Dong Ki Park

Antioxidative activity of persimmon and grape seed extract: in vitro and in vivo

Abstract We determined in vitro radical scavenging activity of persimmon seed extract (PSE) and grape seed extract (GSE), and quantified total tannin concentrations of each extract. It has been found that both PSE and GSE have radical scavenging activities, and total tannin concentration of PSE was significantly higher than GSE ( p p in vitro, and inhibited lipid peroxidation in vivo .

Antioxidative effect of chitosan on chronic carbon tetrachloride induced hepatic injury in rats

Carbon tetrachloride (CCl(4)) is a toxic material known to induce lipid peroxidation and liver damage. To determine if chitosan has antioxidative effects on CCl(4)-induced liver injury, we administered 1 ml/kg of CCl(4) resolved in a 50% corn oil solution to rats every week by intraperitoneal injection. Chitosan (200 mg/kg body weight per day, MW 380,000 Da) was administered to the CCl(4) + chitosan treated rats by oral gavage during the experimental period. Chitosan significantly decreased liver thiobarbituric acid reactive substances (TBARS) and increased antioxidant enzyme activities (catalase and superoxide dismutase (SOD)). Fatty acid composition was not remarkably changed by chitosan; only arachidonic acid (20:4n-6) levels were significantly altered by CCl(4). Chitosan administration in the present experiment did not restore the decreased delta5-desaturase activity. In addition, chitosan supplementation did not prevent the CCl(4) induced degradation of CYP2E1. In conclusion, our results suggest that chitosan has antioxidative but not detoxifying effects on chronic CCl(4) induced hepatic injury in rats.

Topical application of Polygonum multiflorum extract induces hair growth of resting hair follicles through upregulating Shh and β-catenin expression in C57BL/6 mice

ETHNOPHARMACOLOGICAL RELEVANCE Polygonum multiflorum has traditionally been used for treating patients suffering from baldness and hair loss in East Asia. AIM OF THE STUDY The present study sought to investigate the hair growth promoting activities of Polygonum multiflorum and its mechanism of action. MATERIALS AND METHODS The Polygonum multiflorum extract was topically applied to the shaved dorsal skin of telogenic C57BL6/N mice. To determine the effect of Polygonum multiflorum extract in telogen to anagen transition, the expression of β-catenin and Sonic hedgehog (Shh) was determined by immunohistochemistry analysis. RESULTS Polygonum multiflorum extract promoted hair growth by inducing anagen phase in telogenic C57BL6/N mice. In Polygonum multiflorum extract treated group, we observed increase in the number and the size of hair follicles that are considered as evidence for anagen phase induction. Immunohistochemical analysis revealed that earlier induction of β-catenin and Shh were observed in Polygonum multiflorum extract treated group compared to that in control group. CONCLUSION These results suggest that Polygonum multiflorum extract promotes hair growth by inducing anagen phase in resting hair follicles.

Application of flow injection--chemiluminescence to the study of radical scavenging activity in plants.

Chemiluminescence (CL) was observed during the oxidation of luminol (2 mg/L). mediated by 0.06% hydrogen peroxide (H2O2) and cytochrome c (10 mg/L). CL intensity was decreased by the presence of radical scavengers and the reduction was linearly proportional to the concentration and ability of scavengers; butylated hydroxytoluene (BHT), caffeic acid and gallic acid. The order of effectiveness as radical scavengers was gallic acid > caffeic acid > BHT, which shows that the number of hydroxyl groups (OH) in the B‐ring of flavonoids plays a key role in a good radical scavenging activity. Of eight catechins obtained from green tea extracts, (−)‐catechin was the least effective and (−)‐epigallocatechin gallate (EGCg) showed the strongest activity. This result indicates that the stereoscopic structure between the C‐3 group and the B ring of flavonoids as well as substituents at the C‐3 position make a contribution to radical scavenging activity. Of the tested Chinese herbal ingredients, five species of ingredients represented more than 90% of the radical scavenging activity.

