The protective effects of bilberry and lingonberry extracts against UV light-induced retinal photoreceptor cell damage in vitro

The powerful antioxidant effects of plant fruits, flowers, and leaves help to improve retinal damage and support the relief of visual fatigue

With the popularization of electronic products, visual fatigue is inevitably frequent. The causes of visual fatigue are varied, but from the perspective of physiological mechanisms, it is mainly closely related to retinal function or structural damage, especially the light source from various mobile devices and office equipments nowadays, which induces oxidative stress damage in the retina and exacerbates the degree of visual fatigue, resulting in the inability to use the eyes for a long period of time, pain in the eyes and periorbital area, blurred vision, dry eyes, tearing, and other discomforts. Food ingredients derived from natural plants have greater application in relieving visual fatigue. Therefore, this paper presents a detailed compilation of six plants that are widely used for their visual fatigue-relieving function, in the hope of providing more raw material choices for the development of products with visual fatigue-relieving functions in the future.

Plant bioactive compounds alleviate photoinduced retinal damage and asthenopia: Mechanisms, synergies, and bioavailability

The retina, an important tissue of the eye, is essential in visual transmission and sustaining adequate eyesight. However, oxidative stress and inflammatory reactions can harm retinal structure and function. Recent studies have demonstrated that exposure to light can induce oxidative stress and inflammatory reactions in retinal cells, thereby facilitating the progression of retinal damage-related diseases and asthenopia. Plant bioactive compounds such as anthocyanin, curcumin, resveratrol, lutein, zeaxanthin, epigallocatechin gallate, and quercetin are effective in alleviating retinal damage and asthenopia. Their strong oxidation resistance and unique chemical structure can prevent the retina from producing reactive oxygen species and regulating eye muscle relaxation, thus alleviating retinal damage and asthenopia. Additionally, the combination of these active ingredients produces a stronger antioxidant effect. Consequently, understanding the mechanism of retinal damage caused by light and the regulation mechanism of bioactive compounds can better protect the retina and reduce asthenopia.

Remnants from the Past: From an 18th Century Manuscript to 21st Century Ethnobotany in Valle Imagna (Bergamo, Italy)

BACKGROUND

This project originated from the study of an 18th century manuscript found in Valle Imagna (Bergamo, Italy) which contains 200 plant-based medicinal remedies. A first comparison with published books concerning 20th century folk medicine in the Valley led to the designing of an ethnobotanical investigation, aimed at making a thorough comparison between past and current phytotherapy knowledge in this territory.

METHODS

The field investigation was conducted through semi-structured interviews. All data collected was entered in a database and subsequently processed. A diachronic comparison between the field results, the manuscript, and a 20th century book was then performed.

RESULTS

A total of 109 interviews were conducted and the use of 103 medicinal plants, belonging to 46 families, was noted. A decrease in number of plant taxa and uses was observed over time, with only 42 taxa and 34 uses reported in the manuscript being currently known by the people of the valley. A thorough comparison with the remedies in the manuscript highlighted similar recipes for 12 species. Specifically, the use of agrimony in Valle Imagna for the treatment of deep wounds calls back to an ancient remedy against leg ulcers based on this species.

CONCLUSIONS

The preliminary results of this study allow us to outline the partial passage through time fragments of ancient plant-based remedies once used in the investigated area.

Effects of galectin-3 protein on UVA-induced damage in retinal pigment epithelial cells

