Meirols A-C: Bioactive Catecholic Compounds from the Marine-Derived Fungus Meira sp. 1210CH-42.

Three new catecholic compounds, named meirols A-C (2-4), and one known analog, argovin (1), were isolated from the marine-derived fungus Meira sp. 1210CH-42. Their structures were determined by extensive analysis of 1D, 2D NMR, and HR-ESIMS spectroscopic data. Their absolute configurations were elucidated based on ECD calculations. All the compounds exhibited strong antioxidant capabilities with EC50 values ranging from 6.01 to 7.47 µM (ascorbic acid, EC50 = 7.81 µM), as demonstrated by DPPH radical scavenging activity assays. In the α-glucosidase inhibition assay, 1 and 2 showed potent in vitro inhibitory activity with IC50 values of 184.50 and 199.70 µM, respectively (acarbose, IC50 = 301.93 µM). Although none of the isolated compounds exhibited cytotoxicity against one normal and six solid cancer cell lines, 1 exhibited moderate cytotoxicity against the NALM6 and RPMI-8402 blood cancer cell lines with GI50 values of 9.48 and 21.00 µM, respectively. Compound 2 also demonstrated weak cytotoxicity against the NALM6 blood cancer cell line with a GI50 value of 29.40 µM.

Streptinone, a New Indanone Derivative from a Marine-Derived Streptomyces massiliensis, Inhibits Particulate Matter-Induced Inflammation.

Inflammatory diseases caused by air pollution, especially from particulate matter (PM) exposure, have increased daily. Accordingly, attention to treatment or prevention for these inflammatory diseases has grown. Natural products have been recognized as promising sources of cures and prevention for not only inflammatory but also diverse illnesses. As part of our ongoing study to discover bioactive compounds from marine microorganisms, we isolated streptinone, a new indanone derivative (1), along with three known diketopiperazines (2-4) and piericidin A (5), from a marine sediment-derived Streptomyces massiliensis by chromatographic methods. The structure of 1 was elucidated based on the spectroscopic data analysis. The relative and absolute configurations of 1 were determined by 1H-1H coupling constants, 1D NOESY, and ECD calculation. The anti-inflammatory activities of 1 were evaluated through enzyme-linked immunosorbent assay (ELISA), Western blot, and qPCR. Compound 1 suppressed the production of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1ß, by inhibiting the Toll-like receptor (TLR)-mediated nuclear factor kappa B (NF-κB) signaling pathway. Therefore, compound 1 could potentially be used as an agent in the prevention and treatment of diverse inflammatory disorders caused by particulate matter.

Dieckol Inhibits Autophagic Flux and Induces Apoptotic Cell Death in A375 Human Melanoma Cells via Lysosomal Dysfunction and Mitochondrial Membrane Impairment.

Dieckol is a natural brown algal-derived polyphenol and its cytotoxic potential against various types of cancer cells has been studied. However, the effects of dieckol on autophagy in cancer cells remain unknown. Here, we show that dieckol inhibits the growth of A375 human melanoma cells by inducing apoptotic cell death, which is associated with lysosomal dysfunction and the inhibition of autophagic flux. Dieckol induces autophagosome accumulation by inhibiting autophagosome-lysosome fusion. Moreover, dieckol not only triggers lysosomal membrane permeabilization, followed by an increase in lysosomal pH and the inactivation of cathepsin B and D, but also causes the loss of mitochondrial membrane potential. Importantly, a cathepsin D inhibitor partially relieved dieckol-induced mitochondrial membrane impairment and caspase-mediated apoptosis. Collectively, our findings indicate that dieckol is a novel autophagy inhibitor that induces apoptosis-mediated cell death via lysosomal dysfunction and mitochondrial membrane impairment in A375 human melanoma cells. This suggests the novel potential value of dieckol as a chemotherapeutic drug candidate for melanoma treatment.

The LAMMER kinase is involved in morphogenesis and response to cell wall- and DNA-damaging stresses in Candida albicans.

