New Alpha-Amylase Inhibitory Metabolites from Pericarps of Garcinia mangostana

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

Benzophenones-natural metabolites with great Hopes in drug discovery: structures, occurrence, bioactivities, and biosynthesis

Fungi have protruded with enormous development in the repository of drug discovery, making them some of the most attractive sources for the synthesis of bio-significant and structural novel metabolites. Benzophenones are structurally unique metabolites with phenol/carbonyl/phenol frameworks, that are separated from microbial and plant sources. They have drawn considerable interest from researchers due to their versatile building blocks and diversified bio-activities. The current work aimed to highlight the reported data on fungal benzophenones, including their structures, occurrence, and bioactivities in the period from 1963 to April 2023. Overall, 147 benzophenones derived from fungal source were listed in this work. Structure activity relationships of the benzophenones derivatives have been discussed. Also, in this review, a brief insight into their biosynthetic routes was presented. This work could shed light on the future research of benzophenones.

Inhibitory Potential of Different Bilberry (Vaccinium myrtillus L.) Extracts on Human Salivary α-Amylase

Recently, consumer preferences for bilberries have increased markedly. This fact is probably related to their natural constituents, such as phenolic compounds including anthocyanins and tannins, as well as the vitamins and minerals they contain. Phenolic compounds are known for their numerous beneficial effects on human health. Moreover, bilberry fruits have been shown to inhibit the activity of carbohydrate hydrolyzing enzymes, which can significantly decrease the postprandial increase in blood glucose levels. Thus, the aim of the present study is to investigate the inhibitory effect of Vaccinium myrtillus L. extracts on key enzyme α-amylase, linked to type 2 diabetes. No data have been published on the inhibitory properties of Vaccinium myrtillus L. fruits growing wild in Bulgaria against carbohydrate enzymes. Bilberry extracts were analyzed for total polyphenols, total anthocyanin content, antioxidant activity and their inhibitory properties against α-amylase. The contents of flavonols, anthocyanins and stilbenes were determined by HPLC analysis. The identified flavonols in the analyzed bilberry extracts were mainly represented by quercetin derivatives as rutinoside. The predominant anthocyanins for both aqueous and organic solvents were delphinidin-3-galactoside and malvidin-3-glucoside. The results revealed that bilberry extracts are effective inhibitors of α-amylase, with IC50 values from 20.8 to 194.8 μg GAE/mL. All the samples proved to have antioxidant activity measured by three different in vitro assays (FRAP, CUPRAC and DPPH). The inhibitory properties of V. myrtillus L. extracts may provide a new direction in the development and research of new pharmaceuticals for the suppression of postprandial hyperglycemia in diabetic patients.

Assessments of Alpha-Amylase Inhibitory Potential of Tagetes Flavonoids through In Vitro, Molecular Docking, and Molecular Dynamics Simulation Studies

Diabetes is a chronic fast-growing metabolic disorder that is characterized by high blood glucose levels. Tagetes minuta L. has been used as a traditional remedy for various illnesses for many years, and, furthermore, its oil is used in the perfume and flavor industries. T. minuta contains various metabolites, such as flavonoids, thiophenes, terpenes, sterols, and phenolics, with varied bioactivities. Flavonoids can inhibit carbohydrate-digesting enzymes, such as alpha-amylase, which is a convenient dietary strategy for controlling hyperglycemia. In the current investigation, the isolated flavonoids quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside), quercetagetin-7-O-β-D-glucopyranoside, quercetagetin-6-O-β-D-glucopyranoside, minutaside A, patuletin-7-O-β-D-glucopyranoside, quercetagetin-7-methoxy-6-O-β-D-glucopyranoside, tagenols A and B, quercetagetin-3,7-dimethoxy-6-O-β-D-glucopyranoside, patuletin, quercetin-3,6-dimethyl ether, and quercetin-3-methyl ether from T. minuta were assessed for their alpha-amylase inhibition (AAI) efficacy using an in vitro assay, as well as molecular docking, dynamics simulation, and ADMET analyses. Our findings show that quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside) (1), quercetagetin-7-O-β-D-glucopyranoside (2), quercetagetin-6-O-β-D-glucopyranoside (3), minutaside A (4), patuletin-7-O-β-D-glucopyranoside (5), and quercetagetin-7-methoxy-6-O-β-D-glucopyranoside (6) had a notable AAI capacity (IC₅₀s ranged from 7.8 to 10.1 μM) compared to acarbose (IC₅₀ 7.1 μM). Furthermore, these compounds with the highest binding affinity among the tested flavonoids revealed high docking scores for AA (ranging from -12.171 to 13.882 kcal/mol) compared to that of acarbose (-14.668 kcal/mol). In MDS, these compounds were observed to show maximum stability and the greatest binding free energy, suggesting that they may contend with native ligands. In addition, the ADMET analysis showed that these active compounds had a broad span of drug-like, pharmacokinetic, and physicochemical features and did not possess any considerable undesired effects. The current results suggest the potential of these metabolites as AAI candidates. However, further in vivo and mechanistic studies are warranted to specify the efficacy of these metabolites.

