The Influence of Oxidized Imino-Allantoin in the Presence of OXOG on Double Helix Charge Transfer: A Theoretical Approach.

The genome is continuously exposed to a variety of harmful factors that result in a significant amount of DNA damage. This article examines the influence of a multi-damage site containing oxidized imino-allantoin (OXIa) and 7,8-dihydro-8-oxo-2'-deoxyguanosine (OXOdG) on the spatial geometry, electronic properties, and ds-DNA charge transfer. The ground stage of a d[A1OXIa2A3OXOG4A5]*d[T5C4T3C2T1] structure was obtained at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the condensed phase, with the energies obtained at the M06-2X/6-31++G** level. The non-equilibrated and equilibrated solvent-solute interactions were also considered. Theoretical studies reveal that the radical cation prefers to settle on the OXOG moiety, irrespective of the presence of OXIa in a ds-oligo. The lowest vertical and adiabatic ionization potential values were found for the OXOG:::C base pair (5.94 and 5.52 [eV], respectively). Conversely, the highest vertical and adiabatic electron affinity was assigned for OXIaC as follows: 3.15 and 3.49 [eV]. The charge transfers were analyzed according to Marcus' theory. The highest value of charge transfer rate constant for hole and excess electron migration was found for the process towards the OXOGC moiety. Surprisingly, the values obtained for the driving force and activation energy of electro-transfer towards OXIa2C4 located this process in the Marcus inverted region, which is thermodynamically unfavorable. Therefore, the presence of OXIa can slow down the recognition and removal processes of other DNA lesions. However, with regard to anticancer therapy (radio/chemo), the presence of OXIa in the structure of clustered DNA damage can result in improved cancer treatment outcomes.

Targeted Isolation of Anti-inflammatory Lignans from Justicia aequilabris by Molecular Networking Approach.

Herein, the isolation of secondary metabolites from the aerial parts of Justicia aequilabris guided by HPLC-MSn and molecular networking analyses is reported. Twenty-two known compounds were dereplicated. Three new lignans (aequilabrines A-C (1-3)) and three known compounds (lariciresinol-4'-O-ß-glucose (4), roseoside (5), and allantoin (6)) were obtained. The anti-inflammatory activity of compounds 1-3 was evaluated in vitro by inhibiting the nitric oxide production (NO) and pro-inflammatory activity on the cytokine IL-1ß. Compounds 2 and 3 showed significant inhibitory activity against NO production, with IC50 values of 9.1 and 7.3 µM, respectively. The maximum inhibition of IL-1ß production was 23.5% (1), 27.3% (2), and 32.5% (3).

Nanopore Analysis of the 5-Guanidinohydantoin to Iminoallantoin Isomerization in Duplex DNA.

In DNA, guanine oxidation yields diastereomers of 5-guanidinohydantoin (Gh) as one of the major products. In nucleosides and single-stranded DNA, Gh is in a pH-dependent equilibrium with its constitutional isomer iminoallantoin (Ia). Herein, the isomerization reaction between Gh and Ia was monitored in duplex DNA using a protein nanopore by measuring the ionic current when duplex DNA interacts with the pore under an electrophoretic force. Monitoring current levels in this single-molecule method proved to be superior for analysis of population distributions in an equilibrating mixture of four isomers in duplex DNA as a function of pH. The results identified Gh as a major isomer observed when base paired with A, C, or G at pH 6.4-8.4, and Ia was a minor isomer of the reaction mixture that was only observed when the pH was >7.4 in the duplex DNA context. The present results suggest that Gh will be the dominant isomer in duplex DNA under physiological conditions regardless of the base-pairing partner in the duplex.

Effects of Rhizome Extract of Dioscorea batatas and Its Active Compound, Allantoin, on the Regulation of Myoblast Differentiation and Mitochondrial Biogenesis in C2C12 Myotubes.