Dual specificity LAMMER kinase has been reported to be conserved across species ranging from yeasts to animals and has multiple functions. Candida albicans undergoes dimorphic switching between yeast cells and hyphal growth forms as its key virulence factors. Deletion of KNS1, which encodes for LAMMER kinase in C. albicans, led to pseudohyphal growth on YPD media and defects in filamentous growth both on spider and YPD solid media containing 10% serum. These cells exhibited expanded central wrinkled regions and specifically reduced peripheral filaments. Among the several stresses tested, the kns1Δ strains showed sensitivity to cell-wall and DNA-replicative stress. Under fluorescent microscopy, an increase in chitin decomposition was observed near the bud necks and septa in kns1Δ cells. When the expression levels of genes for cell wall integrity (CWI) and the DNA repair mechanism were tested, the kns1 double-deletion cells showed abnormal patterns compared to wild-type cells; The transcript levels of genes for glycosylphosphatidylinositol (GPI)-anchored proteins were increased upon calcofluor white (CFW) treatment. Under DNA replicative stress, the expression of MluI-cell cycle box binding factor (MBF)-targeted genes, which are expressed during the G1/S transition in the cell cycle, was not increased in the kns1 double-deletion cells. This strain showed increased adhesion to the surface of an agar plate and zebrafish embryo. These results demonstrate that Kns1 is involved in dimorphic transition, cell wall integrity, response to DNA replicative stress, and adherence to the host cell surface in C. albicans.

Plasmonic-Enhanced Luminescence Characteristics of Microscale Phosphor Layers on a ZnO Nanorod-Arrayed Glass Substrate.

We present a planar luminescent layer for glare-free, long-lifespan white light-emitting diodes (LEDs), with attractive light outputs. The novel and facile remote phosphor approach proposed in this work enhances luminescence properties by combining a waveguiding ZnO-based nanostructure with plasmonic Au nanoparticles. The system comprised a microscale yellow phosphor layer that is applied by simple printing onto an Au nanoparticle-dispersed ZnO nanorod array. This architecture resulted in a considerable enhancement in luminous efficacy of approximately 18% because of the combination of waveguide effects from the nanorod structure and plasmonic effects from the Au nanoparticles. Performance was optimized according to the length of the Zn nanorods and the concentration of Au. An optimal efficiency of ∼84.26 lm/W for a silicate phosphor-converted LED was achieved using long ZnO nanorods and an Au concentration of 12.5 ppm. The finite-difference time-domain method was successfully used to verify the luminous efficacy improvements in the Au nanoparticle-intervened nanostructures via the waveguiding and plasmonic effects.

Network approach of the conformational change of c-Src, a tyrosine kinase, by molecular dynamics simulation.

Non-receptor tyrosine kinase c-Src plays a critical role in numerous cellular signalling pathways. Activation of c-Src from its inactive to the active state involves large-scale conformational changes, and is controlled by the phosphorylation state of two major phosphorylation sites, Tyr416 and Tyr527. A detailed mechanism for the entire conformational transition of c-Src via phosphorylation control of Tyr416 and Tyr527 is still elusive. In this study, we investigated the inactive-to-active conformational change of c-Src by targeted molecular dynamics simulation. Based on the simulation, we proposed a dynamical scenario for the activation process of c-Src. A detailed study of the conformational transition pathway based on network analysis suggests that Lys321 plays a key role in the c-Src activation process.

Cellular properties of the fermented microalgae Pavlova lutheri and its isolated active peptide in osteoblastic differentiation of MG­63 cells.

Fermented microalgae Pavlova lutheri (P. lutheri), the product of Hansenula polymorpha fermentation, exhibited an increase in alkaline phosphatase (ALP) activity in MG­63 osteoblastic cells when compared to that of non­fermented P. lutheri. Fractionation of the fermented P. lutheri resulted in identification of the active peptide [peptide of P. lutheri fermentation (PPLF)] with the sequence of EPQWFL. PPLF significantly increased ALP release from MG­63 cells and mineralization in a dose­dependent manner. In addition, the intracellular levels of ALP and osteocalcin (OCN) proteins were augmented by PPLF treatment. To identify the molecular mechanism underlying the effect of PPLF on osteoblastic differentiation, the phosphorylation levels of the mitogen­activated protein kinases, p38, extracellular signal­regulated kinases 1/2 and Jun, and nuclear factor (NF)­κB were determined following PPLF treatment and the differences in expression were analyzed using p38 and NF­κB selective inhibitors. These results concluded that PPLF from fermented P. lutheri induced osteoblastic differentiation by increasing ALP and OCN release in MG­63 cells via the p38/p65 signaling pathway, indicating that PPLF supplement may be effective for therapeutic application in the field of bone health.