γ-Mangostin abrogates AINT-induced cholestatic liver injury: Impact on Nrf2/NF-κB/NLRP3/Caspase-1/IL-1β/GSDMD signalling

γ-Mangostin (γ-MN) is one of the abundant xanthones separated from Garcinia mangostana (Clusiaceae) pericarps that has been reported to have varied bioactivities such as neuroprotective, cytotoxic, antihyperglycemic, antioxidant, and anti-inflammation. Yet, its effect on cholestatic liver damage (CLI) has not been investigated. This study explored the protective activity of γ-MN against alpha-naphthyl isothiocyanate (ANIT)-induced CLI in mice. The results showed that γ-MN protected against ANIT-induced CLI as indicated by reduced serum levels of hepatic injury parameters (e.g., ALT, AST, γ-GT, ALP, LDH, bilirubin, and total bile acids). ANIT-induced pathological lesions were improved in γ-MN pre-treated groups. γ-MN exerted potent antioxidant effects as it lowered the parameters of lipid peroxidation (4-HNE, PC, and MDA) and intensified the content and activity of antioxidants (TAC, GSH, GSH-Px, GST, and SOD) in the hepatic tissue. Furthermore, γ-MN enhanced the signalling of Nrf2/HO-1 as it augmented the mRNA expression of Nrf2/downstream genes (HO-1/GCLc/NQO1/SOD). The binding capacity and the immuno-expression of Nrf2 were also increased. γ-MN showed anti-inflammatory capacity as it suppressed the activation of NF-κB signalling, it decreased mRNA expression and levels of NF-κB/TNF-α/IL-6 and the immuno-expression of NF-κB/TNF-α. In addition, γ-MN inhibited the activation of NLRP3 inflammasome as it lowered the mRNA expression of NLRP3/caspase-1/IL-1β along with their levels as well as the immuno-expression of caspase-1/IL-1β. γ-MN also reduced the level of the pyroptotic parameter GSDMD. Collectively, this study demonstrated the potent hepatoprotective potential of γ-MN against CLI which was linked to its ability to potentiate Nrf2/HO-1 and to offset NF-κB/NLRP3/Caspase-1/IL-1β/GSDMD. Hence, γ-MN may be suggested as a new candidate for cholestatic patients.

Comparative anti-Diabetic potential of phytocompounds from Dr. Duke's phytochemical and ethnobotanical database and standard antidiabetic drugs against diabetes hyperglycemic target proteins: an in silico validation

In the current investigation, the antidiabetic potential of 40 phytocompounds from Dr. Dukes phytochemical and ethanobotanical database and three antidiabetic pharmaceuticals from the market comparatively validated against hyperglycemic target proteins. Silymarin, proanthocyanidins, merremoside, rutin, mangiferin-7-O-beta-glucoside, and gymnemic acid exhibited good binding affinity toward protein targets of diabetes among the 40 phytocompounds from Dr.Dukes database over three chosen antidiabetic pharmaceutical compounds. Further these phytocompounds and sitagliptin are validated for its ADMET and bioactivity score to screen its pharmacological and pharmacokinetics properties. Silymarin, proanthocyanidins, rutin along with sitagliptin screened for DFT analysis found that phytocompounds have great Homo-Lumo orbital energies over commercial pharmaceutical sitagliptin. Finally, four complexes of alpha amylase-silymarin, alpha amylase-sitagliptin, aldose reductase-proanthocyanidins, and aldose reductase-sitagliptin screened for MD simulation and MMGBSA analysis, results shown that the phytocompounds silymarin and proanthocyanidins have strong affinities for binding to the binding pockets of alpha amylase and aldose reductase respectively over antidiabetic pharmaceuticals. Our current study proven proanthocyanidins and silymarin act as novel antidiabetic compounds toward diabetic target protein but it require clinical trial to evaluate its clinical pertinence toward diabetic target proteins.Communicated by Ramaswamy Sarma.

