In vitro approaches to antioxidant screening for the development of a sunscreen formulation

Abstract The incorporation of antioxidants into sunscreens may provide additional skin photoprotection against the harmful photobiological effects of ultraviolet radiation. The present study evaluated the applicability of a screening approach to the assessment of the antioxidant and photoprotective properties of vitamin C, vitamin E, and coenzyme Q10 and then determined the performance of the most effective antioxidant in a sunscreen formulation. Antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2`-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and oxygen radical absorbance capacity (ORAC) assay, and the photoprotective potential was investigated by the yeast photoprotection assay. The antioxidant with the best effect was incorporated into sunscreen formulations which were evaluated for 120 days regarding their in vitro photoprotective parameters. Vitamin C showed high antioxidant capacity as well as a photoprotective potential against simulated solar irradiation applied for times longer than 1 h. Although the Sun Protection Factor, UVA/UVB ratio and critical wavelength did not differed significantly (p<0.05) between the formulation blank and the formulations containing 0.5% or 1% vitamin C, formulations with vitamin C kept their photostability for 6 months. Consequently, the proposed screening approach seems to be promising for the development of an antisolar photostable formulation containing vitamin C as an antioxidant.

Association of Rhizophora mangle and ascorbic acid in hydrogels: Evaluation of cytotoxic and immunomodulatory effects

Abstract Polyphenolics from Rhizophora mangle (R. mangle) have shown wound healing and anti- inflammatory effects that may be potentiated by being associated with ascorbic acid, an important substance for collagen and elastin synthesis that plays a role in tissue repair. In our study, we aimed to formulate an association of R. mangle and ascorbic acid in hydrogels and evaluate the association's cytotoxic and immunomodulatory effects. In a pre-formulation study, three gelling polymers (i.e.xanthan gum, poloxamer and hydroxyethyl cellulose) were tested. The selected polymer (i.e. xanthan gum) was used to evaluate cytotoxic and immunomodulatory effects using flow cytometry. Xanthan gum (1.5%) had a homogeneous appearance, an orange colour, a smooth surface, intense brightness and the typical odour, as well as non-Newtonian pseudoplastic behaviour. With a pH of 5.0-5.3 and a non-cytotoxic profile, xanthan gum induced the proliferation and activation of CD4 +, CD8+ and NK T lymphocytes and the production of IL- 2, IL-4, IL-10, IL-17 and TNF-α cytokines in stimulated splenocytes. The results suggest that the association of R. mangle and ascorbic acid in 1.5% xanthan gum hydrogel may be promising in preparations for wound-healing processes

Impact of supplemental vitamins and natural honey for treatment of COVID-19: A review

Abstract The main aim of the paper is to assess whether vitamin C, vitamin D, and natural honey can be administered in the course of the COVID-19 pandemic for promising in line methods with recent evidence. Both systematic literature and clinical trial identification were conducted by searching various databases. A total 58 articles and 29 clinical trials were selected wherein 11 for vitamin C, 16 for vitamin D, and 2 for natural honey were identified for analysis. The high doses of vitamin C (i.e. '200 mg/kg body weight/day, divided into 4 doses') has been found to reduce COVID-19 lung damage, various flu infections. Additionally, the high doses of vitamin C can shorten around 7.8% stay in the intensive care unit. At the same time, vitamin D can effectively protect from lung injury and acute respiratory infections whereas vitamin D deficiency severely affects 75% of the institutionalized people (serum 25(OH) D < 25 nmol/L). Meanwhile, natural honey which contains proteins (0.1-0.4%); ash (0.2%); water (15-17%) has potential antiviral effects and the ability to improve immunity. Therefore, the administration of vitamins and honey is the promising evidence-based approach for reducing fatalities, saving lives, and bringing the COVID-19 pandemic to a rapid end. It is believed that the utilization of vitamin C, vitamin D, and natural honey with the current treatment may be effective in treating COVID-19-caused fatal complications such as pneumonia. Therefore, high-level clinical studies are required on COVID-19 to administrate the effects of vitamins and natural honey

DNA damage in a solution containing copper(II) ions and ascorbic acid: Effect of the presence of sulfite

