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Role of Natural Agents in the Management of Diabetes
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Monika Elżbieta Jach, Anna Serefko
The hypoglycemic effect of hot water and methanol extracts of L. speciosa has been revealed in both numerous animal models and several human studies. Some studies are focused on corosolic acid originated from banaba leaves as a main bioactive substance responsible for antidiabetic properties. In these studies, purified corosolic acid is used as an isolate with an organic solvent (10 mg/30 days), and corosolic acid as a constituent of standardized banaba extracts (60 mg comprising 10 mg corosolic acid/2 weeks) (Park et al., 2011; Ulbricht et al., 2007). In other studies, there are ellagitannins in water-soluble fractions, which might have an activity similar to insulin, and tannins which have the antioxidant and glucose regulatory properties (Klein et al., 2007).
Inhibiting the Absorption of Dietary Carbohydrates and Fats with Natural Products
Published in Christophe Wiart, Medicinal Plants in Asia for Metabolic Syndrome, 2017
Ellagitannins in the fruits of Punica granatum L. inhibit in vitro the intestinal enzymes in charge of carbohydrate and triglyceride absorption. Methanol extract from seeds at a concentration of 2.5 mg/mL inhibited α-amylase activity by 94.5% in vitro (IC50: 1.1 mg/mL; acarbose: 1.3 μg/mL).96 Methanol extract from husk of Punica granatum L. seeds at a concentration of 2.5 mg/mL inhibited porcine pancreatic lipase by 100% in vitro (IC50: 0.1 mg/mL; orlistat: 0.1 ng/mL).96 Punicalagin, punicalin, and ellagic acid isolated from Punica granatum L. inhibited in vitro rat α-glucosidase with IC50 values of 140.2, 191.4, and 380 μmol/L, respectively.97 Methanol fractions of flowers of Punica granatum L. inhibited the enzymatic activity of recombinant human maltase–glucoamylase, rat maltase, and rat sucrase with IC50 values equal to 567, 87, and 324 μg/mL.98 In the same experiment, a methanol fraction of arils inhibited the enzymatic activity of recombinant human maltase–glucoamylase, rat maltase, and rat sucrase with IC50 values equal to 393.3, 527, and 486 μg/mL, respectively.98 From the methanol fraction of aril, oenothein B and punicalagin inhibited human maltase–glucoamylase, rat maltase, and rat sucrase with IC50 values equal to 174, 290, 213, 305, 535, and 369 μM, respectively.98 Consumption fruits’ juice of Punica granatum L. could be of value for metabolic syndrome.
Plant Phenolics
Published in Ruth G. Alscher, John L. Hess, Antioxidants in Higher Plants, 2017
Investigations of the biogenesis of gallo- and ellagitannins have largely focused upon the enzymology accompanying β-glucopentagallin 17 formation, using cell-free preparations from oak (Quercus robur) leaves,13 which also synthesize Type Β ellagitannins. With this biological system, the first enzymatic step in gallotannin biogenesis involves formation of ß-glucogallin 14, using both gallic acid 1 and UDP-D glucose as substrates. The ß-glucogallin 14 then undergoes an enzymatically catalyzed "disproportionation" to form 1,6-digalloylglucose 18 (Figure 3A). Additional galloyl moieties are added at C-2, C-3, and C-4. again using β-glucogallin 14 as a co-substrate and galloyl donor. Although not yet unambiguously established, it is expected that specific enzymes are required for each galloylation step.
Ellagic acid protects against non-alcoholic fatty liver disease in streptozotocin-diabetic rats by activating AMPK
Published in Pharmaceutical Biology, 2022
Jozaa Z. ALTamimi, Ghedeir M. Alshammari, Nora A. AlFaris, Reham I. Alagal, Dalal H. Aljabryn, Norah A. Albekairi, Mahmoud Ahmad Alkhateeb, Mohammed Abdo Yahya
Ellagic acid is a polyphenol abundant in various fruits, including strawberries, pomegranate, guava, walnuts, almonds, and green tea in the form of hydrolyzable tannins called ellagitannins (Evtyugin et al. 2020). In the intestine, ellagitannins are metabolized to EA, which is metabolized into more absorbable metabolites called urolithin, which may mediate its pharmacological effects (Djedjibegovic et al. 2020). At the clinical and experimental levels, EA possessed several pharmacological health benefits, including acting as an anticarcinogenic, antiviral, anti-inflammatory, antibacterial, antimalarial, antidiabetic, antianxiety, and antiatherogenic molecule (Goswami et al. 2014; Ayhanci et al. 2016; Seo et al. 2016; Polce et al. 2018; Aslan et al. 2020). EA is a potent hepatoprotective, nephroprotective, neuroprotective, and cardioprotective agent due to its well-reported antioxidant, anti-inflammatory, and anti-apoptotic effects (Kannan and Quine 2013; Goswami et al. 2014; Polce et al. 2018, Zhou et al. 2019). Indeed, EA prevented liver damage in several animal models, including, at least, alcohol, carbon tetrachloride (CCl4) cisplatin, cyclosporine, paracetamol, and HFD-induced diabetic rats.
The effect of leech extracts on endothelial cell coagulation-related factors and endothelial dysfuction-related molecules
Published in Clinical and Experimental Hypertension, 2019
Lixu Xu, Xue Li, E Zhang, Hao Liang, Weiting Li, Shangyi Wang, Shuliang Song, Aiguo Ji
In order to simulate possible gastrointestinal enzymatic hydrolysis of leeches, we used pepsin, trypsin, lipase, protease, and amylase four common enzymes in the human gastrointestinal tract (31,32), to prepare enzymatic extracts of leech. Using these enzymes, we obtained 4 different extracts: LP, PHL, PTHL and CEHL. It has been found that the human gut microbiota metabolites of ellagitannin-rich plant materials have anti-inflammatory effects (33). On the contrary, Haiser et al. found that intestinal bacteria can cause inactivation of digoxin drugs (34). Considering the ability of gut microbes to metabolize oral drugs prior to their absorption into the blood, we also metabolized PHL and PTHL with Lactobacillus, a common intestinal bacteria (35), and detected the anticoagulation activities of 4 Lactobacillus metabolites: MRS, MRS-1, MRS-2, and MRS-3.
Inhibition of protein phosphatase-1 and -2A by ellagitannins: structure-inhibitory potency relationships and influences on cellular systems
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Zoltán Kónya, Bálint Bécsi, Andrea Kiss, Dániel Horváth, Mária Raics, Katalin E. Kövér, Beáta Lontay, Ferenc Erdődi
The above data indicate that the influence of polyphenolic compounds on protein phosphatases in vitro and in vivo are quite complex which deserves further attentions in at least two respects that are aimed in our present study: (i) to assay the relationship between the structure of the ellagitannin family of polyphenols15 and their phosphatase inhibitory potency. Ellagitannins have been considered major components of plants and fruits with antioxidants, antiviral, and anticancer activities16; therefore we aim: (ii) to find the relevance of the physiological influence of polyphenols to their phosphatase inhibitory potency. We assayed five ellagitannins (structure and names are shown in Figure 1) on the activity of PP1c and PP2Ac, and the cellular effects of some of these derivatives were also analysed. Our results suggest that there is a structural dependence of the phosphatase inhibitory features of ellagitannins, and their selectivity for inhibition of PP1 over PP2A is quite high. Moreover, we also found that the two most potent inhibitors (tellimagrandin I and mahtabin A) have diverse effects on the survival of HeLa cells and on the exocytosis of cortical synaptosomes.