GC-MS Analysis and Inhibitory Evaluation of Terminalia catappa Leaf Extracts on Major Enzymes Linked to Diabetes.
ABSTRACT: Terminalia catappa leaves are used in managing both diabetes mellitus and its complications in Southwest Nigeria. However, its inhibitory activity on enzymes implicated in diabetes is not very clear. This study investigated the in vitro inhibitory properties and mode of inhibition of T. catappa leaf extracts on enzymes associated with diabetes. The study also identified some bioactive compounds as well as their molecular interaction in the binding pocket of these enzymes. Standard enzyme inhibition and kinetics assays were performed to determine the inhibitory effects of aqueous extract (TCA) and ethanol extract (TCE) of T. catappa leaves on α-glucosidase and α-amylase activities. The phytoconstituents of TCA and TCE were determined using GC-MS. Molecular docking of the phytocompounds was performed using Autodock Vina. TCA and TCE were the most potent inhibitors of α-glucosidase (IC50 = 3.28 ± 0.47 mg/mL) and α-amylase (IC50 = 0.24 ± 0.08 mg/mL), respectively. Both extracts displayed a mixed mode of inhibition on α-amylase activity, while mixed and noncompetitive modes of inhibition were demonstrated by TCA and TCE, respectively, on α-glucosidase activity. The GC-MS analytic chromatogram revealed the presence of 24 and 22 compounds in TCE and TCA, respectively, which were identified mainly as phenolic compounds, terpenes/terpenoids, fatty acids, and other phytochemicals. The selected compounds exhibited favourable interactions with the enzymes compared with acarbose. Overall, the inhibitory effect of T. catappa on α-amylase and α-glucosidase may be ascribed to the synergistic action of its rich phenolic and terpene composition giving credence to the hypoglycaemic nature of T. catappa leaves.
Project description:As part of an ongoing search for new natural products from medicinal plants to treat type 2 diabetes, two new compounds, a megastigmane sesquiterpenoid sulfonic acid (1) and a new cyclohexylethanoid derivative (2), and seven related known compounds (3-9) were isolated from the leaves of Wedelia chinensis (Osbeck.) Merr. The structures of the compounds were conducted via interpretation of their spectroscopic data (1D and 2D NMR, IR, and MS), and the absolute configurations of compound 1 were determined by the modified Mosher's method. The MeOH extract of W. chinensis was found to inhibit ?-amylase and ?-glucosidase inhibitory activities as well as by the compounds isolated from this extract. Furthermore, compound 7 showed the strongest effect with IC50 values of 112.8?±?15.1??g/mL (against ?-amylase) and 785.9?±?12.7??g/mL (against ?-glucosidase). Compounds 1, 8, and 9 showed moderate ?-amylase and ?-glucosidase inhibitory effects. Other compounds showed weak or did not show any effect on both enzymes. The results suggested that the antidiabetic properties from the leaves of W. chinensis are not simply a result of each isolated compound but are due to other components such as the accessibility of polyphenolic groups to ?-amylase and ?-glucosidase activities.
