Revealing the mechanistic interactions of profenofos and captan pesticides with serum protein via biophysical and computational investigations

Profenofos (PF) and captan (CT) are among the most utilized organophosphorus insecticides and phthalimide fungicides, respectively. To elucidate the physicochemical and influential toxicokinetic factors, the mechanistic interactions of serum albumin and either PF or CT were carried out in the current study using a series of spectroscopy and computational analyses. Both PF and CT could bind to bovine serum albumin (BSA), a representative serum protein, with moderate binding constants in a range of 103-104 M-1. The bindings of PF and CT did not induce noticeable BSA's structural changes. Both pesticides bound preferentially to the site I pocket of BSA, where the hydrophobic interaction was the main binding mode of PF, and the electrostatic interaction drove the binding of CT. As a result, PF and CT may not only induce direct toxicity by themselves, but also compete with therapeutic drugs and essential substances to sit in the Sudlow site I of serum albumin, which may interfere with the pharmacokinetics and equilibrium of drugs and other substances causing consequent adverse effects.

Promising 8-Aminoquinoline-Based Metal Complexes in the Modulation of SIRT1/3-FOXO3a Axis against Oxidative Damage-Induced Preclinical Neurons

The discovery of novel bioactive molecules as potential multifunctional neuroprotective agents has clinically drawn continual interest due to devastating oxidative damage in the pathogenesis and progression of neurodegenerative diseases. Synthetic 8-aminoquinoline antimalarial drug is an attractive pharmacophore in drug development and chemical modification owing to its wide range of biological activities, yet the underlying molecular mechanisms are not fully elucidated in preclinical models for oxidative damage. Herein, the neuroprotective effects of two 8-aminoquinoline-uracil copper complexes were investigated on the hydrogen peroxide-induced human neuroblastoma SH-SY5Y cells. Both metal complexes markedly restored cell survival, alleviated apoptotic cascades, maintained antioxidant defense, and prevented mitochondrial function by upregulating the sirtuin 1 (SIRT1)/3-FOXO3a signaling pathway. Intriguingly, in silico molecular docking and pharmacokinetic prediction suggested that these synthetic compounds acted as SIRT1 activators with potential drug-like properties, wherein the uracil ligands (5-iodoracil and 5-nitrouracil) were essential for effective binding interactions with the target protein SIRT1. Taken together, the synthetic 8-aminoquinoline-based metal complexes are promising brain-targeting drugs for attenuating neurodegenerative diseases.

Aminochalcones Attenuate Neuronal Cell Death under Oxidative Damage via Sirtuin 1 Activity

Encouraged by the lack of effective treatments and the dramatic growth in the global prevalence of neurodegenerative diseases along with various pharmacological properties of chalcone pharmacophores, this study focused on the development of aminochalcone-based compounds, organic molecules characterized by a chalcone backbone (consisting of two aromatic rings connected by a three-carbon α,β-unsaturated carbonyl system) with an amino group attached to one of the aromatic rings, as potential neuroprotective agents. Thus, the aminochalcone-based compounds in this study were designed by bearing a -OCH3 moiety at different positions on the ring and synthesized by the Claisen-Schmidt condensation. The compounds exhibited strong neuroprotective effects against hydrogen peroxide-induced neuronal death in the human neuroblastoma (SH-SY5Y) cell line (i.e., by improving cell survival, reducing reactive oxygen species production, maintaining mitochondrial function, and preventing cell membrane damage). The aminochalcone-based compounds showed mild toxicity toward a normal embryonic lung cell line (MRC-5) and a human neuroblastoma cell line, and were predicted to have preferable pharmacokinetic profiles with potential for oral administration. Molecular docking simulation indicated that the studied aminochalcones may act as competitive activators of the well-known protective protein, SIRT1, and provided beneficial knowledge regarding the essential key chemical moieties and interacting amino acid residues. Collectively, this work provides a series of four promising candidate agents that could be developed for neuroprotection.

