Effects of Harvest Time on Phytochemical Constituents and Biological Activities of Panax ginseng Berry Extracts.

Ginseng (Panax ginseng) has long been used as a traditional medicine for the prevention and treatment of various diseases. Generally, the harvest time and age of ginseng have been regarded as important factors determining the efficacy of ginseng. However, most studies have mainly focused on the root of ginseng, while studies on other parts of ginseng such as its berry have been relatively limited. Thus, the aim of this study iss to determine effects of harvest time on yields, phenolics/ginsenosides contents, and the antioxidant/anti-elastase activities of ethanol extracts of three- and four-year-old ginseng berry. In both three- and fourfour-year-old ginseng berry extracts, antioxidant and anti-elastase activities tended to increase as berries ripen from the first week to the last week of July. Liquid chromatography-tandem mass spectrometry analysis has revealed that contents of ginsenosides except Rg1 tend to be the highest in fourfour-year-old ginseng berries harvested in early July. These results indicate that biological activities and ginsenoside profiles of ginseng berry extracts depend on their age and harvest time in July, suggesting the importance of harvest time in the development of functional foods and medicinal products containing ginseng berry extracts. To the best of our knowledge, this is the first report on the influence of harvest time on the biological activity and ginsenoside contents of ginseng berry extracts.

Suppression of PMA-induced human fibrosarcoma HT-1080 invasion and metastasis by kahweol via inhibiting Akt/JNK1/2/p38 MAPK signal pathway and NF-κB dependent transcriptional activities.

Coffee is one of the widely sales beverage worldwide and contains numerous phytochemicals that are beneficial to health. Kahweol acetate (KA), a coffee-specific diterpene, exhibits anti-tumoric properties in human tumoric cells. However, the effect of KA on the metastasis and invasion of cancer cells and the underlying mechanisms remain unclear. The objectives of this study were to estimate the anti-tumor activity of KA and reveal the possible molecular mechanisms. KA markedly inhibited the cell proliferation enhanced by phorbol 12-myristate 13-acetate (PMA) in human fibrosarcoma cells. As well as, KA attenuated PMA-induced cell migration and invasion in a concentration-dependent manner. KA suppressed PMA-enhanced activation of matrix metalloproteinase-9 (MMP-9) through suppression of nuclear factor kappa B (NF-κB) activation. KA repressed the PMA-induced phosphorylation of Akt, c-Jun N-terminal kinase (JNK) 1/2, and p38 MAPK, which are signaling molecules upstream of MMP-9 expression. In summary, we demonstrated that the anti-tumor effects of KA might occur through the inhibition of Akt/JNK1/2/p38 MAPK phosphorylation and downregulation of NF-κB activation, leading to a decrease in MMP-9 expression. Thus, KA is a useful chemotherapeutic agent that may contribute to prevent to the metastatic tumor.

Saponins from the roots of Platycodon grandiflorum ameliorate high fat diet-induced non-alcoholic steatohepatitis.

Platycodon grandiflorum has been healthy effects due to its various nutritious compounds and is considered as a functional food. Platycodon grandiflorum root-derived saponins (CKS) have been reported to show a variety of effects including anti-inflammatory and anti-oxidative activity. Although CKS have been studied on various bioactivities, the inhibitory effect of CKS on non-alcoholic steatohepatitis (NASH) is not examined. In this study, the inhibitory effects on HFD-induced NASH by CKS were determined. CKS suppressed HFD-induced hepatic lipid peroxidation level, collagen deposition, pro-fibrogenic and pro-inflammatory cytokines expression. CKS treatment suppressed HFD-induced COX-2 expression via inhibition of NF-κB p65 nuclear translocation and IκBα degradation. CKS treatment restored HFD-reduced Nrf2-mediated antioxidant enzymes expression. Furthermore, CKS treatment reinstated HFD-reduced peroxisomal proliferator-activated receptor alpha (PPARα)-regulated acyl-coA oxidase and carnitine-palmitoyl-coA transferase-1 expression. These findings suggest that CKS reduces HFD-induced NASH by up-regulation of Nrf2-mediated anti-oxidant enzymes and PPARα-regulated fatty acid oxidation.

