Modulation of Photosystem II Function in Celery via Foliar-Applied Salicylic Acid during Gradual Water Deficit Stress.

Water deficit is the major stress factor magnified by climate change that causes the most reductions in plant productivity. Knowledge of photosystem II (PSII) response mechanisms underlying crop vulnerability to drought is critical to better understanding the consequences of climate change on crop plants. Salicylic acid (SA) application under drought stress may stimulate PSII function, although the exact mechanism remains essentially unclear. To reveal the PSII response mechanism of celery plants sprayed with water (WA) or SA, we employed chlorophyll fluorescence imaging analysis at 48 h, 96 h, and 192 h after watering. The results showed that up to 96 h after watering, the stroma lamellae of SA-sprayed leaves appeared dilated, and the efficiency of PSII declined, compared to WA-sprayed plants, which displayed a better PSII function. However, 192 h after watering, the stroma lamellae of SA-sprayed leaves was restored, while SA boosted chlorophyll synthesis, and by ameliorating the osmotic potential of celery plants, it resulted in higher relative leaf water content compared to WA-sprayed plants. SA, by acting as an antioxidant under drought stress, suppressed phototoxicity, thereby offering PSII photoprotection, together with enhanced effective quantum yield of PSII photochemistry (ΦPSII) and decreased quantity of singlet oxygen (1O2) generation compared to WA-sprayed plants. The PSII photoprotection mechanism induced by SA under drought stress was triggered by non-photochemical quenching (NPQ), which is a strategy to protect the chloroplast from photo-oxidative damage by dissipating the excess light energy as heat. This photoprotective mechanism, triggered by NPQ under drought stress, was adequate in keeping, especially in high-light conditions, an equal fraction of open PSII reaction centers (qp) as of non-stress conditions. Thus, under water deficit stress, SA activates a regulatory network of stress and light energy partitioning signaling that can mitigate, to an extent, the water deficit stress on PSII functioning.

Mechanistic Insights on Salicylic Acid-Induced Enhancement of Photosystem II Function in Basil Plants under Non-Stress or Mild Drought Stress.

Photosystem II (PSII) functions were investigated in basil (Ocimum basilicum L.) plants sprayed with 1 mM salicylic acid (SA) under non-stress (NS) or mild drought-stress (MiDS) conditions. Under MiDS, SA-sprayed leaves retained significantly higher (+36%) chlorophyll content compared to NS, SA-sprayed leaves. PSII efficiency in SA-sprayed leaves under NS conditions, evaluated at both low light (LL, 200 µmol photons m-2 s-1) and high light (HL, 900 µmol photons m-2 s-1), increased significantly with a parallel significant decrease in the excitation pressure at PSII (1-qL) and the excess excitation energy (EXC). This enhancement of PSII efficiency under NS conditions was induced by the mechanism of non-photochemical quenching (NPQ) that reduced singlet oxygen (1O2) production, as indicated by the reduced quantum yield of non-regulated energy loss in PSII (ΦNO). Under MiDS, the thylakoid structure of water-sprayed leaves appeared slightly dilated, and the efficiency of PSII declined, compared to NS conditions. In contrast, the thylakoid structure of SA-sprayed leaves did not change under MiDS, while PSII functionality was retained, similar to NS plants at HL. This was due to the photoprotective heat dissipation by NPQ, which was sufficient to retain the same percentage of open PSII reaction centers (qp), as in NS conditions and HL. We suggest that the redox status of the plastoquinone pool (qp) under MiDS and HL initiated the acclimation response to MiDS in SA-sprayed leaves, which retained the same electron transport rate (ETR) with control plants. Foliar spray of SA could be considered as a method to improve PSII efficiency in basil plants under NS conditions, at both LL and HL, while under MiDS and HL conditions, basil plants could retain PSII efficiency similar to control plants.

Phytochemical Profiling and Pharmacological Evaluation of Leaf Extracts of Ruellia tuberosa L.: An In Vitro and In Silico Approach.