Several inflammatory molecules have been suggested as biomarkers of age-related macular degeneration (AMD). Galectin-3 (Gal-3), which has been shown to have a protective role in corneal injury by promoting epithelial cells adhesion and migration to the extracellular matrix, is also highly expressed in the retinal pigment epithelium (RPE) of patients with AMD. This study evaluated the role of Gal-3 in an in vitro model of UVA-induced RPE damage, as a proof-of-concept. ARPE-19 cells (human RPE cell line), were incubated with Gal-3 at 0.5-2.5 µg/mL concentrations prior to UVA irradiation for 15, 30, and 45 min, which resulted in accumulated doses of 2.5, 5, and 7.5 J/cm², respectively. After 24 h incubation, MTT and LDH assays, immunofluorescence, and ELISA were performed. UVA irradiation for 15, 30, and 45 min proved to reduce viability in 83%, 46%, and 11%, respectively. Based on the latter results, we chose the intermediate dose (5-J/cm²) for further analysis. Pretreatment with Gal-3 at concentrations > 1.5 µg/mL showed to increase the viability of UVA-irradiated cells (~ 75%) compared to untreated cells (64%). Increased levels of cleaved caspase 3, a marker of cell death, were detected in the ARPE cells after UVA irradiation with or without addition of exogenous Gal-3. The inhibitory effect of Gal-3 on UVA-induced cell damage was characterized by decreased ROS levels and increased p38 activation, as detected by fluorescence analysis. In conclusion, our study suggests a photoprotective effect of Gal-3 on RPE by reducing oxidative stress and increasing p38 activation.

Recent advances in food applications of phenolic-loaded micro/nanodelivery systems

The current relevance of a healthy diet in well-being has led to a surging interest in designing novel functional food products enriched by biologically active molecules. As nature-inspired bioactive components, several lines of research have revealed the capability of polyphenolic compounds (phenolics) in the medical intervention of different ailments, i.e., tumors, cardiovascular and inflammatory diseases. Phenolics typically possess antioxidant and antibacterial properties and, due to their unique molecular structure, can offer superior platforms for designing functional products. They can protect food ingredients from oxidation and promote the physicochemical attributes of proteins and carbohydrate-based materials. Even though these properties contribute to the inherent benefits of bioactive phenolics as important functional ingredients in the food industry, the in vitro/in vivo instability, poor solubility, and low bioavailability are the main factors restricting their food/pharma applicability. Recent advances in the encapsulation realm are now offering efficient platforms to overcome these limitations. The application of encapsulation field may offer protection and controlled delivery of phenolics in food formulations. Here, we review recent advances in micro/nanoencapsulation of phenolics and highlight efficient carriers from this decade, which have been utilized successfully in food applications. Although further development of phenolic-containing formulations promises to design novel functional food formulations, and revolutionize the food industry, most of the strategies found in the scientific literature are not commercially applicable. Moreover, in vivo experiments are extremely crucial to corroborate the efficiency of such products.

The Effects of Blueberry Phytochemicals on Cell Models of Inflammation and Oxidative Stress

Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of proinflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidant effects of blueberry phytochemicals, discuss the results in terms of relevance to disease and health, and consider how different blueberry components modulate cellular mechanisms. The dampening effects of blueberry-derived molecules on inflammation and oxidative stress in cell models have been demonstrated through downregulation of the NF-κB pathway and reduction of reactive oxygen species (ROS) and lipid peroxidation. The modulatory effects of blueberry phytochemicals on the mitogen-activated protein kinase (MAPK) pathway and antioxidant system are not as well described, with inconsistent observations reported on immune cells and between models of endothelial, dermal, and ocular inflammation. Although anthocyanins are often reported as being the main bioactive compound in blueberries, no individual phytochemical has emerged as the primary compound when different fractions are compared; rather, an effect of whole blueberry extracts or synergy between different phenolic and nonphenolic extracts seems apparent. The major molecular mechanisms of blueberry phytochemicals are increasingly defined in cell models, but their relevance in more complex human systems needs further investigation using well-controlled clinical trials, in which systemic exposures to blueberry-associated molecules are measured concurrently with physiologic indices of inflammation and oxidative stress.

Lingonberries-General and Oral Effects on the Microbiome and Inflammation

Lingonberry (Vaccinium vitis ideae L.) is a low-bush wild plant found in the northern hemisphere. The berries are used in traditional medicine in Finland to treat oral yeast infections. General and oral effects of lingonberries on the microbiome and inflammation are reviewed. A brief introduction to oral microbiome symbiosis and dysbiosis, innate and adaptive immunity and inflammation are included, and special features in microbe/host interactions in the oral environment are considered. In vitro anticancer, antimicrobial, antioxidant, anti-inflammatory, and in vivo mouse and human studies are included, focusing on the symbiotic effect of lingonberries on oral and general health.

