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XYLITOL: A SUGAR SUBSTITUTE FOR PATIENTS OF DIABETES MELLITUS

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Abstract

India figures conspicuously around the world for rapid growing of diabetes at a high rate and every fifth diabetic in the world is found to be Indian. India is also termed as " Diabetic capital of world " with high prevalence of disease among South Indian population. Obesity, food insecurity, illiteracy, poor sanitation, poor glycemic control and dominance of communicable diseases are the main factors responsible for developing this disease at a fast rate among Indian people. The treatment approaches currently used against diabetes are use of oral drugs, amylin agonists, glucagon antagonists, protein tyrosine phosphatase inhibitors, salicylate derivatives and G protein coupled receptors. The currently used therapeutic approaches against diabetes are costly and resulting in various side effects like allergic reactions, swollen ankles, weight gain, abdominal pain and digestive disturbances. The use of natural alcoholic sugars like sorbitol, mannitol, xylitol, erythritol, maltitol and lactitol is another alternative treatment against diabetes for controlling sugar levels. Among various alcoholic sugars, xylitol is found to be most effective due to its unique properties, resulting in its wide use in many industrial applications. In addition, GRAS status has been given to xylitol by FDA, USA in 1986 and is approved to be safe for human consumption. Currently, most of the xylitol demand has been met by its chemical synthesis, which is costly and resulting in low product yield. The alternative approach for synthesis of xylitol is biotechnological methods using whole cells and enzymatic methods by utilizing various low cost agricultural wastes as raw materials to decrease its production cost and increasing product yield. The Government of India should
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Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
XYLITOL: A SUGAR SUBSTITUTE FOR PATIENTS OF DIABETES
MELLITUS
Yogita Lugani1, Simmi Oberoi2 and *Balwinder Singh Sooch1
1Enzyme Biotechnology Laboratory, Department of Biotechnology, Punjabi University,
Patiala-147002, Punjab, India.
2Department of Community Medicine, Government Medical College, Patiala-147001,
Punjab, India.
ABSTRACT
India figures conspicuously around the world for rapid growing of
diabetes at a high rate and every fifth diabetic in the world is found to
be Indian. India is also termed as „Diabetic capital of world‟ with high
prevalence of disease among South Indian population. Obesity, food
insecurity, illiteracy, poor sanitation, poor glycemic control and
dominance of communicable diseases are the main factors responsible
for developing this disease at a fast rate among Indian people. The
treatment approaches currently used against diabetes are use of oral
drugs, amylin agonists, glucagon antagonists, protein tyrosine
phosphatase inhibitors, salicylate derivatives and G protein coupled
receptors. The currently used therapeutic approaches against diabetes
are costly and resulting in various side effects like allergic reactions, swollen ankles, weight
gain, abdominal pain and digestive disturbances. The use of natural alcoholic sugars like
sorbitol, mannitol, xylitol, erythritol, maltitol and lactitol is another alternative treatment
against diabetes for controlling sugar levels. Among various alcoholic sugars, xylitol is found
to be most effective due to its unique properties, resulting in its wide use in many industrial
applications. In addition, GRAS status has been given to xylitol by FDA, USA in 1986 and is
approved to be safe for human consumption. Currently, most of the xylitol demand has been
met by its chemical synthesis, which is costly and resulting in low product yield. The
alternative approach for synthesis of xylitol is biotechnological methods using whole cells
and enzymatic methods by utilizing various low cost agricultural wastes as raw materials to
decrease its production cost and increasing product yield. The Government of India should
WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES
SJIF Impact Factor 6.647
Volume 6, Issue 4, 741-749 Review Article ISSN 2278 4357
Article Received on
01 Feb. 2017,
Revised on 21 Feb. 2017,
Accepted on 13 Mar. 2017
DOI: 10.20959/wjpps20174-8946
*Corresponding Author
Balwinder Singh Sooch
Enzyme Biotechnology
Laboratory, Department of
Biotechnology, Punjabi
University, Patiala-
147002, Punjab, India.