Ethanol extract of Lithospermum erythrorhizon Sieb. et Zucc. promotes osteoblastogenesis through the regulation of Runx2 and Osterix.

Bone remodeling and homeostasis are largely the result of the coordinated action of osteoblasts and osteoclasts. Osteoblasts are responsible for bone formation. The differentiation of osteoblasts is regulated by the transcription factors, Runx2 and Osterix. Natural products of plant origin are still a major part of traditional medicinal systems in Korea. The root of Lithospermum erythrorhizon Sieb. et Zucc. (LR), the purple gromwell, is an herbal medicine used for inflammatory and infectious diseases. LR is an anti-inflammatory and exerts anticancer effects by inducing the apoptosis of cancer cells. However, the precise molecular signaling mechanisms of osteoblastogenesis as regards LR and osteoblast transcription are not yet known. In this study, we investigated the effects of ethanol (EtOH) extract of LR (LES) on the osteoblast differentiation of C2C12 myoblasts induced by bone morphogenetic protein 4 (BMP4) and the potential involvement of Runx2 and Osterix in these effects. We found that the LES exhibited an ability to induce osteoblast differentiation. LES increased the expression of the osteoblast marker, alkaline phosphatase (ALP), as well as its activity, as shown by ALP staining and ALP activity assay. LES also increased mineralization, as shown by Alizarin Red S staining. Treatment with LES increased the protein levels (as shown by immunoblotting), as well as the transcriptional activity of Runx2 and Osterix and enhanced osteogenic activity. These results suggest that LES modulates osteoblast differentiation at least in part through Runx2 and Osterix.

Saponins, especially platyconic acid A, from Platycodon grandiflorum reduce airway inflammation in ovalbumin-induced mice and PMA-exposed A549 cells.

We investigated the inhibitory effects of Platycodon grandiflorum root-derived saponins (Changkil saponins: CKS) on ovalbumin-induced airway inflammation in mice. CKS suppressed leukocytes number, IgE, Th1/Th2 cytokines, and MCP-1 chemokine secretion in bronchoalveolar lavage fluid. Also, ovalbumin-increased MUC5AC, MMP-2/9, and TIMP-1/-2 mRNA expression, NF-κB activation, leukocytes recruitment, and mucus secretion were inhibited by CKS treatment. Moreover, the active component of CKS, platyconic acid A (PA), suppressed PMA-induced MUC5AC mRNA expression (from 2.1 ± 0.2 to 1.1 ± 0.1) by inhibiting NF-κB activation (from 2.3 ± 0.2 to 1.2 ± 0.1) via Akt (from 3.7 ± 0.3 to 2.1 ± 0.2) (p < 0.01) in A549 cells. Therefore, we demonstrate that CKS or PA suppressed the development of respiratory inflammation, hyperresponsiveness, and remodeling by reducing allergic responses, and they may be potential herbal drugs for allergen-induced respiratory disease prevention.

Platycodon grandiflorum root-derived saponins attenuate atopic dermatitis-like skin lesions via suppression of NF-κB and STAT1 and activation of Nrf2/ARE-mediated heme oxygenase-1.