The present study was designed to appraise the photoprotective, antioxidant, and antibacterial bioactivities of Ruellia tuberosa leaves extracts (RtPE, RtChl, RtEA, RtAc, RtMe, and RtHMe). The results showed that, RtHMe extracts of R. tuberosa was rich in total phenolic content, i. e., 1.60 mgGAE/g dry extract, while highest total flavonoid content was found in RtAc extract, i. e., 0.40 mgQE/g. RtMe showed effective antioxidant activity (%RSA: 58.16) at the concentration of 120 µL. RtMe, RtEA and RtHMe exhibited effective in vitro antibacterial activity against Gram-negative bacteria (E. coli). In silico docking studies revealed that paucifloside (-11.743 kcal/mol), indole-3-carboxaldehyde (-7.519 kcal/mol), nuomioside (-7.275 kcal/mol), isocassifolioside (-6.992 kcal/mol) showed best docking score against PDB ID 2EX8 [penicillin binding protein 4 (dacB) from Escherichia coli, complexed with penicillin-G], PDB ID 6CQA (E. coli dihydrofolate reductase protein complexed with inhibitor AMPQD), PDB ID 2Y2I [Penicillin-binding protein 1B in complex with an alkyl boronate (ZA3)] and PDB ID 2OLV (from S. aureus), respectively. Docked phytochemicals also showed good drug likeness properties.

Anti-Inflammatory, Antimicrobial, Antioxidant and Photoprotective Investigation of Red Propolis Extract as Sunscreen Formulation in Polawax Cream.

Many activities have been described for propolis, including, antiviral, antibacterial, antifungal, anti-inflammatory, immunoregulatory, antioxidant and wound healing properties. Recently, propolis has been highlighted due to its potential application in the pharmaceutical and cosmetic industries, motivating a better understanding of its antioxidant and anti-inflammatory activities. Propolis and its main polyphenolic compounds presented high antioxidant activity, and effectiveness as broad spectrum UVB and UVA photoprotection sunscreens. Through a qualitative phytochemical screening, the ethanolic red propolis extracts (EEPV) (70% at room temperature and 70% at a hot temperature) presented a positive result for flavonoids and terpenoids. It presented an antioxidant activity for reducing 50% of DPPH of 17 and 12 µg/mL for extraction at room temperature and at a hot temperature, respectively. The UPLC-QTOF-MS/MS analysis allowed the annotation of 40 substances for EEPV-Heated and 42 substances for EEPV-Room Temperature. The IC50 results of the ABTS scavenging activity was 4.7 µg/mL for both extractions, at room temperature and at a hot temperature. Additionally, we also evaluated the cytotoxic profile of propolis extracts against macrophage (RAW 264.7 cells) and keratinocytes (HaCaT cells), which showed non-cytotoxic doses in cell viability assays even after a long period of exposure. In addition, propolis extracts showed antibacterial activity for Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), demonstrating potential biological activity for the creation of formulations aimed at disease control and prevention.

The Photoprotective Protein PsbS from Green Microalga Lobosphaera incisa: The Amino Acid Sequence, 3D Structure and Probable pH-Sensitive Residues.

PsbS is one of the key photoprotective proteins, ensuring the tolerance of the photosynthetic apparatus (PSA) of a plant to abrupt changes in irradiance. Being a component of photosystem II, it provides the formation of quenching centers for excited states of chlorophyll in the photosynthetic antenna with an excess of light energy. The signal for "turning on" the photoprotective function of the protein is an excessive decrease in pH in the thylakoid lumen occurring when all the absorbed light energy (stored in the form of transmembrane proton potential) cannot be used for carbon assimilation. Hence, lumen-exposed protonatable amino acid residues that could serve as pH sensors are the essential components of PsbS-dependent photoprotection, and their pKa values are necessary to describe it. Previously, calculations of the lumen-exposed protonatable residue pKa values in PsbS from spinach were described in the literature. However, it has recently become clear that PsbS, although typical of higher plants and charophytes, can also provide photoprotection in green algae. Namely, the stress-induced expression of PsbS was recently shown for two green microalgae species: Chlamydomonas reinhardtii and Lobosphaera incisa. Therefore, we determined the amino acid sequence and modeled the three-dimensional structure of the PsbS from L. incisa, as well as calculated the pKa values of its lumen-exposed protonatable residues. Despite significant differences in amino acid sequence, proteins from L. incisa and Spinacia oleracea have similar three-dimensional structures. Along with the other differences, one of the two pH-sensing glutamates in PsbS from S. oleracea (namely, Glu-173) has no analogue in L. incisa protein. Moreover, there are only four glutamate residues in the lumenal region of the L. incisa protein, while there are eight glutamates in S. oleracea. However, our calculations show that, despite the relative deficiency in protonatable residues, at least two residues of L. incisa PsbS can be considered probable pH sensors: Glu-87 and Lys-196.

A simple and reliable isocratic high-performance chromatographic assay for the simultaneous determination of hydrophilic benzophenone-4 and lipophilic octocrylene in sunscreens.

