Recent advances in the development of sesquiterpenoids in the treatment of type 2 diabetes

Identification of promising dipeptidyl peptidase-4 and protein tyrosine phosphatase 1B inhibitors from selected terpenoids through molecular modeling

Motivation

Investigating novel drug-target interactions is crucial for expanding the chemical space of emerging therapeutic targets in human diseases. Herein, we explored the interactions of dipeptidyl peptidase-4 and protein tyrosine phosphatase 1B with selected terpenoids from African antidiabetic plants.

Results

Using molecular docking, molecular dynamics simulations, molecular mechanics with generalized Born and surface area solvation-free energy, and density functional theory analyses, the study revealed dipeptidyl peptidase-4 as a promising target. Cucurbitacin B, 6-oxoisoiguesterin, and 20-epi-isoiguesterinol were identified as potential dipeptidyl peptidase-4 inhibitors with strong binding affinities. These triterpenoids interacted with key catalytic and hydrophobic pockets of dipeptidyl peptidase-4, demonstrating structural stability and flexibility under dynamic conditions, as indicated by dynamics simulation parameters. The free energy analysis further supported the binding affinities in dynamic environments. Quantum mechanical calculations revealed favorable highest occupied molecular orbital and lowest unoccupied molecular orbital energy profiles, indicating the suitability of the hits as proton donors and acceptors, which likely enhance their molecular interactions with the targets. Moreover, the terpenoids showed desirable drug-like properties, suggesting their potential as safe and effective dipeptidyl peptidase-4 inhibitors. These findings may pave the way for the development of novel antidiabetic agents and nutraceuticals based on these promising in silico hits.

Availability and implementation

Not applicable.

Therapeutic Potential of Rare Sesterterpenoids from Aspergillus Variecolor Strain SDG and Docking Studies

Ethyl acetate extract of the cultures of the soil-derived filamentous fungus, Aspergillus variecolor SDG strain from Nallamala forest resulted in the isolation of extremely rare sesterterpenoids, stellatic acid (1) and andilesin C (2). We report a thorough chemical characterization of these compounds using various spectroscopic techniques and evaluation of their in vitro preclinical therapeutic potential. Stellatic acid exhibits potent antioxidant activity with an IC50 of 38 μg/mL and significant anticancer activity against HeLa, HepG2, MCF7, and A549 cancer cell lines with an IC50 of 7-12 μM. On the other hand, andilesin C displayed moderate cytotoxicity against DU145 and B16F10 cancer cell lines but lacked antioxidant activity. Furthermore, the potential hypoglycemic property of stellatic acid was evaluated by measuring its inhibitory effect against α-glucosidase. It exhibited tenfold potency against yeast α-glucosidase (IC50 101.73 μg/mL) than mammalian α-glucosidase (IC50 1000.00 μg/mL). Docking studies were also performed to suggest the interaction mode of stellatic acid in the α-glucosidase enzyme active site. Notably, yeast α-glucosidase shows a higher affinity towards stellatic acid than mammalian α-glucosidase (3TOP). Thus, the in vitro preclinical study of stellatic acid suggests its potential efficacy in therapeutic drug development.

The Mediterranean Species Calendula officinalis and Foeniculum vulgare as Valuable Source of Bioactive Compounds

Research studies on plant secondary metabolites have increased over the last decades as a consequence of the growing consumer demand for natural products in pharmaceutics and therapeutics, as well as in perfumery and cosmetics. In this perspective, many Mediterranean plant species could be an appreciated source of bioactive compounds with pharmacological and health-promoting properties, including antioxidant, antimicrobial, antiviral, anti-inflammatory, and antitumor ones. Calendula officinalis and Foeniculum vulgare are commercially important plants of the Mediterranean flora, with great therapeutic use in the treatment of many disorders since ancient times, and are now listed in several world pharmacopoeias and drug agencies. The present review offers an overview of the main phytochemicals, phenols, terpenes, and alkaloids, biosynthesized in C. officinalis and F. vulgare, both species endemic to the Mediterranean region. Further, all current knowledge and scientific data on taxonomic classification, botanical description, traditional uses, pharmacological studies, and potential toxicity of both species were reported. The principal aim of this review is to point out the prospective use of C. officinalis and F. vulgare as valuable reservoirs of beneficial plant-derived products with interesting biological properties, also providing suggestions and future challenges for the full exploitation of these two Mediterranean species for human life improvement.

