Saksit Nobsathian

Protective role of N-trans-feruloyltyramine against β-amyloid peptide-induced neurotoxicity in rat cultured cortical neurons

Enhanced oxidative stress and inflammation play important roles in the pathogenesis of Alzheimers disease (AD). Amyloid β-peptide (Aβ), a major component of amyloid plaques, is considered to have a causal role in the development and progress of AD by being the initiator of a pathological cascade leading to oxidative stress. The present study investigated the effect of N-trans-feruloyltyramine (NTF) purified from Polyalthia suberosa, an alkaloid shown to protect against oxidative stress and cell death. Pre-treatment of rat primary cortical cell cultures with 25-250μM NTF significantly attenuated 10μM Aβ(1-42)-induced neuronal death in a dose-dependent manner. Apoptotic cell death was demonstrated morphologically as well as by detection of the presence of activated caspase-3 and Bax, levels of which could be reduced by NTF pre-treatment. NTF also reduced production of reactive oxygen species induced by Aβ(1-42). These findings suggest that the protective effect of NTF against Aβ(1-42)-induced neuronal death might be due to its antioxidative property.

N-benzylcinnamide protects rat cultured cortical neurons from β-amyloid peptide-induced neurotoxicity.

The pathogenesis of Alzheimers disease involves an amyloid β-peptide (Aβ)-induced cascade of elevated oxidative damage and inflammation. The present study investigates the protective effects and the underlying mechanisms of N-benzylcinnamide (PT-3), purified from Piper submultinerve. Against Aβ-induced oxidative stress and inflammation in rat primary cortical cell cultures. Pre-treatment with 10-00nM PT-3 significantly attenuated neuronal cell death induced by 10μM Aβ1-42. PT-3 was found to enhance cell viability through a significant reduction in the level of reactive oxygen species, down-regulated expression of pro-apoptotic activated caspase-3 and Bax, increased expression of anti-apoptotic Bcl-2, and mitigation of Aβ-induced morphological alterations. Regarding its effects on inflammatory responses, PT-3 pre-treatment decreased the expression of pro-inflammatory cytokines IL-1β and IL-6. The mechanisms of PT-3 neuronal protection against inflammation may be associated with the mitogen-activated protein kinases (MAPK) pathway. Aβ1-42-induced phosphorylation of JNK and p38 MAPK was inhibited by pretreatment with PT-3 in a dose-dependent manner. However, phosphorylation of ERK1/2 was not affected by either PT-3 or Aβ1-42. PT-3 did not stimulate Akt phosphorylation, which was inhibited by Aβ1-42. These findings suggest that PT-3 protects neurons from Aβ1-42-induced neurotoxicity through its anti-apoptotic, anti-oxidative, and anti-inflammatory properties with inhibition of JNK and p38 MAPK phosphorylation as the potential underlying mechanism.

Potential role of N-benzylcinnamide in inducing neuronal differentiation from human amniotic fluid mesenchymal stem cells

Neurodegenerative disorders are characterized by chronic and progressive loss of neurons in structure and function related to aging, such as Alzheimers disease, the latter characterized by the degeneration of cholinergic neurons in basal forebrain connected to the cerebral cortex and hippocampus. Amniotic fluid mesenchymal stem cells (AF-MSCs) have been proposed as one of the candidates for stem cell therapy of nervous system disorders. This study demonstrates that incubation of AF-MSCs, obtained from 16 to 20 week pregnant women, with 10ng/ml bone morphogenetic protein (BMP)-9 for 48h in conditioned medium resulted in transdifferentiation to cholinergic neuronal-like cells. This phenomenon could also be obtained with N-benzylcinnamide (PT-3). Pre-treatment for 1h with 10nM PT-3 augmented BMP-9 transdifferentiation effect, elevated βIII-tubulin cell numbers and fluorescence intensity of immunoreactive ChAT, ameliorated BMP-9-related production of reactive oxygen species and enhanced anti-apoptosis status of the neuronal-like cells. The transdiffirentiation process was accompanied by increased p53 but decreased Notch1 and SIRT1 (p53 deacetylase) levels, and activation of p38, ERK1/2 MAPK, and PI3K/Akt pathways, in concert with inactivation of JNK, all of which were accentuated by PT-3 pre-treatment. These findings suggest that N-benzylcinnamide may provide a useful adjuvant in BMP-9-induced transdifferentiation of AFMSCs into ultimately cholinergic neurons.

A new conjugated amide-dimer from the aerial parts of Piper submultinerve

Bioassay-guided fractionation and purification of the aerial parts of Piper submultinerve led to the isolation of a new conjugated amide-dimer, submultinamide A (1), along with 11 known compounds. The structures were determined on the basis of spectroscopic methods. Among the tested compounds, pellitorine (2), guineensine (4), N-benzylcinnamide (6) and aristolactam BII (8) showed significant activities in the anti-syncytium assay using ΔTat/RevMC99 virus and 1A2 cell line system, whereas 2 was most active (EC50 35.1 µM and selectivity index 4.7). In the HIV-1 reverse transcriptase assay, only 4 was active with IC50 50.8 µM.

