Ochnaflavone Research Articles

Erratum: Ochnaflavone inhibits TNF‐α‐induced human VSMC proliferation via regulation of cell cycle, ERK1/2, and MMP‐9. S.‐J. Suh, U.‐H. Jin, S.‐H. Kim, H.‐W. Chang, J.‐K. Son, S.H. Lee, K.‐H. Son, C.‐H. Kim

AbstractDuring the corresponding author's transfer from Dongguk University to Sungkyunkwan University in March 2006, data from the previous University was transferred to the corresponding author's new computer. During this data transfer there was a mixing of EMSA data from experiments involving Quercetin (QC), Ochnaflavone (OC), Tanshinone (TS), Crytotanshinone (CT), BMK, and natural extracts. The mixed EMSA data was inadvertently incorporated in more than one publication. Figure 6 has been corrected to new data with re‐confirmation. J. Cell. Biochem. 108: 337, 2009. © 2009 Wiley‐Liss, Inc.6. Effect of OC on the TNF‐α‐induced DNA binding activities of MMP‐9, NF‐κB, and AP‐1 motif in HASMC. Cells were pretreated with indicated OC for 40 min in serum‐free medium, were incubated with TNF‐α (100 ng/ml) for 24 h. Nuclear extracts were analyzed by EMSA for the activated NF‐κB (A) and AP‐1 (B) using radiolabeled oligonucleotide probes, respectively. Indicated values are means of three triplicate experiments.image6. Effect of OC on the TNF‐α‐induced DNA binding activities of MMP‐9, NF‐κB, and AP‐1 motif in HASMC. Cells were pretreated with indicated OC for 40 min in serum‐free medium, were incubated with TNF‐α (100 ng/ml) for 24 h. Nuclear extracts were analyzed by EMSA for the activated NF‐κB (A) and AP‐1 (B) using radiolabeled oligonucleotide probes, respectively. Indicated values are means of three triplicate experiments.

The naturally occurring biflavonoid, ochnaflavone, inhibits LPS-induced iNOS expression, which is mediated by ERK1/2 via NF-κB regulation, in RAW264.7 cells

Ochnaflavone (OC), a naturally occurring biflavonoid with anti-inflammatory activity [S.J. Lee, J.H. Choi, H.W. Chang, S.S. Kang, H.P. Kim. Life Sci. 57(6), 1995, 551–558], was isolated from Lonicera japonica and its effects on inducible nitric oxide synthase (iNOS) gene expression was examined in RAW264.7 cells. U0126, an inhibitor of the extracellular signal-regulated kinase (ERK), significantly down-regulated lipopolysaccharide (LPS)-induced iNOS expression and promoter activity. Transactivation of LPS-stimulated NF-κB was inhibited by U0126. These results suggest that the transcription factor NF-κB is involved in ERK-mediated iNOS regulation and that activation of the Ras/ERK pathway contributes to the induction of iNOS expression in RAW264.7 cells in response to LPS. OC treatment inhibited the production of nitric oxide in a concentration-dependent manner and also blocked the LPS-induced expression of iNOS. These inhibitory effects were associated with reduced ERK1/2 activity. OC inhibited the phosphorylation of c-Jun NH 2-terminal kinase (JNK) and p38 mitogen-activated protein kinase. The findings herein show that the inhibition of LPS-induced ERK1/2 activation may be a contributing factor to the main mechanisms by which OC inhibits RAW264.7. To clarify the mechanistic basis for its ability to inhibit iNOS induction, we examined the effect of OC on the transactivation of the iNOS gene by luciferase reporter activity using the −1588 flanking region. OC potently suppressed reporter gene activity. We also report here, for the first time, that LPS-induced iNOS expression was abolished by OC in RAW264.7 cells through by blocking the inhibition of transcription factor NF-κB binding activities. These activities are associated with the down-regulation of inhibitor κB (IκB) kinase (IKK) activity by OC (6 μM), thus inhibiting LPS-induced phosphorylation as well as the degradation of IκBα. These findings suggest that the inhibition of LPS-induced NO formation by OC is due to its inhibition of NF-κB, which may be the mechanistic basis for the anti-inflammatory effects of OC.

A biflavone from ochna pumila

7″- O-Methyl tetrahydroamentoflavone, together with 7″- O-methyl ochnaflavone, ochnaflavone and tetrahydroamentoflavone, has been isolated from the leaves of Ochna pumila. The isolation of tetrahydroamentoflavone and 7″- O-methyl tetrahydroamentoflavone from O. pumila constitutes the first report of their occurrence as a new series of biflavanones.