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Background: Dioscorea opposita Thunb. cv. Tiegun maturity (DM) is an important factor influencing its quality. However, there are few studies on the impact of harvest time on its maturation. In the present study, a NMR-based metabolomics approach was applied to investigate the dynamic metabolic changes of D. opposita Thunb. cv. Tiegun at six different harvest stages: stage 1 (S1), stage 2 (S2), Stage 3 (S3), stage 4 (S4), stage 5 (S5) and stage 6 (S6)., Results: Principal component analysis showed distinct segregation of samples obtained from S1, S2 and S3 compared to those derived from S4, S5 and S6. Interestingly, these samples from the two periods were obtained before and after frost, indicating that frost descent might be important for DM. Eight differential metabolites responsible for good separation of different groups were identified by the principal component analysis loading plot and partial least squares-discriminant analysis. In addition, quantitative analysis of these metabolites using liquid chromatography-tandem mass spectrometry determined the effects of harvest time on these metabolite contents, two of which, sucrose and allantoin, were considered as potential biomarkers to determine DM., Conclusion: The present study demonstrated that NMR-based metabolomics approach could serve as a powerful tool to identify differential metabolites during harvesting processes, also offering a fresh insight into understanding the DM and the potential mechanism of quality formation. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Allantoin is an abundant component of yams and has been known as a skin protectant due to its pharmacological activities. In previous methods for allantoin determination using high-performance liquid chromatography (HPLC), the separation was unsatisfactory. We herein developed a 1 H quantitative nuclear magnetic resonance (qNMR) method for quantification of allantoin in the flesh and peel of yams. The method was carried out based on the relative ratio of signals integration of allantoin to a certain amount of the internal standard dimethyl sulfone (DMSO 2 ) and validated in terms of specificity, linearity (range 62.5-2000 μg/ml), sensitivity (limit of detection (LOD) and quantification (LOQ) 4.63 and 14.03 μg/ml, respectively), precision (RSD% 0.02-0.26), and recovery (86.35-92.11%). The method was then applied for the evaluation of allantoin in flesh and peel extracts of four different yams cultivated in Korea.

The accumulation of allantoin and trace metals (TMs) in nine moss species was examined after the exposure to stress conditions. Both the environmental anthropopressure effect and laboratory-simulated stress conditions were monitored. Moss samples were collected from different locations, i.e. a non-TM contaminated area, an urban area, and a metalliferous area. The effect of Cd, Pb, Hg, Ni, Zn, salinity, and an acidic environment on the allantoin content was tested. Principal component analysis was performed to reveal the relationship between samples of different origin. Large differences in the metal and allantoin accumulation capability of mosses were noted between samples harvested from the different locations. Seven species were considered as potential metal accumulators, as they exhibited tolerance to elevated levels of heavy metals. The observed TM effect on the allantoin accumulation indicated TM pollution as an important environmental factor that can significantly influence the content of this compound in mosses. Further studies on the contribution of various environmental factors and individual characteristics of plant species are highly expected to recognize the trend in the accumulation of specialized metabolites and TMs in response to hazardous growth conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Uric acid and its oxidation product allantoin are excellent biomarkers of oxidative stress in humans. Currently, there are high requirements not only for tests monitoring oxidative stress but also for screening laboratory tests in general. The highest demand is imposed on the simplest sampling, easy transport of the sample, and the shortest possible analysis time. The possible solution how to fulfil the requirements is sampling by dried blood spot technique with subsequent HPLC-MS/MS analysis. A fast, sensitive, and reliable HPLC-MS/MS method for the simultaneous determination of uric acid and allantoin from dried blood spots using stable isotopically labelled analogs as internal standards was developed. The separation took place in the reversed phase within 3 min, with protein precipitation and extraction in a one-step procedure. The analytical parameters of the method were satisfactory with an excellent linear range. The presented method was used to determine allantoin and uric acid levels in dried blood spot samples from 100 healthy volunteer donors. The median uric acid concentration in the cohort was 239.3 µmol/L and the median allantoin concentration was 5.6 µmol/L. The presented analytical protocol and method are suitable for screening and monitoring allantoin and uric acid levels as biomarkers of oxidative stress in clinical practice., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Using the skin tissue engineering approach is a way to help the body to recover its lost skin in cases that the spontaneous healing process is either impossible or inadequate, such as severe wounds or burns. In the present study, chitosan/gelatin-based scaffolds containing 0.25, 0.5, 0.75, and 1% allantoin were created to improve the wounds' healing process. EDC and NHS were used to cross-link the samples, which were further freeze-dried. Different in-vitro methods were utilized to characterize the specimens, including SEM imaging, PBS absorption and degradation tests, mechanical experiments, allantoin release profile assessment, antibacterial assay, and cell viability and adhesion tests. The results indicated that the scaffolds' average pore sizes were approximately in the range of 390-440 µm, and their PBS uptake amounts were about 1000% to 1250% after being soaked in PBS for 24 h. Around 70% of the specimens were degraded in 6 days, but they were not fully degraded after 21 days. Besides, the samples showed antibacterial activity against S. aureus and E. coli bacteria. In general, the MTT cell viability test indicated that the cells' density increased slightly or remained the same during the experiment. SEM images of cells seeded on the scaffolds indicated appropriate properties of the scaffolds for cell adhesion., (© 2021. The Author(s).)

Dioscorea polystachya, named Chinese yam, is widely cultivated as a functional food and natural medicine in China. There is currently little information about the chemical characteristics of Dioscorea polystachya in different organs (tuber cortex and tuber flesh) and at various ages. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was used to profile chemical compounds in Dioscorea polystachya. As a result, thirty-eight compounds were detected in yam tuber cortex and tuber flesh. More compounds were detected in yam tuber cortex than in tuber flesh. Compounds such as dehydroepiandrosterone, allantoin and flavonoids were selected as biomarker candidates. Dehydroepiandrosterone was found more abundant in tuber flesh, while allantoin and flavonoids showed higher levels in tuber cortex. Furthermore, the levels of dioscin, malvalic acid and sucrose differed significantly among age groups and were highest in the tubers at 2 years. While the levels of allantoin, adenosine and glutamine increased with the growing years and were highest at 4 years. Thus, 2-year old Dioscorea polystachya tubers could be harvested to prepare dioscin, malvalic acid and sucrose supplements. The 4-year-old Dioscorea polystachya tubers would be the best choice for obtaining a large amount of allantoin and adenosine in industrial production., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