Microencapsulation of Tecoma stans Extracts: Bioactive Properties Preservation and Physical Characterization Analysis

Bioactive compounds from medicinal plants have applications in the development of functional foods. However, since they are unstable, encapsulation is used as a conservation alternative. This work aimed to assess the bioactive properties (antioxidant and hypoglycemic) of different extracts, including the infusion, as well as their spray-dried microencapsulates from Tecoma stans leaves. A factorial design was proposed to determine the best extraction conditions, based on ABTS and DPPH inhibition. Maltodextrin (MD), arabic gum (AG), and a 1:1 blend (MD:AG) were used as encapsulating agents. Moreover, characterization through physicochemical properties, gas chromatography/mass spectrometry (GC-MS) and scanning electron microscopy (SEM) of the best two powders based on the bioactive properties were analyzed. The results showed that the combination of stirring, water, and 5 min provided the highest inhibition to ABTS and DPPH (35.64 ± 1.25 mg Trolox/g d.s. and 2.77 ± 0.01 g Trolox/g d.s., respectively). Spray drying decreased the antioxidant activity of the extract while preserving it in the infusion. The encapsulated infusion with MD:AG had the highest hypoglycemic activity as it presented the lowest glycemic index (GI = 47). According to the results, the microencapsulates could potentially be added in foods to enhance nutritional quality and prevent/treat ailments.

Jianpi Gushen Huayu decoction ameliorated diabetic nephropathy through modulating metabolites in kidney, and inhibiting TLR4/NF-κB/NLRP3 and JNK/P38 pathways

BACKGROUND

Jianpi Gushen Huayu Decoction (JPGS) has been used to clinically treat diabetic nephropathy (DN) for many years. However, the protective mechanism of JPGS in treating DN remains unclear.

AIM

To evaluate the therapeutic effects and the possible mechanism of JPGS on DN.

METHODS

We first evaluated the therapeutic potential of JPGS on a DN mouse model. We then investigated the effect of JPGS on the renal metabolite levels of DN mice using non-targeted metabolomics. Furthermore, we examined the effects of JPGS on c-Jun N-terminal kinase (JNK)/P38-mediated apoptosis and the inflammatory responses mediated by toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB)/NOD-like receptor family pyrin domain containing 3 (NLRP3).

RESULTS

The ameliorative effects of JPGS on DN mice included the alleviation of renal injury and the control of inflammation and oxidative stress. Untargeted metabolomic analysis revealed that JPGS altered the metabolites of the kidneys in DN mice. A total of 51 differential metabolites were screened. Pathway analysis results indicated that nine pathways significantly changed between the control and model groups, while six pathways significantly altered between the model and JPGS groups. Pathways related to cysteine and methionine metabolism; alanine, tryptophan metabolism; aspartate and glutamate metabolism; and riboflavin metabolism were identified as the key pathways through which JPGS affects DN. Further experimental validation showed that JPGS treatment reduced the expression of TLR4/NF-κB/NLRP3 pathways and JNK/P38 pathway-mediated apoptosis related factors.

CONCLUSION

JPGS could markedly treat mice with streptozotocin (STZ)-induced DN, which is possibly related to the regulation of several metabolic pathways found in kidneys. Furthermore, JPGS could improve kidney inflammatory responses and ameliorate kidney injuries in DN mice via the TLR4/NF-κB/NLRP3 pathway and inhibit JNK/P38 pathway-mediated apoptosis in DN mice.

Targeting Retinol-Binding Protein 4 (RBP4) in the Management of Cardiometabolic Diseases

The ancient use of herbs for the treatment of various human diseases have been documented, with several scientific literatures supporting the use of medicinal plants. There is however a major concern about the phyto-constituents in the plants that performs the healing function and the mechanism by which it works for different ailments are still a research prospect. Cardiometabolic disease (CMD) is no doubt becoming more frequent globally and this is due to poor approach in therapy, contrary effects linked with intensive control, inept strategies with old drugs, inadequate control of some risk factors and lack of knowledge of the pathophysiological mechanisms that lead to this malaise. Retinol-binding protein 4 (RBP4) are predominantly secreted in the liver and adipose tissues and several researches have observed that elevation in serum levels of RBP4 often observed in obese experimental animals and human subjects causes CMD (obesity, insulin resistance, hyperlipidemia, etc.). RBP4 has gained special attention in the last 20 years in the field of metabolism research. This review aims to show research interaction of some medicinal plants targeting RBP4 in treating CMD and to encourage researchers, who are interested in CMD drug design, to focus on medicinal plants that inhibit the secretion of serum RBP4 in the adipose tissue for therapeutic approach to CMD. It also aims to identify the major bioactive compounds of plants that serves as a better and cheaper drug candidate for CMD and also study the signaling pathway which the plant material uses to regulate the metabolic consequences.

