Effect of xyloglucan (tamarind seed polysaccharide) on conjunctival cell adhesion to laminin and on corneal epithelium wound healing

Tamarind seed polysaccharide-metformin insert: Higher ocular retention, slow-release, and efficacy against corneal burn

Metformin (MET) can be an alternative therapeutic strategy for managing ocular burn primarily because of its pleiotropic mechanism. Longer retention on the ocular surface and sustained release are necessary to ensure the efficacy of MET for ocular application. Although the high aqueous solubility of MET is good for formulation and biocompatibility, it makes MET prone to high nasolacrimal drainage. This limits ocular residence and may be a challenge in its application. To address this, polymers approved for ophthalmic application with natural origin were analyzed through in silico methods to determine their ability to bind to mucin and interact with MET. An ocular insert of MET (3 mg/6 mm) was developed using a scalable solvent casting method without using preservatives. The relative composition of the insert was 58 ± 2.06 %w/w MET with approximately 14 %w/w tamarind seed polysaccharide (TSP), and 28 %w/w propylene glycol (PG). Its stability was demonstrated as per the ICH Q1A (R2) guidelines. Compatibility, ocular retention, drug release, and other functional parameters were evaluated. In rabbits, efficacy was demonstrated in the 'corneal alkali burn preclinical model'. TSP showed potential for mucoadhesion and interaction with MET. With adequate stability and sterility, the insert contributed to adequate retention of MET (10-12 h) in vivo and slow release (30 h) in vitro. This resulted in significant efficacy in vivo.

Transdermal Delivery of Niacin Through Polysaccharide Films Ameliorates Cutaneous Flushing in Experimental Wistar Rats

BACKGROUND

Niacin, an established therapeutic for dyslipidemia, is hindered by its propensity to induce significant cutaneous flushing when administered orally in its unmodified state, thereby constraining its clinical utility.

OBJECTIVE

This study aimed to fabricate, characterize, and assess the in-vitro and in-vivo effectiveness of niacin-loaded polymeric films (NLPFs) comprised of carboxymethyl tamarind seed polysaccharide. The primary objective was to mitigate the flushing-related side effects associated with oral niacin administration.

METHODS

NLPFs were synthesized using the solvent casting method and subsequently subjected to characterization, including assessments of tensile strength, moisture uptake, thickness, and folding endurance. Surface characteristics were analyzed using a surface profiler and scanning electron microscopy (SEM). Potential interactions between niacin and the polysaccharide core were investigated through X-ray diffraction experiments (XRD) and Fourier transform infrared spectroscopy (FTIR). The viscoelastic properties of the films were explored using a Rheometer. In-vitro assessments included drug release studies, swelling behavior assays, and antioxidant assays. In-vivo efficacy was evaluated through skin permeation assays, skin irritation assays, and histopathological analyses.

RESULTS

NLPFs exhibited a smooth texture with favorable tensile strength and moisture absorption capabilities. Niacin demonstrated interaction with the polysaccharide core, rendering the films amorphous. The films displayed slow and sustained drug release, exceptional antioxidant properties, optimal swelling behavior, and viscoelastic characteristics. Furthermore, the films exhibited biocompatibility and non-toxicity towards skin cells.

CONCLUSION

NLPFs emerged as promising carrier systems for the therapeutic transdermal delivery of niacin, effectively mitigating its flushing-associated adverse effects.

State-of-the-art progress on tamarind seed polysaccharide (Tamarindus indica) and its diverse potential applications, a review with insight

Tamarind seed polysaccharide (TSP) is a biocompatible, non-ionic polymer with antioxidant properties. Its uses include drug delivery, food industry, and wastewater treatment. TSP has various hydroxy functional groups, one of the most favorable sites for graft copolymerization of different monomers. Hence, various chemical methods for TSP modification were developed to satisfy increasing industrial demand. Of particular interest in scientific community are the methods of graft copolymerization because of their ability to alter the physicochemical properties of TSP, including pH sensitivity and the swelling index, leading to improvements in the adsorption efficiency of hazardous heavy metals and dyes from wastewater effluents. Moreover, in recent years, TSP has been used for controlled drug delivery applications due to its unique advantages of high viscosity, broad pH tolerance, non-carcinogenicity, mucoadhesive properties, biocompatibility, and high drug entrapment capacity. In light of the plethora of literature on the topic, a comprehensive review of TSP-based graft copolymers and unmodified and modified TSP important applications is necessary. Therefore, this review comprehensively highlights several synthetic strategies for TSP-grafted copolymers and discusses unmodified and modified TSP potential applications, including cutting-edge pharmaceutical, environmental applications, etc. In brief, its many advantages make TSP-based polysaccharide a promising material for applications in various industries.