With the aging process, a loss of skeletal muscle mass and dysfunction related to metabolic syndrome is observed in older people. Yams are commonly use in functional foods and medications with various effects. The present study was conducted to investigate the effects of rhizome extract of Dioscorea batatas (Dioscoreae Rhizoma, Chinese yam) and its bioactive compound, allantoin, on myoblast differentiation and mitochondrial biogenesis in skeletal muscle cells. Yams were extracted in water and allantoin was analyzed by high performance liquid chromatography (HPLC). The expression of myosin heavy chain (MyHC) and mitochondrial biogenesis-regulating factors, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), sirtuin-1 (Sirt-1), nuclear respiratory factor-1 (NRF-1) and transcription factor A, mitochondrial (TFAM), and the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) were determined in C2C12 myotubes by reverse transcriptase (RT)-polymerase chain reaction (RT-PCR) or western blot. The glucose levels and total ATP contents were measured by glucose consumption, glucose uptake and ATP assays, respectively. Treatment with yam extract (1 mg/mL) and allantoin (0.2 and 0.5 mM) significantly increased MyHC expression compared with non-treated myotubes. Yam extract and allantoin significantly increased the expression of PGC-1α, Sirt-1, NRF-1 and TFAM, as well as the phosphorylation of AMPK and ACC in C2C12 myotubes. Furthermore, yam extract and allantoin significantly increased glucose uptake levels and ATP contents. Finally, HPLC analysis revealed that the yam water extract contained 1.53% of allantoin. Yam extract and allantoin stimulated myoblast differentiation into myotubes and increased energy production through the upregulation of mitochondrial biogenesis regulators. These findings indicate that yam extract and allantoin can help to prevent skeletal muscle dysfunction through the stimulation of the energy metabolism.

Chemiluminescence of Lucigenin-Allantoin and Its Application for the Detection of Allantoin.

Allantoin has been reported as a promising biomarker for monitoring of oxidative stress in humans and widely utilized in a variety of topical pharmaceuticals and cosmetics. Currently, the detection of allantoin is achieved by using chromatographic coupled techniques, which needs sample pre-extraction, derivatization, complex matrixes, and expensive instrumentation. Herein we report both the intense chemiluminescence of allantoin with lucigenin and the chemiluminescent detection of allantoin for the first time. The lucigenin-allantoin system demonstrated chemiluminescence emission intensity 17 times higher than that of the classic lucigenin-hydrogen peroxide system. Based on this fascinating phenomenon, a novel chemiluminescence method has been developed for the sensitive and selective allantoin determination with the combination of flow injection analysis. This method shows a linear calibration curve in the range 0.1-3000 µM with a detection limit (3σ/s) of 0.03 µM. Moreover, it was successfully utilized for the determination of allantoin in human eye drop and real urine samples after simple dilution with water. It shows excellent recoveries in the range 94.0-101.7%, and each measurement takes a very short time. This method exhibits potential advantages in the form of simplicity, rapidity, sensitivity, selectivity, and low cost. Allantoin could be an effective candidate for constructing new chemiluminescence systems, and it may provide a broad range of sensing applications.

A Trivalent Enzymatic System for Uricolytic Therapy of HPRT Deficiency and Lesch-Nyhan Disease.

PURPOSE: Because of the evolutionary loss of the uricolytic pathway, humans accumulate poorly soluble urate as the final product of purine catabolism. Restoration of uricolysis through enzyme therapy is a promising treatment for severe hyperuricemia caused by deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT). To this end, we studied the effect of PEG conjugation on the activity and stability of the enzymatic complement required for conversion of urate into the more soluble (S)-allantoin. METHODS: We produced in recombinant form three zebrafish enzymes required in the uricolytic pathway. We carried out a systematic study of the effect of PEGylation on the function and stability of the three enzymes by varying PEG length, chemistry and degree of conjugation. We assayed in vitro the uricolytic activity of the PEGylated enzymatic triad. RESULTS: We defined conditions that allow PEGylated enzymes to retain native-like enzymatic activity even after lyophilization or prolonged storage. A combination of the three enzymes in an appropriate ratio allowed efficient conversion of urate to (S)-allantoin with no accumulation of intermediate metabolites. CONCLUSIONS: Pharmaceutical restoration of the uricolytic pathway is a viable approach for the treatment of severe hyperuricemia.

