Okanin

Korean Journal of Pharmacognosy, 2009 , 40 (4) :345-50.

Antioxidative and hepatoprotective effect of compounds from the flowers of bidens Bipinnata L.[Reference: WebLink]

METHODS AND RESULTS:
Activity-guided fractionation of the EtOH extract of flowers of Bidens bipinnata L. have been furnished five flavonoids, sulfuretin(1), butein(2), 7,8,3′,4′-tetrahydroxyflavanone(3), maritimetin(4) and Okanin(5). All of the compounds showed significant activities on both linoleic acid peroxidation inhibition and DPPH radical scavenging effect. The evaluation for protective effect of isolated compounds against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells was conducted. Compounds 1, 3, 4 and 5 showed significant protective effects with the EC50 values of 36.1±0.9, 23.3±0.7, 41.0±1.0 and 29.8±1.1 μM, respectively.
CONCLUSIONS:
Silybin, one of the well-known hepatoprotective agents, used as a positive control, and also showed protective effect with an EC50 value of 84.3±0.7 μM.

J Clin Biochem Nutr. 2012 Jan; 50(1): 53–58.

Okanin, a chalcone found in the genus Bidens, and 3-penten-2-one inhibit inducible nitric oxide synthase expression via heme oxygenase-1 induction in RAW264.7 macrophages activated with lipopolysaccharide[Pubmed: 22247601]

Okanin is one of the most abundant chalcones found in the genus Bidens (Asteraceae) that is used as various folk medications in Korea and China for treating inflammation.
METHODS AND RESULTS:
Here, we found that Okanin (possessing the α-β unsaturated carbonyl group) induced heme oxygenase-1 expression via nuclear factor-erythroid 2-related factor 2 activation in RAW264.7 macrophages. 3-Penten-2-one, of which structure, as in Okanin, possesses the α-β unsaturated carbonyl group, also induced nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression, while both 2-pentanone (lacking a double bond) and 2-pentene (lacking a carbonyl group) were virtually inactive. In lipopolysaccharide-activated RAW264.7 macrophages, both Okanin and 3-penten-2-one inhibited nitric oxide production and inducible nitric oxide synthase expression via heme oxygenase-1 expression.
CONCLUSIONS:
Collectively, our findings suggest that by virtue of its α-β unsaturated carbonyl functional group, Okanin can inhibit nitric oxide production and inducible nitric oxide synthase expression via nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression in lipopolysaccharide-activated macrophages.

Sci Rep. 2017 Apr 3;7:45705.

Okanin, effective constituent of the flower tea Coreopsis tinctoria, attenuates LPS-induced microglial activation through inhibition of the TLR4/NF-κB signaling pathways.[Pubmed: 28367982 ]

METHODS AND RESULTS:
The EtOAc extract of Coreopsis tinctoria Nutt. significantly inhibited LPS-induced nitric oxide (NO) production, as judged by the Griess reaction, and attenuated the LPS-induced elevation in iNOS, COX-2, IL-1β, IL-6 and TNF-α mRNA levels, as determined by quantitative real-time PCR, when incubated with BV-2 microglial cells. Immunohistochemical results showed that the EtOAc extract significantly decreased the number of Iba-1-positive cells in the hippocampal region of LPS-treated mouse brains. The major effective constituent of the EtOAc extract, Okanin, was further investigated. Okanin significantly suppressed LPS-induced iNOS expression and also inhibited IL-6 and TNF-α production and mRNA expression in LPS-stimulated BV-2 cells. Western blot analysis indicated that Okanin suppressed LPS-induced activation of the NF-κB signaling pathway by inhibiting the phosphorylation of IκBα and decreasing the level of nuclear NF-κB p65 after LPS treatment. Immunofluorescence staining results showed that Okanin inhibited the translocation of the NF-κB p65 subunit from the cytosol to the nucleus. Moreover, Okanin significantly inhibited LPS-induced TLR4 expression in BV-2 cells.
CONCLUSIONS:
In summary, Okanin attenuates LPS-induced activation of microglia. This effect may be associated with its capacity to inhibit the TLR4/NF-κB signaling pathways. These results suggest that Okanin may have potential as a nutritional preventive strategy for neurodegenerative disorders.