Reactive oxygen and carbonyl species promote oxidative and carbonyl stress, and the development of diabetes, metabolic syndrome, cardiovascular diseases, and others. The traditional herb Cistus × incanus is known for its antioxidant properties; therefore, the current study aimed to assess how the chemical composition of a C. incanus water infusion corresponds with its antioxidative and antiglycative effects in vitro. The composition of infusions prepared from commercial products was analyzed with UHPLC-ESI-qTOF-MS. Total phenolics, flavonoids, and non-flavonoid polyphenols were determined. Antioxidant activity of infusions and selected polyphenols was investigated using DPPH, ABTS, and FRAP. Fluorometric measurements and methylglyoxal capture were performed to investigate the antiglycation activity. PCA and PLS-DA models were applied to explore the correlation between chemical and antioxidant results. The principal flavonoids in C. incanus were flavonols. In vitro tests revealed that a stronger antioxidant effect was demonstrated by plant material from Turkey rich in flavonoids, followed by Albania and Greece. Flavonols and ellagic acid displayed stronger antiradical and reducing power than EA-derived urolithins. Hyperoside was the most potent inhibitor of glycation. The results indicate that flavonoids are primarily responsible for rock rose antioxidant and antiglycation properties. PLS-DA modeling can be used to identify the origin of plant material with sensitivity and specificity exceeding 86%.

Cistus is a plant that has been used in natural medicine for hundreds of years; it works primarily as an antioxidant and cleansing agent. Cistus × incanus leaves or herb can be an attractive source of polyphenols and flavonoids. The official protocols of active compound analysis relies on the extraction of compounds of interest from plant matter, which makes their determination long and costly. An analysis of plant material in its native state can be performed using vibrational spectroscopy. This paper presents a comparison of Raman spectroscopy, attenuated total reflection in mid-infrared and diffuse reflectance technique in the near-infrared region for the simultaneous quantification of total polyphenols (TPC) and flavonoids (TF) content, as well as the determination of FRAP antioxidant activity of C. incanus material. Utilizing vibrational spectra and using partial least squares algorithm, TPC and TF were quantified with the RSEP_VAL errors in the 2.7–5.4% range, while FRAP antioxidant activity for validation sets was determined with relative errors ranged from 5.2 to 9.3%. For the analyzed parameters, the lowest errors of predictions were computed for models constructed using Raman data. The developed models allow for fast and precise quantification of the studied active compounds in C. incanus material without any chemical sample treatment.

Presbyopia is a global problem with an estimated 1.3 billion patients worldwide. In the area of functional food applications, dietary supplements or herbs, there are very few reports describing the positive effects of their use. In the available literature, there is a lack of studies in humans as well as on an animal model of extracts containing, simultaneously, compounds from the polyphenol group (in particular, anthocyanins) and iridoids, so we undertook a study of the effects of a preparation composed of these compounds on a condition of the organ of vision. Our previous experience on a rabbit model proved the positive effect of taking an oral extract of Cornus mas in stabilizing the intraocular pressure of the eye. The purpose of this study was to evaluate the effect of an orally administered ternary compound preparation on the status of physiological parameters of the ocular organ. The preparation contained an extract of the chokeberry Aronia melanocarpa, the honeysuckle berry Lonicera caerulea L., and the bilberry Vaccinium myrtillus (hereafter AKB) standardized for anthocyanins and iridoids, as bioactive compounds known from the literature. A randomized, double-blind, cross-over study lasting with a “wash-out” period of 17 weeks evaluated a group of 23 people over the age of 50, who were subjects with presbyopia and burdened by prolonged work in front of screen monitors. The group of volunteers was recruited from people who perform white-collar jobs on a daily basis. The effects of the test substances contained in the preparation on visual acuity for distance and near, sense of contrast for distance and near, intraocular pressure, and conjunctival lubrication, tested by Schirmer test, LIPCOF index and TBUT test, and visual field test were evaluated. Anthocyanins (including cyanidin 3-O-galactoside, delphinidin 3-O-arabinoside, cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, cyanidin 3-O-arabinoside) and iridoids (including loganin, sweroside, loganic acid) were identified as substances present in the extract obtained by HPLC-MS. The preliminary results showed that the composition of AKB applied orally does not change visual acuity in the first 6 weeks of administration. Only in the next cycle of the study was an improvement in near visual acuity observed in 92.3% of the patients. This may indicate potential to correct near vision in presbyopic patients. On the other hand, an improvement in conjunctival wetting was observed in the Schirmer test at the beginning of week 6 of administration in 80% of patients. This effect was weakened in subsequent weeks of conducting the experiment to 61.5%. The improvement in conjunctival hydration in the Schirmer test shows the potential beneficial effect of the AKB formulation in a group of patients with dry eye syndrome. This is the first study of a preparation based on natural, standardized extracts of chokeberry, honeysuckle berry, and bilberry. Preliminary studies show an improvement in near visual acuity and conjunctival hydration on the Schirmer test, but this needs to be confirmed in further studies.