OBJECTIVE: This work aimed to develop a simple HPLC method for the simultaneous quantitative determination of the ultraviolet (UV) filters, hydrophilic benzophenone-4 and lipophilic octocrylene, in the presence of three other commonly used UV filters, avobenzone, octisalate and homosalate. METHODS: Reverse-phased HPLC was performed on a C18 column. A scouting gradient was initially used to determine the approximate mobile phase composition required for efficient analyte elution and separation before further optimization. The assay was validated with regard to specificity, linearity, intra- and inter-day accuracy and precision, limits of detection and limits of quantification. An ultrasound dispersion extraction method for the UV filters from a commercial sunscreen was developed, and the extraction efficiencies from spiked samples were calculated. RESULTS: An acetonitrile-methanol-water mixture (20:67:13, v/v/v), where the water component contained 0.2% trifluoroacetic acid (v/v), was found to be the optimal mobile phase at a flow rate of 1.0 mL/min. The assay was linear between 1.0-100 µg/mL for both benzophenone-4 and octocrylene (both correlation coefficients were above 0.999). There was no interference from the excipients of the sunscreen nor from the three other UV filters. The intra- and inter-day accuracy was between 90.0-104.6% for both analytes. Extraction recoveries from a spiked commercial sunscreen were between 95.4 ± 2.1% to 98.5 ± 2.1% for benzophenone-4, and between 87.3 ± 2.3% and 98.9 ± 3.1% for octocrylene. All validation parameters were within the acceptance criteria set out in the International Council for Harmonization (ICH) guidelines. The HPLC assay showed the extracted quantities of benzophenone-4 and octocrylene from the commercial sunscreen closely matched claimed quantities. CONCLUSION: The developed isocratic HPLC method was suitable for simultaneously determining the hydrophilic benzophenone-4 and lipophilic octocrylene in the presence of other commonly used UV filters. Additionally, the extraction method was simple and effective for accurately quantifying the UV filters in a commercial sunscreen.

OBJECTIF: Ces travaux visaient à développer une méthode de chromatographie en phase liquide à haute performance simple pour la détermination quantitative simultanée de la benzophénone-4 hydrophile et de l'octocrylène lipophile, des filtres ultraviolets (UV), en présence de trois autres filtres UV couramment utilisés, l'avobenzone, l'octisalate et l'homosalate. MÉTHODES: Une chromatographie en phase liquide à haute performance en phase inverse a été réalisée sur une colonne C18. Un gradient de référence a été initialement utilisé pour déterminer la composition approximative de la phase mobile requise pour une élution et une séparation efficace de l'analyte avant une optimisation plus poussée. Le dosage a été validé en termes de spécificité, de linéarité, d'exactitude et de précision intra- et inter-journalières, de limites de détection et de limites de quantification. Une méthode d'extraction par dispersion ultrasonique des filtres UV d'une crème solaire commerciale a été mise au point, et les efficacités d'extraction des échantillons artificiellement traités ont été calculées. RÉSULTATS: Un mélange acétonitrile-méthanol-eau (20:67:13, v/v/v), où la composante eau contenait 0,2 % d'acide trifluoroacétique (v/v), s'est avéré être la phase mobile optimale à un débit de 1,0 ml/min. Le dosage était linéaire entre 1,0 et 100 µg/ml pour la benzophénone-4 et l'octocrylène (les deux coefficients de corrélation étaient supérieurs à 0,999). Aucune interférence n'a été observée entre les excipients de l'écran solaire et les trois autres filtres UV. La précision intra et inter-journalière était comprise entre 90,0 et 104,6 % pour les deux analytes. Les récupérations par extraction à partir d'une crème solaire commerciale artificiellement traitée étaient comprises entre 95,4 % ± 2,1 % et 98,5 % ± 2,1 % pour la benzophénone-4, et entre 87,3 % ± 2,3 % et 98,9 % ± 3,1 % pour l'octocrylène. Tous les paramètres de validation étaient conformes aux critères d'acceptation définis dans les lignes directrices du Conseil international d'harmonisation (ICH). Le dosage par chromatographie en phase liquide à haute performance a montré que les quantités extraites de benzophénone-4 et d'octocrylène de la crème solaire commerciale correspondaient étroitement aux quantités revendiquées. CONCLUSION: La méthode de chromatographie en phase liquide à haute performance isocratique mise au point a permis de déterminer simultanément la benzophénone-4 hydrophile et l'octocrylène lipophile en présence d'autres filtres UV couramment utilisés. En outre, la méthode d'extraction était simple et efficace pour quantifier avec précision les filtres UV dans une crème solaire commerciale.

