Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E2 (COX-2) production of flavonoids from seeds of Prunus tomentosa Thunberg

Abstract

Chemical investigation of the 80% Me(2)CO extract from the seeds of Prunus tomentosa led to the isolation and identification of six flavonoids: kaempferol (1), kaempferol 3-O-alpha-L-rhamnopyranoside (2; afzelin), kaempferol 3-O-beta-D-(6-acetyl)-glucopyranosyl(1-->4)-alpha-L-rhamnopyranoside (3; multiflorin A), kaempferol 3-O-beta-D-glucopyranosyl(1-->4)-alpha-L-rhamnopyranoside (4; multiflorin B), quercetin 3-O-alpha-L-rhamnopyranoside (5; quercitrin), and quercetin 3-O-beta-D-glucopyranosyl (1-->4)-alpha-L-rhamnopyranoside (6; multinoside A). Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E(2) production in interferon-gamma (INF-gamma) and lipopolysaccharide (LPS)-activated RAW 264.7 cells in vitro (COX-2) of the isolated compounds were evaluated. Compounds 1, 5, and 6 exhibited potent anti-oxidative activity in the DPPH radical scavenging assay with IC(50) values of 57.2, 59.4, and 54.3 microg/mL respectively. The positive control, ascorbic acid, had an IC(50) of 55.5 mug/mL. Compounds 1, 5, and 6 also reduced COX-2 levels in a dose dependent manner with IC(50) values of 10.2, 8.7, and 9.6 microg/mL respectively, with the positive control, indomethacin, having an IC(50) of 5.1 microg/mL. All six compounds inhibited NO production in a dose dependent manner with IC(50) values of 35.1, 42.8, 40.0, 44.8, 43.7, and 43.9 microg/mL respectively, while the positive control, L-NMMA, had an IC(50) of 42.1 microg/mL.

Afzelin positively regulates melanogenesis through the p38 MAPK pathway

“…Afzelin is a well-known flavonoid with anti-inflammatory, antitumor, and antibacterial activities [1,12,18]. We demonstrated here that afzelin possesses melanogenic activity and that it mediates its effects by activating p38 MAPK.…”

“…The flavonoid afzelin (Kaempferol 3 -O-a-L-rhamnopyranoside) inhibits lipid peroxidation and cyclooxygenase (COX)-1 and COX-2 [12]. The structure of this compound is shown in Fig.…”

Comparative evaluation of the antioxidant effects of the natural vitamin C analog 2-O-β-D-glucopyranosyl-L-ascorbic acid isolated from Goji berry fruit

“…Many studies have demonstrated that AA and other natural compounds are capable of scavenging nitrite (Kim et al, 2008). Dose-dependent AA-2βG and AA nitrite scavenging activity was observed at low pH (pH 3.0) (Fig.…”

“…The AA or AA-2βG nitrite scavenging capacity was determined by colorimetry, as described previously (Kim et al, 2008), and the absorbance was measured at 538 nm. The percentage of nitrite scavenging was calculated using the following equation: NO 2 − scavenging efficiency (%) = (A 0 − A S )/A 0 × 100, where A 0 and A S represent the control or sample (AA or AA-2βG) absorbance, respectively.…”

Glycyrrhiza glabra L. Medicinal Plants as Potential Source of COX-2 Inhibitors

“…Flavonoids are the well studied class of polyphenols as COX-2 inhibitors. Kaempferol and its derivatives isolated from seeds of Prunus tomentosa exhibited inhibitory activities on nitric oxide (NO) and prostaglandin E 2 (COX-2) production [52]. Kaempferol and quercetin exhibited anti-inflammatory activities by inhibiting iNOS and COX-2 protein levels in cultured human umbilical vein endothelial cells [53].…”