Enzymes inhibitors from natural sources with antidiabetic activity: A review

Different extraction methods shape the phenolic signature and biological activity of Morinda lucida extracts: A novel source of bioactive compounds preparing functional applications

The extraction of bioactive compounds is based on the application of various extraction techniques. Therefore, the stem and root bark of the plant species Morinda lucida L. were used in this research, while the extraction procedure was performed using three extraction techniques: HAE (homogenizer extraction), UAE (ultrasound extraction) as modern, and MAC (maceration) as conventional extraction technique. The presence of different classes of secondary metabolites was determined using the UHPLC method, while the content of total phenols and flavonoids was determined spectrophotometrically. The biological potential was investigated by in vitro antioxidant and enzyme assays. Different extraction technologies showed significant differences in only two classes of phenols, namely lignans and phenolic acids, which were significantly higher in HAE than in UAE and MAC. These findings highlight the significant effect of stem and bark extracts of M. lucida, opening the way for innovative industrial exploitation of these matrices.

Use of Guazuma ulmifolia Lam. Stem Bark Extracts to Prevent High-Fat Diet Induced Metabolic Disorders in Mice

This study aimed to evaluate the effects of supplementation with ethanolic and aqueous extracts from the bark of the stem of Guazuma ulmifolia in mice submitted to a high-fat diet as well as to evaluate the chemical composition of these extracts. The chemical composition and antioxidant potential was evaluated in aqueous and ethanolic extracts of the stem bark. The in vivo test consisted of evaluating the effects of the aqueous and ethanolic extracts of the stem bark on C57BL/6 mice receiving a high-fat diet. The animals were evaluated for weight gain, feed consumption, visceral adiposity, serum, and inflammatory and hormonal parameters. The results of the chemical analyses corroborate those obtained by the literature, which reported gallocatechin, epigallocatechin and epigallocatechin gallate. Compared with the ethanolic extract, the aqueous extract showed greater antioxidant capacity. Both extracts resulted in lower feed consumption in the animals, but they did not influence weight gain or visceral adiposity and resulted in varied changes in the lipid profile. In addition, they did not influence glucose tolerance, insulin sensitivity, or fasting blood glucose. Furthermore, the leptin levels increased, which may have contributed to satiety, but this was shown to have a negative impact on other inflammatory and hormonal parameters. Therefore, under the conditions of this study, the biologically active compounds present in the plant species Guazuma ulmifolia were not able to contribute to the treatment of metabolic changes related to the consumption of a high-fat diet.

Antioxidant, Anti-Inflammatory, Anti-Diabetic, and Pro-Osteogenic Activities of Polyphenols for the Treatment of Two Different Chronic Diseases: Type 2 Diabetes Mellitus and Osteoporosis

Polyphenols are natural bioactives occurring in medicinal and aromatic plants and food and beverages of plant origin. Compared with conventional therapies, plant-derived phytochemicals are more affordable and accessible and have no toxic side effects. Thus, pharmaceutical research is increasingly inclined to discover and study new and innovative natural molecules for the treatment of several chronic human diseases, like type 2 diabetes mellitus (T2DM) and osteoporosis. These pathological conditions are characterized by a chronic inflammatory state and persistent oxidative stress, which are interconnected and lead to the development and worsening of these two health disorders. Oral nano delivery strategies have been used to improve the bioavailability of polyphenols and to allow these natural molecules to exert their antioxidant, anti-inflammatory, anti-diabetic, and pro-osteogenic biological activities in in vivo experimental models and in patients. Polyphenols are commonly used in the formulations of nutraceuticals, which can counteract the detrimental effects of T2DM and osteoporosis pathologies. This review describes the polyphenols that can exert protective effects against T2DM and osteoporosis through the modulation of specific molecular markers and pathways. These bioactives could be used as adjuvants, in combination with synthetic drugs, in the future to develop innovative therapeutic strategies for the treatment of T2DM and osteoporosis.

Inhibitory effects of methanolic extracts from the stem barks of ten Mexican Bursera Jacq. ex L. species on the activity of α-amylase and acetylcholinesterase from Tenebrio molitor

Methanolic stem bark extracts from ten Mexican Bursera Jacq. ex L. species were evaluated in vitro with regard to their inhibitory activity against two Tenebrio molitor-derived enzymes. Seven extracts (B. bicolor, B. copallifera, B. fagaroides, B. grandifolia, B. lancifolia, B. linanoe, and B. longipes) reduced α-amylase activity by 55.37% to 96.25%, with three samples proving to be particularly potent α-amylase inhibitors (B. grandifolia, B. lancifolia, and B. linanoe; IC50 = 162, 132, and 186 µg/mL, respectively). In contrast, no extract inhibited acetylcholinesterase activity by more than 39.94%. Quantitative HPLC analysis did not reveal any clear correlation between the species-specific flavonoid or phenolic acid profiles and the respective extracts' enzyme inhibitory activity. The findings reported herein do not only contribute to improving the current state of knowledge regarding the enzyme inhibitory potential of the Bursera genus, but could also lead to the development of new sustainable bioinsecticides.

Pectin as a biofunctional food: comprehensive overview of its therapeutic effects and antidiabetic-associated mechanisms

Pectin is a complex polysaccharide found in a variety of fruits and vegetables. It has been shown to have potential antidiabetic activity along with other biological activities, including cholesterol-lowering properties, antioxidant activity, anti-inflammatory and immune-modulatory effects, augmented healing of diabetic foot ulcers and other health benefits. There are several pectin-associated antidiabetic mechanisms, such as the regulation of glucose metabolism, reduction of oxidative stress, increased insulin sensitivity, appetite suppression and modulation of the gut microbiome. Studies have shown that pectin supplementation has antidiabetic effects in different animal models and in vitro. In human studies, pectin has been found to have a positive effect on blood glucose control, particularly in individuals with type 2 diabetes. Pectin also shows synergistic effects by enhancing the potency and efficacy of antidiabetic drugs when taken together. In conclusion, pectin has the potential to be an effective antidiabetic agent. However, further research is needed to fully understand its detailed molecular mechanisms in various animal models, functional food formulations and safety profiles for the treatment and management of diabetes and associated complications in humans. The current study was carried out to provide the critical approach towards therapeutical potential, anti-diabetic potential and underlying molecular mechanisms on the basis of existing knowledge.

Anti-diabetic, anti-pancreatic lipase, and anti-protein glycation potential of Irvingia gabonensis stem bark extracts: in vitro and in silico studies

Diabetes mellitus is a chronic metabolic disorder that affects glucose, lipid, and protein metabolism. Targeting these metabolic derangements can optimize the therapeutic strategies for this disease. Utilizing in vitro and in silico models, this study investigated the ability of aqueous and ethanol extracts of Irvingia gabonensis to inhibit α-amylase, α-glucosidase, pancreatic lipase, and protein glycation. High-performance liquid chromatography (HPLC) was used to identify the compounds found in the stem bark of I. gabonensis. In silico analysis determined the binding mode and mechanism of interactions between the enzymes and phytochemicals. With an IC50 value of 11.47 µg/ml, the aqueous extract demonstrated higher inhibitory efficacy against α-amylase compared to the ethanol extract (IC50 19.88 µg/ml). However, the ethanol extract had stronger inhibitory activities against α-glucosidase, pancreatic lipase, and protein glycation compared to the aqueous extract (IC50 values of 3.05, 32.85, 0.0014 versus 25.72, 332.42, 0.018 µg/ml respectively). Quercetin ranked highest in binding energy with α-amylase (-6.6 kcal/mol), α-glucosidase (-6.6 kcal/mol), and pancreatic lipase (-5.6 kcal/mol). This was followed by rhamnetin (6.5, 6.5, and 6.1 kcal/mol respectively). Hydrogen bonding, hydrophobic interactions, and pi-pi stacking are forces responsible for the binding of quercetin and rhamnetin to these enzymes. Molecular dynamics simulation showed that the lead phytochemicals formed stable and energetically stabilized complexes with the target proteins. This study showed that the extracts of I. gabonensis stem bark had significant in vitro anti-diabetic, anti-pancreatic lipase, and anti-protein glycation activities. The strong binding affinities of some of the identified compounds could be responsible for the inhibitory potential of the extracts. I. gabonensis stem bark could be further explored as a natural remedy for the treatment of diabetes mellitus and its complications.

