Phenolic Compounds in Methanol Extracts of Aerial Parts and Roots of Thymus sipyleus and Evaluation of Antioxidant Potential

Purpose: To evaluate the total phenolic content and antioxidant potential of the methanol extracts of aerial parts and roots of Thymus sipyleus Boiss and also to determine some phenolic compounds using a newly developed and validated reversed phase high performance liquid chromatography (RP-HPLC) method.Methods: The total phenolic concentration of the extracts were determined using Folin Ciocalteu method. The antioxidative potential of the samples was evaluated using DPPH and ABTS assays. Phenolics responsible for the antioxidant activity of the plant were quantified by a newly developed and validated RP-HPLC method for the first time.Results: The total phenolic concentration of the aerial parts and roots were 215.1 ± 2.24 and 152.25 ± 2.31 mg GAE/g extracts, respectively. The extract obtained from the aerial parts reduced DPPH with a half-maximal inhibition concentration (IC50) of 0.703 ± 0.027 mg/mL, while the IC50 obtained from ABTS assay was 0.869 ± 0.066 mg/mL. IC50 values of Trolox used as standard for DPPH and ABTS radical scavenging assays were 0.0430 ± 0.0001 and 0.0420 ± 0.0001 mg/mL, respectively. The results revealed that T. sipyleus contains remarkable amounts of rosmarinic acid in the aerial parts (0.8887 ± 0.0016 g/100g dw) and in the roots (0.3454 ± 0.0006 g/100g dw) which is believed to be mostly responsible for the observed activity.Conclusion: T. sipyleus is a major potential antioxidant source for the food, pharmaceutical and cosmetic industry due to its high contents of rosmarinic acid and total phenolics.Keywords: Thymus sipyleus, Rosmarinic acid, Chlorogenic acid, Caffeic acid, Apigenin, Antioxidan

Purification and biochemical characterization of an extracellular lipase from psychrotolerant Pseudomonas fluorescens KE38

An extracellular lipase producing bacterium was isolated from a soil sample, and identified as a strain of Pseudomonas fluorescens by 16S rRNA gene sequencing. It was named Pseudomonas fluorescens KE38. KE38 showed psychrotolerant properties with an optimum growth temperature of 25 °C. The lipase enzyme secreted by KE38 was purified 41.13-fold with an overall yield of 54.99%, and a specific activity of 337.3 U/mg. The molecular mass of purified lipase was estimated to be approximately 43 kDa by SDS-PAGE. Although the lipase was active at a temperature range of 15-65 °C, it exhibited maximum activity at 45 °C, at pH 8.0. The enzyme exhibited high stability retaining 100% and 70% of its activity after an incubation period of 45 and 100 min at 45 °C and pH 8.0 respectively. It also showed a broad substrate specificity acting on p-nitrophenyl esters with C8-C18 acyl groups as substrates and was activated by Ca2+ and Ni2+ at 1 mM. While the enzyme retained its activity levels in the presence of a variety of organic solvents, DMSO and dimethylformamide enhanced this. High stability, broad substrate specificity and activity at cold temperatures in the presence of organic solvents, and metal ions make the extracellular lipase of KE38 a candidate for industrial applications.State Planning Agency of Turke

Comparative Analysis of Chemical Profile, Antioxidant, In-vitro and In-vivo Antidiabetic Activities of Juniperus foetidissima Willd. and Juniperus sabina L.

Fruit and leaves of junipers are commonly used internally as tea and pounded fruits are eaten to lower blood glucose levels in Anatolia. Thus, we aimed to evaluate antidiabetic and antioxidant potential and the chemical profile of Juniperus foetidissima Willd. and J. sabina L. in this study. In-vitro antidiabetic activities of leaf and fruit extracts were examined by their inhibitory activity on α-glucosidase and α-amylase enzymes. Then, in-vivo antidiabetic activities of leaf and fruit extracts of Juniperus species were investigated on streptozotocin-induced diabetic rats. Additionally, antioxidant activities (phosphomolybdenum, ferric-reducing antioxidant power and ABTS radical scavenging activity assays), phytochemical screening tests and high performance liquid chromatography analysis (HPLC) were done. In-vitro enzyme inhibitory effects of the extracts were supported by the results of in-vivo antidiabetic activity studies. Phytochemical screening tests indicated presence of flavonoids, tannins, terpenoids and carbohydrates in the extracts. Amentoflavone was identified as the major compound in the extracts and content of amentoflavone was determined. As a result, Juniperus extracts and its active constituents might be beneficial for diabetes and its complications

Bioanalytical LC/MS study of potential bacterial transglycosylation inhibitors

Bacterial transglycosylation is an interesting target in antibiotic drug development. An in vitro transglycosylation assay was developed and used to search for possible inhibitors of Staphylococcus aureus Penicillin Binding Protein 2-mediated transglycosylation. Since the substrate, Lipid II, has no UV-chromophore, the assay relies on LC coupled to MS for analysis of the incubation mixtures. Extracts from Thymus sipyleus, Salvia verticillata, Salvia virgata and Oolong tea were tested, as well as epigallocatechin gallate and ursolic acid, which are chemical compounds derived from plants. Matrix effects hampered Lipid II quantification in samples treated with very high concentrations of extracts. None of these extracts or isolated compounds appeared to have inhibitory activities towards the transglycosylation function of Penicillin Binding Protein 2.publisher: Elsevier articletitle: Bioanalytical LC/MS study of potential bacterial transglycosylation inhibitors journaltitle: Journal of Pharmaceutical and Biomedical Analysis articlelink: http://dx.doi.org/10.1016/j.jpba.2015.12.050 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved.status: publishe