Characterization of the inhibitory activity of natural tanshinones from Salvia miltiorrhiza roots on protein tyrosine phosphatase 1B

Insights on therapeutic approaches of natural anti-Alzheimer's agents in the management of Alzheimer's disease: A future perspective

In the current scenario, Alzheimer's disease is a complex, challenging, and arduous health issue, and its prevalence, together with comorbidities, is accelerating around the universe. Alzheimer's disease is becoming a primary concern that significantly impacts an individual's status in life. The traditional treatment of Alzheimer's disease includes some synthetic drugs, which have numerous dangerous side effects, a high risk of recurrence, lower bioavailability, and limited treatment. Hence, the current article is a detailed study and review of all known information on plant-derived compounds as natural anti-Alzheimer's agents, including their biological sources, active phytochemical ingredients, and a possible mode of action. With the help of a scientific data search engine, including the National Center for Biotechnology Information (NCBI/PubMed), Science Direct, and Google Scholar, analysis from 2001 to 2024 has been completed. This article also described clinical studies on phytoconstituents used to treat Alzheimer's disease. Plant-derived compounds offer promising alternatives to synthetic drugs in treating Alzheimer's disease, with the potential for improving cognitive function and slowing down the progression of the disease. Further research and clinical trials are needed to fully explore their therapeutic potential and develop effective strategies for managing this complex condition.

Evaluation of Phytochemistry and Antidiabetic Potential of an Astragalus Species (Astragalus kurdicus Boiss.)

Astragalus kurdicus Boiss. roots are used in folk medicine for antidiabetic purposes. Different Astragalus plant metabolites have a notable potential for antidiabetic activity through varying mechanisms. Herein, this study is designed to assess the antidiabetic activity of Astragalus kurdicus total (AKM: methanol extract, yield: 14.53 %) and sub-extracts (AKB: n-butanol, AKC: chloroform, AKW: water, AKH: hexane extracts), utilizing a range of diabetes-related in vitro methodologies, and to investigate the chemical composition of the plant. The highest astragaloside and saponin content was seen in AKB extract. Among the measured saponins, the abundance of Astragaloside IV (27.41 μg/mg in AKM) was the highest in high-performance thin-layer chromatography (HPTLC) analysis. Furthermore, flavonoid-rich AKC was found to be mostly responsible for the high antioxidant activity. According to the results of the activity tests, AKW was the most active extract in protein tyrosine phosphatase 1 B (PTP1B), dipeptidyl peptidase IV (DPP4), and α-amylase inhibition tests (percent inhibitions are: 87.17 %, 82.4 %, and 91.49 % respectively, at 1 mg/mL). AKM and AKW demonstrated the highest efficacy in stimulating the growth of prebiotic microorganisms and preventing the formation of advanced glycation end products (AGEs). Thus, for the first time, the antidiabetic activity of A. kurdicus was evaluated from various perspectives.

Advanced application of nanotechnology in active constituents of Traditional Chinese Medicines

Traditional Chinese Medicines (TCMs) have been used for centuries for the treatment and management of various diseases. However, their effective delivery to targeted sites may be a major challenge due to their poor water solubility, low bioavailability, and potential toxicity. Nanocarriers, such as liposomes, polymeric nanoparticles, inorganic nanoparticles and organic/inorganic nanohybrids based on active constituents from TCMs have been extensively studied as a promising strategy to improve the delivery of active constituents from TCMs to achieve a higher therapeutic effect with fewer side effects compared to conventional formulations. This review summarizes the recent advances in nanocarrier-based delivery systems for various types of active constituents of TCMs, including terpenoids, polyphenols, alkaloids, flavonoids, and quinones, from different natural sources. This review covers the design and preparation of nanocarriers, their characterization, and in vitro/vivo evaluations. Additionally, this review highlights the challenges and opportunities in the field and suggests future directions for research. Nanocarrier-based delivery systems have shown great potential in improving the therapeutic efficacy of TCMs, and this review may serve as a comprehensive resource to researchers in this field.