Mangosteen Metabolites as Promising Alpha-Amylase Inhibitor Candidates: In Silico and In Vitro Evaluations

Diabetes is a chronic metabolic disorder characterized by raised glucose levels in the blood, resulting in grave damage over time to various body organs, including the nerves, heart, kidneys, eyes, and blood vessels. One of its therapeutic treatment approaches involves the inhibition of enzymes accountable for carbohydrate digestion and absorption. The present work is aimed at evaluating the potential of some reported metabolites from Garcinia mangostana (mangosteen, Guttiferae) as alpha-amylase inhibitors. Forty compounds were assessed for their capacity to inhibit alpha-amylase using in silico studies as well as in vitro assays. Molecular docking was carried out to analyze their binding capacities in the 3D structure of alpha-amylase (PDB ID: 4GQR). Among the tested compounds, 6-O-β-D-glucopyranosyl-2,4,6,3',4',6'-hexahydroxybenzophenone (8), aromadendrin-8-C-glucoside (5), epicatechin (6), rhodanthenone (4), and garcixanthone D (40) had a high XP G.score and a Glide G.score of -12.425, -11.855, -11.135, and -11.048 Kcal/mol, respectively. Compound 8 possessed the XP and Glide docking score of -12.425 Kcal/mol compared to the reference compounds myricetin and acarbose which had an XP and Glide docking score of -12.319 and 11.201 Kcal/mol, respectively. It interacted through hydrogen bond formations between its hydroxyl groups and the residues His 101, Asp 197, Glu 233, Asp 300, and His 305, in addition to water bridges and hydrophobic interactions. Molecular mechanics-generalized born surface area (MM-GBSA) was used to calculate the binding free energy and molecular dynamic studies that indicated the stability of the alpha-amylase-compound 8 complex during the 100 ns simulation in comparison with myricetin- and acarbose-alpha-amylase complexes. Additionally, the in vitro alpha-amylase inhibition assay findings validated the in silico study's findings. This could further validate the potential of G. mangostana as a candidate for diabetes management.

Garcixanthone E and Garcimangophenone C: New Metabolites from Garcinia mangostana and Their Cytotoxic and Alpha Amylase Inhibitory Potential

Garcinia mangostana (Clusiaceae) is a rich pool of metabolites with diversified bioactivities. A new xanthone, garcixanthone E (1), and a new benzophenone, rhamnoside, as well as garcimangophenone C (9) together with garcinone E (2), α-mangostin (3), γ-mangostin (4), garcinone C (5), garcixanthone C (6), gartanin (7), and 2,4,6,3',5'-pentahydroxybenzophenone (8) were purified from G. mangostana EtOAc extract. Their structural verification was accomplished utilizing assorted spectral tools and relating to the literature. The in vitro cytotoxic potential versus MCF-7, A549, and HCT-116 cell lines demonstrated the moderate potential of 1 (IC₅₀s 8.5, 5.4, and 5.7 µM, respectively) in comparison to doxorubicin (IC₅₀s 0.18, 0.6 and 0.2 µM, respectively) using a sulforhodamine B (SRB) assay. Additionally, 1 and 9 had AAI (α-amylase inhibition) with IC₅₀s 17.8 and 12.9 µM, respectively, compared to acarbose (IC₅₀ 6.7 µM). Further, their AAI mechanisms were inspected utilizing molecular-docking evaluation by employing the crystal structure of the human α-amylase (PDB-ID: 5EOF). Compound 9 possessed a reasonable docking score of -7.746 kcal/mol compared with the native ligand 7JR which had a docking score of -9.932 kcal/mol. These results could further provide new insight into the potential usage of G. mangostana as a functional food for regulating postprandial hyperglycemia via suppressing AA.

Alpha-Mangostin as a New Therapeutic Candidate for Concanavalin A-Induced Autoimmune Hepatitis: Impact on the SIRT1/Nrf2 and NF-κB Crosstalk

Alpha-mangostin (α-MN) is a xanthone obtained from Garcinia mangostana that has diverse anti-oxidative and anti-inflammatory potentials. However, its pharmacological activity against autoimmune hepatitis (AIH) has not been investigated before. Concanavalin A (Con A) was injected into mice to induce AIH and two doses of α-MN were tested for their protective effects against Con A-induced AIH. The results demonstrated the potent hepatoprotective activity of α-MN evidenced by a remarkable decrease of serum indices of the hepatic injury and amendment of the histological lesions. α-MN significantly attenuated the level and immuno-expression of myeloperoxidase (MPO) indicating a decrease in the neutrophil infiltration into the liver. Additionally, the recruitment of the CD4+ T cell was suppressed in the α-MN pre-treated animals. α-MN showed a potent ability to repress the Con A-induced oxidative stress evident by the reduced levels of malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and protein carbonyl (PC), as well as the enhanced levels of antioxidants as the reduced glutathione (GSH), superoxide dismutase (SOD), and total antioxidant capacity (TAC). The ELISA, RT-PCR, and IHC analyses revealed that α-MN enhanced the sirtuin1/nuclear factor erythroid 2 related factor-2 (SIRT1/Nrf2) signaling and its downstream cascade genes concurrently with the inhibition of the nuclear factor kappa B (NF-κB) and the inflammatory cytokines (tumor necrosis factor-alpha and interleukine-6) signaling. Taken together, these results inferred that the hepatoprotective activity of α-MN could prevent Con A-induced AIH through the modulation of the SIRT1/Nrf2/NF-κB signaling. Hence, α-MN may be considered as a promising candidate for AIH therapy.

