Chemical Foundation Research Articles

Intestine vs. Liver ？ Uncovering the Hidden major Metabolic organs of Silybin in Rats.

Silybin, extracted milk thistle, was a flavonolignan compound with hepatoprotective effect. Now it is commonly used in dietary supplements, functional foods, and nutraceuticals. However, the metabolism of silybin has not been systematically characterized in organisms to date. Therefore, we established a novel HPLC-Q-TOF/MS method to analyze and identify the prototype and metabolites of silybin in rats. Totally, 29 (out of 32) new metabolic pathways and 56 (out of 59) unreported metabolite products were detected. Moreover, we found that the liver had a high first-pass effect of 63.30%{plus minus}13.01 for silybin and only one metabolite was detected. And the metabolites identified in gastrointestinal tract possessed 88% of all (52 out of 59). At the same time, the high concentration of silybin in the livers also indicated large amounts of silybin may be accumulated in liver instead of being metabolized. These results indicated the primary metabolizing organ of silybin in rats was intestine rather than liver, which would also offer solid chemical foundation for exploring more promising health care products of silybin. Significance Statement This study confirmed the main metabolism place of silybin in rats were gastrointestinal tracts instead of livers and the intestinal microbes were closely involved. Then 29 (out of 32) metabolism pathways and 56 (out of 59) metabolites were identified for the first time in rats. And to further study the liver disposition of silybin, its hepatic first-pass effect was determined for the first time.

Interbacterial Biofilm Competition through a Suite of Secreted Metabolites.

Polymicrobial biofilms are ubiquitous, and the complex interspecies interactions within them are cryptic. We discovered the chemical foundation of antagonistic interactions in a model dual-species biofilm in which Pseudomonas aeruginosa inhibits the biofilm formation of Agrobacterium tumefaciens. Three known siderophores produced by P. aeruginosa (pyoverdine, pyochelin, and dihydroaeruginoic acid) were each capable of inhibiting biofilm formation. Surprisingly, a mutant that was incapable of producing these siderophores still secreted an antibiofilm metabolite. We discovered that this inhibitor was N5-formyl-N5-hydroxy-l-ornithine (fOHOrn)─a precursor in pyoverdine biosynthesis. Unlike the siderophores, this inhibitor did not appear to function via extracellular metal sequestration. In addition to this discovery, the compensatory overproduction of a new biofilm inhibitor illustrates the risk of pleiotropy in genetic knockout experiments. In total, this work lends new insight into the chemical nature of dual-species biofilm regulation and reveals a new naturally produced inhibitor of A. tumefaciens biofilm formation.

Optimization of the synthesis of BET BD2 selective inhibitor XY153.

XY153 is a promising BET BD2 inhibitor with an IC50 value of 0.79 nM against BRD4 BD2. It shows 354-fold selectivity over BRD4-BD1 and 6-fold selectivity over other BET BD2 domains. However, the reported synthesis route of XY153 and its derivatives are extremely poor-yielding. After the synthesis of three key fragments, XY153 can only be obtained with a yield of 1.3 % in the original four-step reaction. In this study, we reported a three-step alternative route in the synthesis process of XY153. The reaction conditions for this route were thoroughly investigated and optimized, resulting in a significantly improved yield of 61.5 %. This efficient synthesis route establishes a robust chemical foundation for the rapid synthesis of XY153 derivatives as BET BD2 inhibitors in the near future.

Determination of 44 major components and chemical profiling of saccharide in Chinese medicinal formula Lanqin Oral Liquid.

Lanqin Oral Liquid (LQL) is a traditional Chinese medicine preparation (TCMP) containing five herbal medicines and has been commonly used for the treatment of pharyngitis and hand-foot-and-mouth disease in clinic. The material basis of LQL has been reported in our previous study, but the contents of the major components and the features of saccharide in LQL are still unclear. This study aimed to establish accurate and rapid methods for the quantification of the major components and profiling of saccharide in LQL. The quantitative results combined with similarity evaluation were applied to improve the quality control of LQL. An ultra-high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-QQQ-MS) method wasutilised to determine 44 major components. Cosine similarity was used to evaluate the similarities among 20 batches of LQL based on the quantitative results of 44 major components. The physicochemical properties, structure, composition, and contents of saccharide in LQL were detected by a combination of chemical and instrumental analysis. A total of 44 compounds, including flavonoids, iridoid glycosides, alkaloids, and nucleosides, were accurately determined. The 20 batches of LQL were remarkably similar (> 0.95). In addition, d-glucose, galactose, d-glucuronic acid, arabinose, and d-mannose were detected in saccharide of LQL. The contents of saccharide in LQL were 13.52-21.09 mg/ml. The established methods can be applied for the comprehensive quality control of LQL, including characterisation of saccharide and quantification of representative components. Our study will provide a robust chemical foundation for disclosing the quality markers of its therapeutic effect.

