Chemical Constituents of Euonymus alatus (Thunb.) Sieb. and Their PTP1B and α-Glucosidase Inhibitory Activities

Aloe juvenna Brandham & S.Carter as α-Amylase Inhibitor and Hypoglycaemic Agent with Anti-inflammatory Properties for Diabetes Management

Despite Aloe's traditional use, Aloe juvenna Brandham & S.Carter is poorly characterized. Other Aloes are known for their antidiabetic activity. This study describes the antidiabetic potentials and phytoconstituents of the A. juvenna leaves methanolic extract (AJME). Twenty-six phytoconstituents of AJME were described using HPLC/MS-MS. Lupeol and vitexin were isolated using column chromatography. The antidiabetic activity of AJME was investigated using an in vivo high-fat diet/streptozotocin-induced diabetic rat model and in vitro α-glucosidase and α-amylase inhibitory activity assays. AJME demonstrated its α-amylase inhibitory activity (IC50=313±39.9 ppm) with no effect on α-glucosidase. In vivo, AJME dose-dependently improved hyperglycaemia in a high-fat diet/streptozotocin-induced diabetic rat model. Notably, the higher dose (1600 mg/kg) of AJME significantly downregulated serum interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-1 genes, suggesting its anti-inflammatory effect. These findings indicate AJME's potential as a significant antidiabetic agent through its α-amylase inhibition, hypoglycaemic, and anti-inflammatory properties.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA .

Euonymus alatus (Thunb.) Siebold Prevents Osteoclast Differentiation and Osteoporosis

Euonymus alatus (Thunb.) Siebold, a traditional medicinal plant, has been used in China and several other Asian countries to address a variety of health concerns. The extensive research conducted on E. alatus is driven by its diverse pharmacological applications. However, its biological effects on osteoclastogenesis and osteoporosis have not been previously studied. In this research, we investigated the impact of an ethanolic extract of E. alatus (EEEA) on osteoclast differentiation and function as well as estrogen deficiency-induced bone loss. We found that EEEA inhibits osteoclast differentiation by downregulating the expression of the receptor activator of nuclear factor-κB ligand (RANKL) in osteoclast-supporting cells and by directly impeding RANKL-mediated signaling pathways for osteoclastogenesis in precursor cells. In addition, EEEA inhibited the bone-resorptive function of mature osteoclasts in vitro. Furthermore, oral administration of EEEA significantly alleviated bone loss in an ovariectomy-induced osteoporosis mouse model. Additionally, we identified phytochemicals in EEEA that have suppressive effects on osteoclast differentiation and bone loss. Collectively, these results suggest that EEEA holds potential as a biotherapeutic candidate for anti-postmenopausal osteoporosis.

Natural products targeting inflammation-related metabolic disorders: A comprehensive review

Currently, the incidence of metabolic disorders is increasing, setting a challenge to global health. With major advancement in the diagnostic tools and clinical procedures, much has been known in the etiology of metabolic disorders and their corresponding pathophysiologies. In addition, the use of in vitro and in vivo experimental models prior to clinical studies has promoted numerous biomedical breakthroughs, including in the discovery and development of drug candidates to treat metabolic disorders. Indeed, chemicals isolated from natural products have been extensively studied as prospective drug candidates to manage diabetes, obesity, heart-related diseases, and cancer, partly due to their antioxidant and anti-inflammatory properties. Continuous efforts have been made in parallel to improve their bioactivity and bioavailability using selected drug delivery approaches. Here, we provide insights on recent progress in the role of inflammatory-mediated responses on the initiation of metabolic disorders, with particular reference to diabetes mellitus, obesity, heart-related diseases, and cancer. In addition, we discussed the prospective role of natural products in the management of diabetes, obesity, heart-related diseases, and cancers and provide lists of potential biological targets for high throughput screening in drug discovery and development. Lastly, we discussed findings observed in the preclinical and clinical studies prior to identifying suitable approaches on the phytochemical drug delivery systems that are potential to be used in the treatment of metabolic disorders.