The Potential of Crude and Partially Purified Black Rice Bran Extracts Obtained by Ultrasound-Assisted Extraction: Anti-Glycemic, Cytotoxicity, Cytoprotective, and Antitumoral Effects

Recovering anthocyanins from black rice bran is a way of valuing this byproduct, by obtaining an extract with biological potential. The objective of this study was to recover anthocyanins using ultrasound-assisted extraction. Some of the extract was partially purified, and both (crude and partially purified) extracts were evaluated for their anthocyanin content, antioxidant activity, antidiabetic and antitumoral activities, cytotoxicity, and oxidative stress. An increase in the laboratory scale was also achieved, making possible to increase the extraction volume up to 20 times without significantly changing the content of anthocyanins (1.85 mg C3G/g DW). It was found that the purified sample presented a 4.2 times higher value of total anthocyanins compared to the crude sample. The best IC50 values for the purified sample were verified by DPPH and ABTS (0.76 and 0.33 mg/mL). The best results for antidiabetic activity were obtained for the partially purified sample: 0.82 µM C3G for α-glucosidase and 12.5 µM C3G for α-amylase. The extracts demonstrated protection (~70%) when subjected to the oxidative stress of L929 cells. An antitumoral effect of 25-30% for both extracts was found in A459 cells. The crude and partially purified extracts of black rice have antidiabetic and anticancer effects and more studies are needed to explore their potential.

Elucidating the chemical profile and biological studies of Verbascum diversifolium Hochst. extracts

The present study was designed to evaluate the chemical composition, antioxidant, enzyme inhibition and cytotoxic properties of different extracts from aerial parts of V. diversifolium (family Scrophulariaceae), a plant that is native to Lebanon, Syria and Turkey. Six extracts, namely, hexane, dichloromethane (DCM), ethyl acetate (EtOAc), ethanol (EtOH), 70% EtOH, and water (aqueous) were prepared by maceration. The EtOH extract was predominated by the presence of rutin (4280.20 μg g-1) and p-coumaric acid (3044.01 μg g-1) while the highest accumulation of kaempferol-3-glucoside (1537.38 μg g-1), caffeic acid (130.13 μg g-1) and 4-hydroxy benzoic acid (465.93 μg g-1) was recorded in the 70% EtOH, aqueous, and EtOAc extracts, respectively. The EtOH (46.86 mg TE/g) and 70% EtOH (46.33 mg TE/g) extracts displayed the highest DPPH radical scavenging result. Both these extracts, along with the aqueous one, exerted the highest ABTS radical scavenging result (73.03-73.56 mg TE/g). The EtOH and 70% EtOH extracts revealed the most potent anti-AChE (2.66 and 2.64 mg GALAE/g) and anti-glucosidase (1.07 and 1.09 mmol ACAE/g) activities. The aqueous extract was the most efficacious in inhibiting the proliferation of prostate cancer (DU-145) cells with an IC50 of 8.71 μg/mL and a Selectivity Index of 3.7. In conclusion, this study appraised the use of V. diversifolium aerial parts as a potential therapeutic source for future development of phytopharmaceuticals that target specific oxidative stress-linked diseases including diabetes, cancer, cardiovascular disease, and Alzheimer's disease among others.

α-Pinene, a Main Component of Pinus Essential Oils, Enhances the Expression of Insulin-Sensitive Glucose Transporter Type 4 in Murine Skeletal Muscle Cells

Glucose transporter-4 (GLUT4) represents the major glucose transporter isoform responsible for glucose uptake into insulin-sensitive cells, primarily in skeletal muscle and adipose tissues. In insulin-resistant conditions, such as type 2 diabetes mellitus, GLUT4 expression and/or translocation to the cell plasma membrane is reduced, compromising cell energy metabolism. Therefore, the use of synthetic or naturally occurring molecules able to stimulate GLUT4 expression represents a good tool for alternative treatments of insulin resistance. The present study aimed to investigate the effects of essential oils (EOs) derived from Pinus spp. (P. nigra and P. radiata) and of their main terpenoid constituents (α- and β-pinene) on the expression/translocation of GLUT4 in myoblast C2C12 murine cells. For this purpose, the chemical profiles of the EOs were first analyzed through gas chromatography-mass spectrometry (GC-MS). Cell viability was assessed by MTT assay, and GLUT4 expression/translocation was evaluated through RT-qPCR and flow cytometry analyses. The results showed that only the P. nigra essential oil (PnEO) and α-pinene can increase the transcription of the Glut4/Scl2a4 gene, resulting in a subsequent increase in the amount of GLUT4 produced and its plasma membrane localization. Moreover, the PnEO or α-pinene can induce Glut4 expression both during myogenesis and in myotubes. In summary, the PnEO and α-pinene emulate insulin's effect on the GLUT4 transporter expression and its translocation to the muscle cell surface.

Triazolopyrimidine Derivatives: An Updated Review on Recent Advances in Synthesis, Biological Activities and Drug Delivery Aspects

Molecules containing triazolopyrimidine core showed diverse biological activities, including anti-Alzheimer's, anti-diabetes, anti-cancer, anti-microbial, anti-tuberculosis, anti-viral, anti-malarial, anti-inflammatory, anti-parkinsonism, and anti-glaucoma activities. Triazolopyrimidines have 8 isomeric structures, including the most stable 1,2,4-triazolo[1,5- a] pyrimidine ones. Triazolopyrimidines were obtained by using various chemical reactions, including a) 1,2,4-triazole nucleus annulation to pyrimidine, b) pyrimidines annulation to 1,2,4-triazole structure, c) 1,2,4-triazolo[l,5-a] pyrimidines rearrangement, and d) pyrimidotetrazine rearrangement. This review discusses synthetic methods, recent pharmacological actions and drug delivery perspectives of triazolopyrimidines.

Protective effects and mechanisms of Momordica charantia polysaccharide on early-stage diabetic retinopathy in type 1 diabetes

Momordica charantia polysaccharide (MCP) is a potential drug for the prevention and alleviation of diabetes mellitus (DM) and diabetic retinopathy (DR). This study aimed to investigate the potential protective effects of MCP on early-stage DR and explore the underlying mechanisms. The model group (DM group) and treatment group (D+H group) were established by inducing type 1 DM using a single dose of streptozotocin (STZ) at 60 mg/kg. After modeling, the D+H group was orally administered a 500 mg/kg dose of MCP solution once daily for 12 weeks. Monitoring of systemic indicators (FBG, body weight, general condition) and retinal tissue inflammation and apoptosis (HE staining, IL-6, MCP-1, TNF-α, VEGF, NF-κB, Caspase-3) in this study demonstrated that MCP intervention alleviated both DM and DR. MCP improved the body weight and general condition of DM rats by reducing FBG levels. It also enhanced the anti-inflammatory and anti-apoptotic capabilities of retinal neurons and microvessels by modulating the actions of cytokines, thereby further regulating the inflammation and apoptosis of retinal neurons and microvessels. The underlying mechanisms may be associated with the downregulation of NF-κB and Caspase-3 pathway protein expression, as well as the downregulation of mRNA expression of NF-κB and Caspase-3 pathway genes. Further research is needed to elucidate the potential mechanisms underlying the protective effects of MCP on DR. MCP may emerge as a selective medication for the prevention and alleviation of DM and a novel natural medicine for the prevention and alleviation of DR.

Comparison of inhibitory activities of 50 Salvia species against α-Glucosidase

Objectives

Type 2 diabetes is a common metabolic disease affecting millions of people worldwide. α-Glucosidase inhibitors can be used as one of the therapeutic approaches to decrease the postprandial glucose levels through the inhibition of carbohydrate hydrolysis. Medicinal plants are one of the main sources of α-glucosidase's natural inhibitors. In this study, we report the inhibitory effects of 50 different accessions of 32 Salvia species against α-glucosidase.

Methods

To estimate the relative potency of the crude extracts, the inhibitory activities of the 80% methanol of the plants extracts were determined in three different concentrations (1000, 500 and 250 µg/ml) and compared to that of acarbose as the positive control.

Results

S. multicaulis, S. santolinifolia, S. dracocephaloides, and S. eremophila were stronger inhibitors than acarbose (p < 0.05) with IC50 values in the range of 26.23- 92.35 µg/mL. According to the LC-PDA-ESIMS and NMR analysis of crude extracts of the studied Salvia species, 8 phytochemicals including luteolin-7-O-glucoside (1) luteolin-7-O-glucuronide (2), apigenin-7-O-glucoside (3), apigenin-7-O-glucuronide (4), Hispidulin-7-O-glucuronide (5), hispidulin-7-O-glucoside (6), rosmarinic acid (7), carnosol (8) and carnosic acid (9) were identified as the most common α-glucosidase inhibitors. The above compounds constituted the major compounds in the active Salvia species in the range of 1.5-95.0%. Among them rosmarinic acid (39-95%) was detected in almost all potent α -glucosidase inhibitor species. Therefore, it can be considered as a biochemical marker in the antidiabetic Salvia species in addition to the other minor compounds.

