Transformation of phenolic acids during radical neutralization.

Negative influence of reactive oxygen species on living organisms and stability of food products is the reason for significant interest in the substances exhibiting antioxidant properties. Phenolic acids are very popular among the known diet antioxidants. The paper presents the results of research on the application of chromatographic measurements for determination of antioxidant changes and products of radical neutralization reaction for the chosen phenolic acids (caffeic, ferulic, p-coumaric, protocatechuic and vanilic). The measurements were performed using the ABTS method in a long period time (8 days). The experiments have shown that the examined acids were depletion to ca 50 h but the reaction products (dimers or quinones) were converted into new compounds, observed in both methanolic and ethanolic measuring systems after a given period of time. The obtained results seem to be important in the context of living organisms because the biological activity of transformation products and their impact on human health have not been fully recognized yet. Moreover, the presented results can be interesting for both the producer and the consumer of food as generated substances may have influence on the nutritional value as well as the taste and aroma of the food in which phenolic compounds are applied. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05879-w.

Chromatographic and Biological Screening of Chosen Species of Schisandraceae Family: Schisandra chinensis, S. rubriflora, S. sphenanthera, S. henryi and Kadsura japonica.

HPLC and TLC profiling was carried out for leaf and fruit extracts of five Schisandraceae species: Schisandra chinensis, S. rubriflora, S. spehenanthera, S. henryi and Kadsura japonica. HPLC measurements confirmed presence of lignans and phenolic compounds in fruits and leaves of all tested species. The most abundant in lignans was S. chinensis fruit extract in which 15 compounds were detected (e. g.: schisandrol A, schisanhenol, γ-schisandrin, gomisin N). The effect-directed detection, i. e., TLC-direct bioautography against Bacillus subtilis, showed exceptionally high activity for S. chinensis and S. rubriflora fruit extracts. On the other hand, TLC-DB enzyme tests (α-glucosidase, lipase, tyrosinase and acetylcholinesterase (AChE) inhibition assays) showed that all fruit and leaf extracts have ability to inhibit the above-mentioned enzymes (except for the K. japonica fruit). The leaf extracts showed much stronger antioxidant activity than the fruit ones, which were assessed and compared using both TLC-direct bioautography and spectrophotometric measurements based on ABTS, DPPH and FRAP tests.

Antioxidant Properties of Selected Flavonoids in Binary Mixtures-Considerations on Myricetin, Kaempferol and Quercetin.

Flavonoids, secondary plant metabolites with many health-promoting properties, including antioxidant, are a valuable component of food products, especially functional foods. In the latter, plant extracts are commonly used, the properties of which are attributed to the characteristic main ingredients. However, in a mixture the antioxidant properties of the individual ingredients do not always show an additive effect. This paper presents and discusses the antioxidant properties of naturally occurring flavonoid aglycones and their binary mixtures. In the experiments, model systems were used that differed in the volume of the alcoholic antioxidant solution in the measuring system and its concentration in the range in which it occurs in nature. Antioxidant properties were determined by ABTS and DPPH methods. The presented data proved that the dominant resultant effect in the mixtures is antioxidant antagonism. The magnitude of the observed antagonism depends on the mutual relations of individual components, their concentrations and the method used to assess antioxidant properties. It was shown that the observed non-additive antioxidant effect of the mixture results from the formation of intramolecular hydrogen bonds between phenolic groups of the antioxidant molecule. The presented results may be useful in the context of proper design of functional foods.

A Concise Profile of Gallic Acid-From Its Natural Sources through Biological Properties and Chemical Methods of Determination.

Nature is a valuable source of anti-oxidants that have a health-promoting effect by inhibiting various undesirable changes leading to cell degradation and, consequently, potential disease ailments. One of them is gallic acid which has been used as a healing agent since ancient times. Currently, due to various beneficial properties, this compound is considered to be one of the main phenolic acids of great importance in numerous industries. It is commonly used as a substance protecting against the harmful effects of UV radiation, an astringent in cosmetic preparations, and a preservative in food products. Therefore, gallic acid is now deemed essential for both human health and industry. Increasingly better methods of its isolation and analysis are being developed, and new solutions are being sought to increase its production. This review, presenting a concise characterization of gallic acid, updates the knowledge about its various biological activities and methods used for its isolation and determination, including chromatographic and non-chromatographic methods.

Natural vs. artificial cannabinoid oils: the comparison of their antioxidant activities.