Natural α-Glucosidase and Protein Tyrosine Phosphatase 1B Inhibitors: A Source of Scaffold Molecules for Synthesis of New Multitarget Antidiabetic Drugs

Diabetes mellitus (DM) represents a group of metabolic disorders that leads to acute and long-term serious complications and is considered a worldwide sanitary emergence. Type 2 diabetes (T2D) represents about 90% of all cases of diabetes, and even if several drugs are actually available for its treatment, in the long term, they show limited effectiveness. Most traditional drugs are designed to act on a specific biological target, but the complexity of the current pathologies has demonstrated that molecules hitting more than one target may be safer and more effective. The purpose of this review is to shed light on the natural compounds known as α-glucosidase and Protein Tyrosine Phosphatase 1B (PTP1B) dual-inhibitors that could be used as lead compounds to generate new multitarget antidiabetic drugs for treatment of T2D.

A comprehensive review on the antidiabetic activity of flavonoids targeting PTP1B and DPP-4: a structure-activity relationship analysis

Type 2 diabetes (T2D) is an expanding global health problem, resulting from defects in insulin secretion and/or insulin resistance. In the past few years, both protein tyrosine phosphatase 1B (PTP1B) and dipeptidyl peptidase-4 (DPP-4), as well as their role in T2D, have attracted the attention of the scientific community. PTP1B plays an important role in insulin resistance and is currently one of the most promising targets for the treatment of T2D, since no available PTP1B inhibitors were still approved. DPP-4 inhibitors are among the most recent agents used in the treatment of T2D (although its use has been associated with possible cardiovascular adverse events). The antidiabetic properties of flavonoids are well-recognized, and include inhibitory effects on the above enzymes, although hitherto not therapeutically explored. In the present study, a comprehensive review of the literature of both synthetic and natural isolated flavonoids as inhibitors of PTP1B and DPP-4 activities is made, including their type of inhibition and experimental conditions, and structure-activity relationship, covering a total of 351 compounds. We intend to provide the most favorable chemical features of flavonoids for the inhibition of PTP1B and DPP-4, gathering information for the future development of compounds with improved potential as T2D therapeutic agents.

Traditional uses, botany, phytochemistry, pharmacology, separation and analysis technologies of Euonymus alatus (Thunb.) Siebold: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Euonymus alatus (Thunb.) Siebold (E. alatus), a well-known medicinal plant, has been widely used thousands of years in China for the treatment of various diseases such as urticaria, dysmenorrhea, wound, dysentery, blood stasis, rheumatism and arthritis. Due to the extensive application of E. alatus in the fields of ethnopharmacological usage, the pharmaceutical researches of E. alatus keeps deepening.

AIM OF THE STUDY

This paper reviewed and summarized the integrated research progress of this medicinal plant. A comprehensive summary and comparison of traditional usages, botany, phytochemistry, pharmacology, toxicology, separation and analysis technologies of the E. alatus highlight recent scientific advances, which provides new insights into the research and development of this medicinal plant and would be helpful to promote the research situation of underlying pharmacological mechanisms and further utilizations of E. alatus.

MATERIAL AND METHODS

Literature survey was carried out via classic books of herbal medicine, PhD. and MSc. Dissertations. Online scientific databases including Pubmed, SciFinder, Science Direct, Scopus, the Web of Science, Google Scholar, China National Knowledge Infrastructure (CNKI) and others were searched up to February 2020 to identify eligible studies. All literatures of the research subject are analyzed and summarized in this review.

RESULTS

The E. alatus has been widely used in traditional practice in China, Korea and other Asian Countries. In the study of phytochemistry, more than 230 chemical constituents have been isolated and identified from E. alatus, including sesquiterpenoids, diterpenoids, triterpenoids, flavonoids, phenylpropanoids, lignans, steroids, alkaloids and other compounds. Among them, literature reports show that flavonoids and steroids are the most important bioactive substances found in this plant. A number of researches also have shown that extracts and compounds from E. alatus exert a wide spectrum of pharmacological effects, including antidiabetic effect, anti-tumor effects, anti-inflammatory effects, hepatoprotective effects, antioxidant effects, antibacterial effects, as well as other effects. However, most of the studies without clinical research. Research into plant's toxicological effects has also been limited. In addition, this review also summarizes and compares the separation and analysis technologies of E. alatus.

