Protein tyrosine phosphatase 1B inhibitors isolated from Artemisia roxburghiana

The effects of ursolic acid on cardiometabolic risk factors: a systematic review and meta-analysis

Aim: Ursolic acid (UA) has an important biological role in the fight against fat accumulation, insulin resistance, obesity and inflammation. Therefore, in the current review and meta-analysis work, we investigate the effects of UA (dosage range is 50.94 to 450 mg/day) on cardiometabolic risk factors. Materials & methods: After searching the studies up to February 2023, six articles were included in the study. Results: The pooled effect size showed that UA supplementation didn't significantly change body weight, body mass index, waist circumference, body fat percentage, lean body mass, systolic blood pressure, diastolic blood pressure, fasting blood glucose, insulin, triglyceride and high-density lipoprotein compared with control groups. Conclusion: UA supplementation had no significant effect on the cardiometabolic risk factors in adults.

Classification, biosynthesis, and biological functions of triterpene esters in plants

Triterpene esters comprise a class of secondary metabolites that are synthesized by decorating triterpene skeletons with a series of oxidation, glycosylation, and acylation modifications. Many triterpene esters with important bioactivities have been isolated and identified, including those with applications in the pesticide, pharmaceutical, and cosmetic industries. They also play essential roles in plant defense against pests, diseases, physical damage (as part of the cuticle), and regulation of root microorganisms. However, there has been no recent summary of the biosynthetic pathways and biological functions of plant triterpene esters. Here, we classify triterpene esters into five categories based on their skeletons and find that C-3 oxidation may have a significant effect on triterpenoid acylation. Fatty acid and aromatic moieties are common ligands present in triterpene esters. We further analyze triterpene ester synthesis-related acyltransferases (TEsACTs) in the triterpene biosynthetic pathway. Using an evolutionary classification of BAHD acyltransferases (BAHD-ATs) and serine carboxypeptidase-like acyltransferases (SCPL-ATs) in Arabidopsis thaliana and Oryza sativa, we classify 18 TEsACTs with identified functions from 11 species. All the triterpene-skeleton-related TEsACTs belong to BAHD-AT clades IIIa and I, and the only identified TEsACT from the SCPL-AT family belongs to the CP-I subfamily. This comprehensive review of the biosynthetic pathways and bioactivities of triterpene esters provides a foundation for further study of their bioactivities and applications in industry, agricultural production, and human health.

Design, synthesis and biological evaluation of chalcone derivatives as potent and orally active hCYP3A4 inhibitors

Human cytochrome P450 3A4 (hCYP3A4), one of the most important drug-metabolizing enzymes, catalyze the metabolic clearance of ∼50% therapeutic drugs. CYP3A4 inhibitors have been used for improving the in vivo efficacy of hCYP3A4-substrate drugs. However, most of existing hCYP3A4 inhibitors may trigger serious adverse effects or undesirable effects on endogenous metabolism. This study aimed to discover potent and orally active hCYP3A4 inhibitors from chalcone derivatives and to test their anti-hCYP3A4 effects both in vitro and in vivo. Following three rounds of screening and structural optimization, the isoquinoline chalcones were found with excellently anti-hCYP3A4 effects. SAR studies showed that introducing an isoquinoline ring on the A-ring significantly enhanced anti-CYP3A4 effect, generating A10 (IC50 = 102.10 nM) as a promising lead compound. The 2nd round of SAR studies showed that introducing a substituent group at the para position of the carbonyl group on B-ring strongly improved the anti-CYP3A4 effect. As a result, C6 was identified as the most potent hCYP3A4 inhibitor (IC50 = 43.93 nM) in human liver microsomes (HLMs). C6 also displayed potent anti-hCYP3A4 effect in living cells (IC50 = 153.00 nM), which was superior to the positive inhibitor ketoconazole (IC50 = 251.00 nM). Mechanistic studies revealed that C6 could potently inhibit CYP3A4-catalyzed N-ethyl-1,8-naphthalimide (NEN) hydroxylation in a competitive manner (Ki = 30.00 nM). Moreover, C6 exhibited suitable metabolic stability in HLMs and showed good safety profiles in mice. In vivo tests demonstrated that C6 (100 mg/kg, orally administration) significantly increased the AUC(0-inf) of midazolam by 3.63-fold, and strongly prolonged its half-life by 1.66-fold compared with the vehicle group in mice. Collectively, our findings revealed the SARs of chalcone derivatives as hCYP3A4 inhibitors and offered several potent chalcone-type hCYP3A4 inhibitors, while C6 could serve as a good lead compound for developing novel, orally active CYP3A4 inhibitors with improved druglikeness properties.

