Jung Hee Cho

Neuroprotective effect of Citrus unshiu immature peel and nobiletin inhibiting hydrogen peroxide-induced oxidative stress in HT22 murine hippocampal neuronal cells

Background: Oxidative stress-induced cell damage is common in the etiology of several neurobiological disorders, including Alzheimers disease and Parkinsons disease. In a case study, nobiletin-rich Citrus reticulata peels could prevent the progression of cognitive impairment in donepezil-preadministered Alzheimers disease patients. Objective: In this study, we investigated the effects and underlying mechanism of nobiletin and Citrus unshiu immature peel (CUIP) water extract, which contains nobiletin as a major compound, on hydrogen peroxide-induced oxidative stress in HT22 cells, a murine hippocampal neuronal model. Materials and Methods: HT22 cells were treated with hydrogen peroxide in the presence or absence of various concentrations of CUIP and nobiletin. Cytotoxicity and apoptotic protein levels were measured by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and Western blotting. Results: Pretreatment with CUIP and nobiletin inhibited cell death due to hydrogen peroxide. Hydrogen peroxide-induced the expression of phospho-Jun N-terminal kinases (p-JNK) and p-p38 proteins in HT22 cells; however CUIP and nobiletin suppressed p-JNK and p-p38 without changing JNK or p38. Regarding apoptosis, caspase 3, B-cell lymphoma 2 (Bcl-2), and Bax protein expression was determined. CUIP and nobiletin suppressed caspase 3 and Bax expression, but they induced Bcl-2 expression in HT22 cells. Conclusion: These results show that CUIP and nobiletin can protect against hydrogen peroxide-induced cell death in HT22 neurons via mitogen-activated protein kinases and apoptotic pathways.

Inhibitory Effect of Alopecurus aequalis Sobol Ethanol Extracts on LPS-induced Inflammatory Response in RAW 264.7 Cells

In the present study, we investigated the anti-inflammatory effects by Alopecurus aequalis Sobol on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production by RAW 264.7 cell line. Consistent with these observations, DS reduced the LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein levels in a concentration-dependent manner. In addition, the release of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were also reduced by DS. Moreover, LPS increased expression phosphorylation of IκBα, but DS showed inhibitory effect by reducing LPS-inducible p-IκBα expression level. These results suggest that the down regulation of iNOS, COX-2, TNF-α, and IL-6 expression by DS are achieved by the downregulation of NF-κB activity, a transcription factor necessary for pro-inflammatory mediators, and that is also responsible for its anti-inflammatory effects.

Whitening and Anti-wrinkle Effects of Korean Native Dendrobium moniliforme Methanol Extract

*Jeollanamdo Development Institute of Korean Traditional Medicine, Jangheung 529-851, Korea.**Research Institute, Gyeongsangnam-do Agricultural Research & Extension Services, Changwon 641-920, Korea.***Namhae Sub-Station, NIHHS, RDA, Namhae 668-812, Korea. ABSTRACT : Dendrobium moniliforme (DM) is a valuable and versatile herbal medicine with the anecdotal claims of anti-oxidant and anti-inflammation. In the present study, we investigated the whitening and anti-wrinkling effects of DM undervarious conditions with B16F10 melanoma cells and human dermal fibroblasts. The DM extract inhibited melanin contentsand tyrosinase activity in a dose-dependent manner, compared with untreated group. Treatment of the DM extract effec-tively suppressed the α-MSH-stimulated melanin formation, tyrosinase activity and dendrite outgrowth. Moreover, the α-MSH-induced mRNA expressions of tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2) andprotein expression of tyrosinase were significantly attenuated by DM treatment. We also investigated the DM increased theproduction of type I procollagen and inhibited TNF- α-induced mRNA expressions of MMP-1, -3 in the human dermal fibro-blast. These results indicate that DM may be a great cosmeceutical ingredient for its whitening and anti-wrinkle effects.Key Words : Whitening, Anti-wrinkling, Dendrobium moniliforme, Melanin, Tyrosinase

Effect of Dendrobium loddigesii Rolfe Methanol Extract on Melanogenesis in α-MSH Stimulated B16F10 Cells

*Jeollanamdo Development Institute of Traditional Korean Medicine, Jangheunggun 529-851, Korea.**Research Institute, Gyeongsangnamdo Agricultural Research and Extension Services, Changwon 641-920, Korea.***Namhae Sub-Station, National Institute of Horticultural and Herbal Science, RDA, Namhae 668-812, Korea.ABSTRACT : Dendrobium loddigesii (DL) is a valuable and versatile herbal medicine with the anecdotal claims of anti-oxi-dant and anti-inflammation. In the present study, we investigated the whitening effects of DL under various conditions withB16F10 melanoma cells. The DL extract inhibited melanin contents and tyrosinase activity in a dose-dependent manner,compared with untreated group. Treatment of the DL extract effectively suppressed the α-MSH-stimulated melanin forma-tion, tyrosinase activity and dendrite outgrowth. Moreover, the α-MSH-induced mRNA expressions of tyrosinase-relatedprotein-1 (TRP-1), tyrosinase-related protein-2 (TRP-2), microphthalmia-associated transcription factor (MITF) and pro-tein expression of tyrosinase were significantly attenuated by DL treatment. These results indicate that DL may be a greatcosmeceutical ingredient for its whitening effects.Key Words : Dendrobium loddigesii, Whitening, Melanin, Tyrosinase

Effect of Dendrobium speciosum Var. Aqueous Extract on Loperamide-Induced Constipation in Rats

Background : Irregular meals and insufficient exercise are major modern lifestyle-related risk factors for constipation. This study aimed to examine the effects of the aqueous extract of Dendrobium speciosum var. (DM) on the improvement of intestinal function and prevention of constipation in rats. Methods and Results : Constipation in rat was induced by loperamide (4 mg/kg) injection for 5 days and rats were randomly assigned to the following groups: normal control rats (NOR), constipated rats (LOP induced) and constipated rats supplemented with dulcolax-S (POS), DMSG, 100 mg/kg (DMSG-100), 300 mg/kg (DMSG-300) and 500 mg/kg (DMSG-500). The DMSG groups showed increments in the frequency and amount of stools compared to the LOP group. Loperamide treatment markedly reduced the water content of feces, whereas DMSG administration significantly increased fecal water contents. Moreover, DMSG improved intestinal transit speed in constipated-rats. Alcian blue staining revealed increased mucus production by crypt cells and mucus contents in feces and the mucosal surface. Conclusions : In summary, DM extraction significantly improves intestinal function in rats, which indicates the effectiveness of this extract in the prevention and treatment of constipation.