Unveiling characteristic metabolic accumulation over enzymatic-catalyzed process of Tieguanyin oolong tea manufacturing by DESI-MSI and multiple-omics.

To achieve an integrative understanding of the spatial distribution and chronological flavoring compounds accumulation, desorption-electrospray-ionization coupled mass-spectrometry-imaging (DESI-MSI) and multi-omics techniques were performed on the leaf samples collected from the enzymatic-catalyzed-process (ECP) stage of Tieguanyin oolong tea manufacturing. The result of DESI-MSI visualization indicated transform or re-distribution of catechins, flavonols and amino acids were on-going attributing to the multi-stress over ECP stage. Out of identified 2621 non-volatiles and 45,771 transcripts, 43 non-volatiles and 12 co-expressed pathways were screened out as biomarkers and key cascades in response to adverse conditions. The targeted metabolic analysis on the characteristic flavoring compounds showed that the accumulations of free amino acids were enhanced, while catechins, flavonol glycosides, and alkaloids exhibited dynamic changes. This result suggests withering and turning-over process are compatible and collectively regulate the metabolic accumulation and development of flavoring metabolites, facilitating to the development of characteristic quality of Tieguanyin tea.

A review of the pharmacological action and mechanism of natural plant polysaccharides in depression.

Depression is a prevalent mental disorder. However, clinical treatment options primarily based on chemical drugs have demonstrated varying degrees of adverse reactions and drug resistance, including somnolence, nausea, and cognitive impairment. Therefore, the development of novel antidepressant medications that effectively reduce suffering and side effects has become a prominent area of research. Polysaccharides are bioactive compounds extracted from natural plants that possess diverse pharmacological activities and medicinal values. It has been discovered that polysaccharides can effectively mitigate depression symptoms. This paper provides an overview of the pharmacological action and mechanisms, intervention approaches, and experimental models regarding the antidepressant effects of polysaccharides derived from various natural sources. Additionally, we summarize the roles and potential mechanisms through which these polysaccharides prevent depression by regulating neurotransmitters, HPA axis, neurotrophic factors, neuroinflammation, oxidative stress, tryptophan metabolism, and gut microbiota. Natural plant polysaccharides hold promise as adjunctive antidepressants for prevention, reduction, and treatment of depression by exerting their therapeutic effects through multiple pathways and targets. Therefore, this review aims to provide scientific evidence for developing polysaccharide resources as effective antidepressant drugs.

Research progress on the chemical components and pharmacological effects of Physalis alkekengi L. var. franchetii (Mast.) Makino.

Physalis Calyx seu Fructus is the dry calyx or the calyx with fruit of the Solanaceae plant Physalis alkekengi L. var. franchetii (Mast.) Makino, with a long history of use in medicine and food. However, despite its many potential therapeutic and culinary applications, P. alkekengi is not being exploited for these applications on a large scale. This study analysed various research related to the different chemical components of P. alkekengi, including steroids, flavonoids, alkaloids, phenylpropanoids, sucrose esters, piperazines, volatile oils, polysaccharides, amino acids, and trace elements. In addition, research related to the pharmacological activities of P. alkekengi, including its anti-inflammatory, anti microbial, antioxidative, hypoglycaemic, analgesic, anti-tumour, and immunomodulatory effects were investigated. Research articles from 1974 to 2023 were obtained from websites such as Google Scholar, Baidu Scholar, and China National Knowledge Infrastructure, and journal databases such as Scopus and PubMed, with the keywords such as Physalis alkekengi, components, effects, and activities. This study aims to provide a comprehensive understanding of the progress of phytochemical and pharmacological research on the phytochemical and pharmacological aspects of P. alkekengi and a reference for the better exploitation of P. alkekengi in the food and pharmaceutical industries.

An integrated metabolomic and transcriptomic analysis reveals the dynamic changes of key metabolites and flavor formation over Tieguanyin oolong tea production.

To interpret the formation characteristic flavor during oolong tea manufacturing process, the dynamic changes of key flavor components in samples from various processing steps of Tieguanyin oolong tea production were investigated using widely-targeted metabolomic and the transcriptomic approaches. As a result, a total of 1078 metabolites were determined, of which 62 compounds were identified as biomarkers significantly changed over the manufacturing process. Quantitative determination of the total 50,343 transcripts showed 7480 of them were co-expressed different genes. Glutamic acid served as a critical metabolism hub and a signaling molecule for diverse stress responses. Additionally, the targeted quantification results showed that the contents of catechins and xanthine alkaloids in dried tea were dramatically decreased by 20.19% and 7.15% respectively than those in fresh leaves, which potentially contributed to the alleviation of astringent or bitter palates, promoting the characteristic mellow and rich flavor of Tieguanyin oolong tea.

The Impact of Different Withering Approaches on the Metabolism of Flavor Compounds in Oolong Tea Leaves.