Lingonberry polyphenols: Potential SARS-CoV-2 inhibitors as nutraceutical tools?

Proposed pathway of the effect of lingonberry polyphenols on oral microbial (viral) load reduction and consequent beneficial local and systemic (respiratory tract) anti-inflammatory and antimicrobial/antiviral effects.

Bilberry Supplementation after Myocardial Infarction Decreases Microvesicles in Blood and Affects Endothelial Vesiculation

SCOPE

Diet rich in bilberries is considered cardioprotective, but the mechanisms of action are poorly understood. Cardiovascular disease is characterized by increased proatherogenic status and high levels of circulating microvesicles (MVs). In an open-label study patients with myocardial infarction receive an 8 week dietary supplementation with bilberry extract (BE). The effect of BE on patient MV levels and its influence on endothelial vesiculation in vitro is investigated.

METHODS AND RESULTS

MVs are captured with acoustic trapping and platelet-derived MVs (PMVs), as well as endothelial-derived MVs (EMVs) are quantified with flow cytometry. The in vitro effect of BE on endothelial extracellular vesicle (EV) release is examined using endothelial cells and calcein staining. The mechanisms of BE influence on vesiculation pathways are studied by Western blot and qRT-PCR. Supplementation with BE decreased both PMVs and EMVs. Furthermore, BE reduced endothelial EV release, Akt phosphorylation, and vesiculation-related gene transcription. It also protects the cells from P2X7 -induced EV release and increase in vesiculation-related gene expression.

CONCLUSION

BE supplementation improves the MV profile in patient blood and reduces endothelial vesiculation through several molecular mechanisms related to the P2X7 receptor. The findings provide new insight into the cardioprotective effects of bilberries.

Using Medicinal Plants in Valmalenco (Italian Alps): From Tradition to Scientific Approaches

This ethnobotanical survey was carried out in Caspoggio (Valmalenco, SO, Italy) with the purpose of investigating the traditional uses of medicinal plants. Moreover, a bibliographic research meant to validate or refute the uses, focusing on the potentially responsible compounds, was performed. Fifty-nine species, attributable to 30 families (Asteraceae, Pinaceae, Malvaceae, and Lamiaceae the most cited), were mentioned. Arnica montana, anti-inflammatory for traumas and musculoskeletal pains; Pinus mugo, expectorant; Malva sylvestris, anti-inflammatory and soothing; Achillea moschata, digestive. The compounds, responsible for the therapeutic activities, are often polyphenols and terpenoids: helenanin in A. montana, α-pinene, δ-3-carene, and limonene in P. mugo, gossypin and malvin in M. sylvestris, luteolin and apigenin in A. moschata. Scientific evidence for at least one of the traditional activities described was found for 50 species but only in 26 out of 196 works consulted, it is possible to make a comparison between investigated extracts and traditional preparations. This study is thus a stimulus to new phytochemical investigations, mimicking as much as possible the traditional preparations. This work is part of the European Interreg Italy-Switzerland B-ICE project, aimed at creating a management model for the ongoing climate change and searching for new sources of territory valorization as attractions for tourists.

Protective effects of delphinidin against H2O2-induced oxidative injuries in human retinal pigment epithelial cells

