Sun Yeou Kim

Green tomato extract attenuates high-fat-diet-induced obesity through activation of the AMPK pathway in C57BL/6 mice

Obesity is a risk factor for numerous metabolic disorders. Recently, natural compounds that may be beneficial for improving obesity have received increasing attention. In this study, we investigated whether red and green tomato extracts attenuate high-fat-diet-induced obesity in C57BL/6 mice. The mice were maintained on a normal diet (ND) or high-fat diet (HFD) for 4 weeks and then fed ND, HFD, HFD plus 2% red tomato extract (RTE) or HFD plus 2% green tomato extract (GTE) for 13 weeks. The weekly food intakes among the groups were not significantly different. Body weight of mice fed HFD plus GTE was significantly decreased to the level of mice fed ND, but the body weight was only slightly reduced in mice fed HFD plus RTE. Epididymal adipose tissue and liver weights were significantly decreased in mice fed HFD plus GTE compared to those in HFD. Serum total cholesterol and low-density lipoprotein cholesterol levels in mice fed GTE were modestly reduced, and liver total cholesterol level was strongly decreased in HFD plus GTE-fed mice compared to that in HFD-fed mice. Adenosine-monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase phosphorylation in liver from HFD plus GTE-fed mice was significantly elevated, and HMG-CoA reductase expression was also significantly decreased. GTE strongly decreased the expression of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha and perilipin in the adipose tissue of mice fed HFD plus GTE. Our results indicate that the antiobesity effects of GTE may be associated with activation of the AMPK pathway.

A biphenyl derivative from the twigs of Chaenomeles speciosa

In our continuing search for bioactive constituents of Korean medicinal sources, we investigated an 80% MeOH extract of the twigs of Chaenomeles speciosa. Column chromatographic purification of the CHCl3 fraction resulted in the isolation of a new biphenyl derivative (1), along with four known biphenyl compounds (2-5) and six triterpenes (6-11). The chemical structure of the new compound was determined on the basis of spectroscopic analyses including 1D and 2D NMR data. Among isolates, compound 3 exhibited potent cytotoxic activities against SK-OV-3, SK-MEL-2, and XF498 cell lines (IC50=5.91, 4.22, and 6.28μM, respectively). Also, Compounds 9 and 10 showed strong anti-neuroinflammatory activities (IC50 2.38, and 6.70μM, respectively).

Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway.

Cholinergic activity plays a vital role in cognitive function, and is reduced in individuals with neurodegenerative diseases. Scopolamine, a muscarinic cholinergic antagonist, has been employed in many studies to understand, identify, and characterize therapeutic targets for Alzheimers disease (AD). Scopolamine-induced dementia is associated with impairments in memory and cognitive function, as seen in patients with AD. The current study aimed to investigate the molecular mechanisms underlying scopolamine-induced cholinergic neuronal dysfunction and the neuroprotective effect of lactucopicrin, an inhibitor of acetylcholine esterase (AChE). We investigated apoptotic cell death, caspase activation, generation of reactive oxygen species (ROS), mitochondrial dysfunction, and the expression levels of anti- and pro-apoptotic proteins in scopolamine-treated C6 cells. We also analyzed the expression levels of antioxidant enzymes and nuclear factor (erythroid-derived 2)-like 2 (NRF2) in C6 cells and neurite outgrowth in N2a neuroblastoma cells. Our results revealed that 1xa0h scopolamine pre-treatment induced cytotoxicity by increasing apoptotic cell death via oxidative stress-mediated caspase 3 activation and mitochondrial dysfunction. Scopolamine also downregulated the expression the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase, and the transcription factor NRF2. Lactucopicrin treatment protected C6 cells from scopolamine-induced toxicity by reversing the effects of scopolamine on those markers of toxicity. In addition, scopolamine attenuated the secretion of neurotrophic nerve growth factor (NGF) in C6 cells and neurite outgrowth in N2a cells. As expected, lactucopicrin treatment enhanced NGF secretion and neurite outgrowth. Our study is the first to show that lactucopicrin, a potential neuroprotective agent, ameliorates scopolamine-induced cholinergic dysfunction via NRF2 activation and subsequent expression of antioxidant enzymes.

