Release of acetylcholine by syringin, an active principle of Eleutherococcus senticosus, to raise insulin secretion in Wistar rats

Syringin: a naturally occurring compound with medicinal properties

Syringin, a phenylpropanoid glycoside, is widely distributed in various plants, such as Acanthopanax senticosus (Rupr. et Maxim.) Harms, Syringa reticulata (BL) Hara var. mandshurica (Maxim.) Hara, and Ilex rotunda Thumb. It serves as the main ingredient in numerous listed medicines, health products, and foods with immunomodulatory, anti-tumor, antihyperglycemic, and antihyperlipidemic effects. This review aims to systematically summarize syringin, including its physicochemical properties, plant sources, extraction and separation methods, total synthesis approaches, pharmacological activities, drug safety profiles, and preparations and applications. It will also cover the pharmacokinetics of syringin, followed by suggestions for future application prospects. The information on syringin was obtained from internationally recognized scientific databases through the Internet (PubMed, CNKI, Google Scholar, Baidu Scholar, Web of Science, Medline Plus, ACS Elsevier, and Flora of China) and libraries. Syringin, extraction and separation, pharmacological activities, preparations and applications, and pharmacokinetics were chosen as the keywords. According to statistics, syringin can be found in 23 families more than 60 genera, and over 100 species of plants. As a key component in many Chinese herbal medicines, syringin holds significant research value due to its unique sinapyl alcohol structure. Its diverse pharmacological effects include immunomodulatory activity, tumor suppression, hypoglycemic action, and hypolipidemic effects. Additionally, it has been shown to provide neuroprotection, liver protection, radiation protection, cardioprotection, and bone protection. Related preparations such as Aidi injection, compound cantharidin capsule, and Tanreqing injection have been widely used in clinical settings. Other studies on syringin such as extraction and isolation, total synthesis, safety profile assessment, and pharmacokinetics have also made progress. It is crucial for medical research to deeply explore its mechanism of action, especially regarding immunity and tumor therapy. Meanwhile, more robust support is needed to improve the utilization of plant resources and to develop extraction means adapted to the needs of industrial biochemistry to further promote economic development while protecting people's health.

Hepatoprotective effect of syringin combined with costunolide against LPS-induced acute liver injury in L-02 cells via Rac1/AKT/NF-κB signaling pathway

Acute liver injury (ALI) leads to abnormal liver function and damage to liver cells. Syringin (syr) and costunolide (cos) are the major extracts from Dolomiaea souliei (Franch.) C.Shih (D. souliei), showing diverse biological functions in various biological processes. We explored the underlying hepatoprotective effects of syr+cos against LPS-induced ALI. Cell viability and proliferation were assessed using an MTT assay and immunofluorescence staining. Flow cytometry analysis was used to detect cell cycle distribution and apoptosis. ELISA was utilized to measure liver function and antioxidant stress indexes. qRT-PCR and western blotting was performed to determine mRNA and protein levels respectively. Using shRNA approach to Rac1 analyzed transcriptional targets. The results showed that syr+cos promoted L-02 cell proliferation, inhibiting the cell apoptosis and blocking cell cycle in G1 and G2/M phase. Syr+cos decreased the production of ALT, AST, LDH, MDA and ROS while increased SOD and CAT activities. Pretreated with syr+cos may decrease expressions of caspase-3,7,9, NF-κB, TNF-α proteins, Cyclin B, CDK1 and p-IκB proteins while p-IκB increased. Silencing of Rac-1 may protect the liver by increasing AKT, S473, T308 and reducing p-AKT proteins. Syr+cos exhibits anti-ALI activity via Rac1/AKT/NF-κB signaling pathway which might act as an effective candidate drug for the treatment of ALI.

Syringin exerts anti-inflammatory and antioxidant effects by regulating SIRT1 signaling in rat and cell models of acute myocardial infarction

INTRODUCTION

This study aimed to investigate the role of syringin in improving heart function during myocardial ischemia/reperfusion (I/R) and to determine whether the sirtuin 1/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (SIRT1/PGC-1α) pathway contributes to this cardioprotective effect in vivo and in vitro.

METHODS

H9c2 cells were incubated with H₂ O₂ for 12 h. The effect of syringin was assessed by measuring cell viability; the apoptotic rate; Keap1/NRF2/HO-1 activation; and the levels of proinflammatory cytokines, oxidative products, and antioxidative enzymes. In addition, SIRT1 was silenced via short hairpin RNA (shRNA)-SIRT1 transfection to evaluate its involvement in syringin-mediated protection. Syringin rescued cells from H₂ O₂ -induced reductions in viability, antioxidative enzyme levels, and NRF2/HO-1 activation; likewise, syringin inhibited apoptosis, inflammation, and oxidative stress. We also created a rat model of I/R by ligating the left anterior descending coronary artery for 30 min, followed by reperfusion for 12 min. Syringin was then intraperitoneally injected, and the effect on infarct size and cardiac function was examined after 7 days. NRF2/HO-1 activity and the levels of myocardial proinflammatory cytokines, oxidative products, and antioxidative enzymes were measured.

