ChapterPDF Available
Chapter 1
Vitamin C: Sources, Functions, Sensing and Analysis
Sudha J. Devaki and Reshma Lali Raveendran
Additional information is available at the end of the chapter
http://dx.doi.org/10.5772/intechopen.70162
Abstract
Vitamin C is a water-soluble compound found in living organisms. It is an essential nutri-
ent for various metabolism in our body and also serves as a reagent for the prepara-
tion of many materials in the pharmaceutical and food industry. In this perspective, this
chapter can develop interest and curiosity among all practicing scientists and technolo-
gists by expounding the details of its sources, chemistry, multifunctional properties and
applications.
Keywords: vitamin C, biomarker, antioxidant, sensors
1. Introduction
Vitamin C also known as ascorbic acid (AA) is an essential nutrient in many multicellular organ-
isms, especially in humans. Ascorbic acid is a water-soluble vitamin and is found in variable
quantities in fruits and vegetables and organ meats (e.g. liver and kidney). Deciency of vitamin
C causes scurvy, widespread connective tissue weakness and capillary fragility. Among chem-
ists, it is used as a reagent for the preparation of ne chemicals, enzymatic reagent and nanoma-
terials. Consequently, the detection and quantication of ascorbic acid in food samples, products
and nutraceuticals is receiving overwhelming importance among researchers, medical practitio-
ners and also in the pharmaceutical and food industry. Figure 1 shows the schematic representa-
tion of the sources and multifunctional applications of vitamin C in the metabolism of our body.
2. Sources
Vitamin C (Figure 2) is abundantly available in many natural sources, including fresh fruits
and vegetables. The richest sources of ascorbic acid including Indian gooseberry, citrus fruits
© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
such as limes, oranges and lemons, tomatoes, potatoes, papaya, green and red peppers, kiwi-
fruit, strawberries and cantaloupes, green leafy vegetables such as broccoli, fortied cereals
and its juices are also rich sources of vitamin C.
Another source of vitamin C is animals. They usually synthesize their own vitamin C and are
highly concentrated in the liver part [1, 2]. Sources of vitamin C and its content are given in
Figure 3. Average daily recommended amounts of vitamin C for dierent ages are also given
in Table 1.
Figure 1. Sources and multifunctional role of vitamin C in metabolic processes in human body.
Figure 2. Structure of vitamin C.
Vitamin C4
Figure 3. Amount of vitamin C in dierent sources.
Infants
Age Adequate intake (AI) mg/day Upper intake level
(UL)
0–6 monthsa25 –
7–12 monthsb30 –
Children and adolescents
Age EARcRDId
mg/day mg/day mg/day
1–3 25 35 400
4–8 25 35 650
9–14 28 40 1200
14–18 28 40 1800
Adults
Men Women Both
Age EARcRDIdEARcRDId
mg/day mg/day mg/day mg/day mg/day
19–30 30 45 30 45 2000
31–50 30 45 30 45 2000
51–70 30 45 30 45 2000
>70 30 45 30 45 2000
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
5
3. Functions
Vitamin C plays an important role in many physiological processes in humans. It is needed
for the repair of tissues in all parts of the body. The important functions of vitamin C include
the formation of protein used to make skin, tendons, ligaments, and blood vessels for healing
wounds and forming scar tissue, for repairing and maintaining cartilage, bones, and teeth
and aid in the absorption of iron. It can also act as a reducing and capping agent for metal
nanoparticles.
3.1. As reducing and capping agent
Ascorbic acid acts as a reducing and capping agent for the synthesis of metal nanoparticles
such as silver, gold, copper, etc. Ascorbic acid molecules can cap or surround the particle
and prevent the uncontrolled growth of the particles to micron-sized dimensions. A study
by Khan et al., in 2016 reported the synthesis of copper nanoparticle by using ascorbic acid
as both the reducing agent [6]. Sun et al. reported in Journal of Materials Science in 2009 that
gold nanoparticles can be synthesised in reverse micelles without the addition or introduc-
tion of any other reducing or capping reagent [7]. In analytical methods in 2014, D’souza
et al. reported the use of AA-Au NPs as a colorimetric probe for detection of dichlorvos in
water and wheat samples. The inuence of AA concentration on the aggregation induced by
dichlorvos in AA-AuNPs (Figure 4) and the optical property of the AA-Au NPs was investi-
gated by UV-Vis spectroscopy [8].
Infants
Age Adequate intake (AI) mg/day Upper intake level
(UL)
Motherhood
Pregnancy Lactation Both
Age EARcRDIdEARcRDId
mg/day mg/day mg/day mg/day mg/day
14–18 38 55 58 80 2000
19–30 40 60 60 85 2000
31–50 40 60 60 85 2000
aCalculated as per the average intake of breast milk.
bCalculated on a body weight basis of infants.
cEstimated average requirement.
dRecommended dietary intake.
Table 1. Dietary intake of vitamin C [3–5].
Vitamin C6
3.2. Antioxidant activity
One of the important properties of vitamin C is its antioxidant activity. Antioxidant activity of
vitamin C helps to prevent certain diseases such as cancer, cardiovascular diseases, common
cold, age-related muscular degeneration and cataract.
3.3. In cancer treatment
Since 1970, it has been known that high dose of vitamin C has benecial eects on the sur-
vival time in patients with terminal cancer, which was reported by Cameron, Campbell, and
Pauling. Research is undergoing in detail for using vitamin C in cancer treatment [9–11]. One
of the studies suggests that pharmacologic doses of vitamin C might show promising eects
on the treatment of tumours [12]. Vitamin C can act as pro-oxidant and it can generate hydro-
gen peroxide [13, 14]. Administration of high dose of vitamin C gives long survival times for
patients with advanced cancers.
The continuing aack of DNA by unquenched reactive oxygen species is believed to cause
cancer. As a physiological antioxidant, ascorbic acid plays a role in the prevention of oxida-
tive damage to DNA, which is elevated in cells at sites of chronic inammation and in many
pre-neoplastic lesions. Most DNA damage is repaired metabolically; however, the frequency
of elevated steady-state levels of oxidized DNA bases is estimated to be sucient to cause
mutational events. The base damage product 8-hydroxy-2′-deoxyguanosine has been found
to be elevated in individuals with severe vitamin C deciency and to be reduced by supple-
mentation with vitamins C and E [15].
Figure 4. Analytical process for detecting dichlorvos using AA-Au NPs as a colorimetric probe [8].
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
7
Oxidative stress, arising as a result of an imbalance between free radical production and anti-
oxidant defences, causes damage to a wide range of molecular species including lipids, pro-
teins and nucleic acids. Oxidative stress caused by free radicals is shown in Figure 5. The best
way to ensure adequate intake of the antioxidant nutrients, such as vitamins C and E and
various kinds of minerals, is through a balanced diet consisting of 5–8 servings of fruits and
vegetables per day.
3.4. In cardiovascular diseases
The antioxidant property of vitamin C helps for the treatment of cardiovascular diseases.
Vitamin C has the capability for reducing monocyte adherence to the endothelium, improv-
ing endothelium-dependent nitric oxide production and vasodilation and reducing vascular
smooth-muscle-cell apoptosis, which prevents plaque instability in atherosclerosis [15]. The
oxidative damage including the oxidative modication of low-density lipoproteins is a major
cause of cardiovascular disease. The antioxidant property of vitamin C helps to reduce this to
a certain extent [16, 17].
3.5. In common cold
Pauling in 1970 suggested that vitamin C can be used for the treatment of common cold [18].