Reassessing the molecular structures of some previously isolated abietane diterpenoids with a naphthalene moiety and the structure-activity relationship (SAR) of quinone diterpenoids

Crystals of previously described para-naphthoquinone abietane diterpenoids 12,16-dideoxy-aegyptinone B and 12-deoxy-salvipisone were obtained from Zhumeria majdae Rech.f. & Wendelbo. However, single-crystal X-ray diffraction analysis followed by reinterpretation of their NMR data revealed that their structures require revision, and they should be revised to the two ortho-naphthoquinones, zhumerianone C and aethiopinone, respectively. Interestingly, a further search through literature revealed that there were more of such cases, in which differentiation between the ortho-/para-orientation had not been carried out correctly in the structure elucidation of naphthalene containing abietane diterpenoids. Therefore, in the current study, we pointed out some 1D and 2D NMR generalizations that would help the unambiguous deduction of the ortho-/para-orientation of naphthalene containing abietanes and revised the structure of some previously described compounds accordingly. Based on these generalizations, structures of sibiriquinones A and B, sahandinone, and sahandone were revised to the known structures 1,2-didehydromiltirone, miltirone, saprorthoquinone, and sahandone B, respectivelyand tebesinone B, arucadiol, and sahandol II were revised to three undescribed structures. It was also proposed that structures of palmitoyl arucadiol and compounds with the salvifolane skeleton need revision. Furthermore, these structure revisions shed light on the structure-activity relationship of the quinone diterpenoids, approving that the ortho-quinone is the critical structural component for cytotoxicity in these compounds.

Fast Screening of Protein Tyrosine Phosphatase 1B Inhibitor from Salvia miltiorrhiza Bge by Cell Display-Based Ligand Fishing

Salvia miltiorrhiza Bge is a medicinal plant (Chinese name "Danshen") widely used for the treatment of hyperglycemia in traditional Chinese medicine. Protein tyrosine phosphatase 1B (PTP1B) has been recognized as a potential target for insulin sensitizing for the treatment of diabetes. In this work, PTP1B was displayed at the surface of E. coli cells (EC-PTP1B) to be used as a bait for fishing of the enzyme's inhibitors present in the aqueous extract of S. miltiorrhiza. Salvianolic acid B, a polyphenolic compound, was fished out by EC-PTP1B, which was found to inhibit PTP1B with an IC₅₀ value of 23.35 µM. The inhibitory mechanism of salvianolic acid B was further investigated by enzyme kinetic experiments and molecular docking, indicating salvianolic acid B was a non-competitive inhibitor for PTP1B (with Ki and Kis values of 31.71 µM and 20.08 µM, respectively) and its binding energy was -7.89 kcal/mol. It is interesting that in the comparative work using a traditional ligand fishing bait of PTP1B-immobilized magnetic nanoparticles (MNPs-PTP1B), no ligands were extracted at all. This study not only discovered a new PTP1B inhibitor from S. miltiorrhiza which is significant to understand the chemical basis for the hypoglycemic activity of this plant, but also indicated the effectiveness of cell display-based ligand fishing in screening of active compounds from complex herbal extracts.

New Molecules of Diterpene Origin with Inhibitory Properties toward α-Glucosidase

The incidence of diabetes mellitus (DM), one of the most common chronic metabolic disorders, has increased dramatically over the past decade and has resulted in higher rates of morbidity and mortality worldwide. The enzyme, α-Glucosidase (α-GLy), is considered a therapeutic target for the treatment of type 2 DM. Herein, we synthesized arylidene, heterocyclic, cyanoetoxy- and propargylated derivatives of quinopimaric acid (levopimaric acid diene adduct with p-benzoquinone) 1-50 and, first, evaluated their ability to inhibit α-GLy. Among the tested compounds, quinopimaric acid 1, 2,3-dihydroquinopimaric acid 8 and its amide and heterocyclic derivatives 9, 30, 33, 39, 44, with IC50 values of 35.57-65.98 μM, emerged as being good inhibitors of α-GLy. Arylidene 1β-hydroxy and 1β,13α-epoxy methyl dihydroquinopimarate derivatives 6, 7, 26-29, thiadiazole 32, 1a,4a-dehydroquinopimaric acid 40 and its indole, nitrile and propargyl hybrids 35-38, 42, 45, 48, and 50 showed excellent inhibitory activities. The most active compounds 38, 45, 48, and 50 displayed IC50 values of 0.15 to 0.68 μM, being 1206 to 266 more active than acarbose (IC50 of 181.02 μM). Kinetic analysis revealed the most active diterpene indole with an alkyne substituent 45 as a competitive inhibitor with Ki of 50.45 μM. Molecular modeling supported this finding and suggested that the indole core plays a key role in the binding. Compound 45 also has favorable pharmacokinetic and safety properties, according to the computational ADMET profiling. The results suggested that quinopimaric acid derivatives should be considered as potential candidates for novel alternative therapies in the treatment of type 2 diabetes.

