Rhodiosin from Rhodiola crenulata effectively alleviate postprandial hyperglycemia by inhibiting both the activity and production of α­glucosidase.

BACKGROUND: Effective control of postprandial blood glucose (PBG) level is essential for the prevention and treatment of diabetes and its complications. Several flavonoids have attracted much attention due to their significant PBG-lowering effects. However, there is still a certain gap in the in vivo hypoglycemic activity of most flavonoids compared to first-line drugs available on the market, and are still lack of the PBG-lowering effects of 8-hydroxyflavones and their structure-activity relationship. PURPOSE: Evaluate hypoglycemic effects of 8-hydroxyflavones from Rhodiola crenulata in vitro and in vivo, especially comparatively analyze the relationship between hypoglycemic effects and flavonoid configuration and reveal the possible mechanism of 8-hydroxyflavones in lowering hyperglycemia. METHODS: Starch, maltose, sucrose, and glucose tolerance tests in both diabetic and normal mice were used to evaluate and compare the hypoglycemic effects of 8-hydroxyflavones rhodiosin (RHS), rhodionin (RHN), and herbacetin (HBT). Molecular docking, enzyme kinetics, and immunofluorescence analysis were used to research the possible hypoglycemic mechanisms of 8-hydroxyflavones. RESULTS: RHS (5 and 10 mg/kg) could efficiently decrease PBG levels in both normal and diabetes mice. Moreover, RHS, RHN, and HBT all had significant PBG-lowering effects in transgenic diabetes mice, and the effects were equivalent to or stronger than acarbose. Further mechanism research indicated that 8-hydroxyflavones achieved PBG-lowering effects by inhibiting both the activity and production of glycosidase. Notably, we have innovatively discovered that inhibiting the expression of glycosidases rather than just their activities may be a new target for hypoglycemic drugs. CONCLUSION: We have firstly comprehensively and systematically clarified PBG-lowering effects of 8-hydroxyflavones from Rhodiola crenulata, and revealed their structure-activity relationships and hypoglycemic mechanisms. The study demonstrated that the substitution of 8-hydroxy groups in flavonoids could significantly enhance their hypoglycemic effects, which were equivalent to or stronger than commercially available drug acarbose. 8-Hydroxyflavones could be used as therapeutic or health drugs with significant potential to reduce postprandial hyperglycemia.

Extract of Silphium perfoliatum L. improve lipid accumulation in NAFLD mice by regulating AMPK/FXR signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Globally, the incidence rate and number of patients with nonalcoholic fatty liver disease are increasing, which has become one of the greatest threats to human health. However, there is still no effective therapy and medicine so far. Silphium perfoliatum L. is a perennial herb native to North America, which is used to improve physical fitness and treat liver and spleen related diseases in the traditional medicinal herbs of Indian tribes. This herb is rich in chlorogenic acids, which have the functions of reducing blood lipids, losing weight and protecting liver. However, the effect of these compounds on nonalcoholic fatty liver disease remains unclear. AIM OF THE STUDY: Clarify the therapeutic effects and mechanism of the extract (CY-10) rich in chlorogenic acid and its analogues from Silphium perfoliatum L. on non-alcoholic fatty liver disease, and to determine the active compounds. MATERIALS AND METHODS: A free fatty acid-induced steatosis model of HepG2 cells was established to evaluate the in vitro activity of CY-10 in promoting lipid metabolism. Further, a high-fat diet-induced NAFLD model in C57BL/6 mice was established to detect the effects of CY-10 on various physiological and biochemical indexes in mice, and to elucidate the in vivo effects of the extract on regulating lipid metabolism, anti-inflammation and hepatoprotection, and nontarget lipid metabolomics was performed to analyze differential metabolites of fatty acids in the liver. Subsequently, western blotting and immunohistochemistry were used to analyze the target of the extract and elucidate its mechanism of action. Finally, the active compounds in CY-10 were elucidated through in vitro activity screening. RESULTS: The results indicated that CY-10 significantly attenuated lipid droplet deposition in HepG2 cells. The results of in vivo experiments showed that CY-10 significantly reduce HFD-induced mouse body weight and organ index, improve biochemical indexes, oxidation levels and inflammatory responses in the liver and serum, thereby protecting the liver tissue. It can promote the metabolism of unsaturated fatty acids in the liver and reduce the generation of saturated fatty acids. Furthermore, it is clarified that CY-10 can promote lipid metabolism balance by regulating AMPK/FXR/SREPB-1c/PPAR-γ signal pathway. Ultimately, the main active compound was proved to be cryptochlorogenic acid, which has a strong promoting effect on the metabolism of fatty acids in cells. Impressively, the activities of CY-10 and cryptochlorogenic acid were stronger than simvastatin in vitro and in vivo. CONCLUSION: For the first time, it is clarified that the extract rich in chlorogenic acids and its analogues in Silphium perfoliatum L. have good therapeutic effects on non-alcoholic fatty liver disease. It is confirmed that cryptochlorogenic acid is the main active compound and has good potential for medicine.