Conclusions

Considering the high α-glucosidase inhibitory potential of the four- out of fifty Salvia species, they are suggested for further in vivo antidiabetic tests as potential medicinal plants.

A descriptive survey study in endocrinology clinic: evaluation of the use of natural products

OBJECTIVE

The use of herbal products/dietary supplements (HP/DS) in endocrinal chronic diseases is growing. However, no studies have evaluated their use in patients who present to endocrinology and metabolic diseases clinics. This descriptive study aims to investigate the rate of HP/DS use and the factors affecting this in patients who presented to Karadeniz Technical University (KTU) Farabi Hospital Endocrinology and Metabolic Diseases Clinic, Türkiye between 01.11.2021 and 01.05.2022.

METHODS

Five hundred six questionnaires with acceptable data quality were included this investigation. The data were analyzed on SPSS version 23.0 software. The factors with the greatest effect on the use of HP/DS were determined using binary logistic regression analysis.

RESULTS

Analysis showed that 49.4% of the participants used HP/DS. The main factors affecting the use of herbal products were age, diagnosis of the disease, and treatment compliance problems. The most frequently used products were lemon, cinnamon, black cumin, ginger, turmeric, and dill. The participants main sources of information about HP/DS were friends/relatives, the internet/social media, and television, respectively. 74.8% of the participants using HP/DS did not inform their physcisian/pharmacist about such use, although 81.8% of these nevertheless wished to receive information from these occupational groups.

CONCLUSION

Herbal product monitoring in patients should be performed in collaboration with pharmacists, herbal product use should be investigated, and counseling services should be made available in order to maintain and promote public health.

Chemical Diversity and Medicinal Potential of Vitex negundo L.: From Traditional Knowledge to Modern Clinical Trials

BACKGROUND

In Vedic context, Nirgundi (V. negundo) has been utilized for its anti-inflammatory, analgesic, and wound-healing properties. It has been employed to alleviate pain, treat skin conditions, and address various ailments. The plant's leaves, roots, and seeds have all found applications in traditional remedies. The knowledge of Nirgundi's medicinal benefits has been passed down through generations, and it continues to be a part of Ayurvedic and traditional medicine practices in India.

Phytochemical Content and Antidiabetic Properties of Most Commonly Used Antidiabetic Medicinal Plants of Kenya

Traditional medicinal plants have been used for decades in folk medicines in the treatment and management of several ailments and diseases including diabetes, pain, ulcers, cancers, and wounds, among others. This study focused on the phytochemical and antidiabetic activity of the commonly used antidiabetic medicinal species in Kenya. Phytochemical profiling of these species revealed flavonoids and terpenoids as the major chemical classes reported which have been linked with strong biological activities against the aforementioned diseases, among others. However, out of the selected twenty-two species, many of the natural product isolation studies have focused on only a few species, as highlighted in the study. All of the examined crude extracts from thirteen antidiabetic species demonstrated strong antidiabetic activities by inhibiting α-glucosidase and α-amylase among other mechanisms, while nine are yet to be evaluated for their antidiabetic activities. Isolated compounds S-Methylcysteine sulfoxide, quercetin, alliuocide G, 2-(3,4-Dihydroxybenzoyl)-2,4,6-trihydroxy-3 (2H)-benzofuranone, Luteolin-7-O-D-glucopyranoside, quercetin, 1,3,11α-Trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-7-on-2-yl)-5α-(3,4-dihydroxy-phenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one and [1,3,11α-Trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-7-on-2-yl)-5α-(3,4-dihydroxy-phenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one]-4'-O-D-gluco-pyranoside from Allium cepa have been found to exhibit significant antidiabetic activities. With the huge number of adults living with diabetes in Kenya and the available treatment methods being expensive yet not so effective, this study highlights alternative remedies by documenting the commonly used antidiabetic medicinal plants. Further, the study supports the antidiabetic use of these plants with the existing pharmacological profiles and highlights research study gaps. Therefore, it is urgent to conduct natural products isolation work on the selected antidiabetic species commonly used in Kenya and evaluate their antidiabetic activities, both in vitro and in vivo, to validate their antidiabetic use and come up with new antidiabetic drugs.

Tracing the volatilomic fingerprint of grape pomace as a powerful approach for its valorization

The huge amount of grape pomace (GP) generated every year worldwide, particularly in Europe, creates negative impacts at the economic and environmental levels. As far as we know, scarce research has been done on the volatilomic fingerprint of GP. To meet consumer demand for healthy foods, there is a growing interest in the characterization of particular volatile organic metabolites (VOMS) in GP that can be used for industrial applications, including the food industry. In this study, the volatilomic fingerprint of GP obtained from different Vitis vinifera L. grapes was established by solid phase microextraction (HS-SPME) combined to gas chromatography-mass spectrometry (GC-MS), to explore the properties of most dominant VOMs in a context of its application on marketable products. A total of 52 VOMs belonging to different chemical families were identified. Alcohols, carbonyl compounds, and esters, are the most dominant, representing 38.8, 29.3, and 24.2% of the total volatile profile of the investigated GP, respectively. Esters (e.g., isoamyl acetate, hexyl acetate, ethyl hexanoate) and alcohols (e.g., 3-methyl butan-2-ol, hexan-1-ol) can be used as flavoring agents with potential use in the food industry, and in the cosmetic industry, for fragrances production. In addition, the identified terpenoids (e.g., menthol, ylangene, limonene) exhibit antioxidant, antimicrobial, and anticancer, biological properties, among others, boosting their potential application in the pharmaceutical industry. The obtained results revealed the potential of some VOMs from GP to replace synthetic antioxidants, colorants, and antimicrobials used in the food industry, and in the cosmetic and pharmaceutical industry, meeting the increasing consumer demand for natural alternative compounds.

Isolation of phenolic compound from Lawsonia inermis and its prediction as anti-diabetic agent using molecular docking and molecular dynamic simulation

High blood sugar is a defining feature of chronic disease, diabetes mellitus (DM). There are numerous commercially available medications for the treatment of DM. However, managing the patient's glucose levels remain a challenge because of the gradual reduction in beta-cell function and some side effects from the long-term use of various medications. Previous research has shown that the phenolic compound of henna plant (Lawsonia inermis L.) has the potential as anti-diabetic agent since it is able to suppress the digesting of α-amylase enzyme. In these studies, the plant' phenolic compounds have been isolated and characterized using UV, IR, NMR and LC-MS methods. Furthermore, the compound interaction into the active site of the α-amylase enzyme has been analyzed using molecular docking and molecular dynamics, as well as into α-glucosidase enzyme for predicting of the affinities. The results showed that isolated compound has the molecular formula of C15H10O6 with eleven degrees of unsaturation (DBE; double bond equivalence). The DBE value corresponds to the structure of the luteolin compound having an aromatic ring (8), a carbonyl group on the side chain (1) and a ketone ring with (2). The interaction study of the isolated compound with α-amylase and α-glucosidase enzyme using molecular docking compared to the positive control (acarbose) gave binding energy of -8.03 and -8.95 kcal/mol, respectively. The molecular dynamics simulation using the MM-PBSA method, complex stability based on solvent accessible surface area (SASA), root mean square deviation (RMSD), and root mean square fluctuation (RMSF) revealed that the compound has a high affinity for receptors. The characteristics of skin permeability, absorption, and distribution using ADME-Tox model were also well predicted. The results indicate that the phenolic compound isolated from L. inermis leaf was luteolin and it has the potential as an anti-diabetic agent.Communicated by Ramaswamy H. Sarma.

Exploring plant-based alpha-glucosidase inhibitors: promising contenders for combatting type-2 diabetes

Objective: This systematic review aimed to provide comprehensive details on the α-G inhibitory potential of various bioactive compounds derived from natural sources.Methods: A comprehensive literature search was conducted using various databases and search engines, including Science Direct, Google Scholar, SciFinder, Web of Science, and PubMed until May, 2023.Results and conclusions: The enzyme alpha-glucosidase (α-G) is found in the brush border epithelium of the small intestine and consists of duplicated glycoside hydrolase (GH31) domain. It involves the conversion of disaccharides and oligosaccharides into monosaccharides by acting on alpha (1 → 4) and (1 → 6) linked glucose residue. Once absorbed, glucose enters the bloodstream and elevates postprandial glucose, which is associated with the development of type 2 Diabetes (T2D). Epidemic obesity, cardiovascular disease, and nephropathy are linked to T2D. Traditional medicinal plants with α-G inhibitory potential are commonly used to treat T2D due to the adverse effects of currently used α-G inhibitors miglitol, acarbose, and voglibose. Various bioactive compounds derived from natural sources, including lupenone, Wilforlide A, Baicalein, Betulinic acid, Ursolic acid, Oleanolic acid, Katononic acid, Carnosol, Hypericin, Astilbin, lupeol, betulonic acid, Fagomine, Lactucaxanthin, Erythritol, GP90-1B, Procyanidins, Galangin, and vomifoliol retain α-G inhibitory potential for regulating hyperglycaemia.