Preparation of xyloglucan-grafted poly(N-hydroxyethyl acrylamide) copolymer by free-radical polymerization for in vitro evaluation of human dermal fibroblasts

Xyloglucan is a rigid polysaccharide that belongs to the carbohydrate family. This hemicellulose compound has been widely used in biomedical research because of its pseudoplastic, mucoadhesive, mucomimetic, and biocompatibility properties. Xyloglucan is a polyose with no amino groups in its structure, which also limits its range of applications. It is still unknown whether grafting hydrophilic monomers onto xyloglucan can produce derivatives that overcome these shortcomings. This work aimed to prepare the first copolymers in which N-hydroxyethyl acrylamide is grafted onto tamarind xyloglucan by free-radical polymerization. The biocompatibility of these structures in vitro was evaluated using human dermal fibroblasts. Gamma radiation-induced graft polymerization was employed as an initiator by varying the radiation dose from 5-25 kGy. The structure of the graft copolymer, Xy-g-poly(N-hydroxyethyl acrylamide), was verified by thermal analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The findings indicate that the degree of grafting and the cytotoxicity/viability of the xyloglucan-based copolymer were independent of dose. Notably, the grafted galactoxyloglucan exhibited efficient support for human dermal fibroblasts, showing heightened proliferative capacity and superior migration capabilities compared to the unmodified polymer. This copolymer might have the potential to be used in skin tissue engineering.

Anti-ischemic effect of Tamarindus indica L. seed extract against myocardial hypoxic injury

Background: Ischemic heart disease is a leading cause of death in patients with cardiovascular disease. Natural products containing high antioxidant activity have been used as an alternative therapy to improve the living conditions of patients. In this study, we examine the protective effect of tamarind seed (TS) on myocardial hypoxic injury. Methods: The hypoxia model was mimicked by mineral oil overlayed on H9c2 cardiomyoblasts for 4 h. TS extract was pretreated and administered during the hypoxic condition. Radical scavenging activity of TS extract was measured and exhibited very potent antioxidant activities on 2,2-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Results: TS extract at a concentration of 10 µg/ml significantly reversed the effect of hypoxia-induced cell death and intracellular reactive oxygen species (ROS) production. We also observed hypoxia-induced over-expression of both inflammatory cytokine mRNA and activation of cellular apoptosis. Pretreatment of TS extract significantly reduced hypoxia-induced HIF-1a and pro-inflammatory cytokine production, IL-1b and IL-6. The Western blot analysis for apoptotic regulatory molecules, caspase 3, caspase 8 and Bax proteins, also showed hypoxia injury reversal by TS extract treatment. Conclusions: The results suggest that the anti-ischemic effect of TS extract protects against hypoxia-induced injury and has potential to be an effective alternative therapy for ischemic heart disease and oxidative-damage related disease.

Formulation and Optimal Design of Dioscorea bulbifera and Honey-Loaded Gantrez®/Xyloglucan Hydrogel as Wound Healing Patches

Hydrogel patches are some of the most effective dressings for wound healing. In this study, the Gantrez^® S-97 (Gan)/xyloglucan (XG) hydrogel patches were formulated by using a full central composite design (CCD). The optimized hydrogel patches consisted of 17.78% w/w of Gan and 0.1% w/w of XG. Honey and D. bulbifera extract were loaded in the Gan/XG hydrogel patches. The physical properties of the hydrogel patches, including water content, water absorption, rate of water vapor transmission, and mechanical properties, were examined. The D. bulbifera extract/honey-loaded patch exhibited a higher value of water absorption, tensile strength, and elongation than the honey-loaded patch and the unloaded patch, respectively. The biological activities of the patches were also investigated. All hydrogel patches protected wounds from external bacterial infection. The D. bulbifera extract/honey-loaded patch exhibited stronger antioxidant activity than the honey-loaded patch and the unloaded patch. Besides, all the hydrogel patches with concentrations of 0.5-2.5 mg/mL showed that they were nontoxic to fibroblast cells. The combination of D. bulbifera extract and honey in the patch affected fibroblast proliferation. In addition, all Gan/XG hydrogel patches significantly induced recovery of the scratch area. Therefore, the Gan/XG hydrogel patches could be candidates as wound dressings.

