Hypoglycemic action of borapetoside A from the plant Tinospora crispa in mice

A colorimetric sensing strategy based on chitosan-stabilized platinum nanoparticles for quick detection of α-glucosidase activity and inhibitor screening

α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O2. The catalytic hydrolysis of 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1-1.0 U mL-1 and the detection limit was 0.026 U mL-1. Additionally, the half-maximal inhibition value (IC50) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769 mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery.

Exploration of the main active metabolites from Tinospora crispa (L.) Hook. f. & Thomson stem as insulin sensitizer in L6.C11 skeletal muscle cell by integrating in vitro, metabolomics, and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora crispa (L.) Hook. f. & Thomson stem (TCS) has long been used as folk medicine for the treatment of diabetes mellitus. Previous study revealed that TCS possesses multi-ingredients and multi-targets characteristic potential as insulin sensitizer activity. However, its mechanisms of action and molecular targets are still obscure.

AIM OF THE STUDY

In the present study, we investigated the effects of TCS against insulin resistance in muscle cells through integrating in vitro experiment and identifying its active biomarker using metabolomics and in molecular docking validation.

MATERIALS AND METHODS

We used centrifugal partition chromatography (CPC) to isolate 33 fractions from methanolic extract of TCS, and then used UHPLC-Orbitrap-HRMS to identify the detectable metabolites in each fraction. We assessed the insulin sensitization activity of each fraction using enzyme-linked immunosorbent assay (ELISA), and then used confocal immunocytochemistry microscopy to measure the translocation of glucose transporter 4 (GLUT4) to the cell membrane. The identified active metabolites were further simulated for its molecular docking interaction using Autodock Tools.

RESULTS

The polar fractions of TCS significantly increased insulin sensitivity, as measured by the inhibition of phosphorylated insulin receptor substrate-1 (pIRS1) at serine-312 residue (ser312) also the increasing number of translocated GLUT4 and glycogen content. We identified 58 metabolites of TCS, including glycosides, flavonoids, alkaloids, coumarins, and nucleotides groups. The metabolomics and molecular docking simulations showed the presence of minor metabolites consisting of tinoscorside D, higenamine, and tinoscorside A as the active compounds.

CONCLUSIONS

Our findings suggest that TCS is a promising new treatment for insulin resistance and the identification of the active metabolites in TCS could lead to the development of new drugs therapies for diabetes that target these pathways.

Tinopanoids K-T, clerodane diterpenoids with anti-inflammatory activity from Tinospora crispa

A total of 17 structurally diverse clerodane diterpenoids, including ten undescribed clerodane diterpenoids (tinopanoids K-T, 1-10) and seven known compounds (11-17), were isolated from the vines and leaves of Tinospora crispa. Compound 3 has not only bear the dominant substituents of γ-hydroxy-α, β-unsaturated-γ-lactone with anti-inflammatory activity, but also a ternary epoxy structure at C-3/C-4. The planar structures and relative configurations of the clerodane diterpenoids were elucidated by spectroscopic data interpretation. The absolute configurations of compounds 1, 4, 8 and 13 were determined by single-crystal X-ray crystallographic, while that of compound 3 was determined using computed ECD data and single crystal X-ray diffraction of related p-bromobenzoate ester (3a). Subsequently, all compounds were evaluated for their inhibitory effect on nitric oxide (NO) production of LPS-activated BV-2 cells, and compounds 3 and 8 exhibited better NO inhibitory potency, with IC50 values of 5.6 and 13.8 μM than the positive control minocycline (Mino, IC50 = 22.9 μM). The corresponding results of western blot analysis and qRT-PCR revealed that compound 3 can significantly inhibit the inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expressions, mRNA levels of pro-inflammatory cytokins of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) and interleukin 1β (IL-1β). The underlying mechanism by which compound 3 exerted anti-neuroinflammatory effects was investigated by western blot and immunofluorescence assay, which suggested compound 3 inhibited LPS induced neuroinflammation via the suppression of toll-like receptor 4 (TLR4) dependent Signal Transducer and Activator of Transcription 3 (Stat3) and mitogen-activated protein kinase (MAPK) signaling pathways, and the activation of Heme Oxygenase-1 (HO-1) mediated signals.