In plants, long-distance transport of chemicals from source to sink takes place through the transfer of sap inside complex trafficking systems. Access to this information provides insight into the physiological responses that result from the interactions between the organism and its environment. In vivo analysis offers minimal perturbation to the physiology of the organism, thus providing information that represents the native physiological state more accurately. Here we describe capillary microsampling with electrospray ionization mass spectrometry (ESI-MS) for the in vivo analysis of xylem sap directly from plants. Initially, fast MS profiling was performed by ESI from the whole sap exuding from wounds of living plants in their native environment. This sap, however, originated from the xylem and phloem and included the cytosol of damaged cells. Combining capillary microsampling with ESI-MS enabled targeted sampling of the xylem sap and single parenchymal cells in the pith, thereby differentiating their chemical compositions. With this method we analyzed soybean plants infected by nitrogen-fixing bacteria and uninfected plants to investigate the effects of symbiosis on chemical transport through the sap. Infected plants exhibited higher abundances for certain nitrogen-containing metabolites in their sap, namely allantoin, allantoic acid, hydroxymethylglutamate, and methylene glutamate, compared to uninfected plants. Using capillary microsampling, we localized these compounds to the xylem, which indicated their transport from the roots to the upper parts of the plant. Differences between metabolite levels in sap from the infected and uninfected plants indicated that the transport of nitrogen-containing and other metabolites is regulated depending on the source of nitrogen supply.

A TLC-densitometric method for determination of allantoin in Symphytum officinale root was developed. Densitometric quantification of allantoin was carried out on TLC Si60 plates with butanol-50 % methanol/formic acid, 66.5:33.2:0.3 (V/V/V) as developing solvent, at a wavelength of 190 nm. The method was preliminarily validated in terms of specificity, linearity, precision, limit of detection, limit of quantification, recovery and robustness. The results of TLC quantification were compared with HPLC analysis carried out on a HILIC Luna NH2 100A column, with mobile phase consisting of acetonitrile/water 80:20 (V/V) and UV detection at 190 and 210 nm. Allantoin content was determined in two herbal products and it varied from 0.94 to 2.09 %, depending on the producer, and was in agreement with literature reports.

The use of lactic bacteria in the development of functional foods has increased in recent years. In addition to their probiotic characteristics, they can ferment a variety of substrates, such as cereals, roots, and tubers. Phytase producer lactic acid bacteria strains and their behavior during the fermentation process of yam-based food were studied. Leuconostoc lactis CCMA 0415, Lactobacillus plantarum CCMA 0744, and Lactobacillus fermentum CCMA 0745 were selected due to phytase production, pH reduction, and growth during 24 h of fermentation. Oxalate activity was not detected in all assays, suggesting its concentration was reduced due to the bleaching process. Among the selected strains, L. lactis CCMA 0415 appeared to be a promising strain in yam-based fermentations because it maintained a cell viability above 8 log CFU/mL and did not reduce diosgenin concentrations (around 8.0 μg/mL) after fermentation for 24 h, thereby, generating a potentially functional yam food. Furthermore, this strain promoted the decrease of pH value from 6.1 to 3.8 and produced 8.1 g/L lactic acid, at 6 h of fermentation. The L. lactis CCMA 0415 was reported as a starter culture in fermented products based on cereals, roots, and tubers.

Allantoin, an important intermediate of ureide metabolism, has been the subject of investigation recently due to its dual function in nitrogen recycling and abiotic stress response in plants. Allantoin appears to be the dominant ureide accumulating in response to different abiotic stresses, and mutants containing elevated allantoin concentrations exhibit a stress-tolerant phenotype due to limited reactive oxygen species (ROS) generation. Here we describe the involvement of allantoin in stress response and attempt to explain the regulatory mechanism(s) underlying allantoin function in plants. Growth of wild type Col-0 seedlings in the presence of exogenous allantoin improved root elongation in response to Cd treatment. Allantoin treatment of Col-0 seeds increases superoxide dismutase activity causing an enhanced seed germination and seedling growth following Cd exposure. Additionally, allantoinase-overexpressed (ALNox) lines, with lower levels of allantoin, exhibited more susceptibility to Cd treatment than Col-0 Arabidopsis, implying that there is a positive correlation between allantoin concentration and Cd resistance in plants. Growing ABA-insensitive (abi) mutants on allantoin-containing media and comparison between abi mutants and their wild-type backgrounds demonstrated that the potential regulatory function of allantoin does not require ABA at germination but may be ABA-dependent at later stages of seedling growth, suggesting a potential crosstalk between allantoin-mediated stress response and ABA signalling pathway in plants., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Snail mucus is a mixture of active substances commonly thought to have healthy properties for the treatment of skin disorders. Although snail mucus is an ingredient of several cosmetic and para-pharmaceutic products, a comprehensive characterization of chemical composition and biological effects is still missing. Crude purified extracts from Helix aspersa muller mucus (HelixComplex) were prepared and, after chemical characterization, tested on in vitro experimental models. Differently from what expected, HelixComplex was characterized by the presence of small amounts of glycolic acid and allantoin. By using different in vitro assays on fibroblast cultures, we found that HelixComplex lacked of cytotoxicity, protected cells from apoptosis (p < 0.05) and, importantly, was able to significantly induce cell proliferation and migration through direct and indirect mechanisms. These effects were associated to morphological changes, cytoskeleton re-organization and release of cytokines. In conclusion, our findings suggest that snail mucus biological effects are attributable to cell proliferation and migration, and pave the way for further investigating snail mucus potential as therapeutic agent.

Abiotic stress, including metal excess, can modify plant metabolism. Here we investigated the influence of long-term strontium exposure (12 weeks, 0.5⁻4.0 mM Sr) on the content of phytoestrogens and allantoin as well as the mineral composition in soybean. Seven phytoestrogens were identified in the soybean: daidzin, glycitin, genistin, malonyldaidzin, malonylgenistin, daidzein, and coumestrol. The results showed that both malonyldaidzin and malonylgenistin were dominant phytoestrogens; however, the roots contained a relatively high amount of daidzein. It was found that strontium reduced the phytoestrogen content and decreased the antioxidant capacity. Strontium evoked depletion of the sum of all phytoestrogens by 40⁻70% in the leaves, 25⁻50% in the stems and in the seeds, depending on the strontium concentration. In the roots, 0.5 and 4.0 mM of strontium decreased the total phytoestrogen content by 25 and 55%, respectively, while 2.0 mM of strontium did not exert an effect on their accumulation. On the other hand, strontium ions induced allantoin accumulation mainly in the roots. Strontium was preferentially accumulated in the leaves, with a slight impact on macro- and micro-nutrients. Our research showed strontium-secondary metabolites interaction in the soybean, which can be useful for obtaining a natural pharmaceutical product containing both strontium and phytoestrogens for remediation of postmenopausal osteoporosis.

