Blackthorn fruit peel polyphenol extracts and photodynamic effect under blue light against Listeria monocytogenes.

Photodynamic inactivation is an emerging antimicrobial treatment that can be enhanced by employing exogenous photosensitizers to eradicate foodborne pathogens. This study investigated a novel combinatory strategy to eradicate Listeria monocytogenes using blackthorn fruit peel (BFP) and blue light (BL). Extracts of BFP were characterized in terms of polyphenolic content, individual constituents, and antioxidant and antimicrobial activity. The concentration of phenolic compounds and antioxidant activity were both found to be determinants of antimicrobial activity. It was further speculated that flavonols, predominantly quercetin and rutin, were responsible for the activity of BFP against L. monocytogenes. A combination of BFP and BL resulted in a rapid inactivation of the pathogen by up to 4 log CFU/mL at 58.5 J/cm2, corresponding to 15 min BL illumination. Flow cytometry analysis revealed that the bacterial cells lost activity and suffered extensive membrane damage, exceeding 90% of the population. After photosensitizing L. monocytogenes with the BFP constituents quercetin and rutin, a 1.3-log reduction was observed. When applied together, these compounds could inflict the same damaging effect on cells as they did individually when effects were added. Therefore, the results indicate that BFP represents a natural source of (pro-)photosensitizers, which act additively to create inactivation effects. This study may help identify more effective plant-based photosensitizers to control L. monocytogenes in food-related applications.

Effect of blue light emitting diode therapy on recurrent vulvovaginal candidiasis: A randomized assessor-blinded controlled trial.

OBJECTIVE: Vulvovaginal Candidiasis (VVC) is a prevalent genital infection in women of reproductive age and requires effective non-drug therapies. Therefore, this study aimed to investigate the effect of blue light emitting diode (LED) therapy as an alternative treatment for recurrent VVC due to its proven antimicrobial properties. The safety and non-invasiveness of LED therapy make it a promising option for sensitive tissue applications. MATERIALS AND METHODS: This randomized controlled trial recruited 60 women with culture-confirmed VVC. Participants were randomly allocated to two groups. Group A (control group) received standard antifungal treatment with Gynoconazol 0.8% vaginal cream for three consecutive nights (n = 30). Group B (study group) received the same antifungal treatment plus two 60-min sessions of blue LED therapy directed at the vagina and vulva, with the sessions separated by two days (n = 30). Candida count (via CHROMagar™ Candida) and vaginal pH (via AD110-AD111 m) were assessed at baseline and one week after initiating treatment. RESULTS: Post-treatment, group (B) demonstrated a significantly greater reduction in Candida count compared to group (A) (mean difference (MD) 8.267; 95% Confidence Interval (CI) 6.723-9.811; p = 0.0001). However, there was no statistically significant difference in vaginal pH between the groups (MD -0.03; 95% CI -0.244-0.178; p = 0.749). CONCLUSION: Blue LED therapy effectively reduces Candida count in women with recurrent VVC without adversely affecting the vaginal pH, highlighting its safety and efficacy as a treatment modality.

Exploration of the Graphene Quantum Dots-Blue Light Combination: A Promising Treatment against Bacterial Infection.

Graphene Quantum Dots (GQDs) have shown the potential for antimicrobial photodynamic treatment, due to their particular physicochemical properties. Here, we investigated the activity of three differently functionalized GQDs-Blue Luminescent GQDs (L-GQDs), Aminated GQDs (NH2-GQDs), and Carboxylated GQDs (COOH-GQDs)-against E. coli. GQDs were administrated to bacterial suspensions that were treated with blue light. Antibacterial activity was evaluated by measuring colony forming units (CFUs) and metabolic activities, as well as reactive oxygen species stimulation (ROS). GQD cytotoxicity was then assessed on human colorectal adenocarcinoma cells (Caco-2), before setting in an in vitro infection model. Each GQD exhibits antibacterial activity inducing ROS and impairing bacterial metabolism without significantly affecting cell morphology. GQD activity was dependent on time of exposure to blue light. Finally, GQDs were able to reduce E. coli burden in infected Caco-2 cells, acting not only in the extracellular milieu but perturbating the eukaryotic cell membrane, enhancing antibiotic internalization. Our findings demonstrate that GQDs combined with blue light stimulation, due to photodynamic properties, have a promising antibacterial activity against E. coli. Nevertheless, we explored their action mechanism and toxicity on epithelial cells, fixing and standardizing these infection models.