There are so many reports in Cochrane Database Syst. Review showing the use of prophylactic
Figure 5. Oxidative stress by free radicals.
Vitamin C8
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
9
radicals. Those reactions are likely to be of fundamental importance in all aerobic cells. This
reaction is the basis of most of the biological functions of ascorbic acid. The mechanism of free
radical action on DNA is shown in Figure 8.
Vitamin C also has role in protecting other vitamins (vitamin A and vitamin E) from the harm-
ful eects of oxidation. Vitamin C helps in protecting gums and retards ageing. It strengthens
the general physical condition by removing toxic metals from the body. Vitamin C reduces
the formation of cataract and hence useful in the treatment of glaucoma.
Figure 7. Antioxidant mechanism.
Figure 8. Mechanism of free radical action on DNA.
Vitamin C10
3.8. Synthesis of protein
Another important function of vitamin C is its role in the synthesis of protein. Vitamin C helps
in the synthesis of collagen. Collagen protects our skin from wrinkling and makes our skin
rm and strong. Collagen also protects and supports organs and other soft tissues. One of the
amino acids used to build collagen—hydroxyproline—is only synthesized when vitamin C is
available. Functions of vitamin C on skin.
3.9. Functions of vitamin C on skin
3.9.1. Photoprotection
Vitamin C reduces the damage caused by UV-light exposure. It cannot act as a sunscreen
since it cannot absorb UV light. But the antioxidant activity of vitamin C helps to protect UV
damage caused by free radicals [26]. In response to UV light, vitamin C transport proteins are
increased, suggesting an increased need for vitamin C uptake for adequate protection [27, 28].
Addition of keratinocytes on vitamin C reduces damages caused by UV light and lipid peroxi-
dation, limits the release of pro-inammatory cytokines and protects against apoptosis [29].
Many studies have suggested that vitamin C consumption alone will not reduce the eect of
UV exposure; however, a combination of vitamin C and E eectively increases minimal ery-
themal dose (MED) (the lowest dose of ultraviolet radiation (UVR) that will produce a detect-
able erythema 24 hours after UVR exposure) and decreases erythema-induced blood ow
to damaged areas of skin [30]. Thus, interactions between the two antioxidant vitamins may
be necessary to achieve UV protection. The topical application of vitamin C also reduces the
eect of UV exposure and skin wrinkling and skin tumour [31]. Vitamin C reduced the num-
ber of sunburned cells, decreased erythema response and reduced DNA damage induced by
UV exposure [27]. The combination of antioxidant vitamins decreased the immunosuppres-
sive eects of UV exposure, increased MED and decreased cell damage [32, 33].
3.9.2. Wound healing
Vitamin C plays a key role in healing wound by the formation of collagen, connective tissue
[34–36]. The new tissue is rebuilt with the help of collagen framework. This function is sup-
ported by its co-factor vitamin C. Besides this, vitamin C performs as a strong antioxidant and
immune system modulator [37, 38].
3.10. Deciency of vitamin C
Deciency of vitamin C in humans causes a major disease called scurvy. The major signs
of the disease occur primarily in mesenchymal tissues. It leads to impaired wound healing;
oedema; haemorrhage (due to decient formation of intercellular substance) in the skin,
mucous membranes, internal organs, and muscles; and weakening of collagenous struc-
tures in bone, cartilage, teeth and connective tissues. Those who suer from scurvy have
swollen, bleeding gums with tooth loss. They also show lethargy, fatigue, rheumatic pains
in the legs, muscular atrophy and skin lesions, massive sheet hematomas in the thighs,
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
11
and ecchymoses and haemorrhages in many organs, including the intestines, sub-periosteal
tissues and eyes. All these features are accompanied by psychological changes: hysteria,
hypochondria and depression. In children, the syndrome is called Moeller-Barlow disease;
it is seen in non-breastfed infants usually at about 6 months of age and is characterized
by widening of bone-cartilage boundaries, stressed epiphyseal cartilage of the extremities,
severe joint pain and frequently, anaemia and fever. Children having this disease present
with a limp or inability to walk, tenderness of the lower limbs, bleeding of the gums and
petechial haemorrhages.
4. Detection and sensing
Many analytical techniques are used for the determination of vitamin C in dierent matrices,
such as titrimetric [39], uorimetric [40], spectrophotometric [41], high-performance liquid
chromatography [42], enzymatic [43], kinetic [44, 45] and electrochemical, etc.
4.1. High-performance liquid chromatography (HPLC)
High-performance liquid chromatography (HPLC) methods are preferred earlier because
they are faster and more eective than spectrophotometric, titration or enzymatic methods,
and they do not usually need derivatization [46]. In pharmaceutical and cosmetic industries,
HPLC is used, which is considered as a sensitive and selective method.
Detection of vitamin C through HPLC has been done by many groups. Racz et al. in 1990
reported that HPLC used the HPLC method for the determination of ascorbic acid in fruits
and vegetables. The method has been used to deep-frozen raspberry cream analysis together
with three commonly used chemical methods of vitamin C analysis. The HPLC method has
been compared with the chemical methods from several aspects, and the superiority of HPLC
method has been concluded [47].
Snezana et al. reported the HPLC method for the determination of vitamin C in pharmaceu-
tical samples in Tropical Journal of Pharmaceutical Research in 2011 [48]. The simplicity of this
low-cost, rapid technique and its high specicity to ascorbic acid, even in the presence of a
variety of excipients, demonstrate that this HPLC method would be particularly suitable for
the determination of ascorbic acid (Figure 9). It can be used in pharmaceutical/veterinary
formulations without prior sample preparation.
Another work carried out by Franco et al., which was to optimize and validate a new analytic
strategy for the determination of vitamin C in strawberries by UV–HPLC [49].
For the accurate and reliable measurement of ascorbic acid and dehydroascorbic acid, HPLC
can be used in combination with electrochemical or ultraviolet detection. Line and Hoer
have reported a method for the determination of vitamin C in plasma. It can be analysed
by HPLC in connection with electrochemical or ultraviolet light detection. Electrochemical
HPLC has advantages over UV-HPLC for plasma total vitamin C analysis [50].
Vitamin C12
4.2. Spectrophotometric method
Among many analytical methods, spectrophotometric methods are very simple and low-cost.
Several studies used the spectrophotometric method for the determination of ascorbic acid.
Güçlü et al. [51] have proposed a spectrophotometric method based on ascorbic acid oxida-
tion to dehydroascorbic acid, by using the Cu(II)-neocuproine complex, which is reduced to
Cu(I)-bis(neocuproine), the absorbance of the laer being determined at 450 nm. Other opti-
cal methods for vitamin C estimation include spectrophotometrical determination of iodine
reacted with ascorbic acid [52] and chemiluminescence [53].
A sensitive, simple and low-cost spectrophotometric method was introduced by Kobra and
Somayye in 2015. The present method was successfully applied to determine the ascorbic acid
in food and pharmaceutical samples. The samples were multivitamin tablet, eervescent tab-
let, vitamin C injection, natural orange juice, orange syrup powdered and commercial orange
liquid. The method is based on the reaction of AgNO3 with ascorbic acid in the presence of
polyvinyl pyrrolidone (PVP) and slightly basic medium to prepare silver nanoparticles [54].