PURPOSE: The consequences of precipitously rising allergic skin inflammation rates worldwide have accelerated the risk of atopic dermatitis (AD). Natural product-based agents with good efficacy and low risk of side effects offer promising prevention and treatment strategies for inflammation-related diseases. We have already reported that Platycodon grandiflorum root-derived saponins (Changkil saponins, CKS) have many pharmacological effects, including anti-inflammatory and anti-allergic effects, but its influence on AD remains unclear. Therefore, we evaluated the inhibitory effect of CKS, mainly platycodin D, on AD-like skin symptoms in mice and the possible mechanisms in cells. METHODS: Mice were sensitized and challenged with 2,4-dinitrochlorobenzene (DNCB). Four weeks after challenge, mice were treated with oral administration of CKS for 4 weeks. In addition, cells were used to evaluate the effect of CKS, mainly platycodin D, on the TARC expression regulated mechanism. RESULTS: CKS attenuated DNCB-induced dermatitis severity, serum levels of IgE and TARC, and mRNA expression of TARC, TNF-α, IFN-γ, IL-4, IL-5, and IL-13 in mice. Histopathological examination showed reduced thickness of the epidermis/dermis and dermal infiltration of inflammatory cells and mast cells in the ears. Moreover, CKS and platycodin D inhibited TNF-α/IFN-γ-induced TARC expression through the suppression of NF-κB and STAT1 and induction of Nrf2/ARE-mediated hemeoxygenase-1 (HO-1) expression in cells. CONCLUSION: We suggest that CKS and platycodin D inhibited the development of AD-like skin symptoms by regulating cytokine mediators and may be an effective alternative therapy for AD-like skin symptoms.

Saponins from the roots of Platycodon grandiflorum suppresses TGFß1-induced epithelial-mesenchymal transition via repression of PI3K/Akt, ERK1/2 and Smad2/3 pathway in human lung carcinoma A549 cells.

Transforming growth factor ß (TGFß) is a multifunctional cytokine that induces growth arrest, tissue fibrosis, and epithelial-mesenchymal transition (EMT) through activation of Smad and non-Smad signaling pathways. EMT is the differentiation switch by which polarized epithelial cells differentiate into contractile and motile mesenchymal cells. Our previous studies have shown that saponins from the roots of Platycodon grandiflorum (CKS) have antiinflammatory, antioxidant, antimetastatic, and hepatoprotective effects. In this study, we investigated the inhibitory effect of CKS on TGFß1-induced alterations characteristic of EMT in human lung carcinoma A549 cells. We found that CKS-treated cells displayed inhibited TGFß1-mediated E-cadherin downregulation and Vimentin upregulation and also retained epithelial morphology. Furthermore, TGFß1-increased Snail expression, a repressor of E-cadherin and an inducer of the EMT, was reduced by CKS. CKS inhibited TGFß1-induced phosphorylation of Akt, ERK1/2, and glycogen synthase kinase-3ß (GSK-3ß). Inhibition of PI3K/Akt and ERK1/2 also blocked TGFß1-induced GSK-3ß phosphorylation and Snail activation. Furthermore, TGFß1-increased Snail expression was reduced by selective inhibitors of Akt and ERK1/2. Moreover, CKS treatment attenuated TGFß1-induced Smad2/3 phosphorylation and upregulated Smad7 expression. These results indicate that pretreatment with the CKS inhibits the TGFß1-induced EMT through PI3K/Akt, ERK1/2, GSK-3ß and Smad2/3 in human lung carcinoma cells.

Antitumor efficacy of piperine in the treatment of human HER2-overexpressing breast cancer cells.

Piperine is a bioactive component of black pepper, Piper nigrum Linn, commonly used for daily consumption and in traditional medicine. Here, the molecular mechanisms by which piperine exerts antitumor effects in HER2-overexpressing breast cancer cells was investigated. The results showed that piperine strongly inhibited proliferation and induced apoptosis through caspase-3 activation and PARP cleavage. Furthermore, piperine inhibited HER2 gene expression at the transcriptional level. Blockade of ERK1/2 signaling by piperine significantly reduced SREBP-1 and FAS expression. Piperine strongly suppressed EGF-induced MMP-9 expression through inhibition of AP-1 and NF-κB activation by interfering with ERK1/2, p38 MAPK, and Akt signaling pathways resulting in a reduction in migration. Finally, piperine pretreatment enhanced sensitization to paclitaxel killing in HER2-overexpressing breast cancer cells. Our findings suggest that piperine may be a potential agent for the prevention and treatment of human breast cancer with HER2 overexpression.

