79907-47-4Relevant academic research and scientific papers
Systematic synthesis of galloyl-substituted procyanidin B1 and B2, and their ability of DPPH radical scavenging activity and inhibitory activity of DNA polymerases
Saito, Akiko,Mizushina, Yoshiyuki,Ikawa, Hiroshi,Yoshida, Hiromi,Doi, Yuki,Tanaka, Akira,Nakajima, Noriyuki
, p. 2759 - 2771 (2007/10/03)
Six galloyl-substituted procyanidin B1 and B2, 3-O-gallate, 3″-O-gallate, and 3,3″-di-O-gallate, were systematically synthesized with the condensation method using TMSOTf as a catalyst. Their ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity were also investigated. The results indicated that the galloyl group of these compounds is very important for both activities. 3,3″-Di-O-gallate dimers acted as strong inhibitor against DNA polymerase α and β, whereas the desgalloyl and monogalloyl compounds did not exhibit any appreciable inhibitory activity against the DNA polymerase β.
Tannins and Related Compounds. I. Rhubarb (1)
Nonaka, Gen-Ichiro,Nishioka, Itsuo,Nagasawa, Tetsuro,Oura, Hikokichi
, p. 2862 - 2870 (2007/10/02)
Three new tannin-related compounds (I, II and III), along with lindleyin (IV), (+)-catechin, 3-O-galloyl-(-)-epicatechin, gallic acid, 3,5,4'-trihydroxystilbene 4'-O-β-D-(6''-O-galloyl)-glucopyranoside, 3,5,4'-trihydroxystilbene 4'-O-β-D-glucopyranoside and 4-(4'-hydroxyphenyl)-2-butanone 4'-O-β-D-glucopyranoside, have been isolated from commercial rhubarb (Rhei Rhizoma).On the basis of spectral and chemical evidence, I, II and III were characterized as 3,3'-di-O-galloylprocyanidin B-2, 3-O-galloylprocyanidin B-1 and 1,2,6-tri-O-galloylglucose, respectively.The occurence of IV in rhubarb is of great significance, since IV has been reported to have analgesic and anti-inflammatory activities almost equal to those of aspirin and phenylbutanone.Tannins in rhubarb have been partially purified (designated as rhatannin (V)).Thiolysis degradation and enzymatic hydrolysis have shown that V is mainly composed of C4 to C8 linked 3-O-galloyl-(-)-epicatechin units in the extension part (upper part) with either 3-O-galloyl-(-)-epicatechin or (+)-catechin unit in the lower terminal part.Keywords. rhubarb; polygonaceae; 3,3'-di-O-galloylprocyanidin B-2; 3-O-galloylprocyanidin B-1; 1,2,6-tri-O-galloylglucose; lindleyin; rhatannin