Kapur et al. in 2015 reported a method that is based on the oxidation of ascorbic acid to
dehydroascorbic acid by bromine water in the presence of acetic acid. In this method, the
total ascorbic acid (ascorbic acid + dehydroascorbic acid) has been determined in 21 dierent
samples of fruits and vegetables by the spectrophotometric method [55]. Mohammed and
Hazim in 2016 reported a UV-spectrophotometric method for the determination of ascorbic
acid in fruits and vegetables from hill region with 2,4-dinitrophenylhydrazine [56].
A new sensitive colorimetric method for the determination of ascorbic acid tablet in aqueous
solution was reported by Ahmed and Mohamed in 2013. The method is based on the forma-
tion of coloured azo dye by diazotization of 2,4-dichloroaniline, followed by azo-coupling
reaction between the resulting product and ascorbic acid [57].
Figure 9. HPLC plot of ascorbic acid detection.
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
13
Figure 10. Cyclic voltammogram of electrochemical sensing of ascorbic acid using a polyaniline-modied platinum
electrode [70].
4.3. Electrochemical sensing
Electrochemical sensing methods are more widely applied as they are simple, sensitive and
moderate methods. Ascorbic acid (AA), dopamine and catecholamine are important neu-
rotransmiers in the human body. Hence, the low-level detection of ascorbic acid is very
important. All the methods mentioned above involve complicated pretreatment techniques
and expensive instruments. Hence, researchers have developed a more simple, sensitive
and accurate electrochemical method for the detection of ascorbic acid. Several studies have
reported the electrochemical sensing methods for detection of ascorbic acid. Aempts to sim-
plify such methods have resulted in the development of new methods such as the nickel
hexacyanoferrate lm-modied aluminium electrode [58] and graphite epoxy electrode [59].
These methods use specic and modied working electrode systems that are complicated
[60]. These electrochemical methods are widely used to monitor AA metabolites in vivo or
in vitro [61, 62]. For example, batch injection amperometric methods can achieve a detection
limit as low as 450 mg/L [63]. The metallic nickel electrode (2610–6 M), chemiluminometric
ow method (5l M) [64], carbon paste mixed electrode (1.08610–5 M) [65], polyviologen-mod-
ied technique (0.38l M) [66] and NiGCNF plating-modied electrode (2610–6 M) [67] achieve
very sensitive detection ranges.
Suw et al. in 2004 developed a stripping voltammetric technique that manifests faster response,
more cost-eective and sensitive preconcentration techniques, which was used along with a
simpler glassy carbon electrode [68]. In this method, low ascorbic acid concentrations were
detected by the square wave stripping voltammetry and a glassy carbon electrode. The lower
detection limit reported as 0.30l g/L (S/N = 3). This method can be used to detect biological
materials, pharmaceuticals, food and drugs.
Many reports are there for the simultaneous electrochemical detection of ascorbic acid in the
presence of dopamine and uric acid on the glassy carbon electrode. From our own group,
we have synthesized electrically conducting poly (3,4-ethylenedioxythiophene) nanospindles
(PEDOTSs) and used for the electrochemical sensing of ascorbic acid [69] (Figure 10).
Vitamin C14
In another study, our group developed a low-cost electrochemical sensor based on a platinum
electrode for ascorbic acid conductive polyaniline-based composite. This unique low-cost and
user-friendly sensor was validated for the nanomolar detection of AA. The lower detection
limit for AA was observed at 0.1 nm. The aqueous PPICS/Pt electrode could serve as a pro-
spective low-cost and ecient electrochemical sensor and provide promising and outstand-
ing contributions to the food, beverage and medical industries [70].
Electrochemical methods have aracted much aention from clinical diagnostic perspectives
because of their easy operation, low cost, rapid response, high sensitivity and good selectivity.
5. Conclusion
Vitamin C plays a pivotal role in body-building process and in disease prevention. The
various functions of vitamin C, including the antioxidant activity, formation of protein,
tendons, ligaments and blood vessels, for healing wounds and form scar tissue, for repair-
ing and maintaining cartilage, bone, and teeth, and aiding in the absorption of iron, were
discussed. This chapter will denitely benet the students, researchers and technologists
globally.
Author details
Sudha J. Devaki* and Reshma Lali Raveendran
*Address all correspondence to: sudhajd2001@yahoo.co.in
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary
Science and Technology (CSIR-NIIST), Thiruvananthapuram, India
References
[1] Food and Nutrition Board. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium,
and Carotenoids. Washington, DC: National Academy Press; 2000
[2] Nutrient Data Laboratory. USDA National Nutrient Database for Standard Reference,
Release 24 [Internet]. Available from hp://www.ars.usda.gov/ba/bhnrc/nd
[3] Commiee on Medical Aspects of Food Policy; 1991
[4] Food and Nutrition Board: Institute of Medicine; 2000
[5] Food and Agricultural Organization, World Health Organization; 2002
[6] Khan A, Rashid A, Younas R, Chong R. A chemical reduction approach to the synthesis
of copper nanoparticles. International Nano Leers. 2016;6:21-26.
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
15
[7] Sun K, Qiu J, Liu J, Miao Y. Preparation and characterization of gold nanoparticles using
ascorbic acid as reducing agent in reverse micelles. J Mater Sci. 2009;44:754
[8] D’souza SL, Pati RK, Kailasa SK. Ascorbic acid functionalized gold nanoparticles as a
probe for colorimetric and visual read-out determination of dichlorvos in environmental
samples. Analytical Methods. 2014;6:9007-9014
[9] Cameron E, Campbell A. The orthomolecular treatment of cancer. II. Clinical trial of
high-dose ascorbic acid supplements in advanced human cancer. Chem Biol Interact.
1974;9:285-315
[10] Cameron E, Pauling L. Supplemental ascorbate in the supportive treatment of cancer:
Prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A. 1976;
73:3685-9
[11] Cameron E, Pauling L. Supplemental ascorbate in the supportive treatment of cancer:
reevaluation of prolongation of survival times in terminal human cancer. Proc Natl Acad
Sci U S A. 1978;75:4538-42
[12] Chen Q, Espey MG, Sun AY, Pooput C, Kirk KL, Krishna MC. Pharmacologic doses of
ascorbate act as a prooxidant and decrease growth of aggressive tumor xenografts in
mice. Proceedings of the National Academy of Sciences of the United States of America.
2008;105:11105-11109
[13] Chen Q, Espey MG, Krishna MC, Mitchell JB, Corpe CP, Buener GR. Pharmacologic
ascorbic acid concentrations selectively kill cancer cells: Action as a pro-drug to deliver
hydrogen peroxide to tissues. Proceedings of the National Academy of Sciences of the
United States of America. 2005;102:13604-13609
[14] Chen Q, Espey MG, Sun AY, Lee JH, Krishna MC, Shacter E. Ascorbate in pharmacologic
concentrations selectively generates ascorbate radical and hydrogen peroxide in extra-
cellular uid in vivo. Proceedings of the National Academy of Sciences of the United
States of America. 2007;104:8749-8754
[15] Honarbakhsh S, Schachter M. Vitamins and cardiovascular disease. British Journal of
Nutrition. 2008;101:1113-1131
[16] Jacob RA, Sotoudeh G. Vitamin C function and status in chronic disease. Nutrition in
Clinical Care. 2002;5:66-74
[17] Willcox BJ, Curb JD, Rodriguez BL. Antioxidants in cardiovascular health and dis-
ease: Key lessons from epidemiologic studies. American Journal of Cardiology.
2008;101:75-86D
[18] Pauling L. The signicance of the evidence about ascorbic acid and the common cold.
Proceedings of the National Academy of Sciences of the United States of America.