RESULTS

In comparison to the untreated I/R group, the syringin treatment group exhibited improved cardiac function and reduced cardiac lesion and infarct size. Syringin administration also markedly reduced the levels of proinflammatory cytokines and reactive oxygen species and promoted antioxidative enzyme expression and NRF2/HO-1 pathway activation.

CONCLUSIONS

Syringin may serve a protective role in animal and cell models of I/R by improving cardiac function, inhibiting the inflammatory response, and activating the antioxidative response.

A systematic review: Botany, phytochemistry, traditional uses, pharmacology, toxicology, quality control and pharmacokinetics of Ilex rotunda Thunb

ETHNOPHARMACOLOGICAL RELEVANCE

Ilex rotunda Thunb. (I. rotunda) is an Ilex species of Aquifoliaceae, widely distributed in East Asia. Its dried bark is commonly used as a medicinal part in the field of traditional Chinese medicine (TCM), named Ilicis Rotundae Cortex. This medicinal plant is commonly used for clearing heat and removing toxin, draining dampness and relieving pain in TCM to treat tonsillitis, acute gastroenteritis, gastric and duodenal ulcer, rheumatism, traumatic injury, and so on. It also has significant development value on lipid-lowering, hepatoprotection and anti-inflammation, but the potential mechanism needs to be further explored.

AIM OF THE REVIEW

More and more medicinal substances are being discovered in I. rotunda with multiple biological activities, which help to advance the ethno-pharmacological research in I. rotunda. However, to date there is a lack of a systematic summary of research progress on I. rotunda. This review aims to provide a critical summary of the current studies on I. rotunda. The progress in research on botany, phytochemistry, traditional uses, pharmacology, toxicology, quality control and pharmacokinetics of the plant is discussed. It hopes to provide useful references and guidance for the future directions of research on I. rotunda.

MATERIALS AND METHODS

Studies of I. rotunda were collected via Google Scholar and Baidu Scholar, PubMed, ScienceDirect, SciFinder, Web of Science, China National Knowledge Infrastructure (CNKI), WANFANG DATA and libraries. Some local books, official websites, PhD or MS's dissertations were also included. The literature cited in this review covered the period from 1956 to January 2022.

RESULTS

Analysis of the literature indicates that I. rotunda is a potentially valuable herbal medicine for the therapeutic of various diseases. To date, 120 compounds were found and identified in I. rotunda, mainly including triterpenoids, phenylpropanoids, etc. Modern pharmacological studies also found that the plant has the activities of protecting the cardiovascular system, lowering lipids and protecting the liver, as well as being an anti-inflammatory, anti-tumor and antibacterial.

CONCLUSIONS

This review summarizes the results from current studies of I. rotunda. However, the current explanation seems insufficient and unsatisfactory, in terms of the relationships between the traditional uses and the modern pharmacological activities, the mechanisms and the material basis. Thus, a critical and comprehensive evaluation is necessary to explore its future research prospects and development direction.

Integrated network pharmacology and hepatic metabolomics to reveal the mechanism of Acanthopanax senticosus against major depressive disorder

Objective:Acanthopanax senticosus (Rupr. et Maxim.) Harms (ASH) is a traditional herbal medicine widely known for its antifatigue and antistress effects, as well as tonifying qi, invigorating spleen and kidney, and tranquilizing the mind. Recent evidence suggests that ASH has a therapeutic effect on major depressive disorder (MDD), but its mechanism is still unclear. The current study aimed to investigate the effect of ASH on MDD and potential therapeutic mechanisms.

Materials and Methods: The chemical compound potential target network was predicted based on network pharmacology. Simultaneously, chronic unpredictable mild stress (CUMS) model mice were orally administrated ASH with three dosages (400, 200, and 100 mg/kg) for 6 weeks, and hepatic metabolomics based on gas chromatography–mass spectrometry (GC–MS) was carried out to identify differential metabolites and related metabolic pathways. Next, the integrated analysis of metabolomics and network pharmacology was applied to find the key target. Finally, molecular docking technology was employed to define the combination of the key target and the corresponding compounds.