Protective effects and mechanisms of opuntia polysaccharide in animal models of diabetes mellitus: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Opuntia speciesis used in traditional medicine to treat diabetes mellitus (DM). Polysaccharide is one of the main components of Opuntia. Opuntia polysaccharide (OPS) is a kind of natural active macromolecular substance, numerous animal experiments have been conducted to treat DM, however, its protective effect and mechanism in animal models of DM has not been clarified.

AIM OF THE STUDY

The aim of this study is to evaluate the efficacy of OPS on DM through a stematic review and meta-analysis of animal models, and whether its improves blood glucose (BG) levels, body weight (BW), food intake, water intake, and lipid levels, and to summarize the potential mechanism of OPS in the treatment of DM.

MATERIALS AND METHODS

We searched relevant Chinese and English databases from the date of construction to March 2022, including PubMed (MEDLINE), Embase, Cochrane Library, Scopus and Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedicine Literature Database (CBM), Chinese Science and Technology Periodicals Database (VIP), Wanfang Database. 16 studies were included for meta-analysis.

RESULTS

The results showed that compared with the model group, the OPS significantly improved BG, BW, food intake, water intake, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Meta-regression and subgroup analysis showed that intervention dose, animal species, duration and modeling method may be the source of the heterogeneity. There was no statistical difference between the positive control group and the OPS treatment group in improving BW, food intake, water intake, TC, TG, HDL-C, and LDL-C.

CONCLUSIONS

OPS can effectively improve the symptoms of hyperglycemia, polydipsia, polyphagia, low body weight, and dyslipidemia in DM animals. The possible protective mechanisms of OPS on DM animals are immune regulation, repair of damaged pancreatic β cells, and inhibition of oxidative stress and cell apoptosis.

Identification and Isolation of α-Glucosidase Inhibitors from Siraitia grosvenorii Roots Using Bio-Affinity Ultrafiltration and Comprehensive Chromatography

The discovery of bioactive compounds from medicinal plants has played a crucial role in drug discovery. In this study, a simple and efficient method utilizing affinity-based ultrafiltration (UF) coupled with high-performance liquid chromatography (HPLC) was developed for the rapid screening and targeted separation of α-glucosidase inhibitors from Siraitia grosvenorii roots. First, an active fraction of S. grosvenorii roots (SGR2) was prepared, and 17 potential α-glucosidase inhibitors were identified based on UF-HPLC analysis. Second, guided by UF-HPLC, a combination of MCI gel CHP-20P column chromatography, high-speed counter-current countercurrent chromatography, and preparative HPLC were conducted to isolate the compounds producing active peaks. Sixteen compounds were successfully isolated from SGR2, including two lignans and fourteen cucurbitane-type triterpenoids. The structures of the novel compounds (4, 6, 7, 8, 9, and 11) were elucidated using spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. Finally, the α-glucosidase inhibitory activities of the isolated compounds were verified via enzyme inhibition assays and molecular docking analysis, all of which were found to exhibit certain inhibitory activity. Compound 14 exhibited the strongest inhibitory activity, with an IC₅₀ value of 430.13 ± 13.33 μM, which was superior to that of acarbose (1332.50 ± 58.53 μM). The relationships between the structures of the compounds and their inhibitory activities were also investigated. Molecular docking showed that the highly active inhibitors interacted with α-glucosidase through hydrogen bonds and hydrophobic interactions. Our results demonstrate the beneficial effects of S. grosvenorii roots and their constituents on α-glucosidase inhibition.

Potential use of bio functionalized nanoparticles to attenuate triple negative breast cancer (MDA-MB-231 cells)

This study showed that bio-functional silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) were synthesized in aqueous extracts of Gymnema sylvestre leaves and tested for toxicity assessment against triple-negative breast cancer cells (TNBC). Biofunctional nanoparticle (NPs) samples were characterized using UV-Vis spectroscopy, FT-IR, XRD, SEM, and TEM. The results showed that the phytofabrication of AgNPs resulted in a dark brown, UV-vis maximum absorbance peak at 413 nm. The AgNPs were crystalline and spherical, with sizes ranging from 20 to 60 nm, as confirmed by the XRD pattern and TEM images. Another phytofabrication of ZnONPs exhibited a white precipitate corresponding to a UV-Vis maximum absorption peak at 377 nm and a fine micro flower morphology with a particle-sized tribution between 100 and 200 nm. In addition, FT-IR spectra showed that bioorganic compounds are associated with NPs that respond to reduced Ag⁺ ions and AgNPs tabilizers. Invitro cytotoxicity studies revealed the potent anti-cancer effects of phytofabricated AgNPs and ZnONPs on TNBC cells. Furthermore, the AO/EB double staining assay results proved that apoptotic cells are distinguished by greenish-yellow fluorescence of the cell nuclei with IC₅₀ concentrations of 44 ± 0.8 µg/mL for AgNPs and 26.2 ± 0.5 µg/mL for ZnONPs, respectively. Based on our results, we expect that the anticancer function of the biofunctional NPs is due to the apoptotic activation of TNBC cells by increased ROS. Therefore, the presented study demonstrated that biofunctional AgNPs and ZnONPs have excellent prospects for the anti-cancer activity that can be used in pharmaceutical and medical fields.

Rhanteriol, a New Rhanterium suaveolens Desf. Lignan with Pharmacological Potential as an Inhibitor of Enzymes Involved in Neurodegeneration and Type 2 Diabetes

Several specialized plant metabolites are reported to be enzyme inhibitors. In this investigation, the phytochemical composition and the biological activity of Rhanterium suaveolens Desf. were studied. One new lignan (rhanteriol 1) and seven known secondary metabolites were isolated from the aerial parts of R. suaveolens by using different chromatographic procedures. The biological properties of the R. suaveolens extracts and the new compound were evaluated by measuring their ability to inhibit the cholinesterase and carbohydrate-hydrolyzing enzymes, using cell-free in vitro methods. The new lignan, rhanteriol, was shown to inhibit α-amylase and α-glucosidase (IC₅₀ = 46.42 ± 3.25 μM and 26.76 ± 3.29 μM, respectively), as well as butyrylcholinesterase (IC₅₀ = 10.41 ± 0.03 μM), with an effect comparable to that of the respective standards, acarbose and galantamine. Furthermore, docking studies were performed suggesting the interaction mode of rhanteriol with the active sites of the investigated enzymes. The obtained data demonstrated that the aerial part of R. suaveolens could represent a source of active molecules, such as rhanteriol, usable in the development of treatments for preventing or treating type 2 diabetes mellitus and neurodegeneration.

Unveiling the Antioxidant, Clinical Enzyme Inhibitory Properties and Cytotoxic Potential of Tambourissa peltata Baker-An Understudied Endemic Plant

This study documents for the first time the phytochemical composition and biological activities of Tambourissa peltata Baker, an endemic plant from Mauritius. Phytochemical extraction was performed using ethyl acetate, methanol and distilled water as solvents. The phytochemical composition was determined through HPLC-MS and other standard assays. The DPPH, ABTS, FRAP, CUPRAC and phosphomolybdenum assays were employed for the determination of the antioxidant potential, whereas cell viability assays were used to determine the cytotoxicity. The highest phenolic and phenolic acid contents were obtained in the aqueous extract (179.91 ± 0.67 gallic acid equivalents/g and 55.74 ± 1.43 caffeic acid equivalents/g). The highest quantity of flavonoids was obtained in the ethyl acetate extract (28.97 ± 0.46 rutin equivalents/g). The methanolic extract was the highest source of flavonols (33.71 ± 0.13 mg catechin equivalents/g). A total of 34 phytochemicals were identified, mainly proanthocyanidins and flavonoid glycosides. The highest antioxidant activity in DPPH (973.40 ± 5.65 mg TE (Trolox equivalents)/g), ABTS (2030.37 ± 40.83 mg TE/g), FRAP (1461.39 ± 5.95 mg TE/g), CUPRAC (1940.99 ± 20.95 mg TE/g) and phosphomolybdenum (8.37 ± 0.23 mmol TE/g) assays was recorded for the aqueous extract. The ethyl acetate extract was the most active metal chelator. The highest acetylcholinesterase inhibitor was the methanolic extract, whereas the ethyl acetate extract was the most active against BChE. The tyrosinase enzyme was most inhibited by the methanolic extract. Alpha-amylase and glucosidase were most inhibited by the aqueous extract. The methanolic extract was capable of inducing cell cytotoxicity to the human colorectal carcinoma without damaging normal cells. T. peltata warrants further attention from the scientific community given its multifaceted biological properties.