Identification of Cyanobacteria-Based Natural Inhibitors Against SARS-CoV-2 Druggable Target ACE2 Using Molecular Docking Study, ADME and Toxicity Analysis.

In 2019-2020, the novel "severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)" had emerged as the biggest challenge for humanity, causing "coronavirus disease 19 (COVID-19)". Scientists around the world have been putting continuous efforts to unfold potential inhibitors of SARS-CoV-2. We have performed computational studies that help us to identify cyanobacterial photoprotective compounds as potential inhibitors against SARS-CoV-2 druggable target human angiotensin-converting enzyme (ACE2), which plays a vital role in the attachment and entry of the virus into the cell. Blocking the receptor-binding domain of ACE2 can prevent the access of the virus into the compartment. A molecular docking study was performed between photoprotective compounds mycosporine-like amino acids, scytonemins and ACE2 protein using AutoDock tools. Among sixteen molecularly docked metabolites, seven compounds were selected with binding energy < 6.8 kcal/mol. Afterwards, drug-likeness and toxicity of the top candidate were predicted using Swiss ADME and Pro Tox-II online servers. All top hits show desirable drug-likeness properties, but toxicity pattern analysis discloses the toxic effect of scytonemin and its derivatives, resulting in the elimination from the screening pipeline. Further molecular interaction study of the rest two ligands, mycosporine-glycine-valine and shinorine with ACE2 was performed using PyMol, Biovia Discovery studio and LigPlot+. Lastly biological activity of both the ligands was predicted by using the PASS online server. Combining the docking score and other studied properties, we believe that mycosporine-glycine-valine and shinorine have potential to be potent inhibitors of ACE2 and can be explored further to use against COVID-19.

Photoprotective effects of sphingomyelin-containing milk phospholipids in ultraviolet B-irradiated hairless mice by suppressing nuclear factor-κB expression.

Ceramide-containing phospholipids improve skin hydration and barrier function and are ideal for use in skin care products. In this study, we evaluated the photoprotective effect of milk phospholipids on the skin condition of UVB-irradiated hairless mice. Skin parameters were assessed following oral administration of milk phospholipids. The UVB irradiation induced photoaging in mice. The animals were divided into 5 groups: a control group (oral administration of saline with no UBV irradiation), UVB group (oral administration of saline with UVB irradiation), and 3 UVB irradiation groups receiving the milk phospholipids at 3 different concentrations of oral administration, 50 mg/kg (ML group), 100 mg/kg (MM group), and 150 mg/kg (MH group), for 8 wk. An increase in skin hydration and transepidermal water loss were improved in the 150 mg/kg of milk phospholipid-administered group. Hematoxylin and eosin staining revealed a decrease in epidermal thickness in the milk phospholipid-administered groups (50, 100, and 150 mg/kg of body weight). In particular, the 100 and 150 mg/kg groups showed significant changes in the area, length, and depth of the wrinkles compared with the UVB group. Moreover, the gene expression of matrix metalloproteins was attenuated, and that of proinflammatory cytokines, especially tumor necrosis factor-α, was significantly reduced in the milk phospholipid-administered groups than in the UVB group. The reduced ceramide and increased sphingosine-1-phosphate levels in the skin tissue due to UVB exposure were restored to levels similar to those of the control group following milk phospholipid administration. These results were confirmed to be due to the downregulation of protein expression of nuclear factor kappa-B (NF-κB) and phosphorylated IκB-α (inhibitor of κB α). Collectively, oral administration of milk phospholipids improves skin health through a synergistic effect on photoprotective activity.

PROSPECT-PMP+: Simultaneous Retrievals of Chlorophyll a and b, Carotenoids and Anthocyanins in the Leaf Optical Properties Model.

