Catechin Glucosides: Occurrence, Synthesis, and Stability

Abstract

Catechins are flavonoids with suggested health benefits, but are unstable during storage, processing and, after ingestion, during gut transit. We hypothesized that catechin glucosides, which occur in various plants, could be more stable than unsubstituted catechin, and additionally be deglucosylated in the gut and so act to deliver catechin in a form able to be absorbed. (+)-Catechin O-glucosides from various sources have been used in the course of this investigation. (+)-Catechin 3'-O-beta-D-glucopyranoside (C3'G), (+)-catechin 5-O-beta-D-glucopyranoside (C5G), and (+)-catechin 3-O-beta-D-glucopyranoside (C3G) were chemically synthesized. (+)-Catechin 4'-O-beta-D-glucopyranoside (C4'G) and (+)-catechin 7-O-beta-D-glucopyranoside (C7G) were prepared enzymically using preparations from lentil and barley. In general, but with some exceptions, the (+)-catechin glucosides were more stable between pH 4 and 8 than (+)-catechin, with C3'G exhibiting greatest stability. The intestinal metabolism of (+)-catechin and all (+)-catechin glucosides in the gut was determined by perfusion of rat intestine in vivo. C3'G and C5G were extensively deglycosylated in the gut, and C3'G showed greatest apparent "absorption" as calculated by the difference between effluent and influent. The results show the potential of catechin glucosides, especially C3'G, as more stable prescursors of catechin.

Terpenoids of Boswellia neglecta oleo-gum resin

“…Previous phytochemical studies on the plant resin resulted in the identification of monoterpenes with α-thujene, α-pinene and terpin-4-ol as major constituents [7], diterpenes [8], triterpenes [9][10][11]. In this communication, phytochemical analysis of the steam distilled residue of the plant oleo-gum resin resulted in the isolation of one new ursane-type triterpenes characterized as 3α-acetoxy-28-hydroxy-11-oxours-12-en-24-oic acid (1) together with known compounds 3α,11α-dihydroxyurs-12-en-24-oic acid (2), 11-oxo-β-boswellic acid (3), α-Boswellic acid (4), β-boswellic (5), ursolic acid (6), lupeol (7) [8], β-amyrin (8) and α-amyrin (9), α-amyrone (10) [9], quercetin (11) [12], olean-12-en-3-O-β-glucoside (12) [13] and catechin-3-O-glucoside (13) [14]. Compounds 1, 2, 11, 12 and 13 are reported from B. neglecta gum resin for the first time.…”

“…Compounds 1, 2, 11, 12 and 13 are reported from B. neglecta gum resin for the first time. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] showed no spot and solvent recovered. Sub-fraction II (fractions 30-60) produced colorless oil and was kept under freezing conditions a waiting GC-MS analysis.…”

Flavonoid Metabolites in the Hemolymph of European Pine Sawfly (Neodiprion sertifer) Larvae

“…1D-TOCSY detected glucosyl subspectra of compounds B and C were further analyzed with the aid of PERCH NMR software (Laatikainen et al, 1996). Finally, the measured NMR data (chemical shifts and coupling constants) was compared with literature data (Fossen et al, 1997;Fossen and Andersen, 2006;Raab et al, 2010). Further information about NMR measurements and the 1 H and 13 C NMR spectral data of the compounds A-D is presented in the Supplemental Information and Supplemental Table 1.…”

Optimization of Glycosyl Aesculin Synthesis by Thermotoga neapolitana β-Glucosidase Using Response-surface Methodology

“…Addition of a sugar moiety to the biologically active compounds by glycosylation can improve their biological activities as well as the low water solubility and low absorption rate in small intestine [6,7,9,20]. The β-glucosidase from hyperthermophilic bacterium Thermotoga neapolitana has been successfully used to attach the sugar moiety to the various biologically active compounds and the resultant glycosylated compounds enhanced solubility and biological half-life [4,8,16].…”