Effect of β-Caryophyllene on oxidative stress, glucose metabolism in the skeletal muscle of high fat diet and fructose-induced type-2 diabetic adult male rats

Skeletal muscle is where the majority of insulin-stimulated whole-body glucose elimination takes place under normal circumstances. A significant risk factor for metabolic diseases is high dietary fat consumption, which also increases stored fat mass. Natural solutions with anti-diabetic effectiveness and fewer side effects are becoming more popular as a result of the conventional pharmacological treatments' numerous negative side effects and high rates of secondary failure. Cannabis and a variety of culinary herbs and spices may include the naturally occurring sequiterpene β-caryophyllene. Among other things, it has antioxidant, anti-inflammatory, and anti-lipidemic properties. However, it is not yet known how β-caryophyllene affects the uptake and oxidation of glucose. Determining if β -caryophyllene has anti-diabetic properties in type-2 diabetes brought on by a high-fat diet was the objective of the current investigation. A sufficient dose of β-caryophyllene (200 mg/kg b.w.t., orally for 30 days) was given to type-2 diabetic rats fed a high-fat diet and given fructose as an inducer of diabetes to assess its anti-diabetic activity. The treatment of diabetes-induced rats with β -Caryophyllene restored the altered levels of blood glucose, serum insulin as well as the lipid parameters, oxidative stress markers, antioxidant enzymes. Our findings show that β-caryophyllene improves glycemia control by enhancing glucose absorption and oxidation in the skeletal muscle of type-2 diabetic rats. From the present findings, it is evident that β -caryophyllene can be used as an anti-diabetic drug.

Anti-Glucotoxicity Effect of Phytoconstituents via Inhibiting MGO-AGEs Formation and Breaking MGO-AGEs

The therapeutic benefits of phytochemicals in the treatment of various illnesses and disorders are well documented. They show significant promise for the discovery and creation of novel medications for treating a variety of human diseases. Numerous phytoconstituents have shown antibiotic, antioxidant, and wound-healing effects in the conventional system. Traditional medicines based on alkaloids, phenolics, tannins, saponins, terpenes, steroids, flavonoids, glycosides, and phytosterols have been in use for a long time and are crucial as alternative treatments. These phytochemical elements are crucial for scavenging free radicals, capturing reactive carbonyl species, changing protein glycation sites, inactivating carbohydrate hydrolases, fighting pathological conditions, and accelerating the healing of wounds. In this review, 221 research papers have been reviewed. This research sought to provide an update on the types and methods of formation of methylglyoxal-advanced glycation end products (MGO-AGEs) and molecular pathways induced by AGEs during the progression of the chronic complications of diabetes and associated diseases as well as to discuss the role of phytoconstituents in MGO scavenging and AGEs breaking. The development and commercialization of functional foods using these natural compounds can provide potential health benefits.

Mechanistic Insight of Synthesized 1,4-Dihydropyridines as an Antidiabetic Sword against Reactive Oxygen Species

The pharmacologically privileged DHP derivatives were synthesized using the pragmatic multicomponent Hantzsch synthesis to screen the antidiabetic activity. Initially, the candidates were screened using an in vivo blood glucose test, where compound 8b showed the most prominent antidiabetic effect (% potency = 218%) compared to glimepiride. Then, a propositioned structure-activity relationship study was executed to reveal that longer side chains decreased the DHP's antidiabetic action. Mechanistically, compound 8b diminished ROS in β-cells and muscle cells simultaneously, which was proved by enhanced serum biochemical markers. Also, compound 8b decreased blood glucose by α-glucosidase inhibition (IC₅₀ = 4.48 ± 0.32 μM), compared to acarbose (7.40 ± 0.41 μM), based selectively on the plasma window of 8b. Acarbose demonstrated auspicious inhibitor activity according to the binding affinity (ΔG_binding), which was slightly lower than that of compound 8b (-54.7 and -46.8 kcal/mol, respectively). During the 100 ns molecular dynamics simulations, the structural and energetic assessments exposed the high consistency of compound 8b to bind to the α-glucosidase.

Hypoglycemic Effect of the N-Butanol Fraction of Torreya grandis Leaves on Type 2 Diabetes Mellitus in Rats through the Amelioration of Oxidative Stress and Enhancement of β-Cell Function

Materials and Methods

Sprague-Dawley rats were randomly divided into six groups: control, T2DM, metformin, high-dose BFTL (800 mg/kg), middle-dose BFTL (400 mg/kg), and low-dose BFTL (200 mg/kg). After 4 weeks of BFTL treatment, the correlations of serum indicators with protein expression in tissue were determined, and pathological changes in the liver, kidneys, and pancreas were analyzed.