Electrospun polysaccharide scaffolds: wound healing and stem cell differentiation

Irrespective of the labyrinth of fastidiously woven artificial scaffolds, the lack of biocompatibility hampers effective clinical translation, which is the definitive purpose of any biomedical system or device. Hence, the current exploration deals with the fabrication of scaffolds with enhanced bioactivities for wound healing. The methodology used for the fabrication of the scaffolds was electrospinning of the polysaccharide, which is isolated from tamarind seed kernel using the electrospinning process. To improve the antimicrobial activity of the scaffolds, in-house synthesized silver nanoparticles were added to the scaffolds. Wound healing and antimicrobial efficiency of the scaffolds were established in murine models. An insight into the wound healing mechanism was also analyzed using differentiation screening of stem cells grown on scaffolds. The results showed that newly synthesized scaffolds presented excellent wound healing ability along with antimicrobial activity. Furthermore, detailed toxicological evaluations through the histopathology and collagen staining wound sections, the probability of any off-target effects were also ruled out. Differentiation screening showed that adipogenesis was more prominent in cells attached to the scaffolds and markers of adipogenesis were strongly expressed in fluorescent microscopy. Thus we hope that the scaffolds mediate stem cell differentiation in wounds and promote a progressive healing response. Results thus obtained were encouraging and further studies need to embark on to establish the combined role in all aspects studied here.

Rheological Behavior of a New Mucoadhesive Oral Formulation Based on Sodium Chondroitin Sulfate, Xyloglucan and Glycerol

Background: The study aimed at assessing the mucoadhesive properties and the barrier effect of a formulation, labelled as AL2106, containing sodium chondroitin sulfate (ChS), xyloglucan from tamarind seed extract, and glycerol, by evaluating the capacity to adhere to a layer of mucin, the rheological synergism and the barrier effect in comparison to the marketed Esoxx One medical device. AL2106 is a medical device distributed by Alfasigma SpA, Italy with REF FTP57 (Manufacturer: Labomar SpA); it is analogous to Esoxx One medical device: the two products are drinkable solutions that, after swallowing, adhere to the esophageal mucosa, protecting it from the corrosive effect of the gastric acid reflux. AL2106 has been conceived to be better performing in terms of duration of the barrier effect compared to Esoxx One. Methods: The mucoadhesive properties, rheological behavior, buffering capacity against acidity, and film-forming ability with the resultant protecting effect on esophagus mucosa (caffeine permeation test) was compared between the two products. Results: The mucoadhesivity of the formulations was shown in vitro: both remained adherent to a mucin layer, also when the support was rotated by 90°, and when the film layer was washed with water, intended to simulate the washout due to swallowing. AL2106 showed a good buffering efficacy, being able to absorb at least 50% of its weight of 0.03 M HCl while maintaining the pH above 4. The film-forming effect and barrier properties of AL2106 and Esoxx One were confirmed by an in vitro study on reconstructed human esophageal epithelium. A greater film-forming efficacy of AL2106, lasting for at least 5 h, than Esoxx One was observed. Noteworthy, the barrier function of esophageal tissues was shown to be preserved after the application of both formulations. Conclusions: The combination of ChS with the mucoadhesive glycerol-xyloglucan complex and other excipients, which contribute to the barrier effect and to mucoadhesion, contained in AL2106, allowed a longer-lasting protective effect than Esoxx One, proving its effectivity and safety for oral use.

Xyloglucan as green renewable biopolymer used in drug delivery and tissue engineering

Xyloglucan is a mucoadhesive polysaccharide which is extracted from the cell wall of vascular plants. Tamarind seeds are the abundant source of xyloglucan and commercially more popular. It is biocompatible, biodegradable, and nontoxic in nature. It is approved by the FDA for use as a food additive, stabilizing and thickening agent or gelling agent. Recently, many researchers are giving attention to xyloglucan for drug delivery through various routes and regeneration of the number of tissues. However, the findings of tissue regeneration and drug delivery in combination are not collected and represented in a simple and comprehensive way. The aim of this review is to find and represent these missing links. This review presents current researches on xyloglucan in drug delivery and regeneration of tissue.