Modulation of Insulin Resistance by Silybum marianum Leaves, and its Synergistic Efficacy with Gymnema sylvestre, Momordica charantia, Trigonella-foenum graecum Against Protein Tyrosine Phosphatase 1B

Prolonged insulin resistance is considered one of the reasons for Type 2 Diabetes Mellitus. Upregulation of Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin signalling, has been well studied as a key regulator in prognosis to insulin resistance. It has been widely studied as a desirable molecular therapeutic target. The study aimed to evaluate the efficacy of leaf extract of the medicinal plants Silybum marianum on the inhibition of PTP1B activity. It also explored the synergistic effect with extracts of Gymnema sylvestre (leaves), Momordica charantia (seeds), and Trigonella foenum graecum (seeds). The S. marianum leaves showed dose-dependent inhibition of PTP1B ranging from 9.48-47.95% (25-1000 μg mL-1). Assay with individual plant extracts showed comparatively lesser inhibition of PTP1B as compared to metformin as a control (38% inhibition). However, a synergistic effect showed nearly 45% PTP1B inhibition (higher than metformin) after the assay was done with selected four plant extracts in combination. The effect of leaf extracts of S. marianum was studied for glucose uptake efficiency in yeast cell lines which was found to be increased by 23% as compared to the control (without extract). Metformin improves glucose upake by yeast cells by ~15-31%. GC-MS analysis revealed 23 phytochemicals, some of which possessed anti-diabetic properties. A dose-dependent increase in antioxidant activity of S. marianum leaves extracts was observed (40-53%). The findings of the study highlighted the presence of various phytochemicals in leaves extracts that are effective against PTP1B inhibition and may help in reinvigorating drug development.

Design and Synthesis of Novel Betulin Derivatives Containing Thio-/Semicarbazone Moieties as Apoptotic Inducers through Mitochindria-Related Pathways

Two new series of betulin derivatives with semicarbazone (7a-g) or thiosemicarbazone (8a-g) groups at the C-28 position were synthesized. All compounds were evaluated for their in vitro cytotoxicities in human hepatocellular carcinoma cells (HepG2), human breast carcinoma cells (MCF-7), human lung carcinoma cells (A549), human colorectal cells (HCT-116) and normal human gastric epithelial cells (GES-1). Among these compounds, 8f displayed the most potent cytotoxicity with an IC₅₀ value of 5.86 ± 0.61 μM against MCF-7 cells. Furthermore, the preliminary mechanism studies in MCF-7 cells showed that compound 8f could trigger the intracellular mitochondrial-mediated apoptosis pathway by losing MMP level, which was related with the upregulation of Bax, P53 and cytochrome c expression; the downregulation of Bcl-2 expression; activation of the expression levels of caspase-3, caspase-9, cleaved caspase-3 and cleaved caspase-9; and an increase in the amounts of intracellular reactive oxygen species. These results indicated that compound 8f may be used as a valuable skeleton structure for developing novel antitumor agents.

Synthesis and Cytotoxic Activity of Novel Betulin Derivatives Containing Hydrazide-Hydrazone Moieties

A series of novel betulin derivatives containing hydrazide-hydrazone moieties were synthesized. All compounds were evaluated for their cytotoxicity against four human carcinoma cell lines (HepG2, A549, MCF-7 and HCT-116) and a normal human gastric epithelial cell line (GES-1). Among them, compound 6i was the most potent against HepG2 and MCF-7 cell lines, with IC50 values of 9.27 and 8.87 μM, respectively. The results suggest that the incorporation of a hydrazide-hydrazone side chain at the C-28 position of betulin is beneficial for compounds to display significant cytotoxicity. Compound 6i may be used as a promising skeleton for antitumor agents with improved efficacy.