1971;68:2678-2681
[19] Douglas RM, Hemilä H, Chalker E, Treacy B. Vitamin C for preventing and treating the
common cold. Cochrane Database Systematic Review. 2007;3:CD000980
Vitamin C16
[20] Johnston CS. The antihistamine action of ascorbic acid. Subcellular Biochemistry.
1996;25:189-213
[21] Evans JR, Lawrenson JG. Antioxidant vitamin and mineral supplements for slowing
the progression of age-related macular degeneration. Cochrane Database Systematic
Review. 2012;11:CD000254
[22] Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled,
clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and
zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Archives
of Ophthalmology. 2001;119:1417-1436
[23] The Age-Related Eye Disease Study 2 (AREDS2) Research Group. Lutein + zeaxan-
thin and omega-3 fay acids for age-related macular degeneration: The Age-Related
Eye Disease Study 2 (AREDS2) randomized clinical trial. Journal of American Medical
Association. 2013;309:2005-2015
[24] Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based
on antioxidant and health eects in humans. American Journal of Clinical Nutrition.
1999;69:1086-1107
[25] Rautiainen S, Lindblad BE, Morgenstern R, Wolk A. Vitamin C supplements and the
risk of age-related cataract: A population-based prospective cohort study in women.
American Journal of Clinical Nutrition. 2010;91(2):487-493
[26] Darr D, Combs S, Dunston S, Manning T, Pinnell S. Topical vitamin C protects por-
cine skin from ultraviolet radiation-induced damage. British Journal of Dermatology.
1992;127:247-253
[27] Steiling H, Longet K, Moodyclie A. Sodium-dependent vitamin C transporter iso-
forms in skin: Distribution, kinetics, and eect of UVB-induced oxidative stress. Radical
Biology and Medicine. 2007;43:752-762
[28] Kang JS, Kim HN, Jung da J. Regulation of UVB-induced IL-8 and MCP-1 production in
skin keratinocytes by increasing vitamin C uptake via the redistribution of SVCT-1 from
the cytosol to the membrane. Journal of Investigative Dermatology. 2007;127:698-706
[29] Tebbe B, Wu S, Geilen CC, Eberle J, Kodelja V, Orfanos CE. L-ascorbic acid inhibits
UVAinduced lipid peroxidation and secretion of IL-1alpha and IL-6 in cultured human
keratinocytes in vitro. Journal of Investigative Dermatology. 1997;108:302-306
[30] Eberlein-Konig B, Placzek M, Przybilla B. Protective eect against sunburn of combined
systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). Journal of the
American Academy of Dermatology. 1998;38:45-48
[31] Bisse DL, Chaerjee R, Hannon DP. Photoprotective eect of superoxide-scavenging
antioxidants against ultraviolet radiation-induced chronic skin damage in the hairless
mouse. Photodermatology, Photoimmunology & Photomedicine. 1990;7:56-62
[32] Lin FH, Lin JY, Gupta RD. Ferulic acid stabilizes a solution of vitamins C and E and dou-
bles its photoprotection of skin. Journal of Investigative Dermatology. 2005;125:826-832
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
17
[33] Lin JY, Selim MA, Shea CR. UV photoprotection by combination topical antioxi-
dants vitamin C and vitamin E. Journal of the American Academy of Dermatology.
2003;48:866-874
[34] Savini I, Catani MV, Rossi A, Duranti G, Melino G, Avigliano L. Characterization of
keratinocyte dierentiation induced by ascorbic acid: Protein kinase C involvement and
vitamin C homeostasis. Journal of Investigative Dermatology. 2002;118:372-379
[35] Boyce ST, Supp AP, Swope VB, Warden GD. Vitamin C regulates keratinocyte viabil-
ity, epidermal barrier, and basement membrane in vitro, and reduces wound contrac-
tion after grafting of cultured skin substitutes. Journal of Investigative Dermatology.
2002;118:565-572
[36] Ponec M, Weerheim A, Kempenaar J. The formation of competent barrier lipids in recon-
structed human epidermis requires the presence of vitamin C. Journal of Investigative
Dermatology. 1997;109:348-355
[37] Silverstein RJ, Landsman AS. The eects of a moderate and high dose of vitamin C on
wound healing in a controlled guinea pig model. Journal of Foot and Ankle Surgery.
1999;38:333-338
[38] Vaxman F, Olender S, Lambert A. Eect of pantothenic acid and ascorbic acid supple-
mentation on human skin wound healing process. A double-blind, prospective and ran-
domized trial. Journal of Surgical Research. 1995;27:158-166
[39] Verma KK, Jain A, Sahasrabuddhey B, Gupta K, Mishra S. Solid-phase extraction cleanup
for determining ascorbic acid and dehydroascorbic acid by titration with 2,6-dichloro-
phenolindophenol. Journal of AOAC International. 1996;79:1236
[40] Xia W, Yuxia D, Changxia S, Jinghe Y, Yuebo W, Shuna S. Fluorimetric determination of
ascorbic acid with o-phenylenediamine. Talanta. 2003;59:95-99
[41] Rahman Khan MM, Rahman MM, Islam MS, Begum SA. A simple UV-spectrophotometric
method for the determination of vitamin C content in various fruits and vegetables at
Sylhet area in Bangladesh. Journal of Biological Sciences. 2006;6:388-392
[42] Nyyssönen K, Salonen JT, Parviaine MT. Ascorbic acid. In: De Leenheer AP, Lambert
WE, Van Bocxlaer JF, editors. Modern Chromatographic Analysis of Vitamins. 3rd ed.
Marcel Dekker:  New York; 2000
[43] Casella L, Gulloi M, Marchesini M, Petrarulo M. Rapid enzymatic method for vitamin
C assay in fruits and vegetables using peroxidase. Journal of Food Science. 2006;54:374
[44] Ensa AA, Rezaei B, Movahedinia H. Kinetic–spectrophotometric determination of
ascorbic acid by inhibition of the hydrochloric acid–bromate reaction. Spectrochimica
Acta Part A: Molecular and Biomolecular Spectroscopy. 2002;58:2589-2594
[45] Safavi A, Fotouhi L. Kinetic spectrophotometric determination of ascorbic acid by reduc-
tion of toluidine blue. Talanta. 1994;41:1225-1228
Vitamin C18
[46] Nováková L, Solich P, Solichová D. HPLC methods for simultaneous determination of
ascorbic and dehydroascorbic acids. Trends in Analytical Chemistry. 2008;27:942
[47] Racz E, Parlagh-Huszar K, Kecskes T. HPLC method for determination of ascorbic acid
in fruits and vegetables. Periodica Polytechnica Chemical Engineering. 1991;351-2:23-30
[48] Snezana SM, Danijela AK, Danijela CN, Milan NM. Rapid and reliable HPLC method
for the determination of vitamin C in pharmaceutical samples. Tropical Journal of
Pharmaceutical Research. 2011;10(1):105-111
[49] Franco VV, María EP, María SC, Daniel RG, del H. Bernardi CM. Optimization and valida-
tion of a UV–HPLC method for vitamin C determination in strawberries (Fragaria anan-
assa Duch.), using experimental designs. Food Analytical Methods. 2012;5:1097-1104
[50] Line R, Hoer LJ. A simple method for plasma total vitamin C analysis suitable for rou-
tine clinical laboratory use. Nutrition Journal. 2016;15:40
[51] Güçlü K, Sözgen K, Tütem E, Özyürek M, Apak R. Spectrophotometric determination of
ascorbic acid using copper(II)-neocuproine reagent in beverages and pharmaceuticals.