A comparative study of Liandan Xiaoyan Formula metabolic profiles in control and colitis rats by UPLC-Q-TOF-MS combined with chemometrics

Liandan Xiaoyan Formula (LDXYF) is a traditional Chinese medicine prescription (TCMP) consisting of Herba Andrographis (dried herb of Andrographis paniculata) and Picrasmae ramulus et folium (dried twiggeries and leaves of Picrasma quassioides). It is used to treat diarrhea, acute gastroenteritis, colitis, and dysentery, among other inflammatory gastrointestinal diseases. However, because of less research on the in vitro chemical composition and holistic metabolism of LDXYF, in vivo mechanisms of action and quality control of LDXYF have not yet been fully assessed due to the lack of studies into its bioactive components. In this study, ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was established for comprehensive analysis of chemical compounds of LDXYF and their metabolites in serum and urine samples of control and colitis rats. As a result, totally 94 compounds in LDXYF were unambiguously identified or tentatively characterized. And a total of 91 LDXYF-related xenobiotics were characterized, including 61 (16 prototypes and 45 metabolites) in serum, and 72 (26 prototypes and 46 metabolites) in urine. Besides, we compared the exposure of metabolites in normal and colitis rats by chemometrics and summarize similarities and differences of metabolic pathways of mainly compounds in normal and colitis conditions, and found that in control and colitis conditions, alkaloids predominantly went through phase I reaction combined phase II reaction (hydroxylation and sulfation, hydroxylation and glucuronidation, demethylation and glucuronidation), while the major metabolic reaction of diterpene lactones were phase Ⅱ reactions (glucuronidation, sulfation). And there were no significant differences in metabolic pathways between control and colitis groups, just the exposure of prototype and their metabolites absorbed into serum or excreted through the urine were different, and 17 alkaloids and 6 diterpene lactone prototypes and their metabolites in serum could be considered as potential pharmacodynamic substances. A comprehensive analysis of the compounds and metabolic characteristics of LDXYF was conducted in our study, and the results laid the chemical foundation for further research into effective substances and the action mechanism of LDXYF.

Comprehensive chemical profile and quantitative analysis of the Shabyar tablet, a traditional ethnic medicine prescription, by ultra-high-performance liquid chromatography with quadrupole-orbitrap high-resolution mass spectrometry.

The Shabyar tablet is commonly used as a traditional ethnic medicine prescription for the treatment of night blindness, poor vision, and headaches. However, the chemical components of the Shabyar tablet have not been holistically explored, which seriously hinders the discovery of the activity. This study qualitatively and quantitatively investigated the overall chemical profile of the Shabyar tablet using ultra-high-performance liquid chromatography hyphenated with quadrupole-orbitrap high-resolution mass spectrometry. Altogether, 170 chemical components, including 59 flavonoids, 78 organic acids, 12 anthranones, three anthraquinones, one naphthalene, and 17 other compounds were tentatively identified and attributed, with 40 among these being unambiguously characterized in comparison with their corresponding authentic standards. To further determine the major representative constituents of the Shabyar tablet, a quantitative method was used for the simultaneous analysis of 33 characteristic components in Shabyar samples. The results were validated in terms of linearity, precision, repeatability, stability, and recovery. This newly developed approach could be successfully employed for evaluating the holistic quality of crude extracts and Chinese medicines in the Shabyar compound tablet and provide a solid chemical foundation for additional investigations on in vivo pharmacodynamics and therapeutic mechanisms to identify the potential effective components of traditional medicines.

Site-Specific Synthesis of N4-Acetylcytidine in RNA Reveals Physiological Duplex Stabilization.