Novel Xyloglucan Sheet for the Treatment of Deep Wounds: Preparation, Physicochemical Characteristics, and in Vivo Healing Effects

In the present study, a novel wound dressing made of xyloglucan (Xyl)-sucrose (Suc) hydrogel was developed for the treatment of deep wounds including pressure ulcers. The dressing was prepared by casing an aqueous solution of Xyl and sugar and then warming, and a hydrogel sheet was obtained. The in vitro characteristics of these sheets, such as their strength, extensibility, water content, adhesion potential, and water absorption, were examined. The strength, Young's modulus, and adhesion strength of the sheets were greater when they had a lower water content. Furthermore, adhesion and gradual water absorbability were similar to those of commercial dressings. These in vitro features suggest that Xyl sheets possess the physicochemical properties required for wound dressings. In the in vivo experiment, a Xyl sheet made from a mixture of 3.0% (w/v) Xyl solution and 33.3% (w/w) Suc, which displayed moderate strength and water content, was selected and compared with gauze, commercial polyurethane film, and Xyl/Suc (1 : 2) hydrogel using a rat deep wound model caused by serious frostbite. Wound healing rates based on reductions in wound areas were the best in the order of the sheet > hydrogel > commercial film > gauze. The sheet resulted in better wound surface states than the other preparations by improving the conditions. Thus, the potential applicability of Xyl sheets to the treatment of deep wounds was demonstrated.

Rheological properties and efficacy of the formulation of hyaluronic acid with tamarind seed polysaccharide for arthritis

BACKGROUND

Tamarind seed polysaccharide (TSP) is used as a texturizing agent and a thickener in food and pharmaceutical products. There are no publications describing the addition of TSP to intra-articular injection formulations for arthritis.

OBJECTIVE

The purpose of this study was to investigate the rheology and efficacy of the formulation of TSP with hyaluronic acid (HA) as a new material for injection for arthritis.

METHODS

We investigated the viscoelastic properties of formulations of HA and TSP as potential lubricants for arthritis, and tested the improvement of right/left paw weight distribution in monosodium iodoacetate-induced arthritis in the rat.

RESULTS

HA formulations with 3% and 4% TSP showed improved rheological characteristics and were protected against changes induced by heat sterilization. Addition of TSP also reduced pain in the arthritis model, as evidenced by normalization of the distribution of paw weight.

CONCLUSIONS

TSP is a potential material as a substitute for HA or in combination with HA for intra-articular injection for arthritis.

Xyloglucan, a Plant Polymer with Barrier Protective Properties over the Mucous Membranes: An Overview

Disruption of the epithelial barrier function has been recently associated with a variety of diseases, mainly at intestinal level, but also affecting the respiratory epithelium and other mucosal barriers. Non-pharmacological approaches such as xyloglucan, with demonstrated protective barrier properties, are proposed as new alternatives for the management of a wide range of diseases, for which mucosal disruption and, particularly, tight junction alterations, is a common characteristic. Xyloglucan, a natural polysaccharide derived from tamarind seeds, possesses a "mucin-like" molecular structure that confers mucoadhesive properties, allowing xyloglucan formulations to act as a barrier capable of reducing bacterial adherence and invasion and to preserve tight junctions and paracellular flux, as observed in different in vitro and in vivo studies. In clinical trials, xyloglucan has been seen to reduce symptoms of gastroenteritis in adults and children, nasal disorders and dry eye syndrome. Similar mucosal protectors containing reticulated proteins have also been useful for the treatment of irritable bowel syndrome and urinary tract infections. The role of xyloglucan in other disorders with mucosal disruption, such as dermatological or other infectious diseases, deserves further research. In conclusion, xyloglucan, endowed with film-forming protective barrier properties, is a safe non-pharmacological alternative for the management of different diseases, such as gastrointestinal and nasal disorders.

Rufloxacin Eyedrops: Effect of Different Formulations on Ocular Pharmacokinetics in Rabbits

PURPOSE

To evaluate the aqueous humor pharmacokinetics of rufloxacin in rabbits after topical administration of different formulations, and to individuate the ones showing the best pharmacokinetic profile.