Results

Compared with the results in the T2DM group, serum fasting blood glucose, triglyceride, total cholesterol, malondialdehyde, alanine aminotransferase, and aspartate aminotransferase levels were significantly decreased (p < 0.05), whereas superoxide dismutase and glutathione peroxidase levels were significantly increased (p < 0.05) in the high-, middle-, and low-dose BFTL groups. The treatment also improved oral glucose tolerance. In addition, the pathological changes of the liver, kidney, and pancreas were improved by BFTL treatment. Cytochrome and caspase-3 expression in pancreatic was significantly decreased (p < 0.05) by BFTL treatment, whereas the Bcl-2/Bax ratio was significantly increased (p < 0.05). Discussion and Conclusion. BFTL exerted significant hypoglycemic effect on T2DM model rats, and its mechanism involved the suppression of blood glucose levels and oxidative stress by improving the metabolism of blood lipids and antioxidant capacity, boosting β-cell function, and inhibiting β-cell apoptosis.

Production of lactones for flavoring and pharmacological purposes from unsaturated lipids: an industrial perspective

The enantiomeric pure and natural (+)-Lactones (C ≤ 14) with aromas obtained from fruits and milk are considered flavoring compounds. The flavoring value is related to the lactones' ring size and chain length, which blend in varying concentrations to produce different stone-fruit flavors. The nature-identical and enantiomeric pure (+)-lactones are only produced through whole-cell biotransformation of yeast. The industrially important γ-decalactone and δ-decalactone are produced by a four-step aerobic-oxidation of ricinoleic acid (RA) following the lactonization mechanism. Recently, metabolic engineering strategies have opened up new possibilities for increasing productivity. Another strategy for increasing yield is to immobilize the RA and remove lactones from the broth regularly. Besides flavor impact, γ-, δ-, ε-, ω-lactones of the carbon chain (C8-C12), the macro-lactones and their derivatives are vital in pharmaceuticals and healthcare. These analogues are isolated from natural sources or commercially produced via biotransformation and chemical synthesis processes for medicinal use or as active pharmaceutical ingredients. The various approaches to biotransformation have been discussed in this review to generate more prospects from a commercial point of view. Finally, this work will be regarded as a magical brick capable of containing both traditional and genetic engineering technology while contributing to a wide range of commercial applications.

Bioactive terpenoids derived from plant endophytic fungi: An updated review (2011-2020)

Plant endophytes have been considered as novel sources of naturally occurring compounds with various biological activities, including cytotoxic, antimicrobial, anti-inflammatory, anticancer, herbicides, antileishmanial and antioxidant. A variety of specialised products, comprising terpenoids, alkaloids, polyketides, phenolic compounds, coumarins, and quinone derivatives have been reported from various strains. An increasing number of products, especially terpenoids, are being isolated from endophytes. Herein, the isolated new terpenoids from plant endophytic fungi, their hosts, as well as biological activities, from January 2011 until the end of 2020 are reviewed. In this period, 516 terpenoids are classified into monoterpenes (5), sesquiterpenes (299), diterpenes (76), sesterterpens (22), meroterpenes (83), triterpenes (29), and other terpenoids (2), were isolated from different plant endophytic fungi species.

Understanding the mechanism underlying the anti-diabetic effect of dietary component: a focus on gut microbiota

Diabetes has become one of the biggest non-communicable diseases and threatens human health worldwide. The management of diabetes is a complex and multifaceted process including drug therapy and lifestyle interventions. Dietary components are essential for both diabetes management and health and survival of trillions of the gut microbiota (GM). Herein, we will discuss the relationship between diets and GM, the mechanism linking diabetes and gut dysbiosis, and the effects of dietary components (nutrients, phytochemicals, probiotics, food additives, etc.) on diabetes from the perspective of modulating GM. The GM of diabetic patients differs from that of health individuals and GM disorder contributes to the onset and maintenance of diabetes. Studies in humans and animal models consolidate that dietary component is a key regulator of diabetes and increasing evidence suggests that the alteration of GM plays a salient role in dietary interventions for diabetes. Given that diabetes is a major public health issue, especially that diabetes is linked with a high risk of mortality from COVID-19, this review provides compelling evidence for that targeting GM by dietary components is a promising strategy, and offers new insights into potential preventive or therapeutic approaches (dietary and pharmacological intervention) for the clinical management of diabetes.

