Castalin

Tannins inhibit SARS-CoV-2 through binding with catalytic dyad residues of 3CL(pro) : An in silico approach with 19 structural different hydrolysable tannins.[Pubmed:32783247]

J Food Biochem. 2020 Aug 11:e13432.

Coronavirus epidemic 2019 (COVID-19), instigated by SARS-CoV-2 virus, is recently raising worldwide and inspiring global health worries. The main 3-chymotrypsin-like cysteine protease (3CL(Pro) ) enzyme of SARS-CoV-2, which operates its replication, could be used as a medication discovery point. We therefore theoretically studied and docked the effects of 19 hydrolysable tannins on SARS-CoV-2 by assembling with the catalytic dyad residues of its 3CL(pro) using molecular operating environment (MOE 09). Results discovered that pedunculagin, tercatain, and Castalin intensely interacted with the receptor binding site and catalytic dyad (Cys145 and His41) of SARS-CoV-2. Our analyses estimated that the top three hits might serve as potential inhibitor of SARS-CoV-2 leading molecules for additional optimization and drug development process to combat COVID-19. This study unleashed that tannins with specific structure could be utilized as natural inhibitors against COVID-19. PRACTICAL APPLICATIONS: The 3CL(Pro) controls SARS-CoV-2 copying and manages its life series, which was targeted in case of SARS-CoV and MERS-CoV coronavirus. About 19 hydrolysable tannins were computed against 3CL(pro) of SARS-CoV-2. Pedunculagin, tercatain, and Castalin interacted with Cys145 and His41 of SARS-CoV-2-3CL(pro) . Pedunculagin-SARS-CoV-2-3CL(pro) remain stable, with no obvious fluctuations. We predicted that the understandings gained in the current research may evidence valued for discovering and unindustrialized innovative natural inhibitors for COVID-19 in the nearby future.

Subcritical Water Extraction of Chestnut Bark and Optimization of Process Parameters.[Pubmed:32560152]

Molecules. 2020 Jun 16;25(12). pii: molecules25122774.

The aim of the work was the optimization of the subcritical water extraction process of chestnut bark using Box-Behnken response surface methodology. The influence of process parameters, such as temperature, extraction time and solvent-solid ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity has been investigated. The identified compounds were ellagic and gallic acids, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin, vescalin and Castalin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). Finally, the optimal process conditions for obtaining the bark extract highly rich in ellagic acid and with satisfactory levels of total phenols and total tannins have been determined.

Anti-Herpes Simplex Virus Type 1 Activity of Specially Selected Groups of Tannins.[Pubmed:30134445]

Drug Res (Stuttg). 2019 Jul;69(7):374-373.

Anti-herpes simplex virus (HSV-1) activity of 9 ellagitannins, including 6 natural compounds (Castalin, vescalin, acutissimin A, epiacutissimins A and B, mongolicain) and 3 vescalagin synthetic derivatives (VgSBuSH, VgSOctSH, VgOMe), and 13 gallotannin-type compounds [Gal-01A, Gal-01B, Gal-02A, Gal-02B, Gal-03M, Gal-04A, Gal-04B, Gal-05M, Gal-07, Gal-08, Gal-09, Gal-11M (tannic acid), as well as Gal-12 (gallic acid), Gal-13 and Gal-14 (ellagic acid)] were examined in MDBK monolayer cell culture. Their antiviral activity was determined by the cytopathic effect (CPE) inhibition test and their cytotoxicity was evaluated through the neutral red uptake assay. In general, the series of ellagitannins showed a significantly stronger activity against HSV-1 replication than that of the gallotannins. Six of the tested ellagitannins manifested a well-pronounced activity: epiacutissimin B (selectivity index, SI>60.6), epiacutissimin A (SI>55.5), acutissimin A (SI>34.8), mongolicain (SI>32.5), VgSBuSH (SI>24.6) and VgOMe (SI>22.0). Four gallotannin-type compounds inhibited the replication of HSV-1 at a lower but still significant extent: Gal-04B (SI>35.7), Gal-04A (SI>28.5), Gal-11M (tannic acid) (SI>25) and Gal-05M (SI=15.6).

Structural Revisions in Natural Ellagitannins.[Pubmed:30061530]

Molecules. 2018 Jul 30;23(8). pii: molecules23081901.