Diterpenoids and Their Glycosides from the Stems of Tinospora crispa with Beta-Cell Protective Activity

Seven previously undescribed diterpenoids, tinocrisposides A-D (1-4) and borapetic acids A (5), B (6), and C (7), together with 16 known compounds, were isolated from the stem of Tinospora crispa (Menispermaceae). The structures of the new isolates were elucidated by spectroscopic and chemical methods. The β-cell protective effect of the tested compounds was examined on insulin-secreting BRIN-BD11 cells under dexamethasone treatment. Diterpene glycosides 12, 14-16, and 18 presented a substantial protective effect on BRIN-BD11 cells treated with dexamethasone in a dose-dependent manner. Compounds 4 and 17 with two sugar moieties exhibited clear protective effects on β-cells.

Network pharmacology integrated molecular dynamics reveals the bioactive compounds and potential targets of Tinospora crispa Linn. as insulin sensitizer

Insulin resistance is a metabolic disorder characterized by the decreased response to insulin in muscle, liver, and adipose cells. This condition remains a complex phenomenon that involves several genetic defects and environmental stresses. In the present study, we investigated the mechanism of known phytochemical constituents of Tinospora crispa and its interaction with insulin-resistant target proteins by using network pharmacology, molecular docking, and molecular dynamics (MD) simulation. Tinoscorside A, Makisterone C, Borapetoside A and B, and β sitosterol consider the main phytoconstituents of Tinospora crispa by its binding with active sites of main protein targets of insulin resistance potential therapy. Moreover, Tinoscorside A was revealed from the docking analysis as the ligand that binds most strongly to the target protein, PI3K. This finding was strengthened by the results of MD simulation, which stated that the conformational stability of the ligand-protein complex was achieved at 15 ns and the formation of hydrogen bonds at the active site. In conclusion, Tinospora crispa is one of the promising therapeutic agent in type 2 diabetes mellitus management. Regulation in glucose homeostasis, adipolysis, cell proliferation, and antiapoptosis are predicted to be the critical mechanism of Tinospora crispa as an insulin sensitizer.

Potential of Diterpenes as Antidiabetic Agents: Evidence from Clinical and Pre-Clinical Studies

Diterpenes are a diverse group of structurally complex natural products with a wide spectrum of biological activities, including antidiabetic potential. In the last 25 years, numerous diterpenes have been investigated for antidiabetic activity, with some of them reaching the stage of clinical trials. However, these studies have not been comprehensively reviewed in any previous publication. Herein, we critically discussed the literature on the potential of diterpenes as antidiabetic agents, published from 1995 to September, 2021. In the period under review, 427 diterpenes were reported to have varying degrees of antidiabetic activity. Steviol glycosides, stevioside (1) and rebaudioside A (2), were the most investigated diterpenes with promising antidiabetic property using in vitro and in vivo models, as well as human subjects. All the tested pimaranes consistently showed good activity in preclinical evaluations against diabetes. Inhibitions of α-glucosidase and protein tyrosine phosphatase 1B (PTP 1B) activities and peroxisome proliferator-activated receptors gamma (PPAR-γ) agonistic property, were the most frequently used assays for studying the antidiabetic activity of diterpenes. The molecular mechanisms of action of the diterpenes include increased GLUT4 translocation, and activation of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK)-dependent signaling pathways. Our data revealed that diterpenes hold promising antidiabetic potential. Stevioside (1) and rebaudioside A (2) are the only diterpenes that were advanced to the clinical trial stage of the drug discovery pipeline. Diterpenes belonging to the abietane, labdane, pimarane and kaurane class have shown promising activity in in vitro and in vivo models of diabetes and should be further investigated.

Higenamine in Plants as a Source of Unintentional Doping

BACKGROUND

Higenamine is a β₂ agonist of plant origin. The compound has been included in WADA's prohibited list since 2017. Higenamine may be detected in different plants and many food supplements of natural origin.