The Structure and Function of a Microbial Allantoin Racemase Reveal the Origin and Conservation of a Catalytic Mechanism.

The S enantiomer of allantoin is an intermediate of purine degradation in several organisms and the final product of uricolysis in nonhominoid mammals. Bioinformatics indicated that proteins of the Asp/Glu racemase superfamily could be responsible for the allantoin racemase (AllR) activity originally described in Pseudomonas species. In these proteins, a cysteine of the catalytic dyad is substituted with glycine, yet the recombinant enzyme displayed racemization activity with a similar efficiency (kcat/KM ≈ 5 × 104 M-1 s-1) for the R and S enantiomers of allantoin. The protein crystal structure identified a glutamate residue located three residues downstream (E78) that can functionally replace the missing cysteine; the catalytic role of E78 was confirmed by site-directed mutagenesis. Allantoin can undergo racemization through formation of a bicyclic intermediate (faster) or proton exchange at the chiral center (slower). By monitoring the two alternative mechanisms by 13C and 1H nuclear magnetic resonance, we found that the velocity of the faster reaction is unaffected by the enzyme, whereas the velocity of the slower reaction is increased by 7 orders of magnitude. Protein phylogenies trace the origin of the racemization mechanism in enzymes acting on glutamate, a substrate for which proton exchange is the only viable reaction mechanism. This mechanism was inherited by allantoin racemase through divergent evolution and conserved in spite of the substitution of catalytic residues.

Solid lipid nanoparticles containing copaiba oil and allantoin: development and role of nanoencapsulation on the antifungal activity.

The aim of this work was to develop solid lipid nanoparticles (SLN) containing copaiba oil with and without allantoin (NCOA, NCO, respectively) and to evaluate their antifungal activity. Nanoparticle suspensions were prepared using a high homogenisation technique and characterised by dynamic light scattering, laser diffraction, nanoparticle tracking analysis, multiple light scattering analysis, high-pressure liquid chromatography, pH and rheology. The antifungal activities of the formulations were tested in vitro against the emergent yeasts Candida krusei and Candida parapsilosis, and the fungal pathogens of human skin Trichophyton rubrum and Microsporum canis. The dynamic light scattering analysis showed z-average diameters (intensity) between 118.63 ± 8.89 nm for the nanoparticles with both copaiba oil and allantoin and 126.06 ± 9.84nm for the nanoparticles with just copaiba oil. The D[4,3] determined by laser diffraction showed similar results of 123 ± 1.73 nm for the nanoparticles with copaiba oil and allantoin and 130 ± 3.6 nm for the nanoparticles with copaiba oil alone. Nanoparticle tracking analysis demonstrated that both suspensions had monomodal profiles and consequently, the nanoparticle populations were homogeneous. This analysis also corroborated the results of dynamic light scattering and laser diffraction, exhibiting a smaller mean diameter for the nanoparticles with copaiba oil and allantoin (143 nm) than for the nanoparticles with copaiba oil (204 nm). The physicochemical properties indicated that the dispersions were stable overtime. Rheology evidenced Newtonian behaviour for both suspensions. Antifungal susceptibility showed a MIC90 of 125 µg/mL (nanoparticles with copaiba oil) and 7.8 µg/mL (nanoparticles with copaiba oil and allantoin) against C. parapsilosis. The nanoparticles with copaiba oil and the nanoparticles with copaiba oil and allantoin presented a MIC90 of 500 µg/mL and 250 µg/mL, respectively, against C. krusei. The MIC90 values were 500 µg/mL (nanoparticles with copaiba oil) and 1.95 µg/mL (nanoparticles with copaiba oil and allantoin) against T. rubrum. Against M. canis, the nanoparticles with copaiba oil and allantoin had a MIC9 of 1.95 µg/mL. In conclusion, nanoencapsulation improved the antifungal activity of copaiba oil, which was enhanced by the presence of allantoin. The MICs obtained are comparable to those of commercial products and can represent promising therapeutics for cutaneous infections caused by yeasts and dermatophytes.