Characterization of alkaloids and phenolics in Nitraria roborowskii Kom. fruit by UHPLC-triple-TOF-MS/MS and its sucrase and maltase inhibitory effects.

Nitraria roborowskii Kom (NRK), with high economic and ecological value, is mainly distributed in the Qaidam Basin, China. However, research on its chemical components and bioactivities is still rare. In this study, its chemical constituents (52) including 10 ß-carboline alkaloids, nine cyclic peptides, three indole alkaloids, five pyrrole alkaloids, eight phenolic acids and 17 flavonoids were identified tentatively using UPLC-triple-TOF-MS/MS. Notablely, one new ß-carboline alkaloid and five new cyclic peptides were confirmed using MS/MS fragmentation pathways. In addition, experiments in vitro indicated that NRK-C had strong maltase and sucrase inhibitory activities (IC50 of 0.202 and 0.103 mg/mL, respectively). Polysaccharide tolerance experiments confirmed NRK-C (400 mg/kg) was associated with decreased postprandial blood glucose (PBG) in diabetic mice. These results suggested that NRK fruit might be used as a functional ingredient in food products.

Visible-Light-Promoted Cascade Coupling of 2-Isocyanonaphthalenes with Elemental Sulfur and Amines to Construct Naphtho[2,1-d]thiazol-2-Amines.

A visible-light-induced strategy has been explored for the synthesis of naphtho[2,1-d]thiazol-2-amines through ortho-C-H sulfuration of 2-isocyanonaphthalenes with elemental sulfur and amines under external photocatalyst-free conditions. This three-component reaction, which utilizes elemental sulfur as the odorless sulfur source, molecular oxygen as the clean oxidant, and visible light as the clean energy source, provides a mild and efficient approach to construct a series of naphtho[2,1-d]thiazol-2-amines. Preliminary mechanistic studies indicated that visible-light-promoted photoexcitation of reaction intermediates consisting of thioureas and DBU might be involved in this transformation.

Copper-Catalyzed Three-Component Tandem Reaction of Alkynes, α-Diazo Esters, and TMSN3 to Access N-Substituted 1,2,3-Triazoles.

An efficient copper-catalyzed three-component tandem reaction of alkynes, α-diazo esters, and TMSN3 to construct triazoles has been developed. Through this strategy, a number of diverse N-substituted 1,2,3-triazoles were conveniently obtained in moderate to good yields from simple and readily available starting materials using K2CO3 as the base. The mechanism of the tandem Cu-catalyzed azide-alkyne cycloaddition (CuAAC) and Cu-carbenoid-participated C-N coupling reaction has been investigated.

The relationship between work-family conflict and job satisfaction for preschool teachers in rural China: a moderated mediation model.

Background: Job satisfaction for preschool teachers in rural areas has an important impact on their professional development, physical and mental health, and the development of preschool education. However, few studies have explored the factors that influence rural preschool teachers' job satisfaction. Purpose: This study aims to examine the influence of rural preschool teachers' work-family conflict on their job satisfaction, and the mediating effect of occupational identity, the moderating effect of social support. Method: Participants included 3,065 rural preschool teachers from Zhejiang Province in mainland China. Teachers completed questionnaires on work-family conflict, occupational identity, job satisfaction, and social support. The correlation and moderated mediation analyses were conducted using SPSS PROCESS. Results: (1) work-family conflict is associated with poorer job satisfaction in preschool teachers; (2) occupational identity mediates the relationship between work-family conflict and job satisfaction; and (3) a high level of social support alleviates the negative influence of work-family conflict on job satisfaction and promotes the positive effect of occupational identity on job satisfaction. Conclusion: The study revealed the negative impact of work-family conflict on preschool teachers' job satisfaction, and the protecting effect of social support, which has important implications for improving teachers' future job satisfaction.

Inhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivo.

BACKGROUND: α-Glucosidase inhibitors could effectively reduce postprandial blood glucose (PBG) levels and control the occurrence of complications of diabetes. Gallotannins (GTs) in plants have attracted much attention due to their significant α-glucosidase inhibitory activities in vitro. However, there is still a lack of systematic comparative studies to further elucidate inhibitory activities in vivo and in vitro of these compounds against α-glucosidase, especially for mammalian sucrase and maltase, and analyze their structure-activity relationship. PURPOSE: Determine the in vitro and in vivo inhibitory activities of five GTs with different number of galloyl moieties (GMs) on sucrase, maltase and α-amylase, and elucidate the relationship between α-glucosidase inhibitory activities and the number and connection mode of GMs. METHODS: Molecular docking and dynamics were used to study the binding mode and binding ability of five GTs against sucrase, maltase and α-amylase. Then, the inhibitory activities and inhibitory mechanisms of these compounds on sucrase, maltase and α-amylase in vitro were studied using inhibitory assay and enzyme inhibition kinetics. Further, the hypoglycemic effects in vivo of these compounds were demonstrated by three polysaccharides tolerance experiments on diabetes model mice. RESULTS: The results of molecular docking showed that these compounds could bind to enzymes through hydrogen bonds, hydrophobic interactions, etc. In addition, the α-glucosidase inhibition comparative studies in vitro and in vivo demonstrated that the inhibitory activities of these compounds on all three sucrase, maltase and α-amylase were ranked as TA ≈ PGG > TeGG > TGG > 1GG, and their inhibitory activities increases with the increase in the number of GMs. Moreover, the hypoglycemic effects of 1,2,3,4,6-pentagalloylglucose (PGG) and tannic acid (TA) in vitro and in vivo were also confirmed to be equivalent to or even stronger than that of acarbose. CONCLUSION: α-Glucosidase inhibitory activities in vitro and in vivo of GTs were positively correlated with the number of GTs, and the more the number, the stronger the activity. However, PGG with five GTs and TA with ten GTs showed almost identical α-glucosidase inhibitory activities, possibly due to the reduced binding force with the enzyme caused by spatial hindrance.

Hypoglycemic effect of Nitraria tangutorum fruit by inhibiting glycosidase and regulating IRS1/PI3K/AKT signalling pathway and its active ingredient identification by UPLC-MS.

The hypoglycemic effect of NTB-40 (40% ethanol fraction of Nitraria tangutorum fruit) in type I/II diabetic mice and its underlying mechanism and active ingredient structure were investigated. The postprandial blood glucose (PBG) lowering effect of NTB-40 treatment was confirmed by maltose, starch, and sucrose tolerance tests in alloxan-induced DM mice and sucrase and maltase inhibitory activities in vitro. More importantly, long-term dosing experiments in high-fat diet-STZ-induced diabetic mice further demonstrated that NTB-40 intervention could improve glycolipid metabolism disorder and insulin resistance (IR) by maintaining glucose homeostasis (FBG, OGTT, ITT, FINS, and HOMA-IR) and lipid homeostasis (TC, TG, HDL-C, LDL-C, and FFA), reducing inflammation (IL-6, IL-1ß, and TNF-α) and oxidative stress (SOD and MDA), ameliorating the liver's histological structural abnormalities, and modulating the IRS1/PI3K/AKT signaling pathway and downstream targets (FOXO1, GSK3ß, GLUT4) for decreasing hepatic gluconeogenesis and promoting glycogen synthesis and glucose uptake. All these results indicated that NTB-40 had an anti-diabetic effect by modulating the IRS1/PI3K/AKT signaling pathway and inhibiting α-glucosidase activity. Finally, the main chemical components of NTB-40, including phenolic acids, flavonoids, and alkaloids, were assigned by UPLC-Triple-TOF MS/MS.

Targeted isolation of cyclooxygenase-2 inhibitors from Saussurea obvallata using affinity ultrafiltration combined with preparative liquid chromatography.