Molecular Mechanism of Tanshinone against Prostate Cancer

Prostate cancer (PCa) is the most common malignant tumor of the male urinary system in Europe and America. According to the data in the World Cancer Report 2020, the incidence rate of PCa ranks second in the prevalence of male malignant tumors and varies worldwide between regions and population groups. Although early PCa can achieve good therapeutic results after surgical treatment, due to advanced PCa, it can adapt and tolerate androgen castration-related drugs through a variety of mechanisms. For this reason, it is often difficult to achieve effective therapeutic results in the treatment of advanced PCa. Tanshinone is a new fat-soluble phenanthraquinone compound derived from Salvia miltiorrhiza that can play a therapeutic role in different cancers, including PCa. Several studies have shown that Tanshinone can target various molecular pathways of PCa, including the signal transducer and activator of transcription 3 (STAT3) pathway, androgen receptor (AR) pathway, phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway, and mitogen-activated protein kinase (MAPK) pathway, which will affect the release of pro-inflammatory cytokines and affect cell proliferation, apoptosis, tumor metabolism, genomic stability, and tumor drug resistance. Thus, the occurrence and development of PCa cells are inhibited. In this review, we summarized the in vivo and in vitro evidence of Tanshinone against prostate cancer and discussed the effect of Tanshinone on nuclear factor kappa-B (NF-κB), AR, and mTOR. At the same time, we conducted a network pharmacology analysis on the four main components of Tanshinone to further screen the possible targets of Tanshinone against prostate cancer and provide ideas for future research.

A network pharmacology-based study on the quality control markers of antithrombotic herbs: Using Salvia miltiorrhiza - Ligusticum chuanxiong as an example

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza (Danshen, DS), the dried root and rhizome of Salvia miltiorrhiza Bunge and Ligusticum chuanxiong (Chuanxiong, CX), the dried rhizomes of Ligusticum striatum DC are effective in invigorating blood circulation and eliminating stasis which is highly related with cardiovascular disease (CVD).

AIM OF STUDY

The identification of activity-based chemical markers is very important, but the complex mechanism of "multi-component, multi-target, and multi-effect" within traditional Chinese medicine (TCM) poses a great challenge to this work. In this study, we combined network pharmacological prediction with experimental validation of the DS and CX to explore an effective method for discovering quality control (QC) of antithrombotic herbs by clarifying the intermediate layer "module/cluster" between the whole complex system and a single component.

MATERIALS AND METHODS

Based on structural similarity analysis of compound and the thrombosis network published before, we firstly modularized two layers called chemical cluster (CC) network and functional module (FM) network respectively and linked them into one bilayer modularized compound target (BMCT) network. "Two-step" calculation was applied on identifying the significant compounds as the potential QC markers from CC. The in vitro inhibitory activity of selected QC marker compounds on thrombin was evaluated to partially verify their pharmacological activities. HPLC was used to determine contents.

RESULTS

According to the network-based analysis, nine compounds with great importance in the BMCT network were identified as QC markers of DS-CX, including tanshinone I, tanshinone IIA, cryptotanshinone, salvianolic acid B, ferulic acid, salvianolic acid A, rosmarinic acid, chlorogenic acid, and coniferyl ferulate. Enzyme inhibitory test partially verified the activity of tanshinone I and tanshinone IIA. Chemical profiling indicated that the nine marker compounds are the main components in the herbal pair.

CONCLUSIONS

This study identified activity-based QC markers of DS-CX herbal pair and provided a new methodology that can be used in the QC of other herbs, herbal pairs, or formulas.

Phytochemical and biological studies on rare and endangered plants endemic to China. Part XXII. Structurally diverse diterpenoids from the leaves and twigs of the endangered conifer Torreya jackii and their bioactivities

A phytochemical investigation on the MeOH extract of the leaves and twigs of the endangered conifer Torreya jackii Chun led to the isolation and characterization of 21 structurally diverse diterpenoids. Among them, six are previously undescribed, including four abietane-type (torreyins A-D, resp.) and two labdane-type diterpenoids (torreyins E and F). Their structures and absolute configurations were determined by a combination of spectroscopic methods, calculated/experimental electronic circular dichroism (ECD) data, and single-crystal X-ray diffraction analyses. In particular, torreyins A-C are rare 11,12-seco-abietane type diterpenoids possessing a dilactone moiety, and their biosynthetic pathway starting from a co-occurring abietane derivative (i.e., cyrtophyllone B) was briefly proposed. Among the isolates, 7-oxo-dehydroabietic acid and 15-methoxy-7,13-abietadien-18-oic acid showed considerable inhibitory effects against acetyl-coenzyme A carboxylase 1 (ACC1) and protein tyrosine phosphatase 1 B (PTP1B), with IC₅₀ values of 3.1 and 6.8 μM, respectively.