Project description:Hyperglycemia is the hallmark of type 2 diabetes mellitus, and its prevention will go a long way in managing the disease and its associated complications. Reduction of postprandial hyperglycemia through retarding carbohydrates digesting enzymes is one of the major therapeutic approaches used in the management of diabetes.The aim of the present study was to investigate the antidiabetic and cytotoxic effects of Cissus cornifolia extracts in vitro.The α-amylase and α-glucosidase inhibitory activities of ethanolic and aqueous extracts of C. cornifolia root and leaves were investigated when the cytotoxic effects of these extracts were analyzed using MTT assay on human embryonic kidney (HEK 293) cell lines.The root ethanolic extract showed a mild α-amylase inhibitory activity with IC50 value of 22.75 ± 1.23 μg/ml, but strong α-glucosidase inhibitory activity with IC50 value 2.81 ± 0.97 μg/ml and the aqueous root extract indicated moderate inhibition for both α-amylase and α-glucosidase with IC50 values of 33.70 ± 3.75 and 37.48 ± 2.35 μg/ml, respectively. The ethanolic root extract was found nontoxic at tested concentrations on HEK 293 cell lines as confirmed by the MTT assay with 93% cell viability at the highest concentration (200 μg/ml) tested. However, the aqueous extracts (leaf and root) were found cytotoxic at concentrations above 50 μg/ml.Data of this study suggest that the root ethanolic extracts of C. cornifolia possesses moderate α-amylase, but strong α-glucosidase inhibitory activity in vitro and did not show significant cytotoxicity with the tested concentrations.Present study was conducted to examine effects of antidiabetic and cyctotoxic effects of Cissus conrnifolia root and leaves extracts in vitro. Data of this study suggest that the root ethanolic extract of C. cornifolia possesses mild to moderated antidiabetic activity via inhibiting carbohydrate digesting enzymes when no significant toxicity was observed with tested concentrations. Abbreviations used: alex: Aqueous leaf extract; arex: Aqueous root extract; CC: Cissus cornifolia; DNS: Dinitrosalicylic acid; DMSO: Dimethylsulfoxide; elex: Ethanolic leaf extract; erex: Ethanolic root extract; IDF: International Diabetes Federation; MEM: Minimum essential medium; NIDDM: Noninsulin-dependent diabetes mellitus; pNPG: Para-nitrophenyl glucopyranoside; SD: Standard deviation; T2D: Type 2 diabetes.
Project description:Context: Paederia foetida L. (Rubiaceae) is an edible plant distributed in Asian countries including Malaysia. Fresh leaves have been traditionally used as a remedy for indigestion and diarrhea. Several phytochemical studies of the leaves have been documented, but there are few reports on twigs. Objective: This study investigates the enzyme inhibition of P. foetida twig extracts and compound isolated from them. In addition, in silico molecular docking of scopoletin was investigated. Materials and methods: Plants were obtained from two locations in Malaysia, Johor (PFJ) and Pahang (PFP). Hexane, chloroform and methanol extracts along with isolated compound (scopoletin) were evaluated for their enzyme inhibition activities (10,000-0.000016 µg/mL). The separation and identification of bio-active compounds were carried out using column chromatography and spectroscopic techniques, respectively. In silico molecular docking of scopoletin with receptors (α-amylase and α-glucosidase) was carried out using AutoDock 4.2. Results: The IC50 values of α-amylase and α-glucosidase inhibition activity of PFJ chloroform extract were 9.60 and 245.6 µg/mL, respectively. PFP chloroform extract exhibited α-amylase and α-glucosidase inhibition activity (IC50 = 14.83 and 257.2 µg/mL, respectively). The α-amylase and α-glucosidase inhibitory activity of scopoletin from both locations had IC50 values of 0.052 and 0.057 µM, respectively. Discussion and conclusions: Separation of PFJ chloroform extract afforded scopoletin (1), stigmasterol (2) and γ-sitosterol (3) and the PFP chloroform extract yielded (1), (2), (3) and ergost-5-en-3-ol (4). Scopoletin was isolated from this species for the first time. In silico calculations gave a binding energy between scopoletin and α-amylase of -6.03 kcal/mol.
Project description:In this study, 5-amino-nicotinic acid derivatives (1-13) have been designed and synthesized to evaluate their inhibitory potential against ?-amylase and ?-glucosidase enzymes. The synthesized compounds (1-13) exhibited promising ?-amylase and ?-glucosidase activities. IC50 values for ?-amylase activity ranged between 12.17?±?0.14 to 37.33?±?0.02 µg/mL?±?SEM while for ?-glucosidase activity the IC50 values were ranged between 12.01?±?0.09 to 38.01?±?0.12 µg/mL?±?SEM. In particular, compounds 2 and 4-8 demonstrated significant inhibitory activities against ?-amylase and ?-glucosidase and the inhibitory potential of these compounds was comparable to the standard acarbose (10.98?±?0.03 and 10.79?±?0.17 µg/mL?±?SEM, respectively). In addition, the impact of substituent on the inhibitory potential of these compounds was assessed to establish structure activity relationships. Studies in molecular simulations were conducted to better comprehend the binding properties of the compounds. All the synthesized compounds were extensively characterized with modern spectroscopic methods including 1H-NMR, 13C-NMR, FTIR, HR-MS and elemental analysis.