Saussurea obvallata (S. obvallata) is widely used in Qinghai-Tibet Plateau with high medicinal and edible values of reducing inflammation. But, the individual components and mechanisms of action still ill-defined. In this work, an integrated method using affinity ultrafiltration combined with preparative liquid chromatography was developed to identify and separate cyclooxygenase-2 (COX-2) inhibitors from S. obvallata. The sample was pretreated using on-line medium pressure liquid chromatography to yield the active fraction. Then, the potential COX-2 ligands were screened out using affinity ultrafiltration from the targeted fraction and the identified compounds were isolated via preparative liquid chromatography. As a result, four main compounds, coniferin (1), syringin (2), roseoside (3) and grasshopper ketone (4) were targeted isolated with IC50 values of 12.34 ± 1.81, 4.04 ± 0.43, 13.91 ± 2.46 and 7.97 ± 1.21 µM, respectively. Results of this work demonstrated that the developed strategy was effective for the targeted separation of COX-2 inhibitors from natural product extracts.

Rapid screening of α-glucosidase inhibitors in Hypericum perforatum L. using bio-affinity chromatography coupled with UPLC/MS.

α-glucosidase inhibitors (AGIs) are widely used for the treatment of type 2 diabetes, but their side effects have made it to develop novel and alternative AGIs immediately. In this study, the extract of Hypericum perforatum L. (HPE) has been confirmed to have α-glucosidase inhibitory activity in vitro and in vivo. Seven active compounds, rutin, hyperoside, isoquercitrin, avicularin, quercitrin, quercetin, and biapigenin, were screened based on a bio-affinity chromatography column with α-glucosidase enzyme-conjugated solid phase and UPLC/MS, which exhibited excellent α-glycosidase inhibitory effects by the determined IC50 values. The mechanism of α-glycosidase inhibitory activity of biapigenin was studied for the first time. The results showed that biapigenin was a high-potential, reversible, and mixed enzyme inhibitor. Analysis by molecular docking further revealed that hydrophobic interactions were generated by interactions between biapigenin and amino acid residues LYS156, PHE303, PHE314, and LEU313. In addition, hydrogen bonding occurred between biapigenin and α-glucosidase amino acid residues ASP307, SER241, and LYS156. This research identified that biapigenin could be a novel AGI and further applied to the development of potential anti-diabetic drugs. Furthermore, our studies established a rapid in vitro screening method for AGIs from plants.

Two new isoquinoline alkaloids from Hypecoum leptocarpum Hook. f. et Thoms.

Two new isoquinoline alkaloids, hypecocarpinine (1) and leptocaramine (2) along with five known ones including leptopidine (3), corydamine (4), protopine (5), dihydroprotopine (6) and oxohydrastinine (7), were isolated from Hypecoum leptocarpum Hook. f. et Thoms. Structures of the compounds were elucidated using spectroscopic methods, including UV, IR, HR-ESI-MS, 1 D and 2 D NMR. The cytotoxic activities of these compounds were evaluated using MTT assay. The results showed that compounds 2, 4, and 7 have moderate cytotoxicity against human lung cancer (A549) and human gastric carcinoma (MGC-803) cell lines.

The Influence of Growth Mindset on the Mental Health and Life Events of College Students.

Growth mindset refers to our core belief that our talents can be developed through practice, which may influence our thoughts and behaviors. Growth mindset has been studied in a variety of fields, including education, sports, and management. However, few studies have explored whether differences in individuals' growth mindsets influence college students' self-reported mental health. Using the Growth Mindset Scale, Adolescent Self-rating Life Events Checklist, and SCL-90 Scale, data was collected from 2,505 freshmen in a University in China. Findings revealed that the students within the growth mindset group scored significantly lower on "mental health issues" and "stress due to life events" than the students in the fixed mindset group. Our findings suggest that individuals with a growth mindset are less prone to mental health problems than individuals with a fixed mindset.

Hypoglycemic activity of Codonopsis pilosula (Franch.) Nannf. in vitro and in vivo and its chemical composition identification by UPLC-Triple-TOF-MS/MS.

