Tenuifolin improves learning and memory by regulating long-term potentiation and dendritic structure of hippocampal CA1 area in healthy female mice but not male mice

Polygala tenuifolia Wild is an ancient traditional Chinese medicine. Its main component, tenuifolin (TEN), has been proven to improve cognitive impairment caused by neurodegenerative diseases and ovariectomy. However, there was hardly any pharmacological research about TEN and its potential gender differences. Considering the reduction of TEN on learning and memory dysfunction in ovariectomized animals, therefore, we focused on the impact of TEN in different mice genders in the current study. Spontaneous alternation behavior (SAB), light-dark discrimination, and Morris water maze (MWM) tests were used to evaluate the mice's learning and memory abilities. The field excitatory postsynaptic potential (fEPSP) of the hippocampal CA1 region was recorded using an electrophysiological method, and the morphology of the dendritic structure was examined using Golgi staining. In the behavioral experiments, TEN improved the correct rate in female mice in the SAB test, the correct rate in the light-dark discrimination test, and the number of crossing platforms in the MWM test. Additionally, TEN reduced the latency of female mice rather than male mice in light-dark discrimination and MWM tests. Moreover, TEN could significantly increase the slope of fEPSP in hippocampal Schaffer-CA1 and enhance the total length and the number of intersections of dendrites in the hippocampal CA1 area in female mice but not in male mice. Collectively, the results of the current study showed that TEN improved learning and memory by regulating long-term potentiation (LTP) and dendritic structure of hippocampal CA1 area in female mice but not in males. These findings would help to explore the improvement mechanism of TEN on cognition and expand the knowledge of the potential therapeutic value of TEN in the treatment of cognitive impairment.

Stevioside Ameliorates Palmitic Acid-Induced Abnormal Glucose Uptake via the PDK4/AMPK/TBC1D1 Pathway in C2C12 Myotubes

BACKGROUND

Stevioside (SV) with minimal calories is widely used as a natural sweetener in beverages due to its high sweetness and safety. However, the effects of SV on glucose uptake and the pyruvate dehydrogenase kinase isoenzyme (PDK4) as an important protein in the regulation of glucose metabolism, remain largely unexplored. In this study, we used C2C12 skeletal muscle cells that was induced by palmitic acid (PA) to assess the effects and mechanisms of SV on glucose uptake and PDK4.

METHODS

The glucose uptake of C2C12 cells was determined by 2-NBDG; expression of the Pdk4 gene was measured by quantitative real-time PCR; and expression of the proteins PDK4, p-AMPK, TBC1D1 and GLUT4 was assessed by Western blotting.

RESULTS

In PA-induced C2C12 myotubes, SV could significantly promote cellular glucose uptake by decreasing PDK4 levels and increasing p-AMPK and TBC1D1 levels. SV could promote the translocation of GLUT4 from the cytoplasm to the cell membrane in cells. Moreover, in Pdk4-overexpressing C2C12 myotubes, SV decreased the level of PDK4 and increased the levels of p-AMPK and TBC1D1.

CONCLUSION

SV was found to ameliorate PA-induced abnormal glucose uptake via the PDK4/AMPK/TBC1D1 pathway in C2C12 myotubes. Although these results warranted further investigation for validation, they may provide some evidence of SV as a safe natural sweetener for its use in sugar-free beverages to prevent and control T2DM.

Efficient Conversion of Stevioside to Rebaudioside M in Saccharomyces cerevisiae by a Engineering Hydrolase System and Prolonging the Growth Cycle

Rebaudioside (Reb) M is an important sweetener with high sweetness, but its low content in Stevia rebaudiana and low catalytic capacity of the glycosyltransferases in heterologous microorganisms limit its production. In order to improve the catalytic efficiency of the conversion of stevioside to Reb M by Saccharomyces cerevisiae, several key issues must be resolved including knocking out endogenous hydrolases, enhancing glycosylation, and extending the enzyme catalytic process. Herein, endogenous glycosyl hydrolase SCW2 was knocked out in S. cerevisiae. The glycosylation process was enhanced by screening glycosyltransferases, and UGT91D2 from S. rebaudiana was identified as the optimum glycosyltransferase. The UDP-glucose supply was enhanced by overexpressing UGP1, and co-expressing UGT91D2 and UGT76G1 achieved efficient conversion of stevioside to Reb M. In order to extend the catalytic process, the silencing information regulator 2 (SIR2) which can prolong the growth cycle of S. cerevisiae was introduced. Finally, combining these modifications produced 12.5 g/L Reb M and the yield reached 77.9% in a 5 L bioreactor with 10.0 g/L stevioside, the highest titer from steviol glycosides to Reb M reported to date. The engineered strain could facilitate the industrial production of Reb M, and the strategies provide references for the production of steviol glycosides.

Identifying Potential Sources of Phthalate Contamination in the Leaves of Stevia Rebaudiana (Bertoni) and the Development of Removal Technology

Steviosides extracted from the leaves of the plant Stevia rebaudiana are increasingly used in the food industry as natural low-calorie sweeteners. Phthalates in food are often assumed to arise from food containers or packaging materials. Here, experiments were carried out to identify the potential sources of DMP, DBP, DIBP, and DEHP in the leaves of stevioside through investigation of their content in native stevioside tissues, soils, and associated agronomic materials. The results show that phthalate contamination was present in all the samples tested, and the influence of regional factors at the provincial level on the content of plasticizers in stevia leaves was not significant. Phthalates in stevia leaves can be absorbed into the plant body through leaves and roots. Using resin removal, the phthalate content in stevioside glycosides was reduced to less than 0.05 ppm, and some indicators were far lower than the limit standard in EU food.

Prevalence of youth experiencing homelessness and its association with suicidal thoughts and behaviors: Findings from a population-based study

Although various studies have examined factors associated with suicidal behaviors among youth, few studies have investigated the association between youth experiencing homelessness (YEH) and suicidal thoughts and behaviors (STBs) using a large nationally representative sample. The objectives of this study were to investigate prevalence of YEH and its association with STBs. Data for this study came from the 2021 Youth Risk Behavior Survey. An analytic sample of 17,033 youth aged 14-18 (51.7 % male) was analyzed using binary logistic regression. Of the 17,033 youth examined, 3 % experienced homelessness during the past 30 days, 21.3 % experienced suicidal ideation, 17.3 % made a suicide plan, and 10.9 % attempted suicide during the past 12 months. Controlling for demographic characteristics and feeling sad or hopeless, YEH was associated with 2.48 times higher odds of experiencing suicidal ideation (AOR=2.48, p<.001), 2.46 times higher odds of making a suicide plan (AOR=2.46, p<.001), and 4.38 times higher odds of making a suicide attempt (AOR=4.38, p<.001). The findings of this study highlight the importance of identifying youth who are at risk of experiencing homelessness to ensure early interventions are put in place to prevent suicidal behaviors.

Acute and two-week effects of neotame, stevia rebaudioside M and sucrose-sweetened biscuits on postprandial appetite and endocrine response in adults with overweight/obesity-a randomised crossover trial from the SWEET consortium

BACKGROUND

Sweeteners and sweetness enhancers (S&SE) are used to replace energy yielding sugars and maintain sweet taste in a wide range of products, but controversy exists about their effects on appetite and endocrine responses in reduced or no added sugar solid foods. The aim of the current study was to evaluate the acute (1 day) and repeated (two-week daily) ingestive effects of 2 S&SE vs. sucrose formulations of biscuit with fruit filling on appetite and endocrine responses in adults with overweight and obesity.

METHODS

In a randomised crossover trial, 53 healthy adults (33 female, 20 male) with overweight/obesity in England and France consumed biscuits with fruit filling containing 1) sucrose, or reformulated with either 2) Stevia Rebaudioside M (StRebM) or 3) Neotame daily during three, two-week intervention periods with a two-week washout. The primary outcome was composite appetite score defined as [desire to eat + hunger + (100 - fullness) + prospective consumption]/4.

FINDINGS

Each formulation elicited a similar reduction in appetite sensations (3-h postprandial net iAUC). Postprandial insulin (2-h iAUC) was lower after Neotame (95% CI (0.093, 0.166); p < 0.001; d = -0.71) and StRebM (95% CI (0.133, 0.205); p < 0.001; d = -1.01) compared to sucrose, and glucose was lower after StRebM (95% CI (0.023, 0.171); p < 0.05; d = -0.39) but not after Neotame (95% CI (-0.007, 0.145); p = 0.074; d = -0.25) compared to sucrose. There were no differences between S&SE or sucrose formulations on ghrelin, glucagon-like peptide 1 or pancreatic polypeptide iAUCs. No clinically meaningful differences between acute vs. two-weeks of daily consumption were found.

INTERPRETATION

In conclusion, biscuits reformulated to replace sugar using StRebM or Neotame showed no differences in appetite or endocrine responses, acutely or after a two-week exposure, but can reduce postprandial insulin and glucose response in adults with overweight or obesity.

FUNDING

The present study was funded by the Horizon 2020 program: Sweeteners and sweetness enhancers: Impact on health, obesity, safety and sustainability (acronym: SWEET, grant no: 774293).

Comparison of a Daily Steviol Glycoside Beverage compared with a Sucrose Beverage for Four Weeks on Gut Microbiome in Healthy Adults

BACKGROUND

Recent studies suggest that some nonnutritive sweeteners (NNS) have deleterious effects on the human gut microbiome (HGM). The effect of steviol glycosides on the HGM has not been well studied.

