Free Ascorbic Acid Research Articles

Yeast cell biocarrier for the encapsulation of ascorbic acid: effect of plasmolysis process, suspension media and ascorbic acid levels on the physicochemical, morphological and bioactive properties of microcapsules.

Ascorbic acid is a water-soluble vitamin and shows weak stability against external factors such as heat, oxygen, light etc. Due to its lower stability, encapsulation is an effective process for the preservation of its activity. Although there are a wide variety of encapsulation methods, the technique of encapsulation with yeast cells has been followed with increasing interest in recent years. In this study, encapsulation possibilities of ascorbic acid by yeast cells were investigated. In this context, Saccharomycess cerevisiae yeast cells in plasmolyzed and non-plasmolyzed forms were used in two different suspension media (water and ethanol) and effect of ascorbic acid concentrations (10, 20 and 50 g per 10 g yeast) were studied. A total of 12 different yeast microcapsule samples were produced and some physicochemical, bioactive and structural characterizations were performed. The ascorbic acid level of yeast microcapsule samples was determined as 206.4-713.9 and 202.8-726.1 mg g-1 for plasmolyzed and non-plasmolyzed yeast cell types, respectively. ABTS radical scavenging activity increased from 27.23 to 233.04 μg TE g-1 by increased ascorbic acid levels. Ascorbic acid capsules were used in soft candy processing against free ascorbic acid and it was found that 47.9% ascorbic acid loss was detected for control sample at the 24-day storage while the ascorbic acid loss was approximately 25% for yeast microcapsules. It was concluded that yeast cells are capable of preserving ascorbic acid stability during storage and yeast cells can be used effectively and safely for the manufacturing of the ascorbic acid microcapsules. © 2024 Society of Chemical Industry.

Study of the Effect of Preparation and Formulation Factors on the Stability of Vitamin C Microencapsulated by Solvent-Evaporation Method

This research studied the effect of formulation and processing variables on the stability of vitamin C or Ascorbic Acid (AA) encapsulated in Eudragit RS100 microparticles prepared using a solvent evaporation technique. Microparticles ranged in size from 60 to 102 μm and encapsulation efficiencies between 25% and 44% were obtained. Microencapsulation significantly enhanced the stability of AA compared to the free AA in solution. AA shelf life was extended up to 23 days. Increasing AA concentration and using sucrose or Tween 80 in the outer phase further enhanced AA stability. The results suggest that microencapsulation method under the investigated conditions is a promising approach for protecting AA from degradation in aqueous solutions.

Cytotoxic and Antioxidative Effects of Geranium Oil and Ascorbic Acid Coloaded in Niosomes against MCF-7 Breast Cancer Cells.

Geranium oil (GO) has antiproliferative, antiangiogenic, and anti-inflammatory properties. Ascorbic acid (AA) is reported to inhibit the formation of reactive oxygen species, sensitize cancer cells, and induce apoptosis. In this context, AA, GO, and AA-GO were loaded into niosomal nanovesicles to ameliorate the physicochemical properties of GO and improve its cytotoxic effects using the thin-film hydration technique. The prepared nanovesicles had a spherical shape with average diameters ranging from 200 to 300 nm and exhibited outstanding surface negative charges, high entrapment efficiencies, and a controlled sustained release over 72 h. Entrapping AA and GO in niosomes resulted in a lower IC50 value than free AA and GO when tested on MCF-7 breast cancer cells. In addition, flow cytometry analysis showed higher apoptotic cells in the late apoptotic stage upon treating the MCF-7 breast cancer cells with AA-GO niosomal vesicles compared to treatments with free AA, free GO, and AA or GO loaded into niosomal nanovesicles. Assessing the antioxidant effect of the free drugs and loaded niosomal nanovesicles showed enhanced antioxidant activity of AA-GO niosomal vesicles. These findings suggest the AA-GO niosomal vesicles as a potential treatment strategy against breast cancer, possibly through scavenging free radicals.