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742
Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
also need to focus on planning some projects on utilization of these agricultural wastes,
which are produced in huge amounts annually in India, for xylitol production to fulfill the
need of xylitol for Indian market.
KEYWORDS: Xylitol, Xylose, Diabetes, Xylitol, Agricultural waste, Sweetener, Alcoholic
sugar.
INTRODUCTION
Diabetes is a rapidly growing non communicable disease in India with prevalence of 69.2
million and it is rising day by day at a high rate.[1] This disease is found to be more prevalent
among the population of urban areas compared to rural one. Various studies indicate the high
prevalence of diabetes among people of South Indians than North Indians.[2] Obesity, food
insecurity, illiteracy, poor sanitation, poor glycemic control and dominance of communicable
diseases are the main factors responsible for this disease.[3-4] Currently, various therapeutic
approaches are available to control diabetes, however, these treatments are not cost effective
and associated with many side effects. The use of natural alcoholic sugars like sorbitol,
mannitol, xylitol, erythritol, maltitol and lactitol is another alternative strategy against
diabetes for controlling sugar levels. Amongst various alcoholic sugars, xylitol is found to be
most effective due to its unique properties like sweetening power similar to sucrose, its
metabolism independent to insulin, absence of maillard reaction, negative heat of dissolution,
anticariogenicity and antiketogenicity. The current paper summarizes the magnitude of
diabetes in India, need to control diabetes, treatments available for this disease, use of xylitol
as sugar substitute for diabetic patients, processes for xylitol production, global status and
safety issues of xylitol.
MAGNITUDE OF DIABETES: INDIAN SCENARIO
Diabetes is growing rapidly at an alarming rate in India and that is why India is being termed
as „diabetes capital of world‟.[5] Currently, the prevalence of this major non communicable
disease (NCD) in India is 69.2 million, which is expected to be rise at a rate of 78.5% (123.5
million) by the year 2040. From the world record with diabetic patients, every fifth diabetic
in the world is found to be an Indian.[1] The Atlas of Diabetes (2006) published by
International Diabetes Federation revealed the urgent need to follow the preventive steps
against this rapidly rising disease.[5] The incidence of diabetes varies with the geographical
distribution with one quarter in rural populations that of urban populations.2 The first national
study on prevalence of diabetes was done between 1972 and 1975 by Indian Council of
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Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
Medical Research (ICMR) and this disease was found to be highly prevalent in urban
population compared to rural population.[6] Previous studies conducted by Indian Council of
Medical Research (ICMR) proved the lower prevalence of this disease in population of North
India like Chandigarh, 0.12 million and Jharkhand, 0.96 million compared to other states like
Maharashtra, 9.2 million and Tamil Nadu, 4.8 million.[2] Similar trend of diabetes were
recorded in metropolitan cities located in different directions of India like Kolkata, 11.7%;
Kashmir Valley, 6.1%; New Delhi, 11.6%; Mumbai, 9.3%; South India: Chennai, 13.5%;
Hyderabad, 16.6% and Bangalore, 12.4% by National Urban Diabetes Survey.[7]
NEED TO CONTROL DIABETES
The major concern of rising diabetes was also noticed by the Government of India due to
rapid increase of this deadly disease, which has reached at epidemic range in some parts of
the country. This epidemic disease results in loss of national productivity and exchequer at
social level. There is an immediate need to generate awareness among people for early
detection, cost effective management and rehabilitation of diabetic patients.[8] The major
factors responsible for this disease are obesity, food insecurity, illiteracy, poor sanitation,
poor glycemic control and dominance of communicable diseases. It is clear from the world
record that diabetes is very prevalent among the people of India and thus it has become
important to control the spread of this disease at a large scale. Many previous studies on
diabetes also suggested the need for developing government policies, interventions and public
awareness programmed in India to overcome the spread of this disease in the future
generation.[9-10]
TREATMENTS AVAILABLE TO CONTROL DIABETES
Several oral drugs like biguanides, sulfonylureas, glinides, thiazolidinediones, amylin
agonists, glucagon antagonists, protein tyrosine phosphatase inhibitors, salicylate derivatives
and G protein coupled receptors are used to treat diabetes.[11] However, these treatments are
costly and associated with many side effects like allergic reactions, swollen ankles, weight
gain, abdominal pain and digestive disturbances. Several non-nutritive, high intensity sugar
alcohols like sorbitol, mannitol, xylitol, erythritol, maltitol and lactitol are available in the
market for diabetic people due to their low calorie value, low glycemic index with high rate
of controlling blood sugar levels.[12-13] The relative sweetness and nutritive value of various
polyol sugars is given in Table 1.