N4-Acetylcytidine (ac4C) is a post-transcriptional modification of RNA that is conserved across all domains of life. All characterized sites of ac4C in eukaryotic RNA occur in the central nucleotide of a 5'-CCG-3' consensus sequence. However, the thermodynamic consequences of cytidine acetylation in this context have never been assessed due to its challenging synthesis. Here, we report the synthesis and biophysical characterization of ac4C in its endogenous eukaryotic sequence context. First, we develop a synthetic route to homogeneous RNAs containing electrophilic acetyl groups. Next, we use thermal denaturation to interrogate the biochemical effects of ac4C on duplex stability and mismatch discrimination in a native sequence found in human rRNA. Finally, we demonstrate the ability of this chemistry to incorporate ac4C into the complex modification landscape of human tRNA and use duplex melting to highlight an enforcing role for ac4C in this unique sequence context. By enabling ex vivo biophysical analyses of nucleic acid acetylation in its physiological sequence context, these studies establish a chemical foundation for understanding the function of a universally conserved nucleobase in biology and disease.

The Protective Effect of Ethyl Acetate and n-Butanol Fractions of Wine-Steamed Ligustri Lucidi Fructus on Diabetic Nephropathy in Rats.

Ligustri Lucidi Fructus (LLF), the dry and ripe fruit of Ligustrum lucidum W. T. Aiton (Oleaceae), is a traditional Chinese medicine for nourishing the liver and kidney in clinics for thousands of years. Wine-steamed Ligustri Lucidi Fructus (WLL) can alleviate coolness and smoothness of LLF and enhance the function of nourishing the liver and kidney, so ancient and modern medicine usually used it in clinics. First of all, we prepared the extracts of different polar fractions of WLL to explore the effective fractions and potential mechanisms of WLL in the treatment of diabetic nephropathy (DN). Then, HPLC method was used to determine the contents of 12 active components in WLL and its different polar components. Finally, the potential relationship between 12 active components and physicochemical parameters of DN rats was explored. The pharmacological experiments showed that WLL, ethyl acetate (EtOAc), and n-butanol (n-BuOH) extracts not only significantly alleviated the clinical symptoms and kidney damage of DN rats but also had obvious anti-inflammatory and antioxidant effects. In addition, the results of HPLC analysis showed that the 12 active components of WLL mainly existed in the extracts of EtOAc and n-BuOH. The Pearson correlation analysis showed 12 active components and physicochemical parameters had different degrees of correlation. In conclusion, we proved that the extracts of EtOAc and n-BuOH were the effective fractions of WLL in treating DN in rats, and they could regulate the levels of inflammatory cytokines and decrease oxidation stress, which provides a basis for further research on the mechanism of WLL in treating DN and provides a pharmacological and chemical foundation for the development of new anti-DN drugs.

Qualitative and quantitative analysis of the chemical profile for Gualou-Xiebai-Banxia decoction, a classical traditional Chinese medicine formula for the treatment of coronary heart disease, by UPLC-Q/TOF-MS combined with chemometric analysis

Gualou-Xiebai-Banxia decoction (GXB) is one of the famous classical traditional Chinese Medicine (TCM) formula for the treatment of chest stuffiness and pains syndrome in Chinese medicine, i.e., coronary heart disease (CHD) in modern medicine. Being compared with Gualou-Xiebai Baijiu-decoction which only consists of Trichosanthis Pericarpium (TP), Allii Macrostemonis Bulbus (AMB) and wine, GXB is composed of another one additional herbal medicine, Pinellinae Rhizoma Praeparatum (PRP), and is more suitable to treat severe atherosclerosis and dyslipidemia. However, the comprehensive chemical composition of GXB is still unclear, which has seriously hindered the discovery of its effective components for improving the clinical symptoms of CHD. The present study aimed to investigate the overall chemical profile of GXB qualitatively and quantitatively by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS), and further explore the chemical contribution of PRP to this formula combined with chemometric approach. First, a total of 151 components, including steroidal saponins, flavonoids, triterpenoids, nitrogenous and other types components, were detected and characterized by UPLC-Q/TOF-MS in GXB. Then, flavonoids and nitrogenous could be qualitatively observed enrichment in GXB compared to those in GXB-dePRP (GXB deducted PRP in the formula). Furthermore, 19 characteristic components were selected for quantitative comparison between GXB and GXB-dePRP by UPLC-MS/MS combined with chemometric method. These findings indicated that steroidal saponins were the most abundant components in GXB, while the introduction of PRP could not only enrich the structural types of chemical compounds in this formula, but also increase the abundance of active components from other composed herbal medicines, TP and AMB. Taken together, this study developed and validated sensitive and practical methods for qualitative and quantitative analysis of GXB, and clarified the chemical contribution of PRP to this formula. These results laid a solid chemical foundation for further in vivo disposal investigation to screen out the potential effective components as well as therapeutic mechanism research of GXB.