Effects of blue light on physiological and biochemical changes in germinating cabbage sprouts

Sprouts as a natural food have been commonly consumed in different cultures, which are richer in health-promoting compounds than their mature counterparts. The purpose of this study was to investigate the effects of blue light on physiological and biochemical changes including sprout length, respiratory rate, free amino acids, ascorbic acid, glucosinolates, isothiocyanates and myrosinase activity in germinating cabbage sprouts. Furthermore, their correlation analysis was conducted to elucidate their changing patterns during germination and relationships with each other. The respiratory rate, free amino acids and ascorbic acid content were greatly enhanced by blue light compared to the darkness. Blue light could better retain glucosinolate content in cabbage sprouts than the darkness. More isothiocyanates formation was observed from cabbage sprouts under blue light, which was a result of the promoted myrosinase activity and higher glucosinolate content. These results indicate that blue light has selectively improved the nutritional compounds in germinated cabbage sprouts.

Physico-chemical Properties and Biological Activities of Thyme (Thymus vulgaris L.) Seed and Leaf Oil Extracts

Background: Thyme (Thymus vulgaris L., Lamiaceae), a medicinal plant with several therapeutic properties. This plant, native to Mediterranean regions, is commonly used as a culinary herb and with a long history of use for various medicinal purposes. Objective: The present study was aimed to examine the physicochemical properties, biological activities including antioxidant and antimicrobial activities of oil extracted from seeds and leaves of common thyme grown in Eastern Ethiopia. Methods: The oil extraction was done using petroleum ether as a solvent. Then, oil quality assessment was done based on the determination of oil content, specific gravity, acid value, percent free fatty acid, peroxide value, ascorbic acid, and free radical scavenging activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydrogen peroxide. The Biological activity was investigated based on antioxidant and antimicrobial activities. The antimicrobial activity was tested using disc diffusion and broth dilution methods. Results: The result of physicochemical properties of T. vulgaris seed oils demonstrated significantly higher oil content (14.75%), specific gravity (0.70±0.50), and peroxide value (1.90±0.14). The antioxidant activities of leaf oil extract presented significantly higher DPPH (22.30±1.27%). The stronger antibacterial activity with maximum zone of inhibition (15.67mm), minimum inhibitory concentration MIC (0.09µg/ml) and minimum bactericidal concentration MBC (0.18µg/ml) were was recorded for leaf oil against S. aureus. The strongest antifungal activity with maximum zone of inhibition (15.33±0.50mm) MIC (0.06 µg/ml), and minimum fungicidal concentration MFC (0.125 µg/ml) against A. niger. Conclusion: The result indicates that leaf oil has stronger antioxidant and antimicrobial potential than seed oil extract.

Synthesis and In Vitro Characterization of Ascorbyl Palmitate-Loaded Solid Lipid Nanoparticles.

Antitumor applications of ascorbic acid (AA) and its oxidized form dehydroascorbic acid (DHA) can be quite challenging due to their instability and sensitivity to degradation in aqueous media. To overcome this obstacle, we have synthesized solid lipid nanoparticles loaded with ascorbyl palmitate (SLN-AP) with variations in proportions of the polymer Pluronic F-68. SLNs were synthesized using the hot homogenization method, characterized by measuring the particle size, polydispersity, zeta potential and visualized by TEM. To investigate the cellular uptake of the SLN, we have incorporated coumarin-6 into the same SLN formulation and followed their successful uptake for 48 h. We have tested the cytotoxicity of the SLN formulations and free ascorbate forms, AA and DHA, on HEK 293 and U2OS cell lines by MTT assay. The SLN-AP in both formulations have a cytotoxic effect at lower concentrations when compared to ascorbate applied the form of AA or DHA. Better selectivity for targeting tumor cell line was observed with 3% Pluronic F-68. The antioxidative effect of the SLN-AP was observed as early as 1 h after the treatment with a small dose of ascorbate applied (5 µM). SLN-AP formulation with 3% Pluronic F-68 needs to be further optimized as an ascorbate carrier due to its intrinsic cytotoxicity.