Saponins from Platycodon grandiflorum inhibit hepatic lipogenesis through induction of SIRT1 and activation of AMP-activated protein kinase in high-glucose-induced HepG2 cells.

Saponins from the roots of Platycodon grandiflorum (Changkil saponins, CKS) have antioxidant and hepatoprotective properties. This study investigated the effects of CKS on AMP-activated protein kinase (AMPK) activation and hepatic lipogenesis in HepG2 cells. CKS suppressed high-glucose-induced lipid accumulation and inhibited high-glucose-induced fatty acid synthase (FAS) and sterol regulatory element binding protein-1c (SREBP-1c) expression in HepG2 cells. Moreover, the use of a pharmacological AMPK inhibitor revealed that AMPK is essential for the suppression of SREBP-1c expression in CKS-treated cells. Finally, the activation of calcium/calmodulin-dependent kinase kinase ß (CaMKKß) and SIRT1 was necessary for CKS-enhanced activation of AMPK. These results indicate that CKS prevents lipid accumulation in HepG2 cells by blocking the expression of SREBP-1c and FAS through SIRT1 and CaMKKß/AMPK activation. Using CKS to target AMPK activation may provide a promising approach for the prevention lipogenesis.

Cultivated ginseng inhibits 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in NC/Nga mice and TNF-α/IFN-γ-induced TARC activation in HaCaT cells.

Ginseng contains many bioactive constituents, including various ginsenosides that are believed to have anti-allergic, anti-oxidant, and immunostimulatory activities; however, its effects on atopic dermatitis (AD) remain unclear. In the current study, we hypothesized that cultivated ginseng (CG) would inhibit 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in NC/Nga mice by regulating the T helper (Th)1/Th2 balance. Also, CG inhibits TNF-α/IFN-γ-induced thymus- and activation-regulated chemokine (TARC) expression through nuclear factor-kappa B (NF-κB)-dependent signaling in HaCaT cells. CG ameliorated DNCB-induced dermatitis severity, serum levels of IgE and TARC, and mRNA expression of TARC, TNF-α, IFN-γ, IL-4, IL-5, and IL-13 in mice. Histopathological examination showed reduced thickness of the epidermis/dermis and dermal infiltration of inflammatory cells in the ears. Furthermore, CG suppressed the TNF-α/IFN-γ-induced mRNA expression of TARC in HaCaT cells. CG inhibited TNF-α/IFN-γ-induced NF-κB activation. These results suggest that CG inhibited the development of the AD-like skin symptoms by modulating Th1 and Th2 responses in the skin lesions in mice and TARC expression by suppressing TNF-α/IFN-γ-induced NF-κB activation in keratinocytes, and so may be a useful tool in the therapy of AD-like skin symptoms.

Reversal of P-glycoprotein-mediated multidrug resistance is induced by mollugin in MCF-7/adriamycin cells.

P-glycoprotein (P-gp), an important efflux transporter, is encoded by the MDR1 class of genes and is a central element of the multidrug resistance (MDR) phenomenon in cancer cells. In the present study, we investigated whether mollugin, purified from roots of Rubica cordifolia L., down-regulated MDR1 expression in MCF-7/adriamycin (MCF-7/adr) cells, a human breast multidrug-resistant cancer cell line. Mollugin treatment significantly inhibited MDR1 expression by blocking MDR1 transcription. Mollugin treatment also significantly increased intracellular accumulation of the fluorescently-tagged P-gp substrate, rhodamine-123. The suppression of MDR1 promoter activity and protein expression was mediated through mollugin-induced activation of AMP-activated protein kinase (AMPK). Furthermore, mollugin inhibited MDR1 expression through the suppression of NF-κB and CREB activation. Interestingly, mollugin also inhibited COX-2 expression. These results suggest that mollugin treatment enhanced suppression of P-gp expression by inhibiting the NF-κB signaling pathway and COX-2 expression, as well as attenuating CRE transcriptional activity through AMPK activation.

S-allyl cysteine attenuates free fatty acid-induced lipogenesis in human HepG2 cells through activation of the AMP-activated protein kinase-dependent pathway.