Integrated metabolite analysis and health-relevant in vitro functionality of white, red, and orange maize (Zea mays L.) from the Peruvian Andean race Cabanita at different maturity stages

The high maize (Zea mays L.) diversity in Peru has been recognized worldwide, but the investigation focused on its integral health-relevant and bioactive characterization is limited. Therefore, this research aimed at studying the variability of the primary and the secondary (free and dietary fiber-bound phenolic, and carotenoid compounds) metabolites of three maize types (white, red, and orange) from the Peruvian Andean race Cabanita at different maturity stages (milk-S1, dough-S2, and mature-S3) using targeted and untargeted methods. In addition, their antioxidant potential, and α-amylase and α-glucosidase inhibitory activities relevant for hyperglycemia management were investigated using in vitro models. Results revealed a high effect of the maize type and the maturity stage. All maize types had hydroxybenzoic and hydroxycinnamic acids in their free phenolic fractions, whereas major bound phenolic compounds were ferulic acid, ferulic acid derivatives, and p-coumaric acid. Flavonoids such as luteolin derivatives and anthocyanins were specific in the orange and red maize, respectively. The orange and red groups showed higher phenolic ranges (free + bound) (223.9-274.4 mg/100 g DW, 193.4- 229.8 mg/100 g DW for the orange and red maize, respectively) than the white maize (162.2-225.0 mg/100 g DW). Xanthophylls (lutein, zeaxanthin, neoxanthin, and a lutein isomer) were detected in all maize types. However, the orange maize showed the highest total carotenoid contents (3.19-5.87 μg/g DW). Most phenolic and carotenoid compounds decreased with kernel maturity in all cases. In relation to the primary metabolites, all maize types had similar fatty acid contents (linoleic acid > oleic acid > palmitic acid > α-linolenic acid > stearic acid) which increased with kernel development. Simple sugars, alcohols, amino acids, free fatty acids, organic acids, amines, and phytosterols declined along with grain maturity and were overall more abundant in white maize at S1. The in vitro functionality was similar among Cabanita maize types, but it decreased with the grain development, and showed a high correlation with the hydrophilic free phenolic fraction. Current results suggest that the nutraceutical characteristics of orange and white Cabanita maize are better at S1 and S2 stages while the red maize would be more beneficial at S3.

Spicy Food and Chili Peppers and Multiple Health Outcomes: Umbrella Review

Spicy foods and chili peppers contain the primary ingredient capsaicin, which has potential health benefits. However, their efficacy in some health outcomes is also fiercely disputed, and some side effects have been confirmed. To assess the quality and strength of the associations between spicy food and chili pepper consumption and different health outcomes. An umbrella review is performed in humans. Eleven systematic reviews and meta-analyses with a total of 27 findings are identified. The health effect of consuming spicy food and chili peppers is unclear. Furthermore, the characteristics and context of different world regions and populations should be carefully considered. Direct correlations exist in esophageal cancer, gastric cancer, and gallbladder cancer. However, negative connections are reported in metabolism, mortality, and cardiovascular disease. Dose-response analysis reveals a significant nonlinear relationship between gastric cancer risk and capsaicin intake. The consumption of spicy foods and chili peppers is typically safe. However, high-quality proof is available to confirm this conclusion.

The Inhibition of α-Glucosidase, α-Amylase and Protein Glycation by Phenolic Extracts of Cotoneaster bullatus, Cotoneaster zabelii, and Cotoneaster integerrimus Leaves and Fruits: Focus on Anti-Hyperglycemic Activity and Kinetic Parameters

Cotoneaster species have gained significant importance in traditional Asian medicine for their ability to prevent and treat hyperglycemia and diabetes. Therefore, in this study, some aspects of the beneficial health effects of hydromethanolic extracts of C. bullatus, C. zabelii, and C. integerrimus leaves and fruits were evaluated, including their influence on α-glucosidase, α-amylase, and nonenzymatic protein glycation. The activity was investigated in relation to the polyphenolic profile of the extracts determined by UV-spectrophotometric and HPLC-PDA-fingerprint methods. It was revealed that all leaf and fruit extracts are a promising source of biological components (caffeic acid pseudodepsides, proanthocyanidins, and flavonols), and the leaf extracts of C. bullatus and C. zabelii contain the highest levels of polyphenols (316.3 and 337.6 mg/g in total, respectively). The leaf extracts were also the most effective inhibitors of digestive enzymes and nonenzymatic protein glycation. IC50 values of 8.6, 41.8, and 32.6 µg/mL were obtained for the most active leaf extract of C. bullatus (MBL) in the α-glucosidase, α-amylase, and glycation inhibition tests, respectively. In the kinetic study, MBL was displayed as a mixed-type inhibitor of both enzymes. The correlations between the polyphenol profiles and activity parameters (|r| > 0.72, p < 0.05) indicate a significant contribution of proanthocyanidins to the tested activity. These results support the traditional use of Cotoneaster leaves and fruits in diabetes and suggest their hydrophilic extracts be promising in functional applications.

Strategies in synthetic design and structure-activity relationship studies of novel heterocyclic scaffolds as aldose reductase-2 inhibitors

Heterocyclic scaffolds of natural as well as synthetic origin provide almost all categories of drugs exhibiting a wide range of pharmacological activities, such as antibiotics, antidiabetic and anticancer agents, and so on. Under normal homeostasis, aldose reductase 2 (ALR2) regulates vital metabolic functions; however, in pathological conditions like diabetes, ALR2 is unable to function and leads to secondary diabetic complications. ALR2 inhibitors are a novel target for the treatment of retinopathy (cataract) influenced by diabetes. Epalrestat (stat), an ALR2 inhibitor, is the only drug candidate that was approved in the last four decades; the other drugs from the stat class were retracted after clinical trial studies due to untoward iatrogenic effects. The present study summarizes the recent development (2014 and onwards) of this pharmacologically active ALR2 heterocyclic scaffold and illustrates the rationale behind the design, structure-activity relationships, and biological studies performed on these molecules. The aim of the current review is to pave a straight path for medicinal chemists and chemical biologists, and, in general, to the drug discovery scientists to facilitate the synthesis and development of novel ALR2 inhibitors that may serve as lead molecules for the treatment of diseases related to the ALR2 enzyme.

An Ethnopharmaceutical Study on the Hypolipidemic Formulae in Taiwan Issued by Traditional Chinese Medicine Pharmacies

Globally, approximately one-third of ischemic heart diseases are due to hyperlipidemia, which has been shown to cause various metabolic disorders. This study was aimed to disassemble and analyze hypolipidemic formulae sold by traditional Chinese medicine (TCM) pharmacies. Using commonly used statistical parameters in ethnopharmacology, we identified the core drug combination of the hypolipidemic formulae, thereby exploring the strategy by which the Taiwanese people select hypolipidemic drugs. Most important of all, we preserved the inherited knowledge of TCM. We visited 116 TCM pharmacies in Taiwan and collected 91 TCM formulae. The formulae were mainly disassembled by macroscopical identification, and the medicinal materials with a relative frequency of citation (RFC) >0.2 were defined as commonly used medicinal materials. Subsequently, we sorted the information of medicinal materials recorded in the Pharmacopeia, searched for modern pharmacological research on commonly used medicinal materials using PubMed database, and visualized data based on the statistical results. Finally, the core hypolipidemic medicinal materials used in folk medicine were obtained. Of the 91 TCM formulae collected in this study, 80 traditional Chinese medicinal materials were used, belonging to 43 families, predominantly Lamiaceae. Roots were the most commonly used part as a medicinal material. There were 17 commonly used medicinal materials. Based on medicinal records in Pharmacopeia, most flavors and properties were warm and pungent, the majority traditional effects were “tonifying and replenishing” and “blood-regulating.” Besides, the targeted diseases searching from modern pharmacological studies were diabetes mellitus and dyslipidemia. The core medicinal materials consisted of Astragalus mongholicus Bunge and Crataegus pinnatifida Bunge, and the core formulae were Bu-Yang-Huan-Wu-Tang and Xie-Fu-Zhu-Yu-Tang. In addition, 7 groups of folk misused medicinal materials were found. Although these TCMs have been used for a long period of time, their hypolipidemic mechanisms remain unclear, and further studies are needed to validate their safety and efficacy.

