Jeong Yeon Seo

Corn silk maysin induces apoptotic cell death in PC-3 prostate cancer cells via mitochondria-dependent pathway

AIMS Despite recent advances in prostate cancer diagnostics and therapeutics, the overall survival rate still remains low. This study was aimed to assess potential anti-cancer activity of maysin, a major flavonoid of corn silk (CS, Zea mays L.), in androgen-independent human prostate cancer cells (PC-3). MAIN METHODS Maysin was isolated from CS of Kwangpyeongok, a Korean hybrid corn, via methanol extraction and preparative C18 reverse phase column chromatography. Maysin cytotoxicity was determined by either monitoring cell viability in various cancer cell lines by MTT assay or morphological changes. Apoptotic cell death was assessed by annexin V-FITC/PI double staining, depolarization of mitochondrial membrane potential (MMP), expression levels of Bcl-2 and pro-caspase-3 and by terminal transferase mediated dUTP-fluorescein nick end labeling (TUNEL) staining. Underlying mechanism in maysin-induced apoptosis of PC-3 cells was explored by evaluating its effects on Akt and ERK pathway. KEY FINDINGS Maysin dose-dependently reduced the PC-3 cell viability, with an 87% reduction at 200 μg/ml. Maysin treatment significantly induced apoptotic cell death, DNA fragmentation, depolarization of MMP, and reduction in Bcl-2 and pro-caspase-3 expression levels. Maysin also significantly attenuated phosphorylation of Akt and ERK. A combined treatment with maysin and other known anti-cancer agents, including 5-FU, etoposide, cisplatin, or camptothecin, synergistically enhanced PC-3 cell death. SIGNIFICANCE These results suggested for the first time that maysin inhibits the PC-3 cancer cell growth via stimulation of mitochondria-dependent apoptotic cell death and may have a strong therapeutic potential for the treatment of either chemo-resistant or androgen-independent human prostate cancer.

Ginseng marc-derived low-molecular weight oligosaccharide inhibits the growth of skin melanoma cells via activation of RAW264.7 cells.

Panax ginseng C.A. Meyer has been traditionally consumed to prevent or treat various medical disorders due to its diverse health benefits. Polysaccharides isolated from Panax ginseng have been known to possess various pharmacological activities, including immune modulating, anti-diabetic, and anti-obesity properties. Despite the increasing number of reports on the bioactivities of ginseng polysaccharides, little is known regarding the medicinal potential of ginseng-derived oligosaccharides. In this study, we prepared a lower-molecular weight oligosaccharide (GOS, MW. 2.2kDa) from ginseng polysaccharides (MW. 11-605kDa) by enzymatic degradation and evaluated for its immunostimulating activities in RAW 264.7 murine macrophage cells. GOS was shown to be a glucan type oligosaccharide mainly containing glucose residues (97.48 in molar %). Treatment with GOS (100-500μg/ml) dose-dependently enhanced the production of TNF-α, IL-6, and NO in RAW 264.7 cells. Western blot analysis indicated that GOS dose-dependently induced the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), p38, and nuclear factor κB (NFκB), which are upstream signalling molecules for cytokine production. While GOS was not cytotoxic to the RAW 264.7 macrophage cells at the concentration tested (up to 1000μg/ml), when B16F10 melanoma cells were co-cultured with the GOS-activated macrophages, the cell viability of melanoma cells was dose-dependently decreased through the induction of apoptotic cell death. Taken together, these results suggested that ginseng marc-derived GOS has anti-cancer activity in vitro against melanoma cells by potentiating macrophage function.

Potential anti-osteoporotic activity of low-molecular weight hyaluronan by attenuation of osteoclast cell differentiation and function in vitro