One-step impedimetric NT-proBNP aptasensor targeting cardiac insufficiency in artificial saliva

Currently, sensitive and accurate approaches for diagnosis, rapid assessment, and cardiac biomarker monitoring in patients with heart failure are needed. In this context, the advantages of aptamers over traditional antibodies have been employed to fabricate a single-step impedimetric N-terminal pro b-type natriuretic peptide (NT-proBNP)-modified gold microelectrode array. The development of an electrochemical aptasensing platform was based on the coimmobilization of alkanethiol self-assembled monolayers and amine-terminated aptamer that specifically recognized cardiac NT-proBNP protein resulting in charge electron transfer. Electroimpedimetric signals of the sensor were observed to be linear to the NT-proBNP concentrations in the range of 5.0 × 10^-3 to 1.0 pg mL^-1 (R² = 0.9624), while achieving a low detection limit of 5.0 × 10^-3 pg mL^-1. Clinically relevant detection levels for NT-proBNP were achieved in a simple, rapid, and label-free measurement using artificial saliva, which was highlighted to be specific, regenerative, and selective over potential interferers occurring during the processes of cardiac insufficiency, Therefore, the novel NT-proBNP aptasensor is a promising point-of-care tool exhibiting safe, non-invasive, affordable, and non-prescription home use accessible to overcome the limitations associated with conventional ELISA and previous aptasensing.

Neuroprotective Properties of Bis-Sulfonamide Derivatives Against 6-OHDA-Induced Parkinson's Model via Sirtuin 1 Activity and in silico Pharmacokinetic Properties

Parkinson's disease (PD) is considered one of the health problems in the aging society. Due to the limitations of currently available drugs in preventing disease progression, the discovery of novel neuroprotective agents has been challenged. Sulfonamide and its derivatives were reported for several biological activities. Herein, a series of 17 bis-sulfonamide derivatives were initially tested for their neuroprotective potential and cytotoxicity against the 6-hydroxydopamine (6-OHDA)-induced neuronal death in SH-SY5Y cells. Subsequently, six compounds (i.e., 2, 4, 11, 14, 15, and 17) were selected for investigations on underlying mechanisms. The data demonstrated that the pretreatment of selected compounds (5 μM) can significantly restore the level of cell viability, protect against mitochondrial membrane dysfunction, decrease the activity of lactate dehydrogenase (LDH), decrease the intracellular oxidative stress, and enhance the activity of NAD-dependent deacetylase sirtuin-1 (SIRT1). Molecular docking was also performed to support that these compounds could act as SIRT1 activators. In addition, in silico pharmacokinetic and toxicity profile prediction was also conducted for guiding the potential development. Thus, the six neuroprotective bis-sulfonamides were highlighted as potential agents to be further developed for PD management.

Boiling, Blanching, and Stir-Frying Markedly Reduce Pesticide Residues in Vegetables

Nowadays, a lot of produce (fruits and vegetables) sold in many countries are contaminated with pesticide residues, which cause severe effects on consumer health, such as cancer and neurological disorders. Therefore, this study aims to determine whether cooking processes can reduce the pesticide residues in commonly consumed vegetables (Chinese kale and yard long beans) in Thailand. For cooking experiments, the two vegetables were cooked using three different processes: boiling, blanching, and stir-frying. After the treatments, all cooked and control samples were subjected to extraction and GC-MS/MS analysis for 88 pesticides. The results demonstrated that pesticide residues were reduced by 18–71% after boiling, 36–100% after blanching, and 25–60% after stir-frying for Chinese kale. For yard long beans, pesticide residues were reduced by 38–100% after boiling, 27–28% after blanching, and 35–63% after stir-frying. Therefore, cooking vegetables are proven to protect consumers from ingesting pesticide residues.

Modulatory Effects of Alpha-Mangostin Mediated by SIRT1/3-FOXO3a Pathway in Oxidative Stress-Induced Neuronal Cells

Background

alpha-Mangostin, a polyphenolic xanthone, is primarily found in the pericarp of mangosteen throughout Southeast Asia and is considered as the “Queen of Fruit” in Thailand. Nonetheless, it is not clarified how alpha-mangostin protects neuronal cells against oxidative stress.

Objective

In this study, molecular mechanisms underlying the neuroprotective effect of alpha-mangostin in defending hydrogen peroxide (H2O2)-induced neurotoxicity was explored.

Methods

cytotoxicity, reactive oxygen species (ROS) generation, apoptotic cascades, and protein expression profiles were performed incorporation of molecular docking.