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Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
Table 1: Relative sweetness and nutritive value of various polyol sugars.
Sugar Alcohol
Relative sweetness
(Sucrose=1)
Xylitol
1.0
Lactitol
0.4
Sorbitol
0.6
Erythritol
0.7
Mannitol
0.5
Maltitol
0.9
Isomalt
0.5
Hydrogenated starch hydrolysates
0.3
XYLITOL AS SUGAR SUBSTITUTE FOR DIABETIC PATIENTS
Xylitol is pentitol sugar (C5H12O5) with sweetening power similar to sucrose but with low
calorie content. This alcoholic pentose sugar is found naturally in many fruits and vegetables
like yellow plum, strawberries, raspberries, cauliflower and lettuce.[14] The glycemic index of
xylitol is low because it is not actively transported through intestinal tract. The high tolerance
of xylitol by diabetics is due to its metabolism in humans by two different pathways, such as
direct absorption (mainly in liver) and indirect metabolism by intestinal bacteria. Both of
these mechanisms of xylitol metabolism are independent to insulin and hence it acts as
promising ideal alternate sweetner for diabetics.[15] Xylitol controls blood glucose, lipid level
and weight control, which are the three important objectives for diabetes management. It is
poorly absorbed by the human digestive system and thus acts as a dietary soluble fiber to
maintain healthy gut flora. Xylitol acts as prebiotic and fermented by the bacteria of large
intestine into low calories short chain fatty acids. These fatty acids are absorbed by small
intestine into blood circulation where they act as source of energy for various metabolic
pathways.[13] Hence, this polyol sugar is very good supplement as sugar for diabetic patients.
PROCESSES FOR PRODUCTION OF XYLITOL
There are mainly three processes for the production of xylitol such as solid liquid extraction,
chemical synthesis and biotechnological methods. Currently, the industrial demand of xylitol
has been met through its synthesis by chemical hydrogenation of xylose at high temperature
and pressure in the presence of catalyst. However, there are many limitations associated with
this chemical process like high process cost, low product yield and hazardous effects on
environment.[16] In the process of solid liquid extraction, xylitol is recovered from the natural
sources (fruits and vegetables), but small percentage present in natural sources is major
hindrance to make this process economical.[17-18] Biotechnological methods are based on
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Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
utilization of microorganisms or purified enzyme for the production of xylitol by utilizing
various agriculutural lignocellulosic waste materials derived from wood, grass, forestry
waste, agricultural residues and municipal solid wastes are center of attraction for researchers
now a days.[19] Candida guilliermondii and Candida tropicalis are two commonly used yeasts
for the production of high yield of xylitol.[20-21] Most of the previous research on production
of xylitol using biotechnological methods has been conducted with whole microbial cells
(mainly yeasts) and recombinant organisms and very little work has been reported with
purified xylose reducatse enzyme. Hence, researchers should focus on enzymatic production
involving recent techniques like protein engineering using bioinformatics tools needs to be
done for economical production of xylitol.