Apoptotic effect of demethoxyfumitremorgin C from marine fungus Aspergillus fumigatus on PC3 human prostate cancer cells.

Demethoxyfumitremorgin C, a secondary metabolite of the marine fungus, Aspergillus fumigatus, had been reported to demonstrate cytotoxic effect on mouse tsFT210 cells. However, no information is available regarding its functional mechanism and the chemo-sensitization effects on different kinds of human cancer cells. We found that treatment of demethoxyfumitremorgin C inhibited the cell viability of PC3 human advanced prostate cancer cells, induced apoptosis as determined by Annexin V/propidium iodide double staining, and decreased mitochondrial membrane potential. Demethoxyfumitremorgin C induced apoptosis was associated with downregulation of anti-apoptotic proteins: Ras, PI3K, Akt, Bcl-xL, and Bcl-2, and upregulation of pro-apoptotic Bax. Demethoxyfumitremorgin C activated caspase-3, -8, and -9, leading to PARP cleavage. Additionally, caspase inhibitors blocked demethoxyfumitremorgin C-induced apoptosis of PC3 cells. These results suggest that demethoxyfumitremorgin C from Aspergillus fumigatus inhibits the proliferation of PC3 human prostate cancer cells via the intrinsic (mitochondrial) and extrinsic pathway, followed by downstream events leading to apoptotic cell death. Demethoxyfumitremorgin C could therefore, serve as a useful agent to treat human advanced prostate cancer.

Induction of Nrf2-mediated phase II detoxifying/antioxidant enzymes in vitro by chitosan-caffeic acid against hydrogen peroxide-induced hepatotoxicity through JNK/ERK pathway.

Chemical modification of chitosan is a promising method for the improvement of biological activity. In this study, chitosan-caffeic acid (CCA) was prepared and its in vitro hepatoprotective ability against hydrogen peroxide-induced hepatic damage in liver cells was evaluated. Treatment with CCA (50-400 µg/mL) did not show cytotoxicity and also significantly (p < 0.05) recovered cell viability against 650 µM hydrogen peroxide-induced hepatotoxicity. CCA treatment attenuated reactive oxygen species generation and lipid peroxidation in addition to increasing cellular glutathione level in cultured hepatocytes. To validate the underlying mechanism, antioxidant and phase II detoxifying enzyme expressions, which are mediated by NF-E2-related factor 2 (Nrf2) activation, were analyzed and CCA treatment was found to increase the expression of superoxide dismutase-1 (SOD-1), glutathione reductase (GR), heme oxygenase-1 (HO-1), and NAD(P)H:quinine oxidoreductase 1 (NQO1). CCA treatment resulted in increased Nrf2 nuclear translocation. The phosphorylation of extracellular regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) by CCA treatment contributed to Nrf2 activation. Pharmacological blockade of ERK, JNK, and p38 MAPK revealed that SP600125 (JNK inhibitor) and PD98059 (ERK inhibitor) treatment reduced Nrf2 translocation into the nucleus while SB203580 (p38 inhibitor) exhibited weak inhibition. Collectively, CCA protects liver cells against hydrogen peroxide-induced injury and this ability is attributed to the induction of antioxidants and phase II detoxifying enzymes that are mediated by Nrf2 translocation via JNK/ERK signaling.

Hydroxyproline-containing collagen peptide derived from the skin of the Alaska pollack inhibits HIV-1 infection.

The human immunodeficiency virus (HIV) is a lentivirus that results in acquired immunodeficiency syndrome (AIDS). HIV treatment involving chemical therapeutic agents has improved the quality of life of HIV/AIDS patients. The present study demonstrates that a hydroxyproline-containing marine collagen peptide (APHCP) derived from Alaska pollack inhibits HIV­1 infection in the MT-4 human T cell­line. APHCP inhibited HIV-1IIIB-induced cell lysis, syncytia formation, reverse transcriptase activity and viral p24 production at non­cytotoxic concentrations; however, APHCP did not inhibit HIV­2ROD infection in MT­4 cells. This suggests that the anti­HIV activity of APHCP is specific to HIV­1. In addition, substitution of hydroxyproline residues in APHCP with prolines impaired its anti­HIV­1 activity, suggesting that the hydroxyl group of hydroxyprolines is required for the anti­HIV­1 activity of APHCP. These results suggested that the marine peptide APHCP may be a novel drug candidate in the development of next­generation therapeutic agents for the treatment of HIV/AIDS.