Results

Human SH-SY5Y cells were pretreated with 1 μM alpha-mangostin for 3 h prior to exposure to 400 μM H2O2. alpha-Mangostin significantly inhibited oxidative stress-induced cell death in neuronal cells by reducing BAX protein, decreasing caspase-3/7 activation, and increasing anti-apoptotic BCL-2 protein. Collectively, alpha-mangostin was demonstrated to be a prominent ROS suppressor which reversed the reduction of antioxidant enzymes (CAT and SOD2). Surprisingly, alpha-mangostin significantly promoted the expression of the sirtuin family and the FOXO3a transcription factor exerting beneficial effects on cell survival and longevity. A molecular docking study predicted that alpha-mangostin is directly bound to the active site of SIRT1.

Conclusion

Findings from this study suggest that alpha-mangostin potentially serves as a promising therapeutic compound against oxidative stress by activation of the SIRT1/3-FOXO3a pathway comparable to the effect of memantine, an anti-AD drug used for the treatment of moderate to severe dementia.

Mechanisms and Neuroprotective Activities of Stigmasterol Against Oxidative Stress-Induced Neuronal Cell Death via Sirtuin Family

Background: Accumulating studies have confirmed that oxidative stress leads to the death of neuronal cells and is associated with the progression of neurodegenerative diseases, including Alzheimer's disease (AD). Despite the compelling evidence, there is a drawback to the use of the antioxidant approach for AD treatment, partly due to limited blood-brain barrier (BBB) permeability. Phytosterol is known to exhibit BBB penetration and exerts various bioactivities such as antioxidant and anticancer effects, and displays a potential treatment for dyslipidemia, cardiovascular disease, and dementia. Objective: In this study, the protective effects of stigmasterol, a phytosterol compound, on cell death induced by hydrogen peroxide (H2O2) were examined in vitro using human neuronal cells (SH-SY5Y cells). Methods: MTT assay, reactive oxygen species measurement, mitochondrial membrane potential assay, apoptotic cell measurement, and protein expression profiles were performed to determine the neuroprotective properties of stigmasterol. Results: H2O2 exposure significantly increased the levels of reactive oxygen species (ROS) within the cells thereby inducing apoptosis. On the contrary, pretreatment with stigmasterol maintained ROS levels inside the cells and prevented oxidative stress-induced cell death. It was found that pre-incubation with stigmasterol also facilitated the upregulation of forkhead box O (FoxO) 3a, catalase, and anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) in the neurons. In addition, the expression levels of sirtuin 1 (SIRT1) were also increased while acetylated lysine levels were decreased, indicating that SIRT1 activity was stimulated by stigmasterol, and the result was comparable with the known SIRT1 activator, resveratrol. Conclusion: Taken together, these results suggest that stigmasterol could be potentially useful to alleviate neurodegeneration induced by oxidative stress.

Sesamin and sesamol attenuate H2O2-induced oxidative stress on human neuronal cells via the SIRT1-SIRT3-FOXO3a signaling pathway

Background: An imbalance of free radicals and antioxidant defense systems in physiological processes can result in protein/DNA damage, inflammation, and cellular apoptosis leading to neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Sesamin and sesamol, compounds derived from sesame seeds and oil, have been reported to exert various pharmacological effects, especially antioxidant activity. However, their molecular mechanisms against the oxidative stress induced by exogenous hydrogen peroxide (H₂O₂) remain to be elucidated. Aim: In this study, neuroprotective effects of sesamin and sesamol on H₂O₂-induced human neuroblastoma (SH-SY5Y) cell death and possible signaling pathways in the cells were explored. Methods: MTT assay and flow cytometry were conducted to determine cell viability and apoptotic profiles of neuronal cells treated with sesamin and sesamol. Carboxy-DCFDA assay was used to measure reactive oxygen species (ROS). Moreover, Western blot analysis was performed to investigate protein profiles associated with neuroprotection. Results: Pretreatment of the cells with 1 µM of sesamin and sesamol remarkably reduced the SH-SY5Y cell death induced by 400 µM H₂O₂ as well as the intracellular ROS production. Moreover, the molecular mechanisms underlying neuroprotection of the compounds were associated with activating SIRT1-SIRT3-FOXO3a expression, inhibiting BAX (proapoptotic protein), and upregulating BCL-2 (anti-apoptotic protein). Conclusion: The findings suggest that sesamin and sesamol are compounds that potentially protect neuronal cells against oxidative stress similar to that of the resveratrol, the reference compound. These antioxidants are thus of interest for further investigation in in vivo models of neuroprotection.