METHODS

Six formulations were instilled in rabbit eyes: two pH 7.2 suspensions of non-salified rufloxacin base, or zwitterion (RUF), one of which was viscosized with tamarind seed polysaccharide (TSP); two pH 7.2 solutions of RUF obtained using hydroxypropyl-beta-cyclodextrin (CD), one of which was viscosized with TSP; and two pH 5.0 solutions of rufloxacin hydrochloride (RUF-HCl ), one of which was viscosized with TSP. At different times after administration, samples of aqueous humor were withdrawn and analyzed by high-pressure liquid chromatography. The main pharmacokinetic parameters of RUF in the aqueous humor produced by the different formulations were calculated and statistical differences were assessed.

RESULTS

The best results, in terms of aqueous humor bioavailability, were observed with two TSP-viscosized formulations: a solution of the hydrochloride (TSP/RUF-HCl) and a suspension of the base (TSP/RUF), followed by the non-viscosized solution of RUF-HCl. The formulations containing CD-solubilized RUF were much less effective.

CONCLUSIONS

The present data confirm the significant availability-enhancing properties of tamarind seed polysaccharide, and indicate that solubilization of RUF with hydroxypropyl-beta-cyclodextrin (CD/RUF) results in decreased drug availability with respect to standard formulations. Two of the TSP-viscosized formulations (RUF suspension and RUF-HCl solution) produced aqueous humor RUF concentrations in the range of activity against Enterobacteriaceae and Pseudomonas aeruginosa, thus warranting further studies on applications of rufloxacin in ocular therapy.

Chromolaena odorata: A neglected weed with a wide spectrum of pharmacological activities (Review)

The study of wound‑healing plants has acquired an interdisciplinary nature with a systematic investigational approach. Several biochemicals are involved in the healing process of the body, including antioxidants and cytokines. Although several pharmaceutical preparations and formulations are available for wound care and management, it remains necessary to search for efficacious treatments, as certain current formulations cause adverse effects or lack efficacy. Phytochemicals or biomarkers from numerous plants suggest they have positive effects on different stages of the wound healing process via various mechanisms. Several herbal medicines have displayed marked activity in the management of wounds and various natural compounds have verified in vivo wound healing potential, and can, therefore, be considered as potential drugs of natural origin. Chromolaena odorata (L.) R.M. King and H. Robinson is considered a tropical weed. However, it exhibits anti‑inflammatory, antipyretic, analgesic, antimicrobial, cytotoxic and numerous other relevant medicinal properties on an appreciable scale, and is known in some parts of the world as a traditional medicine used to treat various ailments. To understand its specific role as nature's gift for healing wounds and its contribution to affordable healthcare, this plant must be scientifically assessed based on the available literature. This review aims to summarize the role of C. odorata and its biomarkers in the wound healing activities of biological systems, which are crucial to its potential future drug design, development and application for the treatment of wounds.

Conjunctivally Applied BDNF Protects Photoreceptors from Light-Induced Damage

PURPOSE

To test whether the topical eye treatment with BDNF prevents the effects of continuous light exposure (LE) in the albino rat retina.

METHODS

Two groups of albino rats were used. The first group of rats received an intraocular injection of BDNF (2 μL, 1 μg/μL) before LE, while the second group was treated with one single drop of BDNF (10 μL, 12 μg/μL) dissolved in different types of solutions (physiological solution, the polysaccharide fraction of Tamarind gum, TSP, and sodium carboxy methyl cellulose), at the level of conjunctival fornix before LE. The level of BDNF in the retina and optic nerve was determined by enzyme-linked immunosorbent assay. We recorded the flash electroretinogram (fERG) in dark adapted rats 1 week after LE. At the end of the recording session, the retinas were removed and labeled so that the number of photoreceptors nuclear rows and thickness of the outer nuclear layer was analyzed.

RESULTS

Intravitreal injection of BDNF before LE prevented fERG impairment. Different ophthalmic preparations were used for topical eye application; the TSP resulted the most suitable vehicle to increase BDNF level in the retina and optic nerve. Topical eye application with BDNF/TSP before LE partially preserved both fERG response and photoreceptors.