Effect of dietary restriction on age-related increase of liver susceptibility to peroxidation in rats

Dietary restriction (DR) increases life span and decreases age-related diseases in experimental animals. It has received a great deal of attention in connection with the relationship between aging, nutrition, and oxidative stress because oxidative injury in several organ systems is a prominent feature in aging. We investigated the possibility that DR can protect vulnerable liver lipids against age-related increases of peroxidation. Male Fischer 344 rats fed ad libitum (AL) or dietarily restricted (maintained on 60% of AL food intake) were killed by decapitation at 4 (young) or 12 mon (adult) of age. Phosphatidylcholine hydroperoxide (PCOOH) concentration of liver was determined using a chemiluminescent high-performance liquid chromatographic method. Liver PCOOH increased with age in adult rats, but less of an increase of PCOOH was seen in DR rats, which is consistent with results on production of thiobarbituric acid-reactive substances and oxygen-derived free radicals. No significant differences were found in liver superoxide dismutase and catalase activity between AL and DR groups of young and adult rats. Liver triglyceride and cholesterol contents were lower in DR than AL rats at 12 mon. Fatty acid compositions of phosphatidylcholine and phosphatidylethanolamine indicated that the ratio of (20∶3n−6+20∶4n−6)/18∶2n−6, an index of linoleic acid (18∶2n−6) desaturation, was lower in DR than in AL rats. We concluded that DR suppresses age-related oxidative damage in liver by modulating the amount of lipid as well as fatty acid composition.

Extracts of Phellinus linteus grown on germinated brown rice suppress liver damage induced by carbon tetrachloride in rats.

Extracts of Phellinus linteus (EPB), grown on germinated brown rice, protected rats from liver injury induced by carbon tetrachloride (CCl4). Peroxidation products in the liver were decreased to 10% by EPB. Catalase and superoxide dismutase activities were significantly decreased to 55% and 39% by CCl4 administration, but EPB blocked this effect, resulting in enzyme activities at control levels. Expression of cytochrome P450 2E1 (CYP2E1) protein was significantly decreased to 88% in CCl4-treated rats but remained at control levels when EPB was also administered. EPB did not affect the altered fatty acid composition induced by CCl4. The hepatoprotective effect of EPB may be mediated by EPBs prevention of CCl4-induced CYP2E1 degradation.

Comparative study on the modulation of IgE and cytokine production by Phellinus linteus grown on germinated brown Rice, Phellinus Linteus and germinated brown rice in murine splenocytes.

We compared the immunomodulating activities in mice of extracts from Phellinus linteus grown on germinated brown rice (PB), Phellinus linteus (PL) alone, and germinated brown rice (BR) alone. The PL, BR and PB-treated mice were administered with the respective extract (2 mg/head/day) by oral gavage for 4 weeks. All extracts markedly decreased the IgE production and allergic responses in serum and splenocytes. PL and PB increased the proportion of CD4+ but not CD8+ T cells in splenocytes. Cytokine production was significantly augmented in all treated mice; the concentration of IFN-γ was greater in the PL, BR and PB mice than in the control group. The concentration of IL-10 was lower in the BR group than in the other groups. These results may be related to the suppression of IgE production. We conclude that PB modulated the immune responses of IgE production and Th1/Th2 cytokine secretion in murine splenocytes.

The ethyl acetate extract of PGP (Phellinus linteus grown on Panax ginseng) suppresses B16F10 melanoma cell proliferation through inducing cellular differentiation and apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE Phellinus linteus and Panax ginseng have been widely used as traditional herbal medicines to treat various diseases including cancer in East Asia. AIM OF THE STUDY The present study sought to investigate the possible mechanism in anti-proliferative effect of Phellinus linteus that was grown on Panax ginseng (PGP) on B16F10 melanoma cells. MATERIALS AND METHODS The anti-proliferative effect of PGP on B16F10 was evaluated by CCK-8 assays. Apoptotic cells were detected by flow cytometry analysis. The proteins involved in apoptosis and cellular differentiation were assessed by immunoblot analysis. Ginsenosides contents of PG or PGP were analyzed using HPLC. RESULTS The ethyl acetate fraction (EtOAc) of PGP exhibited the strongest anti-proliferative activity among PGP fractions (butanol or water) on B16F10 cells. PGP EtOAc extract showed stronger inhibitory effect than Panax ginseng (PG) or Phellinus linteus (PL) EtOAc extract on B16F10 melanoma cell proliferation. PGP EtOAc extract induced the dendrite-like structures and the melanin production in B16F10 cells. PGP EtOAc extract increased a sub-G1 cell population through inducing p53/p21 and activated caspase-8 protein expression in B16F10 cells. Notably, PGP EtOAc extract contained ginsenosides Rd, Rg3, Rb2, Rg1 and Rb1 more than PG EtOAc extract. Rd and Rg3 significantly inhibited B16F10 cell proliferation. CONCLUSION Our data suggest that PGP EtOAc extract inhibits B16F10 cell proliferation through inducing apoptosis and cellular differentiation.