In this study, complementary metabolomic and proteomic analyses were conducted on the solar- and indoor-withered oolong tea leaves, and freshly plucked leaves as the control, for the purpose to reveal the mechanisms underlying the initial formation of some flavor determinants during the early stage of oolong tea processing. As a result, a total of 978 non-volatile compounds and 152 volatile compounds were identified, the flavonoids and several esters were differently accumulated in various tea samples. In total, 7048 proteins were qualitatively and quantitatively determined, the analysis on pathway enrichment showed that phenylpropanoid, flavonoid metabolisms, and protein processing in endoplasmic reticulum were the major pathways discriminating the different tea samples. The joint protein-metabolite analysis showed that the multiple stresses such as dehydration, heat, and ultra-violet irradiation occurred during the withering step induced the dynamic and distinct changes in the biochemical network in the treated leaves compared to fresh leaves. The significant decreases in flavonoids, xanthine alkaloids, and several amino acids contributed to the alleviation of bitter or astringent taste of withered leaves, although the decomposition of L-theanine resulted in the loss of umami flavor over the solar-withering step. Moreover, the fruity or floral aromas, especially volatile terpenoids and phenylpropanoids/benzenoids, were retained or accumulated in the solar withered leaves, potentially aiding the formation of a better characteristic flavor of oolong tea made by indoor withered tea leaves. Distinct effects of solar- and indoor-withering methods on the flavor determinant formation provide a novel insight into the relationship between the metabolite accumulation and flavor formation during the withering step of oolong tea production.

The stress-induced metabolites changes in the flavor formation of oolong tea during enzymatic-catalyzed process: A case study of Zhangping Shuixian tea.

To interpret the environmental stresses induced dynamic changes of volatile and non-volatile constitutes in oolong tea leaves during enzymatic-catalyzed processes (ECP), metabolomic and proteomic studies were carried out using the processed leaf samples collected at the different stages of ECP for Zhangping Shuixian tea manufacture. Non-processed leaves were applied as control. Out of identified 980 non-volatiles and 157 volatiles, 40 non-volatiles and 8 volatiles were screened out as biomarkers, respectively. The integrated analysis on metabolites-proteins showed that phenylpropanoid biosynthesis, flavonoid biosynthesis, and phenylalanine metabolism were significantly enriched and highly correlated to the dynamic changes of key metabolites during ECP stage. A biological pathway network was constructed to illuminate the enzymatic-catalyzed production of critical flavoring compounds, including carbohydrates, amino acids, flavonoids, and volatile phenylpropanoids/benzenoids. The electronic-sensory analyses indicated leaf dehydration and mechanical wounding occurred over the sun-withering and turning-over steps are indispensable to form characteristic flavor of Shuixian tea.

Enhanced activity towards oxygen electrocatalysis for rechargeable Zn-air batteries by alloying Fe and Co in N-doped carbon.

Large-scale application of rechargeable Zn-air batteries requires low-cost electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as alternatives to noble metals. Herein, FeCo nanoparticles embedded in N-doped carbon (FeCo/N-C) were prepared by a two-step pyrolysis route. FeCo/N-C exhibits excellent activities toward both the ORR (half-wave potential of 0.84 V) and OER (overpotential of 345 mV at 10 mA cm-2), which are comparable to those of commercial Pt/C and RuO2, and by far exceeding their counterparts Fe/N-C and Co/N-C. Furthermore, the FeCo/N-C catalyst was evaluated in a rechargeable Zn-air battery for the full-cell test. The FeCo/N-C based battery is more durable with a smaller round-trip overpotential after 800 cycles than the battery using an expensive Pt/C + RuO2 mixture catalyst.

Structural characterization of the metabolites of orally ingested hederasaponin B, a natural saponin that is isolated from Acanthopanax senticosus leaves by liquid chromatography-mass spectrometry.

Plant saponins are important natural product with biologically active. However, the metabolism of these compounds has rarely been studied due to their low bioavailability and the complexity of their metabolite structures. In this study, ultra-performance liquid chromatography/Fusion Lumos Orbitrap mass spectrometry was used to analyze the metabolites of hederasaponin B in vivo, and its possible metabolic pathways were proposed. After oral administration of the parent drug, a total of 47 metabolites are identified in rat feces (42), urine (11), and plasma (9) samples. These metabolites resulted from the metabolic processes in phases I and II reactions involved in deglycosylation, hydroxylation, acetylation, oxidation, gluconalciation and glycosylations. Deglycosylation is the main metabolic pathway (accounts for 52.46 % of all metabolites in feces samples). Among the identified metabolites, four were glycosylated (deprotonated precursors at m/z = 1335.7, 1365.7, 1467.9, and 1379.6) with higher molecular weight than the parent drug . These glycosylated compounds account for 11.55 % of the metabolites in rat feces according to the semi-quantitative chromatographic peak areas. To sum up, the results of this study provide a basis for further understanding the metabolism of plant saponins in vivo.