Results: A total of 13 metabolites and four related metabolic pathways were found in metabolomics analysis. From the combined analysis of network pharmacology and metabolomics, six targets (DAO, MAOA, MAOB, GAA, HK1, and PYGM) are the overlapping targets and two metabolic pathways (glycine, serine, and threonine metabolism and starch and sucrose metabolism) are the most related pathways. Finally, DAO, MAOA, MAOB, GAA, HK1, and PYGM were verified bounding well to their corresponding compounds including isofraxidin, eleutheroside B1, eleutheroside C, quercetin, kaempferol, and acacetin.

Conclusion: Based on these results, it was implied that the potential mechanism of ASH on MDD was related to the regulation of metabolism of several excitatory amino acids and carbohydrates, as well as the expression of DAO, MAOA, MAOB, GAA, HK1, and PYGM.

Pharmacology of α-spinasterol, a phytosterol with nutraceutical values: A review

α-Spinasterol is a phytosterol found in various edible and non-edible plant sources. The edible plant materials containing α-spinasterol include spinach leaves, cucumber fruits, seeds of pumpkin and watermelon, argan seed oil, cactus pear seed oil and Amaranthus sp. It is a bioavailable nutraceutical, and it can cross the blood-brain barrier. It possesses several important pharmacological properties such as anti-diabetes mellitus, antiinflammation, hypolipidemic, antiulcer, neuroprotection, anti-pain and antitumour activities. For this review, literature search was made focusing on the pharmacological properties of α-spinasterol using PubMed and Google Scholar data bases. Recent studies show the promising antidiabetic properties of α-spinasterol. Its anti-diabetic mechanisms include enhancement of insulin secretion, reduction in insulin resistance, anti-diabetic nephropathy, increase in glucose uptake in muscle cells and inhibition of glucose absorption from intestine. Besides, it is a safe antiinflammatory agent, and its antiinflammatory mechanisms include inhibition of cyclooxygenases, antagonism of TRPV1 receptor and attenuation of proinflammatory cytokines and mediators. It is a promising and safe nutraceutical molecule for human health care. Food supplements, value-added products and nutraceutical formulations can be developed with α-spinasterol for the management of diabetes, chronic inflammatory diseases and improving general health. This review provides all scattered pharmacological studies on α-spinasterol in one place and highlights its immense value for human health care.

The Therapeutic Effect of Acanthopanax senticosus Components on Radiation-Induced Brain Injury Based on the Pharmacokinetics and Neurotransmitters

Acanthopanax senticosus (AS) is a medicinal and food homologous plant with many biological activities. In this research, we generated a brain injury model by 60Co -γ ray radiation at 4 Gy, and gavaged adult mice with the extract with AS, Acanthopanax senticocus polysaccharides (ASPS), flavones, syringin and eleutheroside E (EE) to explore the therapeutic effect and metabolic characteristics of AS on the brain injury. Behavioral tests and pathological experiments showed that the AS prevented the irradiated mice from learning and memory ability impairment and protected the neurons of irradiated mice. Meanwhile, the functional components of AS increased the antioxidant activity of irradiated mice. Furthermore, we found the changes of neurotransmitters, especially in the EE and syringin groups. Finally, distribution and pharmacokinetic analysis of AS showed that the functional components, especially EE, could exert their therapeutic effects in brain of irradiated mice. This lays a theoretical foundation for the further research on the treatment of radiation-induced brain injury by AS.

Eleutheroside B, a selective late sodium current inhibitor, suppresses atrial fibrillation induced by sea anemone toxin II in rabbit hearts

Eleutheroside B (EB) is the main active constituent derived from the Chinese herb Acanthopanax senticosus (AS) that has been reported to possess cardioprotective effects. In this study we investigated the effects of EB on cardiac electrophysiology and its suppression on atrial fibrillation (AF). Whole-cell recording was conducted in isolated rabbit atrial myocytes. The intracellular calcium ([Ca²⁺]_i) concentration was measured using calcium indicator Fura-2/AM fluorescence. Monophasic action potential (MAP) and electrocardiogram (ECG) synchronous recordings were conducted in Langendorff-perfused rabbit hearts using ECG signal sampling and analysis system. We showed that EB dose-dependently inhibited late sodium current (I_NaL), transient sodium current (I_NaT), and sea anemone toxin II (ATX II)-increased I_NaL with IC₅₀ values of 167, 1582, and 181 μM, respectively. On the other hand, EB (800 μM) did not affect L-type calcium current (I_CaL), inward rectifier potassium channel current (I_K), and action potential duration (APD). Furthermore, EB (300 μM) markedly decreased ATX II-prolonged the APD at 90% repolarization (APD₉₀) and eliminated ATX II-induced early afterdepolarizations (EADs), delayed afterdepolarizations (DADs), and triggered activities (TAs). Moreover, EB (200 μM) significantly suppressed ATX II-induced Na⁺-dependent [Ca²⁺]_i overload in atrial myocytes. In the Langendorff-perfused rabbit hearts, application of EB (200 μM) or TTX (2 μM) substantially decreased ATX II-induced incidences of atrial fibrillation (AF), ventricular fibrillation (VF), and heart death. These results suggest that augmented I_NaL alone is sufficient to induce AF, and EB exerts anti-AF actions mainly via blocking I_NaL, which put forward the basis of pharmacology for new clinical application of EB.