Naringenin and cryptotanshinone shift the immune response towards Th1 and modulate T regulatory cells via JAK2/STAT3 pathway in breast cancer

BACKGROUND

Use of natural products has been proposed as an efficient method in modulation of immune system and treatment of cancers. The aim of this study was to investigate the potential of cryptotanshinone (CPT), naringenin, and their combination in modulating the immune response towards Th1 cells and the involvement of JAK2/STAT3 signaling pathway in these effects.

METHODS

Mouse models of delayed type hypersensitivity (DTH) were produced and treated with naringenin and CPT. The proliferation of spleen cells were assessed by Bromodeoxyuridine (BrdU) assay. Flowcytometry and enzyme-linked immunosorbent assay (ELISA) tests were employed to evaluate subpopulation of T-lymphocytes and the levels of cytokines, respectively. The JAK/STAT signaling pathway was analyzed by Western blotting.

RESULTS

We showed higher DTH, increased lymphocyte proliferation, decreased tumor growth and reduced JAK2/STAT3 phosphorylation in mice treated with naringenin and CPT. Moreover, a significant decline in the production of IL-4 and an upsurge in the production of IFN-γ by splenocytes were observed. Additionally, the population of intra-tumor CD4+CD25+Foxp3+ T cells was significantly lower in naringenin + CPT treated animals than that in controls.

CONCLUSION

Naringenin-CPT combination could exert immunomodulatory effects, suggesting this combination as a novel complementary therapeutic regimen for breast cancer.

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.

Approaches to Decrease Hyperglycemia by Targeting Impaired Hepatic Glucose Homeostasis Using Medicinal Plants

Liver plays a pivotal role in maintaining blood glucose levels through complex processes which involve the disposal, storage, and endogenous production of this carbohydrate. Insulin is the hormone responsible for regulating hepatic glucose production and glucose storage as glycogen, thus abnormalities in its function lead to hyperglycemia in obese or diabetic patients because of higher production rates and lower capacity to store glucose. In this context, two different but complementary therapeutic approaches can be highlighted to avoid the hyperglycemia generated by the hepatic insulin resistance: 1) enhancing insulin function by inhibiting the protein tyrosine phosphatase 1B, one of the main enzymes that disrupt the insulin signal, and 2) direct regulation of key enzymes involved in hepatic glucose production and glycogen synthesis/breakdown. It is recognized that medicinal plants are a valuable source of molecules with special properties and a wide range of scaffolds that can improve hepatic glucose metabolism. Some molecules, especially phenolic compounds and terpenoids, exhibit a powerful inhibitory capacity on protein tyrosine phosphatase 1B and decrease the expression or activity of the key enzymes involved in the gluconeogenic pathway, such as phosphoenolpyruvate carboxykinase or glucose 6-phosphatase. This review shed light on the progress made in the past 7 years in medicinal plants capable of improving hepatic glucose homeostasis through the two proposed approaches. We suggest that Coreopsis tinctoria, Lithocarpus polystachyus, and Panax ginseng can be good candidates for developing herbal medicines or phytomedicines that target inhibition of hepatic glucose output as they can modulate the activity of PTP-1B, the expression of gluconeogenic enzymes, and the glycogen content.

Recent advances in PTP1B signaling in metabolism and cancer

Protein tyrosine phosphorylation is one of the major post-translational modifications in eukaryotic cells and represents a critical regulatory mechanism of a wide variety of signaling pathways. Aberrant protein tyrosine phosphorylation has been linked to various diseases, including metabolic disorders and cancer. Few years ago, protein tyrosine phosphatases (PTPs) were considered as tumor suppressors, able to block the signals emanating from receptor tyrosine kinases. However, recent evidence demonstrates that misregulation of PTPs activity plays a critical role in cancer development and progression. Here, we will focus on PTP1B, an enzyme that has been linked to the development of type 2 diabetes and obesity through the regulation of insulin and leptin signaling, and with a promoting role in the development of different types of cancer through the activation of several pro-survival signaling pathways. In this review, we discuss the molecular aspects that support the crucial role of PTP1B in different cellular processes underlying diabetes, obesity and cancer progression, and its visualization as a promising therapeutic target.