Due to some severe side effects or lack of efficacy of currently used synthetic drugs, such as bisphosphonates (BPs), the search for new therapeutic agents that can more effectively prevent and treat osteoporosis (OP) has been an increasingly important topic of research. In this study, the low-molecular weight hyaluronan (LMW-HA, 50 kDa) produced by enzymatic degradation of high-molecular weight hyaluronan (HMW-HA, 1922 kDa) from Streptococcus zooepidemicus was evaluated in vitro for its anti-osteoclastogenic potentials using RAW 264.7 murine macrophage cells. LMW-HA (25-200 μg/ml) dose-dependently inhibited the receptor activator of NF-κB ligand (RANKL)-induced tartrate-resistance acid phosphatase (TRAP) activity and the formation of multinucleated osteoclasts. Western blot analysis showed that LMW-HA reduced the RANKL-induced expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), gelsolin and c-Src-proline-rich tyrosine kinase 2 suggesting that it could inhibit actin ring formation of osteoclast cells. In addition, LMW-HA inhibited the bone resorption activity of osteoclastic cells by dose-dependently attenuating the RANKL-induced expression of carbonic anhydrase II and integrin β3. RT-PCR analysis showed that LMW-HA dose-dependently decreased the expression of osteoclast-specific genes, such as matrix metalloproteinase 9 (MMP-9) and cathepsin K, suggesting that it has potential to inhibit the differentiation of osteoclastic cells. Taken collectively, these results suggested that LMW-HA (50 kDa) has significant anti-osteoporotic activity in vitro and may be used as a potent functional ingredient in health beneficial foods or as a therapeutic agent to prevent or treat OP.

Neuroprotective effects of the Phellinus linteus ethyl acetate extract against H2O2-induced apoptotic cell death of SK-N-MC cells

Numerous studies have suggested that neuronal cells are protected against oxidative stress-induced cell damage by antioxidants, such as polyphenolic compounds. Phellinus linteus (PL) has traditionally been used to treat various symptoms in East Asian countries. In the present study, we prepared an ethyl acetate extract from the fruiting bodies of PL (PLEA) using hot water extraction, ethanol precipitation, and ethyl acetate extraction. The PLEA contained polyphenols as its major chemical component, and thus, we predicted that it may exhibit antioxidant and neuroprotective effects against oxidative stress. The results showed that the pretreatment of human brain neuroblastoma SK-N-MC cells with the PLEA (0.1-5 μg/mL) significantly and dose-dependently reduced the cytotoxicity of H2O2 and the intracellular ROS levels and enhanced the expression of HO-1 (heme oxygenase-1) and antioxidant enzymes, such as CAT (catalase), GPx-1 (glutathione peroxidase-1), and SOD-1 and -2 (superoxide dismutase-1 and -2). The PLEA also directly scavenged free radicals. PLEA pretreatment also significantly attenuated DNA fragmentation and suppressed the mRNA expression and activation of mitogen-activated protein kinases extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 kinase, which are induced by oxidative stress and lead to cell death. PLEA pretreatment inhibited the activation of the apoptosis-related proteins caspase-3 and poly (ADP-ribose) polymerase. These results demonstrate that the PLEA has neuroprotective effects against oxidative stress (H2O2)-induced neuronal cell death via its antioxidant and anti-apoptotic properties. PLEA should be investigated in an in vivo model on its potential to prevent or ameliorate neurodegenerative disease.

Corn silk maysin ameliorates obesity in vitro and in vivo via suppression of lipogenesis, differentiation, and function of adipocytes

Present study was aimed to investigate the potential anti-obesity effects of maysin, a major flavonoid of corn silk, in vitro and in vivo using 3T3-L1 preadipocyte cells and C57BL/6 mice. Maysin decreased the levels of intracellular lipid droplets and triglycerides (TG), and down-regulated the protein expression levels of C/EBP-β, C/EBP-α, PPAR-γ, and aP2 in 3T3-L1 preadipocyte cells, suggesting that maysin inhibits lipid accumulation and adipocyte differentiation. In addition, maysin was shown to induce the apoptotic cell death in 3T3-L1 preadipocyte cells via activation of caspase cascades and mitochondrial dysfunction, which may ultimately lead to reduction of adipose tissue mass. Furthermore, oral administration of maysin (25mg/kg body weight) decreased weight gain and epididymal fat weight in high-fat diet (HFD)-fed C57BL/6 mice. Administration of maysin also reduced serum levels of TG, total-cholesterol, LDL-cholesterol, and glucose. Taken collectively, these results suggest for the first time that the purified maysin exerts an anti-obesity effect in vitro and in vivo. These observations may support the applicability of maysin as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat obesity.