GLOBAL STATUS FOR USE OF XYLITOL
The global market of xylitol is increasing day by day and it is estimated to be USD 1 billion
by 2020.[22] In addition to substituent as sugar, there are various potential applications of
xylitol in different industrial sectors, such as food, pharmaceutical, odontological, cosmetics
and textiles.[23-27] The wide applications of xylitol are due to its unique properties like
sweetening power similar to sucrose, its metabolism independent to insulin, absence of
maillard reaction, negative heat of dissolution, anticariogenicity and antiketogenicity. The
products of xylitol available in the market are Epic-xylitol gums, B-FRESH gums, Tic Tac
“Silvers”, Xylitol (100% pure natural sweetener), Omnii “Theramints”.[28] The major xylitol
market share is dominated by chewing gums applications followed by confectionery and food
sectors. However, a small amount of xylitol is used in the pharmaceuticals and
nutraceuticals.[29] Moreover, most of the xylitol products have been manufactured by USA
and its demend in India is catered through imports. Therefore, there is an utmost need to
focus on biotechnological production of xylitol by utilizing various lignocellulosic waste as
raw materials. The Government of India should need to focus on planning some projects on
economical xylitol production to fulfill the need of xylitol for Indian market by involving
biological methods.
SAFETY ISSUES OF XYLITOL FOR DIABETICS
GRAS (Generally Recognized as Safe) status has been given to xylitol by FDA (Food and
Drug Administration) in 1986. Xylitol has shown very little toxicity issues through various
routes of administration with negative results for tetrogenicity, embryogenicity and
reproductive toxicity for mutagenicity and clastogenicity through in vivo and in vitro
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Balwinder et al. World Journal of Pharmacy and Pharmaceutical Sciences
studies.[30-32] FDA (1986) approved xylitol to be safe for human consumption and joint
FAO/WHO Experts Committee on food additives also recommended safety levels of this
polyol sugar with no need of further toxicological studies. Many previous studies conducted
on rats and diabetic patients confirmed the safety levels of xylitol with no side effects in
relation to carbohydrate and fat metabolism.[33-36]
CONCLUSION
Diabetes is found to be an epidemic disease among the people of India resulting in loss of
national productivity and exchequer at social level. The major factors responsible for this
disease are obesity, food insecurity, illiteracy, poor sanitation, poor glycemic control and
dominance of communicable diseases. Several oral drugs, amylin agonists, glucagon
antagonists, protein tyrosine phosphatase inhibitors, salicylate derivatives and G protein
coupled receptors are used to treat diabetes. However, these treatments are costly and
associated with many side effects like allergic reactions, swollen ankles, weight gain,
abdominal pain and digestive disturbances. Therefore, there is an urgent need to develop
government policies, interventions and public awareness programmed in India to overcome
the spread of this disease in the future generation. As an alternate natural sweetener, xylitol
overcomes the spread of diabetes due to its metabolism independent to insulin. There are
many constrains towards the use of this polyol sugar mainly the cost factor. Therefore, some
biotechnological methods should be developed by utilizing low cost agrowaste material to
increase the yield of xylitol in cost effective manner for its utilization in therapeutic sector.
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... Among various enzymes, xylose reductase (XR) is one of the industrially important enzymes, which catalyzes the conversion of xylose into xylitol [2]. This polyol sugar shows tremendous applications in various industrial sectors like food, cosmetics, therapeutic, odontological, and pharmaceuticals due to its unique properties like sweetening power similar to sucrose, absence of Maillard reaction, low glycemic index, ability to fight against infections, providing cool and fresh sensation in mouth, remineralization of teeth, antiketogenic, anticariogenic, humectants, and emollient properties [3,4]. The present industrial demand of xylitol has been met through the chemical synthesis process, which involves the nickel as a catalyst for the reduction of D-xylose into xylitol using extreme conditions of temperature and pressure. ...
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Xylose reductase (XR), an industrially important enzyme, catalyzes the hydrogenation of xylose into xylitol. Xylitol, a polyol sugar, has tremendous applications in different industries due to its significant properties. XR is mainly produced from yeasts and molds, and limited studies have been reported on bacteria. The present study explores the potential of newly isolated bacteria, i.e., Pseudomonas putida BSX-46 for XR synthesis through process scale-up by tailoring its nutritional and cultural requirements. A simple media containing only four ingredients was designed for the production of XR in a short incubation time of 24 h. A process for pretreatment of rice straw was developed to achieve hydrolysate with a good amount of xylose (140 g/kg of rice straw). The enhanced XR production of 213.14±0.47 IU/mg of cells was achieved at bioreactor level using waste rice straw hydrolysate as compared to 94.26±0.62 IU/mg of cells at flask level. The developed bioprocess using efficient bacterial source and economical raw material would provide a low-cost substitute for XR production from xylose-based agro-waste materials at the industrial level.