PEGylated Chitosan Nanoparticles Encapsulating Ascorbic Acid and Oxaliplatin Exhibit Dramatic Apoptotic Effects against Breast Cancer Cells.

This study aims to design a pH-responsive dual-loaded nanosystem based on PEGylated chitosan nanoparticles loaded with ascorbic acid (AA) and oxaliplatin (OX) for the effective treatment of breast cancer. In this regard, non-PEGylated and PEGylated chitosan nanoparticles (CS NPs) loaded with either ascorbic acid (AA), oxaliplatin (OX), or dual-loaded with AA-OX were fabricated using the ionotropic gelation method. The hydrodynamic diameters of the fabricated AA/CS NPs, OX/CS NPs, and AA-OX/CS NPs were 157.20 ± 2.40, 188.10 ± 9.70, and 261.10 ± 9.19 nm, respectively. While the hydrodynamic diameters of the designed AA/PEG-CS NPs, OX/PEG-CS NPs, and AA-OX/PEG-CS NPs were 152.20 ± 2.40, 156.60 ± 4.82, and 176.00 ± 4.21 nm, respectively. The ζ-potential of the prepared nanoparticles demonstrated high positive surface charges of +22.02 ± 1.50, +22.58 ± 1.85 and +40.4 ± 2.71 mV for AA/CS NPs, OX/CS NPs, and AA-OX/CS NPs, respectively. The ζ-potential of the PEGylated CS NPs was reduced owing to the shielding of the positive charges by the PEG chains. Additionally, all the prepared nanoparticles exhibited high entrapment efficiencies (EE%) and spherical-shaped morphology. The chemical features of the prepared nanoparticles were investigated using Fourier transform infrared (FTIR) spectroscopy. Release studies showed the capability of the prepared non-PEGylated and PEGylated chitosan NPs to release their cargo in the acidic environment of cancer tissue (pH 5.5). Furthermore, the AA/CS NPs, AA/PEG-CS NPs, OX/CS NPs, OX/PEG-CS NPs, AA-OX/CS NPs and AA-OX/PEG-CS NPs exhibited remarkable cytotoxic activities against breast adenocarcinoma (MCF-7) cells with IC50 values of 44.87 ± 11.49, 23.3 ± 3.73, 23.88 ± 6.29, 17.98 ± 3.99, 18.69 ± 2.22, and 7.5 ± 0.69 µg/mL, respectively; as compared to free AA and OX (IC50 of 150.80 ± 26.50 and 147.70 ± 63.91 µg/mL, respectively). Additionally, treatment of MCF-7 cells with IC50 concentrations of AA, AA/CS NPs, AA/PEG-CS NPs, OX, OX/CS NPs, OX/PEG-CS NPs, AA-OX/CS NPs or AA-OX/PEG-CS NPs increased the percentages of early apoptotic cells to 5.28%, 9.53%, 11.20%, 5.27%, 13.80%, 8.43%, 2.32%, and 10.10%, respectively, and increased the percentages of late apoptotic cells to 0.98%, 0.37%, 2.41%, 2.06%, 0.97%, 9.66%, 56%, and 81.50%, respectively. These results clearly indicate that PEGylation enhances the apoptotic effect of AA and OX alone, in addition to potentiating the apoptotic effect of AA and OX when combined on MCF-7 cells. In conclusion, PEGylated chitosan nanoparticles encapsulating AA, OX, or AA and OX represent an effective formula for induction of apoptosis in MCF-7 cells.