Codonopsis pilosula (Franch.) Nannf. (CPN), mainly planted in the northwest region, is a traditional Chinese medicine/good health food for nourishing qi and promoting blood circulation. This study firstly evaluated the inhibitory effects of the CPN extraction (CPNE) on α-glucosidase in vitro and in vivo, and tentatively confirmed its chemical ingredients by employing UHPLC-Triple-TOF-MS/MS. The CPNE had strong inhibitory activities against mammalian α-glucosidase (sucrase and maltase) and yeast α-glycosidase with semi-inhibitory concentrations (IC50) of 0.241 mg mL-1, 0.326 mg mL-1 and 1.167 mg mL-1, respectively. In addition, the CPNE could significantly decrease the postprandial blood glucose (PBG) levels in the sucrose/maltose/starch tolerance assays of diabetic mice. Furthermore, a total of 29 compounds, including 3 alkaloids, 13 phenolic acids, 8 alcohol glycosides and 5 alkynosides, were assigned based on comparison with the standards and references, as well as the analysis of main fragments. These results demonstrated that CPN could be used as an adjuvant therapy or dietary supplements to effectively control the occurrence and development of diabetes.

Hypoglycemic effects of Rhodiola crenulata (HK. f. et. Thoms) H. Ohba in vitro and in vivo and its ingredient identification by UPLC-triple-TOF/MS.

Rhodiola crenulata (HK. f. et. Thoms) H. Ohba (RC), mainly distributed in the highly cold region of China, has long been used as a medicine/healthy food for eliminating fatigue and increasing blood circulation. This study aimed to evaluate the inhibitory effects of the RCRS extract on α-amylase and α-glucosidase (sucrase and maltase) in vitro and in vivo, and tentatively analyze and identify its chemical ingredients using UPLC-Triple-TOF/MS. The Rhodiola crenulata RCRS extract had strong inhibitory activities against α-amylase, sucrase and maltase with an IC50 of 0.031 mg mL-1, 0.142 mg mL-1 and 0.214 mg mL-1, respectively. Furthermore, the RCRS extract could significantly decrease the postprandial blood glucose (PBG) level of normal mice in a starch tolerance test, and reduce the PBG levels of diabetic mice in a starch/maltose/sucrose tolerance test. UHPLC-Triple-TOF-MS/MS analysis indicated that hydroxybenzoic acids, hydroxycinnamic acids, alcohol glycosides, flavonols and their derivatives were the main active ingredients in the RCRS extract. The results demonstrate that the RCRS extract of Rhodiola crenulata could be employed as a healthy food or medicine for controlling postprandial blood glucose levels.

Identification of α-glucosidase inhibitors from the bran of Chenopodium quinoa Willd. by surface plasmon resonance coupled with ultra-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry.

Extracts from the bran of Chenopodium quinoa Willd. (QBE) were reported to be active in inhibiting α-glycosidase, a promising target for treatment of diabetes mellitus. However, the constituents responsible for the α-glucosidase-inhibiting activity of QBE have not been fully characterized. The present study aimed to set up a method for rapid identification of glycosidase inhibiting compounds from the quinoa bran. With surface plasmon resonance (SPR) coupled with liquid chromatography-mass spectrometry (LC-MS), we identified eight flavonoids and ten triterpenoid saponins that may bind to the α-glycosidase. Analysis of the interaction kinetics by molecular docking supported their α-glucosidase-inhibiting activity and revealed the potential mechanisms for the inhibitory effects. In summary, this study established a SPR and LC-MS-based method for rapid in vitro screening of α-glucosidase inhibitors and suggested the quinoa bran a potential natural source of α-glucosidase inhibitors.

Inhibitory Activity and Mechanism Investigation of Hypericin as a Novel α-Glucosidase Inhibitor.

α-glucosidase is a major enzyme that is involved in starch digestion and type 2 diabetes mellitus. In this study, the inhibition of hypericin by α-glucosidase and its mechanism were firstly investigated using enzyme kinetics analysis, real-time interaction analysis between hypericin and α-glucosidase by surface plasmon resonance (SPR), and molecular docking simulation. The results showed that hypericin was a high potential reversible and competitive α-glucosidase inhibitor, with a maximum half inhibitory concentration (IC50) of 4.66 ± 0.27 mg/L. The binding affinities of hypericin with α-glucosidase were assessed using an SPR detection system, which indicated that these were strong and fast, with balances dissociation constant (KD) values of 6.56 × 10-5 M and exhibited a slow dissociation reaction. Analysis by molecular docking further revealed that hydrophobic forces are generated by interactions between hypericin and amino acid residues Arg-315 and Tyr-316. In addition, hydrogen bonding occurred between hypericin and α-glucosidase amino acid residues Lys-156, Ser-157, Gly-160, Ser-240, His-280, Asp-242, and Asp-307. The structure and micro-environment of α-glucosidase enzymes were altered, which led to a decrease in α-glucosidase activity. This research identified that hypericin, an anthracene ketone compound, could be a novel α-glucosidase inhibitor and further applied to the development of potential anti-diabetic drugs.