CONCLUSIONS

E. alatus has potential for the treatment of many diseases, especially tumors and diabetes. But many traditional uses of E. alatus have not been validated by current investigations. Additionally, modern studies haven't gone far enough into its pharmacological effects and the corresponding chemical constituents, more efforts should be made to illuminate the underlying mechanisms of E. alatus for treatment of tumors and diabetes. Moreover, the toxicological effects of this plant can be further studied. Currently, there are limited studies on its side effects and toxicological effects, which should provide further guidance for the safety of clinical use.

Neuroprotective Effects of Euonymus alatus Extract on Scopolamine-Induced Memory Deficits in Mice

Euonymus alatus is considered to elicit various beneficial effects against cancer, hyperglycemia, menstrual discomfort, diabetic complications, and detoxification. The young leaves of this plant are exploited as food and also utilized for traditional medicine in East Asian countries, including Korea and China. Our preliminary study demonstrated that ethanolic extract from the Euonymus alatus leaf (EAE) exhibited the strongest antioxidant enzyme-inducing activity among more than 100 kinds of edible tree leaf extracts. This study investigated whether EAE could attenuate the cognitive deficits caused by oxidative stress in mice. Oral intubation of EAE at 100 mg/kg bw or higher resulted in significant improvements to the memory and behavioral impairment induced via i.p. injection of scopolamine. Furthermore, EAE enhanced the expression levels of hippocampal neurotrophic factors such as brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor in mice, activated the Nrf2, and the downstream heme oxygenase-1 (HO-1) a quintessential antioxidant enzyme. As rutin (quercetin-3-O-rutinose) was abundantly present in EAE and free quercetin was able to induce defensive antioxidant enzymes in an Nrf2-dependent manner, our findings suggested that quercetin derived from rutin via the intestinal microflora played a significant role in the protection of the mouse hippocampus from scopolamine-induced damage through BDNF-mediated Nrf2 activation, thereby dampening cognitive decline.

Natural allosteric modulators and their biological targets: molecular signatures and mechanisms

Covering: 2008 to 2018Over the last decade more than two hundred single natural products were confirmed as natural allosteric modulators (alloNPs) of proteins. The compounds are presented and discussed with the support of a chemical space, constructed using a principal component analysis (PCA) of molecular descriptors from chemical compounds of distinct databases. This analysis showed that alloNPs are dispersed throughout the majority of the chemical space defined by natural products in general. Moreover, a cluster of alloNPs was shown to occupy a region almost devoid of allosteric modulators retrieved from a dataset composed mainly of synthetic compounds, further highlighting the importance to explore the entire natural chemical space for probing allosteric mechanisms. The protein targets which alloNPs bind to comprised 81 different proteins, which were classified into 5 major groups, with enzymes, in particular hydrolases, being the main representative group. The review also brings a critical interpretation on the mechanisms by which alloNPs display their molecular action on proteins. In the latter analysis, alloNPs were classified according to their final effect on the target protein, resulting in 3 major categories: (i) local alteration of the orthosteric site; (ii) global alteration in protein dynamics that change function; and (iii) oligomer stabilisation or protein complex destabilisation via protein-protein interaction in sites distant from the orthosteric site. G-protein coupled receptors (GPCRs), which use a combination of the three types of allosteric regulation found, were also probed by natural products. In summary, the natural allosteric modulators reviewed herein emphasise their importance for exploring alternative chemotherapeutic strategies, potentially pushing the boundaries of the druggable space of pharmacologically relevant drug targets.