Pesticide Aptasensors-State of the Art and Perspectives

Contamination by pesticides in the food chain and the environment is a worldwide problem that needs to be actively monitored to ensure safety. Unfortunately, standard pesticide analysis based on mass spectrometry takes a lot of time, money and effort. Thus, simple, reliable, cost-effective and field applicable methods for pesticide detection have been actively developed. One of the most promising technologies is an aptamer-based biosensor or so-called aptasensor. It utilizes aptamers, short single-stranded DNAs or RNAs, as pesticide recognition elements to integrate with various innovative biosensing technologies for specific and sensitive detection of pesticide residues. Several platforms for aptasensors have been dynamically established, such as colorimetry, fluorometry, electrochemistry, electrochemiluminescence (ECL) and so forth. Each platform has both advantages and disadvantages depending on the purpose of use and readiness of technology. For example, colorimetric-based aptasensors are more affordable than others because of the simplicity of fabrication and resource requirements. Electrochemical-based aptasensors have mainly shown better sensitivity than others with exceedingly low detection limits. This paper critically reviews the progression of pesticide aptasensors throughout the development process, including the selection, characterization and modification of aptamers, the conceptual frameworks of integrating aptamers and biosensors, the ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free and deliverable to end users) criteria of different platforms and the future outlook.

Alterations in Mitochondrial Dynamic-related Genes in the Peripheral Blood of Alzheimer's Disease Patients

BACKGROUND

Mitochondrial dysfunction is a pathological feature that manifests early in the brains of patients with Alzheimer's Disease (AD). The disruption of mitochondrial dynamics contributes to mitochondrial morphological and functional impairments. Our previous study demonstrated that the expression of genes involved in amyloid beta generation was altered in the peripheral blood of AD patients.

OBJECTIVE

The aim of this study was to further investigate the relative levels of mitochondrial genes involved in mitochondrial dynamics, including mitochondrial fission and fusion, and mitophagy in peripheral blood samples from patients with AD compared to healthy controls.

METHODS

The mRNA levels were analyzed by real-time polymerase chain reaction. Gene expression profiles were assessed in relation to cognitive performance.

RESULTS

Significant changes were observed in the mRNA expression levels of fission-related genes; Fission1 (FIS1) levels in AD subjects were significantly higher than those in healthy controls, whereas Dynamin- related protein 1 (DRP1) expression was significantly lower in AD subjects. The levels of the mitophagy-related genes, PTEN-induced kinase 1 (PINK1) and microtubule-associated protein 1 light chain 3 (LC3), were significantly increased in AD subjects and elderly controls compared to healthy young controls. The mRNA levels of Parkin (PARK2) were significantly decreased in AD. Correlations were found between the expression levels of FIS1, DRP1 and PARK2 and cognitive performance scores.

CONCLUSION

Alterations in mitochondrial dynamics in the blood may reflect impairments in mitochondrial functions in the central and peripheral tissues of AD patients. Mitochondrial fission, together with mitophagy gene profiles, might be potential considerations for the future development of blood-based biomarkers for AD.

Alterations in the Expression of Amyloid Precursor Protein Cleaving Enzymes mRNA in Alzheimer Peripheral Blood

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia in elderly populations. Changes in the expression of the Amyloid Precursor Protein (APP)-cleaving enzymes directly affect the formation of Amyloid Beta (Aβ) plaques, a neuropathological hallmark of AD.

OBJECTIVE

We used peripheral blood from AD patients to investigate the expression of genes related to APP-processing [(β-site APP-cleaving enzyme 1 (BACE1), presenilin1 (PSEN1), and a disintegrin and metalloproteinase family 10 (ADAM10) and 17 (ADAM17)] and the epigenetic genes sirtuin (SIRT)1-3, which regulate Aβ production.

METHOD

Real-time polymerase chain reactions were performed to determine the specific mRNA levels in plasma. The mRNA levels in AD patients were compared to those in healthy persons and assessed in relation to the subjects' cognitive performance.