METHODS

Our literature search was conducted through PubMed, Science Direct, Google Scholar, and Web of Science studies investigating the presence of higenamine in plants that are used in traditional folk medicine or included in food supplements. Our study aimed to assess the risk of adverse analytical findings caused by higenamine-containing plants.

RESULTS

Based on our literature search, Nelumbo nucifera, Tinospora crispa, Nandina domestica, Gnetum parvifolium, Asarum siebodii,Asarum heterotropoides, Aconitum carmichaelii, and Aristolochia brasiliensis are higenamine-containing plants. Based on data from Eastern folk medicine, these plants can provide numerous health benefits. Professional athletes likely ingest these plants without knowing that they contain higenamine; these herbs are used in treatments for different conditions and various foods/food supplements in addition to folk medicine.

CONCLUSION

Athletes and their teams must be aware of the issues associated with the use of plant-based products. They should avoid consuming higenamine-containing plants during and outside of competition periods.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

A colorimetric method for screening α-glucosidase inhibitors from flavonoids using 3,3',5,5'-tetramethylbenzidine as a chromogenic probe

A facile and novel colorimetric method for screening of α-glucosidase inhibitors (AGIs) from flavonoids using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic probe is proposed. This method is based on the colorimetric detection of ascorbic acid (AA) through the TMB oxidation reaction catalyzed by horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H₂O₂). In the TMB/H₂O₂/HRP system, HRP catalyzes the oxidation of H₂O₂ to ‧OH radical which oxidizes TMB to blue-colored oxidized TMB (oxTMB). In the presence of AA, the production of ‧OH radical is suppressed and causes the decrease of oxTMB, resulting in the fading of the blue color and the decrease of absorbance at 652 nm. Based on this, the existence of AA can be facilely identified. In the 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2 G)/α-glucosidase (α-Glu) system, the produced AA inhibits the oxidation of TMB to blue-colored oxTMB. In the presence of AGIs, the production of AA is inhibited, which inhibits the reduction of oxTMB, resulting in a blue color recovery and an increase of the absorbance at 652 nm. Based on this, the colorimetric method is developed for screening of AGIs from 7 flavonoids.

A new dimeric protoberberine alkaloid and other compounds from the tubers of Tinospora dentata

A new dimeric quaternary protoberberine alkaloid, bispalmatrubine (1), and thirteen known compounds (2-14) were purified from the tubers of Tinospora dentata. Their structures were determined by spectroscopic and spectrometric analytical methods. Among the isolates, eight compounds were examined for their in vitro anti-inflammatory potential and several tested alkaloids displayed moderate inhibitory effects of N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation and elastase release.

Beyond model interpretability using LDA and decision trees for α-amylase and α-glucosidase inhibitor classification studies

In this report are used two data sets involving the main antidiabetic enzyme targets α-amylase and α-glucosidase. The prediction of α-amylase and α-glucosidase inhibitory activity as antidiabetic is carried out using LDA and classification trees (CT). A large data set of 640 compounds for α-amylase and 1546 compounds in the case of α-glucosidase are selected to develop the tree model. In the case of CT-J48 have the better classification model performances for both targets with values above 80%-90% for the training and prediction sets, correspondingly. The best model shows an accuracy higher than 95% for training set; the model was also validated using 10-fold cross-validation procedure and through a test set achieving accuracy values of 85.32% and 86.80%, correspondingly. Additionally, the obtained model is compared with other approaches previously published in the international literature showing better results. Finally, we can say that the present results provided a double-target approach for increasing the estimation of antidiabetic chemicals identification aimed by double-way workflow in virtual screening pipelines.