Talanta. 2005;65(5):1226-1232
[52] Danet AF, David V, Oancea M. Dispozitiv de analiza in ux cu injectarehidrodinamica.
Determinareavitaminei C, Revista de Chimie. 1994;45(11):1000-1006
[53] Danet BM, Aboul-Enein HY. Flow injection system with chemiluminometric detection
for enzymatic determination of ascorbic acid. Luminescence. 2000;155:305-309
[54] Kobra Z, Somayye M. Sensitive spectrophotometric determination of ascorbic acid in
drugs and foods using surface plasmon resonance band of silver nanoparticles. Cogent
Chemistry. 2015;1:1109172
[55] Kapur A, Hasković A, Čopra-Janićijević A, Klepo L, Topčagić A, Tahirović I, Soć E.
Spectrophotometric analysis of total ascorbic acid contetnt in various fruits and vegeta-
bles. Bulletin of the Chemists and Technologists of Bosnia and Herzegovina. 2012;38:39-42
[56] Mohammed IHM, Hazim YA. Determination of Vitamin C (ascorbic acid) Contents in
various fruit and vegetable by UV-spectrophotometry and titration methods. Journal of
Chemical and Pharmaceutical Sciences. 2016;9:2972
[57] Ahmed Z, Mohamed H. Spectrophotometric determination of ascorbic acid in aque-
ous solutions and in pharmaceuticals formulations. Journal of Al-Nahrain University.
2013;16:65-71
[58] Cooper JA, Woodhouse KE, Chippindale AM, Compton RG. Photoelectrochemical
determination of ascorbic acid using methylene blue immobilized in α-zirconium phos-
phate. Electroanalysis. 1999;11:1259-1265
[59] Morais H, Rodrigues P, Ramos C, Forgcs E, Cserhti T, Oliveira J. Eect of ascorbic acid
on the stability of β-carotene and capsanthin in paprika (Capsicum annuum) powder.
Nahrung/Food. 2002;46:308-310
Vitamin C: Sources, Functions, Sensing and Analysis
http://dx.doi.org/10.5772/intechopen.70162
19
[60] Julio CBF, Lauro TK, Graciliano DON. Potentiometric sensor for -ascorbic acid based
on EVA membrane doped with copper (II). Electroanalysis. 1999;11:475-480
[61] Song Z, Qun X, Wen Z, Litong J, Ji YJ. In vivo monitoring of the monoamine neurotrans-
-
chemical detection. Analytica Chimica Acta. 2001;427:45-53
[62] 
dopamine. Journal of Electroanalytical. Chemistry. 1996;407:183-187
[63] Adriana DD, Jairo JP, Ivano GRG. A batch injection analysis system for ascorbic acid
determination using amperometric detection on a sessile mercury drop electrode.
Electroanalysis. 1999;11:1124-1129
[64] Andrei DF, Mihaela B, Hassan YAE. Flow injection system with chemiluminometric
15:305-309
[65] 
acid and its application to the electrocatalytic determination of ascorbic acid. Journal of.
Electroanalytical Chemistry. 2001;515:45-51
[66] 
14:1597-1600
[67]      

Films by simple electroless dipping method. Electroanalysis. 2002;14:206-219
[68] Suw YL, Jung IC, Young SJ, Woon WJ, Hye JL, Seong HL. Electrochemical detection of
ascorbic acid (vitamin C) using a glassy carbon electrode. Nahrung/Food. 2004;3:201-204
[69] Sudha JD, Neethu KS, Renjith S, Hans-Juergen PA, Pich A. Water dispersible electrically
conductive poly (3,4-ethylenedioxythiophene) nanospindles by liquid crystalline tem-
2:6991
[70] Reena VL, Sudha JD, Rohini KN, Neethu KS. Design of a nanostructured electro-
      
for the nanomolar detection of ascorbic acid. Journal of Applied Polymer Science.
2014;131:40936-4094
Vitamin C20
... Salah satu komponen yang sering digunakan dalam sediaan multivitamin adalah vitamin C. Vitamin C berfungsi membantu sintesis dan metabolisme tirosin, asam folat dan triptofan, hidroksilasi glisin, prolin, lisin karnitin dan katekolamin. Kekurangan vitamin C sering dikaitkan dengan penyakit anemia, infeksi, gusi berdarah, skorbut, penyembuhan luka yang buruk, perdarahan kapiler, degenerasi otot, plak aterosklerotik, dan gangguan sistem saraf [5], [6]. Vitamin C dapat digunakan sebagai terapi pendukung dalam penanganan COVID-19 karena kemampuannya sebagai antioksidan, antiinflamasi, antitrombotik dan imunodulator. ...
Article
Vitamin C memiliki gugus kromofor dan dapat dianalisis menggunakan spektrofotometri UV, namun apabila matriks yang akan dianalisis berupa multivitamin yang kompleks diperlukan metode pemisahan yang selektif untuk mengurangi interferensi dari matriks. Salah satu metode pemisahan yang selektif dalam pemisahan adalah Molecular Imprinted Polymer (MIP) yang belum banyak digunakan dalam sampel multivitamin. Penelitian ini bertujuan untuk memperoleh MIP yang selektif untuk pemisahan vitamin C dalam sediaan multivitamin. Metode penelitian meliputi pengamatan interaksi vitamin C dengan monomer fungsional menggunakan spektrofotomeri UV. MIP disintesis dengan menggunakan metode ruah selama 24 jam pada suhu 60 °C. MIP dikarakterisasi menggunakan menggunakan spektrofotometri inframerah dan scanning electron microscopy. Selektivitas MIP ditentukan dengan pengujian faktor imprinting dan perbandingan perolehan kembalinya terhadap metode ekstraksi cair-cair (ECC) dan SPE C18 untuk pemisahan vitamin C dalam sampel multivitamin di pasaran menggunakan metode yang telah tervalidasi. Pergeseran hipsokromik menunjukkan adanya interaksi antara vitamin C dengan monomer fungsional di mana ikatan hidrogen berperan dominan dalam sintesis MIP. Faktor imprinting yang lebih dari 1 dan nilai perolehan kembali yang mendekati 100% menunjukkan selektivitas MIP terhadap vitamin C. MIP-1 memiliki selektivitas paling tinggi dibandingkan dengan metode ECC dan SPE C18 untuk pemisahan vitamin C dalam sampel multivitamin dengan persen perolehan kembali berturut-turut sebesar 98,17±2,31%, 69,42±3,01%, dan 93,26±4,24%. MIP-1 yang dihasilkan selektif untuk pemisahan vitamin C dalam sediaan multivitamin.
... Additionally, it protects the body against free radical oxidation and as an antioxidant, destroys cancer cells. It also participates in numerous physiological activities, such as collagen formation and tissue or fractured bone/tooth/cartilage repair [31], and owing to its antioxidation functions, it can be used to treat CVDs. It can also decrease monocyte adhesion onto endothelium, promote vasodilation, and endothelium-dependent nitric oxide generation, while attenuating vascular smooth muscle cell apoptosis, thereby avoiding unstable plaque formation in atherosclerosis [32]. ...