An Overview of Phytotherapy Used in the Management of Type II Diabetes

Diabetes mellitus is related to unconstrained high blood sugar and linked with long-term impairment, dysfunction and failure of several organs. Since 1980, the global frequency of diabetes has almost doubled in the adult population. In very rare cases due to poor prevention and management programs, diabetes causes worsening of health and reduced lifespan of the world population, thus impacting on the world's economy. Supplements, however, help in the improvement of nutritional deficiencies. Phytotherapeutics has the advantage of being economical and easy to access with marginal side effects. So, it is a preferred candidate for the management of diabetes. Currently, a multitude of pharmaceuticals are used which are obtained from natural sources having medicinal properties. The mechanistic approaches are based on the regulation of insulin signaling pathways, translocation of GLUT-4 receptors and/or activation of PPAR γ. These natural compounds include numerous flavonoids which help in preventing glucose absorption by preventing the absorption of α-amylase and α-glucosidase. But to validate the efficacy and safety profile of these compounds, detailed validatory clinical studies are required. This review majorly focuses on the mechanistic approaches of various naturally derived compounds relevant for the condition of Diabetes Mellitus.

Traditional Uses, Phytochemical Constituents and Pharmacological Properties of Averrhoa carambola L.: A Review

Averrhoa carambola L. (star fruit) is an edible fruit that is extensively cultivated in southern China, Southeast Asia, India, and northern South America. It has a sweet and juicy taste and is frequently used in fruit salads and fruit platters, as a garnish in cocktail drinks and beverages, or squeezed into juice and served as a beverage. Traditionally, it has been used for treating diabetes and diabetic nephropathy, arthralgia, vomiting, lithangiuria, coughing, hangovers, and chronic paroxysmal headache for thousands of years. Currently, approximately 132 compounds have been isolated from A. carambola. Among them, flavonoids, benzoquinone, and their glycosides have been considered as biologically active substances, which are responsible for various biological activities. Pharmacological studies have revealed that crude extracts or monomeric compounds from A. carambola exhibit multiple bioactivities, such as anti-oxidant, anti-hyperglycemic, anti-obesity, anti-hyperlipidemic, anti-tumor, anti-inflammatory, hepatoprotective, cardioprotective, anti-hypertensive, neuroprotective, and others. Thus, A. carambola is a valuable treatment in Chinese medicine with therapeutic potential for multiple diseases, especially diabetes and diabetes-related diseases. Even though it is a very promising candidate in the development of functional food and the pharmaceutical industry, reports on its bioactivities have only been conducted in vivo and in vitro and there is a gap in research regarding clinical settings and safety. This review therefore provides a comprehensive and systematic overview of current progress on botany, ethnopharmacology, phytochemistry, pharmacology, and toxicity of A. carambola, providing a valuable reference for further developments and applications of A. carambola in the pharmaceutical industry and functional food.

Enhancement of bioavailability and bioactivity of diet-derived flavonoids by application of nanotechnology: a review

Flavonoids, which are a class of polyphenols widely existing in food and medicine, have enormous pharmacological effects. The functional properties of flavonoids are mainly distributed to their anti-oxidative, anticancer, and anti-inflammatoryeffects, etc. However, flavonoids' low bioavailability limits their clinical application, which is closely related to their intestinal absorption and metabolism. In addition, because of the short residence time of oral bioactive molecules in the stomach, low permeability and low solubility in the gastrointestinal tract, flavonoids are easy to be decomposed by the external environment and gastrointestinal tract after digestion. To tackle these obstacles, technological approaches like microencapsulation have been developed and applied for the formulation of flavonoid-enriched food products. In the light of these scientific advances, the objective of this review is to establish the structural requirements of flavonoids for appreciable anticancer, anti-inflammatory, and antioxidant effects, and elucidate a comprehensive mechanism that can explain their activity. Furthermore, the novelty in application of nanotechnology for the safe delivery of flavonoids in food matrices is discussed. After a literature on the flavonoids and their health attributes, the encapsulation methods and the coating materials are presented.

A Review on Antidiabetic Activity of Centaurea spp.: A New Approach for Developing Herbal Remedies

Objective

Diabetes mellitus (DM) is a long-life metabolic disorder, characterized by high blood glucose levels. The hyperglycemic condition generally leads to irreversible nerve injury and vascular damage. Among different types of diabetes, type 2 is more common and has spread all over the world. Although various therapeutic approaches have been developed to control type 2 DM, regulating blood glucose levels has still remained a controversial challenge for patients. Also, most prescription drugs cause different side effects, such as gastrointestinal disorders. Thus, developing novel and efficient antidiabetic agents possessing fewer adverse effects is in high demand.