S-Allyl cysteine (SAC), a nontoxic garlic compound, has a variety of pharmacological properties, including antioxidant and hepatoprotective properties. In this report, we provide evidence that SAC prevented free fatty acid (FFA)-induced lipid accumulation and lipotoxicity in hepatocytes. SAC significantly reduced FFA-induced generation of reactive oxygen species, caspase activation and subsequent cell death. Also, SAC mitigated total cellular lipid and triglyceride accumulation in steatotic HepG2 cells. SAC significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in HepG2 cells. Additionally, SAC down-regulated the levels of sterol regulatory element binding protein-1 (SREBP-1) and its target genes, including ACC and fatty acid synthase. Use of a specific inhibitor showed that SAC activated AMPK via calcium/calmodulin-dependent kinase kinase (CaMKK) and silent information regulator T1. Our results demonstrate that SAC activates AMPK through CaMKK and inhibits SREBP-1-mediated hepatic lipogenesis. Therefore, SAC has therapeutic potential for preventing nonalcoholic fatty liver disease.

Platycodi Radix attenuates dimethylnitrosamine-induced liver fibrosis in rats by inducing Nrf2-mediated antioxidant enzymes.

The purpose of this study was to investigate the anti-fibrotic effects of the aqueous extract of the Platycodi Radix root (Changkil: CK) on dimethylnitrosamine (DMN)-induced liver fibrosis in rats. DMN treatment for 4 weeks led to marked liver fibrosis as assessed by serum biochemistry, histopathological examination, and hepatic lipid peroxidation and collagen content. CK significantly inhibited DMN-induced increases in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, fibrosis score, and hepatic malondialdehyde and collagen content. CK also inhibited DMN-induced reductions in rat body and liver weights. Reverse transcription polymerase chain reaction (RT-PCR) and western blot analyses revealed that CK inhibited DMN-induced increases in matrix metalloproteinase-13 (MMP-13), tissue inhibitor of metalloproteinase-1 (TIMP-1), and tumor necrosis factor-α (TNF-α) mRNA, and collagen type I and α-smooth muscle actin protein. DMN-induced cyclooxygenase-2 (COX-2) expression and nuclear factor-kappa B (NF-κB) activation was reduced by CK treatment. Furthermore, CK induced activation of nuclear erythroid 2-related factor 2 (Nrf2)-mediated antioxidant enzymes such as γ-glutamylcysteine synthetase (γ-GCS), heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and glutathione-S-transferase (GST) in HepG2 cells. These results demonstrated that CK attenuates DMN-induced liver fibrosis through the activation of Nrf2-mediated antioxidant enzymes.

Inhibitory effect of dihydroartemisinin against phorbol ester-induced cyclooxygenase-2 expression in macrophages.

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua L., has recently been shown to possess antitumor activity in various cancer cells. However, the effect of anti-inflammatory potentials of DHA in murine macrophage RAW 264.7 cells has not been studied. The present study investigated the effect of COX-2 and molecular mechanisms by DHA in PMA stimulated RAW 264.7 cells. DHA dose-dependently decreased PMA-induced COX-2 expression and PGE2 production, as well as COX-2 promoter-driven luciferase activity. Additionally, DHA decreased luciferase activity of COX-2 regulation-related transcription factors including NF-κB, AP-1, C/EBP and CREB. DHA also remarkably reduced PMA-induced p65, C/EBPß, c-jun and CREB nuclear translocation. Furthermore, DHA evidently inhibited PMA-induced phosphorylation of AKT and the MAP Kinases, such as ERK, JNK and p38. Taken together, our data indicated that DHA effectively attenuates COX-2 production via down-regulation of AKT and MAPK pathway, revealing partial molecular basis for the anti-inflammatory properties of DHA.

Phillyrin attenuates high glucose-induced lipid accumulation in human HepG2 hepatocytes through the activation of LKB1/AMP-activated protein kinase-dependent signalling.