Preprint
Full-text available
Background Pulpitis, a pulp disease caused by several factors, including caries and trauma, has a high clinical incidence. In this study, our aim was to identify possible metabolic biomarkers in individuals with pulpitis and analyze the associated metabolic pathways to the end of providing a theoretical basis for pulpitis diagnosis and prevention. Methods Pulp samples from 12 individuals (six patients with pulpitis and six individuals with normal teeth) were analyzed via serum metabolomics based on ultra-high-performance liquid chromatography (UPLC)/Orbitrap mass spectrometry. Thereafter, to identify important biomarkers, we performed multivariate analysis and also established an orthogonal partial least squares discrimination analysis model. Further, we performed correlation analysis as well as biomarker pathway enrichment analysis to determine the associations between the differentially expressed biomarkers as well as their association with different biological pathways. Results 22 biomarkers (13 upregulated and nine downregulated) we found to be significantly associated with 18 metabolic pathways in pulpitis. Specifically, the major biomarkers included ascorbic acid, inosine, allopurinol riboside, and L-asparagine, and among these, ascorbic acid and inosine were most significantly downregulated and showed the strongest correlation with pulpitis. Additionally, aminoacyl-tRNA biosynthesis and retrograde endocannabinoid signaling showed positive correlation with pulpitis. Conclusions These identified pulpitis-associated biomarkers and metabolic pathways may serve as a theoretical basis for further clarifying the pathogenesis of pulpitis and can be applied in the development of preventive drugs.
... AA plays an important physiological role in cellular redox metabolism by participating in free radical scavenging and immune system boosting. Antioxidant activity of AA helps to prevent certain diseases such as cancer, hypertension, neurodegenerative diseases, age-related muscular degeneration, cataracts, etc. [1,2]. AA is involved in the physiology of the nervous system, including the support and the structure of the neurons, and the processes of differentiation, maturation, and neuronal survival [3]. ...
Article
Full-text available
Nowadays, micro-sized sensors have become a hot topic in electroanalysis. Because of their excellent analytical features, microelectrodes are well-accepted tools for clinical, pharmaceutical, food safety, and environmental applications. In this brief review, we highlight the state-of-art electrochemi-cal non-enzymatic microsensors for quantitative detection of ascorbic acid (also known as vitamin C). Ascorbic acid is a naturally occurring water-soluble organic compound with antioxidant properties and its quantitative determination in biological fluids, foods, cosmetics, etc., using electrochemical microsensors is of wide interest. Various electrochemical techniques have been applied to detect ascorbic acid with extremely high sensitivity, selectivity, reproducibility, and reliability, and apply to in vivo measurements. This review paper aims to give readers a clear view of advances in areas of electrode modification, successful strategies for signal amplification, and miniaturization techniques used in the electroanalytical devices for ascorbic acid. In conclusion, current challenges related to the microelectrodes design, and future perspectives are outlined.
... However, vitamin C is a powerful antioxidant that assists the body in contesting viral infection, bacterial infection and toxicity. [35] Deficiency of Vitamin C causes Bruising, Bleeding, Skin and hair loss. The symptoms are all related to diminished levels of Collagen in bones, blood vessels and connective tissues. ...
Article
Full-text available
Velvet tamarind (Dialium guineense) is a wild fruit commonly grown and consumed in northern part of Nigeria. However, this study aimed at investigating the proximate, mineral, vitamin C and antioxidant potentials of velvet tamarind (seed, pulp and shell) using standard analytical procedures. The result of the proximate analysis showed that the pulp recorded highest percent crude protein (18.34%) and crude fat (4.92%) which also contributed to its highest calculated metabolizable energy (1536.43 KJ/100g) in the study while percentage moisture (7.67%) and carbohydrate (75.60%) were found to be highest in seed, and the shell were found to be highest in terms of crude fibre (10.47%) and ash contents (6.82%) respectively. The result of the mineral analysis revealed highest concentrations of Zn (6.30 ± 0.01 mg/100g), Ca (370.01 ± 0.08 mg/100g), and Mg (200.01 ± 0.04 mg/100g) in the pulp while highest concentrations of K (486.24 ± 2.10 mg/100g), Na (73.68 ± 0.03 mg/100g), and Fe (4.70 ± 0.01 mg/100g) were found in the seed. The vitamin C content was found to be highest in the seed (32 ± 0.05 mg/100) which also resulted to its higher antioxidant activity compared to the pulp and the shell. However, based on the results obtained, it could be inferred that velvet tamarind (shell, pulp and seed) are good sources of nutrients especially the pulp and the seed and could serve as natural antioxidant if incorporated in human diet.
... DHA is one of the most common precursor forms of edible food in seafood, such as algae, selfish, and fish, that can regenerate ascorbic acid [55,56]. Ascorbic acid is involved in many biological functions, such as feed conversion, growth performance, reproduction of aquatic animals, and maintenance of innate immune responses [57]. ...
Article
Full-text available
Thioredoxins are small ubiquitous redox proteins that are involved in many biological processes. Proteins with thiol-disulfide bonds are essential regulators of cellular redox homeostasis and diagnostic markers for redox-dependent diseases. Here, we identified and characterized the thioredoxin domain-containing protein 12 (EaTXNDC12) gene in red spotted grouper (Epinephelus akaara), evaluated transcriptional responses, and investigated the activity of the recombinant protein using functional assays. EaTXNDC12 is a 19.22-kDa endoplasmic reticulum (ER)-resident protein with a 522-bp open reading frame and 173 amino acids, including a signal peptide. We identified a conserved active motif (⁶⁶WCGAC⁷⁰) and ER retention motif (¹⁷⁰GDEL¹⁷³) in the EaTXNDC12 amino acid sequence. Relative EaTXNDC12 mRNA expression was analyzed using 12 different tissues, with the highest expression seen in brain tissue, while skin tissue showed the lowest expression level. Furthermore, mRNA expression in response to immune challenges was analyzed in the head kidney, blood, and gill tissues. EaTXNDC12 was significantly modulated in response to bacterial endotoxin lipopolysaccharide (LPS), nervous necrosis virus (NNV), and polyinosinic:polycytidylic acid (poly(I:C)) challenges in all of the tested tissues. Recombinant EaTXNDC12 (rEaTXNDC12) displayed antioxidant ability in an insulin reductase assay, and a capacity for free radical inhibition in a 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay. In addition, a DNA nicking assay revealed that purified rEaTXNDC12 exhibited concentration-dependent DNA protection activity, while results from 2-hydroxyethyl disulfide and L-dehydroascorbic assays indicated that rEaTXNDC12a possesses reducing ability. Furthermore, fathead minnow (FHM) cells transfected with EaTXNDC12-pcDNA demonstrated significantly upregulated cell survival against H2O2-induced apoptosis. Collectively, the results of this study strengthen our knowledge of EaTXNDC12 with respect to cellular redox hemostasis and immune regulation in Epinephelus akaara.
... Apart from being rich in provitamin A, carrots also rich in vitamin C (Char, 2018). Vitamin C is a water-soluble vitamin founded in various fruits and vegetables (Devaki & Raveendran, 2017). Vitamin C in carrots is available in the form of ascorbic acid. ...
Article
Full-text available
Carrots (Daucus carota L.) are vegetables proven to have nutraceutical effects and beneficial for health due to its natural bioactive substances. One of the potential of carrots to maintain optimum health status is by regulating immune response. This literature review summarized the proposed immunomodulatory mechanisms of the antioxidant properties of carrot’s β-carotene and other bioactive compounds such as phenolic acid, flavonoid, polyacetylene and ascorbic acid via the anti-inflammatory, antioxidant and overall (innate and adaptive) immune response modulation. Overall, carrot’s bioactive compounds regulated pro-inflammatory and anti-inflammatory cytokines, reduced oxidative stress by decreasing the reactive oxygen species accumulation and improving antioxidant capacity and the expression of genes in order to prevent more damaging oxidative destruction. Carrots also modulated the immune components by regulating leukocytes, antigens, immunoglobulins, and histamine levels. Thus, the immunomodulatory activity makes carrots as a functional food source that has the potential to prevent and treat various diseases.