Pyrazoles as novel protein tyrosine phosphatase 1B (PTP1B) inhibitors: An in vitro and in silico study

Type 2 diabetes mellitus (DM) is a complex chronic disorder and a major global health problem. Insulin resistance is the primary detectable abnormality and the main characteristic feature in individuals with type 2 DM. Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of the insulin signaling pathway, which dephosphorylates insulin receptor and insulin receptor substrates, suppressing the insulin signaling cascade. Therefore, the inhibition of PTP1B has become a potential strategy in the management of type 2 DM. In this study, a library of 22 pyrazoles was evaluated here for the first time against human PTP1B activity, using a microanalysis screening system. The results showed that 5-(2-hydroxyphenyl)-3-{2-[3-(4-nitrophenyl)-1,2,3,4-tetrahydronaphthyl]}-1-phenylpyrazole 20 and 3-(2-hydroxyphenyl)-5-{2-[3-(4-methoxyphenyl)]naphthyl}pyrazole 22 excelled as the most potent inhibitors of PTP1B, through noncompetitive inhibition mechanism. These findings suggest that the presence of additional benzene rings as functional groups in the pyrazole moiety increases the ability of pyrazoles to inhibit PTP1B. The most active compounds showed selectivity over the homologous T-cell protein tyrosine phosphatase (TCPTP). Molecular docking analyses were performed and revealed a particular contact signature involving residues like TYR46, ASP48, PHE182, TYR46, ALA217 and ILE219. This study represents a significant beginning for the design of novel PTP1B inhibitors.

Exploring the bioactivity of pentacyclic triterpenoids as potential antimycobacterial nutraceutics: Insights through comparative biomolecular modelling

A group of bioactive compounds known as triterpenoids, which are often found in plant materials, have been tested to possess nutritional and pharmaceutical activity. These plant components are referred to as nutraceuticals, and are used as therapeutic agents. In this study, we explore the interactions of betulinic acid (BA), oleanolic acid (OA), ursolic acid (UA), and maslinic acid (MA) against FadA5. Studies have identified FadA5, a trifunctional enzyme-like thiolase, as a target towards Mycobacterium tuberculosis inhibition. The investigation involves molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) applications. Analyses of the four pentacyclic triterpenoids binding to FadA5 showed appreciable bioactivity against FadA5. The application of two or more theoretical models to unravel ligand-enzyme binding energies can pave the way for accurate binding affinity prediction and validation.

Antidiabetic effect of aqueous-ethanol extract from the aerial parts of Artemisia roxburghiana

Artemisia roxburghiana is used for the management of diabetes mellitus in the Indian subcontinent. The present work aimed to validate the traditional claim of the plant in diabetes mellitus. In vitro studies were conducted using α-glucosidase and α-amylase assays whereas streptozotocin-nicotinamide-induced diabetic Wistar rats were used for in vivo study. The aqueous-ethanol extract from the aerial parts was found to exhibit α-glucosidase and α-amylase inhibitory activities with the IC₅₀ values of 31.0 and 17.2 mg/mL, respectively when compared with acarbose (IC₅₀ = 8.6 and 16.25 mg/mL, respectively). The extract showed a significant glucose-lowering effect in diabetic rats at the doses of 200 and 400 mg/kg in a dose-dependent manner, while acarbose (10 mg/kg) was used as a standard. The results revealed that A. roxburghiana aerial parts showed antidiabetic activity via inhibiting α-glucosidase and α-amylase enzymes. The present study also validated the ethnomedicinal claim of the plant in diabetes mellitus.