Age-related macular degeneration (AMD) is now one of the leading causes of blindness in the elderly population and oxidative stress-induced damage to retinal pigment epithelial (RPE) cells occurs as part of the pathogenesis of AMD. In the present study, we evaluated the protective effect of delphinidin (2-(3,4,5-trihydroxyphenyl) chromenylium-3,5,7-triol) against hydrogen peroxide (H₂O₂)-induced toxicity in human ARPE-19 cells and its molecular mechanism. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry demonstrated that pretreatment of ARPE-19 cells with delphinidin (25, 50, and 100 μg/ml) significantly increased cell viability and reduced the apoptosis from H₂O₂ (0.5 mM)-induced oxidative stress in a concentration-dependent manner, which was achieved by the inhibition of Bax, cytochrome c, and caspase-3 protein expression and enhancement of Bcl-2 protein. The same tendency was observed in ARPE-19 cells pre-treated with 15 mM of N-acetylcysteine (NAC) before the addition of H₂O₂. Furthermore, pre-incubation of ARPE-19 cells with delphinidin markedly inhibited the intracellular reactive oxygen species (ROS) generation and Nox1 protein expression induced by H₂O₂. Moreover, the decreased antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-peroxidase (GSH-PX) and elevated (MDA) level in H₂O₂-treated cells were reversed to the normal standard by the addition of delphinidin, which was regulated by increasing nuclear Nrf2 protein expression in ARPE-19 cells. Our results suggest that delphinidin effectively protects human ARPE-19 cells from H₂O₂-induced oxidative damage via anti-apoptotic and antioxidant effects.

Inhibitory Effects of Lingonberry Extract on Oral Streptococcal Biofilm Formation and Bioactivity

Phenolic compounds in fruits such as cranberries have been shown to promote a number of biological activities. The purpose of this study was to investigate the effects of polyphenolic compound-containing lingonberry extract on oral streptococci and compare them with the known anti-cariogenic activity of cranberries. Water-soluble and polyphenol-rich fractions (Fractions I and II, respectively) were isolated from cranberries and lingonberries. The effects of those fractions on the biofilm formation ability and bioactivity of Streptococcus mutans MT8148R, Streptococcus sobrinus 6715, and Streptococcus sanguinis ATCC 10556 were then evaluated. Cranberry or lingonberry Fraction II (at 0.5-1 mg/ml) significantly reduced biofilm formation by S. mutans, S. sobrinus, and S. sanguinis. In contrast, cranberry or lingonberry Fraction I (at 0.5-2 mg/ml) increased biofilm formation by S. mutans and S. sobrinus, but not by S. sanguinis. Fractions I and II (at 1-2 mg/ml) also reduced the bioactivity of S. mutans, while Fraction II (at 0.5 mg/ml) enhanced the bioactivity of all tested strains. The results revealed that lingonberries contained a larger amount of polyphenol than cranberries and that they showed almost the same level of activity against the biofilm formation ability and bioactivity of oral streptococci. This indicates that polyphenol-rich lingonberry fraction offers a promising natural food derivative for prevention of dental caries.

Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L.) Seed against Visible Light-Induced Retinal Degeneration in Vivo

Dietary proanthocyanidins (PACs) as health-protective agents have become an important area of human nutrition research because of their potent bioactivities. We investigated the retinoprotective effects of PACs from sea buckthorn (Hippophae rhamnoides L.) seed against visible light-induced retinal degeneration in vivo. Pigmented rabbits were orally administered sea buckthorn seed PACs (50 and 100 mg/kg/day) for 14 consecutive days of pre-illumination and seven consecutive days of post-illumination. Retinal function was quantified via electroretinography 7 days after light exposure. Retinal damage was evaluated by measuring the thickness of the full-thickness retina and outer nuclear layer 7 days after light exposure. Sea buckthorn seed PACs significantly attenuated the destruction of electroretinograms and maintained the retinal structure. Increased retinal photooxidative damage was expressed by the depletion of glutathione peroxidase and catalase activities, the decrease of total antioxidant capacity level and the increase of malondialdehyde level. Light exposure induced a significant increase of inflammatory cytokines (IL-1β, TNF-α and IL-6) and angiogenesis (VEGF) levels in retina. Light exposure upregulated the expression of pro-apoptotic proteins Bax and caspase-3 and downregulated the expression of anti-apoptotic protein Bcl-2. However, sea buckthorn seed PACs ameliorated these changes induced by light exposure. Sea buckthorn seed PACs mediated the protective effect against light-induced retinal degeneration via antioxidant, anti-inflammatory and antiapoptotic mechanisms.