... Guava fruits are easy to process into a variety of nutrient-rich products. Vitamin C is indispensable for growth, development, and tissue repair in the human body (12). Guava is a natural source of vitamin C content that is ∼2-5 times higher than that of citrus (13). ...
Article
Full-text available
Amid environmental crises, a galloping population, and changing food habits, increasing fruit production with nutritional quality is a global challenge. To address this, there is a necessity to exploit the germplasm accessions in order to develop high-yielding varieties/hybrids with good adaptability and high quality fruit under changing environmental and biological conditions. In the study, a total of 33 morpho-biochemical traits enabled an assessment of the genetic variability, diversity, and structure in a collection of 28 diverse germplasm lines of guava. Results showed that highly significant genetic variability existed in the studied traits in the guava germplasm. The coe�cient of variation values for the qualitative and quantitative traits varied from 23.5–72.36 to 1.39–58.62%, respectively. Germplasm Thai, Lucknow�49, Punjab Pink, Psidium friedrichsthalianum, and Shweta had the highest fruit weight (359.32 g), ascorbic acid content (197.27 mg/100 g fruit), total phenolic content (186.93 mg GAE/100 g), titratable acidity (0.69 percent), and antioxidant capacity (44.49 µmolTrolox/g), respectively. Fruit weight was positively correlated with ascorbic acid content; however, titratable acidity was negatively correlated with fruit weight. The principal component analysis (PCA) was 84.2% and 93.3% for qualitative and quantitative traits, respectively. Furthermore, K-mean clustering was executed; the population was grouped into three clusters for both traits. Additionally, the dendrogram using agglomerative hierarchical clustering (AHC), where all the germplasm were grouped into four clusters, revealed that among the clusters, clusters III and IV were highly divergent. The high variability, diversity, and structure could be utilized for the breeding programme of guava and also explored for molecular analysis using next-generation technology to enhance the guava yield and nutrition properties and also develop the climate resilient technology to fulfill the existing demand gap and nutrition availability, which could not only mitigate the nutrition requirement but also enhance the easy availability of fruits year-round.
... Vitamin C also known as ascorbic acid is an important water soluble antioxidant which found mainly in vegetables and fruits [1]. Consumption of this prevents most of the diseases like scurvy, cancer, cardiovascular diseases, common cold, age-related muscular degeneration and cataract by stimulating the immune system [2]. Ascorbic acid has to be supplemented through the nature like fruits and vegetables and other resources as human body cannot synthesize it for their own requirement due to lack of an enzyme Gulonolactone Oxidase. ...
Article
Full-text available
This experimental work aimed to evaluate and compare the ascorbic acid content of selected seasonal vegetables, dried at different temperatures (30,40,50 and 60 0 C) using various drying methods. Study of treatment effectiveness for retention of Vitamin C with different heat environment is highly needed for market acceptability of dried product. The seasonal vegetables like Potato (Solanum tuberosum L.), Tomato (Lycopersicon esculentum L.), Onion (Allium cepa L), Bittergourd (Momordica charantia L.) and Brinjal (Solanum melongena L.) were selected for experimental study and performed a comparative investigation for retention of ascorbic acid through dye titration method for fresh and dried samples. Retention of vitamin C in mg/100g was evaluated for selected vegetable samples using open sun, waste heat, solar and hybrid solar drying methods. The range of % retention effectiveness was found better for Bittergourd (25.72-75.3%) and Potato (8.36-68.01%) as compared to Tomato (3.66-6.06%) and Onion (4.62-7.07%) using different treatments of drying environment. Analysis of varience was also performed for the retention of vitamin C in fresh and dried forms of different selected vegetables with various drying methods.
Article
Tissue engineering approach aims to overcome the transplant drawbacks and facilitate tissue repair and regeneration. Here, a new conductive, highly porous, and flexible polycaprolactone/gelatin/polypyrrole/graphene 3D scaffolds for nerve tissue repair is presented. A simple and efficient porogen leaching fabrication method is applied to create a 3D network with a pore radius of 3.8 ± 0.7 to 4.2 ± 0.8 μm with an exceptional uniform circular porous structure. The conductivity of the polymeric scaffold without graphene, in wet conditions, was found to be 0.78 ± 0.1 S.m−1 and it increased to 3.3 ± 0.2 S.m−1 for the optimized sample containing 3wt% graphene (G3). Tensile strength was measured at 163 KPa for the base sample (without graphene) and improved to 526 KPa for G3 sample. Following 42 days of incubation in PBS, 32.5% degradation for the base sample (without graphene) was observed. The cell study demonstrated a non‐cytotoxic nature of all scaffolds tested and the cells had mostly stretched and covered the surface. Overall, the sum of results presented in this study demonstrate a simple fabrication platform with extraordinary aspects that can be utilized to mimic the native conductive tissue properties, and also because of its flexibility it can easily be rolled into a nerve conduit to fill gaps in nerve tissue regeneration.
Article
Full-text available
Background In-hospital hypovitaminosis C is highly prevalent but almost completely unrecognized. Medical awareness of this potentially important disorder is hindered by the inability of most hospital laboratories to determine plasma vitamin C concentrations. The availability of a simple, reliable method for analyzing plasma vitamin C could increase opportunities for routine plasma vitamin C analysis in clinical medicine. Methods Plasma vitamin C can be analyzed by high performance liquid chromatography (HPLC) with electrochemical (EC) or ultraviolet (UV) light detection. We modified existing UV-HPLC methods for plasma total vitamin C analysis (the sum of ascorbic and dehydroascorbic acid) to develop a simple, constant-low-pH sample reduction procedure followed by isocratic reverse-phase HPLC separation using a purely aqueous low-pH non-buffered mobile phase. Although EC-HPLC is widely recommended over UV-HPLC for plasma total vitamin C analysis, the two methods have never been directly compared. We formally compared the simplified UV-HPLC method with EC-HPLC in 80 consecutive clinical samples. Results The simplified UV-HPLC method was less expensive, easier to set up, required fewer reagents and no pH adjustments, and demonstrated greater sample stability than many existing methods for plasma vitamin C analysis. When compared with the gold-standard EC-HPLC method in 80 consecutive clinical samples exhibiting a wide range of plasma vitamin C concentrations, it performed equivalently. Conclusion The easy set up, simplicity and sensitivity of the plasma vitamin C analysis method described here could make it practical in a normally equipped hospital laboratory. Unlike any prior UV-HPLC method for plasma total vitamin C analysis, it was rigorously compared with the gold-standard EC-HPLC method and performed equivalently. Adoption of this method could increase the availability of plasma vitamin C analysis in clinical medicine.
Article
Full-text available
Development of improved methods for the synthesis of copper nanoparticles is of high priority for the advancement of material science and technology. Herein, starch-protected zero-valent copper (Cu) nanoparticles have been successfully synthesized by a novel facile route. The method is based on the chemical reduction in aqueous copper salt using ascorbic acid as reducing agent at low temperature (80 °C). X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy measurements were taken to investigate the size, structure and composition of synthesized Cu nanocrystals, respectively. Average crystallite size of Cu nanocrystals calculated from the major diffraction peaks using the Scherrer formula is about 28.73 nm. It is expected that the outcomes of the study take us a step closer toward designing rational strategies for the synthesis of nascent Cu nanoparticles without inert gas protection.