Method

The literature was comprehensively surveyed via search engines such as Google Scholar, PubMed, and Scopus using appropriate keywords.

Results

Medicinal plants, both extracts and isolated active components, have played a significant role in controlling the blood glucose levels. Good-to-excellent results documented in the literature have made them a precious origin for developing and designing drugs and supplements against DM. Centaurea spp. have been traditionally used for controlling high blood glucose levels. Also, the antidiabetic properties of different species of Centaurea have been confirmed in recent studies through in vitro assays as well as in vivo experiments.

Conclusion

Potent results encouraged us to review their efficacy to open a new horizon for development of herbal antidiabetic agents.

Bioactive Secondary Metabolites of the Genus Diaporthe and Anamorph Phomopsis from Terrestrial and Marine Habitats and Endophytes: 2010-2019

The genus Diaporthe and its anamorph Phomopsis are distributed worldwide in many ecosystems. They are regarded as potential sources for producing diverse bioactive metabolites. Most species are attributed to plant pathogens, non-pathogenic endophytes, or saprobes in terrestrial host plants. They colonize in the early parasitic tissue of plants, provide a variety of nutrients in the cycle of parasitism and saprophytism, and participate in the basic metabolic process of plants. In the past ten years, many studies have been focused on the discovery of new species and biological secondary metabolites from this genus. In this review, we summarize a total of 335 bioactive secondary metabolites isolated from 26 known species and various unidentified species of Diaporthe and Phomopsis during 2010-2019. Overall, there are 106 bioactive compounds derived from Diaporthe and 246 from Phomopsis, while 17 compounds are found in both of them. They are classified into polyketides, terpenoids, steroids, macrolides, ten-membered lactones, alkaloids, flavonoids, and fatty acids. Polyketides constitute the main chemical population, accounting for 64%. Meanwhile, their bioactivities mainly involve cytotoxic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anti-algae, phytotoxic, and enzyme inhibitory activities. Diaporthe and Phomopsis exhibit their potent talents in the discovery of small molecules for drug candidates.

Three common caffeoylquinic acids as potential hypoglycemic nutraceuticals: Evaluation of α-glucosidase inhibitory activity and glucose consumption in HepG2 cells

The demand for plant-derived antidiabetic nutraceuticals is increasing. In this study, the effects of three common caffeoylquinic acids (CQAs) (chlorogenic acid, isochlorogenic acid A, and cynarin) on α-glucosidase activity and glucose consumption in HepG2 cells were systematically compared. Their α-glucosidase inhibitory activities followed the order of isochlorogenic acid A > chlorogenic acid > cynarin. The fluorescence analysis indicated that they exerted the inhibitory role by forming the complex with α-glucosidase at the molar ratio of 1:1. Isochlorogenic acid A possessed the highest binding capacity, followed by chlorogenic acid and cynarin. The effect of caffeoyl group distribution on the α-glucosidase inhibitory activity was clarified by the molecular docking results. In the HepG2 cells, isochlorogenic acid A also showed the best glucose consumption with negligible cytotoxicity, which might be related to its reactive oxygen species scavenging capacity in cells. Our results confirm its potential application as the antidiabetic nutraceutical. PRACTICAL APPLICATIONS: The hypoglycemic activities of three common CQAs (chlorogenic acid, isochlorogenic acid A, and cynarin) were systemically evaluated in this study. Isochlorogenic acid A exhibited the strongest α-glucosidase inhibitory activity and highest glucose consumption in HepG2 cells with low cytotoxicity. The results suggest that isochlorogenic acid A can be used as the potential hypoglycemic nutraceutical in functional foods.

Anti-Osteoporotic Activity of an Edible Traditional Chinese Medicine Cistanche deserticola on Bone Metabolism of Ovariectomized Rats Through RANKL/RANK/TRAF6-Mediated Signaling Pathways