Efficacy and safety of Shenmayizhi decoction as an adjuvant treatment for vascular dementia: Study protocol for a randomized controlled trial

BACKGROUND

Vascular dementia (VaD) is the second most common cause of dementia. The treatment of VaD still remains a challenge so far. Traditional Chinese Herbal medicine is a promising therapy due to their multiple components and targets. Shenmayizhi decoction (SMYZD), a Chinese Herbal prescription, has been reported its effective in alleviating cognitive dysfunction in clinical practice. However, strong clinical research of SMYZD in the treatment of VaD was lack. Therefore, we design this study to evaluate the adjuvant role of SMYZD in the treatment of VaD.

METHODS

This is a multicenter, randomized, blind, controlled trial. A total of 196 eligible patients will be assigned to receive Ginkgo biloba extracts (GBEs) plus SMYZD granule or GBEs plus SMYZD mimetic granule in a 1:1 ratio. The duration of the trial will be 12 weeks, and a follow-up will be performed at the 24th week. The primary outcomes are the National Institute of Health stroke scale (NIHSS) and the Alzheimer Disease Assessment Scale-cognitive subscale (ADAS-cog). The secondary outcomes include the Mini-Mental State Examination (MMSE), the traditional Chinese Medicine (TCM) syndrome scale, Activities of Daily Living (ADL), concentrations of hypersensitive C-reactive protein (Hs-CRP), neuron-specific enolase (NSE) and homocysteine (HCY) in serum. Researchers will record any adverse events throughout the trial.

DISCUSSION

This study will provide evidences to evaluate the efficacy and safety of SMYZD in combination with GBEs in treatment of VaD, as well as the adjuvant role of SMYZD in combination.

TRIAL IS REGISTERED AT CHINESE CLINICAL TRIAL REGISTRY

ChiCTR1800017359.

(3β,16α)-3,16-Dihydroxypregn-5-en-20-one from the Twigs of Euonymus alatus (Thunb.) Sieb. Exerts Anti-Inflammatory Effects in LPS-Stimulated RAW-264.7 Macrophages

To discover new pharmacologically active natural products, here, we performed the phytochemical analysis of a Korean medicinal plant. Euonymus alatus (Thunb.) Sieb. is a traditional medicinal plant that has been used as a remedy for various diseases in Asian countries. In particular, the cork cambium on the twigs of E. alatus has been used to treat dysmenorrhea, tumors, diabetes, and wound. Phytochemical analysis of the methanolic extract of E. alatus twigs led to the isolation of a sterol, which was identified as (3β,16α)-3,16-dihydroxypregn-5-en-20-one (1) by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and high-resolution electrospray ionization mass spectrometry. The stereochemistry of 1 was established with nuclear Overhauser effect spectroscopy (NOESY) analysis and comparison of electronic circular dichroism (ECD) data. To the best of our knowledge, the isolation of compound 1 from nature is first reported here, as well as the complete and revised NMR data assignment of 1. In lipopolysaccharide (LPS)-stimulated RAW-264.7 macrophages, compound 1 significantly inhibited nitric oxide (NO) production at an IC₅₀ value of 12.54 ± 0.05 μM as well as the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, the pre-treatment with compound 1 attenuated the LPS-induced phosphorylation of nuclear factor kappa B (NF-κB) p65 through the inhibition of the phosphorylation of IκB kinase alpha (IKKα), IKKβ, and inhibitor of kappa B alpha (IκBα). Compound 1 also inhibited the LPS-induced phosphorylation of p38, c-Jun NH₂-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). Taken together, compound 1 may serve as an anti-inflammatory constituent of E. alatus twigs and its anti-inflammatory property is thought to be associated with the inhibition of NO production via suppression of iNOS and COX-2 expression through inhibition of IKKα/β, I-κBα and NF-κB p65 activation and downregulation of p38, JNK, and ERK mitogen-activated protein kinase signal pathways in RAW 264.7 macrophages. These findings also provide experimental evidence that compound 1 identified from E. alatus twigs could be a candidate for an anti-inflammatory agent.