OBJECTIVE

We aimed to evaluate the effects of stevia- compared with sucrose-sweetened beverages on the HGM and fecal short-chain fatty acid (SCFA) profiles.

METHODS

Using a randomized, double-blinded, parallel-design study, n = 59 healthy adults [female/male, n = 36/23, aged 31±9 y, body mass index (BMI): 22.6±1.7 kg/m2] consumed 16 oz of a beverage containing either 25% of the acceptable daily intake (ADI) of stevia or 30 g of sucrose daily for 4 weeks followed by a 4-week washout. At weeks 0 (baseline), 4, and 8, the HGM was characterized via shotgun sequencing, fecal SCFA concentrations were measured using ultra-high performance liquid chromatography-tandem mass spectrometry and anthropometric measurements, fasting serum glucose, insulin and lipids, blood pressure, pulse, and 3-d diet records were obtained.

RESULTS

There were no significant differences in the HGM or fecal SCFA between the stevia and sucrose groups at baseline (P > 0.05). At week 4 (after intervention), there were no significant differences in the HGM at the phylum, family, genus, or species level between the stevia and sucrose groups and no significant differences in fecal SCFA. At week 4, BMI had increased by 0.3 kg/m2 (P = 0.013) in sucrose compared with stevia, but all other anthropometric and cardiometabolic measures and food intake did not differ significantly (P > 0.05). At week 8 (after washout), there were no significant differences in the HGM, fecal SFCA, or any anthropometric or cardiometabolic measure between the stevia and sucrose groups (P > 0.05).

CONCLUSIONS

Daily consumption of a beverage sweetened with 25% of the ADI of stevia for 4 weeks had no significant effects on the HGM, fecal SCFA, or fasting cardiometabolic measures, compared with daily consumption of a beverage sweetened with 30 g of sucrose.

TRIAL REGISTRATION

clinicaltrials.gov as NCT05264636.

Ice cream with sucralose, stevioside, and erythritol as sugar substitutes: Sensory profile and customer preference

Sugar-free food has been gaining popularity because of low-calorie content. But sugar replacement by high-intensity sweeteners can negatively affect sensory. In this study, the effect of the addition of sucralose (Suc), stevioside (Ste), and erythritol (Ery) as sugar substitutes on the sensory profile and overall acceptance of ice cream were evaluated by penalty analysis (PA) based on the check-all-that apply (CATA) method, with those of the partial least squares (PLS) regression. Twelve sweetening agents of ice cream samples were presented to 106 consumers who answered on an overall liking question using the 15-point hedonic scale and a CATA question with 32 attributes that described the sensory characteristics of ice cream. The results showed that mixed sweeteners (60%Suc+20%Ste+20%Ery or 60%Suc+10%Ste+30%Ery) can present an advantageous performance when used separately, and making ice cream similar to that of sucrose (Sac) added. Adding Suc, Ste, and Ery to ice cream hardly felt bitterness, astringency, and chemical-like sensations of the sweetening agent. The significant difference between different sweeteners is the intensity and speed of sweetness. Developing combination of high-potency sweeteners that can make sweetness appear quickly could open up new ways to design sugar-free ice cream.

Glaucocalyxin A delays the progression of OA by inhibiting NF-κB and MAPK signaling pathways

BACKGROUND

Osteoarthritis (OA) is a common degenerative joint condition marked by inflammation and cartilage breakdown. Currently, there is a dearth of treatment medications that can clearly slow the course of OA. Glaucocalyxin A (GLA) is a diterpene chemical identified and extracted from Rabdosia japonica with antithrombotic, anticoagulant, anti-tumor, anti-inflammatory, anti-oxidant, and other pharmacological properties. Previous research has linked inflammation to abnormalities in the homeostasis of the extracellular matrix (ECM). Although GLA has been shown to have anti-inflammatory qualities, its effects on the progression of OA are unknown. As a result, the goal of this study was to see if GLA could slow the course of OA.

METHODS

ATDC5 cells were stimulated by IL-1β to create an inflammatory chondrocyte damage model. Quantitative polymerase chain reaction, Western Blot, high-density culture, and immunofluorescence were used to detect the expression levels of associated gene phenotypes. We also created a mouse model of OA induced by destabilization of the medial meniscus (DMM) instability, and GLA was administered intraperitoneally once every two days for eight weeks. Mice knee specimens were stained with hematoxylin-eosin, Safranin O/fast green, and immunohistochemical, and the Osteoarthritis Research Society International grade system and Mankin's score were used to assess the protective effect of GLA on cartilage.

RESULTS

In vitro and in vivo, we explored the effects and molecular processes of GLA as a therapy for OA. The findings demonstrated that GLA might reduce the expression of associated inflammatory mediators and protect the ECM by inhibiting the NF-κB and MAPK signaling pathways. Animal research revealed that GLA could protect against the DMM-induced OA model mice by stabilizing ECM.

CONCLUSION

Taken together, our findings show that GLA has a protective impact on cartilage throughout OA progression, implying that GLA could be employed as a possible therapeutic agent for OA, thus giving a new therapeutic method for the treatment of OA.

Fine-Scale Characterization of Plant Diterpene Glycosides Using Energy-Resolved Untargeted LC-MS/MS Metabolomics Analysis

Plant diterpene glycosides are essential for diverse physiological processes. Comprehensive structural characterization proved to be a challenge due to variations in glycosylation patterns, diverse aglycone structures, and the absence of comprehensive reference databases. In this study, a method for fine-scale characterization was proposed based on energy-resolved (ER) untargeted LC-MS/MS metabolomics analysis using steviol glycosides as a demonstration. Energy-dependent fragmentation patterns were unveiled by a series of model compounds. Distinct glycosylation sites were discerned by leveraging varying fragmentation energies for the precursor ions. The sugar moiety linkage at C19OOH (R1) exhibited facile and intact cleavage at low collision energies, while the sugar moiety at C13-OH (R2) demonstrated consecutive cleavage with increasing energy. Aglycone ions exhibited a higher relative intensity at NCE 50, with relative intensities ranging from 95% to 100%. Subsequently, aglycone candidates, R1 sugar composition, and R2 sugar sequence were deduced through ER-MS/MS analysis. The developed method was applied to Stevia rebaudiana leaves. A total of 91 diterpene glycosides were unambiguously identified, including 16 steviol glycosides with novel acetylglycosylation patterns. This method offers a rapid alternative for glycan analysis and the structural differentiation of isomers. The developed method enhances the understanding of diterpene glycosides in plants, providing a reliable tool for the in-depth characterization of complex metabolite profiles.

Different Anti-inflammatory Drugs on High-Sensitivity C-Reactive Protein in Patients After Percutaneous Coronary Intervention: A Pilot Randomized Clinical Trial

ABSTRACT

Colchicine reduces atherothrombotic cardiovascular events in coronary artery disease because of its anti-inflammatory effect. However, the effects of the other anti-inflammatory drugs in coronary artery disease remain unclear. This study included 132 patients aged 18-80 years who completed the planned percutaneous coronary interventions and were treated with aggressive secondary prevention strategies for 4 weeks. The subjects were randomly assigned to 1 of the following treatment groups for 4 weeks: (1) control: no additional intervention; (2) colchicine: 0.5 mg once a day; (3) tranilast: 0.1 g thrice a day; or (4) oridonin: 0.5 g thrice a day. The primary outcome was the percentage change in high-sensitivity C-reactive protein (hsCRP) levels at the end of 4 weeks. In total, 109 patients completed the study. The mean age was 58.33 years, 81 (74.31%) were male, and 28 (25.69%) were female. The percentage changes in hsCRP after 4 weeks of treatment were -11.62%, -48.28%, -21.60%, and -7.81%, in the control, colchicine, tranilast, and the oridonin groups, respectively. Compared with the control group, only the colchicine group showed significantly greater reduction in hsCRP levels ( P = 0.022). In targeted proteomic analysis, proteins associated with neutrophil activation (azurocidin, myeloperoxidase, and myeloblastin), platelet aggregation (glycoprotein VI), and endothelial damage (galectin-3) were reduced with colchicine therapy. These results show that of 3 anti-inflammatory drugs only colchicine could reduce hsCRP in patients after percutaneous coronary interventions.

Rubusoside As a Multifunctional Stabilizer for Novel Nanocrystal-Based Solid Dispersions with a High Drug Loading: A Case Study

The oral bioavailability of poorly soluble drugs has always been the focus of pharmaceutical researchers. We innovatively combined nanocrystal technology and solid dispersion technology to prepare novel nanocrystalline solid dispersions (NCSDs), which enable both the solidification and redispersion of nanocrystals, offering a promising new pathway for oral delivery of insoluble Chinese medicine ingredients. The rubusoside (Rub) was first used as the multifunctional stabilizer of novel apigenin nanocrystal-based solid dispersions (AP-NSD), improving the in vitro solubilization rate of the insoluble drug apigenin(AP). AP-NSD has been produced using a combination of homogenisation and spray-drying technology. The effects of stabilizer type and concentration on AP nanosuspensions (AP-NS) particles, span, and zeta potential were studied. And the effects of different types of protective agents on the yield and redispersibility of AP-NSD were also studied. Furthermore, AP-NSD was characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). Solubility was used to assess the in vitro dissolution of AP-NSD relative to APIs and amorphous solid dispersions (AP-ASD), and AP-ASD was prepared by the solvent method. The results showed that 20% Rub stabilized AP-NSD exhibited high drug-loading and good redispersibility and stability, and higher in vitro dissolution rate, which may be related to the presence of Rub on surface of drug. Therefore provides a natural and safe option for the development of formulations for insoluble drugs.