Chinese yam (CY), used as both a traditional Chinese medicine and a nutritious food, is an excellent candidate for treating septic cardiomyopathy (SCM). Adenosine, arbutin and allantoin are the major active components in the aqueous extract of CY. The aim of the present study was to interpret the roles of CY, adenosine, arbutin and allantoin in SCM treatment. Firstly, significant physiological indexes were examined to assess the model and treatment effects of CY, adenosine, arbutin and allantoin. Then, a metabolomic approach was utilized to reveal the metabolic disorders in SCM concerning the intervention of CY/adenosine/arbutin/allantoin. The integrated results demonstrated that adenosine, arbutin and allantoin are responsible for the efficacy of CY on SCM treatment by regulating amino acid, arachidonic acid, sphingolipid, glycerophospholipid and glycol metabolism. Moreover, adenosine and/or arbutin could be used as a substitute for CY in treating SCM, and allantoin efficacy was slightly weaker. This integrated metabolomic approach performed excellently in understanding the herbal function and the roles of its components.

The root of Symphytum officinale L. is commonly used in folk medicine to promote the wound healing, reduce the inflammation and in the treatment of broken bones. The objective of our investigation was to analyse the extract from S. officinale in term of its antioxidant activity and the effect on cell viability and proliferation of human skin fibroblast (HSF). Moreover, the quantification of main phenolics and allantoin was conducted using HPLC-DAD method. Five compounds were found: rosmarinic, p-hydroxybenzoic, caffeic, chlorogenic and p-coumaric acid. DPPH, FRAP and TPC assay showed the high antioxidant activity of the extract. MTT test proved the stimulatory effect on cell metabolism and viability of HSF cells. Moreover, no changes in cytoskeleton structure and cells shape were observed. The obtained results indicate that non-toxic extract from S. officinale root has strong antioxidant potential and a beneficial effect on human skin fibroblasts.

This paper is a personal review of the role developments in separation science over the last four decades have played in the diagnosis and understanding of purine and pyridine metabolism particularly in man. In 1967 the separation of nucleotides was used to demonstrate a new chromatography technique. This technique became known as HPLC and which continues to dominate the analysis of purines etc. The resolution and quantitation offered by even the earliest HPLC systems completely changed our understanding of matters such as nucleotide instability in cells and tissues, diagnosis of in born errors, etc. Capillary Electrophoresis also enabled high resolution as well as the quantitation of usual analytes such allantoin. Now LC-MS dominates the diagnostic field. This paper is based on the Anne Simmonds Lecture given by the author at PP17 in Gdansk in 2017.

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.

Plants apply various molecular, physiological and morphological strategies in response to undesirable environmental conditions. One of the possible responses which may contribute to surviving stressful conditions is the accumulation of ureides. Ureides are recognized as important nitrogen-rich compounds involved in recycling nitrogen in plants to support growth and reproduction. Amongst them, allantoin not only serves as a transportable nitrogen-rich compound, but has also been suggested to protect plants from abiotic stresses via minimizing oxidative damage. This work focuses on the effect of cadmium (Cd) on ureide metabolism in Arabidopsis, in order to clarify the potential role of allantoin in plant tolerance to heavy metals. In response to Cd treatment, allantoin levels increase in Arabidopsis thaliana, ecotype Col-0, due to reduced allantoinase (ALN) gene expression and enzyme activity. This coincides with increases in uricase (UO) transcripts. UO and ALN encode the enzymes for the production and degradation of allantoin, respectively. ALN-negative aln-3 Arabidopsis mutants with elevated allantoin levels demonstrate resistance to soil-applied CdCl 2 , up to 1,500 μM. Although aln-3 mutants take up and store more Cd within their leaf tissue, they contain less damaging superoxide radicals. The protective mechanism of aln-3 mutants appears to involve enhancing the activity of antioxidant enzymes such as superoxide dismutase and ascorbate peroxidase., (© The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The aims of this study are to investigate the antioxidant and antitumor activities of the water and ethanol extracts isolated from Chinese yam (Dioscorea opposite Thunb.) flesh (CYF) and peel (CYP) and the effective compounds. It was found that all peel portions have a better effect on reactive oxygen (ROS) scavenging assay than meat portions, especially for the water extract of Chinese yam peel (CYP-W). Its IC50 values for hydroxyl radical (OH•) scavenging assay (744.25 ± 3.46 μg/mL) and for 1,1-diphenyl-2-picrylhydrazyl scavenging assay (374.85 ± 6.78 μg/mL) were both lower than that of yam flesh (CYF-W). Furthermore, the antitumor property of yam peel was more effective than that of yam flesh (CYF-W) on mouse models, with tumor inhibition rates were 47.92% and 27.41% for Ehrlich Ascites Tumor (EAC) model and 40.44% and 24.22% for H22 hepatocarcinoma tumor (H22) model. Meanwhile, extracts of peel showed higher allantoin, total flavonoids, and total phenolics contents than extracts of flesh. In conclusion, this study demonstrated that CYP-W exerted better antitumor activity than flesh extracts and the scavenging ROS effects were also significantly higher in the CYP-W in vitro. Moreover, the data indicated that allantoin may play an important role on antioxidative and antitumor capacity in yam peel., (© 2016 Institute of Food Technologists®)

To breed a new yam cultivar of Dioscorea alata, the different and excellent germplasm resources were investigated within artificially cultivated population and some superior individuals, with a higher yield and medicinal properties, were selected. Considering results of the yield and medicinal properties during 2006-2013 cropping season, strains and lines were established and selected. As a result, the yield of the new developed cultivar (Wenshanyao No. 1, WSY01-1) reached 2217. 0 kg per 667 m2 (fresh weight) and 348.3 kg per 667 m2 (dry weight), and increased 23.8% and 23.9% comparing with control cultivars (landraces). Comparing with control cultivars, the level of polysaccharide, allantoin, and dioscin increased 36.9%, 48.3%, 20.9%, and reached 12.2%, 1.30%, 579.7 µg · g(-1), respectively. This result showed that the systematic selection method can significantly improve yield and medicinal properties of D. alata, and the developed " Wenshanyao No. 1" exhibits wide spreading prospects.