Bombycis excrementum reduces amyloid-β oligomer-induced memory impairments, neurodegeneration, and neuroinflammation in mice.

Alzheimers disease (AD) is the most common cause of progressive dementia and is characterized by memory impairments, neuronal death, and neuroinflammation. AD-related pathophysiology is caused primarily by the presence of amyloid-β oligomers (AβO). Recently, an increased focus has been directed toward natural compounds or medicinal extracts for the treatment of AD. Extracts from Bombycis excrementum (BE), which is composed of various bioactive constituents and mulberry leaves (the preferred food of silkworms), have been shown to possess anti-inflammatory, anti-diabetic, and anti-oxidative effects. Additionally, mulberry leaves exert anti-amyloidogenic action and neuroprotective effects against Aβ peptides but it is unknown whether BE has a therapeutic effect on AD-related pathologies. Therefore, the present study examined whether BE inhibits AβO-induced memory loss, neuronal death, and inflammation. Behavioral tests revealed that BE significantly ameliorated AβO-induced memory impairments and inhibited AβO-induced neuronal loss in cultured cells and the brains of mice. BE also significantly inhibited microgliosis and astrogliosis following intra-hippocampal AβO injections in mice. Furthermore, BE significantly attenuated the release of nitric oxide from microglia and reduced AβO-induced S100-β cytokine release from activated astrocytes. These results suggest that BE may be a candidate agent for the treatment of AD.

Pharmacotherapeutic potential of ginger and its compounds in age-related neurological disorders

Age-related neurological disorders (ANDs), including neurodegenerative diseases, are multifactorial disorders with a risk that increases with aging. ANDs are generally characterized by common neuropathological conditions of the central nervous system, such as oxidative stress, neuroinflammation, and protein misfolding. Recently, efforts have been made to overcome ANDs because of the increase in age-dependent prevalence. Ginger, the rhizome of Zingiber officinale Roscoe, is a popular food spice and has a long history of use in traditional medicine for treating various disease symptoms. The structure-activity relationships of ginger phytochemicals show that ginger can be used to treat ANDs by targeting different ligand sites. This review shows that ginger and its constituents, such as 6-gingerol, 6-shogaol, 6-paradol, zingerone, and dehydrozingerone, are effective for ameliorating the neurological symptoms and pathological conditions of ANDs through by modulating cell death or cell survival signaling molecules. From this review, we conclude that the active ingredients in ginger have therapeutic potential in ANDs.

Isolation of bioactive biphenyl compounds from the twigs of Chaenomeles sinensis.

Investigation of the MeOH extract of Chaenomeles sinensis twigs resulted in the isolation of seven biphenyl compounds (1-7) including a new compound, chaenomin (1). The chemical structures of the isolated compounds were elucidated by extensive NMR data ((1)H and (13)C NMR, (1)H-(1)H COSY, HSQC and HMBC), specific optical rotation, and chemical reaction. Compounds 2 and 6 showed potent cytotoxic activities against four cancer cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15), and compound 7 exhibited potent anti-neuroinflammatory and NGF-potentiating activity.

Bioactive lignan constituents from the twigs of Sambucus williamsii.