The PROSPECT leaf optical radiative transfer models, including PROSPECT-MP, have addressed the contributions of multiple photosynthetic pigments (chlorophyll a and b, and carotenoids) to leaf optical properties, but photo-protective pigment (anthocyanins), another important indicator of vegetation physiological and ecological functions, has not been simultaneously combined within a leaf optical model. Here, we present a new calibration and validation of PROSPECT-MP+ that separates the contributions of multiple photosynthetic and photo-protective pigments to leaf spectrum in the 400-800 nm range using a new empirical dataset that contains multiple photosynthetic and photo-protective pigments (LOPEX_ZJU dataset). We first provide multiple distinct in vivo individual photosynthetic and photo-protective pigment absorption coefficients and leaf average refractive index of the leaf interior using the LOPEX_ZJU dataset. Then, we evaluate the capabilities of PROSPECT-MP+ for forward modelling of leaf directional hemispherical reflectance and transmittance spectra and for retrieval of pigment concentrations by model inversion. The main result of this study is that the absorption coefficients of chlorophyll a and b, carotenoids, and anthocyanins display the physical principles of absorption spectra. Moreover, the validation result of this study demonstrates the potential of PROSPECT-MP+ for improving capabilities in remote sensing of leaf photosynthetic pigments (chlorophyll a and b, and carotenoids) and photo-protective pigment (anthocyanins).

Non-Photochemical Quenching: From Light Perception to Photoprotective Gene Expression.

Light is essential for photosynthesis but light levels that exceed an organism's assimilation capacity can cause serious damage or even cell death. Plants and microalgae have developed photoprotective mechanisms collectively referred to as non-photochemical quenching to minimize such potential damage. One such mechanism is energy-dependent quenching (qE), which dissipates excess light energy as heat. Over the last 30 years, much has been learned about the molecular mechanism of qE in green algae and plants. However, the steps between light perception and qE represented a gap in our knowledge until the recent identification of light-signaling pathways that function in these processes in the green alga Chlamydomonas reinhardtii. In this review, we summarize the high light and UV-mediated signaling pathways for qE in Chlamydomonas. We discuss key questions remaining about the pathway from light perception to photoprotective gene expression in Chlamydomonas. We detail possible differences between green algae and plants in light-signaling mechanisms for qE and emphasize the importance of research on light-signaling mechanisms for qE in plants.

Rhodophyta as Potential Sources of Photoprotectants, Antiphotoaging Compounds, and Hydrogels for Cosmeceutical Application.

Seaweeds are macroscopic, multicellular, eukaryotic and photosynthetic organisms, and are a source of chemical diversity with powerful biological activities for diversified industrial applications including cosmeceuticals. Red seaweeds (Rhodophyta) are good sources of Mycosporine-like amino acids (MAA) for photoprotectant and antiphotoaging compounds. In addition, Rhodophyta are also good sources for hydrogel compounds that are used widely in the food, pharmaceutical and cosmeceutical industries as gelling agents, moisturizers or for their antiphotoaging effects. Our survey and ongoing studies revealed that the biodiversity of Indonesian Rhodophyta is rich and is a treasure trove for cosmeceutical agents including MAA and hydrogels. This study delivers valuable information for identifying potential red seaweeds in screening and searching for cosmeceutical agents.

Process Optimization of Phytoantioxidant and Photoprotective Compounds from Carob Pods (Ceratonia siliqua L.) Using Ultrasonic Assisted Extraction Method.

The current study first describes the extraction of phytoantioxidant polyphenols from Carob byproducts (pods) using maceration and heating-assisted extraction as traditional methods and ultrasonic-assisted extraction (UAE) as an innovative method to determine the most efficient extraction process in terms of four targeted responses: total phenolic content (TPC), antioxidant activities (TAC and DPPH), and photoprotective properties as measured by the sun protection factor (SPF). Second, we used response surface methodology (RSM) with a central composite rotatable design (CCDR) approach to investigate the influence of process variables (extraction time, extraction temperature, and solvent concentration) on UAE, which was found to be the most effective extraction technique in our study. Carob byproduct extracts had a TPC ranging from 6.21 to 21.92 mg GAE/g dw, a TAC ranging from 22.00 to 49.30 mg AAE/g dw, DPPH scavenging activity ranging from 56.35 to 90.50%, and SPF values ranging from 8.62 to 22.37. The optimal UAE conditions for maximum TPC, TAC, DPPH, and SPF responses were determined to be 38.90% ethanol, 53.90 °C, and 50.92 min. Using Carob as a source for sustainable and bioactive products in conjunction with optimized UAE is a promising contribution to the cosmetic industry that will help to strengthen the concept of environmentally-friendly "green chemistry". Given that Carob pulp or seeds are considered food byproducts, the research presented here encourages the use of these agri-food waste materials in cosmetics.

Photoprotective compounds and radioresistance in pigmented and non-pigmented yeasts.