Protective effect of Epicatechin on APAP-induced acute liver injury of mice through anti-inflammation and apoptosis inhibition

Epicatechin (EC) is the most effective compound in Euonymus alatus (Thunb.)Sieb, and possesses a series of benefits, including anti-inflammatory, antioxidant, antiobesity and anticancer effects. In this study, we investigated the protective effects of EC in Acetaminophen(N-acetyl-p-aminophenol, APAP)-induced acute liver injury in C57BL/6J mice and explored the possible mechanisms involved in these effects.[Formula: see text].

Anti-Diabetic Effects of Acankoreagenin from the Leaves of Acanthopanax Gracilistylus Herb in RIN-m5F Cells via Suppression of NF-κB Activation

Diabetes mellitus is a chronic degenerative disease that causes long-term complications and represents a serious public health problem. In this manuscript, acankoreagenin isolated from the leaves of Acanthopanax gracilistylus (LAG) is thought to possess excellent anti-diabetic properties. In vitro, anti-diabetic activities were assessed based on the inhibitory activities with α-glucosidase (IC₅₀ 13.01 μM), α-amylase (IC₅₀ 30.81 μM), and PTP1B (IC₅₀ 16.39 μM). Acankoreagenin showed better anti-diabetic effects. Then, an investigation was performed to analyze the insulin secretion effects of the insulin-secreting cell line in RIN-m5F cells. It was found that acankoreagenin could increase the insulin release in RIN-m5F cells. It was also found that acankoreagenin reduced NO production, activity of caspase-3, and the reactive oxygen species levels in the cells injured by processing of cytokines. In western blotting, inactivation of NF-κB signaling was confirmed. Acankoreagenin (20 μM) showed a higher I-κBα expression and lower NF-κB expression than the control group and showed a better expression than the positive control L-NAME (1 mM) (p < 0.05). This study demonstrates the anti-diabetic effects of acankoreagenin in vitro and suggests acankoreagenin might offer therapeutic potential for treating diabetes mellitus.

Protein tyrosine phosphatase 1B inhibitors from natural sources

Since PTP1B enzyme was discovered in 1988, it has captured the research community's attention. This landmark discovery has stimulated numerous research studies on a variety of human diseases, including cancer, inflammation, and diabetes. Tremendous progress has been made in finding PTP1B inhibitors and exploring PTP1B regulatory mechanisms. This review investigates for the natural PTP1B inhibitors, and focuses on the common characteristics of the discovered structures and structure-activity relationships. To facilitate understanding, all the natural compounds are here divided into five different classes (fatty acids, phenolics, terpenoids, steroids, and alkaloids), according to their skeletons. These PTP1B inhibitors of scaffold structures could serve as a theoretical basis for new concept drug discovery and design.

α-Methyl artoflavanocoumarin from Juniperus chinensis exerts anti-diabetic effects by inhibiting PTP1B and activating the PI3K/Akt signaling pathway in insulin-resistant HepG2 cells

Diabetes mellitus is one of the greatest global health issues and much research effort continues to be directed toward identifying novel therapeutic agents. Insulin resistance is a challenging integrally related topic and molecules capable of overcoming it are of considerable therapeutic interest in the context of type 2 diabetes mellitus (T2DM). Protein tyrosine phosphatase 1B (PTP1B) negatively regulates insulin signaling transduction and is regarded a novel therapeutic target in T2DM. Here, we investigated the inhibitory effect of α-methyl artoflavanocoumarin (MAFC), a natural flavanocoumarin isolated from Juniperus chinensis, on PTP1B in insulin-resistant HepG2 cells. MAFC was found to potently inhibit PTP1B with an IC₅₀ of 25.27 ± 0.14 µM, and a kinetics study revealed MAFC is a mixed type PTP1B inhibitor with a K _i value of 13.84 µM. Molecular docking simulations demonstrated MAFC can bind to catalytic and allosteric sites of PTP1B. Furthermore, MAFC significantly increased glucose uptake and decreased the expression of PTP1B in insulin-resistant HepG2 cells, down-regulated the phosphorylation of insulin receptor substrate (IRS)-1 (Ser307), and dose-dependently enhanced the protein levels of IRS-1, phosphorylated phosphoinositide 3-kinase (PI3K), Akt, and ERK1. These results suggest that MAFC from J. chinensis has therapeutic potential in T2DM by inhibiting PTP1B and activating insulin signaling pathways.