As part of our ongoing search for bioactive constituents of natural Korean medicinal plants, three new lignan derivatives, sambucasinol A-C (1-3), together with 7 known compounds (4-10) were isolated from the twigs of Sambucus williamsii. The structures of these new compounds were determined by a combination of 1D and 2D NMR spectroscopic data analysis, as well as circular dichroism (CD) spectroscopy studies. Here, we evaluated the anti-inflammatory effects of 1-10 in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Compounds 1-3 exhibited significant inhibitory effects on nitric oxide production in LPS-activated BV-2 cells, with IC50 values of 6.82, 7.04, and 14.70 μM, respectively. Additionally, we evaluated the effects of compounds 1-10 on NGF induction in a C6 rat glioma cell line. Compounds 1-3 upregulated NGF secretion to 183.95 ± 2.63%, 153.99 ± 5.15%, and 155.96 ± 5.15%, respectively, without any significant cell toxicity. Moreover, all isolates were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and XF498 cell lines. Compounds 1-3 showed consistent cytotoxicity against the four human cell lines, with IC50 values in the range of 11.07-19.62 μM.

Sesquiterpene derivatives from marine sponge Smenospongia cerebriformis and their anti-inflammatory activity

Using various chromatographic methods, five new sesquiterpene derivatives named smenohaimiens A-E (1-5) and five known, 19-hydroxy-polyfibrospongol B (6), ilimaquinone (7), dictyoceratin C (8), polyfibrospongol A (9), and polyfibrospongol B (10) were isolated from the marine sponge Smenospongia cerebriformis Duchassaing & Michelotti, 1864. Their structures were assigned by 1D, 2D NMR spectroscopic analysis, HR ESI MS, and calculations of the electron circular dichroism spectra. All compounds were evaluated for the inhibitory activity against NO production in lipopolysaccharide-stimulated in BV2 microglia cells. As the results, compound 7 significantly inhibited NO production with the IC50 value of 10.40±1.28µM. The remaining compounds showed moderate inhibitory NO production activities with IC50 values ranging from 24.37 to 30.43µM.

Extracts of Sorbus commixta and Geranium thunbergii inhibit Osteoclastogenesis and stimulate Chondrogenesis

Abstract This study was carried out to investigate the effect of Sorbus commixta (SC), Geranium thunbergii (GT) and their mixture (SC:GT=1:1, MIX) on inhibition of bone loss and chondral defect. To examine their activities, we measured the alkaline phosphatase (ALP) activity in human osteoblast-like MG-63 cells and performed tartrate-resistant acid phosphate (TRAP) staining in osteoclast differentiated from Raw264.7 cells. To investigate the influence on chondrocyte differentiation, we performed alcian-blue staining in chondrocyte differentiated from ATDC5 cells. All of SC, GT and MIX did not increase ALP activity in MG-63 cells. However, SC and mixture (SC:GT=1:1, MIX) significantly inhibited osteoclastic differentiation. And they also induced chondrocyte differentiation. These results suggest that SC and GT may have a potential for the treatment of bone loss and chondral defect by suppression of osteoclast differentiation and stimulation of chondrocyte differentiation. Therefore, clarification of their mechanisms and active components will be needed.

Pharmacological use of a novel scaffold, anomeric N , N- diarylamino tetrahydropyran: molecular similarity search, chemocentric target profiling, and experimental evidence

Rational drug design against a determined target (disease, pathway, or protein) is the main strategy in drug discovery. However, regardless of the main strategy, chemists really wonder how to maximize the utility of their new compounds by drug repositioning them as clinical drug candidates in drug discovery. In this study, we started our drug discovery “from curiosity in the chemical structure of a drug scaffold itself” rather than “for a specific target”. As a new drug scaffold, anomeric diarylamino cyclic aminal scaffold 1, was designed by combining two known drug scaffolds (diphenylamine and the most popular cyclic ether, tetrahydropyran/tetrahydrofuran) and synthesized through conventional Brønsted acid catalysis and metal-free α-C(sp3)–H functionalized oxidative cyclization. To identify the utility of the new scaffold 1, it was investigated through 2D and 3D similarity screening and chemocentric target prediction. The predicted proteins were investigated by an experimental assay. The scaffold 1 was reported to have an antineuroinflammatory agent to reduce NO production, and compound 10 concentration-dependently regulated the expression level of IL-6, PGE-2, TNF-α, ER-β, VDR, CTSD, and iNOS, thus exhibiting neuroprotective activity.