Some antioxidant compounds have a pro-oxidant effect in the presence of transition metal ions, due to the reduction of Mn+ to M(n-1)+ with simultaneous formation of free radicals, which then promote DNA damage. In the present study, we evaluated the pUC19 DNA damage in a solution containing Cu(II) and ascorbic acid (AA) or S(IV) saturated with air by agarose gel electrophoresis. Our results showed that this damage decreases if AA and S(IV) are simultaneously added. This study also illustrates the importance of Cu(II) in this process, as no DNA damage was observed when AA or S(IV) were present in the absence of this metallic ion. Our data showed that DNA preservation depends on the concentration of AA and S(IV) and occurs when the [S(IV)]:[AA] ratio ranges from 1:1 to 20:1. Absorbance measurements and thermodynamic data show that no reaction occurs between AA and S(IV) when this mixture (pH 5.5) is added to pUC-19 DNA. The presence of dissolved oxygen may be the cause of AA consumption in the mixture of these two antioxidants, which subsequently decreases DNA damage.

Synergetic effect of chitosan and vitamin C on the oxidative enzyme status in rat exposed to lead acetate / Efeito sinérgico do chitosano e da vitamina C no estado da enzima oxidativa em ratos expostos ao acetato de chumbo

This article discusses the research results on the synergetic effect of chitosan and vitamin C in overcoming free radical effect due to blood lead (Pb2+) accumulation. Blood lead level and enzymatic activities of superoxide dismutase (SOD), catalase oxidase (CAT), and Glutathione peroxidase (GPx) were used as the main parameters. Thirty adult male albino rats were divided into six groups. Group 1 was normal control group; group 2 was the negative control group treated with lead acetate at 175 mg kg-1 body weight (BW). Group 3 was treated with 64 mg kg-1 BW of chitosan day-1. Group 4, 5, and 6 were treated with chitosan and vitamin C combination at the dose of 100, 200, and 300 mg kg-1 BW, respectively. All groups were inducted using 175 mg kg-1 BW of Pb-acetate, excluding control group. Results showed that chitosan and vitamin C treatment at the dose of 300 mg kg-1 BW decreased blood Pb2+ level in rats exposed to Pb-acetate. The combination also significantly increased enzymatic activities from SOD, CAT, and GPx compared to the other groups. In conclusion, the combination of chitosan and vitamin C could elevate the several antioxidative enzymes activities in Pb-acetate induced rats.

Este artigo discute os resultados da pesquisa sobre o efeito sinérgico da quitosana e da vitamina C na superação do efeito dos radicais livres devido ao acúmulo de chumbo no sangue (Pb2+). O nível de chumbo no sangue e as atividades enzimáticas de superóxido dismutase (SOD), catalase oxidase (CAT) e glutationa peroxidase (GPx) foram utilizados como parâmetros principais. Trinta ratos albinos adultos foram divididos em seis grupos. Grupo 1 foi grupo controle normal; o grupo 2 foi o grupo controle negativo tratado com acetato de chumbo a 175 mg kg-1 de peso corporal (PC). O grupo 3 foi tratado com 64 mg kg-1 PC de quitosana dia-1. Os grupos 4, 5 e 6 foram tratados com combinação de quitosana e vitamina C nas doses de 100, 200 e 300 mg kg-1 PC, respectivamente. Todos os grupos foram induzidos usando 175 mg kg-1 de PC de Pb-acetato, excluindo o grupo controle. Os resultados mostraram que o tratamento com quitosana e vitamina C na dose de 300 mg kg-1 PC diminuiu o nível de Pb2+ no sangue em ratos expostos ao acetato de Pb. A combinação também aumentou significativamente as atividades enzimáticas de SOD, CAT e GPx em comparação com os outros grupos. Em conclusão, a combinação de quitosana e vitamina C pode elevar as várias atividades das enzimas antioxidativas em ratos induzidos com acetato de Pb.