Effect of Osmo Dehydration on Quality Attributes of Bilimbi (Averroha bilimbi) Fruits

Background: Bilimbi is a profusely bearing tree and majority of fruits produced are wasted due to lack of proper preservation methods. Osmo-dehydration studies on quality attributes of bilimbi (Averroha bilimbi) was conducted with the objective to standardize the process variables for osmodehydrated bilimbi and to assess the retention of bioactive compounds. Methods: Harvested mature bilimbi fruits of uniform size were washed, surface dried, pricked and blanched in hot water for one minute. Blanched fruits were subjected to osmotic treatment, with sucrose solution of 40, 60 and 80°B for 60, 120 and 180 minutes. The osmodehydrated bilimbi fruits were analyzed for mass transfer, biochemical and sensory qualities. Best treatments were stored for four months in the room temperature. Result: Mass transfer characters viz., solid gain, water loss, percentage weight reduction, yield and biochemical parameters such as reducing sugar and total sugar increased with increase in osmotic concentration and immersion time whereas free acids, ascorbic acid and antioxidant activity were decreased. The osmotic treatment of 80°B for 180 minutes recorded the highest value for solid gain (5.10%), water loss (16.72%), weight reduction (22.57%), ratio of water loss to solid gain (3.25%) and yield (21.13%) which exhibited superior sensory scores for taste (8.43), flavor (8.27), texture (8.46) and overall acceptability (8.43). The best three treatments selected based on sensory analysis were subjected to storage stability studies under room temperature. Osmodehydrated bilimbi obtained highest sensory score at the end of storage.

Assessing Nutritional Quality and Shelf life of Broccoli Cultivars

Inadequate knowledge on the nutritional and shelf life of broccoli render growers and consumers to poorly utilize this vegetable. To disseminate proper information on nutrition and storage it’s imperative to determine the nutrient content and shelf life of the modern cultivated broccoli cultivars. In this regard, five broccoli cultivars viz. Green Magic, Green Giant, Top Green, Early Green and Green Imported were evaluated to determine the nutritional and shelf life quality. A factorial Completely Randomized Design (CRD) with three replicates was used for experimentation. Data were collected on different vitamin, minerals and storage conditions (temperature, packaging). Collected data were statistically analyzed with the help of computer program MSTATC. Outcomes noted that, under fresh condition highest free ascorbic acid content (49.11mg/100g) was recorded in Green Magic. Green Giant had the maximum amount (1.07 mg/100gm) of b-carotene, reducing sugar (4.10 g/100g) and non-reducing sugar (1.53 g/100g). Green Imported had the most content of iron (162.71 ppm), calcium (0.85%) and magnesium (0.33%); while most amount of phosphorus (0.24%) was noted in Green Magic. The peak amount of potassium (0.99 %) and magnesium (0.33%) was found in Green Giant. The longest shelf life was obtained from Green Magic at 4°C (21.83 days) under polyethylene packaging condition. Hence it was noted that, shelf life and temperature had a vice versa relationship.

Preparation of fluorescent polydopamine nanoparticles regulated by CoOOH nanosheets for detection of alkaline phosphatase activity

Alkaline phosphatase (ALP) is an important enzyme which is widely distributed in organisms and participate in the vital process of dephosphorylation, often serve as a common biomarker for clinical diagnosis and treatment of human diseases. Herein, we reported a novel and simple strategy for the preparation of polydopamine nanoparticles (PDANPs) by employing CoOOH nanosheets as an oxidant. In the presence of CoOOH nanosheets, dopamine is easy to be oxidized and self-polymerize into fluorescent PDANPs. By employing the synthesized PDANPs as an effective fluorescence indicator, a fluorescence biosensor was established for label-free and sensitive determination of ALP activity based on the redox reaction between CoOOH nanosheets and the ALP hydrolysis product ascorbic acid (AA), and the dependence of CoOOH nanosheets concentration for formation of PDANPs. In the presence of ALP, the substrate ascorbic acid 2-phosphate (Asc-2P) was catalytically hydrolyzed and released free ascorbic acid, which could in situ reduction of Co(III) of CoOOH to Co(II) ions, resulting in the suppression of oxidation ability of CoOOH nanosheets, thus preventing the synthesis of fluorescent PDA. Therefore, the activity of ALP can be feasibly detected according to the changes of fluorescence peak at 490 nm of PDANPs. The sensor displays a linear range from 0.5 U/L to 300 U/L with a detection limit of 0.1 U/L. Moreover, the developed strategy exhibits good selectivity over other potential interference existing in human serum sample. The synthesis process of fluorescence PDANPs was facile and cost-effective, the proposed convenient and label-free fluorescence PDANPs detection platform shows potential applications in clinical diagnosis and provides a new paradigm for biological analysis.