Protein Tyrosine Phosphatase 1B Inhibitors: A Novel Therapeutic Strategy for the Management of type 2 Diabetes Mellitus

Diabetes is one of the most common endocrine non-communicable metabolic disorders which is mainly caused either due to insufficient insulin or inefficient insulin or both together and is characterized by hyperglycemia. Diabetes emerged as a serious health issue in the industrialized and developing country especially in the Asian pacific region. Out of the two major categories of diabetes mellitus, type 2 diabetes is more prevalent, almost 90 to 95% cases, and the main cause of this is insulin resistance. The main cause of the progression of type 2 diabetes mellitus has been found to be insulin resistance. The type 2 diabetes mellitus may be managed by the change in lifestyle, physical activities, dietary modifications and medications. The major currently available management strategies are sulfonylureas, biguanides, thiazolidinediones, α-glucosidase inhibitors, dipeptidyl peptidase-IV inhibitors, and glucagon-like peptide-1 (GLP-1) agonist. Binding of insulin on the extracellular unit of insulin receptor sparks tyrosine kinase of the insulin receptor which induces autophosphorylation. The phosphorylation of the tyrosine is regulated by insulin and leptin molecules. Protein tyrosine phosphatase-1B (PTP1B) works as a negative governor for the insulin signalling pathways, as it dephosphorylates the tyrosine of the insulin receptor and suppresses the insulin signalling cascade. The compounds or molecules which inhibit the negative regulation of PTP1B can have an inductive effect on the insulin pathway and finally help in the management of diabetes mellitus. PTP1B could be an emerging therapeutic strategy for diabetes management. There are a number of clinical and basic research results which suggest that induced expression of PTP1B reduces insulin resistance. In this review, we briefly elaborate and explain the place of PTP1B and its significance in diabetes as well as a recent development in the PTP1B inhibitors as an antidiabetic therapy.

Chemistry, Biological Activities and In Silico Bioprospection of Sterols and Triterpenes from Mexican Columnar Cactaceae

The Cactaceae family is an important source of triterpenes and sterols. The wide uses of those plants include food, gathering, medicinal, and live fences. Several studies have led to the isolation and characterization of many bioactive compounds. This review is focused on the chemistry and biological properties of sterols and triterpenes isolated mainly from some species with columnar and arborescent growth forms of Mexican Cactaceae. Regarding the biological properties of those compounds, apart from a few cases, their molecular mechanisms displayed are not still fully understand. To contribute to the above, computational chemistry tools have given a boost to traditional methods used in natural products research, allowing a more comprehensive exploration of chemistry and biological activities of isolated compounds and extracts. From this information an in silico bioprospection was carried out. The results suggest that sterols and triterpenoids present in Cactaceae have interesting substitution patterns that allow them to interact with some bio targets related to inflammation, metabolic diseases, and neurodegenerative processes. Thus, they should be considered as attractive leads for the development of drugs for the management of chronic degenerative diseases.

Modified diterpenoids from the tuber of Icacina oliviformis as protein tyrosine phosphatase 1B inhibitors

Two modified diterpenoids featuring a novel 4,12-dioxatetracyclo[8.6.0.0^2,7.0^10,14]hexadecane core, together with a 3,4-seco-pimarane, a 3,4-seco-cleistanthane, and eight pimarane derivatives were isolated from the tuber of Icacina oliviformis.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Ethnomedicinal Investigation of Medicinal Plants of Chakrata Region (Uttarakhand) Used in the Traditional Medicine for Diabetes by Jaunsari Tribe

The Himalayan region is the treasure house of natural wealth, particularly of medicinal and aromatic plants. These plants are used by the Indian traditional healers for the past many centuries to treat various ailments such as skin disorders, asthma, diabetes, snake bite, fever, pain, eye diseases, diarrhoea, indigestion, jaundice, burn, wound, liver disorder, CNS disorders and urinary tract infection. The indigenous traditional knowledge of medicinal plants and therapies of various local communities has been lost due to changes in traditional culture and the introduction of modern technologies. Therefore, it is essential to explore the traditional knowledge of the indigenous medicinal plants mainly in such areas where there is a severe threat to natural vegetation owing to human inhabitation. The present study aimed to explore the medicinal plants of Chakrata region (Jaunsar-Bawar Hills), Uttarakhand, India used in the folk medicine for the management of diabetes by Jaunsari Tribe. In a comprehensive field survey, the information about the medicinal plants have been mainly collected from the traditional healers and other elderly people belong to the tribal community. All the information about the medicinal plants of the study area was documented in a field book. Various tools have been used to collect the samples for identification purpose and the authentication of the plants was done with the help of taxonomists. The literature on these plants was also searched from online (PubMed and Scopus) as well as from some textbooks and Ayurvedic classical texts. The present survey-based work described a total of 54 plants belonging to 47 genera and 30 families used in the traditional medicine for the management of diabetes in Chakrata region. The information gathered from the local community revealed that the plants are effective in diabetes and one can use most of them without consulting a practitioner or traditional healer. The literature revealed that most of the surveyed plants are already used in the preparation of various antidiabetic formulations such as Chandraprabha vati, Nishamalaki chunra, Amritamehari churna and Nisakathakadi kashayam along with various patent drugs which are frequently prescribed by the Ayurvedic practitioners in India. The present study explored the traditional as well as scientific knowledge on the antidiabetic plants used by the tribal community. The documented information on these plants can be further used by the scientific community to develop new drugs/formulations with the help of modern techniques.