Efeito da Laserfototerapia associada ou não à Vitamina C na indução de membranas celulares (cell sheets) de células-tronco da polpa dentária humana / Effect of laserphototherapy associated or not to Vitamin C in the induction of cell sheets of human dental pulp stem cells

Membranas celulares (MCs; Cell Sheets), constituídas por células-tronco (CTs), são autodestacáveis da placa de cultivo, e sem subcultivos geram grande quantidade de células que podem ser transplantadas de maneira mais próxima da fisiologia celular, mantendo-se as ligaçُões celulares e a matriz extracelular produzidas em cultura. O Ácido ascórbico ou vitamina C (VC) tem efeito indutor da formação destas MCs, aumentando a longevidade e tempo de indiferenciação das CTs. A similaridade observada entre respostas biológicas da VC em MCs e aquelas da Laserfototerapia (LFT) sobre células e tecidos, nos levou à hipótese de que estas terapias poderiam se complementar melhorando o prognóstico de futura aplicação clínica dessas MCs em regenerações tecidos de interesse odontológico. Para testar essa hipótese, LFT e VC foram aplicadas associadas ou não na indução de MCs de células-tronco da polpa dentária humana (hDPSCs). Para tanto, hDPSCs descongeladas, que expressaram níveis típicos de marcadores de superfície de células-tronco mesenquimais, foram plaqueadas em placas de 6 poços (5x104 células por poço). Vinte e quatro horas depois do plaqueamento as culturas foram submetidas aos tratamentos dos grupos experimentais: Controle: hDPSCs em P3 cultivadas com meio clonogênico; Senescente: hDPSCs em P27 cultivadas com meio clonogênico; VC: P3 cultivadas com meio clonogênico acrescido de VC (20µg/ml); Laser: P3 cultivadas com meio clonogênico e submetido à LFT (contato e pontual - 5 pontos / poço, 660 nm, 20 mW, 0,028 cm², 0,71 W/cm², 7 segundos, 5 J/cm², 0,14 J por ponto, 48 horas de intervalo) e Laser+VC: P3 cultivadas com meio clonogênico acrescido de VC e submetido

à LFT. Em 24 horas, 7 e 13 dias as hDPSCs dos diferentes grupos experimentais foram observadas macro e microscopicamente, e atividade da enzima telomerase foi avaliada por PCR-TRAP, complementado por ELISA. Para a avaliação da expressão de genes relacionados à natureza e indiferenciação (Mitofilina e Oct 4) e à longevidade (fase catalíca da enzima telomerase - hTERT); bem como à senescência das células do grupo senescente (­­ß-galactosidase), as hDPSCs de todos os grupos experimentais foram submetidas ao RT-qPCR As hDPSCs foram capazes de formar MCs somente nos grupos VC e Laser+VC (100%), entre 10 e 13 dias. As MCs do grupo Laser+VC apresentaram maior facilidade na manipulação. Atividade de Telomerase nas hDPSCs foi observada somente em 24 horas (Controle e LFT) e em 7 dias (VC e Laser+VC). Os marcadores de indiferenciação (Oct 4) e mesenquimal (mitofilina), bem como a hTERT foram expressos nas hDPSCs de todos os grupos experimentais. O Oct4 e o hTERT, em 7 dias, apresentaram expressões significativamente maiores nos grupos VC e Laser+VC em comparação com os demais (p < 0,0001, p = 0,0009, respectivamente). A expressão da mitofilina foi significativamente maior no grupo Laser+VC, em 7 dias (p =0,033). A técnica de obtenção de MCs de hDPSCs por essa metodologia foi considerada adequada para ser testada em procedimentos regenerativos. A LFT quando associada à VC não interferiu na formação das MCs, nem na manutenção da longevidade e indiferenciação das hDPSCs. Adicionalmente, a LFT melhorou a manipulação das MCs. Assim sendo, a associação de VC e LFT na indução de MCs parece promissora para futura utilização de MCs na odontologia regenerativa.