Acanthopanax senticosus Harms extract causes G0/G1 cell cycle arrest and autophagy via inhibition of Rubicon in human liver cancer cells

Acanthopanax senticosus (Rupr. et Maxim) Harms (ASH), also known as Siberian ginseng or eleuthero, is a hardy shrub native to China, Korea, Russia and the northern region of Japan. ASH is used for the treatment of several diseases such as heart disease, hypertension, rheumatoid arthritis, allergies, chronic bronchitis, diabetes and cancer. In the present study, the inhibitory effect of the root extract of ASH (ASHE) on HuH-7 and HepG2 liver cancer cells was examined. ASHE suppressed liver cancer cell proliferation by inducing cell cycle arrest at the G0/G1 phase, as well as apoptosis, as indicated by the increased number of Annexin V and 7-AAD-positive cells. Furthermore, the expression of LC3-II, an autophagy marker, in these cells also increased post treatment with ASHE. LC3-II induction was further enhanced by co-treatment with chloroquine. Fluorescence and transmission electron micrographs of ASHE-treated liver cancer cells showed the presence of an increased number of autophagic vesicles. A decreased protein expression level of run domain Beclin-1-interacting and cysteine-rich domain-containing, an autophagy inhibitor, with no change in RUBCN mRNA expression was observed, indicating activation of the autophagosome-lysosome fusion step of autophagy. In conclusion, ASHE exerts cytostatic activity on liver cancer cells via both apoptosis and autophagy, and may serve as a potential therapeutic agent for management of liver cancer and autophagy-related diseases.

Targeted Development-Dependent Metabolomics Profiling of Bioactive Compounds in Acanthopanax senticosus by UPLC-ESI-MS

An ultra-performance liquid chromatography-electrospray ionization-mass spectrometry targeted metabolomics strategy was applied to analyze protocatechuate, syringin, eleutheroside E, isofraxidin, hyperoside, kaempferol, and oleanolic acid, the active compounds in 3-year-old, 5-year-old, and 9-year-old Acanthopanax senticosus. Then, targeted metabolomics was conducted with 3 growth year plants to identify 19 phenolic metabolites related to the above-mentioned active compounds, including 9 C6C3C6-type, 6 C6C3-type, and 4 C6C1-type. Multivariate statistical analysis was applied to the bioactive metabolite data, and targeted metabolic profiling was used for marker compound classification and characterization. The results showed that 7 active compounds in the roots and stems in the 3 growth year plants differed. The principal component “Q” values showed that the total contents of 7 active compounds in 5-year-old roots and stems were higher than in other growth years. Results of targeted metabolomics profiling of 19 phenolic metabolites showed that the C6C1-type compounds accumulated in 9-year-old plants, the C6C3-type in 3-year-old plants, and the C6C3C6-type in 5-year-old plants. The stems had the greatest accumulations of the phenolic metabolites. C6C1 and C6C3-type metabolites are the most abundant in both roots and stems. In conclusion, the active compounds and pharmacological effects of A. senticosus in different growth years are different. The best harvest age for A. senticosus roots and stems was 5 years. The accumulation of 19 phenolic metabolites in different growth years also showed significant differences.

Comparative metabolomics unveils molecular changes and metabolic networks of syringin against hepatitis B mice by untargeted mass spectrometry

Untargeted metabolomics technology was used to discover the metabolic pathways and biomarkers for revealing the potential biological mechanism of syringin on hepatitis B virus. Serum samples were analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)-based comparative metabolomics coupled with pattern recognition methods and network pathway. In addition, the histopathology, HBV DNA detection of liver tissue, and biochemical indicators of liver function change were also explored for investigating the antiviral effect of syringin. In comparison to the model group, the metabolic profiles of the turbulence in transgenic mice tended to recover to the same as the control group after syringin therapy. A total of 33 potential biomarkers were determined to explore the metabolic disorders in the hepatitis B animal model, of which 25 were regulated by syringin, and 8 metabolic pathways, such as phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, arachidonic acid metabolism, glyoxylate and dicarboxylate metabolism, were involved. Syringin markedly reduced the liver pathology change, inhibited HBV DNA replication, and improved liver function. Amino acid metabolism is a potential target for the treatment of hepatitis B. The hepatoprotective effect of syringin may contribute to ameliorating oxidative stress and preventing protein and DNA replication. Comparative metabolomics is a promising tool for discovering metabolic pathways and biomarkers of the hepatitis B animal model as targets to reveal the effects and mechanism of syringin, which benefits the development of natural products and advances the treatment of diseases.