Characterization of phenolics and discovery of α-glucosidase inhibitors in Artemisia argyi leaves based on ultra-performance liquid chromatography-tandem mass spectrometry and relevance analysis

Artemisia argyi leaves (AAL) has been widely used as herbal medicine and food supplement and in China and other Asian countries. The aim of this work is to qualitative and quantitative characterization of phenolic compounds in AAL and screening of natural product inhibitors of α-glucosidase from AAL. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was employed to rapid and comprehensive identification of phenolic compounds in AAL, and a total of thirty-three phenolic compounds were identified. High performance liquid chromatography with diode array detection (HPLC-DAD) was established and validated to simultaneously determinate ten main bioactive phenolics compounds in different batches of AAL samples. Meanwhile, the inhibitory capacities of different batches of AAL samples on α-glucosidase were evaluated. Then, relevance analysis, including grey relational analysis and Pearson correlation analysis were employed to investigate the correlations between the contents of phenolic compounds and α-glucosidase inhibitory activities, and discover the α-glucosidase inhibitors in AAL. The relevance analysis results indicated that three phenolic compounds, 3-caffeoylquinic acid, 3,4-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid could be potential α-glucosidase inhibitors in AAL. Moreover, the α-glucosidase inhibitory activities of the three phenolic compounds were validated by in vitro and in vivo experiments. The possible inhibiting effect of the three phenolic compounds on α-glucosidase was also explored by molecular docking analysis, and the results indicated that the binding of the three α-glucosidase inhibitors to α-glucosidase mainly by hydrogen bonds, hydrophobic forces and ionic bonds. The present research provided a deep insight into phenolic compounds and α-glucosidase inhibitory activities of AAL, and discovered the α-glucosidase inhibitors in AAL.

Biological Activities of Seven Medicinal Plants Used in Chiapas, Mexico

Seven medicinal plants from Chiapas, Mexico, used by Native Americans were analyzed, aiming to improve the understanding of their medicinal properties through the evaluation of various biological activities, i.e., bactericidal, antioxidant, α-glucosidase inhibition, and toxicity, to provide a scientific basis for the management of infectious and hyperglycemic diseases in the Mexican southeast. Plant extracts were obtained from Cordia dodecandra, Gaultheria odorata, Heliotropium angiospermum, Justicia spicigera, Leucaena collinsii spp. collinsii, Tagetes nelsonii, and Talisia oliviformis through maceration techniques using methanol and chloroform (1:1). Minimum Inhibitory Concentration (MIC) was employed to determine the antibacterial activity against Staphylococcus aureus, Enterobacter faecalis, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeuroginosa. The antiradical/antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays and antihemolytic activity using the 2,2’-Azobis(2-amidinopropane) dihydrochloride radical (APPH). The anti-α-glucosidase activity was evaluated in vitro through the chromogenic PNPG assay. The toxicity was assessed using the brine shrimp lethality assay. The highest antimicrobial activity was displayed by T. nelsonii, mainly against E. faecalis and P. aeuroginosa. The extracts of L. collinsii, J. spicigera, and T. nelsonii possess antioxidant properties with EC50 < 50 μg/mL. J. spicigera and T. nelsonii extracts showed the highest antihemolytic activity with IC50 < 14 μg/mL. T. nelsonii exhibited a remarkable inhibitor effect on the α-glucosidase enzyme and the greatest toxic effect on Artemia salina with IC50 = 193 ± 20 μg/mL and LD50 = 14 ± 1 μg/mL, respectively. According to our results, G. odorata, J. spicigera, T. nelsonii, and T. oliviformis extracts contained active antimicrobial compounds. At the same time, T. nelsonii stands to be a possible source of effective antineoplastic and antihyperglycemic compounds.

In Vitro Inhibitory Effects of Viburnum opulus Bark and Flower Extracts on Digestion of Potato Starch and Carbohydrate Hydrolases Activity

One of the effective treatments for diabetes is to reduce and delay the absorption of glucose by inhibition of α-amylase and α-glucosidase in the digestive tract. Currently, there is a great interest in natural inhibitors from various part of plants. In the present study, the phenolic compounds composition of V. opulus bark and flower, and their inhibitory effects on in vitro potato starch digestion as well as on α-amylase and α-glucosidase, have been studied. Bark and flower phenolic extracts reduced the amount of glucose released from potato starch during tree-stage simulated digestion, with IC50 value equal to 87.77 µg/mL and 148.87 µg/mL, respectively. Phenolic bark extract showed 34.9% and 38.4% more potent inhibitory activity against α-amylase and α-glucosidase, respectively, but the activity of plant extracts was lower than that of acarbose. Chlorogenic acid (27.26% of total phenolics) and (+)-catechin (30.48% of total phenolics) were the most prominent phenolics in the flower and bark extracts, respectively. Procyanidins may be responsible for the strongest V. opulus bark inhibitory activity against α-amylase, while (+)-catechin relative to α-glucosidase. This preliminary study provides the basis of further examination of the suitability of V. opulus bark compounds as components of nutraceuticals and functional foods with antidiabetic activity.

Exploration of the Interactions between Maltase–Glucoamylase and Its Potential Peptide Inhibitors by Molecular Dynamics Simulation

Diabetes mellitus, a chronic metabolic disorder, represents a serious threat to human health. The gut enzyme maltase–glucoamylase (MGAM) has attracted considerable attention as a potential therapeutic target for the treatment of type 2 diabetes. Thus, developing novel inhibitors of MGAM holds the promise of improving clinical management. The dipeptides, Thr-Trp (TW) and Trp-Ala (WA), are known inhibitors of MGAM; however, studies on how they interact with MGAM are lacking. The work presented here explored these interactions by utilizing molecular docking and molecular dynamics simulations. Results indicate that the active center of the MGAM could easily accommodate the flexible peptides. Interactions involving hydrogen bonds, cation-π, and hydrophobic interactions are predicted between TW/WA and residues including Tyr1251, Trp1355, Asp1420, Met1421, Glu1423, and Arg1510 within MGAM. The electrostatic energy was recognized as playing a dominant role in both TW-MGAM and WA-MGAM systems. The binding locations of TW/WA are close to the possible acid-base catalytic residue Asp1526 and might be the reason for MGAM inhibition. These findings provide a theoretical structural model for the development of future inhibitors.

Inhibition of human carbonyl reducing enzymes by plant anthrone and anthraquinone derivatives

Members of the aldo-keto reductase and short-chain dehydrogenase/reductase enzyme superfamilies catalyze the conversion of a wide range of substrates, including carbohydrates, lipids, and steroids. These enzymes also participate in the transformation of xenobiotics, inactivation of the cytostatics doxo- and daunorubicin, and play a role in the development of cancer. Therefore, inhibitors of such enzymes may improve therapeutic outcomes. Plant-derived compounds such as anthraquinones have been used for medicinal purposes for several centuries. In the current study, the inhibitory potential of selected anthrone and anthraquinone derivatives (from plants) was tested on six recombinant human carbonyl reducing enzymes (AKR1B1, AKR1B10, AKR1C3, AKR7A2, AKR7A3, CBR1) isolated from an Escherichia coli expression system. Overall, the least inhibition was observed with the anthrone derivative aloin, while IC50 values obtained with the anthraquinone derivatives (frangula emodin, aloe emodin, frangulin A, and frangulin B) and the aldo-keto reductase AKR1B10 were in the low micromolar range (3.5-16.6 μM). AKR1B1 inhibition was significantly weaker in comparison with AKR1B10 inhibition (IC50 values > 50 μM). The strongest inhibition was observed with the short-chain dehydrogenase/reductase CBR1. AKR7A2, AKR7A3, and AKR1C3 were not, or less inhibited by inhibitor concentrations of up to 50 μM. Analysis of the kinetic data suggests noncompetitive or uncompetitive inhibition mechanisms. The new inhibitors described here may serve as lead structures for the development of future drugs.

Effects of Mulberry Branch and Leaves Silage on Microbial Community, Rumen Fermentation Characteristics, and Milk Yield in Lactating Dairy Cows

This study investigated the effects of mulberry branch and leaves (MBL) silage on milk yield, ruminal fermentation, and bacteria composition in dairy cows. Thirty-six mid-lactation cows were selected and randomly allocated into three groups. The control group (C) was fed on a total mixed ratio (TMR) diet, while the experimental groups were fed on TMR supplemented with 5% (L) and 10% (H) MBL silage. The experiment lasted for eight weeks, including two weeks of adaption. The results showed that Group H had an increased milk yield, milk fat content (p < 0.05), and 4% feed conversion ratio (p = 0.10). In addition, rumen propionic acid was significantly increased (p < 0.05), while acetate/propionate was significantly decreased (p < 0.05) in the high MBL silage group. The microbiome analysis showed that Bacteroides, Firmicutes, and Proteobacteria were the predominant phyla. Compared with Group C, the abundance of Bacteroides was significantly decreased (p < 0.01), while the Firmicutes and Proteobacteria were increased but not significantly different in Groups L and H. Prevotella was significantly decreased (p < 0.05) in the MBL silage groups, and Succinivibrionaceae_UCG-001 was increased in Group H. The correlation analysis showed that eight bacterial species belonging to Firmicutes were positively correlated with propionic acid. However, four bacterial species belonging to the Bacteroides group were negatively correlated with propionic acid. In conclusion, feed supplementation with about 5–10% of MBL silage could modulate the rumen microbiota and fermentation, and increase the abundance of fiber-digesting, propionic acid synthesis and milk fat-related microorganisms, thus improving milk yield in dairy cows.