Cell Sheets, consisting of stem cells (SCs) are self detachable from the cultivation plate, and with no subcultivation can generate large amount of cells. The cell sheets can be transplanted closer to cell physiology environment by keeping the cell connections and the extracellular matrix produced in culture. Ascorbic acid or Vitamin C (VC) has inductive effect on cell sheet formation, increasing the longevity and the stemness of the cell for long period of time. The similarity between biological responses of VC in cell sheets and those of Laserphototherapy (LPT, Laser) on cells and tissues led us to hypothesize that these therapies could improve the prognosis of future clinical application of these cell sheets in regeneration of dental tissues. To test this hypothesis, LPT and VC were applied, associated or not, to induce human dental pulp stem cells (hDPSCs). Therefore, hDPSCs, which expressed typical levels of mesenchymal stem cell surface markers, were plated in 6-well plates (5x104 cells per well). Twenty-four hours later they were subjected to the treatment of experimental groups: Control: hDPSCs in P3 cultured with regular medium; Senescent: hDPSCs in P27 cultured with regular medium; VC: P3 cultured with regular medium supplemented with VC (20 ?g/ml); Laser: P3 cultures with regular medium and submitted to LPT (punctual and contact mode-5 points / well, 660 nm, 20 mW, 0.028 cm², 0.71 W/cm²,

7 sec, 5 J/cm², 0.14 J per point, 48 hours-intervals) and Laser+VC: P3 cultured with regular medium supplemented with VC and submitted to LPT Within 24 hours, 7 and 13 days the hDPSCs of the different experimental groups were observed macroscopically and microscopically, and the telomerase enzyme activity was assessed by PCR-TRAP, complemented by ELISA. To evaluate the expression of genes related to the nature and differentiation (Mitofilina and Oct 4), longevity (catalytic phase of telomerase-hTERT enzyme), and the senescence of the senescent group cells (?-galactosidase), the hDPSCs of all experimental groups were subjected to RT-qPCR. The RT-qPCR data were compared by ANOVA complemented by the Tukey's test (p <= 0.05). The hDPSCs were able to form cell sheets only in the VC and Laser+VC groups (100%). Additionally, the cell sheets of the Laser+VC group presented easier handling...

Mega-dose vitamin C: is it harmful to the liver? biochemical and histological study in rats

To investigate if mega-doses of vitamin C would have deleterious effects on the liver in an animal model. A mega-dose of vitamin C [1000 mg/kg/day] was administered by oral gavage to male Wistar rats for 60 days. Both biochemical and histopathological measures were undertaken. The results showed that a mega-dose of vitamin C significantly elevated lipid peroxidation and transaminase activity level in addition to the significant suppression of antioxidant enzymes activities. These results were consistent with the presence of histological lesions. A mega-dose of vitamin C is not safe and can cause liver injury

Antioxidant activity of bee products added to water in tebuconazole-exposed fish

An experiment was conducted to evaluate the potential of honey, propolis, and bee pollen for the reversal of lipid peroxidation induced by tebuconazole (TEB) in South American catfish (Rhamdia quelen), in which the concentration of thiobarbituric acid reactive substances (TBARS), the activity of the antioxidant enzyme glutathione-S-transferase (GST) and the concentrations of non-enzymatic antioxidants, reduced glutathione (GSH), ascorbic acid, and non-protein thiols were assessed. Honey (0.125 g L-1) and bee pollen (0.05 g L-1) added to the water reverse the production of TBARS induced by TEB, while propolis demonstrated a pro-oxidant effect, inducing an increase in TBARS production. The data presented herein suggest that the addition of water to honey and bee pollen potentially protects against the oxidative stress caused by agrichemicals.

Um experimento foi conduzido objetivando avaliar o potencial do mel, da própolis e do pólen apícola na reversão da peroxidação lipídica causada pelo fungicida tebuconazole (TEB) na espécie de peixe tropical Rhamdia quelen, avaliando a concentração das substâncias reativas ao ácido tiobarbitúrico (TBARS), a atividade da enzima glutationa-S-transferase (GST) e das concentrações dos antioxidantes glutationa reduzida (GSH), ácido ascórbico e dos tiois não proteicos. O mel adicionado à água na concentração de 0,125g L-1 e o pólen apícola na concentração de 0.05 g L-1reverteram a geração das TBARS causada pela exposição ao TEB, enquanto a própolis demonstrou efeito pró-oxidante, induzindo um aumento na geração das TBARS. Os dados apresentados neste trabalho sugerem o potencial do mel e do pólen apícola adicionados à água como substâncias protetoras contra o estresse oxidativo causado por agroquímicos.