... also used in odontological sector for the prevention of dental caries by inhibiting the growth of Streptococcus mutans [28]. The daily intake of xylitol results in reduced risk of dental caries [31,127] and remineralization of caries lesions [74]. The humectant properties of xylitol have also been reported, and therefore, it is used in cosmetic industry in many beauty creams and lotions. ...
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... Xylitol is a five-carbon sugar alcohol, produced commercially by catalytic hydrogenation of xylose [100] found naturally in some fruits and vegetables with fewer calories [121]. Xylitol metabolism is not dependent on insulin; thus, it can be used in the therapeutic sector like sugar substitute for diabetes individuals [122]. Microbial production (from yeast) of xylitol is becoming very attractive because the high-quality product is produced and is costefficient. ...
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... Se han estudiado las condiciones óptimas para la producción de xilitol a partir de xilosa (Carvalheiro et al., 2005;Mussatto y Roberto, 2008). El xilitol y arabitol han sido usados como endulzantes de bebidas, chicles y caramelos que no contienen azúcar, por lo cual ha sido recomendado para diabéticos, también pueden monómeros para la producción de polímeros e intermediarios (Rafiqul et al., 2017;Lugani et al., 2017). ...
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Recently, the utilization of agro-industrial lignocellulosic waste materials has received much attention for the production of value-added products like enzymes, organic acids and biofuels. Microbial-based environment-friendly approaches are receiving greater attention for the management of these waste materials in both developing and developed countries due to the increase in problems associated with industrialization and environmental pollution. Agroindustrial lignocellulosic biomass is renewable, inexpensive and abundant and hence can be used as a unique natural source for the cost-effective and large-scale production of these valuable products. Microbial and enzyme technology is one of the most promising approaches in the field of industrial biotechnology for the production of numerous commercial products. Currently, enzymes are extensively used in various industrial sectors like food, pharmaceutics, odontology, textile, detergent, bioremediation, paper and pulp, and wine and brewery. Many industries focused on the utilization of agro-based wastes containing lignocellulosic material as a substrate for the large-scale production of industrial enzymes through either solid-state or submerged fermentation. However, biomass transport, proper handling and pretreatment methods for delignification are some of the limitations associated with the use of lignocellulosic materials. Recently, there has been a resurgence in the utilization of various agricultural wastes like sugarcane baggase, wheat straw, wheat bran, rice straw, rice bran, corn cobs, corn stover, banana waste, hardwood, softwood, newspaper, office paper, groundnut shell, coffee by-products, sweet sorghum and grasses for the cost-effective production of enzymes with better yield and novel activity, which can help to bring sustainability in the agriculture sector. Further improvements in enzyme technology can be achieved by incorporating desirable characteristics through some latest techniques like in silico characterization, regulation of metabolic flux, recombinant DNA technology and microarray technology. This chapter describes the biotechnological importance of the utilization of lignocellulosic biomass for the production of industrial enzymes.
... Xylitol is a naturally occurring five-carbon sugar alcohol which is 20% sweeter than sucrose, but with 40% the calories. In addition, the metabolism of xylitol is not dependent Fig. 7 3-Hydroxypropionaldehyde and 3-hydroxypropionic acid value-added chemicals on insulin; thus, it is an ideal sugar substitute for people with diabetes (Lugani et al. 2017). ...