Anethum sowa Roxb. ex fleming: A review on traditional uses, phytochemistry, pharmacological and toxicological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Anethum sowa Roxb. ex Fleming (Syn. Peucedanum sowa Roxb. ex Fleming, Family: Apiaceae) is a pharmacologically important as aromatic and medicinal plant. Various parts of this plant are used in traditional medicine systems for carminative, uterine and colic pain, digestion disorder, flatulence in babies, appetite-stimulating agent and used to treat mild flue and cough. The essential oil is used for aromatherapy. It is also used as a spice for food flavouring and culinary preparations in many Asian and European countries.

AIM OF THE REVIEW

This review aims to provide a comprehensive and critical assessment from the reported traditional and pharmaceutical uses and pharmacological activities of the extracts, essential oil and phytoconstituents with emphasis on its therapeutic potential as well as toxicological evaluation of A. sowa.

MATERIALS AND METHODS

Online search engines such as SciFinder®, GoogleScholar®, ResearchGate®, Web of Science®, Scopus®, PubMed and additional data from books, proceedings and local prints were searched using relevant keywords and terminologies related to A. sowa for critical analyses.

RESULTS

The literature studies demonstrated that A. sowa possesses several ethnopharmacological activities, including pharmaceutical prescriptions, traditional applications, and spice in food preparations. The phytochemical investigation conducted on crude extracts has been characterized and identified various classes of compounds, including coumarins, anthraquinone, terpenoids, alkaloid, benzodioxoles, phenolics, polyphenols, phenolic and polyphenols, fatty acids, phthalides and carotenoids. The extracts and compounds from the different parts of A. sowa showed diverse in vitro and in vivo biological activities including antioxidant, antiviral, antibacterial, analgesic and anti-inflammatory, Alzheimer associating neuromodulatory, cytotoxic, anticancer, antidiabetes, insecticidal and larvicidal.

CONCLUSION

A. sowa is a valuable medicinal plant which is especially used in food flavouring and culinary preparations. This review summarized the pertinent information on A. sowa and its traditional and culinary uses, as well as potential pharmacological properties of essential oils, extracts and isolated compounds. The traditional uses of A. sowa are supported by in vitro/vivo pharmacological studies; however, further investigation on A. sowa should be focused on isolation and identification of more active compounds and establish the links between the traditional uses and reported pharmacological activities with active compounds, as well as structure-activity relationship and in vivo mechanistic studies before integrated into the medicine. The toxicological report confirmed its safety. Nonetheless, pharmacokinetic evaluation tests to validate its bioavailability should be encouraged.

Identification of α-amylase inhibitors from flavonoid fraction of Feronia elephantum and its integration with in-silico studies

Postprandial hyperglycemia is associated with an increase in blood glucose levels after a meal, which is further associated with various risk factors like cardiovascular diseases. α-amylase is a digestive enzyme and secreted by the salivary glands and pancreas, which helps to catalyze the hydrolysis of the internal α-1,4-glycosidic linkages in starch breaking them into smaller units. Hence, the present study is aimed to identify flavonoids from the fruit pulp of Feronia elephantum as α-amylase inhibitors via in-silico and in-vitro protocols. In-silico tools like ADVERPred, PubChem, MolSoft, Discovery studio 2019, and Autodock 4.0 were used to predict the information related to phytoconstituents, drug-likeness character, and probable side effects. In-vitro α-amylase inhibitory activity was performed with five different concentrations of flavonoid fraction of hydroalcoholic extract of the fruit pulp of Feronia elephantum using 1% starch solution and DNS reagent. Four flavonoids were identified from 25 bio-actives present in the fruit pulp of Feronia elephantum. Three bio-actives were predicted to possess a positive drug-likeness score, from which 5,4-dihydroxy3-3(3-methyl-but2-enyl)3,5,6-trimethoxy-flavone-7-O-β-d-Glucopyranoside was predicted to possess the highest drug-likeness score of 0.70. Vitexin and 5,4-dihydroxy3-3(3-methyl-but2-enyl)3,5,6-trimethoxy-flavone-7-O-β-d-Glucopyranoside were predicted to possess nephrotoxicity as an adverse effect. The percent inhibition of α-amylase by a flavonoid-rich fraction at 100 μg/ml was found to be 45.95% as compared to standard acarbose with 74.79% inhibition at 100 μg/ml. Further, docking studies predicted that vitexin possessed the highest binding affinity (binding energy - 7.98 kcal/mol) as compared to standard acarbose with binding energy - 5.24 kcal/mol. There were no significant side effects predicted, in-vitro α-amylase inhibitory activity of the flavonoid-rich fraction may be due to the presence of vitexin, predicted via in-silico molecular docking; further, which needs to be further validated via in-vivo protocols.

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.

A Prospective of Multiple Biopharmaceutical Activities of Procyanidins-Rich Uapaca togoensis Pax Extracts: HPLC-ESI-TOF-MS Coupled with Bioinformatics Analysis

The article reports the chemical composition, antioxidant, six key enzymes inhibitory and antimicrobial activities of two solvent extracts (water and methanol) of leaves and stem bark of Uapaca togoensis. For chemical composition, methanol extract of stem bark exhibited significant higher total phenolic (129.86 mg GAE/g) and flavanol (10.44 mg CE/g) contents. Methanol extract of leaves and water extract of stem bark showed high flavonoids (20.94 mg RE/g) and phenolic acid (90.40 mg CAE/g) content, respectively. In addition, HPLC-ESI-TOF-MS analysis revealed that U. togoensis was rich in procyanidins. The methanol and water extracts of stem bark had overall superior antioxidant activity; however, only methanol extract of stem bark showed higher inhibition of cholinesterase (AChE: 2.57 mg GALAE/g; BChE: 4.69 mg GALAE/g), tyrosinase (69.53 mg KAE/g) and elastase (2.73 mmol CE/g). Potent metal chelating ability was showed by water extract of leaves (18.94 mg EDTAE/g), higher inhibition of amylase was detected for water extracts of leaves (0.94 mmol ACAE/g) and stem bark (0.92 mmol ACAE/g). The tested extracts have shown wide-spectrum antibacterial properties and these effects have shown to be more effective against Aspergillus ochraceus, Penicillium funiculosum, Trichoderma viride, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. The results revealed that the antioxidant, enzyme inhibitory and antimicrobial activities depended on the extraction solvents and the parts of plant. Bioinformatics analysis on the 17 major compounds showed modulation of pathway associated with cancer. In brief, U. togoensis might be valuable as potential source of natural agents for therapeutic application.

Glycoside Hydrolases and Non-Enzymatic Glycation Inhibitory Potential of Viburnum opulus L. Fruit-In Vitro Studies

Phytochemicals of various origins are of great interest for their antidiabetic potential. In the present study, the inhibitory effects against carbohydrate digestive enzymes and non-enzymatic glycation, antioxidant capacity, and phenolic compounds composition of Viburnum opulus L. fruits have been studied. Crude extract (CE), purified extract (PE), and ethyl acetate (PEAF) and water (PEWF) fractions of PE were used in enzymatic assays to evaluate their inhibitory potential against α-amylase with potato and rice starch as substrate, α-glucosidase using maltose and sucrose as substrate, the antioxidant capacity (ABTS, ORAC and FRAP assays), antiglycation (BSA-fructose and BSA-glucose model) properties. Among four tested samples, PEAF not only had the highest content of total phenolics, but also possessed the strongest α-glucosidase inhibition, antiglycation and antioxidant activities. UPLC analysis revealed that this fraction contained mainly chlorogenic acid, proanthocyanidin oligomers and flavalignans. Contrary, the anti-amylase activity of V. opulus fruits probably occurs due to the presence of proanthocyanidin polymers and chlorogenic acids, especially dicaffeoylquinic acids present in PEWF. All V. opulus samples have an uncompetitive and mixed type inhibition against α-amylase and α-glucosidase, respectively. Considering strong anti-glucosidase, antioxidant and antiglycation activities, V. opulus fruits may find promising applications in nutraceuticals and functional foods with antidiabetic activity.

