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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.

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.)

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.

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 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.

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.

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.)

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.