Holothuria scabra extracts exhibit anti-Parkinson potential in C. elegans: A model for anti-Parkinson testing

Objectives: Parkinsons disease (PD) is associated with aggregation of α-synuclein and selective death of dopaminergic (DA) neurons in the substantia nigra, thereby leading to cognitive and motor impairments. Nowadays, the drugs commonly used for PD treatment, such as levodopa, provide only symptomatic relief. Therefore, seeking new drugs against PD, especially from plants and marine organisms, is one of the major research areas to be explored. This study aimed to investigate the anti-Parkinson activity of the extracts from the sea cucumber, Holothuria scabra, by using Caenorhabditis elegans as a model. Methods: H. scabra was solvent-extracted and subdivided into six fractions including whole body-ethyl acetate (WBEA), body wall-ethyl acetate (BWEA), viscera-ethyl acetate (VIEA), whole body-butanol (WBBU), body wall-butanol (BWBU), and viscera-butanol (VIBU). The extracts were tested in C. elegans BZ555 strain expressing the green fluorescent protein (GFP) specifically in the DA neurons and NL5901 strain expressing human α-synuclein in the muscle cells. Results: WBEA, BWEA, and WBBU fractions of H. scabra extracts at 500 µg/ml significantly attenuated DA neuron-degeneration induced by selective cathecholamine neurotoxin 6-hydroxydopamine (6-OHDA) in the BZ555 strain. Moreover, the extracts also reduced α-synuclein aggregation and restored lipid content in NL5901, as well as improved food-sensing behavior and prolonged lifespan in the 6-OHDA-treated wild-type strain. Discussion: The study indicated that the H. scabra extracts have anti-Parkinson potential in the C. elegans model. These findings encourage further investigations on using the H. scabra extract, as well as its active constituent compounds, as a possible preventive and/or therapeutic intervention against PD.

Neuroprotection of N-benzylcinnamide on scopolamine-induced cholinergic dysfunction in human SH-SY5Y neuroblastoma cells

Alzheimers disease, a progressive neurodegenerative disease, affects learning and memory resulting from cholinergic dysfunction. Scopolamine has been employed to induce Alzheimers disease-like pathology in vivo and in vitro through alteration of cholinergic system. N-benzylcinnamide (PT-3), purified from Piper submultinerve, has been shown to exhibit neuroprotective properties against amyloid-β-induced neuronal toxicity in rat cortical primary cell culture and to improve spatial learning and memory of aged rats through alleviating oxidative stress. We proposed a hypothesis that PT3 has a neuroprotective effect against scopolamine-induced cholinergic dysfunction. PT-3 (125–200 nM) pretreatment was performed in human neuroblastoma SH-SY5Y cell line following scopolamine induction. PT-3 (125–200 nM) inhibited scopolamine (2 mM)-induced generation of reactive oxygen species, cellular apoptosis, upregulation of acetylcholinesterase activity, downregulation of choline acetyltransferase level, and activation of p38 and JNK signalling pathways. These findings revealed the underlying mechanisms of scopolamine-induced Alzheimers disease-like cellular dysfunctions, which provide evidence for developing drugs for the treatment of this debilitating disease.

The Possibility of Using Isolated Alkaloid Compounds and Crude Extracts of Piper retrofractum (Piperaceae) as Larvicidal Control Agents for Culex quinquefasciatus (Diptera: Culicidae) Larvae

Abstract Culex quinquefasciatus is a common domestic mosquito that is widespread in many areas of Thailand and serves as a southeastern vector of Japanese encephalitis. The present study investigated the acute toxicity of crude extracts and alkaloid compounds of Piper retrofractum (Piperales: Piperaceae) in Cx. quinquefasciatus third instar larvae. P. retrofractum was sequentially extracted using hexane, dichloromethane, ethyl acetate, and methanol, and the crude extracts were tested on mosquito larvae. Detoxification and neuroenzymes were analyzed to establish the mode of action. Acute toxicity was assessed on Poecilia reticulata (Cyprinodontiformes: Poeciliidae) to determine the possibility of toxicity in a nontarget species. Our results showed crude hexane extract had the highest toxicity in Cx. quinquefasciatus (0.9 ppm). Piperine and piperanine, which are alkaloid compounds from the crude hexane extract, showed LC50 values of 0.27 and 2.97 ppm, respectively, after 24 h of exposure. All the crude extracts showed low toxicity in P. reticulata compared with that in the mosquito larvae. The carboxylesterase, glutathione-S-transferase, and acetylcholinesterase activities in Cx. quinquefasciatus were reduced after treatment with all the extracts and the two alkaloid compounds.Thus, P. retrofractum shows larvicidal effects against Cx. quinquefasciatus and low toxicity for nontarget species. Thus, P. retrofractum could be a choice for controlling Cx. quinquefasciatus.