A new methodology for simultaneous quantitative analysis of allantoin and glycolic acid in snail mucus and cosmetic creams was developed. HPLC separation was achieved a Synergi-Hydro RP column within 7min using isocratic elution with potassium phosphate (pH 2.7; 10mM) at a flow rate of 0.7mL/min at 30°C. Sample pretreatment was performed by dilution of mucus or cosmetic cream in the elution buffer, heating at 60°C for 20min, adjusting the pH to 2.9 and purification with hexane extraction. Linearity was determined with spiked samples and the LLOQ values of 0.0125 and 0.2500mg/mL were determined for allantoin and glycolic acid, respectively. Accuracy and intra- and inter-day repeatability were studied at three levels of concentrations (0.04, 0.08 and 0.16mg/mL for allantoin and 0.1, 1.5 and 4.0mg/mL for glycolic acid) using spiked mucus and cream base samples; mean values of recovery were in the range of 96.81-102.42% in all matrices tested, whereas the respective RSDs (%Relative Standard Deviation) were less than 3.04% in all cases. Spiked mucus and cream samples were stable (RSD<4.16 and relative error<4.34%) at room temperature and at 4°C for 1 week and at -18°C for 6 months; samples were also stable after three freeze-thaw cycles. The method was applied to the analysis of different lots of snail mucus, and of three commercial creams containing snail mucus., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A method for determintion of allantion in Psammosilene tunicoides was established by HPLC. Using alcohol as the extraction solvent, the subsequent filtrate of P. tunicoides was analysed by HPLC. Allantoin was successfully detected and separated by ZORBAX NH2 column (4.6 mm x 150 mm,5 microm) at wavelength of 220 nm and column temperature of 40 degrees C, with acetonitrile-water (93: 7) as mobile phase at a flow rate of 1.0 mL x min(-1). The results showed that it had a good linear relationship between the concent ration of allantion and chromatographic peak area. The linear correlation coefficient of allantion was 0.999 5 in 0.010 4-0.166 g x L(-1). The relative standard deviation of six parallel injections was less than 2.1%. The average recoveries were ranged from 95.47% to 100.9%. This method was sensitive and accurate for the determination of allantion in P. tunicoides.

Ethnopharmacological Relevance: Pyrostegia venusta is a native Brazilian plant which has a variety of uses in traditional folk medicine including the treatment of vitiligo. However, its effectiveness on melanogenesis is not yet elucidated., Aim of the Study: This study aimed to investigate the melanogenic activity of hydroalcoholic extracts from the leaves and flowers of P. venusta on murine B16F10 melanoma cells., Materials and Methods: Different concentrations of the hydroalcoholic extracts of flowers and leaves of P. venusta were evaluated in trials of spontaneous melanin content (4 days), and cell viability by the MTT assay in murine B16F10 cells, and in the mushroom tyrosinase activity in vitro., Results: Both extracts, leaves (0.1; 0.3; 1 and 3 μg/mL) and flowers (0.03 and 0.1 μg/mL) increased the melanin content in a concentration dependent manner after 4 days of incubation on melanoma cells. Leaves extract promoted enhancement of melanogenesis with maximum effect of 33.3±3% (3 μg/mL), and the flower extract increased in 23.4±3% (0.1 μg/mL). The cell viability test using MTT showed that in the same tested concentrations of both extracts no cell death was detected. Actually, either extract was not able to cause any change in the tyrosinase activity. HPLC analysis of P. venusta extracts found 0.09% and 1.08% of allantoin on leaves and flowers extracts, respectively., Conclusions: The leaves and flowers extracts of P. venusta stimulates B16F10 melanogenesis at very low concentrations. These findings support the folk medicinal use of P. venusta on the treatment of hypopigmentation diseases, such as vitiligo., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

The aim of this work was to develop and validate an ultraviolet derivative spectrophotometric (UVDS) method for the quantitative determination of allantoin (ALL) in liposomes, gels and creams. Liposomes were prepared by methods of thin film hydration and mechanical agitation. Solutions of ALL in 0.1 mol/L NaOH with ethanol:water (70:30, v/v) were prepared in order to destroy liposome vesicles. Spectral interference from components of liposomes, cream, gel and ALL degradation products was eliminated using the second-order derivative of the zero-order spectrum. Characterization of ALL in 0.1 mol/L NaOH was carried out by direct infusion mass spectrometry. Absorbances of ALL solutions were measured at 266.6 nm of the second-derivative spectrum and linearity was observed in the ALL concentration range of 50-300 μgmL(-1) (correlation coefficient (r)=0.9961). The mean recovery percentage was 100.68 ± 1.61, repeatability expressed as relative standard deviation (RSD) was 1.07 and 2.12%, and intermediate precision (RSD) was 2.16%. The proposed UVDS method was found to be linear, precise, accurate, robust and selective, providing rapid and specific determination of ALL in raw materials and in topical formulations., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: To optimize the best gradient drying technology of pieces of sulfur-free Chinese yam, and provide technique parameter for processing of pieces of sulfur-free Chinese yam., Methods: Determined the content of polysaccharide by UV and the content of allantoin by HPLC. The optimum gradient drying technology of pieces of sulfur-free Chinese yam was investigated by orthogonal experiment and single factor experiment and the contents of polysaccharide and allantoin were regarded as the investigated indexes., Results: The optimum processing technology of first gradient drying stage was A2B2, that was drying for 60 min at 115 degrees C; The optimum drying temperature of second drying stage was 65 degrees C., Conclusion: The optimum technology is stable and feasible for the processing of pieces of sulfur-free Chinese yam.