Ethnobotanical Uses, Phytochemical Composition, Biosynthesis, and Pharmacological Activities of Carpesium abrotanoides L. (Asteraceae)

Carpesium abrotanoides L. (Asteraceae) is a medicinal plant with immense therapeutic importance and bioactivities. It is commonly encountered in various Asian regions. It has numerous ethnomedicinal uses for curing diverse ailments such as toothache, stomach ulcer, boils, tonsillitis, bronchitis, bacterial infection, bruises, swelling, virus infection, fever, and amygdalitis, as well as an anthelmintic versus round-, tape-, hook-, and pinworms. Different classes of phytoconstituents such as sesquiterpenes, sesquiterpene dimers, monoterpenes, and nitrogenous compounds have been reported from this plant. These phytoconstituents have proved to possess anti-inflammatory, cytotoxic, antimicrobial, and insecticidal capacities. The present review aims to summarize all published data on C. abrotanoides including traditional uses, phytoconstituents, bioactivities, and toxicological aspects, as well as the synthesis and biosynthesis of its metabolites through an extensive survey on various databases and various publishers. These reported data could draw the attention of various natural-metabolite-interested researchers and medicinal chemists towards the development of this plant and/or its metabolites into medicine for the prevention and treatment of certain illnesses. Despite the diverse traditional uses of C. abrotanoides, there is a need for scientific evidence to support these claims. Clinical trials are also required to further assure these data and validate this plant utilization in treating several diseases.

Multitarget Action of Xanthones from Garcinia mangostana against α-Amylase, α-Glucosidase and Pancreatic Lipase

Digestive enzymes such α-amylase (AA), α-glucosidase (AG) and pancreatic lipase (PL), play an important role in the metabolism of carbohydrates and lipids, being attractive therapeutic targets for the treatment of type 2 diabetes and obesity. Garcinia mangostana is an interesting species because there have been identified xanthones with the potential to inhibit these enzymes. In this study, the multitarget inhibitory potential of xanthones from G. mangostana against AA, AG and PL was assessed. The methodology included the isolation and identification of bioactive xanthones, the synthesis of some derivatives and a molecular docking study. The chemical study allowed the isolation of five xanthones (1–5). Six derivatives (6–11) were synthesized from the major compound, highlighting the proposal of a new solvent-free methodology with microwave irradiation for obtaining aromatic compounds with tetrahydropyran cycle. Compounds with multitarget activity correspond to 2, 4, 5, 6 and 9, highlighting 6 with IC₅₀ values of 33.3 µM on AA, 69.2 µM on AG and 164.4 µM on PL. Enzymatic kinetics and molecular docking studies showed that the bioactive xanthones are mainly competitive inhibitors on AA, mixed inhibitors on AG and non-competitive inhibitors on PL. The molecular coupling study established that the presence of methoxy, hydroxyl and carbonyl groups are important in the activity and interaction of polyfunctional xanthones, highlighting their importance depending on the mode of inhibition.

Effects of "Bacuri" Seed Butter (Platonia insignis Mart.), a Brazilian Amazon Fruit, on Oxidative Stress and Diabetes Mellitus-Related Parameters in STZ-Diabetic Rats

This study aimed to investigate the effects of oral administration of Platonia insignis Mart. ("bacuri") seed butter (BSB) on oxidative stress and diabetes mellitus-related parameters in streptozotocin-induced (STZ) diabetic rats. Diabetes mellitus was induced in female Wistar rats (180-250 g) by the intraperitoneal administration of STZ (45 mg/kg, b.w). BSB (25, 50, and 100 mg/kg) was administered to animals for four weeks. The effect on weight gain, food intake, blood glucose, glycated hemoglobin, hepatic transaminases, plasma and liver TBARS and MPO activity, erythrocyte SOD activity, non-protein sulfhydryl groups (SH-NP), and histopathology of the liver tissue was investigated. BSB at the dose of 100 mg/kg had a positive effect on the reduction in glycated hemoglobin percentage and increased albumin concentration, as well as decreased ALT and AST levels and increased SH-NP liver levels in treated animals compared to normal control rats. Moreover, BSB had no effects on weight gain, food intake, and fasting glucose. Thus, the BSB presented marked properties in improvement of hepatic antioxidant defenses, which demonstrates BSB as a potential hepatoprotective agent in metabolic disorders.