Ultraviolet radiation, continuously reaching our planet's surface, is a type of electromagnetic energy within the wavelength range of 10 to 400 nm. Despite essential for all life on Earth, ultraviolet radiation may have severe adverse cellular effects, including DNA dimerization and production of reactive oxygen species. Radioresistant microorganisms can survive under high doses of ultraviolet radiation, enduring the direct and indirect effects on nucleic acids and other biomolecules. The synthesis and accumulation of photoprotective compounds are among the main strategies employed by radioresistant yeast species to bear the harmful effects of ultraviolet radiation. A correlation between pigments and resistance to ultraviolet radiation has been widely recognized in these microorganisms; however, there is still some debate on this topic, with non-pigmented strains sometimes being more resistant than their pigmented counterparts. In this review, we explore the role of photoprotective compounds-specifically, melanin, carotenoids, and mycosporines-and compare the differences found in resistance between pigmented and non-pigmented yeasts. We also discuss the biotechnological potential of these photoprotective compounds, with special emphasis on those produced by non-pigmented yeast strains, such as phytoene and phytofluene. The use of "-omics" approaches should further unveil the radioresistance mechanisms of non-pigmented yeasts, opening new opportunities for both research and commercial applications. KEY POINTS: • Updated knowledge on photoprotective compounds from radioresistant yeasts. • Differences on radioresistance between pigmented and non-pigmented yeasts. • Future prospects over the study of non-pigmented photoprotective compounds.

Comparison of skin cancer awareness and sun protection behaviours between renal transplant recipients and patients with glomerular disease treated with immunosuppressants.

BACKGROUND: There is no previous study that compare skin cancer awareness and photoprotective behaviours between renal transplant recipients (RTR) and patients with glomerular disease (GD). OBJECTIVES/METHODS: Sixty-one RTR and 51 patients with GD were given a self-reported questionnaire to evaluate skin cancer awareness and photoprotective behaviours in this cross-sectional study. The former group received a formal education on skin cancer and the latter an informal session prior to immunosuppressant use. RESULTS: Ninety-three percent (n = 57) of RTRs and 88% (n = 45) of patients with GD responded to the survey. Majority of participants from both groups were aware that ultraviolet radiation could play a role in the occurrence of skin cancers and the awareness increased in participants with higher education (odds ratio [OR] = 1.50, 95% confidence interval [CI] = 1.15-1.95, P = .003). Ninety-eight percent vs 71% were aware that immunosuppressants can increase the risk of developing cancer (P < .001) and higher awareness was noted in younger participants (OR = 0.92, 95% CI = 0.87-0.97, P = .003). Suboptimal photoprotective behaviours (sun avoidance, sunscreen usage and sun-protective clothing) were noted in both cohorts and slightly lower sun protection rates were reported in RTR when compared with patients having GD. The level of sun protective measures in RTR based on high, moderate and minimal use of photoprotective measures were 21%, 46% and 33%, respectively. In terms of patients with GD, the latter practices were 13%, 50% and 37%, respectively (P = .560). Higher educational status was significantly associated with better sunscreen usage in RTR (P = .017) whereas this finding was not observed in patients with GD. CONCLUSION: Patients with GD and RTR should have formal education on the risks of skin cancers before starting immunosuppressants. Follow-up education and surveillance is required to improve skin protective practices in these patients.

Unravelling the Dermatological Potential of the Brown Seaweed Carpomitra costata.

The ever-increasing interest in keeping a young appearance and healthy skin has leveraged the skincare industry. This, coupled together with the increased concern regarding the safety of synthetic products, has boosted the demand for new and safer natural ingredients. Accordingly, the aim of this study was to evaluate the dermatological potential of the brown seaweed Carpomitra costata. The antioxidant, anti-enzymatic, antimicrobial, photoprotective and anti-inflammatory properties of five C. costata fractions (F1-F5) were evaluated. The ethyl acetate fraction (F3) demonstrated the most promising results, with the best ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals (EC50 of 140.1 µg/mL) and the capacity to reduce reactive oxygen species (ROS) production promoted by UVA and UVB radiation in 3T3 cells, revealing its antioxidant and photoprotective potential. This fraction also exhibited the highest anti-enzymatic capacity, inhibiting the activities of collagenase, elastase and tyrosinase (IC50 of 7.2, 4.8 and 85.9 µg/mL, respectively). Moreover, F3 showed anti-inflammatory potential, reducing TNF-α and IL-6 release induced by LPS treatment in RAW 264.7 cells. These bioactivities may be related to the presence of phenolic compounds, such as phlorotannins, as demonstrated by NMR analysis. The results highlight the potential of C. costata as a source of bioactive ingredients for further dermatological applications.