Untargeted metabolomics technology was used to discover the metabolic pathways and biomarkers for revealing the potential biological mechanism of syringin on hepatitis B virus.

A review on the immunomodulatory activity of Acanthopanax senticosus and its active components

Acanthopanacis Senticosi Radix et Rhizoma seu Caulis, the dried root and rhizome or stem of Acanthopanax senticosus, is commonly known as Siberian ginseng or Ciwujia in Chinese. It is used all over the world as an adaptogen to enhance physical and mental performance for the sake of normal physiological functioning of human bodies under stress. In the theory of traditional Chinese medicine, Ciwujia can strengthen the spleen that is an essential organ for immunological response. Its traditional applications include inflammation, fatigue and cancer in which the immune-regulating function is always involved. In this article, the immunomodulatory activities of Ciwujia extracts, fractions and pure compounds were extensively reviewed first. Then, the possibility of upgrading the chemical markers to bioactive markers was explored. Finally, the potency of aqueous extract and ethanol extract in regulating cytokines production from human peripheral blood mononuclear cells was compared. We conclude that although various phytochemicals such as isofraxidin, syringin and eleutheroside E from Ciwujia have been shown to modulate immunological functions, the aqueous extract of Ciwujia as a whole possesses the most potent efficacy. Therefore, aqueous (rather than ethanol) extract of Ciwujia should be used in order to benefit from its immunomodulatory properties.

Effects of Eleutherococcus Extract Mixture on Endochondral Bone Formation in Rats

Eleutherococcus extract mixture (EEM) is an herbal mixture of dried stem of Eleutherococcus sessiliflorus and germinated barley, which has been highly effective, in previous screening and among the traditional medicines to tonify innate qi and acquired qi, respectively. In this study, we investigate the effects of EEM on endochondral bone formation. Female adolescent rats were given EEM, growth hormone or vehicle for 10 days. Tetracycline was intraperitoneally injected to light the fluorescent band 72 h before sacrifice to determine endochondral bone formation. In order to evaluate endocrine or paracrine/autocrine mechanisms, expressions of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3), or bone morphogenetic protein 2 (BMP2) were evaluated after EEM administration in liver or growth plate (GP). EEM oral administration significantly increased endochondral bone formation and proliferative and hypertrophic zonal heights of tibial GP. EEM also upregulated hepatic IGF1 and IGFBP3 mRNA expressions, and IGF1 and BMP2 expressions in GP. Taken together, EEM increases endochondral bone formation through stimulating proliferation and hypertrophy with upregulation of hepatic IGF1 and IGFBP3 expressions. Considering immunohistochemical studies, the effect of EEM may be due to increased local IGF1 and BMP2 expression in GP, which may be considered growth hormone (GH)-dependent endocrine and autocrine/paracrine pathways.

Optimization of Vacuum Microwave-Mediated Extraction of Syringoside and Oleuropein from Twigs of Syringa oblata

A vacuum microwave-mediated method was used to extract syringoside and oleuropein from Syringa oblata twigs. The optimal extraction conditions were an ethanol volume fraction of 40%, a liquid-solid ratio of 17 mL/g, 1 h of soaking time, -0.08 MPa of vacuum, a microwave irradiation power of 524 W, and a microwave irradiation time of 8 min. Under optimal parameters, the maximum yields of syringoside (5.92 ± 0.24 mg/g) and oleuropein (4.02 ± 0.18 mg/g) were obtained. The proposed method is more efficient than conventional methods for extracting syringoside and oleuropein from Syringa oblata. Moreover, less energy and time were required. The results implied that vacuum microwave-mediated extraction is a suitable method for the extraction of thermosensitive glycosides such as syringoside and oleuropein.

Syringin attenuates insulin resistance via adiponectin-mediated suppression of low-grade chronic inflammation and ER stress in high-fat diet-fed mice

In the treatment of type 2 diabetes, improvements in glucose control are often linked to side effects such as weight gain and altered lipid metabolism, increasing the risk of cardiovascular disease. It is therefore important to develop antidiabetic drugs that exert beneficial effects on insulin sensitivity and lipid metabolism at the same time. Here we demonstrate that syringin, a naturally occurring glucoside, improves glucose tolerance without increased weight gain in high-fat diet-induced obese mice. Syringin augmented insulin-stimulated Akt phosphorylation in skeletal muscle, epididymal adipose tissue (EAT), and the liver, showing an insulin-sensitizing activity. Syringin-treated mice also showed markedly elevated adiponectin production in EAT and suppressed expression of pro-inflammatory cytokines in peripheral tissues, indicating a significant reduction in low-grade chronic inflammation. Additionally, syringin enhanced AMP-activated protein kinase activity and decreased the expression of lipogenic genes in skeletal muscle, which was associated with reduced endoplasmic reticulum (ER) stress. Taken together, our data suggest that syringin attenuates HFD-induced insulin resistance through the suppressive effect of adiponectin on low-grade inflammation, lipotoxicity, and ER stress, and show syringin as a potential therapeutic agent for prevention and treatment of type 2 diabetes with low risk of adverse effects such as weight gain and dysregulated lipid metabolism.