Ellagitannins are literally a class of tannins. Triggered by the oxidation of the phenolic parts on beta-pentagalloyl-d-glucose, ellagitannins are generated through various structural conversions, such as the coupling of the phenolic parts, oxidation to highly complex structures, and the formation of dimer and lager analogs, which expand the structural diversity. To date, more than 1000 natural ellagitannins have been identified. Since these phenolic compounds exhibit a variety of biological activities, ellagitannins have potential applications in medicine and health enhancement. Within the context of identifying suitable applications, considerations need to be based on correct structural features. This review describes the structural revisions of 32 natural ellagitannins, namely alnusiin; alnusnin A and B; castalagin; Castalin; casuarinin; cercidinin A and B; chebulagic acid; chebulinic acid; corilagin; geraniin; isoterchebin; nobotanin B, C, E, G, H, I, J, and K; punicalagin; punicalin; punigluconin; roxbin B; sanguiin H-2, H-3, and H-6; stachyurin; terchebin; vescalagin; and vescalin. The major focus is on the outline of the initial structural determination, on the processes to find the errors in the structure, and on the methods for the revision of the structure.

alpha-Glucosidase inhibition and antioxidant activity of an oenological commercial tannin. Extraction, fractionation and analysis by HPLC/ESI-MS/MS and (1)H NMR.[Pubmed:27542449]

Food Chem. 2017 Jan 15;215:50-60.

Two batches of the oenological tannin Tan'Activ R, (toasted oak wood - Quercus robur), were extracted with ethanol. A fractionation on XAD-16 afforded four fractions for each extract. Extracts and fractions were evaluated for antioxidant activity (DPPH), polyphenol content (GAE) and yeast alpha-glucosidase inhibitory activity. Comparable results were obtained for both columns, fractions X1B and X2B showing the highest antioxidant activity. Fractions X1C and X2C notably inhibited alpha-glucosidase, with IC50=9.89 and 8.05mug/mL, respectively. Fractions were subjected to HPLC/ESI-MS/MS and (1)H NMR analysis. The main phenolic constituents of both X1B and X2B were a monogalloylglucose isomer (1), a HHDP-glucose isomer (2), Castalin (3) gallic acid (4), vescalagin (5), and grandinin (or its isomer roburin E, 6). X1C and X2C showed a complex composition, including non-phenolic constituents. Fractionation of X2C gave a subfraction, with enhanced alpha-glucosidase inhibitory activity (IC50=6.15mug/mL), with castalagin (7) as the main constituent.

Barium chloride induces redox status unbalance, upregulates cytokine genes expression and confers hepatotoxicity in rats-alleviation by pomegranate peel.[Pubmed:26732703]

Environ Sci Pollut Res Int. 2016 Apr;23(8):7559-71.

The present study was performed to establish the therapeutic efficacy of pomegranate peel against barium chloride induced liver injury. Adult rats were divided into four groups of six animals each: group I, serving as controls, received distilled water; group II received by their drinking water 67 ppm of BaCl2; group III received both 67 ppm of BaCl2 by the same way than group II and 5 % of pomegranate peel (PP) via diet; group IV received 5 % of PP. Analysis by HPLC/MS of PP showed its rich composition in flavonoids such as gallic acid, Castalin, hyperin, quercitrin, syringic acid, and quercetin. The protective effects of pomegranate peel against hepatotoxicity induced by barium chloride were assessed using biochemical parameters and histological studies. Exposure of rats to barium caused oxidative stress in the liver as evidenced by an increase in malondialdehyde (MDA), lipid hydroperoxides (LOOHs), H2O2 and advanced oxidation protein product (AOPP) levels, and lactate dehydrogenase (LDH), gamma glutamyl transpeptidase (GGT), alanine aminotransferase (AST) and aspartate aminotransferase (ALT) activities, a decrease in catalase (CAT) and glutathione peroxidase (GPx) activities, glutathion (GSH), non-protein thiol (NPSH), vitamin C levels, and Mn-SOD gene expression. Liver total MT levels, MT-1, and MT-2 and pro-inflammatory cytokine genes expression like TNF-alpha, IL-1beta and IL-6 were increased. Pomegranate peel, supplemented in the diet of barium-treated rats, showed an improvement of all the parameters indicated above.The present work provided ethnopharmacological relevance of pomegranate peel against the toxic effects of barium, suggesting its beneficial role as a potential antioxidant.