Selenium yeast promoted the Se accumulation, nutrient quality and antioxidant system of cabbage (Brassica oleracea var. capitata L.)

ABSTRACT The application of Se yeast as a Se source to cultivate Se-rich cabbage has a significant effect on cabbage growth and quality indices. Results showed that total plant weight, head weight, and head size in cabbage were notably increased by 48.4%, 88.3%, and 25.4% under 16 mg/kg Se yeast treatment, respectively. Compare with the control, a high proportion of 3874% of Se accumulation in cabbage head was also detected in 16 mg/kg Se yeast treatment. Selenocystine (SeCys2) and Methyl-selenocysteine (MeSeCys) were the main Se speciations in the cabbage head. Application of 8 mg/kg Se yeast improved cabbage quality and antioxidant system indices, including free amino acid, soluble sugar, ascorbic acid, phenolic acid, glucosinolates, and SOD activity, which had 81.6%, 46.5%, 34.9%, 12.3%, 44.8%, 25.2% higher than that of the control, respectively. In summary, considering 8 mg/kg Se yeast as the appropriate level of Se enrichment during cabbage cultivation. These findings enhanced our understanding of the effects of Se yeast on the growth and quality of cabbage and provided new insights into Se-enrichment vegetable cultivation.

MoSx-Co₃O₄ Nanocomposite for Selective Determination of Ascorbic Acid.

Designing a nanocomposite with sensitive and selective determination of ascorbic acid is challenging task. It is possible through the exploitation of attractive features of nanoscience and nanotechnology for the synthesis of nanostructured materials. Herein, we report the decoration of nanoparticle of MoSx on the surface of Co₃O₄ nanowires by hydrothermal method. The MoSx nanoparticles shared the large surface on the Co₃O₄ nanowires, thus it supported in the development enzyme free ascorbic acid sensor. Non-enzymatic sensor based on MoSx-Co₃O₄ composite was found very selective for the determination of ascorbic acid (AA) in phosphate buffer solution of pH 7.4. The MoSx-Co₃O₄ nanocomposite was used to modify the glassy carbon electrode to measure AA from variety of practical samples. The MoSx-Co₃O₄ nanocomposite was used to modify the glassy carbon electrode and it has shown the attractive analytical features such as a low working potential +0.3 V, linear range of concentration from 100-7000 μM, low limit of detection 14 μM, and low limit of quantification (LOQ) of 42 μM. The developed sensor is highly selective and stable. Importantly, it was applied successfully for the practical applications such as detection of AA from grapefruit, tomato and lemon juice. The excellent electrochemical properties of fabricated MoSx-Co₃O₄ nanocomposite can be attributed to the increasing electro active surface area of MoSx. The presented nanocomposite is earth abundant, environment friendly and inexpensive and it holds promising features for the selective and sensitive determination of AA from practical applications. The nanocomposite can be capitalized into the wide range of biomedical applications.