Blue light photobiomodulation induced osteosarcoma cell death by facilitating ferroptosis and eliciting an incomplete tumor cell stress response.

To investigate the potential of blue light photobiomodulation (PBM) in inducing ferroptosis, a novel form of regulated cell death, in OS cells, considering its known effectiveness in various cancer models. In this investigation, we exposed human OS cell lines, HOS and MG63, to different wavelengths (420, 460 and 480 nm) of blue light at varying irradiances, and examined cellular responses such as viability, apoptosis, levels of reactive oxygen species (ROS), and mitochondrial membrane potential (MMP). Transcriptome sequencing was employed to unravel the molecular mechanisms underlying blue light-induced effects, with validation via quantitative real-time PCR (qRT-PCR). Our findings revealed a wavelength- and time-dependent decrease in cell viability, accompanied by increased apoptosis and oxidative stress. Transcriptomic analysis identified differential expression of genes associated with ferroptosis, oxidative stress, and iron metabolism, further validated by qRT-PCR. These results implicated ferroptosis as a significant mechanism in the blue light-induced death of OS cells, potentially mediated by ROS generation and disruption of iron homeostasis. Also, An incomplete stress response was observed in MG63 cells induced by blue light exposure. Hence, blue light PBM holds promise as a therapeutic approach in OS clinical investigations; however, additional exploration of its underlying mechanisms remains imperative.

Modified Hybrid Hydroxyapatite-Silver Nanoparticles Activated via a Blue Light Source in Various Concentrations in Two-Step Self-Etch Adhesive to Caries-Affected Primary Dentin.

Aims: To evaluate hydroxyapatite-silver (HA-Ag) hybrid nanoparticles (NPs), as an antibacterial agent when integrated in self-etch (SE) adhesive. Blue light activated HA-Ag hybrid NP incorporation on mechanical properties, degree of conversion (DC), and microtensile bond strength (µTBS). Method: Eighty primary molar teeth have carious lesions reaching the dentin but not involving the pulp. The infected dentin was removed and carious-affected dentin (CAD) was preserved. Forty samples were inoculated with Streptococcus mutans. All primary teeth (n = 80) were allocated into four groups based on the incorporation of HA-Ag hybrid NPs in different concentrations (0%, 1%, 5%, and 10%). Group 1: 0% HA-Ag hybrid NPs + Clearfil SE bond primer, group 2: 1% HA-Ag hybrid NPs + Clearfil SE bond primer, group 3: 5 wt% HA-Ag NPs + Clearfil SE bond primer, and group 4: 10 wt% HA-Ag NPs + Clearfil SE bond primer. The survival rate assessment of S. mutans was conducted on 40 inoculated samples. On the remaining primary teeth (n = 40), Clearfil SE bonding agent was applied uniformly via a blue light source. The composite buildup was performed on the samples and µTBS and failure analysis assessed. Fourier transform infrared spectroscopy was performed to assess DC. Survival rates of S. mutans and µTBS among the tested groups were compared using ANOVA and Tukey post hoc analysis. Results: 10 wt % HA-Ag NPs + Clearfil SE bond primer exhibited the highest level of antibacterial efficacy (0.14 ± 0.02 CFU/mL) against S. mutans. The highest µTBS (18.38 ± 0.78 MPa) at the composite/CAD interface was in group 2 (1 wt % HA-Ag NPs + Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source). The highest DC was observed in the control group with Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source. Conclusion: 1 wt% HA-Ag hybrid NPs showed enhanced antibacterial effectiveness, DC, and bond strength of the SE adhesive to the primary CAD.

The role of the SIRT1/NF-κB/NLRP3 pathway in the pyroptosis of lens epithelial cells under shortwave blue light radiation.

Cataracts are the world's number one blinding eye disease. Cataracts can only be effectively treated surgically, although there is a chance of surgical complications. One of the pathogenic processes of cataracts is oxidative stress, which closely correlated with pyroptosis. SIRT1 is essential for the regulation of pyroptosis. Nevertheless, the role of SIRT1 in formation of cataracts is unclear. In this work, we developed an in vitro model of shortwave blue light (SWBL)-induced scotomization in human lens epithelial cells (HLECs) and an in vivo model of SWBL-induced cataracts in rats. The study aimed to understand how the SIRT1/NF-κB/NLRP3 pathway functions. Additionally, the evaluation included cell death and the release of lactate dehydrogenase (LDH), a cytotoxicity marker, from injured cells. First, we discovered that SWBL exposure resulted in lens clouding in Sprague- Dawley (SD) rats and that the degree of clouding was positively linked to the duration of irradiation. Second, we discovered that SIRT1 exhibited antioxidant properties and was connected to the NF-κB/NLRP3 pathway. SWBL irradiation inhibited SIRT1 expression, exacerbated oxidative stress, and promoted nuclear translocation of NF-κB and the activation of the NLRP3 inflammasome, which caused LEC pyroptosis and ultimately led to cataract formation. Transient transfection to increase the expression of SIRT1 decreased the protein expression levels of NF-κB, NLRP3, caspase-1, and GSDMD, inhibited HLEC pyroptosis, and reduced the release of LDH, providing a potential method for cataract prevention and treatment.