Efficiency of Tinospora crispa against Culex quinquefasciatus larva

Tinospora crispa stem aqueous extractions for various time durations were determined regarding their total phenolic content and their larvicidal abilities. The results revealed that the total phenolic content in 1-, 3-, 5-, 10-, and 24-h extracts were 8.26, 8.43, 13.57, 12.52, and 12.43 mg/g gallic acid equivalent, respectively. The 5-h extract of T. crispa was evaluated against Culex quinquefasciatus mosquito larva in concentrations 3.125, 6.25, 12.5, and 25 mg/l, by determining the lethal concentration (LC) within 24 h and by histopathological analysis. The 24-h LC₅₀ and LC₉₀ values were 16.95 and 30.12 mg/l, respectively. The histopathological lesions after exposure to 50% of the 24-h LC₅₀ were observed primarily in the midgut of the larva. The lesions observed were for the example epithelial cells lifting from the basement membrane, cell elongation protruding into the lumen, brush border disrupting with absent microvilli, and vesicle appearance. The present study indicated that the aqueous extract of this herb may have a suitable property for a larvicidal natural product and may replace harmful chemical pesticides.

Chemical Constituents from the Stems of Tinospora sinensis and Their Bioactivity

Fifty-seven compounds were purified from the stems of Tinospora sinensis, including three new compounds characterized as a lignan (1), a pyrrole alkaloid (11), and a benzenoid (17), respectively. Their structures were elucidated and established by various spectroscopic and spectrometric analytical methods. Among the isolates, fifteen compounds were examined for their anti-inflammatory potential in vitro. The results showed that several compounds displayed moderate inhibition of N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation and elastase release.

Clerodane furanoditerpenoids as the probable cause of toxic hepatitis induced by Tinospora crispa

Tinospora crispa is a popular traditional herbal plant commonly used throughout the world for treatment of various diseases, in particular type 2 diabetes mellitus. We report here a new case of toxic hepatitis in a 57-year old male patient in the French West Indies following the consumption of two aqueous extracts of fresh Tinospora crispa stems. It thus differs from two previously reported cases that concerned the chronic intake of powdered dry stems delivered in solid oral dosage forms (i.e. pellets and tablets). Liquid Chromatography-Diode Array Detection-Mass Spectrometry (LC/DAD/MS) analyses were performed on an aqueous extract of the offending sample that mimics the swallowed preparation. They revealed the presence of species-specific molecular marker borapetoside C (1) and thus enabled an unambiguous phytochemical identification. The exploration of tandem MS/MS data obtained by ultra-high performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-HRMS) allowed the identification of 17 additional cis-clerodane-type furanoditerpenoid lactones, analogues of 1. These results support the hypothesis that the mechanisms underlying hepatotoxicity of Tinospora crispa are the same as those encountered with furanoditerpenoids-containing plants such as Teucrium chamaedrys or Dioscorea bulbifera. In the context of type 2 diabetes treatment, we recommend that Tinospora crispa intake should be more closely monitored for signs of hepatotoxicity.

Genus Tinospora: Ethnopharmacology, Phytochemistry, and Pharmacology

The genus Tinospora includes 34 species, in which several herbs were used as traditional medicines by indigenous groups throughout the tropical and subtropical parts of Asia, Africa, and Australia. The extensive literature survey revealed Tinospora species to be a group of important medicinal plants used for the ethnomedical treatment of colds, headaches, pharyngitis, fever, diarrhea, oral ulcer, diabetes, digestive disorder, and rheumatoid arthritis. Indian ethnopharmacological data points to the therapeutic potential of the T. cordifolia for the treatment of diabetic conditions. While Tinospora species are confusing in individual ingredients and their mechanisms of action, the ethnopharmacological history of those plants indicated that they exhibit antidiabetic, antioxidation, antitumor, anti-inflammation, antimicrobial, antiosteoporosis, and immunostimulation activities. While the clinical applications in modern medicine are lacking convincing evidence and support, this review is aimed at summarizing the current knowledge of the traditional uses, phytochemistry, biological activities, and toxicities of the genus Tinospora to reveal its therapeutic potentials and gaps, offering opportunities for future researches.