Effects of ascorbic acid supplementation in ileum myenteric neurons of streptozotocin-induced diabetic rats / Efeitos da suplementação do ácido ascórbico nos neurônios mientéricos do íleo de ratos diabéticos induzidos por estreptozootocina

The exacerbation of the oxidative stress and of the polyol pathway which impair damage myenteric plexus are metabolic characteristics of diabetes. The ascorbic acid (AA) is an antioxidant and an aldose reductase inhibitor, which may act as neuroprotector. The effects of AA supplementation on the density and cellular body profile area (CP) of myenteric neurons in STZ-induced diabetes in rats were assessed. Four groups with five animals each were formed: normoglycemic (C); diabetic (D); AA-treated diabetic (DS) and AA-treated normoglycemic (CS). Dosagen of 50mg of AA were given, three times a week, for each animal (group DS and CS). Ninety days later and after euthanasia, the ileum was collected and processed for the NADPH-diaphorase technique. There were no differences (P>0.05) in the neuronal density among the groups. The CP area was lower (P<0.05) in the DS and CS groups, with a higher incidence of neurons with a CP area exceeding 200µm² for groups C and D. The AA had no influence on the neuronal density in the ileum but had a neuroprotective effect, preventing the increase in the CP area and allowing a higher number of neurons with a CP area with less than 200µm².

A exacerbação do estresse oxidativo e da via do poliol que comprometem o plexo mioentérico são alterações metabólicas características do diabetes. O ácido ascórbico (AA) é antioxidante e inibidor da aldose redutase, podendo atuar como neuroprotetor. Verificaram-se os efeitos da suplementação com AA sobre o número e a área do perfil do corpo celular (PC) de neurônios mioentéricos em ratos diabéticos induzidos por estreptozootocina. Formaram-se quatro grupos com cinco animais cada: normoglicêmico (C); diabético (D); diabético tratado com AA (DS); e normoglicêmico tratado com AA (CS). Três vezes por semana administrou-se 50mg de AA para cada animal (grupos DS e CS). Após 90 dias e eutanásia com tiopental, o íleo foi coletado e processado para a técnica da NADPH-diaforase. Não se observaram diferenças (P>0,05) na densidade neuronal entre os grupos. A área do PC foi menor (P<0,05) para os grupos DS e CS, com incidência maior de neurônios com área do PC superior a 200µm² para os grupos C e D. Concluiu-se que o AA não influenciou a densidade neuronal do íleo, mas foi neuroprotetor prevenindo o aumento na área do PC e possibilitando maior incidência de neurônios com área de PC inferior a 200µm².

effect of dietary ascorbic acid on wound healing in chronic diabetic rats

Vitamin C is constituent with antioxidant power, it was reported that increasing oxidative stress in diabetes mellitus associated with decreasing in collagen synthesis. This study was performed on the possible effect of dietary vitamin C supplementation on wound healing in chronic diabetic rats. This study was performed on 160 male rats. Diabetes was induced by injection of streptozotocin [S.C, 50mg/kg]. Animals were divided into 4 groups and then rats were remained diabetic for 8 weeks. Control group [I] received the vitamin C deficient diet. Prophylaxis group [II], received 250mg/kg vitamin C which was added to their drinking water, one month before induction of diabetes. Treatment group [III], received vitamin C [250mg/kg] one month after induction of diabetes. Combination group [IV] received the vitamin C one month before diabetes induction until wound healing. Wound was made on animals by a circular 3cm[2] full thickness incision on back, 8 weeks after diabetic induction. Surface density of blood vessels and epidermal layer, content of collagen and biochemical measurement of hydroxyproline at days 1,3,7, 11, 15 and 20 after operation were measured. The mean of surface density of blood vessels and epidermal layers of group II up to day 7 was more than all groups. Also, these mentioned indicators; in group I were more than groups III and IV during all days. The mean of collagen and hydroxyproline content in group I was more than all examined groups at days of 11. The result of group III was less than group IV during all days. This data suggest that, vitamin C supplementation as prophylaxis or combination in rats with chronic diabetic could impair wound healing