Allantoin is the major oxidation product of urate in humans and is a potential biomarker of oxidative stress. Several methods are used to measure allantoin in biological samples but they have inherent issues that can include lack of specificity and sensitivity, difficulty in sample preparation, or artefactual generation of allantoin. We have developed a method for measuring allantoin using hydrophilic liquid chromatography with stable isotope dilution tandem mass spectrometry (HILIC-MS/MS). It was validated for measuring allantoin in plasma, synovial fluid and urine from human subjects. The limit of quantification was determined to be 10 fmol and the assay displayed excellent linearity for the wide range of concentrations found in clinical samples. Relative standard deviations were <5% for between-day and <7% for within-day variation. Accuracy was between 100% and 104%. Concentrations of allantoin in plasma of healthy controls (2.0 μM; interquartile range 1.4-3.6 μM, n=35) was significantly lower (p<0.001) than that in plasma from patients with rheumatoid arthritis (3.7 μM; IQR 3.0-5.6 μM, n=43) and in synovial fluid of patients with gout (3.3 μM; IQR 2.8-5.8 μM, n=10). This newer HILIC-MS/MS method is a simple and highly sensitive assay for detection of allantoin. It can be used to assess the level of oxidative stress in human pathologies., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Despite increasing knowledge of allantoin as a phytochemical involved in rice, relatively little is known about its distribution and function in rice grains. In this study, allantoin was quantified in 15 Chinese rice grains, and its contents varied with grain fraction, cultivar, and genotype. Bran always had the highest allantoin level, followed by brown rice and milled rice. Hull contained the lowest allantoin content. Allantoin in japonica bran ranged from 70 to 171 μg/g but rarely exceeded 100 μg/g in indica bran. There was a positive relationship between allantoin level in grains and seedling survival in seedbeds under low temperature or water deficit. Exogenous allantoin stimulated plant growth, increased soluble sugar and free proline contents, and decreased malondialdehyde content in rice seedlings. However, allantoin did not show any antioxidant activity through free radical-scavenging capacity, reducing power, linoleic acid peroxidation inhibition, and chelating activity. The results suggest that allantoin in rice grains may play some roles in providing plant stress protection but not serving as a beneficial health antioxidant.

A study was conducted to examine the physicochemical, microbial, and sensory properties of yogurt made by supplementing powdered yam Dioscorea opposita Thunb. (YPT) at different concentrations (0.2, 0.4, 0.6, and 0.8%, wt/vol) into milk, which was pasteurized and then fermented at 43°C for 6 h and stored for 16 d. The pH values of all samples decreased, whereas viscosity values and mean microbial counts increased during storage. The L* and a* color values (indicators of lightness and redness, respectively) of yogurt samples were not remarkably influenced by adding YPT, whereas the b* values (indicating yellowness) significantly increased with the addition of YPT at all concentrations at 0 d of storage, probably due to the original yellow color of yam powder. In functional component analyses, when the concentration of YPT increased, the amount of allantoin and diosgenin proportionally increased. The content of allantoin was 3.22 and diosgenin 4.69 μg/mL when 0.2% (wt/vol) YPT was supplemented and did not change quantitatively during the storage period (16 d). The sensory test revealed that the overall acceptability scores of YPT-supplemented yogurt samples (0.2 to 0.6%, wt/vol) were quite similar to those of the control throughout the storage period of 16 d. Based on the data obtained from the present study, it was concluded that the concentrations (0.2 to 0.6%, wt/vol) of YPT could be used to produce YPT-supplemented yogurt without significant adverse effects on physicochemical, microbial, and sensory properties, and enhance functional components from the supplementation., (Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

An ion-pair high-performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of chondroitin sulfate sodium (CSS), allantoin and pyridoxine hydrochloride (VB(6)) in a commercial eye drops dosage form. An Alltima C(18) column (250 mm x 4.6 mm i.d., 5 microm) was used for the separation at room temperature, with 25 mM ammonium dihydrogen phosphate (containing 0.01% heptanesulfonic acid sodium salt) and acetonitrile (95:5, v/v) as the mobile phase at the flow rate of 0.5 mL min(-1). The detection wavelength for CSS, allantoin and VB(6) was 195 nm, 215 nm and 291 nm, respectively. The method showed good linearity for CSS, allantoin and VB(6), with correlation coefficients greater than 0.9996, in the range of 203.96-815.84 mg L(-1), 371.16-1488.64 mg L(-1), and 23.32-93.28 mg L(-1), respectively. The instrumental and method precisions were adequate with all relative standard deviations lower than 2.0%. The accuracy of this method, measured by the recovery of three compounds from spiked placebo solutions, was from 99.01% to 101.92%. The three components, CSS, allantoin and VB(6) were well separated from other ingredients and degradation products. This method is fast, simple, and can be used for direct and simultaneous determination of CSS, allantoin and VB(6) in the pharmaceutical preparation.

Objective: To study the processing technics of prepared slice of Rhizoma Dioscoreae for its industrial production., Method: The effect factors, such as stiring temperature (60, 80, 100 degrees C), stiring time (10, 20, 30 min) and the proportion of pieces and wheat bran (100: 5, 100: 10, 100: 15) were evaluated by orthogonal method. The content of allantoin in Rhizoma Dioscoreae was determine by HPLC method., Result: The amount of wheat bran could affect the content of allation significantly, and stiring temperature and stiring time almost had no effect on content of allantoin. The processing technics was tested by industrial produce, according to 11 batches from 4 growing regions. The result showed that the quality of industrial product was stable., Conclusion: That the amount of wheat bran can affect the quality of Rhizoma Dioscoreae greatly. The determined technics is simple and suitable for prepared slice of Rhizoma Dioscoreae industrival manufacture.

A new HPLC method for simultaneous measurement of diazolidinyl urea (DU), urea, and allantoin by hydrophilic interaction chromatography using a column packed with triazol-bonded silica particles is described. The calibration curves of DU, urea, and allantoin were linear over the ranges 2.5-125.0, 30-1250, and 0.25-18.75mg/L, respectively. The recoveries of DU, urea, and allantoin from homemade cosmetic samples ranged from 92.84% to 101.69%, 98.19% to 103.22%, and 95.75% to 102.09%, respectively. The peak relative standard deviation (RSD) values for the recovery tests of 3 concentrations/5 replicates were 3.03% for all compounds. In day-to-day measurement of recovery tests from homemade lotions over 3 consecutive days, the RSDs were less than 2.5% in all cases. This method was well validated and would be helpful for quickly analyzing these compounds in cosmetic samples.

Allantoin is one of important nitrogenous compounds in manure. In this study, the simulation experiment of aerobic composting was adopted to explore concentration changes, degradation and relevant influencing factors of allantoin-N during six manure composting. The result showed that the allantoin-N concentration was markedly different among different manures. The various livestock and poultry excreted 1.92-11.14gkg(-1) allantoin-N which accounted for 9.98-32.27% of the total excreted nitrogen. The changing trend of the allantoin-N concentration firstly increased (for 0-14 days), then decreased (for 14-70 days) during different manure composting, and the allantoin-N concentration after composting was lower than the initial allantoin-N concentration in all manure composting. During allantoin degradation for 14-70 days of composting, the half-life of allantoin-N was 57.76 days in broiler manure, 46.21 days in layer-hen manure, 27.73 days in hog manure, 25.67 days in sow manure, 38.51 days in young pig manure and 15.75 days in dairy manure, and the sequence in the half-life was chicken manure>pig manure>dairy manure. Allantoin degradation conformed to first-order kinetics. Through the correlation analysis, hippuric acid, hydrolyzable nitrogen, amino acid-nitrogen, HUN fraction, NO(3)(-)-N and total hydrolyzable nitrogen could be closely related to allantoin-N transforming during composting. Humification could be the main influencing factor for reducing allantoin-N concentration during composting.