Antihyperglycemic and Antilipidemic Properties of a Tea Infusion of the Leaves from Annona cherimola Miller on Streptozocin-Induced Type 2 Diabetic Mice

The antihyperglycemic and antilipidemic effects of the tea infusion extracts of leaves from Annona cherimola Miller (IELAc-0.5, IELAc-1.5, and IELAc-3.0) were evaluated on normoglycemic (NG) and streptozocin-induced diabetic (STID) mice. In the acute test, IELAc-1.5 at 300 mg/kg bodyweight (bw) exhibited antihyperglycemic activity on STID mice since the first hour of treatment. Then, its antidiabetic potential was analyzed in a subchronic evaluation. IELAc-1.5 was able to reduce the blood glucose level, glycated hemoglobin (HbA1c), cholesterol (CHO), and triglycerides (TG); high-density lipoprotein (HDL) showed an increase at the end of treatment. IELAc-1.5 did not modify the urine profile at the end of the evaluation, and neither toxicity nor macroscopic organ damage were observed in acute and subchronic assays. In addition, a major flavonol glycoside present in the tea infusion extracts was identified using high-performance liquid chromatography with diode array detection (HPLC-DAD). The analysis of the tea infusion extracts by HPLC revealed that rutin was the major component. This study supports the use of tea infusions from Annona cherimola for the treatment of diabetes and suggests that rutin could be responsible, at least in part, for their antidiabetic properties.

Antidiabetic effect of Sophora pachycarpa seeds extract in streptozotocin-induced diabetic mice: a statistical evaluation

Undoubtedly, identification of the chemical composition of organic extracts or secondary metabolites of plant materials and evaluation of their potential bioactivity are among the main objectives of natural products-based investigations. In the present study, we report the chemical composition and antidiabetic activity of Sophora pachycarpa (Family Fabaceae) seeds extract (SPE) for the first time. First, the plant seeds were macerated in ethanol. The extract was subjected to analysis on a gas chromatography-mass spectrometry (GC-MS) system to identify the chemical composition. In vivo assay was run to evaluate the antidiabetic activity of the extract. Forty mice were divided into four groups, namely healthy mice, untreated diabetic mice, diabetic mice treated with metformin and diabetic mice treated with SPE. The antidiabetic activity of SPE was analyzed using three statistical methods, namely analysis of variance, K-means, and principal component analysis. According to GC-MS analysis, alkaloids of sophoridine, oleic acid, linoleic acid, and n-hexadecanoic acid were among the most abundant constituent components of SPE. The extract also exhibited a notable antidiabetic activity and remarkably decreased the levels of alkaline phosphatase (ALP), serum glutamic pyruvic transaminase (SGPT), and serum glutamic oxaloacetic transaminase (SGOT) enzymes. The statistical analyses revealed there are no significant differences between the ability of SPE and metformin in the regulation of fasting blood sugar level and liver enzymes (ALP, SGPT, and SGOT). A quinolizidine alkaloid, namely sophoridine, along with fatty acids, viz oleic, linoleic, and n-hexadecanoic acid, were characterized as the major compounds in S. tachycardia seeds extract. The plant extract was also found as a potent agent to reduce blood glucose and liver enzymes.

Antidiabetic and antimicrobial flavonoids from the twigs and roots of Erythrina subumbrans (Hassk.) Merr

The phytochemical investigation of the twig and root extracts of Erythrina subumbrans (Hassk.) Merr. (Fabaceae) resulted in the isolation and identification of a new pterocarpan, erythrinocarpan (1), along with 27 known compounds (2-28). All isolated compounds were evaluated for their antidiabetic, antimicrobial, and anti-inflammatory properties. Compounds 3, 8, 9, and 22 had α-glucosidase inhibitory activity with IC50 values of 13.4 ± 0.05, 24.5 ± 0.13, 29.0 ± 0.05, and 12.8 ± 0.14 μM, respectively, while compound 2 inhibited α-amylase activity with an IC50 value of 67.6 ± 1.12 μM. Compounds 22 and 24 inhibited glycation activity with the IC50 values of 36.9 ± 0.62 and 40.5 ± 0.37 μM, respectively. From cell-based assays, compound 27 showed the highest ability to induce glucose consumption (IC50 29.1 ± 0.86 μM) and glucose uptake (2.8-fold), and to inhibit nitric oxide (NO) production (IC50 52.5 ± 0.56 μM) without cell toxicity. Furthermore, compound 9 showed antimicrobial activities against Gram-positive bacteria and fungi with MIC values ranging from 2-4 μg/mL.

Indole-3-acetamides: As Potential Antihyperglycemic and Antioxidant Agents; Synthesis, In Vitro α-Amylase Inhibitory Activity, Structure-Activity Relationship, and In Silico Studies

Indole-3-acetamides (1-24) were synthesized via coupling of indole-3-acetic acid with various substituted anilines in the presence of coupling reagent 1,1-carbonyldiimidazole. The structures of synthetic molecules were elucidated through different spectroscopic techniques including electron ionization-mass spectroscopy (EI-MS), 1H-, 13C NMR, and high-resolution EI-MS (HREI-MS). These compounds were screened for their antihyperglycemic and antioxidant potentials. All compounds displayed good to moderate inhibition against α-amylase enzyme with IC50 values ranging between 1.09 ± 0.11 and 2.84 ± 0.1 μM compared to the standard acarbose (IC50 = 0.92 ± 0.4 μM). Compound 15 (IC50 = 1.09 ± 0.11 μM) was the most active compound of the series and exhibited good inhibition against α-amylase; in addition, this compound also exhibited good antioxidant potential with IC50 values of 0.35 ± 0.1 and 0.81 ± 0.25 μM in 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, respectively. The binding interactions of synthetic molecules with the enzyme's active site were confirmed via in silico studies. The current study had identified a number of lead molecules as potential antihyperglycemic and antioxidant agents.

Modeling and simulation in medical sciences: an overview of specific applications based on research experience in EMRI (Endocrinology and Metabolism Research Institute of Tehran University of Medical Sciences)

The concomitant use of various types of models (in silico, in vitro, and in vivo) has been exemplified here within the context of biomedical researches performed in the Endocrinology and Metabolism Research Institute (EMRI) of Tehran University of Medical Sciences. Two main research aeras have been discussed: the search for new small molecules as therapeutics for diabetes and related metabolic conditions, and diseases related to protein aggregation. Due to their multidisciplinary nature, the majority of these studies have needed the collaboration of different specialties. In both cases, a brief overview of the subject is provided through literature examples, and sequential use of these methods is described.

Forty-One Plant Extracts Screened for Dual Antidiabetic and Antioxidant Functions: Evaluating the Types of Correlation between -Amylase Inhibition and Free Radical Scavenging

Dysregulation of glucose homeostasis followed by chronic hyperglycemia is a hallmark of diabetes mellitus (DM), a disease spreading as a worldwide pandemic for which there is no satisfactory dietary treatment or cure. The development of glucose-controlling drugs that can prevent complications of DM, such as hyperglycemia and oxidative stress, which contribute to the impairment of the key physiological processes in the body, is of grave importance. In pursuit of this goal, this study screened 41 plant extracts for their antidiabetic and antioxidant activities by employing assays to test for α-amylase inhibition and free radical scavenging activity (FRSA) and by measuring glucose uptake in L6-GLUT4myc cells. While extracts of Rhus coriaria, Punica granatum, Olea europaea, Pelargonium spp., Stevia rebaudiana, and Petroselinum crispum demonstrated significant α-amylase inhibition, the extracts of Rhus coriaria and Pelargonium spp. also demonstrated increased FRSA, and the extract of Rhus coriaria stimulated glucose uptake. These natural extracts, which are believed to have fewer side effects because they are prepared from edible plants, interfere with the process in the small intestine that breaks down dietary carbohydrates into monosaccharide and disaccharide derivatives, and thereby suppress increases in diet-induced blood glucose; hence, they may have clinical value for type 2 diabetes management. The Pelargonium spp. and Rhus coriaria extracts demonstrated the highest antidiabetic and antioxidant activities. Both plants may offer valuable medical benefits, especially because they can be taken as dietary supplements by patients with diabetes and can serve as sources of new, natural-based antidiabetic drug candidates. The enhancement of cellular glucose uptake stimulated by Rhus coriaria extract could lead to the development of clinical applications that regulate blood glucose levels from within the circulatory system. Isolating bioactive substances from these plant extracts and testing them in diabetic mice will significantly advance the development of natural drugs that have both antidiabetic and free radical-scavenging properties, likely with lesser side effects.