Single-Cell Transcriptomics Reveals the Ameliorative Effect of Oridonin on Septic Liver Injury

Sepsis is a life-threatening syndrome leading to hemodynamic instability and potential organ dysfunction. Oridonin, commonly used in Traditional Chinese Medicine (TCM), exhibits significant anti-inflammation activity. To explore the protective mechanisms of oridonin against the pathophysiological changes, the authors conducted single-cell transcriptome (scRNA-seq) analysis on septic liver models induced by cecal ligation and puncture (CLP). They obtained a total of 63,486 cells, distributed across 11 major cell clusters, and concentrated their analysis on four specific clusters (hepatocytes/Heps, macrophages, endothelial/Endos and T/NK) based on their changes in proportion during sepsis and under oridonin treatment. Firstly, biological changes in Hep, which are related to metabolic dysregulation and pro-inflammatory signaling, are observed during sepsis. Secondly, they uncovered the dynamic profiles of macrophage's phenotype, indicating that a substantial number of macrophages exhibited a M1-skewed phenotype associated with pro-inflammatory characteristics in septic model. Thirdly, they detected an upregulation of both inflammatory cytokines and transcriptomic factor Nfkb1 expression within Endo, along with slight capillarization during sepsis. Moreover, excessive accumulation of cytotoxic NK led to an immune imbalance. Though, oridonin ameliorated inflammatory-related responses and improved the liver dysfunction in septic mice. This study provides fundamental evidence of the protective effects of oridonin against sepsis-induced cytokine storm.

The intramolecular SN2 reaction tautomeric ent-Kauranoids isolated from the aerial parts of Isodon amethystoides

As our ongoing searching for the bioactive natural terpenoids, nine ent-kauranoids (1-9), including three previously undescribed ones (1, 2, and 9), were isolated from the aerial parts of Isodon amethystoides. Their structures were elucidated on the basis of spectroscopic data analysis, including NMR, MS, and ECD. Compounds 1 and 2 were a pair of tautomeric compounds, which was confirmed by the HPLC analysis and low temperature NMR testing. The underlying mechanism of the tautomer was proposed as an intramolecular SN2 reaction, which was explained by quantum chemical calculation. The HOMO-LUMO gap and the free energy revealed the spontaneous of the tautomeric of the 1 and 2. Additionally, the similar phenomena were also found in the two groups of known compounds 3 and 4 and 6 and 7, respectively. Apart from the tautomer, compounds 3 and 4 can be hydrolyzed into 5 through ester hydrolysis in CDCl3, while compounds 6, 7 can be hydrolyzed into 8 through ester hydrolysis. These phenomena were also confirmed through HPLC analysis and low temperature nuclear magnetic resonance tests and the mechanism was studied using quantum chemical calculation.

ThermomiR-377-3p-induced suppression of Cirbp expression is required for effective elimination of cancer cells and cancer stem-like cells by hyperthermia

BACKGROUND

In recent years, the development of adjunctive therapeutic hyperthermia for cancer therapy has received considerable attention. However, the mechanisms underlying hyperthermia resistance are still poorly understood. In this study, we investigated the roles of cold‑inducible RNA binding protein (Cirbp) in regulating hyperthermia resistance and underlying mechanisms in nasopharyngeal carcinoma (NPC).

METHODS

CCK-8 assay, colony formation assay, tumor sphere formation assay, qRT-PCR, Western blot were employed to examine the effects of hyperthermia (HT), HT + oridonin(Ori) or HT + radiotherapy (RT) on the proliferation and stemness of NPC cells. RNA sequencing was applied to gain differentially expressed genes upon hyperthermia. Gain-of-function and loss-of-function experiments were used to evaluate the effects of RNAi-mediated Cirbp silencing or Cirbp overexpression on the sensitivity or resistance of NPC cells and cancer stem-like cells to hyperthermia by CCK-8 assay, colony formation assay, tumorsphere formation assay and apoptosis assay, and in subcutaneous xenograft animal model. miRNA transient transfection and luciferase reporter assay were used to demonstrate that Cirbp is a direct target of miR-377-3p. The phosphorylation levels of key members in ATM-Chk2 and ATR-Chk1 pathways were detected by Western blot.

RESULTS

Our results firstly revealed that hyperthermia significantly attenuated the stemness of NPC cells, while combination treatment of hyperthermia and oridonin dramatically increased the killing effect on NPC cells and cancer stem cell (CSC)‑like population. Moreover, hyperthermia substantially improved the sensitivity of radiation‑resistant NPC cells and CSC‑like cells to radiotherapy. Hyperthermia noticeably suppressed Cirbp expression in NPC cells and xenograft tumor tissues. Furthermore, Cirbp inhibition remarkably boosted anti‑tumor‑killing activity of hyperthermia against NPC cells and CSC‑like cells, whereas ectopic expression of Cirbp compromised tumor‑killing effect of hyperthermia on these cells, indicating that Cirbp overexpression induces hyperthermia resistance. ThermomiR-377-3p improved the sensitivity of NPC cells and CSC‑like cells to hyperthermia in vitro by directly suppressing Cirbp expression. More importantly, our results displayed the significantly boosted sensitization of tumor xenografts to hyperthermia by Cirbp silencing in vivo, but ectopic expression of Cirbp almost completely counteracted hyperthermia-mediated tumor cell-killing effect against tumor xenografts in vivo. Mechanistically, Cirbp silencing-induced inhibition of DNA damage repair by inactivating ATM-Chk2 and ATR-Chk1 pathways, decrease in stemness and increase in cell death contributed to hyperthermic sensitization; conversely, Cirbp overexpression-induced promotion of DNA damage repair, increase in stemness and decrease in cell apoptosis contributed to hyperthermia resistance.

CONCLUSION

Taken together, these findings reveal a previously unrecognized role for Cirbp in positively regulating hyperthermia resistance and suggest that thermomiR-377-3p and its target gene Cirbp represent promising targets for therapeutic hyperthermia.

In vitro inhibitory effect of five natural sweeteners on α-glucosidase and α-amylase

A promising and efficacious approach to manage diabetes is inhibiting α-glucosidase and α-amylase activity. Therefore, the inhibitory activities of five natural sweeteners (mogrosides (Mog), stevioside (Ste), glycyrrhizinic acid (GA), crude trilobatin (CT), and crude rubusoside (CR)) against α-glucosidase and α-amylase and their interactions were evaluated in vitro using enzyme kinetics, fluorescence spectroscopy, Fourier infrared spectroscopy, and molecular docking. The inhibitor sequence was CT > GA > Ste, as GA competitively inhibited α-glycosidase activity while CT and Ste exhibited mixed inhibitory effects. Compared to a positive control acarbose, the inhibitory activity of CT was higher. For α-amylase, the mixed inhibitors CT, CR, and Mog and the competitive inhibitor Ste effectively inhibited the enzyme, with the following order: CT > CR > Ste > Mog; nevertheless, the inhibitors were slightly inferior to acarbose. Three-dimensional fluorescence spectra depicted that GA, CT, and CR bound to the hydrophobic cavity of α-glucosidase or α-amylase and changed the polarity of the hydrophobic amino acid-based microenvironment and structure of the polypeptide chain backbone. Infrared spectroscopy revealed that GA, CT, and CR could disrupt the secondary structure of α-glucosidase or α-amylase, which decreased enzyme activity. GA, trilobatin and rubusoside bound to amino acid residues through hydrogen bonds and hydrophobic interactions, changing the conformation of enzyme molecules to decrease the enzymatic activity. Thus, CT, CR and GA exhibit promising inhibitory effects against α-glucosidase and α-amylase.

Oridonin-induced ferroptosis and apoptosis: a dual approach to suppress the growth of osteosarcoma cells

BACKGROUND

Osteosarcoma (OS) is one of the most common aggressive bone malignancy tumors in adolescents. With the application of new chemotherapy regimens, finding new and effective anti-OS drugs to coordinate program implementation is urgent for the patients of OS. Oridonin had been proved to mediate anti-tumor effect on OS cells, but its mechanism has not been fully elucidated.

METHODS

The effects of oridonin on the viability, clonal formation and migration of 143B and U2OS cells were detected by CCK-8, colony formation assays and wound-healing test. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to explore the mechanism of oridonin on OS. Western blot (WB), real-time quantitative PCR (qRT-PCR) were used to detect the expression levels of apoptosis and ferroptosis-relative proteins and genes. Annexin V-FITC apoptosis detection kit and flow cytometry examination were used to detect the level of apoptosis. Iron assay kit was used to evaluate the relative Fe2+ content. The levels of mitochondrial membrane potential and lipid peroxidation production was determined by mitochondrial membrane potential detection kit and ROS assay kit.

RESULTS

Oridonin could effectively inhibit the survival, clonal formation and metastasis of OS cells. The KEGG results indicated that oridonin is associated with the malignant phenotypic signaling pathways of proliferation, migration, and drug resistance in OS. Oridonin was capable of inhibiting expressions of BAX, cl-caspase3, SLC7A11, GPX4 and FTH1 proteins and mRNA, while promoting the expressions of Bcl-2 and ACSL4 in 143B and U2OS cells. Additionally, we found that oridonin could promote the accumulation of reactive oxygen species (ROS) and Fe2+ in OS cells, as well as reduce mitochondrial membrane potential, and these effects could be significantly reversed by the ferroptosis inhibitor ferrostatin-1 (Fer-1).

CONCLUSION

Oridonin can trigger apoptosis and ferroptosis collaboratively in OS cells, making it a promising and effective agent for OS therapy.