The Src Family Kinase Fgr Is Critical for Activation of Mast Cells and IgE-Mediated Anaphylaxis in Mice

Mast cells are critical for various allergic disorders. Mast cells express Src family kinases, which relay positive and negative regulatory signals by Ag. Lyn, for example, initiates activating signaling events, but it also induces inhibitory signals. Fyn and Hck are reported to be positive regulators, but little is known about the roles of other Src kinases, including Fgr, in mast cells. In this study, we define the role of Fgr. Endogenous Fgr associates with FcεRI and promotes phosphorylation of Syk, Syk substrates, which include linkers for activation of T cells, SLP76, and Gab2, and downstream targets such as Akt and the MAPKs in Ag-stimulated mast cells. As a consequence, Fgr positively regulates degranulation, production of eicosanoids, and cytokines. Fgr and Fyn appeared to act in concert, as phosphorylation of Syk and degranulation are enhanced by overexpression of Fgr and further augmented by overexpression of Fyn but are suppressed by overexpression of Lyn. Moreover, knockdown of Fgr by small interfering RNAs (siRNAs) further suppressed degranulation in Fyn-deficient bone marrow-derived mast cells. Overexpression of Fyn or Fgr restored phosphorylation of Syk and partially restored degranulation in Fyn-deficient cells. Additionally, knockdown of Fgr by siRNAs inhibited association of Syk with FcεRIγ as well as the tyrosine phosphorylation of FcεRIγ. Of note, the injection of Fgr siRNAs diminished the protein level of Fgr in mice and simultaneously inhibited IgE-mediated anaphylaxis. In conclusion, Fgr positively regulates mast cell through activation of Syk. These findings help clarify the interplay among Src family kinases and identify Fgr as a potential therapeutic target for allergic diseases.

Morus bombycis Koidzumi extract suppresses collagen-induced arthritis by inhibiting the activation of nuclear factor-κB and activator protein-1 in mice.

ETHNOPHARMACOLOGICAL RELEVANCE Morus bombycis Koidzumi is widely distributed in Asia. In Korea, it has been used in traditional medicine because of its apparent anti-inflammatory, antioxidant, and hepatoprotective properties. AIM OF THE STUDY Although the extract of Morus bombycis Koidzumi (MB) has long since been used as a traditional anti-inflammatory medicine in Korea, its effect on arthritis remains unknown. We aimed to investigate the anti-arthritis activity of MB and the mechanism underlying it. MATERIALS AND METHODS The anti-arthritis activity of MB was assessed by using mouse models of type II collagen-induced arthritis (CIA). The clinical arthritis index and histopathological changes were evaluated in mice. Reverse transcriptase-polymerase chain reaction (RT-PCR), electrophoretic mobility shift assay (EMSA), and other biologic approaches were used for measuring the effect of MB on arthritis and understanding the underlying mechanism. RESULTS MB significantly decreased the clinical arthritis index in CIA mice; this was confirmed by examining histological changes in joints. Infiltration of immune cells, synovial hyperplasia, cartilage destruction, and bone erosion in the hind paw were largely suppressed by MB. The mRNA levels of matrix metalloproteinase (MMP)-1/MMP-3, inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6), and chemokines (macrophage inflammatory protein (MIP)-1, monocyte chemoattractant protein (MCP)-1, RANTES) were significantly suppressed by MB in a dose-dependent manner. The number of osteoclasts in the hind tibia was also significantly decreased. With regard to the mechanism, MB suppressed the activation of nuclear factor (NF)-κB and activator protein (AP)-1 in CIA mice. CONCLUSIONS MB produced an anti-arthritis effect in CIA mice by inhibiting the production of critical inflammatory mediators and osteoclasts through the downregulation of NF-κB and AP-1.