Phlorotannin and Pigment Content of Native Canopy-Forming Sargassaceae Species Living in Intertidal Rockpools in Brittany (France): Any Relationship with Their Vertical Distribution and Phenology?

Five native Sargassaceae species from Brittany (France) living in rockpools were surveyed over time to investigate photoprotective strategies according to their tidal position. We gave evidences for the existence of a species distribution between pools along the shore, with the most dense and smallest individuals in the highest pools. Pigment contents were higher in lower pools, suggesting a photo-adaptive process by which the decreasing light irradiance toward the low shore was compensated by a high production of pigments to ensure efficient photosynthesis. Conversely, no xanthophyll cycle-related photoprotective mechanism was highlighted because high levels of zeaxanthin rarely occurred in the upper shore. Phlorotannins were not involved in photoprotection either; only some lower-shore species exhibited a seasonal trend in phlorotannin levels. The structural complexity of phlorotannins appears more to be a taxonomic than an ecological feature: Ericaria produced simple phloroglucinol while Cystoseira and Gongolaria species exhibited polymers. Consequently, tide pools could be considered as light-protected areas on the intertidal zone, in comparison with the exposed emerged substrata where photoprotective mechanisms are essential.

Photoprotective habits in children with systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is a complex autoimmune disease that can involve multiple organ systems. Exposure to ultraviolet radiation (UVR) can exacerbate pre-existing SLE, and can even induce systemic manifestations. This study aimed to investigate the photoprotective habits of children with SLE and the factors that significantly influence those photoprotective habits. METHODS: This questionnaire-based cross-sectional study included paediatric SLE patients being treated at the Department of Paediatrics at Siriraj Hospital, Mahidol University, between September 2018 and September 2019. Data were obtained from medical records and a face-to-face interview. RESULTS: Ninety-six patients were enrolled, with a female-to-male ratio of 8:1. The mean age of patients at enrollment was 13.7 ± 2.4 years. Of the 96 patients, 70 (72.9%) reported being directly exposed to sunlight for less than two hours per day, but 39% of patients spent time in the sun during the peak hours of UVR. Up to 95% of patients used sunscreen. However, only 64% of patients applied it every day, and only 35% of patients used an adequate amount of sunscreen. Girls were significantly more likely to apply sunscreen every day than boys were (p = 0.041). SLE patients with a shorter disease duration had significantly greater exposure to sunlight than patients with a disease duration of more than four years (p = 0.040). CONCLUSION: Sunscreen was the most common photoprotective method. However, most patients used sunscreen inappropriately. A shorter disease duration was significantly associated with more sunlight exposure. Regular evaluation and emphasis of the importance of photoprotection should be encouraged among paediatric SLE.

Synthesis and evaluation of antioxidant and antiproliferative activity of 2-arylbenzimidazoles.

Three series of arylbenzimidazole derivatives 3-40, 45 have been simply synthesized and tested for their antioxidant capacity. The 2-arylbenzimidazoles were tested against various radicals by the DPPH, FRAP and ORAC tests and showed different activity profiles. It has been observed that the number and position of the hydroxy groups on the 2-aryl portion and the presence of a diethylamino group or a 2-styryl group are related to a good antioxidant capacity. Furthermore, benzimidazoles showed satisfactory SPF values ​​in vitro compared to the commercial PBSA filter, proving to have a good photoprotective profile. In particular, 2-arylbenzimidazole-5-sulphonic acids 15 and 38, the 2-styryl-benzimidazole 45 showed broad spectrum solar protection against UVA and UVB rays. The antiproliferative effect of the benzimidazoles was tested on human skin melanoma Colo-38 cells. The styrylbenzimidazole 45 exhibited antiproliferative effect at low micromolar concentration against Colo-38 cells and very low antiproliferative activity on normal HaCat keratinocyte cells.

Mycosporine-Like Amino Acids (MAAs) in Zooplankton.

