Effect of evening primrose extracts on oxidative stability of sunflower and rapeseed oils

A versatile method to fingerprint and compare the oxidative behaviour of lipids beyond their oxidative stability

In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stability of a lipid and to evaluate how the glyceride composition affects the entire oxidative process, to quantify the oxidation undertaken by the lipid, and numerically compare the oxidative behaviour of different lipids. The innovative aspect of the present method lies in the acquisition of a prolonged "oxygen uptake" curve (4000-10,000 min) of a lipid under oxygen and in the development of a semi-empirical fitting equation for the experimental data. This provides the induction period (oxidative stability), and allows to evaluate the rate of oxidation, the rate and the magnitude of oxidative degradation, the overall mass loss and the mass of oxygen taken by the lipid upon time. The proposed approach is used to characterize the oxidation of different edible oils with different degrees of unsaturation (linseed oil, sunflower oil, and olive oil) as well as chemically simpler compounds used in the literature to model the autoxidation of vegetable oils and lipids in general: triglycerides (glyceryl trilinolenate, glyceryl trilinoleate and glyceryl trioleate) and methyl esters (methyl linoleate and methyl linolenate). The approach proves very robust and very sensitive to changes in the sample composition.

In Vitro Biological Screening of Hartmannia rosea Extracts

The present study is focused on the assessment of the medicinal therapeutic potential extracts of H. rosea to investigate their pharmacological implications based upon science proofs. The antioxidant activity of fraction of H. rosea, namely, n-hexane (HR-1), ethyl acetate (HR-2), chloroform (HR-3), and n-butanol (HR-4), was performed by using the DPPH radical scavenging method. The cytotoxicity and enzyme inhibition assessment were also performed. All the extracts showed significant antioxidant, antibacterial, and protein kinase inhibition but none of the extracts exhibited α-amylase inhibition activity. The chloroform extract HR-3 may block a kinase receptor from binding to ATP; the lead molecule will be isolated, which may stop cancerous cell growth and demotion of cell division. It is predicted that ethyl acetate, chloroform, and n-butanol extracts of H. rosea contain polyphenolics, flavonoids, and alkaloids that are biologically effective candidates exhibiting significant cytotoxicity, antioxidant, and antimicrobial activities. They may control oxidative damage in the body tissues and act as potential antidiabetic and anticancer agents. These studies will also be helpful for future drug designing and drug development research.

Antioxidant efficacy of extracts produced from pickled and dried mustard in rapeseed and peanut oils

Antioxidant efficacy of 70% ethanol extract (EE), 70% methanol extract (ME), and water extract (WE) produced from pickled and dried mustard (Brassica juncea Coss. var. foliosa Bailey) was evaluated in rapeseed and peanut oils by using the Schaal oven method. The protective effects of aforesaid 3 extracts in stabilizing vegetable oils were tested by measuring their peroxide values, conjugated diene values, and p-anisidine values during storage of 15 d at 60 °C. Results showed that the different solvent extracts produced from pickled and dried mustard, at concentrations of 0.5% and 1.0% (w/w) in vegetable oils, could significantly (P < 0.05) lower the peroxide value, conjugated diene value, and p-anisidine value of oils during storage at 60 °C. However, the extracts at various concentrations showed a less antioxidant effect than butylated hydroxytoluene (BHT) at 200 ppm. The ultraviolet spectra of different extracts exhibited a single maximum absorbance at 268 nm. The qualitative analysis of antioxidants present in the extracts was carried out by reverse phase high performance liquid chromatography (HPLC) using a C18 column. Two phenolic compounds, gallic and protocatechuric acids, were identified. The antioxidant activity of the extracts might be attributed to the presence of these phenolics. These results indicated that the pickled and dried mustard could be used as a potential source of natural antioxidants.

PRACTICAL APPLICATION

The antioxidant activity of extracts produced from pickled and dried mustard toward rapeseed and peanut oils oxidation and the characterization of active phenolic compounds may be useful in developing natural antioxidants for vegetable oils. Moreover, the extracts could safely be used as potential antioxidant to suppress lipid oxidation in lipid-containing food products.

Actinidia macrosperma C. F. Liang (a Wild Kiwi): Preliminary Study of Its Antioxidant and Cytotoxic Activities

The antioxidant potential of Actinidia macrosperma C. F. Liang (Actinidiaceae) was investigated in vitro for total phenolic content, along with total antioxidant activity (TAA), 1,1-diphenyl 2-picryl hydrazyl (DPPH), and lipid peroxidation (LP). The results indicated that different polarity extracts of A. macrosperma exhibit different biological activities, which depends mainly on the presence of phenolic compounds. The antioxidant activity was in the following decreasing order: MeOH extract > EtOAc extract > aqueous extract > CHCl₃ extract > Hexane extract. Moreover, the cytotoxic activity of this plant by MTT dye assay using SMMC-7721 has been determined also. The hexane, EtOAc, and CHCl₃ extracts showed cytotoxicity in a dose-dependent manner. Methanol and aqueous extracts, however, showed weak activities in this test. And a very significant cytotoxic activity, not significantly different from the positive control of quercetin, was observed in CHCl₃ extract.

Antioxidant and antibacterial activities of Rumex japonicus HOUTT. Aerial parts

We evaluated total phenolic content, antioxidant activity, reducing power and antibacterial activity of ethanol, hexane, chloroform, ethyl acetate and aqueous extracts of aerial parts of Rumex japonicus HOUTT. The ethyl acetate extract had the highest amount of phenolic compounds. It also exhibited the highest reducing power and antioxidant activity when assayed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching and superoxide radical methods. The ethyl acetate extract possessed the strongest antibacterial activity against Bacillus subtilis, B. cereus and E. coli. GC-MS analysis indicated that ethyl acetate extract contained a variety of phenolic compounds. HPLC analysis showed that pyrogallol was the predominant phenolic compound in this extract. Thus, our study verified that the ethyl acetate extract has strong antioxidant and antibacterial activities which are correlated with its high level of phenolic compounds, particularly pyrogallol and pyrocatechin. This extract of R. japonicus aerial parts can be utilized as an effective and safe source of antioxidants.