Tinospora crispa (L.) Hook. f. & Thomson: A Review of Its Ethnobotanical, Phytochemical, and Pharmacological Aspects

Tinospora crispa (L.) Hook. f. & Thomson (Menispermaceae), found in the rainforests or mixed deciduous forests in Asia and Africa, is used in traditional medicines to treat numerous health conditions. This review summarizes the up-to-date reports about the ethnobotany, phytochemistry, pharmacological activities, toxicology, and clinical trials of the plant. It also provides critical assessment about the present knowledge of the plant which could contribute toward improving its prospect as a source of lead molecules for drug discovery. The plant has been used traditionally in the treatment of jaundice, rheumatism, urinary disorders, fever, malaria, diabetes, internal inflammation, fracture, scabies, hypertension, reducing thirst, increasing appetite, cooling down the body temperature, and maintaining good health. Phytochemical analyses of T. crispa revealed the presence of alkaloids, flavonoids, and flavone glycosides, triterpenes, diterpenes and diterpene glycosides, cis clerodane-type furanoditerpenoids, lactones, sterols, lignans, and nucleosides. Studies showed that the crude extracts and isolated compounds of T. crispa possessed a broad range of pharmacological activities such as anti-inflammatory, antioxidant, immunomodulatory, cytotoxic, antimalarial, cardioprotective, and anti-diabetic activities. Most pharmacological studies were based on crude extracts of the plant and the bioactive compounds responsible for the bioactivities have not been well identified. Further investigations are required to transform the experience-based claims on the use of T. crispa in traditional medicine practices into evidence-based information. The plant extract used in pharmacological and biological studies should be qualitatively and quantitatively analyzed based on its biomarkers. There should be detail in vitro and in vivo studies on the mechanisms of action of the pure bioactive compounds and more elaborate toxicity study to ensure safety of the plant for human use. More clinical trials are encouraged to be carried out if there are sufficient preclinical and safety data.

α-Glucosidase inhibitory activities of phenolic acid amides with l-amino acid moiety

Phenolic acid amides with a l-amino acid moiety showed excellent inhibitory activity on α-glucosidase.

Therapeutic effect of Zhuang herb Hanyitai on duck hepatitis B

AIM: To investigate the therapeutic effect of Zhuang herb Hanyitai on liver function, viral replication, immune regulation and liver inflammation in a duck model infected by duck hepatitis B virus (DHBV).

METHODS: Duck hepatitis B was induced by intraperitoneal injection of DHBV positive serum into one-day-old Guangxi sheldrakes. On the day before treatment (T0), 7 d (T7) and 14 d (T14) during treatment, and 3 d (P3) after treatment, jugular blood and liver tissue samples were collected to detect aspartate aminotransferase (ALT), alanine aminotransferase (AST), interleukin-2 (IL-2), DHBV DNA, and liver pathology.

RESULTS: In the model group, ALT, AST and IL-2 levels were significantly increased after DHBV infection for one week and two weeks (P = 0.028, 0.036; P = 0.005, 0.04; P = 0.045), the amount of virus was relatively stable, and severe fatty degeneration was observed in liver tissues. In the lamivudine group, ALT and IL-2 levels were significantly decreased after treatment for one week and two weeks (P = 0.001, 0.042; P = 0.023), AST level showed no significant changes, the replication of virus was significantly inhibited (P = 0.034; 0.007), without rebounding after medication withdrawal for three days (P = 0.013), and liver tissue pathology showed moderate liver steatosis. In the high dose Hanyitai group, ALT, AST, and IL-2 levels were significantly reduced after treatment for one week and two weeks (P = 0.047, 0.035; P = 0.007, 0.003; P = 0.026, 0.049), the replication of virus was inhibited significantly as the lamivudine group (P = 0.025; P = 0.012; P = 0.011), and liver tissue pathology displayed moderate liver steatosis. In the usual dose Hanyitai group, ALT, AST, and IL-2 levels were significantly reduced after treatment for one week and two weeks (P = 0.015; P = 0.038; P = 0.024, 0.004), but at T14, ALT and AST level rebounded, the replication of virus was inhibited moderately, and moderate or severe steatosis was noted.

CONCLUSION: Hanyitai can reduce transaminase levels, inhibit DHBV DNA replication, and reduce IL-2 secretion in a dose-dependent manner. Hanyitai could protect liver cells, relieve hepatic steatosis, and reduce acute immunological liver injury.