Organisms have different adaptations to avoid damage from ultraviolet radiation and one such adaptation is the accumulation of mycosporine-like amino acids (MAAs). These compounds are common in aquatic taxa but a comprehensive review is lacking on their distribution and function in zooplankton. This paper shows that zooplankton MAA concentrations range from non-detectable to ~13 µg mgDW-1. Copepods, rotifers, and krill display a large range of concentrations, whereas cladocerans generally do not contain MAAs. The proposed mechanisms to gain MAAs are via ingestion of MAA-rich food or via symbiotic bacteria providing zooplankton with MAAs. Exposure to UV-radiation increases the concentrations in zooplankton both via increasing MAA concentrations in the phytoplankton food and due to active accumulation. Concentrations are generally low during winter and higher in summer and females seem to deposit MAAs in their eggs. The concentrations of MAAs in zooplankton tend to increase with altitude but only up to a certain altitude suggesting some limitation for the uptake. Shallow and UV-transparent systems tend to have copepods with higher concentrations of MAAs but this has only been shown in a few species. A high MAA concentration has also been shown to lead to lower UV-induced mortality and an overall increased fitness. While there is a lot of information on MAAs in zooplankton we still lack understanding of the potential costs and constraints for accumulation. There is also scarce information in some taxa such as rotifers as well as from systems in tropical, sub(polar) areas as well as in marine systems in general.

Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis.

To explore the mechanisms underlying the action of the heavy metals Cd and Zn on the photosynthetic function of plant leaves, the effects of 100 µmol L-1 Cd and 200 µmol L-1 Zn stress (the exposure concentrations of Cd and Zn in the culture medium were 2.24 mg kg-1 and 5.36 mg kg-1) on the chlorophyll and carotenoid contents as well as the photosynthetic function of tobacco leaves (Long Jiang 911) were studied. The key proteins in these physiological processes were quantitatively analyzed using a TMT-based proteomics approach. Cd stress was found to inhibit the expression of key enzymes during chlorophyll synthesis in leaves, resulting in a decrease of the Chl content. However, Zn stress did not significantly influence the chlorophyll content. Leaves adapted to Zn stress by upregulating CAO expression and increase the Chl b content. Although the Car content in leaves did not significantly change under either Cd or Zn stress, the expressions of ZE and VDE during Car metabolism decreased significantly under Cd stress. This was accompanied by damages to the xanthophyll cycle and the NPQ-dependent energy dissipation mechanism. In contrast, under Zn stress, leaves adapted to Zn stress by increasing the expression of VDE, thus improving NPQ. Under Cd stress, the expressions of three sets of proteins were significantly down-regulated, including PSII donor-side proteins (PPD3, PPD6, OEE1, OEE2-1, OEE2-2, OEE2-3, and OEE3-2), receptor-side proteins (D1, D2, CP43, CP47, Cyt b559α, Cyt b559ß, PsbL, PsbQ, PsbR, Psb27-H1, and Psb28), and core proteins of the PSI reaction center (psaA, psaB, psaC, psaD, psaE-A, PsaE-B, psaF, psaG, psaH-1, psaK, psaL, psaN, and psaOL). In comparison, only eight of the above proteins (PPD6, OEE3-2, PsbL, PsbQ, Psb27-H1, psaL, and psaOL) were significantly down-regulated by Zn stress. Under Cd stress, both the donor side and the receptor side of PSII were damaged, and PSII and PSI experienced severe photoinhibition. However, Zn stress did not decrease either PSII or PSI activities in tobacco leaves. In addition, the expression of electron transport-related proteins (cytb6/f complex, PC, Fd, and FNR), ATPase subunits, Rubisco subunits, and RCA decreased significantly in leaves under Cd stress. However, no significant changes were observed in any of these proteins under Zn stress. Although Cd stress was found to up-regulate the expressions of PGRL1A and PGRL1B and induce an increase of PGR5/PGRL1-CEF in tobacco leaves, NDH-CEF was significantly inhibited. Under Zn stress, the expressions of ndhH and PGRL1A in leaves were significantly up-regulated, but there were no significant changes in either NDH-CEF or PGR5/PGRL-CEF. Under Cd stress, the expressions of proteins related to Fd-dependent nitrogen metabolism and reactive oxygen species (ROS) scavenging processes (e.g., FTR, Fd-NiR, and Fd-GOGAT) were significantly down-regulated in leaves. However, no significant changes of any of the above proteins were identified under Zn stress. In summary, Cd stress could inhibit the synthesis of chlorophyll in tobacco leaves, significantly down-regulate the expressions of photosynthesis-related proteins or subunits, and suppress both the xanthophyll cycle and NDH-CEF process. The expressions of proteins related to the Fd-dependent nitrogen metabolism and ROS scavenging were also significantly down-regulated, which blocked the photosynthetic electron transport, thus resulting in severe photoinhibition of both PSII and PSI. However, Zn stress had little effect on the photosynthetic function of tobacco leaves.