3-O-Glucosylation of quercetin enhances inhibitory effects on the adipocyte differentiation and lipogenesis

Glycosylation of natural flavonoids with various sugar moieties can affect their physicochemical and pharmacological properties. In this study, the plant flavonoids quercetin aglycon (Quer) and quercetin 3-O-glucoside (Q3G) were evaluated and compared for their potential anti-obesity effects. The Q3G dose-dependently reduced the TG contents and lipid accumulation in 3T3-L1 adipocyte cells, by 52% and 60% at 20μM, respectively, compared to differentiated control (100%), which were 1.6-fold and 2.4-fold higher reduction than Quer. The Q3G (20μM) also more significantly reduced the expression of adipogenic markers such as C/EBP-β, C/EBP-α, PPAR-γ, and aP2 than Quer, indicating that the Q3G suppresses both adipocyte differentiation and lipogenesis more effectively than Quer in vitro. Comparing to those in the high-fat diet (HFD) fed mice control group for 10 weeks, both the body and liver weights and the size of adipocytes in epididymal adipose tissues were significantly reduced in HFD mice fed with Q3G for another 6 weeks (30mg/kg body weight by oral administration), accompanied by the reductions of TG, total cholesterol, and HDL-cholesterol in serum. The Q3G also reduced the levels of the lipid metabolism-associated proteins, PPAR-γ, SREBP-1c, and FAS in the liver tissues. These results clearly demonstrated that Q3G exhibits a stronger anti-obesity effect than Quer and its anti-obesity effect is mediated via inhibition of adipocyte differentiation and lipogenesis, decreasing serum lipid levels by altering hepatic lipid metabolism, and reducing body weight gain. The results of this study suggest that the Q3G, but not Quer, can be a potent functional ingredient of beneficial health foods or a therapeutic agent to prevent or treat obesity.

Quercetin 3-O-xyloside ameliorates acute pancreatitis in vitro via the reduction of ER stress and enhancement of apoptosis

BACKGROUND AND PURPOSE Glycosylation of phenolic compounds has been reported to increase water-solubility, reduce toxicity, and sometimes give improved or novel pharmacological activities. Present study was aimed to evaluate and compare the beneficial effects of quercetin aglycone (Quer) and its glycosylated derivative, quercetin 3-O-xyloside (Quer-Xyl), against acute pancreatitis (AP). METHODS The cellular acute pancreatitis model was established by treating the rat pancreatic acinar cells (AR42J) with lipopolysaccharide (10 µg/ml) and cerulein (10-7 M). The cytotoxicity of Quer or Quer-Xyl on AR42J cells was assessed by MTT assay. Calcium and ROS levels were fluorometrically determined. The ER stress levels (PERK, GRP78), expression levels of amylase and lipase, and apoptotic markers (caspase-3 and -9) were measured by RT-PCR, western blotting, or fluorometric assay. RESULTS While Quer increased the mRNA expressions of AP marker enzymes, amylase and lipase, Quer-Xyl dose-dependently reversed their expressions. Quer-Xyl suppressed intracellular ROS production and both mRNA and protein levels of GRP78 and PERK, which were significantly elevated in cerulein and LPS-treated AR42J cells. Further, RT-PCR and fluorescence assay revealed that Quer-Xyl dose-dependently augmented the mRNA expressions and activities of caspase-3 and -9. CONCLUSION These results showed that Quer-Xyl, but not Quer, has a significant anti-pancreatitis activity through attenuating intracellular ROS production and ER stress response and enhancing apoptotic cell death, suggesting that it might be useful as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat AP.

Effects of Molecular Weights of Sodium Hyaluronate on the Collagen Synthesis, Anti-inflammation and Transdermal Absorption

In this study, we examined the effects of various molecular weights (1, 10, 50, 100, 660, and 1500 kDa) of sodium hyaluronate (HA), which were prepared by enzyme hydrolysis, on the collagen synthesis, anti-inflammation and skin absorption. These HA did not significantly affect the viability of human dermal fibroblast Hs68 cells. Among them, 1500 kDa, 50 kDa HA most significantly increased collagen production by 59%, and 50% in the Hs 68 cells, respectively. Whereas 1500 and 660 kDa HA hardly pass through mouse transdermis membrane, lower molecular weights (1, 10, or 50 kDa) of HA showed time-dependent increase in skin permeation. HA of 50 kDa showed highest anti-inflammatory effects by reducing nitric oxide and tumor necrosis factor-α production in the RAW 264.7 cells, comparing to other HA (1, 10, and 100 kDa HA). Recently, there is no report about anti-wrinkle and anti-inflammatory effects and skin permeation of different molecular weights HA (1, 10 , 50, 100, 660 and 1500 kDa), which were produced by enzyme hydrolysis. These results suggested that 50 kDa HA can be potent candidates for the development of effective anti-aging and anti-wrinkle cosmetic agents. The results of this study demonstrated that among those HA with different molecular weights, 50 kDa HA showed highest anti-inflammatory activity, significant capability to induce collagen synthesis and high level of skin permeation.