Chemical Prospection of Important Ayurvedic Plant Tinospora cordifolia by UPLC-DAD-ESI-QTOF-MS/MS and NMR

A rapid, sensitive, and accurate ultra-performance liquid chromatography coupled with mass spectrometric method (UPLC-MS) was developed and validated for simultaneous determination of four bioactive compounds, syringin (3), cordifolioside A (4), magnoflorine (6) and tinocordiside (10) in the stem of Tinospora cordifolia. The analysis was performed using an Acquity C18 column and gradient elution of 0.05% formic acid in water and acetonitrile at a detection wavelength of 267 nm in 5 min. A high correlation coefficient (r2 > 0.998) indicated good correlation between investigated compounds concentration and their peak area within the test ranges. The LODs for compounds 3, 4, 6 and 10 were 1.95, 0.97, 3.90 and 0.97 ng/mL, respectively, and LOQs were 6.64, 3.20, 12.87 and 3.20 ng/mL, respectively. The overall intra- and inter-day variations of the four compounds were less than 1%. The variation of these four bioactive compounds in T. cordifolia hosted on fifteen different trees was also determined. The compounds (3, 4, 6 and 10) were found in high amount in the T. cordifolia hosted on Azadirachta indica and Mangifera indica as compared with other plants. Twelve compounds were identified on the basis of their mass and UV-vis spectra. The NMR fingerprinting of the extract revealed the presence of alkaloids, fatty acid methyl esters, polysaccharides and marker components of T. cordifolia.

Phytochemical profile of Paulownia tomentosa (Thunb). Steud

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

Evaluation of the antioxidant activity and antiproliferative effect of the jaboticaba (Myrciaria cauliflora) seed extracts in oral carcinoma cells

It is becoming increasingly evident that certain phytochemicals possess cancer chemopreventive properties. In this study, the antiproliferative activity of extracts from different parts of the jaboticaba (Myrciaria cauliflora) plant was evaluated for its effect on human oral carcinoma cell lines. The cytotoxicities of various plant extract concentrations were examined and the 50% maximal inhibitory concentration (IC₅₀) was determined. Water extracts of jaboticaba seeds showed concentration-dependent antiproliferative effects. Annexin V/propidium iodide positivity with active caspase-3 induction indicated that the treated cells underwent apoptosis. Several important regulatory proteins (Bcl-2, Bcl-xL, Bid, and survivin) involved in apoptosis were also evaluated. The antioxidant activity of jaboticaba was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays, and the drug concentration eliciting 50% maximum stimulation (SC₅₀) was determined. The present findings suggest that water extracts of jaboticaba seeds exhibit an antiproliferative effect against oral cancer cells by inducing apoptosis through downregulating survivin expression and thereby activating caspase-mediated Bid cleavage.

Enzymatic and metabolic engineering for efficient production of syringin, sinapyl alcohol 4-O-glucoside, in Arabidopsis thaliana

To promote efficient production of syringin, a plant-derived bioactive monolignol glucoside, synergistic effects of enzymatic and metabolic engineering were combined. Recombinant UGT72E3/E2 chimeras, generated by exchanging parts of the C-terminal domain including the Putative Secondary Plant Glycosyltransferase (PSPG) motif of UGT72E3 and UGT72E2, were expressed in leaves of transgenic Arabidopsis plants; syringin production was measured in vivo and by enzymatic assays in vitro. In both tests, UGT72E3/2 displayed substrate specificity for sinapyl alcohol like the parental enzyme UGT72E3, and the syringin production was significantly increased compared to UGT72E3. In particular, in the in vitro assay, which was performed in the presence of a high concentration of sinapyl alcohol, the production of syringin by UGT72E3/2 was 4-fold higher than by UGT72E3. Furthermore, to enhance metabolic flow through the phenylpropanoid pathway and maintain a high basal concentration of sinapyl alcohol in the leaves, UGT72E3/2 was combined with the sinapyl alcohol synthesis pathway gene F5H encoding ferulate 5-hydroxylase and the lignin biosynthesis transcriptional activator MYB58. The resulting UGT72E3/2+F5H+MYB58 OE plants, which simultaneously overexpress these three genes, accumulated a 56-fold higher level of syringin in their leaves than wild-type plants.