Preferential DNA Polymerase β Reverse Reaction with Imidodiphosphate.

DNA replication and repair reactions involve the addition of a deoxynucleoside monophosphate onto a growing DNA strand with the loss of pyrophosphate. This chemical reaction is also reversible; the addition of pyrophosphate generates a deoxynucleoside triphosphate, thereby shortening the DNA by one nucleotide. The forward DNA synthesis and reverse pyrophosphorolysis reactions strictly require the presence of divalent metals, usually magnesium, at the reactive center as cofactors. The overall equilibrium enzymatic reaction strongly favors DNA synthesis over pyrophosphorolysis with natural substrates. The DNA polymerase β chemical reaction has been structurally and kinetically characterized, employing natural and chemically modified substrates. Substituting an imido-moiety (NH) for the bridging oxygen between Pβ and Pγ of dGTP dramatically decreased the overall enzymatic activity and resulted in a chemical equilibrium that strongly favors the reverse reaction (i.e., K ≪ 1). Using QM/MM calculations in conjunction with the utilization of parameters such as quantum mechanically derived atomic charges, we have examined the chemical foundation for the altered equilibrium with this central biological reaction. The calculations indicate that the rapid reverse reaction is likely due, in part, to the increased nucleophilicity of the reactive oxygen on the tautomeric form of imidodiphosphate.

Identification and characterization of chemical constituents in Qi-Lin pills and their metabolites in rat bio-samples after oral administration using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry

Qi-Lin pill (QLP), a traditional Chinese medicine prescription (TCMP), composed of fifteen herbal medicines, has been widely used for the treatment of male infertility. However, an in-depth understanding of the chemical constituents of QLP and its in vivo metabolic study is lacking. In this study, a method using ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was established for comprehensive analysis of chemical constituents of QLP and their metabolites in plasma, urine, bile and feces after gastric perfusion. The method guaranteed the fast discovery of representative structural fragment information and provided efficient structure clues for identification based on data from MSE mode. As a result, a total of 202 constituents were unambiguously identified or tentatively characterized. In addition, a total of 203 QLP-related xenobiotics were characterized, including 41 (22 prototypes and 19 metabolites) in plasma, 144 (47 prototypes and 97 metabolites) in urine, 50 (27 prototypes and 23 metabolites) in bile and 68 (51 prototypes and 17 metabolites) in feces. The metabolism reactions included phase I reactions (demethylation, hydroxylation, deglycosylation, deoxygenation, hydrogenation, dehydration, oxidation and hydrolysis) and phase II reactions (methylation, conjugation with glucuronide and sulfate). This was the first comprehensive investigation on chemical constituents and metabolic profiles of QLP in vivo, and the results provided chemical foundation for further research on effective substances and action mechanism of QLP.

Understanding the chemical foundation and genetic mechanism of the black grain trait in quinoa by integrating metabolome and transcriptome analyses

Quinoa (Chenopodium quinoa Willd.) cultivars that produce black grains are thought to be more nutritious and contain powerful antioxidant properties, but little is known about the chemical foundation and the genetic mechanism behind this trait. In this research, widely-targeted metabolome and transcriptome analyses were employed to unveil the chemical and genetic differences between black and white quinoa cultivars. A total of 157 differentially expressed metabolites were found in the black and white quinoa cultivars. The tannins and flavonoids were present at high levels in the black quinoa grains. The tannins comprised 13 proanthocyanins, all of which could barely be detected in white grains. Proanthocyanidins are suggested to cause the black grain trait in Arabidopsis thaliana and Brassica species and are thought to produce the black grain trait, while contributing to antioxidant activity, in black grain quinoa. A total of 4620 differentially expressed unigenes were identified in the black and white quinoa grains. Structural genes associated with proanthocyanin biosynthesis, particularly DFR, LAR, LDOX and ANR, were more highly expressed in black than white grains. Genes involved in the betalain biosynthetic pathway, which competes with anthocyanin biosynthesis, showed relatively lower levels of expression in black grains. Two MYB and one MYC transcription factor related to the phenylpropane metabolic pathway displayed higher expression levels in black grains, while BvMYB1, associated with betalain biosynthesis, was not detected. This study suggested that the accumulation of proanthocyanins produces the black grain trait in quinoa, and the activation of transcription factors triggers the proanthocyanidin biosynthesis pathway.