[Research on Breeding of Dioscorea opposita cv. Tiegun].

OBJECTIVE: To breeding the new varieties Dioscorea opposita cv. Tiegun with the best comprehensive properties. METHODS: Seven new Dioscorea opposita. cv. Tiegun cultivars were screened by space mutation breeding of Dioscorea opposita cv. Tiegun bulbils. Yield,allantoin content,water soluble extractive and the resistance of these seven cultivars were compared with the main cultivar Dioscorea opposita cv. Tiegun( CK). Meanwhile, the nutrition quality of new cultivars No. 6 and No. 10 were compared with the main cultivar. RESULTS: (1) The fresh weight per plant ranked in the order as follows: No. 6 > No. 10 > No. 4 > No. 9 > No. 1 > CK > No. 2 > No. 8. The drying rate ranked in the order as follows: No. 2 > No. 10 > No. 9 > No. 6 > No. 8 > CK > No. 1 > No. 4. Dry weight per plant ranked in the order as follows: No. 10 > No. 9 > No. 6 > No. 2 > No. 1 > CK > No. 4 > No. 8. The fresh weight per plant, drying rate and dry weight per plant of No. 6 and No. 10 were higher than the main cultivar. (2) The allantoin content ranked in the order as follows: No. 6 > No. 4 > No. 10 > CK > No. 9 > No. 8 > No. 2 > No. 1. (3) The water soluble extractive contents ranked in the order as follows: No. 6 > No. 2 > No. 4 > No. 10 > No. 1 > CK > No. 9 > No. 8. The water soluble extractive content of No. 6 was higher than No. 10 and the main cultivar. (4) No. 10 had the best taste of dry, soft, sweet and fragrant, No. 6 had the taste of dry, floury and hard, and No. 9 had the taste of dry and crisp. (5) No. 6 had the strongest resistance to Gloeosporium pestis and Cykindrosporium dioscoreae; No. 10 had a middle resistance to Gloeosporium pestis and a strong resistance to Cykindrosporium dioscoreae; and the main cultivar had a middle degree of being prone to Gloeosporium pestis and a middle resistance to Cykindrosporium dioscoreae. (6) The content of starch, reducing sugar, protein and ash in No. 6 and No. 10 were higher than that of the main cultivar,while the content of water in No. 6 and No. 10 were lower,which indicated that the nutrition quality of No. 6 and No. 10 is better than the main cultivar. CONCLUSION: The new cultivar No. 10 is suitable for popularizing as a new variety of edible Dioscorea opposita cv. Tiegun. The new cultivar No. 6 is suitable for popularizing as a new variety of medicinal Dioscorea opposita cv. Tiegun.

E. coli allantoinase is activated by the downstream metabolic enzyme, glycerate kinase, and stabilizes the putative allantoin transporter by direct binding.

Allantoin is a good source of ammonium for many organisms, and in Escherichia coli it is utilized under anaerobic conditions. We provide evidence that allantoinase (AllB) is allosterically activated by direct binding of the allantoin catabolic enzyme, glycerate 2-kinase (GlxK) in the presence of glyoxylate. Glyoxylate is known to be an effector of the AllR repressor which regulates the allantoin utilization operons in E. coli. AllB has low affinity for allantoin, but its activation by GlxK leads to increased affinity for its substrate. We also show that the predicted allantoin transporter YbbW (re-named AllW) has allantoin specificity and the protein-protein interaction with AllB. Our results show that the AllB-dependent allantoin degradative pathway is subject to previously unrecognized regulatory mechanisms involving direct protein-protein interactions.

Urate as a physiological substrate for myeloperoxidase: implications for hyperuricemia and inflammation.