Inhibitory effects of dieckol on hypoxia-induced epithelial-mesenchymal transition of HT29 human colorectal cancer cells.

Hypoxia-induced epithelial-mesenchymal transition (EMT) has been identified as essential for tumor progression and metastasis. The present study examined the effects of an antioxidant, dieckol, on hypoxia­induced EMT in HT29 human colorectal cancer cells. HT29 cells were treated with a hypoxia­inducing agent, CoCl2, and an increase in the levels of intracellular reactive oxygen species (ROS) and various morphological changes, such as loss of cell­cell contact and aggressive cell migration were observed. CoCl2 also induced an increase in the expression of hypoxia­inducible factor 1α (HIF1α) and various mesenchymal­specific markers, including vimentin and snail family transcriptional repressor 1 (Snail1), and a decrease in the expression of E­cadherin, thus suggesting that CoCl2 induced EMT in HT29 cells. Conversely, the CoCl2­induced EMT of HT29 cells was suppressed following treatment with dieckol. In addition, ROS generation, EMT marker protein expression and intracellular localization, cell migration and cell invasion were attenuated following dieckol treatment. The findings of the present study suggested that dieckol may inhibit hypoxia­induced EMT in HT29 cells by regulating the levels of cellular ROS and protein expression levels downstream of the HIF1α signaling pathway. Therefore, dieckol has the potential to become an attractive therapeutic agent for the treatment of colorectal cancer.

Gallic Acid-g-Chitosan Modulates Inflammatory Responses in LPS-Stimulated RAW264.7 Cells Via NF-κB, AP-1, and MAPK Pathways.

Chitosan is a naturally occurring polysaccharide, which has exhibited antioxidant, antimicrobial, and anti-cancer activities among others. Modification of chitosan by grafting phenolic compounds is a good strategy for improvement of bioactivities of chitosan. We investigated the anti-inflammatory action of gallic acid-grafted-chitosan (GAC) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. GAC inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) by inhibiting inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 macrophages. GAC also suppressed the production and mRNA expression of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6). GAC inactivated nuclear factor-κB (NF-κB) via inhibiting the phosphorylation and degradation of the NF-κB inhibitor, IκB. In addition, GAC suppresses the activation of activator protein-1 (AP-1) through the phosphorylation of mitogen-activated protein kinase (MAPK) such as extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and c-Jun N-terminal kinase/stress-activated protein kinase (JNK). These results suggest that GAC has the potential anti-inflammatory action by downregulating transcriptional factors (NF-κB and AP-1) through MAPK signaling pathways.

Derivation of Neural Precursor Cells from Human Embryonic Stem Cells for DNA Methylomic Analysis.

Embryonic stem cells are self-renewing pluripotent cells with competency to differentiate into all three-germ lineages. Many studies have demonstrated the importance of genetic and epigenetic molecular mechanisms in the maintenance of self-renewal and pluripotency. Stem cells are under unique molecular and cellular regulations different from somatic cells. Proper regulation should be ensured to maintain their unique self-renewal and undifferentiated characteristics. Understanding key mechanisms in stem cell biology will be important for the successful application of stem cells for regenerative therapeutic medicine. More importantly practical use of stem cells will require our knowledge on how to properly direct and differentiate stem cells into the necessary type of cells. Embryonic stem cells and adult stem cells have been used as study models to unveil molecular and cellular mechanisms in various signaling pathways. They are especially beneficial to developmental studies where in vivo molecular/cellular study models are not available. We have derived neural stem cells from human embryonic stem cells as a model to study the effect of teratogen in neural development. We have tested commercial neural differentiation system and successfully derived neural precursor cells exhibiting key molecular features of neural stem cells, which will be useful for experimental application.

Role of AMP-Activated Protein Kinase (AMPK) in Smoking-Induced Lung Inflammation and Emphysema.