The Protective Effect of Different Polar Solvent Extracts of Er Miao San on Rats with Adjuvant Arthritis.

Objective The aim of this study was to evaluate the antiarthritic effects of different polar solvent extracts of Er Miao San (EMS) on model rats with adjuvant arthritis (AA) and screen the effective pats of EMS in the treatment of arthritis. Methods Four different polar solvent extracts of EMS such as petroleum ether (PE), methylene chloride (CH2Cl2), ethyl acetate (EtOAc), and n-butanol (n-butanol (Results Administration of EtOAc and CH2Cl2 parts remarkably inhibited the paw swelling, decreased the index of arthritis, decreased the body weight loss, and improved the changes of histopathology. Furthermore, the concentrations of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) were significantly lower, while the anti-inflammatory cytokine (IL-10) was remarkably higher compared with that in the model group. And the result of UHPLC analysis indicated that the effective parts of EMS contain berberine and atractylodin. Conclusions EtOAc and CH2Cl2 are the effective parts of EMS that can improve arthritis. In particular, berberine and atractylodin may be responsible for the antiarthritic activity of EMS. This research provided pharmacological and chemical foundation for the application of EMS in treating rheumatoid arthritis (RA).

Two new 8-isopentenyl isoflavane derivatives from Astragalus dolichochaete diels

Astragali Radix (Huangqi) is one of the well-known traditional Chinese medicines and has been used in China for more than two thousand years. As a close species, Astragalus dolichochaete Diels was found to possess cytotoxicity during our preliminary study of Astragalus plants from Yunnan Province, China. To better understand the chemical foundation of the cytotoxicity, the major constituents of A. dolichochaete were studied. As a result, two new 8-isopentenyl isoflavane derivatives, dolichochaeteins A and B (1 and 2), together with ten known constituents were isolated, and their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. The cytotoxic activities were evaluated for the raw extract, ethyl acetate fraction, compound 2 and glyasperin H (3) against human gastric carcinoma cell line SGC-7901, human hepatoma cell line SMMC-7721 and human leukemic cell line K562. All the samples exhibited significant cytotoxicity.

Computational Analysis of Theacrine, a Purported Nootropic and Energy-Enhancing Nutritional Supplement

Herein is the first reported conceptual density functional theory (DFT) investigation of the purine alkaloid theacrine and the comparison of quantum chemical properties to the closely related stimulant caffeine. DFT global chemical reactivity descriptors (chemical hardness/softness, chemical potential/ electronegativity, and electrophilicity) and local reactivity descriptors (Fukui functions and dual descriptor) were calculated for both compounds using Spartan ‘16 software. All calculations were carried out at the B3LYP/6-31G* level of theory. Reactivity analysis of the Fukui dual descriptor calculations reveals sites of nucleophilic and electrophilic attack. The results provide a solid chemical foundation for understanding how theacrine interacts with cellular systems.

Pharmacokinetic characteristics of fourteen main components of Gegen Qinlian Decoction in rats