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Until recently, most of energy and industrially produced chemicals were derived from fossil fuel-based resources. This along with the continued depletion of finite fossil resources and their attributed adverse environmental impacts, alternatively sourced and more sustainable resources are being pursued as feedstock replacements. Thus, biomass has been identified as an alternate renewable and more sustainable resource as a means to reduce this sector’s dependence on fossil fuel-based resources and to alleviate their environmental impacts. As such, lignocellulosic biomass has been further identified and demonstrated as an abundant renewable resource for the production of biofuels, platform chemicals, and their respective value-added products. This review article provides an overview of the techniques developed for the valorization of biomass in the production of platform chemicals within a biorefinery and the status for commercialization. © 2018 This is a U.S. Government work and not under
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This book covers the applications of fungi used in biorefinery technology. As a great many different varieties of fungal species are available, the text focuses on the various applications of fungi for production of useful products including organic acids (lactic, citric, fumaric); hydrolytic enzymes (amylase, cellulases, xylanases, ligninases, lipases, pectinases, proteases); advanced biofuels (ethanol, single cell oils); polyols (xylitol); single cell protein (animal feed); secondary metabolites; and much more.
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Xylose reductase (EC 1.1.1.21), an aldo-keto reductase enzyme, catalyzes the conversion of xylose into xylitol. It is present in animals, plants, and many microorganisms. In microorganisms, in addition to its production by many fungal (yeasts and molds) cultures, a few members of bacteria such as Corynebacterium sp. and Enterobacter sp. have also been reported to produce NADPH-dependent xylose reductase (XR). In fungi, XR directly converts xylose into xylitol during the metabolism of xylose by using NADH and/or NADPH as coenzyme. The tetrad of amino acids (Tyr, His, Asp, and Lys) at catalytic site is responsible for XR activity. Several attempts have been made to improve XR production using recombinant DNA technology by introducing xylose reductase gene (xyl1) into different fungal strains from other microorganisms for efficient conversion of xylose to xylitol. Site-directed mutagenesis at the catalytic site is another approach to increase the turnover number and catalytic efficiency of XRs. Xylitol is a rare pentol sugar whose global market is increasing at a very fast pace due to its applications in food, cosmetic, odontological, pharmaceutical, and medical sector. The microbial production of xylitol is emerging as a good alternative due to abundance of agriculture waste material. The present chapter will describe the different aspects of fungal XRs including their structural characteristics, sources, production, purification and characterization, immobilization, patent status, and xylitol applications.
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Xylitol is a pentahydroxy sugar-alcohol which exists in a very low quantity in fruits and vegetables (plums, strawberries cauliflower pumpkin). On commercial scale xylitol can be produced by chemical and biotechnological processes. Chemical production is costly and extensive in purification steps. However, biotechnological method utilizes agricultural and forestry wastes which offer the possibilities of economic production of xylitol by reducing required energy. The precursor xylose is produced from agricultural biomass by chemical and enzymatic hydrolysis and can be converted to xylitol primarily by yeast strain. Hydrolysis under acidic condition is the more commonly used practice influenced by various process parameters. Various fermentation process inhibitors are produced during chemical hydrolysis that reduce xylitol production, a detoxification step is therefore necessary. Biotechnological xylitol production is an integral process of microbial species belonging to Candida genus which is influenced by various process parameters such as pH, temperature, time, nitrogen source and yeast extract level. Xylitol has application and potential for food and pharmaceutical industries. It is a functional sweetener as it has prebiotic effects which can reduce blood glucose, triglyceride and cholesterol level. This review describes recent research developments related to bio-production of xylitol from agricultural wastes, application, health and safety issues.
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Xylitol has been used as a substitute for sugar to prevent cavity-causing bacteria, and most studies have focused on its benefits in dental care. Meanwhile, the constituents of red ginseng (RG) are known to be effective in ameliorating the symptoms of influenza virus infection when they are administered orally for 14 days. In this study, we investigated the effect of dietary xylitol on influenza A virus infection (H1N1). We designed regimens containing various fractions of RG (RGs: whole extract, water soluble fraction, saponin and polysaccharide) and xylitol, and combination of xylitol with the RG fractions. Mice received the various combinations orally for 5 days prior to lethal influenza A virus infection. Almost all the mice died post challenge when xylitol or RGs were administered separately. Survival was markedly enhanced when xylitol was administered along with RGs, pointing to a synergistic effect. The effect of xylitol plus RG fractions increased with increasing dose of xylitol. Moreover, dietary xylitol along with the RG water soluble fraction significantly reduced lung virus titers after infection. Therefore, we suggest that dietary xylitol is effective in ameliorating influenza-induced symptoms when it is administered with RG fractions, and this protective effect of xylitol should be considered in relation to other diseases.