Given the limitations of existing therapeutic agents for treatment of postmenopausal osteoporosis, there still remains a need for more options with both efficacy and less adverse effects. Cistanche deserticola Y. C. Ma is known as a popular tonic herb traditionally used to treatment deficiency of kidney energy including muscle weakness in minority area of Asian counties. Based on the theory of “kidney dominate bone,” an ovariectomized (OVX) rat model of postmenopausal osteoporosis was used to evaluate the therapeutic effect of C. deserticola extract (CDE) on bone loss. Forty eight female Sprague-Dawley rats, aged about 12 weeks, were randomly assigned into six groups including sham group orally administrated with 0.5% carboxymethyl cellulose sodium (CMC-Na) (sham), positive group treated with 1 mg/kg of estradiol valerate (EV), low, moderate, and high dosage groups orally administrated with 200, 400, and 800 mg/kg/day of CDE, respectively. After 3 months of continuous intervention, CDE exhibited significant anti-osteoporotic activity evidenced by the enhanced total bone mineral density, ameliorated bone microarchitecture; increased alkaline phosphatase activity; decreased deoxypyridinoline, cathepsin K, tartrate-resistant acid phosphatase, and malondialdehyde levels; whereas the body, uterus, and vagina weights in OVX rats were not influenced by CDE intervention. In addition, a seemed contradictory phenomenon on levels of calcium and phosphorus between OVX and sham rats were observed and elucidated. Mechanistically, CDE significantly down-regulated the levels of TRAF6, RANKL, RANK, NF-κB, IKKβ, NFAT2, and up-regulated the phosphatidylinositol 3-kinase (PI3K), AKT, osteoprotegerin, and c-Fos expressions, which implied CDE could suppress RANKL/RANK-induced activation of downstream NF-κB and PI3K/AKT pathways, and ultimately, preventing activity of the key osteoclastogenic proteins NFAT2 and c-Fos. All of the data suggested CDE possessed potential anti-osteoporotic activity and this effect was, at least in part, involved in modulation of RANKL/RANK/TRAF6-mediated NF-κB and PI3K/AKT signaling as well as c-Fos and NFAT2 levels. Therefore, CDE may represent a useful promising remedy candidate for treatment of postmenopausal osteoporosis.

The freeze-dried extracts of Rotheca myricoides (Hochst.) Steane & Mabb possess hypoglycemic, hypolipidemic and hypoinsulinemic on type 2 diabetes rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Rotheca myricoides (Hochst.) Steane & Mabb is a plant species used in traditional medicine for the management of diabetes in the lower eastern part of Kenya (Kitui, Machakos and Makueni Counties, Kenya) that is mainly inhabited by the Kamba community.

AIM

This study investigated the antihyperglycaemic, antidyslipidemic and antihyperinsulinemic activity of the freeze-dried extracts of Rotheca myricoides (Hochst.) Steane & Mabb (RME) in an animal model of type 2 diabetes mellitus.

METHODS

Type 2 diabetes was induced by dietary manipulation for 56 days via (high fat- high fructose diet) and intraperitoneal administration of streptozocin (30 mg/kg). Forty freshly-weaned Sprague Dawley rats were randomly assigned into the negative control (high fat/high fructose diet), low dose test (50mg/kg RME, high dose test (100mg/kg RME and positive control (Pioglitazone, 20mg/kg) groups. Fasting blood glucose and body weight were measured at weekly intervals. Oral glucose tolerance tests were performed on days 28 and 56. Lipid profile, hepatic triglycerides, fasting serum insulin levels and serum uric acid were determined on day 56.

RESULTS

The RME possessed significant antihyperglycemic [FBG: 6.5 ± 0.11 mmol/l (negative control) vs. 4.62 ± 0.13 mmol/l (low dose test) vs. 5.25 ± 0.15 mmol/l in (high dose test) vs. 4.33 ± 0.09 mmol/l (positive control): p < 0.0001] and antihyperinsulinemic effects [1.84 ± 0.19 (negative control) vs. (0.69 ± 0.13 (low dose test) vs. (0.83 ± 0.17 (high dose test) vs. (0.69 ± 0.10 (positive control): F (3, 36) = 0.6421: p < 0.0001. The extracts also possessed significant antidyslipidemic effects [LDL levels: 3.52 ± 0.19 mmol/l (negative control) vs. 0.33 ± 0.14 mmol/l (low dose test) vs. 0.34 ± 0.20 mmol/l (high dose test) vs. 0.33 ± 0.01 mmol/l (positive control): p < 0.0001].RME significantly lowered plasma uric acid levels, as well as hepatic triglycerides and hepatic weights. Network pharmacology analysis indicated that the observed pharmacological effects are mediated via the modulation of Peroxisome proliferator-activated gamma receptor.

CONCLUSIONS

The freeze dried extracts of Rotheca myricoides possessed significant antihyperglycemic and antidyslidemic effects. In addition it lowered serum uric levels, as well as hepatic triglycerides and hepatic weight. These results appear to validate the traditional use of this plant species in the management of diabetes mellitus.