Project description:Adansonia digitata (A. digitata) leaves serve as food and has several medicinal uses in many parts of the world. This study evaluated the influence of blanching on the phenolics composition, antioxidant activity, and inhibitory effect of methanol extract of A. digitata leaves on the activities of some key enzymes (?-amylase, ?-glucosidase, and aldose reductase) implicated in type 2 diabetes (T2D) in vitro. Reverse-phase HPLC analysis revealed that the leaves had appreciable levels of flavonoids and phenolic acids, including catechin, epicatechin, rutin, quercitrin, quercetin, kaempferol, and luteolin (flavonoids); gallic, chlorogenic, caffeic, and ellagic acids (phenolic acids). Blanching caused significant (P < 0.05) decrease in the flavonoids and phenolic acids contents; DPPH* (2,2 diphenyl-1-picrylhydrazyl radical) and ABTS*+ [2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) radical cation] scavenging ability; reducing power; and Fe2+-induced lipid peroxidation inhibitory capacity of the extract. Similarly, the inhibitory effect of the extract on the activities of ?-amylase, ?-glucosidase, and aldose reductase was significantly (P < 0.05) reduced due to blanching. Thus, A. digitata leaves extract could be effective for the management of T2D due to its flavonoids and phenolic acids content, antioxidant properties, and inhibitory potency on the activities of ?-amylase, ?-glucosidase, and aldose reductase. However, blanching militated against the levels of these functional attributes of the leaves and, therefore, may not be recommended for their optimal retention.
Project description:Inhibition of ?-amylase and ?-glucosidase by specified synthetic compounds during the digestion of starch helps control post-prandial hyperglycemia and could represent a potential therapy for type II diabetes mellitus. A new series of spiroheterocyclic compounds bearing oxindole/benzofuran/pyrrolidine/thiazolidine motifs were synthesized via a 1,3-dipolar cyclo-addition reaction approach. The specific compounds were obtained by reactions of chalcones having a benzo[b]furan scaffold (compounds 2a-f), with a substituted isatin (compounds 3a-c) and heterocyclic amino acids (compounds 4a,b). The target spiroindolone analogues 5a-r were evaluated for their potential inhibitory activities against the enzymes ?-amylase and ?-glucosidase. Preliminary results indicated that some of the target compounds exhibit promising ?-amylase and ?-glucosidase inhibitory activity. Among the tested spiroindolone analogues, the cycloadduct 5r was found to be the most active (IC50 = 22.61 ± 0.54 ?M and 14.05 ± 1.03 ?M) as ?-amylase and ?-glucosidase inhibitors, with selectivity indexes of 0.62 and 1.60, respectively. Docking studies were carried out to confirm the binding interaction between the enzyme active site and the spiroindolone analogues.
Project description:BACKGROUND:In this study, gallic acid (GA) and its polymeric form-tannic acid (TA) which are two phenolic acids found abundantly distributed in plant food sources were investigated for their influence on therapeutic properties of acarbose (AC) in vitro and in vivo in Drosophila melanogaster. METHODS:Combinations of AC and GA or TA were assessed for their alpha-glucosidase and alpha-amylase inhibitory effects as markers of anti-hyperglycemic properties, as well as their free radicals scavenging, Fe2+ chelating and malondialdehyde (MDA) inhibitory effects (in vitro). Furthermore, wild type D. melanogaster cultures were raised on diets containing AC, GA, TA and their various combinations for seven days. Thereafter, flies were homogenized and glucose concentrations, alpha-glucosidase and alpha-amylase activities, as well as reactive oxygen species (ROS) and total thiol levels were determined. RESULTS:The results showed that GA and TA up to 5 mg/ml significantly (p < 0.05) increased the enzymes' inhibitory effects and antioxidant properties of AC in vitro. Also, there was significant reduction in glucose concentration, enzyme activities and ROS level in D. melanogaster fed diets supplemented with phenolic acids and acarbose. CONCLUSIONS:These bioactive compounds-drug interactions provide useful information on improving the therapeutic properties of acarbose especially in its use as an antidiabetic drug.