Synergistic Effect of Doxorubicin and Blue Light Irradiation on the Antitumor Treatment of HepG2 Cells in Liver Cancer.

Doxorubicin (DOX) has been an effective antitumor agent for human liver cancer cells; however, an overdose might lead to major side effects appearing in clinical applications. In this work, we present a strategy of combining DOX and blue light (BL) irradiation for the antitumor treatment of HepG2 cells (one typical human liver cancer cell line). It is demonstrated that synergetic DOX and BL can significantly reduce cell proliferation and increase the apoptotic rate of HepG2 cells in comparison to individual DOX treatment. The additional BL irradiation is further helpful for enhancing the inhibition of cell migration and invasion. Analyses of reactive oxygen species (ROS) level and Western blotting reveal that the strategy results in more ROS accumulation, mitochondrial damage, and the upregulation of proapoptotic protein (Bcl-2) and downregulation of antiapoptotic protein (Bax). In addition to the improved therapeutic effect, the non-contact BL irradiation is greatly helpful for reducing the dosage of DOX, and subsequently reduces the side effects caused by the DOX drug. These findings offer a novel perspective for the therapeutic approach toward liver cancer with high efficiency and reduced side effects.

Effect of Green Light Replacing Some Red and Blue Light on Cucumis melo under Drought Stress.

Light quality not only directly affects the photosynthesis of green plants but also plays an important role in regulating the development and movement of leaf stomata, which is one of the key links for plants to be able to carry out normal growth and photosynthesis. By sensing changes in the light environment, plants actively regulate the expansion pressure of defense cells to change stomatal morphology and regulate the rate of CO2 and water vapor exchange inside and outside the leaf. In this study, Cucumis melo was used as a test material to investigate the mitigation effect of different red, blue, and green light treatments on short-term drought and to analyze its drought-resistant mechanism through transcriptome and metabolome analysis, so as to provide theoretical references for the regulation of stomata in the light environment to improve the water use efficiency. The results of the experiment showed that after 9 days of drought treatment, increasing the percentage of green light in the light quality significantly increased the plant height and fresh weight of the treatment compared to the control (no green light added). The addition of green light resulted in a decrease in leaf stomatal conductance and a decrease in reactive oxygen species (ROS) content, malondialdehyde MDA content, and electrolyte osmolality in the leaves of melon seedlings. It indicated that the addition of green light promoted drought tolerance in melon seedlings. Transcriptome and metabolome measurements of the control group (CK) and the addition of green light treatment (T3) showed that the addition of green light treatment not only effectively regulated the synthesis of abscisic acid (ABA) but also significantly regulated the hormonal pathway in the hormones such as jasmonic acid (JA) and salicylic acid (SA). This study provides a new idea to improve plant drought resistance through light quality regulation.

LOV1 protein of Pseudomonas cichorii JBC1 modulates its virulence and lifestyles in response to blue light.

Bacteria perceive light signals via photoreceptors and modulate many physiological and genetic processes. The impacts played by light, oxygen, or voltage (LOV) and blue light (BL) photosensory proteins on the virulence-related traits of plant bacterial pathogens are diverse and complex. In this study, we identified LOV protein (Pc-LOV1) from Pseudomonas cichorii JBC1 (PcJBC1) and characterized its function using LOV1-deficient mutant (JBC1Δlov1). In the dark state, the recombinant Pc-LOV1 protein showed an absorption band in UV-A region with a double peak at 340 nm and 365 nm, and within the blue-region, it exhibited a main absorption at 448 nm along with two shoulder peaks at 425 nm and 475 nm, which is a typical feature of oxidized flavin within LOV domain. The adduct-state lifetime (τrec) of Pc-LOV1 was 67.03 ± 4.34 min at 25 °C. BL negatively influenced the virulence of PcJBC1 and the virulence of JBC1Δlov1 increased irrespective of BL, indicating that Pc-LOV1 negatively regulates PcJBC1 virulence. Pc-LOV1 and BL positively regulated traits relevant to colonization on plant surface, such as adhesion to the plant tissue and biofilm formation. In contrast, swarming motility, exopolysaccharide production, and siderophore synthesis were negatively controlled. Gene expression supported the modulation of bacterial features by Pc-LOV1. Overall, our results suggest that the LOV photosensory system plays crucial roles in the adaptive responses and virulence of the bacterial pathogen PcJBC1. The roles of other photoreceptors, sensing of other wavelengths, and signal networking require further investigation.