Animal traditional Chinese medicine has a long history of application in China, and its clinical application is very extensive. Due to the complex chemical composition in animal traditional Chinese medicine, the basis of chemical research is relatively weak, which leads to the unclear composition and toxic components of many animal Chinese medicines. The relationship between the medicinal and toxic components of animal Chinese medicine has not yet been elucidated. The non-clinical safety evaluation of animal traditional Chinese medicine mainly includes acute toxicity, long-term toxicity, safety pharmacology, reproductive toxicity, genotoxicity experiments, and experimental studies such as carcinogenicity are needed when necessary. The current preclinical safety research on animal traditional Chinese medicine is mainly based on the study for toxic animal traditional Chinese medicines. Most animal Chinese medicines have not carried out systematic preclinical and clinical safety studies. The research method is mainly focused on acute toxicity test. It is necessary to carry out systematic preclinical safety studies on animal traditional Chinese medicines, to clarify the possible side effects and its characteristics, its toxic target organs, toxic doses and poisoning mechanisms induced by different animal traditional Chinese medicines. Finally, this paper suggests that in the preclinical safety study of animal traditional Chinese medicine, in-depth research and comparison should be carried out in combination with chemical substance foundation, origin, and collection season, and the safety of "non-toxic" animal traditional Chinese medicine should be carried out when necessary. In addition, it is necessary to rationally use the cutting-edge technologies and methods of toxicology research to fully clarify the preclinical safety information of animal Chinese medicines.

Total Synthesis of (±)-Prostratin

Summary Prostratin, a highly complex diterpene natural product, is a pre-clinical candidate in developing a cure for HIV-1 infection and also a potent and selective inhibitor of several tumors. Despite nearly 40 years of progress, prostratin and related natural products still present formidable challenges for synthetic chemists. Here, we report a total synthesis of (±)-prostratin that proceeds in 23 steps from cyclopentadiene. The synthetic strategy includes rapid assembly of the tricyclic core and highly controlled establishment of the densely functionalized C ring, featuring an array of stereoselective transformations including alkoxide-guided 1,4-additions and cyclopropane formation. This work should enable further explorations of chemical and biological spaces based on prostratin and related natural products.

A Chemical Signature for Cytidine Acetylation in RNA.

N4-acetylcytidine (ac4C) is a highly conserved modified RNA nucleobase whose formation is catalyzed by the disease-associated N-acetyltransferase 10 (NAT10). Here we report a sensitive chemical method to localize ac4C in RNA. Specifically, we characterize the susceptibility of ac4C to borohydride-based reduction and show this reaction can cause introduction of noncognate base pairs during reverse transcription (RT). Combining borohydride-dependent misincorporation with ac4C's known base-sensitivity provides a unique chemical signature for this modified nucleobase. We show this unique reactivity can be used to quantitatively analyze cellular RNA acetylation, study adapters responsible for ac4C targeting, and probe the timing of RNA acetylation during ribosome biogenesis. Overall, our studies provide a chemical foundation for defining an expanding landscape of cytidine acetyltransferase activity and its impact on biology and disease.

The effect of boron addition on the deformation behavior and microstructure of β-solidify TiAl alloys

The effect of boron addition on the deformation behavior and microstructure of Ti-43Al-6Nb-1Mo -1Cr alloys have been studied in this paper. Boron addition would induce Ti2Al(P63/mmc) phase with hexagonal structure formation on the interfaces between TiB and γ phase. TiB would be the obstacles for dislocations slipping and increase the stacking fault energy. Ti2Al could also provide the chemical foundation for DRXed γ nucleation and disappear after thermal deformation. Both these two phase could promote DRXed grains nucleation to soften the alloys during thermal deformation. With the strengthen effect of boron solid solution and TiB obstacles, the microstructure evolution, phase transformation and deformation behavior are also discussed and concluded as follow.

Formation mechanism of the oolong tea characteristic aroma during bruising and withering treatment

To elucidate formation mechanism of oolong tea aroma, the released and remaining volatiles during bruising and withering treatment were analyzed using head space solid-phase microextraction/gas chromatography-mass spectrometry. An increase in proportion of the released terpenoid volatiles (TVs) along with a decrease in proportion of the released C6 green leaf volatiles (GLVs) was observed in both cultivars ‘Zhejiang139’ and ‘Foshou’. Proportion of remaining TVs also fluctuated reversely with GLVs although the level of these volatiles increased remarkably. High ratio of TVs to GLVs was the key chemical foundation of oolong tea characteristic aroma and could be regarded as a good indicator in screening cultivar for suitably producing high quality oolong tea. Combining with transcriptome analysis, increased TVs and GLVs during the treatment might be largely generated through de novo synthesis and modulated at transcript level through up-regulation of genes involved in terpenoids metabolism and enzymatic cleavage of long-chain fatty acids.