A high-performance liquid chromatography (HPLC) method for the qualitative and quantitative analysis of allantoin in silk and seed of Zea mays has been developed. Allantoin separation in crude extract was achieved using a C 18 column and phosphate buffer solution (pH 3.0) as a mobile phase at ambient temperature at a flow rate of 1.0 mL/min and detected at 210 nm. The results showed that the amount of allantoin in samples was between 14 and 271 mg/100 g of dry plant material. A comprehensive validation of the method including sensitivity, linearity, repeatability, and recovery was conducted. The calibration curve was linear over the range of 0.2-200 microg/mL with a correlation coefficient of r2>0.999. Limit of detection (LOD, S/N=3) and limit of quantification (LOQ) values of the allantoin were 0.05 and 0.2 microg/mL (1.0 and 4.0 ng) respectively. The relative standard deviation (RSD) value of the repeatability was reported within 1.2%. The average recovery of allantoin added to samples was 100.6% with RSD of 1.5%.

One hundred primiparous and multiparous Holstein cows were used in an experiment to evaluate the effect of supplementing diets with either a plant- or an animal-based source of rumen-undegradable protein (RUP), with or without AA supplementation, during the transition period and early lactation on milk production response. The experimental design was a randomized block design with approximately one-third of the cows being primiparous. Cows were assigned to 1 of 4 prepartum diets introduced 3 wk before the expected calving date and switched to the corresponding postpartum diet at calving. Diets 1 (AMI) and 2 (AMI+) included a vegetable RUP source (heat- and lignosulfonate-treated canola meal), with diet 2 containing supplemental Lys x HCl and Met hydroxy analog sources [D,L-2 hydroxy-4-(methylthio)-butanoic acid; Alimet feed supplement]. Diets 3 (PRO) and 4 (PRO+) consisted of a blend of animal RUP sources (blood meal, fish meal, feather meal, and porcine meat and bone meal), with diet 4 containing supplemental Lys x HCl and Met hydroxy analog sources [D,L-2 hydroxy-4-(methylthio)-butanoic acid; Alimet]. During the first 4 wk of lactation, dry matter intake was less when synthetic Lys x HCl and Alimet were supplemented, but this effect was no longer evident in wk 5 to 9 of the experiment. Interestingly, despite the initial decrease in dry matter intake in the cows fed AA-supplemented diets, there was no effect of treatment on milk production or the ratio of fat-corrected milk to dry matter intake throughout the 17 wk of the study. Undegradable protein source (vegetable vs. animal) did not affect dry matter intake, milk production, or 3.5% fat-corrected milk production for the first 17 wk of lactation. The results of this study indicate that heat- and lignosulfonate-treated canola meal can be used as a source of undegradable protein in place of high-quality rumen-undegradable animal protein sources without negative effects on milk production when diets are equivalent in rumen degradable protein, RUP, and metabolizable Met and Lys. Despite other reports citing clear benefits to feeding supplemental synthetic Lys or Met in diets fed to high-producing lactating dairy cows, we were unable to provide additional evidence to support these findings. Additionally, there was a trend for whole-blood Lys concentrations to be greater for diets supplemented with Lys x HCl.

A 2-yr study investigated effects of different levels of concentrate supplementation on milk production, composition, and lactation curves in pastured dairy goats. For both years, 44 Alpine goats (Capra hircus; 55 +/- 11 kg body weight) were randomly allocated to 4 groups. Animals were supplemented with 0.66 (treatments A and B), 0.33 (treatment C), or 0 kg of concentrate (treatment D) per kg of milk over 1.5 kg/d. Mixed vegetative forages were rotationally grazed by the goats (treatments B, C, and D), except that treatment A was confined and fed alfalfa hay. Individual milk production was recorded daily, and milk samples were collected once every 2 wk for the 7-mo period (March to September) and analyzed for fat, protein, lactose, urea-N, nonesterified fatty acids, and allantoin (second year only). Milk yield and composition varied among dietary treatments, with some measures affected by year. Average daily milk yield was lowest for treatment D. The increased level of concentrate supplementation in treatment A led to 22% greater milk yield compared with treatment D. Milk production increased by 1.7 and 0.9 kg for each additional kilogram of concentrate fed per day during the first and second years, respectively. Average peak yield, time of peak yield, and persistency were lower for treatment D than for other treatments. The percentage of milk fat was lower for treatment D than for other treatments. Concentration of milk protein was greater for treatments A and B during the first year, and was higher for treatment C than for other treatments during the second year. Average milk lactose concentration was higher for treatments B and C than for other treatments. However, milk urea-N concentration in treatment A was higher than other treatments. Milk allantoin, used to estimate microbial proteins synthesis, was 20 to 25% greater for treatment A than for other treatments. Averaged across year, plasma urea-N and nonesterified fatty acids concentration were lowest for treatment B. Average organic matter intake was similar among treatments during both years. Ratios of acetate and propionate concentrations for treatment A were lowest among treatments. In conclusion, milk production and composition were affected by the feeding treatment and year. Increased level of nutrition lead to an increase in daily milk yield, peak yield, time of peak yield, and persistency compared with treatment D. Alpine dairy goats grazing on fresh forages without concentrate supplementation can produce milk inexpensively, and response to concentrate supplementation is greater for low quality pasture.

A rapid, easy and reproducible capillary electrophoresis (CE) method for the simultaneous determination of allantoin, choline and arginine in Rhizoma Dioscoreae was developed first time. Under the optimum condition, the three analytes could be well separated within 5 min in a 70 cm (60 cm effective length) x 75 microm i.d. capillary. The relative standard deviations for both migration time and peak height were less than 3.20%. The linear response range was 5.0-150, 0.9-100 and 1.0-200 microg/ml for arginine, choline and allantoin, respectively. The detection limit of three components was 2.0, 0.4 and 0.5 microg/ml for arginine, choline and allantoin, respectively. Contents of arginine, choline and allantoin in the crude drug of Rhizoma Dioscoreae could be easily determined by the proposed method with satisfactory results.