Article
Full-text available
A simple and sensitive procedure was proposed for spectrophotometric determination of ascorbic acid. It was found that the reduction of Ag+ to silver nanoparticles (Ag-NPs) by ascorbic acid in the presence of polyvinylpyrrolidone (PVP) as a stabilizing agent produce very intense surface plasmon resonance peak of Ag-NPs. The plasmon absorbance of the Ag-NPs at λ = 440 nm allows the quantitative spectrophotometric detection of the ascorbic acid. The calibration curve was linear with concentration of ascorbic acid in the range of 0.5–60 μM. The detection limit was obtained as 0.08 μM. The influence of potential interfering substances on the determination of ascorbic acid was studied. The proposed method was successfully applied for the determination of ascorbic acid in some powdered drink mixtures, commercial orange juice, natural orange juice, vitamin C injection, effervescent tablet, and multivitamin tablet.
Article
Total vitamin C (ascorbic acid + dehydroascorbic acid) has been investigated using two methods, the first UV-spectrophotometric method and the second titration method. In the two methods, a blended sample of various fruit and vegetable in Hill region is homogenized with 85% Sulphuric acid-10% acetic acid solution, the effect of bromine water has been added to oxidize ascorbic acid to dehydroascorbic acid with using acetic acid. In this step the excess of percentage of bromine has been removed when added 3-4 drops of 10% thiourea. After coupling with 2,4-dinitrophenyl hydrazine at 37°C temperature two hours the solution has been cooled by using ice bath after that solution must treated with dilute sulphuric acid to produce a red color complex all prepared solution of fruits and vegetables has been measured at maximum absorbance 280nm. The results revealed that ascorbic acid content was very high in Orange and Kiwi while it was very low in Red pepper, Cabbage and Tomato. The comparison between the two methods the spectroscopy method has been preferred to obtain the value of ascorbic acid than the titrimetric method. The scientists prove that the vitamin c have been important vitamin for the human health .Ascorbic acid is reversibly oxidized to form L-dehydroascorbic acid (DHA) which also exhibits biological activity. Dehydroascorbic acid has been converted into acetic acid in the human body. For determine the activity of vitamin c its important determined both acetic acid and Dehydro ascorbic acid in fruits and vegetables. Vitamin C is the real water-soluble antioxidant within the body. It lowers blood pressure and levels cholesterol .Recently many articles bas been shown that the effect of vitamin c reduced the risk of developing cancers of breast, colon, rectum, lung, mouth. Vitamin C is generally non-Toxic. Vitamin c very important for everybody such as formation bone and tissue repair. Vitamin C is generally non-toxic. To maintain a good and sound health and the prevention of colds a healthy body, the human must remain saturated with vitamin C. Keeping in view its importance; the estimation of vitamin C containing this vitamin assumes significance. And a wide range of nutrients present contains vitamin C. It is known widely by ordinary people today that the best sources of vitamin C are citrus fruits and juices. To make better use of fruits and vegetables as food, mortal, and a clear understanding of the nutritional value, as well as estimating the content of vitamin C is necessary. The aim of this project has been estimate the value of ascorbic acid .Ten common Iraqi fruits using methods iodometric titration and UV-spectrophotometry under three temperature regimes representing the ranges the fruits may be exposed to during processing and storage. The redox reaction is preferable to an acid base titration because a number of other species in juice can act as acids. This work helped to demonstrate the effects of processing and storage on the ascorbic acid contents of these fruits. 2. MATERIALS AND METHODS Materials: 10% Acetic acid, 10% Thio Urea, 2,4-Dinitrophenyl Hydrazine, 85% Sulphuric acid, 5-Bromine water, 10% potassium iodide, 1 M potassium iodate (KIO3), Sodium thiosulphate, 3% Starch Solution Instrument: Apple-UV-visible spectrophotometer with 1 cm cell was used. Sample preparation and evaluation of ascorbic acid by method spectrophotometer: In this work different kind of fruits and vegetables has been choice for investigated to determine the amount of ascorbic acid in this samples. All samples has been blended then filtered using Buchner, 10 gm of each sample was transferred into a 100ml volumetric flask homogenized by using 50ml acetic acid solution with shaken, 4-5 drops of bromine water has been added until the solution became colored, Then a few drops of thiourea solution were added to it to remove the excess bromine and thus the clear solution was obtained. Then 2, 4-Dinitrophenyl hydrazine solution was added thoroughly with all standards and also with the oxidized ascorbic acid. Then complete the solution up to the mark with acetic acid. The absorbance for all samples has been measured using Apple-UV-visible spectrophotometer to determine the concentration of ascorbic acid in the fruits and vegetables under testing. Sample preparation and evaluation of ascorbic acid by method redox Titration: 10 ml of each of the fruit and vegetable samples was pipetted into a pre-washed conical flask and 5 ml of 10% potassium iodide (KI) with 1 ml of 0.3 M sulphuric acid (H2SO4) were added into the flask. 10 ml of 0.01 M potassium iodate (KI03) was also added into the flask. The excess iodine generated was titrated against 0.01 M sodium thiosulphate (Na2S2O3) solution blank titration was carried out with 10 ml of distilled water.
Article
A polyviologen-modified glassy carbon electrode (PV-GCE) was applied to directly determine vitamin C (i.e., ascorbic acid) in deeply colored, viscous, and turbid fruit juice samples. Compared to the results obtained at a bare GCE, the oxidation of vitamin C showed a large increase in current response at the PV-GCE in pH 4 buffer solutions. Preconcentration is the major factor for the signal enhancement. Square-wave voltammetry (SWV) was used for vitamin C detection at the PV-GCE. Under the optimized conditions, the SWV current signals showed a very wide linear range (up to 900 muM) with slope band regression coefficient of 0.051 muM muA(-1) and 0.998, respectively. The detection limit (S/N = 3) was 0.38 muM after 20 s of accumulation at open circuit. Since the content of vitamin C and pH value of most fruit juices are lower than 900 muM and close to pH 4, the determination can be done without dilution and other pretreatment of the samples. The results demonstrated a good precision and are in agreement with those obtained with other method.
Article
Ascorbic acid is frequently determined by titration with 2,6-dichlorophenolindophenol. The determination is rapid, but the method is neither specific for ascorbic acid nor very sensitive. The coloring matter in the assay solution interferes with the visual endpoint, and iron(II), copper(I), sulfite, and sulfhydryl substances such as cysteine and glutathione interfere with the color reaction. Sample cleanup by solid-phase extraction with C18 bonded silica was developed to remove the coloring matter. Extraction sorbent impregnated with 2,2′-bipyridyl, 2,9-dimethyl-1,10-phenanthroline (neocuproine) and N-ethylmaleimide removes Fe(II), Cu(I), and sulfhydryl compounds, respectively. The procedure was applied to highly colored multivitamin pharmaceuticals, soft drinks, and fruit and vegetable juices. In contrast to the results from the original method, which is not applicable to such samples, the results obtained by the method incorporating cleanup were accurate and selective for ascorbic acid. The sample cleanup also permitted determination of dehydroascorbic acid by reducing it to ascorbic acid with cysteine and titrating the ascorbic acid formed with indophenol. As little as 3 ng ascorbic acid was determined by the method incorporating cleanup.