Transcriptomic Analyses Reveal Insights into the Shared Regulatory Network of Phenolic Compounds and Steviol Glycosides in Stevia rebaudiana

Stevia rebaudiana (Bertoni) is a highly valuable crop for the steviol glycoside content in its leaves, which are no-calorie sweeteners hundreds of times more potent than sucrose. The presence of health-promoting phenolic compounds, particularly flavonoids, in the leaf of S. rebaudiana adds further nutritional value to this crop. Although all these secondary metabolites are highly desirable in S. rebaudiana leaves, the genes regulating the biosynthesis of phenolic compounds and the shared gene network between the regulation of biosynthesis of steviol glycosides and phenolic compounds still need to be investigated in this species. To identify putative candidate genes involved in the synergistic regulation of steviol glycosides and phenolic compounds, four genotypes with different contents of these compounds were selected for a pairwise comparison RNA-seq analysis, yielding 1136 differentially expressed genes. Genes that highly correlate with both steviol glycosides and phenolic compound accumulation in the four genotypes of S. rebaudiana were identified using the weighted gene co-expression network analysis. The presence of UDP-glycosyltransferases 76G1, 76H1, 85C1, and 91A1, and several genes associated with the phenylpropanoid pathway, including peroxidase, caffeoyl-CoA O-methyltransferase, and malonyl-coenzyme A:anthocyanin 3-O-glucoside-6″-O-malonyltransferase, along with 21 transcription factors like SCL3, WRK11, and MYB111, implied an extensive and synergistic regulatory network involved in enhancing the production of such compounds in S. rebaudiana leaves. In conclusion, this work identified a variety of putative candidate genes involved in the biosynthesis and regulation of particular steviol glycosides and phenolic compounds that will be useful in gene editing strategies for increasing and steering the production of such compounds in S. rebaudiana as well as in other species.

Rebaudioside D decreases adiposity and hepatic lipid accumulation in a mouse model of obesity

Overconsumption of added sugars has been pointed out as a major culprit in the increasing rates of obesity worldwide, contributing to the rising popularity of non-caloric sweeteners. In order to satisfy the growing demand, industrial efforts have been made to purify the sweet-tasting molecules found in the natural sweetener stevia, which are characterized by a sweet taste free of unpleasant aftertaste. Although the use of artificial sweeteners has raised many concerns regarding metabolic health, the impact of purified stevia components on the latter remains poorly studied. The objective of this project was to evaluate the impact of two purified sweet-tasting components of stevia, rebaudioside A and D (RebA and RebD), on the development of obesity, insulin resistance, hepatic health, bile acid profile, and gut microbiota in a mouse model of diet-induced obesity. Male C57BL/6 J mice were fed an obesogenic high-fat/high-sucrose (HFHS) diet and orally treated with 50 mg/kg of RebA, RebD or vehicle (water) for 12 weeks. An additional group of chow-fed mice treated with the vehicle was included as a healthy reference. At weeks 10 and 12, insulin and oral glucose tolerance tests were performed. Liver lipids content was analyzed. Whole-genome shotgun sequencing was performed to profile the gut microbiota. Bile acids were measured in the feces, plasma, and liver. Liver lipid content and gene expression were analyzed. As compared to the HFHS-vehicle treatment group, mice administered RebD showed a reduced weight gain, as evidenced by decreased visceral adipose tissue weight. Liver triglycerides and cholesterol from RebD-treated mice were lower and lipid peroxidation was decreased. Interestingly, administration of RebD was associated with a significant enrichment of Faecalibaculum rodentium in the gut microbiota and an increased secondary bile acid metabolism. Moreover, RebD decreased the level of lipopolysaccharide-binding protein (LBP). Neither RebA nor RebD treatments were found to impact glucose homeostasis. The daily consumption of two stevia components has no detrimental effects on metabolic health. In contrast, RebD treatment was found to reduce adiposity, alleviate hepatic steatosis and lipid peroxidation, and decrease LBP, a marker of metabolic endotoxemia in a mouse model of diet-induced obesity.

Angelica Sinensis Polysaccharide-Based Nanoparticles for Liver-Targeted Delivery of Oridonin

The present work aimed to study the feasibility of Angelica sinensis polysaccharide (ASP) as an instinctive liver targeting drug delivery carrier for oridonin (ORI) in the treatment of hepatocellular carcinoma (HCC). ASP was reacted with deoxycholic acid (DOCA) via an esterification reaction to form an ASP-DOCA conjugate. ORI-loaded ASP-DOCA nanoparticles (ORI/ASP-DOCA NPs) were prepared by the thin-film water method, and their size was about 195 nm in aqueous solution. ORI/ASP-DOCA NPs had a drug loading capacity of up to 9.2%. The release of ORI in ORI/ASP-DOCA NPs was pH-dependent, resulting in rapid decomposition and accelerated drug release at acidic pH. ORI/ASP-DOCA NPs significantly enhanced the accumulation of ORI in liver tumors through ASGPR-mediated endocytosis. In vitro results showed that ORI/ASP-DOCA NPs increased cell uptake and apoptosis in HepG2 cells, and in vivo results showed that ORI/ASP-DOCA NPs caused effective tumor suppression in H22 tumor-bearing mice compared with free ORI. In short, ORI/ASP-DOCA NPs might be a simple, feasible, safe and effective ORI nano-drug delivery system that could be used for the targeted delivery and treatment of liver tumors.

Oridonin loaded peptide nanovesicles alleviate nonalcoholic fatty liver disease in mice

This study was to construct a nanovesicle delivery system to improve the loading efficiency and stability of ORI for the treatment of nonalcoholic fatty liver disease (NAFLD). This nanovesicles (NVs) exerted a narrow size distribution (195.6 ± 11.49 nm) and high entrapment efficiency (84.46 ± 1.34%). In vitro cell studies demonstrated that the NVs treatment enhanced the cellular uptake of ORI and reduced lipid over-accumulation and total cholesterol levels in NAFLD cell model. At the same time, in vivo study proved that, compared with the normal group, the model group mice showed a decrease in body weight, a significant increase in liver index (6.71 ± 0.62, p < 0.01), and symptoms of liver lipid accumulation, lipid vesicles, and liver tissue fibrosis. Compared with the model group, after high-dose ORI NVs intervention, mice gained weight, decreased liver index (4.69 ± 0.55, p < 0.01), reduced hepatic lipid droplet vacuoles, reduced lipid accumulation (reduced oil red area, p < 0.001), and alleviated the degree of liver fibrosis (reduced blue collagen area, p < 0.001). In conclusion, ORI/HP-β-CD/H9-HePC NVs showed specific liver accumulation and improved therapeutic effects, the nano drug loading system provides a promising strategy for the encapsulation of ORI to effectively alleviate the process of NAFLD.

Attenuation of pro-tumorigenic senescent secretory phenotype by StN, a novel derivative of stevioside, potentiates its inhibitory activity on hepatocellular carcinoma

Ent-13-Hydroxy-15-kaurene-19-acid N-Methylpiperazine Ethyl Ester (StN) is a novel derivative of the natural diterpene stevioside isolated from Stevia rebaudiana (Bertoni). In this study, we examined the effects of StN against hepatocellular carcinoma (HCC) in vitro and in vivo as well as its anticancer mechanisms by inhibiting proliferation and regulating the senescence-associated secretory phenotype (SASP). We showed that StN significantly inhibited HCC cell proliferation by inducing cellular senescence, as observed by increased senescence-associated β-galactosidase activity and cell cycle arrest. Mechanistically, StN impaired lysosomal stability and triggered the release of cathepsin B from the lysosomes into the nucleus where it promoted DNA damage. Cathepsin B-mediated DNA damage contributed to cellular senescence triggered by StN. Meanwhile, StN transcriptionally suppressed multiple pro-inflammatory SASP components, including IL-6, IL-1α, IL-1β, and IL-8, resulting in the reduction of pro-tumorigenic impact of SASP. Further study revealed that StN inactivated NF-κB and PI3K/Akt signaling, which significantly accounted for its inhibition on the SASP factors. In HCC xenograft mice, administration of StN significantly suppressed tumor growth, while no significant toxicity was detected. This study demonstrates a novel mechanism that suppressing the SASP by StN in senescent cells potentiates its anticancer efficacy, thus defining a potential compound for cancer treatment.

Chemoproteomics Reveals Glaucocalyxin A Induces Mitochondria-Dependent Apoptosis of Leukemia Cells via Covalently Binding to VDAC1

Chronic myelogenous leukemia (CML) that is resistant to tyrosine kinase inhibitors is one of the deadliest hematologic malignancies, and the T315I mutation in the breakpoint cluster region-Abelson (BCR-ABL) kinase domain is the most prominent point mutation responsible for imatinib resistance in CML. Glaucocalyxin A (GLA), a natural bioactive product derived from the Rabdosia rubescens plant, has strong anticancer activity. In this study, the effect and molecular mechanism of GLA on imatinib-sensitive and imatinib-resistant CML cells harboring T315I mutation via a combined deconvolution strategy of chemoproteomics and label-free proteomics is investigated. The data demonstrated that GLA restrains proliferation and induces mitochondria-dependent apoptosis in both imatinib-sensitive and resistant CML cells. GLA covalently binds to the cysteine residues of mitochondrial voltage-dependent anion channels (VDACs), resulting in mitochondrial damage and overflow of intracellular apoptotic factors, eventually leading to apoptosis. In addition, the combination of GLA with elastin, a mitochondrial channel VDAC2/3 inhibitor, enhances mitochondria-dependent apoptosis in imatinib-sensitive and -resistant CML cells, representing a promising therapeutic approach for leukemia treatment. Taken together, the results show that GLA induces mitochondria-dependent apoptosis via covalently targeting VDACs in CML cells. GLA may thus be a candidate compound for the treatment of leukemia.