Urate and myeloperoxidase (MPO) are associated with adverse outcomes in cardiovascular disease. In this study, we assessed whether urate is a likely physiological substrate for MPO and if the products of their interaction have the potential to exacerbate inflammation. Urate was readily oxidized by MPO and hydrogen peroxide to 5-hydroxyisourate, which decayed to predominantly allantoin. The redox intermediates of MPO were reduced by urate with rate constants of 4.6 × 10(5) M(-1) s(-1) for compound I and 1.7 × 10(4) M(-1) s(-1) for compound II. Urate competed with chloride for oxidation by MPO and at hyperuricemic levels is expected to be a substantive substrate for the enzyme. Oxidation of urate promoted super-stoichiometric consumption of glutathione, which indicates that it is converted to a free radical intermediate. In combination with superoxide and hydrogen peroxide, MPO oxidized urate to a reactive hydroperoxide. This would form by addition of superoxide to the urate radical. Urate also enhanced MPO-dependent consumption of nitric oxide. In human plasma, stimulated neutrophils produced allantoin in a reaction dependent on the NADPH oxidase, MPO and superoxide. We propose that urate is a physiological substrate for MPO that is oxidized to the urate radical. The reactions of this radical with superoxide and nitric oxide provide a plausible link between urate and MPO in cardiovascular disease.

Ureide catabolism in Arabidopsis thaliana and Escherichia coli.

The availability of whole genome sequences boosts the identification of biochemical pathways conserved across species using tools of comparative genomics. A cross-organism protein association analysis allowed us to identify two enzymes, ureidoglycine aminohydrolase and ureidoglycolate amidohydrolase, that catalyze the final reactions of purine degradation in the model plant Arabidopsis thaliana. A similar pathway was found in Escherichia coli, while an alternative metabolic route via ureidoglycine transaminase can be predicted for other organisms.

Characterization of the decomposition of compounds derived from imidazolidinyl urea in cosmetics and patch test materials.

BACKGROUND: Imidazolidinyl urea releases formaldehyde through decomposition. However, there have been few reports on the chemistry of imidazolidinyl urea in cosmetics. OBJECTIVES: The aim of this study was to characterize imidazolidinyl urea-derived compounds in cosmetics and to determine which compounds are responsible for the cross-reactivity with diazolidinyl urea. METHODS: We analysed imidazolidinyl urea dissolved in aqueous solutions, imidazolidinyl urea patch test materials and imidazolidinyl urea-preserved cosmetics by high-performance liquid chromatography/photodiode array detection and liquid chromatography/mass spectrometry. The results were compared with those obtained with a diazolidinyl urea aqueous solution. RESULTS: In the analysed cosmetic samples and patch test materials, imidazolidinyl urea was primarily composed of allantoin, (4-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea (HU), (3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea (3,4-BHU), and (3-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea. CONCLUSIONS: Two of the imidazolidinyl urea-derived major decomposition compounds - HU and 3,4-BHU - are common in the diazolidinyl urea-decomposed compound present in cosmetics. These compounds are possible causative agents of the cross-reactivity between diazolidinyl urea and imidazolidinyl urea.

Structural and mechanistic studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase.

The stereospecific oxidative degradation of uric acid to (S)-allantoin was recently shown to proceed via three enzymatic steps. The final conversion is a decarboxylation of the unstable intermediate 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) and is catalyzed by OHCU decarboxylase. Here we present the structures of Klebsiella pneumoniae OHCU decarboxylase in unliganded form and with bound allantoin. These structures provide evidence that ligand binding organizes the active site residues for catalysis. Modeling of the substrate and intermediates provides additional support for this hypothesis. In addition we characterize the steady state kinetics of this enzyme and report the first OHCU decarboxylase inhibitor, allopurinol, a structural isomer of hypoxanthine. This molecule is a competitive inhibitor of K. pneumoniae OHCU decarboxylase with a K(i) of 30 ± 2 µM. Circular dichroism measurements confirm structural observations that this inhibitor disrupts the necessary organization of the active site. Our structural and biochemical studies also provide further insights into the mechanism of catalysis of OHCU decarboxylation.