Tannin analysis of chestnut bark samples (Castanea sativa Mill.) by HPLC-DAD-MS.[Pubmed:24679783]

Food Chem. 2014 Aug 15;157:290-5.

In the present investigation, an HPLC-DAD/ESI-MS method for the complete analysis of tannins and other phenolic compounds of different commercial chestnut bark samples was developed. A total of seven compounds (vescalin, Castalin, gallic acid, vescalagin, 1-O-galloyl castalagin, castalagin and ellagic acid) were separated and quantified, being 1-O-galloyl castalagin tentatively identified and found for the first time in chestnut bark samples. Thus, this method provided information regarding the composition and quality of chestnut bark samples, which is required since these samples are commercialised due to their biochemical properties as ingredients of food supplements.

Conformational interpretation of vescalagin and castalagin physicochemical properties.[Pubmed:15053554]

J Agric Food Chem. 2004 Apr 7;52(7):2073-8.

Vescalagin and castalagin are two diastereoisomers. The variability of their principal physicochemical properties, compared with their small structural differences, suggests important conformational variations. This study shows, experimentally, that vescalagin has a greater effect on polarity, oxidizability in solution, and thermodegradability than castalagin. Conformational analysis by molecular mechanics demonstrated that vescalagin was more hydrophilic and was more reactive to electrophilic reagents than castalagin. Experimental results were thus explained and demonstrated the distinct behaviors of vescalagin and castalagin. These results were attributed to the C1 position of the two compounds because vescalin and Castalin have comparable characteristics. Experimental data were confirmed and interpreted by molecular mechanics. This work represents one of the first attempts to correlate conformation and the properties of phenolic compounds. This step constitutes a predictive method for the pharmacology or chemistry of new compounds.

Polyphenols of Melaleuca quinquenervia leaves--pharmacological studies of grandinin.[Pubmed:12916075]

Phytother Res. 2003 Aug;17(7):767-73.

Four polyphenolic acid derivatives and three ellagitannins were isolated from the leaves of Melaleuca quinquenervia (Clav.) S. T. Blake for the first time. Their structures were elucidated as gallic acid (1), ellagic acid (2), 3-O-methylellagic acid (3), 3,4,3'-tri-O-methylellagic acid (4), 2,3-O-hexahydroxydiphenoyl-(alpha/beta)-D-(4)C(1)-glucopyranose (5), Castalin (6) and grandinin (7) on the basis of chemical, mass spectrometric (-ve ESI-MS) and spectroscopic (UV, (1)H-, (13)C NMR, (1)H,(1)H-, (1)H,(13)C-COSY, (1)H,(1)H-TOCSY and HMBC) analyses. Grandinin (the major compound) showed radical scavenging properties by its reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical [EC(50) = 4.3 +/- 0.3 micro g mL(-1)]. It was found to be relatively nontoxic in mice [LD(50) = 316 mg Kg(-1) b.wt.]. It exhibited a significant dose-dependent (35-70 mg Kg(-1)) hypoglycemic effect by significantly reducing blood glucose level in basal condition and after heavy glucose load in normal mice. Moreover, it reduced the elevated blood glucose level in STZ-induced diabetic mice. In addition, grandinin reduced the elevated blood urea nitrogen and serum lipid peroxides in STZ-induced diabetic mice.

The use of tannin from chestnut (Castanea vesca).[Pubmed:1417692]

Basic Life Sci. 1992;59:1013-9.

After mimosa and quebracho extracts, chestnut extract is the third most important vegetable tannin used for leather production. It is produced only in Europe on the northern side of the Mediterranean sea. The extract is prepared by hot water extraction of the bark and timber, followed by spray-drying of the solution. Analysis shows that there are insignificant variations in extract quality between batches, so the extract can be used with modern automated leather production systems. The extract contains approximately 75 percent active tanning substances. The primary component is castalagin, along with smaller amounts of vescalagin, Castalin, and vescalin. A castalagin-based pharmaceutical product is currently in use for prevention and treatment of diarrhea in pigs and cattle that is caused by changes in diet. The beneficial effect is due to prevention of water losses through mucous membranes. The castalagin may also form chelates with iron, which influences the reabsorption of the metal in the animal digestive tract.