Analysis and characterization of anthocyanins and carotenoids in Japanese blue tomato

Tomato (Solanum lycopersicum) is rich in anthocyanins, which are polyphenolic pigments. This study aimed to analyze and characterize the anthocyanin composition in cultivated blue tomato in Japan. The extracts of peel, seed, and pulp of tomatoes were purified following which anthocyanins and lycopene contents were analyzed using high-performance liquid chromatography and electrospray ionization mass spectrometry. Eleven types of anthocyanins were identified, including delphinidin, petunidin, and malvidin. Further, the antioxidant activity of anthocyanins was evaluated using 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt radical quenching assays and electron spin resonance. “Blue tomato” extracts exert antioxidant activity. Thus, we showed that petunidin was present in the “blue tomato” peel while lycopene was present in the peel and pulp. Additionally, the blue tomato peel extract was found to significantly inhibit H2O2-induced cell death in vitro. This is the first study on cell protective effects of Japanese blue tomato extract and petunidin in murine photoreceptor cells.

Protective Effect of Total Flavones from Hippophae rhamnoides L. against Visible Light-Induced Retinal Degeneration in Pigmented Rabbits

Sea buckthorn (Hippophae rhamnoides L.) flavones have been used as candidate functional food ingredients because of their bioactivities, such as treating cardiovascular disorders, lowering plasma cholesterol level, and regulating immune function. However, the protective effects of sea buckthorn flavones against retinal degeneration remain unclear to date. This study investigated the protective effects of total flavones from H. rhamnoides (TFH) against visible light-induced retinal damage and explored the related mechanisms in pigmented rabbits. Rabbits were treated with TFH (250 and 500 mg/kg) for 2 weeks pre-illumination and 1 week post-illumination until sacrifice. Retinal function was quantified by performing electroretinography 1 day before and 1, 3, and 7 days after light exposure (18000 lx for 2 h). Retinal degeneration was evaluated by measuring the thickness of the outer nuclear layer (ONL) and performing the TUNEL assay 7 days after light exposure. Enzyme-linked immunosorbent assay, Western blot analysis, and immunohistochemistry were used to explore the antioxidant, anti-inflammatory, and anti-apoptotic mechanisms of TFH during visible light-induced retinal degeneration. Light exposure produced a degenerative effect primarily on the ONL, inner nuclear layer (INL), and ganglion cell layer (GCL). TFH significantly attenuated the destruction of electroretinograms caused by light damage, maintained ONL thickness, and decreased the number of TUNEL-positive cells in the INL and GCL. TFH ameliorated the retinal oxidative stress (GSH-Px, CAT, T-AOC, and MDA), inflammation (IL-1β and IL-6), angiogenesis (VEGF), and apoptosis (Bax, Bcl2, and caspase-3) induced by light exposure. Therefore, TFH exhibited protective effects against light-induced retinal degeneration by increasing the antioxidant defense mechanisms, suppressing pro-inflammatory and angiogenic cytokines, and inhibiting retinal cell apoptosis.

The protective effects of berry-derived anthocyanins against visible light-induced damage in human retinal pigment epithelial cells

BACKGROUND

Studies have shown that anthocyanins (ACNs) in berries contribute to eye health. However, information on the relationship between the chemical structures and visual functions of ACNs is scarce. This study investigated the protection effects of ACNs with different structures against visible light-induced damage in human retinal pigment epithelial (RPE) cells.

RESULTS

Four ACNs with different aglycones, namely, pelargonidin-3-glucoside (Pg-3-glu), cyanidin-3-glucoside (Cy-3-glu), delphinidin-3-glucoside, and malvidin-3-glucoside (Mv-3-glu), were isolated from three berries (blueberry, blackberry and strawberry). Of these ACNs, Cy-3-glu exhibited the highest reactive oxygen species inhibitory capacity in RPE cells, with 40 µg mL(-1) Cy-3-glu showing a ROS clearance of 57.5% ± 4.2%. The expression of vascular endothelial growth factor levels were significantly (P < 0.05) down-regulated by Cy-3-glu and Mv-3-glu in a visible light-induced damage RPE cell model. Cy-3-glu and Pg-3-glu treatments significantly (P < 0.05) inhibited the increase in β-galactosidase during the RPE cell ageing caused by visible light exposure.