CONCLUSIONS

Topical eye treatment with BDNF represents a suitable, noninvasive tool to increase the retinal content of BDNF up to a level capable of exerting neuroprotection toward photoreceptors injured by prolonged LE.

TRANSLATIONAL RELEVANCE

A collyrium containing BDNF may serve as an effective, clinically translational treatment against retinal degeneration.

Tamarind Seed Xyloglucans Promote Proliferation and Migration of Human Skin Cells through Internalization via Stimulation of Proproliferative Signal Transduction Pathways

Xyloglucans (XGs) of Tamarindus indica L. Fabaceae are used as drug vehicles or as ingredients of cosmetics. Two xyloglucans were extracted from T. indica seed with cold water (TSw) and copper complex precipitation (TSc). Both were analyzed in regard to composition and influence on cell viability, proliferation, cell cycle progression, migration, MAPK phosphorylation, and gene expression of human skin keratinocytes (NHEK and HaCaT) and fibroblasts (NHDF) in vitro. TSw and TSc differed in molecular weight, rhamnose content, and ratios of xylose, arabinose, galactose, and glucose. Both XGs improved keratinocytes and fibroblast proliferation, promoted the cell cycle, and stimulated migration and intracellular enzyme activity of NHDF after endosomal uptake. Only TSw significantly enhanced HaCaT migration and extracellular enzyme activity of NHDF and HaCaT. TSw and TSc predominantly enhanced the phosphorylation of molecules that referred to Erk signaling in NHEK. In NHDF parts of the integrin signaling and SAPK/JNK pathway were affected. Independent of cell type TSw marginally regulated the expression of genes, which referred to membrane proteins, cytoskeleton, cytokine signaling, and ECM as well as to processes of metabolism and transcription. Results show that T. indica xyloglucans promote skin regeneration by a direct influence on cell proliferation and migration.

Dietary roles of non-starch polysaccharides in human nutrition: a review

Nonstarch polysaccharides (NSPs) occur naturally in many foods. The physiochemical and biological properties of these compounds correspond to dietary fiber. Nonstarch polysaccharides show various physiological effects in the small and large intestine and therefore have important health implications for humans. The remarkable properties of dietary NSPs are water dispersibility, viscosity effect, bulk, and fermentibility into short chain fatty acids (SCFAs). These features may lead to diminished risk of serious diet related diseases which are major problems in Western countries and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, colo-rectal cancer, inflammatory bowel disease, breast cancer, tumor formation, mineral related abnormalities, and disordered laxation. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalize blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and Type 2 diabetes. Moreover, a major proportion of dietary NSPs escapes the small intestine nearly intact, and is fermented into SCFAs by commensal microflora present in the colon and cecum and promotes normal laxation. Short chain fatty acids have a number of health promoting effects and are particularly effective in promoting large bowel function. Certain NSPs through their fermented products may promote the growth of specific beneficial colonic bacteria which offer a prebiotic effect. Various modes of action of NSPs as therapeutic agent have been proposed in the present review. In addition, NSPs based films and coatings for packaging and wrapping are of commercial interest because they are compatible with several types of food products. However, much of the physiological and nutritional impact of NSPs and the mechanism involved is not fully understood and even the recommendation on the dose of different dietary NSPs intake among different age groups needs to be studied.

Arabinogalactan as active compound in the management of corneal wounds: in vitro toxicity and in vivo investigations on rabbits

Purpose: Aims of the present investigation were to prove that natural polysaccharide arabinogalactan (AG) is well tolerated after ocular administration and exerts a high restoring effect on corneal epithelium abrasions.

Materials and Methods: AG interactions with corneal cells, as well as its effect on their proliferation, were evaluated employing rabbit corneal epithelial cell cultures. The effects due to the presence of benzalkonium chloride (BAK) were also studied on cell cultures, ex vivo on rabbit isolated corneas, evaluating the hydration level, and on the healing rate of experimental corneal wounds in rabbits. Furthermore, the healing process of corneal lesions treated with an experimental 5.0% AG solution was studied and compared with those obtained applying solutions of hyaluronic acid and tamarind seed polysaccharide, both chosen as a reference by virtue of their well-known adjuvant properties on corneal trophism; the study was carried out by light and transmission electron microscopy.