Solar Reduced Graphene Oxide Based Enzyme Free Ascorbic Acid Sensor

In this research work, an electrochemical sensor has been prepared for the detection of ascorbic acid (Vit C) using a low cost and highly conductive solar radiation reduced graphene oxide (SRGO). The SRGO has been prepared using naturally available solar light for the reduction of graphene oxide. Various material characterization techniques have recognized SRGO for its morphology and conductivity. A detailed electrochemical study has been performed to test the applicability of SRGO for ascorbic acid sensing. SRGO modified electrode shows a quick response time (∼2s) and ascorbic acid was detected over a narrow linear range of 20μM to 360 μM. The developed sensor also shows a high sensitivity of 114 μAmmol -1 cm -2 and a lower limit of detection 56 (μM) for the ascorbic acid sensor. These results indicate that SRGO could be applied for the electrochemical study of vitamin C in food and vegetable samples.

The Vitamin C Analogue 2-O-β-D-Glucopyranosyl-L-ascorbic Acid in Rhizomes, Stems and Leaves of Lycium barbarum.

Awareness of health benefits of goji berries coming from their bioactive compounds, mostly antioxidants like ascorbic acid, has grown. Recently, an ascorbic acid analogue from goji berries, the 2-O-β-D-glucopyranosyl-L-ascorbic acid has been reported. In rats, the analogue is absorbed intact and in the form of free vitamin C and consequently has been proposed as a provitamin C. Synthesis of the analogue is demanding and laborious and therefore reliable natural sources are searched. Knowledge concerning the analogue's occurrence in other parts of goji plant is lacking. The aim of this study was to evaluate the contents of 2-O-β-D-glucopyranosyl-L-ascorbic acid in rhizomes, stems and leaves from Lycium barbarum. Rhizomes, stems and leaveswere extracted and the content of 2-O-β-D-glucopyranosyl-L-ascorbic acid and non glucosylated, free ascorbic acid was determined by HPLC-DAD. 2-O-β-D-glucopyranosyl-L-ascorbic acid was found in all goji plant tissues investigated. Based on dry weight, 3.34 mg/100 g were found in the leaves, 4.05 mg/100 g in the stems and up to 12.6 mg/100 g in the rhizomes. Nevertheless, the analogue content in goji berries is much higher (40 to 280 mg/100 g dry weight). The present study confirmed the presence of 2-O-β-D-glucopyranosyl-L-ascorbic acid in rhizomes, stems and leaves of Lycium barbarum. However, their content compared to goji berries is considerably lower.

Effect of sodium ascorbyl phosphate on osteoblast viability and differentiation.

Sodium ascorbyl phosphate (SAP) is a hydrophilic and stable L-ascorbic acid derivative, being converted by the cell phosphatases into free ascorbic acid (AA), which allows its sustained release in the medium. AA participates in the maintenance and healing of the periodontium. It presents a regulatory role of the osteoblastic activity, stimulating the deposition of collagen extracellular matrix followed by the induction of genes associated with the osteoblastic phenotype. It also acts in the elimination of reactive oxygen species, abundantly produced by defense cells in periodontal disease. The aim of this study was to evaluate the effect of SAP on osteoblast viability and differentiation. Mouse preosteoblastic cells of the MC3T3-E1 strain were used. Cell viability was assessed by the trypan blue dye exclusion assay and the expression of genes related to osteoblast differentiation by quantitative PCR. Collagen I secretion was evaluated by ELISA, and mineralized matrix formation was assayed by Alizarin red S staining. The results showed that SAP at concentrations from 50 to 500µmol/L does not influence preosteoblast cell viability, but stimulates their differentiation, observed by the induction of RUNX2, COL1A1, and BGLAP2; by the higher secreted levels of collagen I; and also by the increase in the mineralization of the extracellular matrix in cells exposed to this agent at 200 or 400µmol/L, compared with those not exposed. By its stability and capacity to induce preosteoblastic cell differentiation, our results indicate that the incorporation of SAP into local release devices, membranes/scaffolds or biomaterials, could favor bone tissue formation and therefore periodontal healing.