Solubility-permeability interplay of a supersaturated lutein delivery system constructed by glycosylated stevioside and hydroxypropyl-methylcellulose

This study investigated the solubilizing capacity of glycosylated stevioside/hydroxypropyl-methylcellulose (stevia-G-HPMC) complexes with varying mass ratios on lutein. The impact on the steady-state flux and permeability coefficient of intracellular lutein was also explored through the construction of a Caco-2 cellular transport model. The results indicated that the equilibrium solubility of lutein linearly increased with an increase in stevia-G amount. The stability constants of the ternary system surpassed those of the binary system. Molecular dynamics simulation revealed a tight and stable structure in lutein supersaturated complexes. Meanwhile, lutein-stevia-G-HPMC complexes demonstrated superior cumulative penetrations, with the peak Papp (AP → BL) value being (3.24 ± 0.89) × 10-5 cm·s-1. There was a slight decrease in Papp (BL → AP), which improved the forward transport of lutein. Highly soluble lutein in aqueous environments saturated the extracellular transport proteins on the AP side of cell membranes, thereby maintaining the high permeability transport. Notably, the permeability trend of lutein in Caco-2 cells negatively correlated with the equilibrium solubility and matched the single exponential growth model. When the mass ratio of lutein, stevia-G and HPMC was 1:21:5, the solubility-permeability trade-off of lutein was effectively maintained.

A sustainable strategy for biosynthesis of Rebaudioside D using a novel glycosyltransferase of Solanum tuberosum

Bioconversion of Rebaudioside D faces high-cost obstacles. Herein, a novel glycosyltransferase StUGT converting Rebaudioside A to Rebaudioside D was screened and characterized, which exhibits stronger affinity and substrate specificity for Rebaudioside A than previously reported enzymes. A whole-cell catalytic system was thus developed using the StUGT strain. The production of Rebaudioside D was enhanced significantly by enhancing cell permeability, and the maximum production of 6.12 g/L and the highest yield of 98.08% by cell catalyst was obtained by statistical-based optimization. A new cascade process utilizing this recombinant strain and E. coli expressing sucrose synthase was further established to reduce cost through replacing expensive UDPG with sucrose. A StUGT-GsSUS1 system exhibited high catalytic capability, and 5.27 g L-1 Rebaudioside D was achieved finally without UDPG addition by systematic optimization. This is the best performance reported in cell-cascaded biosynthesis, which paves a new cost-effective strategy for sustainable synthesis of scarce premium sweeteners from biomass.

Multi-omics analysis of small RNA, transcriptome, and degradome to identify putative miRNAs linked to MeJA regulated and oridonin biosynthesis in Isodon rubescens

Isodon rubescens has garnered much attention due to its anti-tumor or anti-cancer properties. However, little is known about the molecular mechanism of oridonin biosynthesis leveraging the regulatory network between small RNAs and mRNAs. In this study, the regulatory networks of miRNAs and targets were examined by combining mRNA, miRNA, and degradome. A total of 348 miRNAs, including 287 known miRNAs and 61 novel miRNAs, were identified. Among them, 51 miRNAs were significantly expressed, and 36 miRNAs responded to MeJA. A total of 3066 target genes were associated with 228 miRNAs via degradome sequencing. Multi-omics analysis demonstrated that 27 miRNA-mRNA pairs were speculated to be involved in MeJA regulation, and 36 miRNA-mRNA pairs were hypothesized to be involved in the genotype-dependence of I. rubescens. Furthermore, 151 and 7 miRNA-mRNA modules were likely engaged in oridonin biosynthesis as identified by psRNATarget and degradome sequencing, respectively. Some miRNA-mRNA modules were confirmed via RT-qPCR. Moreover, miRNAs targeting plant hormone signal transduction pathway genes were identified, such as miR156, miR167, miR393, and PC-3p-19822_242. Collectively, our results demonstrate for the first time that miRNAs are identified in I. rubescens, and laid a solid foundation for further research on the molecular mechanism of oridonin biosynthesis mediated by miRNA.

Oridonin attenuates apoptosis and NLRP3 inflammasome activation in IL-4-stimulated human bronchial epithelial cells in an in vitro pediatric asthma model

BACKGROUND

Asthma is a chronic illness that causes recurrent inflammation and airway constriction. The primary risk factors for asthma development are exposure to environmental allergens and house dust mites, which can trigger deoxyribonucleic acid (DNA) damage. Oxidative stress can also cause DNA impairments and plays a crucial role in the progression of human immunological disorders.

OBJECTIVES

The aim of the study was to evaluate the effects of oridonin (ORD) on proliferation, inflammation and apoptosis in interleukin 4 (IL-4)-stimulated human bronchial epithelial (16HBE) cells.

MATERIAL AND METHODS

Proliferation was assessed using a 5-Bromo-2-deoxyuridine (BrdU) assay, while acridine orange (AO), ethidium bromide (EB), propidium iodide, and 4',6-diamidino-2-phenylindole (DAPI) measured apoptosis. The protein expression levels of apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), cleaved caspase-1, and nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) were detected with western blot.

RESULTS

The results established that IL-4 stimulation markedly decreased (p < 0.05) the proliferation of 16HBE cells, while the administration of ORD increased their proliferation. Apoptosis and DNA damage were enhanced in the IL-4-stimulated group, whereas ORD exhibited anti-apoptotic activity. Moreover, the treatment with ORD significantly reduced (p < 0.05) the IL-4-induced expression of cleaved caspase-1, ASC and NLRP3 proteins.

CONCLUSIONS

The findings suggest that NLRP3 is a direct target for ORD-mediated anti-inflammatory actions in injured 16HBE cells. Therefore, ORD may be a novel therapy against NLRP3-related disorders, including pediatric asthma (PA).

Biological activity and structural modification of isosteviol over the past 15 years

Isosteviol is a tetracyclic diterpenoid obtained by hydrolysis of stevioside. Due to its unique molecular skeleton and extensive pharmacological activities, isosteviol has attracted more and more attention from researchers. This review summarized the structural modification, pharmacological activity and microbial transformation of isosteviol from 04/2008 to 10/2023. In addition, the research history, structural characterization, and pharmacokinetics of isosteviol were also briefly reviewed. This review aims to provide useful literature resources and inspirations for the exploration of diterpenoid drugs.

Rubusoside mitigates neuroinflammation and cellular apoptosis in Parkinson's disease, and alters gut microbiota and metabolite composition

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative condition characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Neuroinflammation plays a pivotal role in the pathogenesis of PD, involving the activation of microglia cells, heightened production of proinflammatory cytokines, and perturbations in the composition of the gut microbiota. Rubusoside (Ru), the principal steviol bisglucoside present in Rubus chingii var. suavissimus (S.K.Lee) L.T.Lu (Rosaceae), has been documented for its anti-inflammatory properties in diverse disease models. Nonetheless, there is an imperative need to comprehensively assess and elucidate the protective and anti-inflammatory attributes of Ru concerning PD, as well as to uncover the underlying mechanism involved.

OBJECTIVE

The aim of this study is to evaluate the neuroprotective and anti-inflammatory effects of Ru on PD and investigate its potential mechanisms associated with microbes.

RESEARCH DESIGN AND METHODS

We pre-treated mice and cell lines with Ru in order to simulate the progression of PD and the neuroinflammatory state. The mouse model was induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), SN4741 cells were induced by 1-methyl-4-phenylpyridine (mpp+), and BV-2 cells were induced by lipopolysaccharide (LPS). We assessed the impact of Ru on motor function, neuroinflammation, neuron apoptosis, the composition of gut microbes, and their metabolites.

RESULTS

Ru treatment reduces the release of pro-inflammatory mediators by inhibiting microglia activation. It also prevents neuronal apoptosis, thereby safeguarding dopaminergic neurons and ameliorating motor dysfunction. Furthermore, it induces alterations in the fecal microbiota composition and metabolites profile in PD mice. In vitro experiments have demonstrated that Ru inhibits neuronal apoptosis in SN4741 cells induced by mpp+, suppresses the production of pro-inflammatory mediators, and activates the c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase (p38 MAPK), and nuclear factor kappa-B (NF-κB) signaling pathways.

CONCLUSION

Ru exhibits inhibitory effects on the MPTP-induced PD model by mitigating neuroinflammation and neuronal apoptosis while also inducing changes in the gut microbiota and metabolite composition.

A partial peroxisome proliferator-activated receptor gamma agonist isolated from the roots of Euphorbia sikkimensis

Chemical constituents of the Euphorbia sikkimensis roots was investigated and twelve known compounds were isolated, including three ent-atisane diterpenes: ent-(13S)-hydroxyatis-16-ene-3,14-dione (1), ent-(5β,8α,9β,10α,11α,12α)-11-hydroxyatis-16-ene-3,14-dione (2), ent-atisane-3-oxo-16α,17-diol (3); two kaurene diterpenes: ent-kaurane-3-oxo-16α,17-diol (4), ent-kaurane-3-oxo-16β,17-diol (5); one lathyane diterpene of latilagascene B (6); two flavonoids: quercetin (7), luteolin (8); one lignin d-pinoresinol (9); one coumarin scopoletin (10); together with ethyl gallate (11), p-hydroxybenzaldehyde (12). Their structures were identified based on the extensive spectroscopic analysis in comparison with the literature data. Compounds 1, 2, 4, 6 and 9 were isolated from Euphorbia sikkimensis for the first time. The agonistic activity of peroxisome proliferator-activated receptor gamma (PPARγ) for compounds 1, 7, 8, 9 and 11 was evaluated. Compound 1 exhibited moderate agonistic activity for PPARγ receptor with relative fluorescence intensity of 10.19 at 30.0 µM, in comparison with that of the positive control of rosiglitazone (28.50 at 2.0 µM).