Protective effect and mechanism of Lycium ruthenicum Murray anthocyanins against retinal damage induced by blue light exposure.

Lycium ruthenicum Murray (LR) is a medicine and edible plant in Northwest China, and L. ruthenicum Murray anthocyanins (LRA) are green antioxidants with various pharmacological activities, such as antioxidant and anti-inflammatory activities. However, the protective effect and mechanism of LRA against retinal damage induced by blue light exposure are poorly understood. This study explored the protective effects and potential mechanisms of LRA on retinal damage induced by blue light exposure in vitro and in vivo. The results showed that LRA could ameliorate oxidative stress injury by activating the antioxidant stress nuclear factor-related factor 2 pathway, promoting the expression of phase II detoxification enzymes (HO-1, NQO1) and endogenous antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), and reducing reactive oxygen species and malondialdehyde levels. Additionally, LRA could inhibit inflammatory response by decreasing the expression of blue light exposure-induced nuclear factor-κB (NF-κB) pathway-related proteins (NF-κB and p-IκBα), as well as interleukin (IL)-6, tumor necrosis factor-α, IL-1ß pro-inflammatory factors and pro-inflammatory chemokine VEGF, and increasing the expression of anti-inflammatory factor IL-10. Furthermore, LRA could ameliorate oxidative stress-induced apoptosis by upregulating Bcl-2 and downregulating Bax and Caspase-3 protein expression. All these results indicate that LRA can be used as an antioxidant dietary supplement for the treatment or prevention of retinal diseases.

The transcriptional changes of LrgA discriminates the responsiveness of Staphylococcus aureus towards blue light from that of photodynamic inactivation.

Antimicrobial blue light (aBL) is utilized as a new approach to inhibit the growth of Staphylococcus aureus (S. aureus). Mediated by the endogenous chromophore, aBL possesses the similar photokilling property with aPDI (antimicrobial photodynamic inactivation), however, their mechanistic discrepancies in triggering the death of staphylococcal cells are not yet understood. Here, we describe the use of a 460-nm-LED to curb the viability of S. aureus. According to the results, the bacterial survival was sharply decreased when blue light was applied, reaching a maximum of 4.11 ± 0.04 log10 units. Moreover, the membrane integrity was damaged by aBL, causing the leakage of intracellular DNA. Transcriptomic analysis indicates the divergent gene expression upon either aBL or aPDI, with pathways such as transport, DNA repair, expression regulation and porphyrin massively affected by aBL. Among the commonly regulated genes, LrgA was underpinned on account of its involvement with biofilm formation and protein transport. By comparing the wildtype with the LrgA-overexpressing (LrgA+) strain, the survival rate, membrane penetration, surface structure and biofilm formation were, to a varying degree, improved for LrgA+, which may suggest that LrgA plays essential roles in modulating the responsiveness of S. aureus. Besides, LrgA may function through regulating the expression of autolysis-related systems. Finally, LrgA overexpression did not attenuate but aggravate the impairment induced by aPDI, showcasing a distinct responsive strategy from aBL. Taken together, this study unveils a unique molecular alteration for the aBL-mediated inactivation, providing the basis of utilizing blue light to reduce the harm brought by S. aureus.

Decrease of alpha-crystallin A by miR-325-3p in retinal cells under blue light exposure.

Exposure to blue light can lead to retinal degeneration, causing adverse effects on eye health. Although the loss of retinal cells due to blue light exposure has been observed, the precise molecular mechanisms underlying this process remain poorly understood. In this study, we investigate the role of alpha-crystallin A (CRYAA) in neuro-retinal degeneration and their regulation by blue light. We observed significant apoptotic cell death in both the retina of rats and the cultured neuro-retinal cells. The expressions of Cryaa mRNA and protein were significantly downregulated in the retina exposed to blue light. We identified that miR-325-3p reduces Cryaa mRNA and protein by binding to its 3'-untranslated region. Upregulation of miR-325-3p destabilized Cryaa mRNA and suppresses CRYAA, whereas downregulation of miR-325-3p increased both expressions. Blue light-induced neuro-retinal cell death was alleviated by CRYAA overexpression. These results highlight the critical role of Cryaa mRNA and miR-325-3p molecular axis in blue light-induced retinal degeneration. Consequently, targeting CRYAA and miR-325-3p presents a potential strategy for protecting against blue light-induced retinal degeneration.