Evaluation of the Anti-Diabetic Activity of Some Common Herbs and Spices: Providing New Insights with Inverse Virtual Screening

Culinary herbs and spices are widely used as a traditional medicine in the treatment of diabetes and its complications, and there are several scientific studies in the literature supporting the use of these medicinal plants. However, there is often a lack of knowledge on the bioactive compounds of these herbs and spices and their mechanisms of action. The aim of this study was to use inverse virtual screening to provide insights into the bioactive compounds of common herbs and spices, and their potential molecular mechanisms of action in the treatment of diabetes. In this study, a library of over 2300 compounds derived from 30 common herbs and spices were screened in silico with the DIA-DB web server against 18 known diabetes drug targets. Over 900 compounds from the herbs and spices library were observed to have potential anti-diabetic activity and liquorice, hops, fennel, rosemary, and fenugreek were observed to be particularly enriched with potential anti-diabetic compounds. A large percentage of the compounds were observed to be potential polypharmacological agents regulating three or more anti-diabetic drug targets and included compounds such as achillin B from yarrow, asparasaponin I from fenugreek, bisdemethoxycurcumin from turmeric, carlinoside from lemongrass, cinnamtannin B1 from cinnamon, crocin from saffron and glabridin from liquorice. The major targets identified for the herbs and spices compounds were dipeptidyl peptidase-4 (DPP4), intestinal maltase-glucoamylase (MGAM), liver receptor homolog-1 (NR5A2), pancreatic alpha-amylase (AM2A), peroxisome proliferator-activated receptor alpha (PPARA), protein tyrosine phosphatase non-receptor type 9 (PTPN9), and retinol binding protein-4 (RBP4) with over 250 compounds observed to be potential inhibitors of these particular protein targets. Only bay leaves, liquorice and thyme were found to contain compounds that could potentially regulate all 18 protein targets followed by black pepper, cumin, dill, hops and marjoram with 17 protein targets. In most cases more than one compound within a given plant could potentially regulate a particular protein target. It was observed that through this multi-compound-multi target regulation of these specific protein targets that the major anti-diabetic effects of reduced hyperglycemia and hyperlipidemia of the herbs and spices could be explained. The results of this study, taken together with the known scientific literature, indicated that the anti-diabetic potential of common culinary herbs and spices was the result of the collective action of more than one bioactive compound regulating and restoring several dysregulated and interconnected diabetic biological processes.

Inhibitory effects of selected antibiotics on the activities of α-amylase and α-glucosidase: In-vitro, in-vivo and theoretical studies

Antibiotics are effective drugs that are used to treat infectious diseases either by killing bacteria or slowing down their growth. The well-adapted structural features of antibiotics for the inhibition/activation of enzymes include several available hydrogen bond (H-bond) acceptors and donors, flexible backbone and hydrophobic nature. The substrates of α-amylase and α-glucosidase, known as key absorbing enzymes, have functional groups (OH groups) rembling antibiotics. Given the possibility of developing in diabetics and the significant association between diabetes and infection, the present study was conducted to investigate the influences of tetracycline (TET), kanamycin (KANA), lincomycin (LIN), erythromycin (ERM) and azithromycin (AZM) on α-glucosidase and α-amylase activities with calculating IC₅₀ and K_i values. Also, the efficacy of antibiotics after oral administration was evaluated by analysis of blood glucose concentrations in rats, as well as a molecular docking analysis was explored. α-glucosidase and α-amylase activities were inhibited in a dose dependent fashion by TET with an IC₅₀ of 38.7 ± 1.4 and 47.8 ± 3.2 μM respectively, by KANA with an IC₅₀ of 46.2 ± 1.6 and 65.1 ± 1.6, by LIN with an IC₅₀ of 59.1 ± 2.1 and 51.3 ± 4.1, by ERM with an IC₅₀ of 94.9 ± 4.7 and 65.7 ± 3.8 and by AZM with an IC₅₀ of 69.4 ± 4.4 and 103.6 ± 6.2. Moreover, the K_i values of TET were calculated as 4.4 ± 0.6 and 8.4 ± 0.8 μM for α-glucosidase and α-amylase in a competitive-mode and mixed-mode inhibition. In addition, to communicate with the active site of α-glucosidase and α-amylase respectively, TET presented a binding energy of -9.8 and -8.8 kcal/mol, KANA -7.9 and -7.1, LIN -7.8 and -6.7, ERM -6.8 and -6.4, and AZM -6.4 and -7.5 kcal/mol. In-vivo studies also suggested a decrease in the blood glucose concentration after administering TET compared to the positive controls (P < 0.01). The results obtained from the present research can therefore help the scientific community explore the possible interconnection between the clinical side-effects of antibiotics and their α-glucosidase and α-amylase inhibitory properties, as the target enzymes in hypoglycemia conditions.