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The problem of mass diabetes is steadily increasing everyday. This editorial introduces key issues that need to be addressed to support the effective control of diabetes in India as well as globally. Issues like awareness generation for risk reduction, frequency of monitoring for selected parameters, standards for monitoring chronic complications in patients with diabetes, and current recommended targets of various parameters, amongst others, are presented along with extensions to the vaccinations recommended for diabetic patients.
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Abstract Xylitol, a five-carbon polyalcohol, holds a substantial place in the cure and prevention of a number of diseases. The foremost reason for its lesser usage in day-to-day practice is its cost. The method employed on large scale production of this polyol, i.e. chemical reduction, uses extensive machinery and expensive chemicals thus increasing the basic cost of the sugar. Yield of xylitol by other methods including fermentation and enzymatic production is far less than chemical reduction. We did a literature analysis and briefed out the various experiments carried out till date and concluded on the required studies for improving its production and lowering down its cost.
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This review describes recent research developments on biological conversion of hemicellulosic biomass towards production of xylitol by taking advantage of power of biotechnology. Xylitol is a five-carbon sugar alcohol with established commercial uses in different healthcare sectors and especially as an alternative sweetener for diabetic persons. Xylitol can be synthesized either by chemical hydrogenation of xylose or by fermentation. The precursor xylose is produced from biomass by chemical or enzymatic hydrolysis and can be converted to xylitol primarily by yeast strains which offer the possibilities of economic production by reducing required energy when compared to chemical production. Biomass hydrolysis under an acidic environment is the most commonly used practice and is influenced by various process parameters. Several microbial growth inhibitors are produced during chemical hydrolysis that reduce xylitol production from xylose, a detoxification step is therefore essential. Enzymatic hydrolysis has advantages over chemical conversion although more research is necessary to reduce inhibition due to structural variation from different substrates or plant species. Enzymatic xylitol production is mostly an integral process of microbial species belonging to the Candida genus. Extensive research has been performed to screen for xylitol producing microbial strains as well as to understand microbial metabolism, the xylitol metabolic pathway, cofactor requirements, development of robust recombinant strains, optimization of bioconversion parameters and xylitol production strategies using free and immobilized cells. The imperative role of hydrolysis of xylose containing biomass and subsequent process parameters has major impact on economis of bioconversion. The review identifies ways forward for improved enzymatic xylitol production to compete with current chemical processes.
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Diabetes is an escalating problem in India and has major socio-economic dimensions. Rapid dietary changes coupled with decreased level of physical activity have resulted in increasing obesity and diabetes in rural and semi-urban areas and in urban based people living in resettlement colonies. Increasing risk has also been recorded in those who suffered from poor childhood nutrition, and in rural-to-urban migrants. Social inequity manifests in disparities in socio-economic strata (SES), place of residence, education, gender, level of awareness and affect prevention, care and management. All these population subsets have major socio-economic challenges; low level of awareness regarding diabetes and prevention, inadequate resources, insufficient allotment of healthcare budget and lack of medical reimbursement. Unawareness and delays in seeking medical help leads to complications, resulting in increase in cost of diabetes care many folds. These plunge individuals and households into a vicious cycle of further economic hardship, inadequate management, and premature mortality, resulting in more economic loses. At the societal level these are massive losses to national productivity and exchequer. Overall, there is an immediate need of strengthening the health care delivery system for awareness generation, prevention, early detection, cost-effective management, and rehabilitation with focus on people belonging to the lower SES and women (especially focusing on nutrition before and during pregnancy). Due to enhanced awareness campaign spearheaded through National Program on Prevention of Cardiovascular Disease, Cancer, Diabetes and Stroke (NCPCDS) initiated by Government of India, it is likely that the level of awareness and early detection may increase. This article is protected by copyright. All rights reserved.