Blue Light Compromises Bacterial ß-Lactamases Activity to Overcome ß-Lactam Resistance.

OBJECTIVE: In this study, we evaluated the effectiveness of antimicrobial blue light (aBL; 410 nm wavelength) against ß-lactamase-carrying bacteria and the effect of aBL on the activity of ß-lactamases. METHODS: Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae strains carrying ß-lactamases as well as a purified ß-lactamase enzymes were studied. ß-lactamase activity was assessed using a chromogenic cephalosporin hydrolysis assay. Additionally, we evaluated the role of porphyrins in the photoreaction, as well as protein degradation by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Finally, we investigated the bactericidal effect of combined aBL-ceftazidime exposure against a metallo-ß-lactamase expressing P. aeruginosa strain. RESULTS: Our study demonstrated that aBL effectively killed ß-lactamase-producing bacteria and reduced ß-lactamase activity. After an aBL exposure of 1.52 J/cm2, a 50% reduction in enzymatic activity was observed in P. aeruginosa. Additionally, we found a 40% decrease in the photoreaction activity of porphyrins following an aBL exposure of 64.8 J/cm2. We also revealed that aBL reduced ß-lactamase activity via protein degradation (after 136.4 J/cm2). Additionally, aBL markedly improved the bactericidal effect of ceftazidime (by >4-log10) in the metallo-ß-lactamase P. aeruginosa strain. CONCLUSION: Our results provide evidence that aBL compromises bacterial ß-lactamase activity, offering a potential approach to overcome ß-lactam resistance in bacteria.

Effect of 460 nm blue light PBM on human MeWo melanoma cells.

Photobiomodulation (PBM) using 460 nm blue light has been shown to have an inhibitory effect on skin cancer cells. In this study, we used a continuous LED light source with a wavelength of 460 nm and designed various combinations of power density (ranging from 6.4 to 25.6 mW) and dose (ranging from 0.96 to 30.72 J/cm2) to conduct treatment experiments on MeWo cells to investigate the effects of blue light on MeWo melanoma cells. We are focusing on cell viability, cytotoxicity, mitochondrial function, oxidative stress, and apoptosis. We found that blue light inhibits these melanoma cells through oxidative stress and DNA damage, and this inhibition intensifies at higher irradiance levels. Although the cells initially attempt to resist the stress induced by the treatment, they eventually undergo apoptosis over time. These findings contribute to understanding melanoma's molecular response to blue light PBM, lay the groundwork for future clinical applications.

Blue Light Effects on the Skin: A Post-2015 Update.

The debate surrounding the benefits versus harms of blue light have become a topic of interest recently due to increased exposure. Blue light therapy has been utilized with some success in a variety of dermatologic conditions. However, potential harms have also been documented. Currently, there is no evidence to suggest a necessity for blue light photoprotection, but there are products available with proven efficacy for those desiring protection. J Drugs Dermatol. 2024;23(6):472-476.     doi:10.36849/JDD.7665.

Differential expression of circRNAs during osteogenic/odontogenic differentiation of stem cells from apical papilla promoted by blue light-emitting diode.

BACKGROUND: Circular RNA (circRNA) is a key player in regulating the multidirectional differentiation of stem cells. Previous research by our group found that the blue light-emitting diode (LED) had a promoting effect on the osteogenic/odontogenic differentiation of human stem cells from apical papilla (SCAPs). This research aimed to investigate the differential expression of circRNAs during the osteogenic/odontogenic differentiation of SCAPs regulated by blue LED. MATERIALS AND METHODS: SCAPs were divided into the irradiation group (4 J/cm2) and the control group (0 J/cm2), and cultivated in an osteogenic/odontogenic environment. The differentially expressed circRNAs during osteogenic/odontogenic differentiation of SCAPs promoted by blue LED were detected by high-throughput sequencing, and preliminarily verified by qRT-PCR. Functional prediction of these circRNAs was performed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the circRNA-miRNA-mRNA networks were also constructed. RESULTS: It showed 301 circRNAs were differentially expressed. GO and KEGG analyses suggested that these circRNAs were associated with some signaling pathways related to osteogenic/odontogenic differentiation. And the circRNA-miRNA-mRNA networks were also successfully constructed. CONCLUSION: CircRNAs were involved in the osteogenic/odontogenic differentiation of SCAPs promoted by blue LED. In this biological process, circRNA-miRNA-mRNA networks served an important purpose, and circRNAs regulated this process through certain signaling pathways.