Fermentation has been used for centuries to preserve food and to obtain products with new, attractive sensory characteristics. Fermented products are a source of dietary fiber, vitamins, bioactive compounds, and probiotic bacteria with health-promoting properties. This review provides a comprehensive overview of the effects of fermented fruits, vegetables, and legumes on metabolic disturbances characterizing metabolic syndrome (MetS). Furthermore, the chemical composition, microbial communities, and molecular mechanisms of action of fermented plant foods are discussed. Fermented fruits and vegetables, including table olives, caper fruits, and kimchi, contain polyphenols and probiotic bacteria, which are beneficial in terms of obesity and impaired glucose and lipid metabolism. Fermented legumes are a valuable source of bioactive peptides and isoflavone aglycones. Among fermented soybean products, natto stands out due to the presence of γ-polyglutamic acid, which improves glucose tolerance and the lipid profile, and nattokinase, an enzyme that acts as an angiotensin-converting enzyme inhibitor. Potential future studies focused on developing functional fermented foods and easy-to-use supplements based on fermented plant products are suggested.

The development of new cornelian cherry cultivars with stronger antidiabetic properties than those of previously studied Cornus mas L. extracts is essential. Accordingly, the aim of the present study was to assess the biological effects of fruit extracts derived from the ‘Uholok’ and ‘Koralovyi’ cultivars of C. mas and mix of two hybrids of C. mas × C. officinalis (‘Jerzy’ and ‘Tomasz’ cultivars) in rats with streptozotocin-induced diabetes mellitus. The quantitative and qualitative identification of bioactive substances in cornelian cherry fruits was conducted using HPLC-PDA. Fruit extracts from different cultivars were administered orally to rats with diabetes for 14 days at a dose of 20 mg per kg b.w. This resulted in a notable decrease in glucose-related parameters in the blood, proving the extracts’ effectiveness as inhibitors of α-glucosidase activity. The fruit extract from the hybrids showed the most pronounced effect among the studied extracts with regard to these indicators. In addition, the fruit extracts demonstrated a positive corrective impact on the metabolites of glycolysis (pyruvate and L-lactate) and lactate dehydrogenase activity. The extracts produced antioxidant effect in diabetic rats by reducing oxidative stress biomarkers in plasma. Extracts from fruits of the ‘Uholok’ and ‘Koralovyi’ cultivars exhibited a higher efficiency than the extracts from C. mas ‘Yantarnyi’ and ‘Flava’ cultivars. The biological effects of the fruit extract from the ‘Uholok’ cultivar are comparable to those of the ‘Podolski’ cultivar. These findings contribute to the understanding of the antidiabetic effect of the studied extracts and indicate their potential application as promising drugs.

Complementary pharmacological therapy using plant-based raw materials is necessary for normalizing the overall condition and reducing the risk of diabetic complications in type 1 diabetes. The search for natural remedies that prevent dysfunctions, particularly in blood cells, which are primarily exposed to prolonged hyperglycemia impacts, is especially important. This study aimed at evaluating diagnostically significant erythrocyte parameters in animals with streptozotocin-induced diabetes after administration of fruit extracts from Cornus mas cultivars `Uholok´ and `Koralovyi´ and Cornus mas × Cornus officinalis hybrids, for 14 days at a dose of 20 mg/kg body weight per day. The extracts were found to normalise erythrocyte parameters, including reticulocyte content in the blood, daily production of reticulocytes, erythrocyte count, haemoglobin concentrations, and mean cell haemoglobin. Oral administration of the studied extracts led to a rightward shift in the oxyhaemoglobin dissociation curves and an increase in P₅₀ values, indicating a reduction in haemoglobin affinity for oxygen to physiological levels, and caused a decrease in methaemoglobin content. Metabolites of anaerobic glycolysis, antioxidant enzyme activity, oxidative and nitrative stress biomarkers in the erythrocytes of diabetic rats decreased to control levels. The reduction in oxidative damage to erythrocytes, attributed to the strong antioxidant properties of the extracts, contributed to enhanced resistance to haemolysis and an increase in sialic acid-containing glycans that provide erythrocytes with a negative charge, reducing their aggregability. Cornelian cherry fruit extracts are promising sources of bioactive compounds for the development of potential antidiabetic medicines, while erythrocytes serve as indicators of the effectiveness of such pharmacotherapy.