Discovery of an alternate metabolic pathway for urea synthesis in adult Aedes aegypti mosquitoes.

We demonstrate the presence of an alternate metabolic pathway for urea synthesis in Aedes aegypti mosquitoes that converts uric acid to urea via an amphibian-like uricolytic pathway. For these studies, female mosquitoes were fed a sucrose solution containing (15)NH4Cl, [5-(15)N]-glutamine, [(15)N]-proline, allantoin, or allantoic acid. At 24 h after feeding, the feces were collected and analyzed in a mass spectrometer. Specific enzyme inhibitors confirmed that mosquitoes incorporate (15)N from (15)NH4Cl into [5-(15)N]-glutamine and use the (15)N of the amide group of glutamine to produce labeled uric acid. More importantly, we found that [(15)N2]-uric acid can be metabolized to [(15)N]-urea and be excreted as nitrogenous waste through an uricolytic pathway. Ae. aegypti express all three genes in this pathway, namely, urate oxidase, allantoinase, and allantoicase. The functional relevance of these genes in mosquitoes was shown by feeding allantoin or allantoic acid, which significantly increased unlabeled urea levels in the feces. Moreover, knockdown of urate oxidase expression by RNA interference demonstrated that this pathway is active in females fed blood or (15)NH4Cl based on a significant increase in uric acid levels in whole-body extracts and a reduction in [(15)N]-urea excretion, respectively. These unexpected findings could lead to the development of metabolism-based strategies for mosquito control.

Formulation, optimization and characterization of allantoin-loaded chitosan nanoparticles to alleviate ethanol-induced gastric ulcer: in-vitro and in-vivo studies.

Allantoin (ALL) is a phytochemical possessing an impressive array of biological activities. Nonetheless, developing a nanostructured delivery system targeted to augment the gastric antiulcerogenic activity of ALL has not been so far investigated. Consequently, in this survey, ALL-loaded chitosan/sodium tripolyphosphate nanoparticles (ALL-loaded CS/STPP NPs) were prepared by ionotropic gelation technique and thoroughly characterized. A full 24 factorial design was adopted using four independently controlled parameters (ICPs). Comprehensive characterization, in vitro evaluations as well as antiulcerogenic activity study against ethanol-induced gastric ulcer in rats of the optimized NPs formula were conducted. The optimized NPs formula, (CS (1.5% w/v), STPP (0.3% w/v), CS:STPP volume ratio (5:1), ALL amount (13 mg)), was the most convenient one with drug content of 6.26 mg, drug entrapment efficiency % of 48.12%, particle size of 508.3 nm, polydispersity index 0.29 and ζ-potential of + 35.70 mV. It displayed a sustained in vitro release profile and mucoadhesive strength of 45.55%. ALL-loaded CS/STPP NPs (F-9) provoked remarkable antiulcerogenic activity against ethanol-induced gastric ulceration in rats, which was accentuated by histopathological, immunohistochemical (IHC) and biochemical studies. In conclusion, the prepared ALL-loaded CS/STPP NPs could be presented to the phytomedicine field as an auspicious oral delivery system for gastric ulceration management.

[Chemical contituents in leaves of Ehretia thyrsiflora].

OBJECTIVE: To investigate the chemical constituents of Ehretia thyrsiflora. METHOD: Compounds were isolated with silica gel, Sephadex LH-20 and RP-C18 colum chromatography. Their structures were elucidated by means of physico-chemical properties and spectral analysis. RESULT: Six compounds were isolated and identified as beta-sitosterol (1), ethyl caffeate (2), 2-methoxyl benzoic acid octyl ester (3), tetradecenoic acid, 2,3-dihydroxypropyl ester (4), daucoster (5), allantoin (6). CONCLUSION: Compounds 1-5 were obtained from this species for the first time. Compounds 2-5 were obtained from the genus Ehretia for the first time.

Natural Film Based on Pectin and Allantoin for Wound Healing: Obtaining, Characterization, and Rat Model.

