Flavan-3-ols Isolated from Some Medicinal Plants Inhibiting COX-1 and COX-2 Catalysed Prostaglandin Biosynthesis

Abstract

Extracts from the four plant species Atuna racemosa Raf. ssp. racemosa, Syzygium corynocarpum (A. Gray) C. Muell., Syzygium malaccense (L.) Merr. & Perry and Vantanea peruviana Macbr., traditionally used for inflammatory conditions, were fractionated using a cyclooxygenase-1 catalysed prostaglandin biosynthesis in vitro assay. The flavan-3-ol derivatives (+)-catechin, (+)-gallocatechin, 4'-O-Me-ent-gallocatechin, ouratea-catechin and ouratea-proanthocynidin A were isolated as active principles. The IC50 values ranged from 3.3 microM to 138 microM whilst indomethacin under the same test conditions had an IC50 value of 1.1 microM. The flavonol rhamnosides mearnsitrin, myricitrin and quercitrin were also isolated. When further tested for inhibitory effect on cyclooxygenase-2 catalysed prostaglandin biosynthesis, the five flavan-3-ol derivatives exhibited from equal to weaker inhibitory potencies, as compared to their cyclooxygenase-1 inhibitory effects. The flavonol rhamnosides were inactive towards both enzymes.

Estudo fitoquímico e avaliação das atividades moluscicida e larvicida dos extratos da casca do caule e folha de Eugenia malaccensis L. (Myrtaceae)

“…& Perry), conhecida popularmente no Brasil como jambo vermelho, jambo roxo e jambo encarnado, faz parte das plantas medicinais do Estado de Alagoas, sendo as folhas e os frutos usados como adstringentes e estimulantes do apetite, como diuréticos e no combate a anemias, principalmente pelas populações de baixo poder aquisitivo (Campelo, 1988). Em várias partes do mundo, E. malaccense, é empregada, na medicina popular, no tratamento de processos infl amatórios, febre, coceira, diabetes, catarro no pulmão, tosse, dores de cabeça, disenteria e como diurético (Dunstan et al 1997;Noreen et al 1998). Estudos farmacológicos demonstraram a atividade antiviral seletiva do extrato aquoso da casca do caule frente aos vírus da Herpes Simplex-1 (HSV-1) e 2 (HSV-2), da estomatite vesicular e HIV-1 (Locher et al, 1995;1996), enquanto, o extrato aquoso das folhas revelou forte inibição das bactérias Staphylococcus aureus e do Streptococcus pyogenes (Locher et al, 1995) tendo sido isolado o ácido elágico, o 3-O-metilelágico e o 3,3'-O-dimetilelágico.…”

“…Estudos químicos efetuados com as folhas de E. malaccensis levaram ao isolamento de quatro fl avonóides: catequina, mearnsitrina, miricitrina e quercitrina (Noreen et al, 1998); dos frutos foram obtidos compostos voláteis (Pino et al, 2004). A partir das fl ores foi isolada a antocianina, 3,5-diglicosílmalvidina (Lowry, 1976a), enquanto do caule foram isolados os ácidos elágico, 3-Ometilelágico e 3,3'-O-dimetilelágico (Lowry, 1968).…”

MtPAR MYB transcription factor acts as an on switch for proanthocyanidin biosynthesis in Medicago truncatula

“…PAs and their monomeric building blocks catechin and epicatechin are antioxidants with beneficial effects on human health, including cardioprotective (2), anticancer (3), and anti-inflammatory activities (4). PAs in forage plants bind to proteins and slow their fermentation in the rumen, reducing microbial production of methane and thereby protecting the animal from potentially lethal pasture bloat (1).…”

Anti-inflammatory activity and modulate oxidative stress of Bucida buceras in lipopolysaccharide-stimulated RAW 264.7 macrophages and Carrageenan-induced acute paw edema in rats

“…We found that Bucida extract contains gallic acid, catechins, aesculetin, rutin and quercetin. The anti-inflammatory effect may be due to synergistic effect rather than a single constituent Groups Welton et al (1986) demonstrated that quercetin and kaempferol inhibited cyclooxygenase-2 in rat peritoneal macrophages while catechin weakly inhibits cyclooxygenase-2 but a very high concentration (100 μM) (Noreen et al, 1998). Flavonols such as kaemperol, quercetin, morin and myricetin were found to better lipoxygenase inhibitors than flavones.…”