Confidence intervals for the Youden index and its optimal cut-off point in the presence of covariates.

In medical diagnostic studies, the Youden index is a summary measure widely used in the evaluation of the diagnostic accuracy of a medical test. When covariates are not considered, the diagnostic accuracy of the test can be biased or misleading. By incorporating information from covariates using linear regression models, we propose generalized confidence intervals for the covariate-adjusted Youden index and its optimal cut-off point. Furthermore, under heteroscedastic regression models, we propose various confidence intervals for the covariate-adjusted Youden index and its optimal cut-off point. Extensive simulation studies are conducted to evaluate the finite sample performance of various confidence intervals for the Youden index and its optimal cut-off point in the presence of covariates. To illustrate the application of our recommended methods, we apply the methods to a dataset on postprandial blood glucose measurements.

Rapid screening and characterization of triterpene saponins in Acanthopanax senticosus leaves via untargeted MSAll and SWATH techniques on a quadrupole time of flight mass spectrometry.

This paper focused on untargeted MSAll, also called MSE, and sequential window acquisition of all theoretical fragment-ion spectra (SWATH) fragmentations for comprehensive structural characterization of triterpene saponins (TSs) in leaves of Acanthopanax senticosus through ultra-high performance liquid chromatography electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF). [M+H]+, [M + NH4]+ and [M + Na]+ precursor ions and the corresponding fragment ions were collected simultaneously in energy-resolved MSAll. SWATH fragmentation was applied as a comparable and complementary method for resolving co-eluting species. A workflow based on MSAll and SWATH fragmentations was constructed for comprehensive structural characterization and rapid discovery of TSs in leaves of A. senticosus. As a result, 89 TSs, along with 14 sapogenins, were unambiguously characterized or tentatively identified. Of these, 33 compounds were characterized as potentially new compounds, including the first report of malonyl-saponin in genus Acanthopanax. This study aimed to systematically analyze TSs in leaves of A. senticosus, and the results are significant for the utilization of A. senticosus leaves.

Partial Youden index and its inferences.

In medical diagnostic research, medical tests with continuous values are widely employed to distinguish between diseased and non-diseased subjects. The diagnostic accuracy of a medical test can be assessed by using the receiver operating characteristic (ROC) curve of the test. To summarize the ROC curve and determine an optimal cut-off point for test results, the Youden index is commonly used. In particular, the Youden index is optimized over the entire range of values for sensitivity and specificity, which determine the ROC space. However in clinical practice, one may only be interested in the regions of the ROC curve that correspond to low false-positive rates or/and high sensitivities. In this paper, a new summary index for the ROC curve, called the "partial Youden index", is defined on regions of the ROC space in which sensitivity/specificity values are of practical interest. The traditional Youden index is a special case of the partial Youden index. Various parametric and non-parametric interval estimation methods are proposed for the partial Youden index. Extensive simulation studies are conducted to evaluate the finite sample performances of the proposed methods. A real example is used to illustrate the application of the new methods.

Separation and confirmation of nine Enterobacteriaceae strains that carry the blaNDM-1 gene.

The aim of the present study was to confirm the existence of carbapenem-resistant Enterobacteriaceae carrying the blaNDM-1 gene in clinics in Hainan province, China. Collected clinical bacterial isolates that were Enterobacteriaceae strains suspected of producing carbapenemase were used as experimental strains. Drug resistance to imipenem, meropenem and other antibacterial agents was tested. Imipenem/imipenem inhibitor (IP/IPI) E-testing was conducted to identify the bacterial strains that produced metallo-ß-lactamases. The blaNDM-1 drug resistance gene was amplified by polymerase chain reaction (PCR), and agarose gel electrophoresis (AGE) and sequencing were conducted to identify the products. The species of the strains carrying the blaNDM-1 gene were determined using a biochemical identification system. Through the IP/IPI E-test, 21 of the 30 collected Enterobacteriaceae strains were found to be positive, indicating that 70% of the strains produced metallo-ß-lactamases. Following blaNDM-1 gene PCR amplification, AGE and sequencing tests confirmed that nine of the strains carried the blaNDM-1 drug resistance gene. The biochemical identification system indicated that four of the strains were Klebsiella pneumoniae, two were Escherichia coli, two were Enterobacter cloacae and one was Enterobacter aerogenes. Drug susceptibility testing in vitro demonstrated that the strains were 100% resistant to a broad spectrum antibiotic plus lactamase inhibitor, cephalosporins and carbapenems. However, they had high sensitivity rates to polymyxin B and tigecycline of 100 and 88.9%, respectively. The sensitivity rate to amikacin was also high at 77.8%, whereas sensitivity to ciprofloxacin and gentamicin was moderate at rates of 44.4 and 33.3% respectively. This clinical study of Enterobacteriaceae strains that carry the blaNDM-1 gene in Hainan shows a bacterial tolerance that is different from that in previous studies, which requires further in-depth study.