Previously undescribed fridooleanenes and oxygenated labdanes from the brown seaweed Sargassum wightii and their protein tyrosine phosphatase-1B inhibitory activity

Previously undescribed fridooleanene triterpenoids 2α-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien-20-propyl-21-hex-4'(Z)-enoate, 2α-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien-20-prop-2(E)-en-21-butanoate and oxygenated labdane diterpenoids 2α-hydroxy-8(17), (12E), 14-labdatriene, 3β, 6β, 13α-tri hydroxy 8(17), 12E, 14-labdatriene were purified from the ethyl acetate-methanol and dichloromethane fractions of the air-dried thalli of Sargassum wightii (Sargassaceae), a brown seaweed collected from the Gulf-of-Mannar of Penninsular India. Inhibitory potential of Δ12 oleanenes towards protein tyrosine phosphatase-1B, the critical regulator of insulin-receptor activity were found to be significantly greater (IC50 0.1 × 10-2 and 0.09 × 10-2 mg/mL, respectively) than the standard sodium metavanadate (IC50 0.31 × 10-2 mg/mL). Fridooleanene triterpenoids displayed greater antioxidant activities (IC50DPPH 0.16-0.18 mg/mL) than the commercially available antioxidants, butylated hydroxytoluene and α-tocopherol (IC50DPPH 0.25 and 0.63 mg/mL, respectively). In general, the oxygenated labdane diterpenoids displayed significantly lesser antioxidant and tyrosine phosphatase-1B inhibitory properties than those exhibited by the fridooleanenes. Bioactivities of the titled compounds were primarily determined by the electronic and lipophilic parameters and not by the steric descriptors. Molecular docking simulations and kinetic studies were employed to describe the tyrosine phosphatase-1B inhibitory mechanism. The previously undescribed fridooleanene triterpenoids might be used as potential anti-hyperglycaemic pharmacophore leads to reduce the risk of elevated postprandial glucose levels.

Screening for Triterpenoid Saponins in Plants Using Hyphenated Analytical Platforms

Recently the number of studies investigating triterpenoid saponins has drastically increased due to their diverse and potentially attractive biological activities. Currently the literature contains chemical structures of few hundreds of triterpenoid saponins of plant and animal origin. Triterpenoid saponins consist of a triterpene aglycone with one or more sugar moieties attached to it. However, due to similar physico-chemical properties, isolation and identification of a large diversity of triterpenoid saponins remain challenging. This study demonstrates a methodology to screen saponins using hyphenated analytical platforms, GC-MS, LC-MS/MS, and LC-SPE-NMR/MS, in the example of two different phenotypes of the model plant Barbarea vulgaris (winter cress), glabrous (G) and pubescent (P) type that are known to differ by their insect resistance. The proposed methodology allows for detailed comparison of saponin profiles from intact plant extracts as well as saponin aglycone profiles from hydrolysed samples. Continuously measured 1D proton NMR data during LC separation along with mass spectrometry data revealed significant differences, including contents of saponins, types of aglycones and numbers of sugar moieties attached to the aglycone. A total of 49 peaks were tentatively identified as saponins from both plants; they are derived from eight types of aglycones and with 2–5 sugar moieties. Identification of two previously known insect-deterrent saponins, hederagenin cellobioside and oleanolic acid cellobioside, demonstrated the applicability of the methodology for relatively rapid screening of bioactive compounds.