The persistent impact of the COVID-19 pandemic on pediatric emergency department visits for suicidal thoughts and behaviors

INTRODUCTION

We examined data from a large, high acuity, pediatric psychiatric emergency department (ED) to assess both the immediate and longer-term impact of the pandemic on ED visits for suicidal thoughts and behaviors (STBs) among youth.

METHODS

Youth ages 5-17 years presenting at a pediatric psychiatric ED in New York, NY from March 2019-November 2021 were included in this study. Visits were categorized as pre-pandemic, pandemic year 1, or pandemic year 2. We examined changes in demographic and clinical characteristics among patients presenting across the three time periods, as well as multivariable associations between these characteristics and STBs.

RESULTS

Over 32 months, 2728 patients presented at 4161 visits. The prevalence of a discharge diagnosis of STBs increased from 21.2% pre-pandemic to 26.3% (p < 0.001) during pandemic year 1, and further increased to 30.1% (p = 0.049) during pandemic year 2. Youth were 21% more likely to receive a discharge diagnosis of STBs in pandemic year 1 (RR 1.21, 95% CI 1.07, 1.36) and 35% more likely in pandemic year 2 (RR 1.35, 95% CI 1.19, 1.52) compared to pre-pandemic baseline.

CONCLUSIONS

In a large, high-acuity ED, STBs continued to increase 20 months after the initial COVID-19 lockdown. These findings highlight the persistent detrimental impact of the pandemic on youth mental health.

Oridonin inhibited epithelial-mesenchymal transition of laryngeal carcinoma by positively regulating LKB1/AMPK signaling

Oridonin is the main bioactive component of Rabdosia rubescens, and its anticancer activity has been reported in a variety of cancers. However, the molecular mechanism of oridonin in laryngeal carcinoma remains unclear. In the present study, the cytotoxic effect of oridonin on laryngeal carcinoma Hep-2 and TU212 cell lines were initially detected by modified MTT assay. The results showed that oridonin had a dose-dependent anti-proliferative effect on laryngeal carcinoma Hep-2 and TU212 cells. Next, we found that oridonin significantly inhibited the migration and invasion of human laryngeal carcinoma Hep-2 and TU212 cell lines by wound healing assay and transwell assay. Subsequently, the results of quantitative real-time PCR assay and western blotting assay confirmed that oridonin upregulated the expression of E-cadherin while downregulated the expression of N-cadherin in a concentration-dependent manner at mRNA and protein levels. In addition, phosphorylation levels of liver kinase B1 (p-LKB1) and AMP-activated protein kinase (p-AMPK) were also elevated upon oridonin treatment. To further verify the role of LKB1/AMPK signaling pathway in laryngeal carcinoma, overexpression of LKB1 was constructed by plasmid transfection. The data exhibited that overexpression of LKB1 could further reinforce the increase of E-cadherin level and decrease of N-cadherin level mediated by oridonin. Additionally, AMPK inhibitor compound C could reverse anti-metastatic effect of oridonin on laryngeal carcinoma, and antagonise EMT expression. In contrast, AMPK activator AICAR presented the opposite effect. In conclusion, our study revealed that oridonin could remarkably reverse the epithelial-mesenchymal transition of laryngeal carcinoma by positively regulating LKB1/AMPK signaling pathway, which suggested that oridonin may be a potential candidate for the treatment of laryngeal carcinoma in the future.

F16 Hybrids Derived from Steviol or Isosteviol Are Accumulated in the Mitochondria of Tumor Cells and Overcome Drug Resistance

Steviol and isosteviol were prepared from the commercially available sweetener stevioside and converted into lipophilic F16 hybrids. Their cytotoxicity was determined in SRB assays and showed to depend on both the substitution pattern of the aromatic substituent as well as on the spacer length. Therefore, compound 25 held an IC50 (A2780) of 180 nM, thus surpassing the activity of comparable rhodamine hybrids. Several of the compounds were also able to overcome drug resistance in the A2780/A2780cis model. Extra staining experiments showed a similar subcellular accumulation pattern of the F16 hybrids as a well-established mitocan, hence proving preferential mitochondrial accumulation but also some other accumulation in other cellular areas.

Production of Gibberellins via a Non-Natural Pathway Using Steviol as a Substrate

Gibberellins (GAs) are plant hormones widely used in agriculture. At present, GAs are produced by fermentation of the fungus Fusarium fujikuroi. However, fungal growth is too slow, resulting in slow fungal fermentation and a low yield. Here, to develop an alternative production source of GAs, an artificial pathway was engineered in Escherichia coli. By selecting and combining enzymes derived from plants and bacteria, a novel 4-enzyme pathway was successfully constructed to produce GAs using steviol, a readily available and less valuable byproduct during enzymatic refining of rebaudioside A, as a feedstock. Whole-cell biotransformation with E. coli strain expressing the novel pathway produced 71.17 ± 2.00 mg/L GA1 and a trace amount of GA3 from steviol in 48 h. This report presents a significant advancement in the fast production of GAs and establishes a method for the metabolism of terpenoids to produce target products in microbial hosts.

Anti-inflammatory activities of several diterpenoids isolated from Hemionitis albofusca

Hemionitis albofusca (Baker) Christenh is a plant that grows in various regions of China. Although it is not recognized as a traditional medicine, it is often mistakenly labelled and used as Aleuritopteris argentea (S. G. Gmél.) Fée to alleviate menstruation-related issues. Recently, several diterpenoids such as ent-16-oxo-17-norkauran-19-oic acid (Compound A), 14-oxy-7β,20-dihydroxycyath-12,18-diene (Compound B), ent-8(14),15-pimaradiene-2β,19-diol (Compound C), ent-kaurane-16-ene-2β,18α-diol (Compound D), ent-kaurane-2β,16α,18α-triol (Compound E), and onychiol B have been extracted from H. albofusca. In this study, we investigated the anti-inflammatory activity of these diterpenes. We confirmed that compounds A ~ D suppressed the amount of cellular NO production by inhibiting the expression and transcription of iNOS protein. They also significantly inhibited the expression and transcription of inflammatory factors TNF-α and IL-6. Additionally, Compounds A and C suppressed the activation of the NF-κB signaling pathway and inhibited the phosphorylation level of p38, ultimately down-regulating inflammation. Compound B suppressed the activation of the NF-κB signaling pathway, while Compound D inhibited the phosphorylation level of p38 and down-regulated the activation of the p38 MAPK signaling pathway. In a word, our investigation supports the potential application of natural diterpenes as lead compounds for developing anti-inflammatory agents.

Impact of rebaudioside A degradation compounds on flavor perception

Rebaudioside A, a sweet-tasting steviol glycoside, is known to degrade in food products during storage and thought to contribute to flavor instability. The impact of rebaudioside A degradation compounds on flavor perception was investigated. Sensory descriptive analysis indicated rebaudioside A degradation compounds, at concentrations below detection thresholds, modified the perception of taste, somatosensorial, and retronasal aroma attributes of a strawberry-flavored model beverage. Gas chromatography/mass spectrometry analysis and orthonasal sensory tetrad tests further indicated the addition of the degradation compounds did not significantly alter the volatile aroma composition or orthonasal perception, respectively. Altogether, subthreshold unimodal and cross-modal integration of multisensory percepts were supported to impact the flavor performance of rebaudioside A.

Laxiflorin B covalently binds the tubulin colchicine-binding site to inhibit triple negative breast cancer proliferation and induce apoptosis

Laxiflorin B is a natural ent-kaurane diterpenoid that can be isolated from the leaves of the Isodon eriocalyx var. laxiflora, a perennial shrub native to parts of China. While this compound has potent cytotoxic activity against various tumor cells, the anti-tumor targets and molecular mechanisms of Laxiflorin B are unclear. Here, we show that Laxiflorin B exhibits strong antiproliferative and proapoptotic effects on triple-negative breast cancer (TNBC) cells. At the mechanistic level, we show that β-tubulin (TUBB) is a cellular target of Laxiflorin B. By covalently binding the Cys239 and C354 residues of the TUBB colchicine-binding site, Laxiflorin B disturbs microtubule integrity and structure in vitro and in vivo. Cytotoxicity analyses also showed that the α, β-unsaturated carbonyl in the D ring of Laxiflorin B is responsible for mediating its covalent binding and anti-tumor activity. To assess the therapeutic effects of Laxiflorin B, we synthesized a Laxiflorin B-ALA pro-drug and delivered it by intraperitoneal injection (10 mg/kg) into a 4T1 orthotopic tumor mouse model. Drug treatment had anti-tumor effects without inducing notable weight loss or organ dysfunction. We conclude that Laxiflorin B is a promising colchicine binding site inhibitor that might be exploited in the context of TNBC treatment in the future.