Camellianols A-G, Barrigenol-like Triterpenoids with PTP1B Inhibitory Effects from the Endangered Ornamental Plant Camellia crapnelliana

Seven new naturally occurring barrigenol-like compounds, camellianols A-G (1-7), and 10 known triterpenoids were isolated from the twigs and leaves of the cultivated endangered ornamental plant Camellia crapnelliana. According to the ECD octant rule for saturated cyclohexanones, the absolute configurations of camellianols D (4) and E (5) were defined. The backbones of the remaining new isolates are assumed to have the same absolute configuration as compounds 4, 5, and harpullone (12). Compounds 2, 3, 9, 10, 13, and 16 exhibited inhibitory effects on the protein tyrosine phosphatase 1B (PTP1B) enzyme, with IC₅₀ values less than 10 μM.

Structure-related protein tyrosine phosphatase 1B inhibition by naringenin derivatives

Naturally occurring flavonoids co-exist as glycoside conjugates, which dominate aglycones in their content. To unveil the structure-activity relationship of a naturally occurring flavonoid, we investigated the effects of the glycosylation of naringenin on the inhibition of enzyme systems related to diabetes (protein tyrosine phosphatase 1B (PTP1B) and α-glycosidase) and on glucose uptake in the insulin-resistant state. Among the tested naringenin derivatives, prunin, a single-glucose-containing flavanone glycoside, potently inhibited PTP1B with an IC₅₀ value of 17.5±2.6µM. Naringenin, which lacks a sugar molecule, was the weakest inhibitor compared to the reference compound, ursolic acid (IC₅₀: 5.4±0.30µM). In addition, prunin significantly enhanced glucose uptake in a dose-dependent manner in insulin-resistant HepG2 cells. Regarding the inhibition of α-glucosidase, naringenin exhibited more potent inhibitory activity (IC₅₀: 10.6±0.49µM) than its glycosylated forms and the reference inhibitor, acarbose (IC₅₀: 178.0±0.27µM). Among the glycosides, only prunin (IC₅₀: 106.5±4.1µM) was more potent than the positive control. A molecular docking study revealed that prunin had lower binding energy and higher binding affinity than glycosides with higher numbers of H-bonds, suggesting that prunin is the best fit to the PTP1B active site cavity. Therefore, in addition to the number of H-bonds present, possible factors affecting the protein binding and PTP1B inhibition of flavanones include their fit to the active site, hydrogen-bonding affinity, Van der Waals interactions, H-bond distance, and H-bond stability. Furthermore, this study clearly depicted the association of the intensity of bioactivity with the arrangement and characterization of the sugar moiety on the flavonoid skeleton.

Euonymus alatus: A Review on Its Phytochemistry and Antidiabetic Activity

Euonymus alatus (E. alatus) is a medicinal plant used in some Asian countries for treating various conditions including cancer, hyperglycemia, and diabetic complications. This review outlines the phytochemistry and bioactivities of E. alatus related to antidiabetic actions. More than 100 chemical constituents have been isolated and identified from E. alatus, including flavonoids, terpenoids, steroids, lignans, cardenolides, phenolic acids, and alkaloids. Studies in vitro and in vivo have demonstrated the hypoglycemic activity of E. alatus extracts and its certain constituents. The hypoglycemic activity of E. alatus may be related to regulation of insulin signaling and insulin sensitivity, involving PPARγ and aldose reductase pathways. Further studies on E. alatus and its bioactive compounds may help to develop new agents for treating diabetes and diabetic complications.