A RP-HPLC method for quantification of allantoin in silk of fifteen maize hybrids (Zea mays L., Poaceae) was described. Following extraction of the plant material with an acetone-water (7:3, VN) mixture, filtration and dilution, the extracts were analyzed without previous chemical derivatization. Separation and quantification were achieved using an Alltech Econosil C18 column under isocratic conditions at 40 degrees C. The mobile phase flow (20% methanol--80% water with 5 mM sodium laurylsulfate added at pH 2.5, adjusted with 85% orthophosphoric acid; pH of water phase was finally adjusted at 6.0 by addition of triethylamine) was maintained at 1.0 mL/min. Column effluent was monitored at 235 nm. This simple procedure afforded efficient separation and quantification of allantoin in plant material, without interference of polyphenols or other plant constituents of medium to high polarity, or similar UV absorption. Our study revealed that the silk of all investigated maize hybrids could be considered relatively rich in allantoin, covering the concentration range between 215 and 289 mg per 100 g of dry plant material.

Solubility and bioavailability of poorly water-soluble drugs have been improved by the preparation as cyclodextrin inclusion complexes. The aim of this study is to obtain and characterize the inclusion compound allantoin-beta-cyclodextrin. Allantoin is a vegetable drug, poorly water-soluble (1:300), isolated from roots of Symphytum off. The solid inclusion complex was prepared by mixing with a adequate quantity of water and drying at 50 degrees C to the constant weight. It was used a different proportions between allantoin and beta-cyclodextrin (1:4, 3:7). The inclusion complex was characterized with RMN and IR spectrum and compared with results obtained from beta-cyclodextrin and allantoin alone. The experimental results were demonstrated the inclusion of allantoin in the lipophilic cavity of beta-cyclodextrin without physico-chemical changes.

Three experiments were conducted to determine the effect of diet change, milk sampling technique, and bovine somatotropin (bST) on allantoin output in milk and the use of allantoin as a practical, noninvasive method for estimating microbial protein flow in dairy cattle. In experiment 1, four lactating Holstein cows were used in a 2 x 2 Latin square design with two treatments (ratio of forage to concentrate) and two periods. In experiment 2, six Holstein cows were used in a completely randomized design, and milk was collected by 1) a strip sample collected immediately before milking, 2) a strip sample collected 3 min from start of milking, and 3) a composite sample taken with an autosampler. In experiment three, 10 cows were used in a randomized block design to determine the effect of bST on milk allantoin. Milk samples were taken daily for 21 d, 7 d before, and 14 d after bST administration. In experiment 1, allantoin output (mmol/d) was significantly greater for cows fed the higher ratio of concentrate to forage, and there was a significant change in the amount of allantoin in milk 12 h (first subsequent milking) after a diet change. There was no difference in milk yield or dry matter intake between treatments. In experiment 2, no difference was detected in milk allantoin concentration among the three sampling methods. In experiment 3, milk yield, allantoin concentration, and total allantoin output was significantly increased after bST administration even though dry matter intake (DMI) remained unchanged. During the first 14 d following bST administration, estimates of microbial protein production derived from milk allantoin may be inaccurate due to increased milk production without an increase in DMI.

Use of one-electron oxidants such as Na(2)IrCl(6) to oxidize 8-oxo-7,8-dihydro-2'-deoxyguanosine (OG) residues in oligodeoxynucleotides was previously shown to lead to predominant formation of a base lesion of mass M - 10 compared to starting material [Duarte et al. (1999) Nucleic Acids Res. 27, 596-502]. To thoroughly characterize the structure of this lesion, the oxidation of the nucleoside 9-N-(2',3',5'-tri-O-acetyl-beta-D-erythro-pentanosyl)-8-oxo-7,8-dihydroguanine with one-electron oxidants at pH 2-4 was used as a model for duplex DNA oxidation of OG residues. (1)H NMR and H,H COSY NMR studies in CD(3)OD along with LC-ESI-MS/MS fragmentation analysis are consistent with the assignment of the M - 10 species as a mixture of two pH-dependent equilibrating isomers, a guanidinohydantoin (Gh) and an iminoallantoin (Ia) nucleoside, both present as mixtures of epimers at the C5 position of the hydantoin ring, i.e., four total isomers are formed. The Gh/Ia mixture is formed from hydration and decarboxylation of the initially formed intermediate 5-hydroxy-8-oxo-7,8-dihydroguanosine, a species that is also produced by four-electron oxidation (e.g., singlet oxygen) of guanosine. The product mixture can be further oxidized to a species designated Ia(ox), a hydrolytically unstable material at pH 7 that has been characterized by ESI-MS and (1)H NMR. Competition studies with 8-oxo-7,8-dihydroadenosine placed the redox potential of Gh/Ia at about 1.0 V vs NHE. These studies provide important information concerning the structures of lesions obtained when OG, a "hot spot" for oxidative damage, serves as a "hole trap" in long-range electron-transfer studies.

A liquid chromatographic (LC) method was developed for the determination of allantoin, uric acid, and indoxyl sulfate in mammalian urine contaminated packaging material including paper bagging, corrugated cardboard, grayboard, and burlap bagging. The procedure involves solvent extraction and isolation of the 3 analytes by reversed-phase LC with ultraviolet detection at 225 nm for allantoin and 286 nm for uric acid and indoxyl sulfate. The composition of authentic mammalian urine such as mouse, rat, cat, dog, and human were also determined with regard to the 3 compounds of interest. A linear concentration range of 0.11-20.4, 0.02-10.0, and 0.04-30.0 microg/mL was obtained for allantoin, uric acid, and indoxyl sulfate, respectively. Limits of detection (LOD) and quantitation (LOQ) were 0.0104 and 0.0345 microg/mL for allantoin; 0.0018 and 0.0060 microg/mL for uric acid; and 0.0049 and 0.0165 microg/mL for indoxyl sulfate, respectively. Interday relative standard deviation values for a mixture of standard allantoin, uric acid, and indoxyl sulfate (n = 5) were 0.97, 0.80, and 0.94%, respectively. Analyte composition for 5 types of authentic mammalian urine varied from 0.19-6.88 mg/mL allantoin; 0.08-0.57 mg/mL uric acid; and 0.03-0.78 mg/mL indoxyl sulfate. Analyte content for 8 samples including 2 samples each for paper, cardboard, grayboard, and burlap bagging each contaminated with mouse or rat urine ranged from

A new HPLC method using a Polyhydroxyethyl A column involving hydrophilic interaction chromatography (HILIC) is described for the simultaneous determination of urea, allantoin and lysine pyroglutamate in a cosmetic cream. Validation of the method was accomplished with respect to linearity, repeatability and limits of detection/quantification. Compound recoveries approach 100% with acceptable RSD values. The method is very simple since no derivatisation is necessary. Furthermore, it allows the rapid and direct chromatographic analysis of urea and hence could provide an alternative to other methods used to determine this compound in biological or cosmetic samples.