Development of pure certified reference material of stevioside

Pure stevioside was extracted from leaves of Stevia rebaudiana (Bertoni) to be used as a reference material in the instrument calibration or method validation process. The mass fraction was determined by comparison between the mass balance method and quantitative nuclear magnetic resonance (qNMR) spectroscopy. The impurities in the sample were analyzed by Karl Fischer titration for moisture content and thermogravimetric analysis for inorganic residue. Homogeneity, together with short term and long term stability, were also studied and the uncertainty was reported. The certified value of this mass fraction is 0.986 ± 0.0019 (k = 2) with 1 year stability.

Holothuria scabra extracts possess anti-oxidant activity and promote stress resistance and lifespan extension in Caenorhabditis elegans

&NA; Holothuria scabra is a sea cucumber that is mostly found in the Indo‐Pacific region including Thailand. Extracts from many sea cucumbers possess pharmacological activities proposed to benefit human health. In this study, we investigated the anti‐oxidant and anti‐ageing activities of extracts from H. scabra by using Caenorhabditis elegans as a model organism. Parts of H. scabra were solvent‐extracted and divided into nine fractions including whole body‐hexane (WBHE), whole body‐ethyl acetate (WBEA), whole body‐butanol (WBBU), body wall‐hexane (BWHE), body wall‐ethyl acetate (BWEA), body wall‐butanol (BWBU), viscera‐hexane (VIHE), viscera‐ethyl acetate (VIEA), and viscera‐butanol (VIBU). All fractions of the extracts were tested for anti‐oxidant activities by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) assays and for anti‐ageing effects by lifespan assays using C. elegans as a model. The results showed anti‐oxidant properties in all fractions with the highest activity shown by the DPPH assay in WBBU (EC50 = 3.12 ± 0.09 mg/ml), and by the ABTS assay in WBHE (EC50 = 0.31 ± 0.10 mg/ml). In lifespan assays the highest anti‐ageing effect was detected in WBBU‐ and BWEA‐treated C. elegans with increased mean lifespans of 8.12% and 4.77%, respectively. Furthermore, WBBU and BWEA‐treated C. elegans exhibited significantly higher resistance against heat shock and paraquat‐induced oxidative stresses than controls. By using LC‐MS/MS, both extracts were characterized to contain triterpene glycosides as the main bioactive components. To explore mechanisms of H. scabra extracts on longevity and stress resistance, worms with genetic mutations in anti‐ageing pathways were analyzed and showed that WBBU and BWEA did not prolong the lifespan of daf‐16, age‐1, sir‐2.1, jnk‐1, sek‐1, and osr‐1 mutants, suggesting that these genetic pathways are involved in mediating the anti‐ageing effects of the H. scabra extracts. Moreover, WBBU and BWEA enhanced the nuclear translocation of the FoxO/DAF‐16 transcription factor, and increased mRNA expression of this gene and its downstream targets sod‐3, hsp12.3, and hsp16.2. In conclusion, this study strongly demonstrates anti‐oxidant and anti‐ageing properties of H. scabra extracts containing triterpene glycosides, which, in the C. elegans model, may be mediated via the insulin/IGF‐1 signaling (IIS)‐DAF‐16 pathway. HighlightsH. scabra extracts exhibited anti‐oxidant activity and lifespan extension in C. elegansH. scabra extracts improved healthspan and resistance to thermal and oxidative stressesH. scabra extracts enhanced the nuclear translocation of DAF‐16 and increased expressions of sod‐3, hsp‐12.3, and hsp‐16.2Anti‐ageing effects of H. scabra extracts are mediated via the insulin/IGF‐1 signaling (IIS)‐DAF‐16 pathwayH. scabra extracts contained triterpene glycosides as major bioactive constituents

An antioxidant activity of the whole body of Holothuria scabra

BackgroundHolothuria scabra is the potential source of terpene with high antioxidant capacity and one of the most valuable species in the trade.ResultsThe results indicated that antioxidant activity of crude methanol extracts and three pure compounds, Friedelin, 3-Hydroxybenzaldehyde and 4-Hydroxybenzaldehyde, from sea cucumber was determined using DPPH, Folin–Cioccalteau reagent. The results indicated the total phenolic contents at 30.52.28 ± 0.21 GAE/g dry weight equivalent and the effective concentration (EC50) value were found to be 33.77 ± 0.24, 14.63 ± 0.01, 14.62 ± 0.01 and 14.78 ± 0.11 mg/ml whole body of Holothuria scabra, Friedelin, 3-Hydroxybenzaldehyde and 4-Hydroxybenzaldehyde, respectively.ConclusionIn conclusion, the methanol extract and pure compounds of whole body parts of sea cucumber showed the highest antioxidant activity with EC50 value of 33.77 ± 0.24, 14.63 ± 0.01, 14.62 ± 0.01 and 14.68 ± 0.11 mg/ml. It also showed the highest total phenolic content at 30.52 ± 0.21 GAE/g dry weight.Graphical abstractHolothuria scabra is the potential source of terpene with high antioxidant capacity. In this study, antioxidants activity of crude methanol extracts and three pure compounds, Friedelin, 3-Hydroxybenzaldehyde and 4-Hydroxybenzaldehyde, from sea cucumber was determined using DPPH, Folin−Cioccalteau reagent. The results indicated the total phenolic contents and the effective concentration (EC50) value