Unreported ent-rosane diterpenes from Croton niveus Jacq. (Euphorbiaceae). Cytotoxic activity and docking studies

From the bioactive extract of the euphorbiaceous Croton niveus Jacq., three previously unreported ent-rosane diterpenes have been isolated and characterized by conventional methods, in addition to the known compounds lupeol, cajucarinolide and some phytosterols. Two of the ent-rosane diterpenes displayed activity against HCT-15 and PC-3 cancer cell lines, and the results of docking calculations of these compounds with NF-κB and STAT3 receptors agreed with the proposed mode of action of diterpenes against PC-3 cells.

A chromosome-level genome assembly reveals that tandem-duplicated CYP706V oxidase genes control oridonin biosynthesis in the shoot apex of Isodon rubescens

The ent-kaurenoids (e.g., oridonin and enmein) from the Isodon genus (Lamiaceae) are one class of diterpenoids with rich structural diversity and intriguing pharmaceutical activity. In contrast to the well-established gibberellin pathway, oxidative modifications diversifying the ent-kaurene skeleton in Isodon have remained undetermined for half a century. Here we report a chromosome-level genome assembly of I. rubescens, a well-recognized oridonin producer long favored by Asian people as a traditional herb with antitumor effects. The shoot apex was confirmed to be the actual region actively producing ent-kaurene diterpenoids. Through comparative genomics and phylogenetic analyses, we discovered a cluster of tandem-duplicated CYP706V oxygenase-encoding genes located on an ancient genomic block widely distributed in eudicots, whereas almost exclusively emerged in Isodon plants. In the shoot apex, IrCYP706V2 and IrCYP706V7 oxidized the ent-kaurene core in the initial stage of oridonin biosynthesis. Loss of CYP706Vs in other Lamiaceae plants offered an explanation for the specific kaurenoid production in Isodon plants. Moreover, we found that the Isodon genomes encode multiple diterpenoid synthases that are potentially involved in generating diterpenoid diversity. These findings provided new insights into the evolution of the lineage-specific diterpenoid pathway and laid a foundation for improving production of bioactive ent-kaurene-type diterpenoids by molecular breeding and synthetic biology approaches.

Enhancement of diterpenoid steviol glycosides by co-overexpressing SrKO and SrUGT76G1 genes in Stevia rebaudiana Bertoni

Stevia rebaudiana (stevia) contains commercially important steviol glycosides, stevioside and rebaudioside A, these compounds have insulinotropic and anti-hyperglycemic effect. Steviol, stevioside and rebaudioside-A have taste modulation and insulin potentiation activity. Stevia leaves are composed of steviol (2-5%), stevioside (4-13%) and rebaudioside-A (1-6%). Stevioside has after-taste bitterness, rebaudioside-A is sweetest in taste among all the glycosides present. Therefore, lower ratio of rebaudioside-A to stevioside has bitter after-taste, which makes stevia plants unpalatable. By over-expressing the genes, SrUGT76G1 and SrKO, we propose to increase the ratio of RebA to stevioside in stevia. Various lines were generated and amongst them, seven lines had both the transgenes present. Co-overxpresion of SrUGT76G1 and SrKO led to the increased concentration of RebA in all the seven transgenic lines (KU1-KU7) than control plant and RebA to stevioside ratio also increased significantly. Steviol, stevioside and RebA showed a differential concentration in all the seven lines, but the pattern was the same in all of them and the ratio of RebA to stevioside increased dramatically. In transgenic line 2 (KU2), RebA showed a steep increase in concentration 52% the rebaudioside-A to stevioside ratio increased from 0.74 (control) to 2.83. In overall all the lines, RebA showed a positive correlation with steviol and stevioside. Overexpression of SrKO led to an increase in steviol which increased the stevioside, overexpression of SrUGT76G1 ultimately increased RebA concentration. In conclusion, concentration of RebA increased significantly with co- overexpression of SrUGT6G1 and SrKO genes. Lines with increased RebA are more palatable and commercially viable.

Phytochemical and pharmacological review of diterpenoids from the genus Euphorbia Linn (2012-2021)

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia is one of the major genera in angiosperms, which is widely distributed all over the world, including Asia, Africa and Central and South America. The roots or tubers of Euphorbia are famous for medicinal purposes, especially in China. Many of them, such as Euphorbia pekinensis Rupr, Euphorbia fischeriana Steud and Euphorbia Kansui S.L.Liou ex S.B.Ho. . are used as Chinese herbal medicines.

AIM OF THE STUDY

This paper reviews the diterpenoids isolated from the genus Euphorbia species and the pharmacological activities of these compounds to evaluate its traditional use and potential future development.

MATERIALS AND METHODS

Information on the studies of the genus Euphorbia Linn was collected from scientific journals, books and reports via library and electronic data search (Scifinder, Web of Science, PubMed, Elsevier, Scopus, Google Scholar, Springer, Science Direct, Wiley, ACS, CNKI and Kew Plants of the Word Online). Meanwhile, it was also obtained from published works of material medica, folk records, ethnophmacological literatures, Ph.D. and Masters dissertations.

RESULTS

Known as the main constituents of the genus Euphorbia Linn, Diterpenoids possess many pharmacological properties such as anti-inflammation, antiviral activities and cytotoxicity. To date, various types of diterpenoids were identified from this genus, including isopimarane, rosane, abietane, ent-kaurane, ent-atisane. cembrane, casbane, lathyrane, myrsinane, jatropholane, tigliane, ingenane, jatrophane, paraliane, pepluane, and euphoractin.

CONCLUSIONS

This review describes 14 types of diterpenoid isolated from 45 Euphorbia species from 2012 to 2021, a total of 615 compounds. Among them, mainly include jatrophane (171), lathyrane (92), myrsinane (62), abietane (70), ent-atisane (36), ent-kaurane (7), tigliane (26) and ingenane (19). The possible biological pathways of these compounds were presumed. At the same time, more than 10 biological activities of these compounds were summarized, such as anti-inflammation, antiviral activities and cytotoxicity.

Oridonin relieves depressive-like behaviors by inhibiting neuroinflammation and autophagy impairment in rats subjected to chronic unpredictable mild stress

Major depressive disorder (MDD) is a severe life-threatening disorder with increasing prevalence. However, the mechanistic interplay between depression, neuroinflammation, and autophagy is yet to be demonstrated. This study investigated the effect of Oridonin on CUMS-induced depression, neuroinflammation, and autophagy impairment. Male 4-week-old Sprague-Dawley rats were subjected to chronic unpredictable mild stress (CUMS), some of which were injected with Oridonin, fluoxetine (FLX), or their combination at different durations of CUMS. CUMS significantly increased the levels of cytokines (IL-1β, IL-18, and caspase-1), reduced autophagy-related protein levels (Beclin-1, p62, Atg5, and LC3B), and caused microglia cells activation. Oridonin prevented and reversed the depressive-like behavior. Furthermore, it has a stronger and longer-lasting antidepressant effect than FLX. And the antidepressant effect of Oridonin in combination with fluoxetine was greater than that of high-dose fluoxetine alone. In addition, Oridonin significantly normalized autophagy-related protein levels, and reduced levels of cytokines by blocking the interaction between NLRP3 and NEK7. Similarly, Oridonin abolished levels of cytokines and reversed autophagy impairment in LPS-activated BV2 cells. All these results supported our hypothesis that Oridonin possesses potent anti-depressive action, which might be mediated via inhibition of neuroinflammation and autophagy impairment by blocking the interaction between NLRP3 and NEK7.

Oridonin attenuates hind limb ischemia-reperfusion injury by modulating Nrf2-mediated oxidative stress and NLRP3-mediated inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Oridonin (Ori), extracted from Isodon rubescens (Hemsl.) H.Hara, is a well-known traditional Chinese herbal medicinal product that possesses antioxidant and anti-inflammatory activities. Oxidative stress and inflammation are the main pathophysiological mechanisms in hindlimb IR injury. However, whether Ori has a protective effect on hind limb IR injury is unknown.

AIM OF THE STUDY

The present study was designed to determine the effect of Ori on hindlimb IR injury and its relationship with oxidative stress and inflammation.

MATERIALS AND METHODS

The hind limb IR injury model in mice was used to evaluate the protective effect and related mechanisms of Ori. Forty-eight C57BL/6 mice (n = 12 per group) were randomly divided into four groups: Sham group; IR group; IR + Ori (10 mg/kg) group and IR + Ori (20 mg/kg) group. Mice in the IR and IR + Ori groups were subjected to hindlimb IR injury, while mice in the Sham group were subjected to no hindlimb IR injury. HE staining, Masson's staining, TTC staining, DHE staining, TUNEL staining, western blotting analysis and quantitative real-time PCR were employed to explore the mechanisms by which Ori exerts a protective effect on a classical hindlimb IR model in mice.

RESULTS

We found that Ori pretreatment prevented muscle damage and decreased cell apoptosis levels compared with the vehicle control. Moreover, the SOD2, CAT, MDA and ROS levels in muscle showed that Ori could significantly reduce oxidative stress in hindlimb IR mice, while the IL-1β and TNF-α levels in muscle showed that Ori could significantly attenuate IR-induced inflammation. We also found that Ori could increase the expression of Nrf2 and its downstream protein HO-1 and inhibit the expression levels of NLRP3-related proteins (NLRP3, ASC and Caspase-1) in vivo.

CONCLUSIONS

Our study suggested that Ori has a protective effect on hindlimb IR injury, which may be related to Nrf2-mediated oxidative stress and NLRP3-mediated inflammasome activation.

Discovery of oridonin as a novel agonist for BRS-3

BACKGROUND

Bombesin Receptor Subtype-3 (BRS-3, Bombesin-like receptor, BB₃) is an orphan G-protein coupled receptor (GPCR). Recent studies have shown that BRS-3 played a vital role in glucose regulation, insulin secretion, and energy homeostasis. Therefore, discovering more novel exogenous ligands with diverse structures for BRS-3 will be of great importance for target validation and drug development.