"When you're hurt and you need serious help you call 999." Educating children about emergency services and appropriate use of 999: An evaluation study of the Blue Light Hub app.

OBJECTIVES: In the face of unprecedented demand, the Welsh Ambulance Services University NHS Trust developed 'Blue Light Hub': a new app to educate primary school-aged children about emergency services. Our overarching aim was to examine the effectiveness of the app. DESIGN: Primary school-aged children from three schools in South Wales, UK, played with the app for 2 hours over 2 weeks in class time. Children completed quizzes to assess their knowledge and awareness of, and confidence in engaging with, emergency services before and after using the app. PARTICIPANTS: Our evaluation focused on N=393 children who completed both the pre-test and post-test quizzes. On average, children were 8-9 years old (median school year, Year 4); 47.8% were male and 50.9% were female. RESULTS: After using the app, there was a significant increase in the proportion of children who knew of appropriate actions to take in non-emergency scenarios, χ2(1) = 26.01, and could provide a question a call handler would ask them if they called 999, χ2(1) = 13.79. There was also an increase in the proportion of children who could identify an National Health Service (NHS) service that could help them if they were unwell, χ2(1) = 33.31, name different roles in the NHS, χ2(1) = 12.80 and knew how dialling 111 could help them χ2(1) = 90.05 (all p values<0.001). CONCLUSION: To our knowledge, Blue Light Hub is the first app of its kind designed to educate primary school-aged children about emergency services. Our findings provide preliminary evidence that the app supports children's knowledge and awareness of emergency services.

Blue light irradiation suppresses oral squamous cell carcinoma through induction of endoplasmic reticulum stress and mitochondrial dysfunction.

The therapeutic potential of blue light photobiomodulation in cancer treatment, particularly in inhibiting cell proliferation and promoting cell death, has attracted significant interest. Oral squamous cell carcinoma (OSCC) is a prevalent form of oral cancer, necessitating innovative treatment approaches to improve patient outcomes. In this study, we investigated the effects of 420 nm blue LED light on OSCC and explored the underlying mechanisms. Our results demonstrated that 420 nm blue light effectively reduced OSCC cell viability and migration, and induced G2/M arrest. Moreover, we observed that 420 nm blue light triggered endoplasmic reticulum (ER) stress and mitochondrial dysfunction in OSCC cells, leading to activation of the CHOP signal pathway and alterations in the levels of Bcl-2 and Bax proteins, ultimately promoting cell apoptosis. Additionally, blue light suppressed mitochondrial gene expression, likely due to its damage to mitochondrial DNA. This study highlights the distinct impact of 420 nm blue light on OSCC cells, providing valuable insights into its potential application as a clinical treatment for oral cancer.

The influence of prolonged but low intensity blue light on the physiological properties of root tubers and the accumulation of flavonoids in Tetrastigma hemsleyanum Diels et Gilg.

Tetrastigma hemsleyanum Diel et Gilg is a perennial herbaceous plant native to subtropical China with multiple medicinal applications. Supplementing with low-density blue light (BL) for 45 days (3 h/day) can not only significantly increase the yields of root tubers but also significantly increase the flavonoid content and its antioxidant activity. The chlorophyll content in the leaves of T. hemsleyanum significantly decreased, but the photosynthetic efficiency significantly increased after reaching the light saturation point. The production rate of superoxide anion radical in the leaves reached the highest peak after 1.5 h in BL and decreased at 3 h. The H2O2 content in the leaves decreased significantly, while the H2O2 content in the root tubers increased significantly at 3 h in BL. The objective of this research was to determine how the scavenging system, including antioxidant enzymes, antioxidants, and flavonoids respond to the oxidative stress induced by BL in root tubers. After exposure to BL, significant differences in the activity of APX and SOD were observed in the leaves and tubers within 3 h. By analyzing the upregulated flavonoids metabolites and key genes in metabolic pathways through the combined analysis of the flavonoid metabolic group and transcriptome in the root tubers, the upregulated accumulation of flavanols was found to be the main reason for the improvement in the antioxidant properties of flavonoids.