A practical one-step high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of hypoxanthine, uric acid and allantoin in small (4 microL) microdialysis samples. The rationale for this work was the current interest in hypoxanthine as a marker for energy perturbation in hypoxia/ ischemia, in uric acid as an endogenous antioxidant, and in allantoin as a marker for in vivo formation of reactive oxygen species (ROS). The method is based on ion pairing reversed phase chromatography and UV detection. The coefficient of variance for within and between run imprecision was generally below 5%, somewhat higher for concentrations close to the detection limit (0.4-1.0 pmoles). Recoveries ranged from 89 to 102% and linearity was observed in the concentration range from 0.25 to 25.0 mmol/L. There was an excellent correlation between the present method and available reference methods. The method was applied to cerebral microdialysis samples from a patient with severe subarachnoid haemorrhage complicated by secondary ischemia leading to cerebral infarction. The secondary ischemia was associated with an increase of hypoxanthine followed by increasing allantoin and uric acid levels. We submit that this pattern of chemical changes indicates increased ROS formation produced by secondary ischemia. The HPLC method appears to be a useful tool for studying changes of hypoxanthine, uric acid and allantoin levels in microdialysis samples.

Allantoin and allantoic acid are investigated in the faeces and tissues of the developing sixth instar larva of the moth, Orthaga exvinacea. The nitrogen excreted as allantoin and allantoic acid is compared with nitrogen excreted as uric acid and ammonia. The larva excretes 2.35-5.14 mumol/g allantoin and 0.74-1.34 mumol/g allantoic acid which account for 0.83 to 2.39% and 0.23 to 0.53%, respectively, of the excreted total nitrogen. Allantoin and allantoic acid are found to be minor nitrogenous end-products of the larva. Allantoin and allantoic acid are also present in the haemolymph and fat body of the larva in varying concentrations. The level of allantoin in the haemolymph shows a negative correlation with the allantoin concentration of faeces and fat body. The allantoin is found to be stored in the fat body at a low level. The results of the present study also indicate the coexistence of uric acid storage and uricolysis.

A rapid and simple method for the determination of allantoin in pharmaceuticals by reversed-phase ion-pair high-performance liquid chromatography using an ODS column was presented. In general, it is difficult to retain allantoin to the ODS column owing to its very low hydrophobicity. We solved these problems by the use of a Tris-HCl buffer (pH 7.5) containing tetra-n-hexyl-ammonium bromide (THAB) as an ion-pair reagent for the mobile phase. Comparatively low concentrations of Tris-HCl buffer (0.9 mM) and THAB (0.5 mM) gave a high capacity factor (k'). As a results of the examination of the chromatographic behavior, it is confirmed that the retention mechanism of allantoin to the ODS column on the present method was not the ion-pair mode, but the ion-exchange mode. Calibration curves for allantoin showed a good linearity in the range of 10 to 400 micrograms/ml (r = 0.9999). The reproducibility (R.S.D., n = 6) was invariably good (0.37%). The lowest concentration of allantoin for the determination was 200 ng per 20 microliters of injection. The present method was successfully applied to the determination of allantoin in commercial eyedrops with good recovery (99.4%). It was found that allantoin in pharmaceuticals could be determined by the present method in short time and without any complicated derivatization.

Determination of allantoin in bovine milk based on high-performance liquid chromatography (HPLC) is described. Following dilution and filtration, milk samples were analysed directly. Separation and quantification of allantoin was achieved using a Spherisorb 5 NH2 column (250 x 4.6 mm ID), acetonitrile-water (90:10, v/v) mobile phase at a flow-rate of 2.0 ml min(-1), temperature 20 degrees C and monitoring the effluent at 214 nm. Total analysis time was 10 min. Recovery of allantoin added to milk was 97 (+/-3.7, n = 30)%. Lowest detectable concentration was 1 micromol l(-1). Within-day and between-day variability were less than 3%. Advantages of improved retention and separation of allantoin, and less complicated sample preparation exist over current methods.

Allantoin, the oxidation product of uric acid (UA), can be used as an in vivo marker of free radical generation. The aims of the present study were to evaluate the allantoin changes in plasma and bronchoalveolar lavage fluid (BALF) as well as to examine plasma levels of ascorbic acid (AA) and its oxidation product, dehydroascorbic acid (DHAA), in infants with or without chronic lung disease (CLD) during the first week of life. The study population was 20 infants of 24-30 weeks gestation, comprising 10 who subsequently developed CLD and 10 without CLD. In the CLD infants, the plasma allantoin/UA ratio showed a significant increase after day 1 and continued to increase gradually to reach a peak on day 6 (6.5 +/- 4.1% for CLD and 2.1 +/- 0.9% for non-CLD infants). The allantoin/UA ratio in BALF was also higher in CLD infants and the difference reached significance on days 4-6 (41.2 +/- 15.8% for CLD and 11.7 +/- 9.9% for non-CLD infants). In contrast to allantoin, the plasma DHAA/AA ratio did not differ between the 2 groups throughout the study period. Our findings that the allantoin/UA ratios were significantly higher in CLD than non-CLD infants not only in plasma but also in BALF, and that the intergroup differences of this ratio in both plasma and BALF was more prominent in the latter half of the first week of life further confirm our previous speculation that oxygen radicals are involved in the development of neonatal CLD.

The quantitative comparisons of Water-soluble extract, alcohol-soluble extract and allantoin in crude and three processed products of Dioscorea opposita is carried out by the method recorded in Pharmacopoeia and TLCS respectively. As a result, the changes of water-soluble extract and alcohol-soluble extract during the four samples are similar. It is the hightest in the processed product stir-fried with soil and lowest in the crude. But for allantoin, it is the highest in the processed product stir-fried with wheat bran and lowest in that stir-fried with no material. It is suggested that the contents between water-soluble extract, alcohol-soluble extract and allantoin are not interrelated. It shall be considered to increase the content of allantoin as a quality control index to control the quality of the processed products.