RESULTS

BACE1 mRNA level in AD subjects was significantly higher than those of healthy controls, whereas ADAM10 level was significantly lower in the AD subjects. The SIRT1 level was significantly decreased, while that of SIRT2 was increased in AD subjects and elderly controls compared to levels in healthy young control. In addition, correlations were found between the expression levels of BACE1, ADAM10 and SIRT1 and cognitive performance scores. Total Aβ (Aβ40+Aβ42) levels and the Aβ40/Aβ42 ratio were significantly increased in the AD subjects, whereas decrease in plasma Aβ42 was found in AD subjects. There was a negative correlation between Aβ40 or total Aβ and Thai Mental State Examination (TMSE) while there was no correlation between Aβ40/Aβ42 ratio or Aβ42 and TMSE.

CONCLUSION

The present findings provide evidence and support for the potential roles of these enzymes that drive Aβ synthesis and for epigenetic regulation in AD progression and development, which can possibly be considered peripheral markers of AD.

Butein, isoliquiritigenin, and scopoletin attenuate neurodegeneration via antioxidant enzymes and SIRT1/ADAM10 signaling pathway

Neuronal cell death is a key feature of neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. Plant polyphenols, namely butein, isoliquiritigenin, and scopoletin, have been shown to exhibit various biological activities including anti-inflammatory, antimicrobial, and antioxidant activities. Herein, butein, isoliquiritigenin, and scopoletin were explored for their neuroprotective properties against oxidative stress-induced human dopaminergic SH-SY5Y cell death. The cells exposed to hydrogen peroxide (H₂O₂) revealed a reduction in cell viability and increases in apoptosis and levels of reactive oxygen species (ROS). Interestingly, pretreatment of SH-SY5Y cells with 5 μM of butein, isoliquiritigenin, or scopoletin protected against the cell death induced by H₂O₂, and decreased the levels of apoptotic cells and ROS. In addition, the levels of SIRT1, FoxO3a, ADAM10, BCL-2, and antioxidant enzymes (catalase and SOD2) were maintained in the cells pretreated with butein, isoliquiritigenin, or scopoletin before H₂O₂ treatment compared to cells without pretreatment and the reference (resveratrol). Molecular docking analysis revealed that the interactions between the activator-binding sites of SIRT1 and the phenolic compounds were similar to those of resveratrol. Taken together, the data suggest that these polyphenolic compounds could be potential candidates for prevention and/or treatment of neurodegeneration.

Neuronal cells exposed to H₂O₂ may undergo increase ROS, reduction in cell viability and cell death. Butein, isoliquiritigenin, and scopoletin ameliorated H₂O₂-induced neurotoxicity by reducing ROS, balancing antioxidants and activating SIRT1-FoxO3a-ADAM10 pathway.

Insight into the Molecular Interaction of Cloxyquin (5-chloro-8-hydroxyquinoline) with Bovine Serum Albumin: Biophysical Analysis and Computational Simulation

Cloxyquin is a potential therapeutic compound possessing various bioactivities, especially antibacterial, antifungal, cardioprotective, and pain relief activities. Herein, the interaction mechanism between cloxyquin and bovine serum albumin (BSA) has been elucidated in order to fulfill its pharmacokinetic and pharmacodynamic gaps essential for further development as a therapeutic drug. Multi-spectroscopic and biophysical model analysis suggested that cloxyquin interacts with BSA via a static process by ground-state complex formation. Its binding behavior emerged as a biphasic fashion with a moderate binding constant at the level of 104 M-1. Thermodynamic analysis and molecular docking simulation concurrently revealed that hydrophobic interaction is a major driving force for BSA-cloxyquin complexation. Binding of cloxyquin tends to slightly enlarge the monomeric size of BSA without a significant increase of aggregate fraction. Cloxyquin preferentially binds into the fatty acid binding site 5 (FA5) of the BSA via hydrophobic interaction amongst its quinoline scaffold and Phe550, Leu531, and Leu574 residues of BSA. The quinoline ring and hydroxyl moiety of cloxyquin also form the π-π interaction and the hydrogen bond with Phe506. Our data indicate a potential function of serum albumin as a carrier of cloxyquin in blood circulation.