Monoamine Oxidase Inhibition by Major Tanshinones from Salvia miltiorrhiza and Selective Muscarinic Acetylcholine M4 Receptor Antagonism by Tanshinone I

Monoamine oxidases (MAOs) and muscarinic acetylcholine receptors (mAChRs) are considered important therapeutic targets for Parkinson's disease (PD). Lipophilic tanshinones are major phytoconstituents in the dried roots of Salvia miltiorrhiza that have demonstrated neuroprotective effects against dopaminergic neurotoxins and the inhibition of MAO-A. Since MAO-B inhibition is considered an effective therapeutic strategy for PD, we tested the inhibitory activities of three abundant tanshinone congeners against recombinant human MAO (hMAO) isoenzymes through in vitro experiments. In our study, tanshinone I (1) exhibited the highest potency against hMAO-A, followed by tanshinone IIA and cryptotanshinone, with an IC50 less than 10 µM. They also suppressed hMAO-B activity, with an IC50 below 25 µM. Although tanshinones are known to inhibit hMAO-A, their enzyme inhibition mechanism and binding sites have yet to be investigated. Enzyme kinetics and molecular docking studies have revealed the mode of inhibition and interactions of tanshinones during enzyme inhibition. Proteochemometric modeling predicted mAChRs as possible pharmacological targets of 1, and in vitro functional assays confirmed the selective M4 antagonist nature of 1 (56.1% ± 2.40% inhibition of control agonist response at 100 µM). These findings indicate that 1 is a potential therapeutic molecule for managing the motor dysfunction and depression associated with PD.

Antibacterial Mechanism of Dihydrotanshinone I

The antimicrobial activity and the underlying action mechanisms of dihydrotanshinone I against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamases Staphylococcus aureus were investigated with Kleihauer-Betke (K-B) test. The antibacterial mechanisms of dihydrotanshinone I were investigated by monitoring the changes in electric conductivity, concentration of AKP, protein content, and patterns of protein electrophoretic bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The antibacterial rings showed that antimicrobial activity of dihydrotanshinone I at 18 mM was stronger to Staphylococcus aureus than to methicillin-resistant Staphylococcus aureus and extended-spectrum beta-lactamases Staphylococcus aureus. The minimum inhibitory concentration (MIC) and IC50 values showed that dihydrotanshinone I had the strongest inhibitory activity against S. aureus (MIC = 280 µM, IC50 = 874 ± 0.01 µM, respectively). Dihydrotanshinone I could increase the electric conductivity, concentration of alkaline phosphatase (AKP) and protein content. The patterns of protein bands in SDS-PAGE were changed obviously. Dihydrotanshinone I also significantly inhibited S. aureus, methicillin-resistant S. aureus, and extended-spectrum beta-lactamases S. aureus, indicating that dihydrotanshinone I can damage the structures of cell wall and cell membrane to increase permeability of cell membrane and release of cell components. Dihydrotanshinone I could influence the synthesis of bacterial protein, destroy the protein, or reject the anabolism or expression of the protein, and finally lead to the loss of normal physiological function of bacteria.

Expansion within the CYP71D subfamily drives the heterocyclization of tanshinones synthesis in Salvia miltiorrhiza

Tanshinones are the bioactive nor-diterpenoid constituents of the Chinese medicinal herb Danshen (Salvia miltiorrhiza). These groups of chemicals have the characteristic furan D-ring, which differentiates them from the phenolic abietane-type diterpenoids frequently found in the Lamiaceae family. However, how the 14,16-epoxy is formed has not been elucidated. Here, we report an improved genome assembly of Danshen using a highly homozygous genotype. We identify a cytochrome P450 (CYP71D) tandem gene array through gene expansion analysis. We show that CYP71D373 and CYP71D375 catalyze hydroxylation at carbon-16 (C16) and 14,16-ether (hetero)cyclization to form the D-ring, whereas CYP71D411 catalyzes upstream hydroxylation at C20. In addition, we discover a large biosynthetic gene cluster associated with tanshinone production. Collinearity analysis indicates a more specific origin of tanshinones in Salvia genus. It illustrates the evolutionary origin of abietane-type diterpenoids and those with a furan D-ring in Lamiaceae.