BACKGROUND: AMP-activated protein kinase (AMPK) not only functions as an intracellular energy sensor and regulator, but is also a general sensor of oxidative stress. Furthermore, there is recent evidence that it participates in limiting acute inflammatory reactions, apoptosis and cellular senescence. Thus, it may oppose the development of chronic obstructive pulmonary disease. METHODS: To investigate the role of AMPK in cigarette smoke-induced lung inflammation and emphysema we first compared cigarette smoking and polyinosinic-polycytidylic acid [poly(I:C)]-induced lung inflammation and emphysema in AMPKα1-deficient (AMPKα1-HT) mice and wild-type mice of the same genetic background. We then investigated the role of AMPK in the induction of interleukin-8 (IL-8) by cigarette smoke extract (CSE) in A549 cells. RESULTS: Cigarette smoking and poly(I:C)-induced lung inflammation and emphysema were elevated in AMPKα1-HT compared to wild-type mice. CSE increased AMPK activation in a CSE concentration- and time-dependent manner. 5-Aminoimidazole-4-carboxamide-1-ß-4-ribofuranoside (AICAR), an AMPK activator, decreased CSE-induced IL-8 production while Compound C, an AMPK inhibitor, increased it, as did pretreatment with an AMPKα1-specific small interfering RNA. CONCLUSION: AMPKα1-deficient mice have increased susceptibility to lung inflammation and emphysema when exposed to cigarette smoke, and AMPK appears to reduce lung inflammation and emphysema by lowering IL-8 production.

Production of α-amylase for the biosynthesis of gold nanoparticles using Streptomyces sp. MBRC-82.

Marine actinobacterial synthesis of gold nanoparticles has good potential to develop simple, cost-effective and eco-friendly methods for production of important biomaterials. In this context, gold nanoparticles have attracted considerable attention in recent years, owing to their various applications. In this paper, we report on the production of α-amylase for the extracellular synthesis of gold nanoparticles using Streptomyces sp. MBRC-82. Medium composition and culture conditions for α-amylase production were statistically optimized. Plackett-Burman design was employed to find out the optimal medium constituents and culture conditions to enhance α-amylase production. Box-Behnken design revealed that three independent variables namely soluble starch (5.8484 g), peptone (3.5191 g), and NaCl (0.3829) significantly influenced α-amylase production. The gold nanoparticles were characterized by ultraviolet-visible (UV-vis) spectrometer, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), and transmission electron microscopy (TEM). The particles synthesized using the optimized enzyme activity ranged from 20 to 80 nm with an average particle size of 40 nm and therefore can be extended to various medicinal applications.

Anti-HIV-1 activity of phlorotannin derivative 8,4‴-dieckol from Korean brown alga Ecklonia cava.

8,4‴-dieckol is a natural product which has been isolated from brown alga, Ecklonia cava. This polyphenolic compound is a phlorotannin derivative with a broad range of bioactivities. Its inhibitory activity on human immunodeficiency virus type-1 (HIV-1) was tested and the results indicated that 8,4‴-dieckol inhibited HIV-1 induced syncytia formation, lytic effects, and viral p24 antigen production at noncytotoxic concentrations. Furthermore, it was found that 8,4‴-dieckol selectively inhibited the activity of HIV-1 reverse trancriptase (RT) enzyme with 91% inhibition ratio at the concentration of 50 µM. HIV-1 entry was also inhibited by 8,4‴-dieckol. According to data from this study, 8,4‴-dieckol is an effective compound against HIV-1 with high potential for further studies. These results suggest that it might be used as a drug candidate for the development of new generation therapeutic agents, although further studies on the mechanism of inhibition should be addressed.

The role of peptides derived from Spirulina maxima in downregulation of FcεRI-mediated allergic responses.