Multidisciplinary approaches for targeting the secretase protein family as a therapeutic route for Alzheimer's disease

The continual increase of the aging population worldwide renders Alzheimer's disease (AD) a global prime concern. Several attempts have been focused on understanding the intricate complexity of the disease's development along with the on- andgoing search for novel therapeutic strategies. Incapability of existing AD drugs to effectively modulate the pathogenesis or to delay the progression of the disease leads to a shift in the paradigm of AD drug discovery. Efforts aimed at identifying AD drugs have mostly focused on the development of disease-modifying agents in which effects are believed to be long lasting. Of particular note, the secretase enzymes, a group of proteases responsible for the metabolism of the β-amyloid precursor protein (βAPP) and β-amyloid (Aβ) peptides production, have been underlined for their promising therapeutic potential. This review article attempts to comprehensively cover aspects related to the identification and use of drugs targeting the secretase enzymes. Particularly, the roles of secretases in the pathogenesis of AD and their therapeutic modulation are provided herein. Moreover, an overview of the drug development process and the contribution of computational (in silico) approaches for facilitating successful drug discovery are also highlighted along with examples of relevant computational works. Promising chemical scaffolds, inhibitors, and modulators against each class of secretases are also summarized herein. Additionally, multitarget secretase modulators are also taken into consideration in light of the current growing interest in the polypharmacology of complex diseases. Finally, challenging issues and future outlook relevant to the discovery of drugs targeting secretases are also discussed.

Food safety in Thailand. 3: Pesticide residues detected in mangosteen (Garcinia mangostana L.), queen of fruits

BACKGROUND

For developing countries like Thailand, regulation of pesticide usage exists, but it is not fully enforced. Therefore, pesticide residues in vegetables and fruits have not been well monitored. This study aimed to determine the pesticide residues in mangosteen fruits sold in Thailand. The mangosteen samples (n = 111) were purchased and the contents of 28 pesticides were analysed by GC-MS/MS method.

RESULTS

Of the pesticides tested, eight were found in 100% of the mangosteen samples. However, in 97% of these samples, either chlorothalonil, chlorpyrifos, diazinon, dimethoate, metalaxyl or profenofos was detected exceeding their maximum residue limits (MRLs), representing a 97% rate of pesticide detection above the MRL. This rate is much higher than those found in other fruits sold in developed countries. However, this conclusion excludes the fresh Thai mangosteens grown for export, as these are generally cultivated and harvested to GAP standards. Since the edible part of the mangosteen is the pulp, washing the fruits with running water can reduce the risk of pesticide residues contaminating the pulp which would be eaten by the consumer.

CONCLUSION

The findings strongly suggest that routine monitoring of pesticide residues in fruits and vegetables is required to reduce the health risks associated with consuming contaminated food. © 2016 Society of Chemical Industry.

Food safety in Thailand 4: comparison of pesticide residues found in three commonly consumed vegetables purchased from local markets and supermarkets in Thailand

Background

The wide use of pesticides raises concerns on the health risks associated with pesticide exposure. For developing countries, like Thailand, pesticide monitoring program (in vegetables and fruits) and also the maximum residue limits (MRL) regulation have not been entirely implemented. The MRL is a product limit, not a safety limit. The MRL is the maximum concentration of a pesticide residue (expressed as mg/kg) recommended by the Codex Alimentarius Commission to be legally permitted in or on food commodities and animal feeds (Codex Alimentarius Commission, 2015; European Commission, 2015). MRLs are based on supervised residue trial data where the pesticide has been applied in accordance with GAP (Good Agricultural Practice). This study aims at providing comparison data on pesticide residues found in three commonly consumed vegetables (Chinese kale, pakchoi and morning glory) purchased from some local markets and supermarkets in Thailand.

Methods

These vegetables were randomly bought from local markets and supermarkets. Then they were analyzed for the content of 28 pesticides by using GC-MS/MS.

Results

Types of pesticides detected in the samples either from local markets or supermarkets were similar. The incidence of detected pesticides was 100% (local markets) and 99% (supermarkets) for the Chinese kale; 98% (local markets) and 100% (supermarkets) for the pakchoi; and 99% (local markets) and 97% (supermarkets) for the morning glory samples. The pesticides were detected exceeding their MRL at a rate of 48% (local markets) and 35% (supermarkets) for the Chinese kale; 71% (local markets) and 55% (supermarkets) for the pakchoi, and 42% (local markets) and 49% (supermarkets) for the morning glory.