Abietane Diterpenes as Potential Candidates for the Management of Type 2 Diabetes

Diabetes mellitus (DM) is considered one of the most common metabolic disorders with an elevated morbidity and mortality rate. It is characterised by a deficiency in insulin secretion or degradation of secreted insulin. Many internal and external factors, such as oxidative stress, obesity and sedentary lifestyle, among others, have been suggested as the major causes of these cell alterations. Diabetes I and II are the most common types of diabetes. Treatment of type I requires insulin injection, while type II can be managed using different synthetic antidiabetic agents. However, their effectiveness is limited as a result of low bioavailability, high cost of drug production, and unfavourable side effects. There is a great need to develop alternative and more active antidiabetic drugs from natural sources. Different forms of natural products have been used since time immemorial as a source of medicine for the purpose of curing numerous human diseases, including diabetes. Secondary metabolites such as polyphenols, flavonoids, terpenoids, alkaloids and several other constituents have direct and indirect roles in controlling such diseases; among them, abietane diterpenes have been reported to display a broad spectrum of promising biological activities including diabetes. This review aimed to summarize existing data from SciFinder (2005-2018) on the biological importance of abietane diterpenes in the prevention and management of type 2 diabetes and closely related diseases.

Phytochemicals as Potential Epidrugs in Type 2 Diabetes Mellitus

Type 2 diabetes Mellitus (T2DM) prevalence has significantly increased worldwide in recent years due to population age, obesity, and modern sedentary lifestyles. The projections estimate that 439 million people will be diabetic in 2030. T2DM is characterized by an impaired β-pancreatic cell function and insulin secretion, hyperglycemia and insulin resistance, and recently the epigenetic regulation of β-pancreatic cells differentiation has been underlined as being involved. It is currently known that several bioactive molecules, widely abundant in plants used as food or infusions, have a key role in histone modification and DNA methylation, and constituted potential epidrugs candidates against T2DM. In this sense, in this review the epigenetic mechanisms involved in T2DM and protein targets are reviewed, with special focus in studies addressing the potential use of phytochemicals as epidrugs that prevent and/or control T2DM in vivo and in vitro. As main findings, and although some controversial results have been found, bioactive molecules with epigenetic regulatory function, appear to be a potential replacement/complementary therapy of pharmacological hypoglycemic drugs, with minimal side effects. Indeed, natural epidrugs have shown to prevent or delay the T2DM development and the morbidity associated to dysfunction of blood vessels, eyes and kidneys due to sustained hyperglycemia in T2DM patients.

Antioxidant and Antidiabetic Activities of Flavonoid Derivatives from the Outer Skins of Allium cepa L

The onion, known as the bulb onion or common onion, is not only a key ingredient in many tasty and healthy vegetarian meals but also many traditional medicines. Nine new flavonoids [cepaflavas A, B (5, 6), cepadials A-D (7-9 and 14), and cepabiflas A-C (10-12)] and six known compounds (1-4, 13, 15) were obtained from the outer skins of Allium cepa L. Among them, compounds 5, 6, and 9 might be artificial products formed during extraction and isolation. New compounds were structurally elucidated using various spectroscopy/spectrometry techniques, including NMR and HRMS, and computational methods. Their absolute configurations were determined using time-dependent density functional theory calculations, combined with ECD spectroscopy, optical rotation calculation, and statistical procedures (CP3 and DP4 analysis). The free radical scavenging assays revealed that the new compounds 10-12 possessed considerable antioxidant activities with IC₅₀ values of 4.25-8.88 and 7.12-8.14 μM against DPPH and ABTS^•+, respectively. Compounds 13-15 showed substantial inhibitory activities against both α-glucosidase and protein tyrosine phosphatase 1B (PTP1B), with IC₅₀ values of 0.89-6.80 and 1.13-6.82 μM, respectively. On the basis of molecular docking studies, 13 and 15 were predicted to have high binding capacity and strong affinity toward the active site of PTP1B.

Protein Tyrosine Phosphatase (PTP1B): A promising Drug Target Against Life-threatening Ailments

Background:

Protein tyrosine phosphatases are enzymes which help in the signal transduction in diabetes, obesity, cancer, liver diseases and neurodegenerative diseases. PTP1B is the main member of this enzyme from the protein extract of human placenta. In phosphate inhibitors development, significant progress has been made over the last 10 years. In early-stage clinical trials, few compounds have reached whereas in the later stage trials or registration, yet none have progressed. Many researchers investigate different ways to improve the pharmacological properties of PTP1B inhibitors.