Identification of adiponectin receptor agonist utilizing a fluorescence polarization based high throughput assay

Adiponectin, the adipose-derived hormone, plays an important role in the suppression of metabolic disorders that can result in type 2 diabetes, obesity, and atherosclerosis. It has been shown that up-regulation of adiponectin or adiponectin receptor has a number of therapeutic benefits. Given that it is hard to convert the full size adiponectin protein into a viable drug, adiponectin receptor agonists could be designed or identified using high-throughput screening. Here, we report on the development of a two-step screening process to identify adiponectin agonists. First step, we developed a high throughput screening assay based on fluorescence polarization to identify adiponectin ligands. The fluorescence polarization assay reported here could be adapted to screening against larger small molecular compound libraries. A natural product library containing 10,000 compounds was screened and 9 hits were selected for validation. These compounds have been taken for the second-step in vitro tests to confirm their agonistic activity. The most active adiponectin receptor 1 agonists are matairesinol, arctiin, (-)-arctigenin and gramine. The most active adiponectin receptor 2 agonists are parthenolide, taxifoliol, deoxyschizandrin, and syringin. These compounds may be useful drug candidates for hypoadiponectin related diseases.

Intermittent hyperglycemia due to autonomic nervous system dysfunction: a new feature in patients with congenital central hypoventilation syndrome

OBJECTIVE

To analyze glycemic profile in children with congenital central hypoventilation syndrome, which is characterized by autonomic nervous system dysfunction.

STUDY DESIGN

We carried out a university hospital-based observational study. Participants included 14 patients assessed from 2007 to 2009 with a median age of 7.6 (25th-75th percentiles, 1.5-9.6) years at the time of the study. Glucose metabolism was assessed by calculating 24-hour plasma glucose (before and after meals) and fasting insulin concentrations and carrying out an oral glucose tolerance test (OGTT). The main outcome measure was the proportion of patients with abnormal glucose concentrations.

RESULTS

Abnormal plasma glucose concentrations were found in 6 (43%) of the 14 patients with high fasting (n = 1) or postprandial (n = 5) hyperglycemia. OGTT was performed in 8 patients, of whom 3 (38%) had impaired glucose tolerance. Indices of insulin resistance and secretion were normal. No difference in clinical aspects relating to the presence of affected organs and/or systems related to central nervous system dysfunction, age, or auxology findings was found between patients with normal (43%) and abnormal (57%) glucose homeostasis over a 24-hour glycemia cycle or OGTT.

CONCLUSION

This study provides new information about glucose homeostasis in congenital central hypoventilation syndrome, revealing a high incidence of hyperglycemia and expanding the spectrum of the disease. It highlights the link between autonomic nervous system dysfunction and glycemic dysregulation. Regular, long-term monitoring of glucose metabolism is recommended in these patients.

Enrichment and purification of syringin, eleutheroside E and isofraxidin from Acanthopanax senticosus by macroporous resin

In order to screen a suitable resin for the preparative simultaneous separation and purification of syringin, eleutheroside E and isofraxidin from Acanthopanax senticosus, the adsorption and desorption properties of 17 widely used commercial macroporous resins were evaluated. According to our results, HPD100C, which adsorbs by the molecular tiers model, was the best macroporous resin, offering higher adsorption and desorption capacities and higher adsorption speed for syringin, eleutheroside E and isofraxidin than other resins. Dynamic adsorption and desorption tests were carried out to optimize the process parameters. The optimal conditions were as follows: for adsorption, processing volume: 24 BV, flow rate: 2 BV/h; for desorption, ethanol-water solution: 60:40 (v/v), eluent volume: 4 BV, flow rate: 3 BV/h. Under the above conditions, the contents of syringin, eleutheroside E and isofraxidin increased 174-fold, 20-fold and 5-fold and their recoveries were 80.93%, 93.97% and 93.79%, respectively.

Ultrasound-assisted extraction of syringin from the bark of Ilex rotunda thumb using response surface methodology

In this work, a rapid extraction method based on ultrasound-assisted extraction (UAE) of syringin from the bark of Ilex rotunda Thumb using response surface methodology (RSM) is described. The syringin was analyzed and quantified by high performance liquid chromatography coupled with UV detection (HPLC-UV). The extraction solvent, extraction temperature and extraction time, the three main factors for UAE, were optimized with Box-Behnken design (BBD) to obtain the highest extraction efficiency. The optimal conditions were the use of a sonication frequency of 40 kHz, 65% methanol as the solvent, an extraction time of 30 min and an extraction temperature of 40 °C. Using these optimal conditions, the experimental values agreed closely with the predicted values. The analysis of variance (ANOVA) indicated a high goodness of model fit and the success of the RSM method for optimizing syringin extraction from the bark of I. rotunda.