The research determines appropriate parameters in the synthesis process of syringic acid grafted chitooligosaccharides

Introduction: The aim of this study is to determine appropriate parameters in the synthesis of syringic acid onto chitooligosaccharides (COSs) with an ascorbic acid/hydrogen peroxide redox pair in order to obtain the derivative with the highest grafting degree.
 Methods: In this study, syringic acid grafted COSs, catalysed by an ascorbic acid/hydrogen peroxide redox pair were investigated. The synthesis conditions were investigated, including the mass ratio between syringic acid and COSs, pH, temperature and synthesis time. Characteristics of the derivative were evaluated by Thin Layer Chromatography (TLC), Ultraviolet-Visible (UV-vis) and Fourier Transform Infrared (FT-IR) spectroscopy. The activities of COSs and derivative were evaluated by antimicrobial ability.
 Results: The results showed, that the best conditions for the synthesis were the mass ratio between syringic acid and COSs at 0.5:1, pH 5, temperature 27oC, for 6 hours with grafting degree at 32%. The TLC assay showed, that free ascorbic acid and syringic acid are not present in the product. The UV-vis and FT-IR data confirmed, that syringic acid was successfully conjugated onto COSs. Furthermore, the antibacterial assay showed that syringic acid grafted onto COSs had minimum inhibitory concentration against foodborne pathogenic bacteria at 1%.
 Conclusion: The syringic acid onto chitooligosaccharides were successfully synthesized by free radical mediated grafting method with an ascorbic acid/hydrogen peroxide redox pair. The grafting degree of syringic acid onto COSs was greatly affected by many factors, including COSs, syringic acid, pH, as well as temperature and time of reaction. Moreover, the new derivative showed enhanced antibacterial capabilities, as compare to free COSs.

Ascorbic acid encapsulated into negatively charged liposomes exhibits increased skin permeation, retention and enhances collagen synthesis by fibroblasts

Ascorbic acid (AA) is widely used in cosmetic formulations due to its antioxidant property and ability to increase collagen synthesis. Here, we encapsulated AA in vesicles with different lipid compositions. Negative liposome charge favored AA skin retention, with accumulation of 37 ± 12 and 74 ± 23 μg/cm2 in the epidermis and dermis, respectively, after 6 hours. Drug flux was influenced by the formulation composition, and both the presence of cholesterol and the liposomes surface charge were able to increase the amount of AA crossing the skin. The formulation was stable for at least 30 days and promoted a 7-fold increase in flux compared to free AA. Additionally, liposomes were able to interact better with keratinocytes and fibroblasts membranes. In vitro efficacy studies demonstrated that associating AA to these liposomes resulted in increased effectiveness of type I collagen synthesis by fibroblasts and regeneration of UVA-induced damage in keratinocytes. Our results demonstrate the applicability of AA-negatively charged liposomes in promoting AA cutaneous permeation and increasing the retention and flux of this molecule in the skin. This formulation also increased AA stability and effectiveness, opening new perspectives for its application in view of reducing certain skin ageing outcomes.

Fluorometric turn-on determination of the activity of alkaline phosphatase by using WS2 quantum dots and enzymatic cleavage of ascorbic acid 2-phosphate.

A method is described for the determination of the activity of alkaline phosphatase (ALP). It is based on the reversible modulation of the fluorescence of WS2 quantum dots (QDs). The fluorescence of the QDs is quenched by Cr(VI) but restored by free ascorbic acid (AA). The detection scheme relies on the fact that ALP hydrolyzes the substrate ascorbic acid 2-phosphate to produce AA, and that enzymatically generated AA can restore the fluorescence of the QDs. The signal (best measured at excitation/emission peak wavelengths of 365/440 nm) increases linearly in the 0.5 to 10U·L-1 ALP activity range, with a detection limit of 0.2U·L-1. The method was applied to the determination of ALP activity in human serum samples and demonstrated satisfactory results. Graphical abstract The fluorescence of chromate-loaded tungsten disulfide quantum dots (QDs) is quenched but restored after reaction with ascorbic acid that is formed by the catalytic action of alkaline phosphatase (ALP) on ascorbic acid 2-phosphate (AAP). The increase in fluorescence can be related to the activity of ALP.