Intravenous vitamin C as a chemotherapy agent: a report on clinical cases

A series of seven cases are presented in which intravenous vitamin C has been used as antineoplastic agent in the treatment of different types of cancers. The cancers cases reviewed are the following: Renal cell carcinoma (2), Colorectal cancer (1), Pancreatic cancer (1), Non-Hodgkin's lymphoma (2) and breast cancer (1). Toxic reactions were not observed at these high doses of intravenous Vitamin C. All patients were prescreened for Glucose 6--phosphate dehydrogenase deficiency before administering intravenous Vitamin C in order to prevent hemolysis

Intravenous ascorbic acid: protocol for its application and use

High dose intravenous(i.v.) ascorbic acid (AA) has been used as therapy for infectious disease from bacterial and viral origin and adjuvant therapy for cancer. In this publication we describe a clinical protocol that has been developed over the past twenty years utilizing high dose i.v. AA as therapy for cancer. This includes principles of treatment, rationale, baseline workup, infusion protocol, precautions and side effects.

Efeito interferente do ácido acórbico nas determinações de parâmetros bioquímicos séricos / Ascorbic acid interference on the measurement of serum biochemical parameters

O ácido ascórbico, quando presente em amostras biológicas, pode interferir nos ensaios laboratoriais que utilizam reações de óxido-redução. O objetivo desse estudo foi estabelecer o grau de interferência do ácido ascórbico nas determinações bioquímicas séricas em relação à dose de vitamina C ingerida por indivíduos saudáveis e ao tempo de coleta das amostras. Voluntários saudáveis (n=13) consumiram doses de 0,25 a 4,0 g/dia de vitamina C e as determinações bioquímicas foram realizadas em amostras obtidas 4, 12 e 24 h após a ingestão. Os níveis de ácido ascórbico sérico aumentaram significativamente 4 e 12 h após a ingestão das várias doses de vitamina C. Dentre os parâmetros analisados, observou-se uma diminuição significativa nos valores séricos de ácido úrico e bilirrubina, inversamente proporcional aos níveis de ácido ascórbico presentes nas amostras (r = -0,57 para urato e -0,33 para bilirrubina, p<0,05). Após o 24 h ocorreu ainda 18% de interferência para o ácido úrico com a dose de 4 g de vitamina C (p<0,05). Em contrapartida, o ácido ascórbico não interferiu nas determinações de glicose, colesterol, triglicérides, uréia, fósforo e cretinina. Para evitar resultados falso-negativos de ácido úrico e bilirrubina sugerimos a suspensão da ingestão de vitamina C em até 48 h antes da coleta de sangue para as análises.

Efecto bifásico de la ingestión de ácido ascórbico sobre la actividad de catalasa hepática y el nivel de colesterol en la rata / Biphasic effect of ascorbic acid intake on liver catalase activity and cholesterol level in the rat

Se estudió el efecto de la ingestión del ácido ascórbico durante dos diferentes períodos sobre la actividad de la catalasa hepática y el nivel del colesterol plasmático y hepático en ratas machos normales. La ingestión de ácido ascórbico durante 3 u 8 semanas no tuvo efectos significativos sobre el peso corporal y hepático ni en el contenido de colesterol hepático. Los niveles de ácido ascórbico en el plasma e higado no fueron significativamente diferentes de los valores controles después de ambos periodos de ingestión de ácido ascórbico. Mientras que la ingestión de ácido ascórbico durante 3 semanas produjo hipocolesterolemia (p<0,001) y aumentó la actividad de la catalasa hepática en 35%, la ingestión del ácido ascórbico durante 8 semanas no tuvo efectos significativos en ambos parámetros. Estos resultados sugieren que la ingestión del ácido ascórbico tiene un efecto bifásico dependiente del tiempo sobre el nivel del colesterol plasmático y la actividad de la catalasa hepática. Además, los resultados de este estudio parecen indicar que la actividad de la catalasa aumenta con la edad en la rata