Alkaloids and phenolics identification in fruit of Nitraria tangutorum Bobr. by UPLC-Q-TOF-MS/MS and their a-glucosidase inhibitory effects in vivo and in vitro.

Nitraria tangutorum Bobr. (NTB), mainly distributed in the Qaidam Basin of Tibetan Plateau, have high economic, ecological and medicinal value. The chemical compositions in the NTB fruits were tentatively analyzed and characterized by applying UPLC-Q-TOF-MS/MS. Total 45 constituents, including 9 hydroxycinnamic acids derivatives, 12 flavonols, 4 flavonoids, 1 trolox derivative, 8 ß-carboline alkaloids, 4 tryptophan derivatives, and 7 other amino acid derivatives were identified by comparing with standard products, and analyzing their retention times, characteristic fragment ions and deprotonated molecule ions. The activity studies in vitro indicated that NTB-Z and NTB-C extracts had marked inhibitory effects against sucrase and maltase. Further sucrose/maltose/starch tolerance experiment demonstrated that both NTB-Z and NTB-C extracts at 400 mg/kg could markedly lower the postprandial blood glucose (PBG) level in diabetic animals. All these results indicated that the NTB fruits could be used as the functional health food or medicine for controlling postprandial blood glucose level.

Corrigendum: The Relationship Between College Teachers' Frustration Tolerance and Academic Performance.

[This corrects the article DOI: 10.3389/fpsyg.2021.564484.].

Interaction mechanism between location and sequence in letter cognition.

A previous study used days as a sequence symbol to investigate the interaction mechanism between location and sequence in sequence symbol cognition; the study findings suggested that the spatial stimulus-response compatibility effect and the Simon effect could not co-exist with the SNARC-like effect when processing sequence symbols. The previous study did not include the influence of the difficulty of identifying sequence symbols on the Simon effect in the investigation, so it is unclear whether the conclusion about processing sequence symbols with considerable identification difficulty can be extended to the processing of sequence symbols with less identification difficulty. Therefore, the present study explored letters that have a low level of identification difficulty to investigate the interaction mechanism between location and sequence in sequence symbol cognition. Participants were asked to classify a probe letter, which was randomly displayed on the left or right side of the screen, according to its location (Experiment 1), its sequence (Experiment 2) or its colour (Experiment 3). The results indicated that (1) only the spatial stimulus-response compatibility effect and Simon effect were present in the letter location classification task and letter colour classification task, respectively. (2) The Simon effect co-existed with the SNARC-like effect, and these two effects interacted with each other in the letter sequence classification task. From these results, it can be concluded that the task determines whether the Simon effect and the SNARC-like effect can co-exist, with differences presented across sequence symbols.

The Relationship Between College Teachers' Frustration Tolerance and Academic Performance.

The purpose of this study was twofold: to validate the College Teachers' Academic Frustration Tolerance (CTAFT) Questionnaire and the College Teachers' Academic Performance (CTAP) Questionnaire and to explore the relationship between frustration tolerance and academic performance among college teachers. A total of 25 experts were recruited to modify and validate both questionnaires, and the results showed that the questionnaires had good content validity. Exploratory factor analysis provided further evidence supporting the reliability of the CTAFT and the CTAP, suggesting that the instruments are reliable and valid. Confirmatory factor analysis showed that frustration tolerance affected academic performance, which could best be modeled in the three dimensions of Affect (AF), Preferred Difficulties (PD), and Action (AC). A total of 450 college teachers from each faculty of both universities were then recruited to explore the significant positive correlation between academic frustration tolerance and academic performance. The results from the structural equation model suggested that AC and PD combined significantly predicted academic performance. To our knowledge, this is the first study to explore the relationship between college teachers' academic frustration tolerance and academic performance in China.