SCOPE: Spirulina has been found suitable for use as a bioactive additive. It is an excellent source of protein that can be hydrolyzed into bioactive peptides. Two peptides LDAVNR (P1) and MMLDF (P2) purified from enzymatic hydrolysate of Spirulina maxima have been reported to be effective against early atherosclerotic responses. In this study, the intracellular mechanism involved in the downregulation of these peptides on high-affinity IgE receptor-mediated allergic reaction was further investigated. METHODS AND RESULTS: RBL-2H3 mast cells were pretreated with P1 or P2 and sensitized with dinitrophenyl-specific IgE antibody before stimulation of antigen dinitrophenyl-BSA. It was revealed that P1 and P2 exhibited significant inhibition on mast-cell degranulation via decreasing histamine release and intracellular Ca(2+) elevation. The inhibitory activity of P1 was found due to blockade of calcium- and microtubule-dependent signaling pathways. Meanwhile, the inhibition of P2 was involved in suppression of phospholipase Cγ activation and reactive oxygen species production. Moreover, the suppressive effects of P1 and P2 on generation of IL-4 were evidenced via depression of nuclear factor-κB translocation. CONCLUSION: These findings indicate that peptides P1 and P2 from S. maxima may be promising candidates of antiallergic therapeutics, contributing to development of bioactive food ingredients for amelioration of allergic diseases.

Seahorse-derived peptide suppresses invasive migration of HT1080 fibrosarcoma cells by competing with intracellular α-enolase for plasminogen binding and inhibiting uPA-mediated activation of plasminogen.

α-Enolase is a glycolytic enzyme and a surface receptor for plasminogen. α-Enolase-bound plasminogen promotes tumor cell invasion and cancer metastasis by activating plasmin and consequently degrading the extracellular matrix degradation. Therefore, α-enolase and plasminogen are novel targets for cancer therapy. We found that the amino acid sequence of a peptide purified from enzymatic hydrolysates of seahorse has striking similarities to that of α-enolase. In this study, we report that this peptide competes with cellular α-enolase for plasminogen binding and suppresses urokinase plasminogen activator (uPA)-mediated activation of plasminogen, which results in decreased invasive migration of HT1080 fibrosarcoma cells. In addition, the peptide treatment decreased the expression levels of uPA compared to that of untreated controls. These results provide new insight into the mechanism by which the seahorse-derived peptide suppresses invasive properties of human cancer cells. Our findings suggest that this peptide could emerge as a potential therapeutic agent for cancer.

Modified midi- and mini-multiplex PCR systems for mitochondrial DNA control region sequence analysis in degraded samples.

Two multiplex polymerase chain reaction (PCR) systems (Midiplex and Miniplex) were developed for the amplification of the mitochondrial DNA (mtDNA) control region, and the efficiencies of the multiplexes for amplifying degraded DNA were validated using old skeletal remains. The Midiplex system consisted of two multiplex PCRs to amplify six overlapping amplicons ranging in length from 227 to 267 bp. The Miniplex system consisted of three multiplex PCRs to amplify 10 overlapping short amplicons ranging in length from 142 to 185 bp. Most mtDNA control region sequences of several 60-year-old and 400-500-year-old skeletal remains were successfully obtained using both PCR systems and consistent with those previously obtained by monoplex amplification. The multiplex system consisting of smaller amplicons is effective for mtDNA sequence analyses of ancient and forensic degraded samples, saving time, cost, and the amount of DNA sample consumed during analysis.

ß-secretase inhibitory activity of phenolic acid conjugated chitooligosaccharides.

Eight kinds of phenolic acid conjugated chitooligosaccharides (COSs) were synthesized using hydroxyl benzoic acid and hydroxyl cinnamic acid. These phenolic acid conjugated-COSs with different substitution groups, including p-hydroxyl, 3,4-dihydroxyl, 3-methoxyl-4-hydroxyl and 3,5-dimethoxyl-4-hydroxy groups, were evaluated for their inhibitory activities against ß-site amyloid precursor protein (APP)-cleaving enzyme (BACE) and inhibited BACE with a ratio of 50.8%, 74.8%, 62.1%, 64.8% and 42.6%, respectively at the concentration of 1,000 µg/mL. BACE is a critical component to reduce the levels of Aß amyloid peptide in Alzheimer's disease (AD) which is based on the amyloid cascade theory in the brain, as this protease initiates the first step in Aß production. Among them, Caffeic acid conjugated-COS (CFA-COS) was further analysed to determine mode of inhibition of BACE and it showed non-competitive inhibition. Hence in this study, we suggest that CFA-COS derivatives have potential to be used as novel BACE inhibitors to reduce the risk of AD.