THE ROLE OF LIPOSOME -ENCAPSULATED ASCORBIC ACID ON HEMOGLOBIN DAMAGE BY GAMMA IRRADIATION.

Ionizing radiation causes serious damage in a biological system. Some drugs and antioxidants are used to prevent such damage. In vitro we study the effect of free ascorbic acid(AA) and liposome encapsulation ascorbic acid (LEAA) to prevent damage induced by gamma irridiatin on rats blood . Liposomes prepared by thin film hydration method . Size ,and poly dispersed index (PDI) were analyzed by dynamic light scattering before and after encapsulation AA ,and shape was analyzed by transmission electron microscopy(TEM). Percentage encapsulation efficiency (EE%) of ascorbic acid was determined and IR study has been employed to reveal structure alteration in vesicles before and after encapsulation. two doses of free ascorbic acid ( 20 µg /ml ,40 µg /ml) were selected to be used for such purpose. Also the same doses were used encapsulated in liposomes . Our study were carried through UV-visible spectrum absorption spectrum , relative viscosity and conductivity measurement . The results show that EE% have a high encapsulation of vitamins C, there no detectable change is observed in size of liposome before and after encapsulation. The data obtained from UV-visible indicate that there is great change in the absorbance of sort band, and in the absorption A576/ A541 ratio in blood irradiated to 5 GY γ- irradiation by dose rate 62cGY/mint as compared with normal hemoglobin. The result indicated that ,the change decreases by increasing doses of free AA came close to normal hemoglobin and approaching more to normal in the case of liposome encapsulation ascorbic acid .

α-Tocopherol-ascorbic acid hybrid antioxidant based cationic amphiphile for gene delivery: Design, synthesis and transfection

Natural antioxidants and vitamins have potential to protect biological systems from peroxidative damage induced by peroxyl radicals, α-tocopherol (Vitamin E, lipid soluble) and ascorbic acid (vitamin C, water soluble), well known natural antioxidant molecules. In the present study we described the synthesis and biological evaluation of hybrid of these two natural antioxidants with each other via ammonium di-ethylether linker, Toc-As in gene delivery. Two control cationic lipids N14-As and Toc-NOH are designed in such a way that one is with ascorbic acid moiety and no tocopherol moiety; another is with tocopherol moiety and no ascorbic acid moiety respectively. All the three cationic lipids can form self-assembled aggregates. The antioxidant efficiencies of the three lipids were compared with free ascorbic acid. The cationic lipids (Toc-As, N14-As and Toc-NOH) were formulated individually with a well-known fusogenic co-lipid DOPE and characterization studies such as DNA binding, heparin displacement, size, charge, circular dichroism were performed. The biological characterization studies such as cell viability assay and in vitro transfection studies were carried out with the above formulations in HepG2, Neuro-2a, CHO andHEK-293T cell lines. The three formulations showed their transfection efficiencies with highest in Toc-As, moderate inN14-As and least in Toc-NOH. Interestingly, the transfection efficiency observed with the antioxidant based conjugated lipid Toc-As is found to be approximately two and half fold higher than the commercially available lipofectamine 2000 at 4:1 charge ratio in Hep G2 cell lines. In the other cell lines studied the efficiency of Toc-As is found to be either higher or similarly active compared to lipofectamine 2000. The physicochemical characterization results show that Toc-As lipid is showing maximum antioxidant potency, strong binding with pDNA, least size and optimal zeta potential. It is also found to be least toxic in all the cell lines studied especially in Neuro-2a cell lines when compared to other two lipids. In summary, the designed antioxidant lipid can be exploited as a delivering system for treating ROS related diseases such as malignancy, brain stroke, etc.