RESUMEN

In recent years, there has been a strong consumer demand for food products that provide nutritional benefits to human health. Therefore, the assessment of the biological activity is considered as an important parameter for the promotion of high-quality food products. Herein, we introduce a novel methodology comprising a complete set of in vitro cell-free screening techniques for the evaluation of the bioactivity of various food products on the basis of their antioxidant capacity. These assays examine the free radical scavenging activities, the reducing properties, and the protective ability against oxidative damage to biomolecules. The adoption of the proposed battery of antioxidant assays is anticipated to contribute to the holistic characterization of the bioactivity of the food product under examination. Consumer motivations and expectations with respect to nutritious food products with bio-functional properties drive the global food market toward food certification. Therefore, the development and application of scientific methodologies that examine the quality characteristics of food products could increase consumers' trust and promote their beneficial properties for human health.

Asunto(s)

RESUMEN

Honey is a natural product derived from the insect Apis mellifera. Approximately 200 different compounds are included, making it a complex mixture with antimicrobial, antioxidant, and antidiabetic activity. Flavonoids and phenolic acids contained in honey are associated with its antioxidant capacity via mechanisms such as hydrogen donation and metallic ion chelation, although the exact antioxidant mechanism remains unknown. The aim of the present study was to: i) Estimate the antioxidant activity of a natural honey-based gel, commercially available under the trade name of 'Bear Strength honey gel' and to ii) assess the physiological and redox adjustments obtained after its consumption in healthy adult participants. For this purpose, 20 healthy participants (10 men and 10 women) included in their habitual diet 70 g of the honey-based gel for 14 days in a row. Pre- and post-consumption, physiological [weight, height, body mass index, body fat, waist-to-hip ratio, resting heart rate and blood pressure (BP)] and hematological (complete blood count) data were evaluated, along with the levels of five redox biomarkers: Glutathione (GSH), catalase (CAT), total antioxidant capacity (TAC), protein carbonyls (PCARBS) and thiobarbituric reactive substances (TBARS). The results revealed that the honey-based gel decreased the diastolic and mean arterial BP, especially in women, without affecting the rest of the physiological and hematological variables. Regarding the changes observed in antioxidant status variables, GSH was increased both in the total and women's group, while TAC was increased in all groups post-consumption. No changes were detected in the levels of CAT. Regarding oxidative stress, a decrease in the levels of TBARS in the total and women's group, was observed. PCARBS levels were decreased post-consumption only in the women's group. In conclusion, the present study demonstrated the potential positive effects of a honey-based gel on BP and redox status of healthy adults in a sex-specific manner.

RESUMEN

Honey is a complex mixture, containing ~180 compounds, produced by the Apis melifera bees, with promising antimicrobial and antioxidant properties. Nevertheless, the mechanisms through which honey exerts its effects remain under investigation. Plant antioxidants are found in honey and other bee products exhibiting a high bioactivity and molecular diversity. The aim of the present study was to estimate the antioxidant capacity of honey collected from areas in Greece by small­scale producers by i) using in vitro cell free assays; and ii) by investigating the effects of honey varieties on the redox status of a liver cancer cell line (HepG2) using non­cytotoxic concentrations. The findings of the present study will allow for the identification of Greek honeys with promising antioxidant capacity. For this purpose, six types of honey with various floral origins were examined in cell­free assays followed by cell­based techniques using flow cytometric analysis and redox biomarker level determination in order to evaluate the potential alterations in the intracellular redox system. The results indicated various mechanisms of action that are dependent on the honey type, concentration dependency and high antioxidant capacity. The extended findings from the literature confirm the ability of raw honey to influence the redox status of HepG2 cells. Nevertheless additional investigations are required to elucidate their mechanisms of action in cell line models.