Electroacupuncture-induced cholinergic nerve activation enhances the hypoglycemic effect of exogenous insulin in a rat model of streptozotocin-induced diabetes

The aim of this study is to explore the mechanisms by which electroacupuncture (EA) enhances the hypoglycemic effect of exogenous insulin in a streptozotocin- (STZ-) diabetic rats. Animals in the EA group were anesthetized and subjected to the insulin challenge test (ICT) and EA for 60 minutes. In the control group, rats were subjected to the same treatment with the exception of EA stimulation. Blood samples were drawn to measure changes in plasma glucose, free fatty acids (FFA), and insulin levels. Western blot was used to assay proteins involved in insulin signaling. Furthermore, atropine, hemicholinium-3 (HC-3), and Eserine were used to explore the relationship between EA and cholinergic nerve activation during ICT. EA augmented the blood glucose-lowering effects of EA by activating the cholinergic nerves in STZ rats that had been exposed to exogenous insulin. This phenomenon may be related to enhancement of insulin signaling rather than to changes in FFA concentration.

Electroacupuncture at the Zusanli (ST-36) Acupoint Induces a Hypoglycemic Effect by Stimulating the Cholinergic Nerve in a Rat Model of Streptozotocine-Induced Insulin-Dependent Diabetes Mellitus

Animal studies have shown that electroacupuncture (EA) at Zusanli (ST-36) and Zhongwan (CV-12) acupoints reduces plasma glucose concentrations in rats with type II diabetes. However, whether EA reduces plasma glucose levels in type I diabetes is still unknown. In this study, we explore the various non-insulin-dependent pathways involved in EA-induced lowering of plasma glucose. Streptozotocin (STZ) (60 mg kg⁻¹, i.v.) was administered via the femoral vein to induce insulin-dependent diabetes in non-adrenalectomized and in adrenalectomomized rats. EA (15 Hz) was applied for 30 min to bilateral ST-36 acupoints after administration of Atropine (0.1 mg kg⁻¹ i.p.), Eserine (0.01 mg kg⁻¹ i.p.), or Hemicholinium-3 (5 μg kg⁻¹ i.p.) in non-adrenalectomized rats. Rats administered acetylcholine (0.01 mg kg⁻¹ i.v.) did not undergo EA. Adrenalectomized rats underwent EA at bilateral ST-36 acupoints without further treatment. Blood samples were drawn from all rats before and after EA to measure changes in plasma glucose levels. Expression of insulin signaling proteins (IRS1, AKT2) in atropine-exposed rats before and after EA was measured by western blot. Atropine and hemicholinium-3 completely blocked the plasma glucose lowering effects of EA, whereas eserine led to a significant hypoglycemic response. In addition, plasma glucose levels after administration of acetylcholine were significantly lower than the fasting glucose levels. In STZ-adrenalectomized rats, EA did not induce a hypoglycemic response. EA stimulated the expression of IRS1 and AKT2 and atropine treatment blocked the EA-induced expression of those insulin signaling proteins. Taken together, EA at the ST-36 acupoint reduces plasma glucose concentrations by stimulating the cholinergic nerves.

Activation of muscarinic M-1 cholinoceptors by curcumin to increase glucose uptake into skeletal muscle isolated from Wistar rats

Curcumin, an active principle contained in rhizome of Curcuma longa, has been mentioned to show merit for diabetes through its anti-oxidative and anti-inflammatory properties. In the present study, we found that curcumin caused a concentration-dependent increase of glucose uptake into skeletal muscle isolated from Wistar rats. This action was inhibited by pirenzepine at concentration enough to block muscarinic M-1 cholinoceptor (M(1)-mAChR). In radioligand binding assay, the binding of [(3)H]-pirenzepine was also displaced by curcumin in a concentration-dependent manner. In the presence of inhibitors for PLC-PI3K pathway, either U73122 (phospholipase C inhibitor) or LY294002 (phosphoinositide 3-kinase inhibitor), curcumin-stimulated glucose uptake into skeletal muscle was markedly reduced. In Western blotting analysis, the membrane protein level of glucose transporter 4 (GLUT4) increased by curcumin was also reversed by blockade of M(1)-mAChR or PLC-PI3K pathway in a same manner. In conclusion, the obtained results suggest that curcumin can activate M(1)-mAChR at concentrations lower than to scavenge free radicals for increase of glucose uptake into skeletal muscle through PLC-PI3-kinase pathway.