Phillyrin, an active constituent found in many medicinal plants and certain functional foods, has anti-obesity activity in vivo. The aim of our study was to provide new data on the molecular mechanism(s) underlying the role of phillyrin in the prevention of high glucose-induced lipid accumulation in human HepG2 hepatocytes. We found that phillyrin suppressed high glucose-induced lipid accumulation in HepG2 cells. Phillyrin strongly inhibited high glucose-induced fatty acid synthase (FAS) expression by modulating sterol regulatory element-binding protein-1c (SREBP-1c) activation. Moreover, use of the pharmacological AMP-activated protein kinase (AMPK) inhibitor compound C revealed that AMPK is essential for suppressing SREBP-1c expression in phillyrin-treated cells. Finally, we found that liver kinase B1 (LKB1) phosphorylation is required for the phillyrin-enhanced activation of AMPK in HepG2 hepatocytes. These results indicate that phillyrin prevents lipid accumulation in HepG2 cells by blocking the expression of SREBP-1c and FAS through LKB1/AMPK activation, suggesting that phillyrin is a novel AMPK activator with a role in the prevention and treatment of obesity.

Cultivated ginseng suppresses ultraviolet B-induced collagenase activation via mitogen-activated protein kinases and nuclear factor κB/activator protein-1-dependent signaling in human dermal fibroblasts.

Cultivated ginseng (CG) (Panax ginseng C.A. Meyer), an herb used in Korean herbal medicine, has been widely used in China and Japan to treat fatigue and to enhance resistance to many diseases. It contains many bioactive constituents, including various ginsenosides that are believed to have antioxidant, immunostimulatory, and antiaging activities. Previous studies have revealed that treatment with Panax ginseng is significantly associated with reduced photoaging, but the underlying mode of action has not been elucidated. In this study, we hypothesized that CG inhibits ultraviolet B (UVB)-induced collagenase activation through mitogen-activated protein kinases (MAPKs) and nuclear factor κB (NF-κB)/activator protein-1 (AP-1)-dependent signaling in human skin fibroblasts. HS68 cells were treated with CG, followed by irradiation with UVB. Those effects were assessed by semiquantitative polymerase chain reaction, Western blotting, and enzymic activity assays. We found that CG increased cell viability and inhibited the production of reactive oxygen species in HS68 cells exposed to UVB irradiation. Pretreatment of HS68 cells with CG inhibited UVB-induced production of matrix metalloproteinase (MMP) 1 and MMP-13. Western blot analysis further revealed that CG markedly suppressed the enhancement of collagen degradation in UVB-exposed HS68 cells. Cultivated ginseng also suppressed UVB-induced activation of NF-κB, c-Jun, and c-Fos and the phosphorylation of MAPKs, which are upstream modulators of NF-κB and AP-1. These results indicate that CG inhibits UVB-induced collagenolytic MMP production by interfering with MAPK/AP-1 and NF-κB signaling and thus may be useful in the prevention and treatment of skin photoaging.

Inhibitory effect of Psidium guajava water extract in the development of 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice.

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory skin disease associated with eczematous symptoms and IgE hyperproduction. Psidium guajava is an important food crop and medicinal plant with anti-oxidant, anti-inflammatory, and anti-allergic activities, supporting its traditional uses. Our previous studies have shown that P. guajava extract inhibits Th2 chemokine expression by suppressing the activation of NF-κB and STAT1 co-stimulated with TNF-α and INF-γ. In this study, we investigated the inhibitory effect of P. guajava water extract (PGW) on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in NC/Nga mice. Treatment of cream containing PGW onto DNCB-induced AD-like skin lesions in NC/Nga mice ameliorated lesion intensity scores, levels of IgE, thymus and activation-regulated chemokine (TARC), TNF-α, and IL-4 in serum and ears. In contrast, PGW increased level of the immunosuppressive cytokine IL-10. Histological analyses demonstrated decreased thickening of the epidermis/dermis as well as dermal infiltration by inflammatory cells. These results suggest that cream containing PGW may be a potential therapeutic modality for AD and adjunctive agent to control pruritus in AD.