CONCLUSION

Our findings suggest that the biological properties of different ACNs significantly vary. Cy-3-glu, which contains an ortho hydroxyl group in its B ring, possibly exerts multiple protective effects (antioxidant, anti-angiogenic and anti-ageing) in RPE cells. Therefore, Cy-3-glu may prove useful as a prophylactic health food for the prevention of retinal diseases.

Radioprotective and antioxidant effect of resveratrol in hippocampus by activating Sirt1

Reactive oxygen species can lead to functional alterations in lipids, proteins, and nucleic acids, and an accumulation of ROS (Reactive oxygen species) is considered to be one factor that contributes to neurodegenerative changes. An increase in ROS production occurs following irradiation. Neuronal tissue is susceptible to oxidative stress because of its high oxygen consumption and modest antioxidant defenses. As a polyphenolic compound, resveratrol is frequently used as an activator of Sirt1 (Sirtuin 1). The present study was designed to explore the radioprotective and antioxidant effect of resveratrol on Sirt1 expression and activity induced by radiation and to provide a new target for the development of radiation protection drugs. Our results demonstrate that resveratrol inhibits apoptosis induced by radiation via the activation of Sirt1. We demonstrated an increase in Sirt1 mRNA that was present on 21 days of resveratrol treatment following irradiation in a concentration-dependent manner. Such mRNA increase was accompanied by an increase of Sirt1 protein and activity. Resveratrol effectively antagonized oxidation induced by irradiation, supporting its cellular ROS-scavenging effect. These results provide evidence that the mitochondrial protection and the antioxidant effect of resveratrol contribute to metabolic activity. These data suggest that Sirt1 may play an important role to protect neurons from oxidative stress.

Protective effects of bilberry and lingonberry extracts against blue light-emitting diode light-induced retinal photoreceptor cell damage in vitro

Background

Blue light is a high-energy or short-wavelength visible light, which induces retinal diseases such as age-related macular degeneration and retinitis pigmentosa. Bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea) contain high amounts of polyphenols (anthocyanins, resveratrol, and proanthocyanidins) and thus confer health benefits. This study aimed to determine the protective effects and mechanism of action of bilberry extract (B-ext) and lingonberry extract (L-ext) and their active components against blue light-emitting diode (LED) light-induced retinal photoreceptor cell damage.

Methods

Cultured murine photoreceptor (661 W) cells were exposed to blue LED light following treatment with B-ext, L-ext, or their constituents (cyanidin, delphinidin, malvidin, trans-resveratrol, and procyanidin B2). 661 W cell viability was assessed using a tetrazolium salt (WST-8) assay and Hoechst 33342 nuclear staining, and intracellular reactive oxygen species (ROS) production was determined using CM-H₂DCFDA after blue LED light exposure. Activation of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor-kappa B (NF-κB), and LC3, an ubiquitin-like protein that is necessary for the formation of autophagosomes, were analyzed using Western blotting. Caspase-3/7 activation caused by blue LED light exposure in 661 W cells was determined using a caspase-3/7 assay kit.

Results

B-ext, L-ext, NAC, and their active components improved the viability of 661 W cells and inhibited the generation of intracellular ROS induced by blue LED light irradiation. Furthermore, B-ext and L-ext inhibited the activation of p38 MAPK and NF-κB induced by blue LED light exposure. Finally, B-ext, L-ext, and NAC inhibited caspase-3/7 activation and autophagy.

Conclusions

These findings suggest that B-ext and L-ext containing high amounts of polyphenols exert protective effects against blue LED light-induced retinal photoreceptor cell damage mainly through inhibition of ROS production and activation of pro-apoptotic proteins.