Results: BAK showed toxic effects on corneal epithelium in all experiments. AG proved to stimulate the growth of the corneal epithelial cells by interacting at the level of the cell plasma membrane. The microscopy observations of the epithelial surface of AG-treated damaged corneas revealed a well-restored and histologically organized ultrastrucrure characterized by fully formed microvilli and glycocalyx; the healing process resulted faster with respect to spontaneously recovered untreated corneas.

Conclusion: Our results suggest that AG can interact with corneal epithelial cells without any toxic side effect; moreover, it proved to stimulate cell proliferation, thus promoting tissue re-epithelial-ization and reorganization just 48 hr post-wounding.

Sensory properties and consumer acceptance of sweet tamarind varieties grown in Thailand

BACKGROUND

Sweet tamarind is a major edible fruit and flavoring ingredient particularly in south-east and southern Asia. Little research has focused on the fruit and almost nothing is known of its particular sensory properties. The aims of this research were to develop a lexicon for describing sweet tamarind, to compare varieties grown in Thailand, determine if orchard impacts sensory properties, and determine consumer acceptance of the varieties.

RESULTS

A descriptive sensory lexicon of 25 terms was developed and six varieties were grouped into three clusters based on their sensory properties. The clusters appear to represent varieties that differ in their dark fruity notes and firm, fibrous texture. Generally, the orchard in which the plants were grown had little effect on sensory properties. In general, Sithong was liked by consumers along with Kunthee and Pragaithong. Intapalum was liked less but one small segment of consumers disliked Sithong and liked the Intapalum variety more.

CONCLUSIONS

This research provides a foundation for further sensory and consumer research on sweet tamarind varieties by providing the initial data on the sensory properties of sweet tamarind, a lexicon that can be used for future research, and information on the consumer acceptance of tamarind varieties.

Enhancing neurite outgrowth from primary neurones and neural stem cells using thermoresponsive hydrogel scaffolds for the repair of spinal cord injury

In this study, thermoresponsive xyloglucan hydrogel scaffolds were investigated as candidates for neural tissue engineering of the spinal cord. The hydrogels were optimized to provide similar mechanical properties to that of native spinal cord, although also being functionalized through the immobilization of poly-D-lysine to promote neurone adhesion and neurite outgrowth. Under 2D and 3D culture conditions, xyloglucan scaffolds supported the differentiation of primary cortical neurones. Furthermore, functionalization provided a means of controlling and optimizing the cell diameter, number, migration and the neurite density, and the direction of growth. The interaction of neural stem cells (NSCs) was also investigated on the xyloglucan scaffolds in vitro. The survival of the NSCs and the axonal extensions on the scaffolds were similar to that of the primary cortical neurones. These findings suggest that xyloglucan-based materials are suitable for providing a neurotrophic milieu.

Enhanced affinity of ketotifen toward tamarind seed polysaccharide in comparison with hydroxyethylcellulose and hyaluronic acid: a nuclear magnetic resonance investigation

Nuclear magnetic resonance (NMR) spectroscopy demonstrated that, in aqueous solution, ketotifen fumarate bound more strongly to tamarind seed polysaccharide (TSP) than to hydroxyethylcellulose or hyaluronic acid. Results were confirmed by dynamic dialysis technique.

Ethnopharmacological approaches to wound healing--exploring medicinal plants of India

India has a rich tradition of plant-based knowledge on healthcare. A large number of plants/plant extracts/decoctions or pastes are equally used by tribals and folklore traditions in India for treatment of cuts, wounds, and burns. The present review thus attempts to analyze the ethnobotanical knowledge base for treatment of cuts and wounds which includes a usage of plants, methods employed by tribals and folklore practices prevailing in India. Pharmacological reports available on Indian medicinal plants employing various wound healing models and its underlying molecular mechanism, wherever available, has also been briefly reviewed. This pharmacological validation on Indian medicinal plants is very limited and a large number of plants used in tribal and folklore with enormous potential have not been validated for their wound healing activity. This review therefore attempts to bridge the lacunae in the existing literature and offers immense scope for researchers engaged in validation of the traditional claims and development of safe and effective and globally accepted herbal drugs for cuts and wounds.