In the wide range of products containing hemp ingredients, cannabinoid oils are the most popular. They have gained popularity not only among people struggling with various health ailments, but also those who search for a neutral way of taking care of their body and mind. The antioxidant activities of cannabinoid oils differing in the type of their main cannabinoid [i.e., Cannabigerol (CBG), Cannabidiol (CBD), Δ9-Tetrahydrocannabinol (Δ9-THC), Cannabigerolic acid (CBGA), Cannabidiolic acid (CBDA) or Δ9-Tetrahydrocannabinolic acid (Δ9-THCA)] are compared and discussed in the paper. The oils with the same concentration of their main cannabinoid but prepared in different ways were applied in the experiments. Following the presented results, cannabinoid oils obtained from the plant extracts are characterized by evidently greater antioxidant activity than those prepared from pure cannabinoids. The essential difference in the antioxidant activity of the oils containing the neutral or acidic form of a given cannabinoid is observed only in the case of THC and THCA oils.

Correlation Study of Biological Activity with Quercetin and Phenolics Content in Onion Extracts.

In this study it was shown that the fungistatic and antioxidant activities of onion extracts are related to the type of liquid used as the extractant and the technique of its preparation. A change in the antioxidant properties of white and red onion extracts was demonstrated with the change of the temperature of the pressurized hot water extraction process, which can be easily related to the changes accompanying the process of thermal processing of vegetables and fruits during cooking. Owing to the experimental and mathematical approaches concerning both the main and characteristic components of onions, i.e., quercetin and phenols, respectively, with the biological activity of the extracts, it was possible to demonstrate the significant share of these compounds in the antifungal and antioxidant properties of the extracts. Considering that the research was carried out, inter alia, on onion husks, demonstrating a very high potential of biological properties of this waste material from agricultural production, the research results presented in the paper should encourage the popularization of the use of this so far underestimated raw material for the production of various functional materials.

Comparison of the antioxidant properties of serum and plasma samples as well as glutathione under environmental and pharmacological stress factors involving different classes of drugs.

We compared the antioxidant activity of serum and plasma samples of a known glutathione content with the activity of glutathione, whilst determining to what extent various stress factors might change the activity of the tested samples. Copper ions and benzene were used as examples of environmental stress factors, and xenobiotics in the form of representatives of various groups of drugs, were used as examples of pharmacological stressors at therapeutic ranges. The activity was assessed by the ABTS, ORAC, FRAP and CUPRAC methods. Glutathione content was measured by the HPLC-FD method. During the experiments, plasma samples were shown to be more resistant to oxidative stress. Moreover, the important role of environmental xenobiotics in oxidative stress was revealed, as well as the differentiated influence of pharmaceutical xenobiotics. Among all pharmaceutical xenobiotics tested, including representatives of antiarrhythmic, antiepileptic, cytostatic and mucolytic drugs, the greatest stress was shown for antiarrhythmic drugs and cytostatics.

Synergistic and antagonistic antioxidant effects in the binary cannabinoids mixtures.

From the group of nearly 120 cannabinoids identified in the hemp sativa and marijuana, CBG, CBD, THC and their acidic forms CBGA, CBDA and THCA are the most frequently studied. All these cannabinoids exhibit antioxidant activity manifested in the ability to scavenge free radicals, to prevent the oxidation process and to reduce metal ions. The paper reports and discusses the antioxidant properties of binary mixtures of the mentioned cannabinoids as regards their ability to scavenge free radicals. The paper shows that, depending on cannabinoid type in their binary mixture and their amounts ratio, an additive, synergistic and antagonistic effect of their antioxidant activity is observed. Binary mixtures of the tested cannabinoids in the full range of their molar ratios were used in the experiments. The presented results seems to be essential in terms of more and more numerous reports showing greater pharmacological effectiveness of binary cannabinoid mixtures compared to that of their individual components.

CBG, CBD, Δ9-THC, CBN, CBGA, CBDA and Δ9-THCA as antioxidant agents and their intervention abilities in antioxidant action.

Positive effect of some cannabinoids in the treatment and prophylaxis of a wide variety of oxidation-associated diseases and growing popularity of supplements containing cannabinoids, mainly cannabinoid oils (e.g. CBD oil, CBG oil), in the self-medication of humans cause a growing interest in the antioxidant properties of these compounds, especially those not showing psychotropic effects. Herein, we report the antioxidant activity of cannabigerol (CBG), cannabidiol (CBD), Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol (CBN), cannabigerolic acid (CBGA), cannabinolic acid (CBDA) and Δ9-tetrahydrocannabinolic acid (Δ9-THCA) estimated by spectrophotometric methods: ABTS, DPPH, ORAC, beta-carotene CUPRAC and FRAP. The presented data prove that all the examined cannabinoids exhibit antioxidant activity manifested in their ability to scavenge free radicals, to prevent the oxidation process and to reduce metal ions. Although the intensity of these activities is not the same for the individual cannabinoids it is comparable for all of them with that of E vitamin. As results from the research, the significance of the two types of electron sources presenting in examined cannabinoids, phenolic groups and double bonds transferring electrons, depends on the type of electron-accepting species - radicals/metal ions.