PURPOSE

In this study, we aim to discover new agonists of BRS-3 from our natural compound libraries, providing a new probe to study the function of BRS-3.

STUDY DESIGN

Multiple cell-based assays and in vivo experiments were performed to identify the new ligand.

METHODS

BRS-3 overexpression cells were coupled with FLIPR assay, homogeneous time-resolved fluorescence (HTRF) IP-ONE assay, dynamic mass redistribution (DMR) assay, β-arrestin2 recruitment assay, and western blot to determine receptor activation and downstream signaling events. To further validate the target of BRS-3, a series of in vitro and in vivo experiences were conducted, including glucose uptake, glucose transporter type 4 (GLUT4) transportation in C2C12, and oral glucose tolerance test (OGTT) in mice.

RESULTS

We discovered and identified oridonin as a novel small molecule agonist of BRS-3, with a moderate affinity (EC₅₀ of 2.236 × 10^-7 M in calcium mobilization assay), specificity, and subtype selectivity. Further in vitro and in vivo tests demonstrated that oridonin exerted beneficial effects in glucose homeostasis through activating BRS-3.

CONCLUSIONS

Oridonin, as the discovered new ligand of BRS-3, provides a valuable tool compound to investigate BRS-3's function, especially for target validation in type 2 diabetes and obesity. Oridonin is promising as a lead compound in the treatment of metabolic disorders. Compared to the known agonists of BRS-3, we can take advantage of the multiple reported pharmacological activities of ODN as a natural product and assess whether these pharmacological activities are regulated by BRS-3. This may facilitate the discovery of novel functions of BRS-3.

Enhancement of Rebaudioside M Production by Structure-Guided Engineering of Glycosyltransferase UGT76G1

Owing to zero-calorie and advanced organoleptic properties similar to sucrose, the plant-derived rebaudioside M (Reb M) has been considered as a next generation sweetener. However, a low content of Reb M in Stevia rebaudiana Bertoni and low enzymatic activity of UGT76G1, which is an uridine diphosphate glucose (UDPG)-dependent glycosyltransferase with the ability to glycosylate rebaudioside D (Reb D) to produce Reb M through the formation of β-1,3 glycosidic bond, restrict its commercial usage. To improve the catalytic activity of UGT76G1, a variant UGT76G1-T284S/M88L/L200A was obtained by structure-guided evolution, whose catalytic activity toward Reb D increased by 2.38 times compared with UGT76G1-T284S. This allowed us to prepare Reb M on a large-scale with a great yield of 90.50%. Moreover, molecular dynamics simulation illustrated that UGT76G1-T284S/M88L/L200A reduced distances from Reb D to catalytic residues and UDPG. Hence, we report an efficient method for the potential scale production of Reb M in this study.

Study on physicochemical characteristics of lutein nanoemulsions stabilized by chickpea protein isolate-stevioside complex

BACKGROUND

Chickpea protein isolate (CPI) originating from chickpeas has the advantages of facilitating the stability of food emulsions. Stevioside (STE) exhibits a notable surface activity and can improve the water solubility of numerous hydrophobic nutrients. STE and protein mixtures show great potential as emulsions stabilizers. The present study aimed to prepare a novel nanoemulsion for encapsulating lutein (LUT) by ultrasonic homogenization using chickpea protein isolate-stevioside complex (CPI-STE) as a stabilizer and also to investigate the physicochemical characteristics.

RESULTS

The results obtained showed that different preparation conditions demonstrated significant influences on the physicochemical properties of CPI-STE-LUT nanoemulsions. Under the optimal condition, the average particle size of CPI-STE-LUT nanoemulsions was 195.1 nm, and the emulsifying and encapsulation efficiencies of lutein were 91.04% and 87.56%, respectively. CPI-STE-LUT nanoemulsions stabilized by CPI-STE could significantly increase the emulsifying and encapsulation efficiencies of lutein compared to that stabilized by CPI. Fourier transform infrared spectroscopy revealed that hydrogen bond was the main binding force of CPI and lutein, and there was a covalent bond between the two molecules. Furthermore, the stability of CPI-STE-LUT nanoemulsions in gastrointestinal phase was higher than that of CPI-LUT nanoemulsions, which could load lutein more effectively and be more resistant to digestive enzymes.

CONCLUSION

The present study reports the physicochemical characterization of CPI-STE-LUT nanoemulsions for the first time. CPI-STE-LUT nanoemulsions were characterized by a small average particle size lower than 200 nm, as well as high emulsifying and encapsulation efficiencies, and good stability. © 2021 Society of Chemical Industry.

Effect of light intensity on steviol glycosides production in leaves of Stevia rebaudiana plants

Stevia rebaudiana leaf extracts contain stevioside and rebaudioside A, two steviol glycosides (SGs) used as natural sweeteners because of their non-toxic, thermally stable and non-caloric properties. Indeed, leaf extracts can be up to 300 times sweeter than sucrose. Stevioside and rebaudioside A have organoleptic differences, the first one having an undesirable bitterness and the second one a higher sweetener capacity. Selection of the S. rebaudiana varieties and the best environmental conditions that elicit higher SGs content and the appropriate composition is an important goal. In this study we quantified and compared the amount of stevioside and rebaudioside A in two of the most used S. rebaudiana cultivars, Morita II and Criolla. Our results show a strong differential ratio of stevioside and rebaudioside A accumulated in the leaf between these cultivars. The Criolla cultivar showed about 3 times more stevioside per mg of dry weight than Morita II, whereas the Morita II accumulated almost 10 times more rebaudioside A than that produced in Criolla. We observed an enhanced expression in Morita II of three genes (SrKA13H, SrUGT74G1 and SrUGT76G1) known to encode three enzymes that participate in SGs biosynthesis, likely contributing to the differences in the stevioside and rebaudioside A accumulation. Not only genetic variation can affect SGs composition, but also environmental factors and crop management. Numerous studies have shown that the light regime in which S. rebaudiana cultivars grow can affect SGs accumulation. However, the optimal light regime to increase total SGs content is currently controversial. By applying various light intensities, we detected an increase of expression of these three biosynthetic genes at higher light intensity, accompanied by higher levels of stevioside and rebaudioside A, demonstrating that light intensity influences the synthesis of SGs.

Unusual ent-Kaurane Diterpenes from the Coffea Cultivar S288 Coffee Beans and Molecular Docking to α-Glucosidase

A total of 11 new (1-11) and 2 known (12 and 13) ent-kaurane diterpene derivatives were identified from the roasted beans of Coffea cultivar S288. Their structures were established by extensive spectroscopic analysis, including one- and two-dimensional nuclear magnetic resonance (heteronuclear single-quantum correlation, heteronuclear multiple-bond correlation, correlation spectroscopy, and rotating-frame Overhauser enhancement spectroscopy), high-resolution electrospray ionization mass spectrometry, and X-ray analyses. Cafespirone acid A (1) represents the first example of diterpene featuring a spirocyclic skeleton constructed from a 6/6/5 tricyclic system. Cafeane acid A (2) possesses a 6/6/6/5 tetracyclic system as a result of the C/D ring rearrangement. Furthermore, compounds 1-12 were evaluated for their α-glucosidase inhibitory activity. The results showed that compounds 2, 4, 5, 6, 7, 10, and 11 had a moderate inhibitory effect on α-glucosidase, and half-maximal inhibitory concentration values of compounds 4, 6, 7, and 10 were 18.76 ± 1.46, 4.88 ± 0.03, 12.35 ± 0.91, and 12.64 ± 0.59 μM, respectively, compared to the positive control acarbose (60.71 ± 16.45 μM). Additionally, the molecular docking experiments showed that the carbonyl group at C-19 of compounds 4, 6, and 7 formed strong hydrogen bonds with ARG315, which may make them have moderate inhibitory activity.

[Diterpenoids from Rabdosia flexicaulis]

The genus Rabdosia is famous for the abundance of diverse and novel ent-kaurane diterpenoids. However, only a few ent-kauranoids have been discovered from R. flexicaulis since the investigation on its chemical constituents is not systematic. To find novel bioactive diterpenoids, the ethyl acetate extract of the above ground part of R. flexicaulis in Daofu County, Sichuan Province was obtained by column chromatography. One new compound and five known ones were identified as flexicaulin E(1), forrestin B(2), inf-lexarabdonin D(3), 7α-hydroxydehydroabietic acid(4), 15-hydroxydehydroabietic acid(5), and pomiferin F(6) by spectral techniques. Compounds 1-3 were the ent-kaurane diterpenoids isolated from this species for the first time. Compounds 4-6, aromatic abie-tanoids, were isolated from the genus Rabdosia for the first time.

Preparation of Tenuifolin from Polygala senega L. Root Using a Hydrolytic Continuous Flow System under High-Temperature, High-Pressure Conditions

An improved process for preparing tenuifolin (presenegenin 3-β-d-glucopyranoside) from the root of Polygala senega L. was developed. A crude saponin mixture extracted from P. senega was subjected to hydrolysis, and the reactivity of compounds in the extract was controlled by utilizing the combination of a flow reactor and experimental design. In addition, column chromatography with HP 20, a synthetic polystyrenic adsorbent, allowed the gram-scale preparation of tenuifolin in a continuous manner with fewer steps. This approach shortens the total time required for gram-scale preparation from 16 to 5 h in a continuous manner while improving the yield from 0.59% to 2.08% (w/w).