Project description:In the present study, we isolated seven compounds from olive mill wastes (OMW), one of them being novel, and investigated their antidiabetic potential through inhibition of ?-glucosidase and ?-amylase enzymes. To assist the possible characterization of the mechanisms involved, we analyzed the inhibitory kinetics of the active compounds. Oleanolic acid 1, maslinic acid 2, 1-acetoxypinoresinol 3, and luteolin-7-O-?-d-glucoside 6 exhibited stronger inhibitory activity against both enzymes, with IC50 values less than or close to that of acarbose. Other compounds pinoresinol and hydroxytyrosol-containing compounds (hydroxytyrosol acetate 4, hydroxytyrosol 7, and the novel one, 3,4-dihydroxyphenyl-2-methoxyethanol 5) showed weak activity against both enzymes (IC50 > 500 ?M). Our findings show that, first, the esterification of C-1 of the furofuran ring is the key feature for the stronger activity of 1-acetoxypinoresinol 3 against both enzymes (IC50 = 13.9 and 313 ?M for ?-amylase and ?-glucosidase, respectively), as compared to pinoresinol; second, the oleanane skeletons of the triterpenes (1 and 2) are optimum for the ?-glucosidase and ?-amylase inhibitory activities, while the hydroxytyrosol moiety may be responsible for the weak activities of 4, 5, and 7. Additionally, kinetics analysis of 1, 6, and 3 revealed that they inhibit ?-glucosidase in mixed-type, noncompetitive, and uncompetitive mechanisms, respectively. We confirmed their mechanisms by measuring their affinity for the enzyme (K i), and they all (1, 6, and 3) had a higher affinity for the enzyme, K i > 1. This work adds more value to OMW for further studies as a potential source of lead antidiabetic compounds for the prevention and/or treatment of type 2 diabetes.
Project description:A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a-5h, have been synthesized, characterized by 1H-NMR and 13C-NMR, and evaluated for their in vitro ?-glucosidase and ?-amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both ?-glucosidase and ?-amylase. The IC50 of 5g against ?-glucosidase was 0.35917 ± 0.0189 µM (standard acarbose IC50 = 6.109 ± 0.329 µM), and the IC50 value of 5g against ?-amylase was 0.4379 ± 0.0423 µM (standard acarbose IC50 = 33.178 ± 2.392 µM). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of ?-glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 Å, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results.
Project description:Elevated blood glucose and increased activities of secreted phospholipase A2 (sPLA2) are strongly linked to coronary heart disease. In this report, our goal was to develop small heterocyclic compound that inhibit sPLA2. The title compounds were also tested against ?-glucosidase and ?-amylase. This array of enzymes was selected due to their implication in blood glucose regulation and diabetic cardiovascular complications. Therefore, two distinct series of quinoxalinone derivatives were synthesised; 3-[N'-(substituted-benzylidene)-hydrazino]-1H-quinoxalin-2-ones 3a-f and 1-(substituted-phenyl)-5H-[1,2,4]triazolo[4,3-a]quinoxalin-4-ones 4a-f. Four compounds showed promising enzyme inhibitory effect, compounds 3f and 4b-d potently inhibited the catalytic activities of all of the studied proinflammatory sPLA2. Compound 3e inhibited ?-glucosidase (IC50?=?9.99?±?0.18 µM); which is comparable to quercetin (IC50?=?9.93?±?0.66 µM), a known inhibitor of this enzyme. Unfortunately, all compounds showed weak activity against ?-amylase (IC50?>?200 µM). Structure-based molecular modelling tools were utilised to rationalise the SAR compared to co-crystal structures with sPLA2-GX as well as ?-glucosidase. This report introduces novel compounds with dual activities on biochemically unrelated enzymes mutually involved in diabetes and its complications.