Asunto(s)

RESUMEN

Wine is an alcoholic beverage of complex composition obtained through the fermentation of grape must. The consumption of wine has already been associated with a multitude of beneficial effects due to its high polyphenolic content. In this study, four Greek emblematic wines from two red (i.e., Xinomavro and Agiorgitiko) and two white (i.e., Assyrtiko and Malagouzia) varieties were analyzed for the estimation of their antioxidant profiles. To address this question, we assessed their ability to scavenge both synthetic and endogenous free radicals, such as DPPH•, ABTS+•, OH•, O2-, their potential reducing power, and their antimutagenic and antigenotoxic properties. All varieties exhibited potent antioxidant activity, as indicated by the results of methods above, with the red wines appearing more effective than the white ones regarding antioxidant capacity. Our small-scale study is the first to reveal that these wine varieties may have the ability to scavenge the most reactive endogenous radicals. In the future, this finding must be accompanied by larger studies to fill a knowledge gap in the scientific literature concerning a holistic approach of the in vitro antioxidant action of plant polyphenolic compounds. Conclusively, we believe that wines possess high bioactivity that allow them to settle in the industry of food additives and medicinal products.

RESUMEN

There is increasing evidence that the excessive generation of free radicals in the human body plays a major role in the pathophysiology and development of various diseases, closely associated with oxidative damage. In this frame, the consumption of antioxidant nutrients through food or dietary supplements may prevent from the harmful effects of free radicals on human cells. This work proposes a holistic approach consisting of distinct methodologies, suitable to evaluate the antioxidant and chemoprotective activity of three novel dietary supplements, each one containing active substances with complementary properties. In the first step, this approach includes in vitro studies to evaluate the antioxidant activity of the dietary supplements by measuring the parameters of free radical scavenging capacity, of reducing power activity, as well as, their ability to protect biomolecules from oxidation. Furthermore, the evaluation of their antimutagenic and antigenotoxic effects is also presented. SubsequentlySub, the specific effects of the dietary supplements were examined in three cancer cell lines (HepG2, HeLa, MKN45), by measuring redox biomarkers such as glutathione, reactive oxygen species and thiobarbituric acid reactive substances, using flow cytometry and spectrophotometry. Our results indicate that all the dietary supplements exhibit high antioxidant, antimutagenic, antigenotoxic and lipid protective activity. The most prominent result is their capability to induce oxidative damage on cancer cells via the critical decrease of the levels of their intracellular glutathione, as well as the increase of ROS and lipid peroxidation levels after the administration of non-cytotoxic concentrations. We suggest that the proposed methodology could constitute a valuable tool for the characterization of dietary supplements based on their chemical and functional properties.

Asunto(s)

RESUMEN

In this research, a model for the estimation of antioxidant content in cherry fruits from multispectral imagery acquired from drones was developed, based on machine learning methods. For two consecutive cultivation years, the trees were sampled on different dates and then analysed for their fruits' radical scavenging activity (DPPH) and Folin-Ciocalteu (FCR) reducing capacity. Multispectral images from unmanned aerial vehicles were acquired on the same dates with fruit sampling. Soil samples were collected throughout the study fields at the end of the season. Topographic, hydrographic and weather data also were included in modelling. First-year data were used for model-fitting, whereas second-year data for testing. Spatial autocorrelation tests indicated unbiased sampling and, moreover, allowed restriction of modelling input parameters to a smaller group. The optimum model employs 24 input variables resulting in a 6.74 root mean square error. Provided that soil profiles and other ancillary data are known in advance of the cultivation season, capturing drone images in critical growth phases, together with contemporary weather data, can support site- and time-specific harvesting. It could also support site-specific treatments (precision farming) for improving fruit quality in the long-term, with analogous marketing perspectives.

RESUMEN

Measuring the antioxidant capacity of foods is essential, as a means of quality control to ensure that the final product reaching the consumer will be of high standards. Despite the already existing assays with which the antioxidant activity is estimated, new, faster and low cost methods are always sought. Therefore, we have developed a novel colorimeter and combined it with a slightly modified DPPH assay, thus creating a kit that can assess the antioxidant capacity of liquids (e.g., different types of coffee, beer, wine, juices) in a quite fast and low cost manner. The accuracy of the colorimeter was ensured by comparing it to a fully validated Hitachi U-1900 spectrophotometer, and a coefficient was calculated to eliminate the observed differences. In addition, a new, user friendly software was developed, in order to render the procedure as easy as possible, while allowing a central monitoring of the obtained results. Overall, a novel kit was developed, with which the antioxidant activity of liquids can be measured, firstly to ensure their quality and secondly to assess the amount of antioxidants consumed with the respective food.

Asunto(s)