INTRODUCTION: In our days, several approaches reported the use of natural compounds in medical applications. Among them, pectin and allantoin are nontoxic, biocompatible, and biodegradable; however, its use for possible wound healing therapeutics is still limited. Pectin and allantoin have been applied in pharmaceutical industry and beauty cosmetic and could be also applied as scaffolds for tissue regeneration, wound healing, and so on. The aim of this study was to combine by the first time two natural ingredients to develop a new biomaterial to treat skin injuries in a rat model. METHODS: For the hydrogel development, new synthesis parameters were established for the obtaining of the film such as temperature, mixing velocity and time, and drying temperatures as well. To enrich the film, the allantoin concentrations were set at 90 wt% and 100 wt% of pectin used. By in vivo assay, films were tested in wound healing in female Wistar rats, 190 ± 10 g in weight and 2 months aged. RESULTS: The obtained films comprise 2 well-differentiated layers, one layer rich in allantoin, which will be the regenerative layer, and one rich in pectin, which will work as an antimicrobial and protective layer to the wound. These were characterized by swelling kinetics, Fourier transform of the infrared spectrum of absorption (FTIR) spectroscopy, and contact angle. The morphology and topography were determined by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). In vivo assay showed remarkable reduce in a time period in a wound healing process when the film was used. The results show that the use of PA (Pectin-Allantoin) hydrogel reduces the total healing time by 25% approximately. CONCLUSIONS: Pectin-Allantoin (PA) film has potential use in medical applications as wound healing material promoting healthy tissue renewal.

Fabrication of bioinspired chitosan/gelatin/allantoin biocomposite film for wound dressing application.

A biocomposite film composed of biopolymers chitosan (CS), gelatin (GE) and allantoin (AT) was fabricated by solution casting technique. The functional group interaction of the biocomposite films was inspected through the Attenuated total reflectance Fourier transform spectrometer (ATR-FTIR). The morphological changes and crystallinity of biocomposite films with varied ratios of chitosan/gelatin (CS/GE) and allantoin were examined under Scanning electron microscope (SEM) and X-ray diffractometer (XRD). The water-absorbing capacity was found enhanced by an increase in the chitosan ratio. The biocomposite films exhibit good antioxidant, anti-inflammatory properties. The biocomposite films also display enhanced stability with steady degradation under the PBS medium. The biocomposite films reveal improved antibacterial activity against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus). Blood compatibility studies explore the non-hemolytic nature. The in vitro cytotoxicity by MTT assay shows excellent biocompatibility. The fibroblast adhesion on the biocomposite film displays enhanced proliferation and viability. These significant biological properties of biocomposite film make it an appropriate candidate for wound dressing application.

Absolute configurations of spiroiminodihydantoin and allantoin stereoisomers: comparison of computed and measured electronic circular dichroism spectra.

The assignment of absolute configurations is of critical importance for understanding the biochemical processing of DNA lesions. The diastereomeric spiroiminodihydantoin (Sp) lesions are oxidation products of guanine and 8-oxo-7,8-dihydroguanine (8-oxoG), and the absolute configurations of the two diastereomers, Sp1 and Sp2, have been evaluated by experimental and computational optical rotatory dispersion (ORD) methods. In order to support our previous assignments by the ORD method, we calculated the electronic circular dichroism spectra (ECD) of the Sp stereoisomers. Comparison of the experimentally measured and computed ECD spectra indicates that Sp1 has (-)-S absolute configuration, while Sp2 has (+)-R absolute configuration. Thus, the S and R assignments, based on the ECD spectra of Sp1 and Sp2, are consistent with our previous assignments of absolute configurations. To further test the validity of this approach, we performed a proof-of-principle computation of the ECD and ORD of the R and S enantiomers of allantoin (similar in chemical composition to Sp) of known absolute configurations. The calculations provide the correct assignment of the absolute configurations of the allantoin enantiomers, indicating that the computational TDDFT approach is robust for identifying the absolute configurations of allantoins and probably the Sp stereoisomers, as has been shown previously for other organic molecules.