Objective:

In the present review, authors have summarized various aspects related to the involvement of PTP1B in various types of signal transduction mechanisms and its prominent role in various diseases like cancer, liver diseases and diabetes mellitus.

Conclusion:

There are still certain challenges for the selection of PTP1B as a drug target. Therefore, continuous future efforts are required to explore this target for the development of PTP inhibitors to treat the prevailing diseases associated with it.

Pharmacological activities of dihydrotanshinone I, a natural product from Salvia miltiorrhiza Bunge

Salvia miltiorrhiza Bunge (Danshen), a famous traditional Chinese herb, has been used clinically for the treatment of various diseases for centuries. Document data showed that tanshinones, a class of lipophilic abietane diterpenes rich in this herb, possess multiple biological effects in vitro and in vivo models. Among which, 15,16-dihydrotanshinone I (DHT) has received much attention in recent years. In this systematical review, we carefully selected, analyzed, and summarized high-quality publications related to pharmacological effects and the underlying mechanisms of DHT. DHT has anti-cancer, cardiovascular protective, anti-inflammation, anti-Alzheimer's disease, and other effects. Furthermore, several molecules such as hypoxia-inducible factor (HIF-1α), human antigen R (HuR), acetylcholinesterase (AchE), etc. have been identified as the potential targets for DHT. The diverse pharmacological activities of DHT provide scientific evidence for the local and traditional uses of Salvia miltiorrhiza Bunge. We concluded that DHT might serve as a lead compound for drug discovery in related diseases while further in-depth investigations are still needed.

Chalcone derivatives from the root bark of Morus alba L. act as inhibitors of PTP1B and α-glucosidase

As part of our continuing research to obtain pharmacologically active compounds from Morus alba L. (Moraceae), four Diels-Alder type adducts (DAs) [morusalbins A-D], one isoprenylated flavonoid [albanin T], together with twenty-one known phenolic compounds were isolated from its root bark. The chemical structures were established using NMR, MS, and ECD spectra. The DAs including morusalbins A-D, albasin B, macrourin G, yunanensin A, mulberrofuran G and K, and albanol B exhibited strong inhibitory activities against both protein tyrosine phosphatase 1B (PTP1B) (IC₅₀, 1.90-9.67 μM) and α-glucosidase (IC₅₀, 2.29-5.91 μM). In the kinetic study, morusalbin D, albasin B, and macrourin G showed noncompetitive PTP1B inhibition, with K_i values of 0.33, 1.00, and 1.09 μM, respectively. In contrast, these DAs together with yunanensin A produced competitive inhibition of α-glucosidase, with K_i values of 0.64, 0.42, 2.42, and 1.19 μM, respectively. Furthermore, molecular docking studies revealed that these active DAs have high affinity and tight binding capacity towards the active site of PTP1B and α-glucosidase.

Computational insights into β-site amyloid precursor protein enzyme 1 (BACE1) inhibition by tanshinones and salvianolic acids from Salvia miltiorrhiza via molecular docking simulations

The rhizome of Salvia miltiorrhiza has emerged as a rich source of natural therapeutic agents, and its several compounds are supposed to exhibit favorable effects on Alzheimer's disease (AD). The present work investigate the anti-AD potentials of 12 tanshinones, three salvianolic acids and three caffeic acid derivatives from S. miltiorrhiza via the inhibition of β-site amyloid precursor protein cleaving enzyme 1 (BACE1). Among the tested compounds, deoxyneocryptotanshinone (1), salvianolic acid A (13) and salvianolic acid C (15) displayed good inhibitory effect on BACE1 with IC₅₀ values of 11.53 ± 1.13, 13.01 ± 0.32 and 9.18 ± 0.03 μM, respectively. Besides this, enzyme kinetic analysis on BACE1 revealed 13, a competitive type inhibitor while 1 and 15 showed mixed-type inhibition. Furthermore, molecular docking simulation displayed negative binding energies (AutoDock 4.2.6 = -10.0 to -7.1 kcal/mol) of 1, 13, and 15 for BACE1, indicating these compounds bound tightly to the active site of the enzyme with low energy and high affinity. The results of the present study clearly demonstrate that S. miltiorrhiza and its constituents have potential anti-AD activity and can be used as a therapeutic agent for the treatment of AD.