Platycodi Radix suppresses development of atopic dermatitis-like skin lesions.

Platycodi Radix has been used to treat chronic diseases, such as bronchitis, asthma, and hyperlipidemia. In this study, we examined the effect of an aqueous extract, Changkil (CK), from the root of Platycodi Radix on 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions. Administration of CK onto DNCB-induced AD-like skin lesions in NC/Nga mice ameliorated lesion intensity scores, levels of IgE, thymus and activation-regulated chemokine (TARC), TNF-α, and IL-4 in serum and ears. In contrast, CK increased level of the immunosuppressive cytokine IL-10. Histopathological examination showed reduced thickness of the epidermis/dermis and dermal infiltration of inflammatory cells in the ears. CK also suppressed TNF-α/IFN-γ-induced mRNA expression and production of TARC in HaCaT cells. CK exerts beneficial effects on AD symptoms, suggesting that CK is an effective potential therapeutic agent for AD.

Purple sweet potato anthocyanins attenuate hepatic lipid accumulation through activating adenosine monophosphate-activated protein kinase in human HepG2 cells and obese mice.

Purple sweet potato is a functional food rich in anthocyanins that possess disease-preventive properties. Anthocyanins are known to possess potent antidiabetic properties. However, the effect of the anthocyanin fraction (AF) from purple sweet potato on hepatic lipid metabolism remains unclear. Our hypothesis is that AF inhibits hepatic lipid accumulation through the activation of adenosine monophosphate-activated protein kinase (AMPK) signaling pathways in vitro and in vivo. In this study, we evaluated body weight, liver histology, and hepatic lipid content in high-fat diet (HFD)-fed ICR mice treated with AF. In addition, we characterized the underlying mechanism of AF's effects in HepG2 hepatocytes through Western blot analysis. Anthocyanin fraction (200 mg/kg per day) reduced weight gain and hepatic triglyceride accumulation and improved serum lipid parameters in mice fed an HFD for 4 weeks. Anthocyanin fraction significantly increased the phosphorylation of AMPK and acetyl-coenzyme A carboxylase (ACC) in the liver and HepG2 hepatocytes. In addition, AF down-regulated the levels of sterol regulatory element-binding protein 1 and its target genes including ACC and fatty acid synthase (FAS). The specific AMPK inhibitor compound C attenuated the effects of AF on the expression of lipid metabolism-related proteins such as SREBP-1 and FAS in HepG2 hepatocytes. The beneficial effects of AF on HFD-induced hepatic lipid accumulation are thus mediated through AMPK signaling pathways, suggesting a potential target for the prevention of obesity.

Saponins from the roots of Platycodon grandiflorum suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and NF-κB/AP-1-dependent signaling in HaCaT cells.

Saponins from the roots of Platycodon grandiflorum (CKS) have been shown to exhibit many pharmacological activities, including anti-cancer and anti-inflammatory activities and antioxidant effects. However, anti-skin photoaging effects of CKS have not yet been reported. In this study, we investigated the protective effects of CKS against UVA damage on immortalized human keratinocytes (HaCaT). We then explored the inhibitory effects of CKS on UVA-induced MMP-1 and investigated the molecular mechanism underlying those effects. CKS increased the cell viability and inhibited reactive oxygen species (ROS) production in HaCaT cells exposed to UVA irradiation. Pre-treatment of HaCaT cells with CKS inhibited UVA-induced production of MMP-1 and MMP-9. In addition, CKS decreased UVA-induced expression of the inflammatory cytokines IL-1ß and IL-6. Western blot analysis further revealed that CKS markedly suppressed the enhancement of collagen degradation in UVA-exposed HaCaT cells. CKS also suppressed UVA-induced activation of NF-κB or c-Jun and c-Fos, and the phosphorylation of MAPKs, which are upstream modulators of NF-κB and AP-1.