Discussion

These rates are much higher than those seen in developed countries. It should be noted that these findings were assessed on basis of using criteria (such as MRL) obtained from developed countries. Our findings were also confined to these vegetables sold in a few central provinces of Thailand and did not reflect for the whole country as sample sizes were small. Risk assessment due to consuming these pesticide contaminated vegetables, still remains to be evaluated. However, remarkably high incidence rates of detected pesticides give warning to the Thai authorities to implement proper regulations on pesticide monitoring program. Similar incidence of pesticide contamination found in the vegetables bought from local markets and supermarkets raises question regarding the quality of organic vegetables domestically sold in Thailand. This conclusion excludes Thai export quality vegetables and fruits routinely monitored for pesticide contamination before exporting.

Antimalarial and antimicrobial activities of 8-Aminoquinoline-Uracils metal complexes

8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents.

Food safety in Thailand 2: Pesticide residues found in Chinese kale (Brassica oleracea), a commonly consumed vegetable in Asian countries

There is increasing public concern over human health risks associated with extensive use of pesticides in agriculture. Regulation of pesticide maximum residue limits (MRLs) in food commodities is established in many developed countries. For Thailand, this regulation exists in law but is not fully enforced. Therefore, pesticide residues in vegetables and fruits have not been well monitored. This study investigated the pesticide residues in Chinese kale, a commonly eaten vegetable among Asians. The Chinese kale samples (N = 117) were purchased from markets in Nakhon Pathom Province, Thailand, and analyzed for the content of 28 pesticides. Analysis was performed by the multiresidual extraction followed by GC-MS/MS. Of pesticides investigated, 12 pesticides were detected in 85% of the Chinese kale samples. Although carbaryl, deltamethrin, diazinon, fenvalerate and malathion were found in some samples, their levels were lower than their MRLs. However, in 34 samples tested, either carbofuran, chlorpyrifos, chlorothalonil, cypermethrin, dimethoate, metalaxyl or profenofos was detected exceeding their MRLs. This represents a 29% rate of pesticide detection above the MRL; a rate much higher than in developed countries. Washing vegetables under running water significantly reduced (p < 0.05) profenofos residues by 55%. The running water method did not significantly decrease cypermethrin residues in the samples but washing with vinegar did. Our research suggests that routine monitoring of pesticide residues is necessary to reduce the public health risks associated with eating contaminated vegetables. Washing vegetables before consumption is advisable as this helps to reduce the level of pesticide residues in our daily intake.

Cytochrome P450 enzyme mediated herbal drug interactions (Part 2)

To date, a number of significant herbal drug interactions have their origins in the alteration of cytochrome P450 (CYP) activity by various phytochemicals. Among the most noteworthy are those involving St. John's wort and drugs metabolized by human CYP3A4 enzyme. This review article is the continued work from our previous article (Part 1) published in this journal (Wanwimolruk and Prachayasittikul, 2014[ref:133]). This article extends the scope of the review to six more herbs and updates information on herbal drug interactions. These include black cohosh, ginseng, grape seed extract, green tea, kava, saw palmetto and some important Chinese medicines are also presented. Even though there have been many studies to determine the effects of herbs and herbal medicines on the activity of CYP, most of them were in vitro and in animal studies. Therefore, the studies are limited in predicting the clinical relevance of herbal drug interactions. It appeared that the majority of the herbal medicines have no clear effects on most of the CYPs examined. For example, the existing clinical trial data imply that black cohosh, ginseng and saw palmetto are unlikely to affect the pharmacokinetics of conventional drugs metabolized by human CYPs. For grape seed extract and green tea, adverse herbal drug interactions are unlikely when they are concomitantly taken with prescription drugs that are CYP substrates. Although there were few clinical studies on potential CYP-mediated interactions produced by kava, present data suggest that kava supplements have the ability to inhibit CYP1A2 and CYP2E1 significantly. Therefore, caution should be taken when patients take kava with CYP1A2 or CYP2E1 substrate drugs as it may enhance their therapeutic and adverse effects. Despite the long use of traditional Chinese herbal medicines, little is known about the potential drug interactions with these herbs. Many popularly used Chinese medicines have been shown in vitro to significantly change the activity of human CYP. However, with little confirming evidence from clinical studies, precaution should be exercised when patients are taking Chinese herbal medicines concomitantly with drugs that are CYP substrates. Currently there is sufficient evidence to indicate that herbal drug interactions can occur and may lead to serious clinical consequence. Further clinical trial research should be conducted to verify these herbal drug interactions. Education on herbal drug interactions and communication with patients on their use of herbal products is also important.