Carboxymethyl β-glucan Binds to Corneal Epithelial Cells and Increases Cell Adhesion to Laminin and Resistance to Oxidative Stress

PURPOSE

Polysaccharides are frequently used as viscoelastic agents to improve pharmacokinetics of ophthalmic preparations. Recently, polysaccharides from yeast cell walls such as beta-glucans have emerged as bioactive molecules endowed with immunomodulatory and cytoprotective properties. In this study, we investigated the effects of carboxymethyl beta-glucan (CMG), a water-soluble derivative of yeast beta-glucan, on cultured rabbit corneal epithelial cells.

METHODS

We developed a fluorescein-labeled CMG to visualize its binding to corneal cells by means of digital microscopy and image deconvolution. The effects of CMG on adhesion and survival of corneal epithelial cells exposed to noxious stimuli were also studied.

RESULTS

CMG binds defined regions scattered throughout the body of corneal cells, suggesting binding specificity. Tridimensional reconstruction of fluorescence shows that binding is localized mainly at the plasma and nuclear membranes. Interestingly, CMG binding is highly represented at the level of focal adhesion of cells spreading onto laminin. Accordingly, CMG promotes adhesion of corneal epithelial cells to laminin without affecting their proliferation rate. CMG also protects cells from oxidative stress-dependent cell death, being ineffective in preventing ultraviolet B cytotoxicity.

CONCLUSIONS

Data show that CMG dynamically binds to corneal epithelial cells, promoting cell adhesion and resistance to oxidative stress.

A mucoadhesive polymer extracted from tamarind seed improves the intraocular penetration and efficacy of rufloxacin in topical treatment of experimental bacterial keratitis

Bacterial keratitis is a serious infectious ocular disease requiring prompt treatment to prevent frequent and severe visual disabilities. Standard treatment of bacterial keratitis includes topical administration of concentrated antibiotic solutions repeated at frequent intervals in order to reach sufficiently high drug levels in the corneal tissue to inhibit bacterial growth. However, this regimen has been associated with toxicity to the corneal epithelium and requires patient hospitalization. In the present study, a mucoadhesive polymer extracted from tamarind seeds was used for ocular delivery of 0.3% rufloxacin in the treatment of experimental Pseudomonas aeruginosa and Staphylococcus aureus keratitis in rabbits. The polysaccharide significantly increased the intra-aqueous penetration of rufloxacin in both infected and uninfected eyes. Rufloxacin delivered by the polysaccharide reduced P. aeruginosa and S. aureus in the cornea at a higher rate than that obtained by rufloxacin alone. In particular, use of the polysaccharide allowed a substantial reduction of S. aureus in the cornea to be achieved even when the time interval between drug administrations was extended. These results suggest that the tamarind seed polysaccharide prolongs the precorneal residence times of antibiotics and enhances drug accumulation in the cornea, probably by reducing the washout of topically administered drugs. The tamarind seed polysaccharide appears to be a promising candidate as a vehicle for the topical treatment of bacterial keratitis.

The polysaccharide from Tamarindus indica (TS-polysaccharide) protects cultured corneal-derived cells (SIRC cells) from ultraviolet rays

The aim of this work was to investigate the possible protective effect of a new viscosising agent, TS-polysaccharide, on corneal-derived cells (SIRC) exposed to ultraviolet-B rays. To verify this, SIRC cells were first exposed, in the absence or in the presence of TS-polysaccharide (1% w/v), for 9 s at the UV-B source and then post-incubated for 45 min at 37 degrees C. After this period the hydrogen peroxide (H(2)O(2)) accumulated in the medium and the concentration of 8-hydroxy-2'-deoxy-guanosine (8-OHdG) in cell DNA was measured. In addition, the amount of (3)H-methyl-thymidine incorporated in cellular DNA was evaluated after 18 h from irradiation. Our results show that cells exposed to UV-B rays accumulate H(2)O(2), and have higher levels of 8OHdG and a lower amount of (3)H-methyl-thymidine incorporated in DNA than control cells. In the presence of TS-polysaccharide, the H(2)O(2) and 8-OHdG accumulation, and the (3)H-methyl-thymidine incorporation were significantly reduced with respect to the values measured in cells exposed in the absence of the polysaccharide. We propose a protective role of the polysaccharide in reducing UV-B derived DNA damage to eye cells. This finding could be of some clinical importance when the polysaccharide is used as a delivery system for ophthalmic preparations.