Individuals respond differently to drugs and sometimes the effects are unpredictable. Differences in DNA that alter the expression or function of proteins targeted by drugs can contribute significantly to the variation in the individuals responses. The use of pharmacogenomics is to identify genetic polymorphisms that predispose patients to adverse drug effects that, although they may occur in only a small subset of the people treated with a new medication, are sufficiently toxic to jeopardise further development of the drug for all patients. Given the potential value of knowing all the possible factors that influence the effects of new agents, it is likely that pharmacogenomics will have an increasingly important role in drug discovery and development. This article briefly reviews concepts that underlie the emerging fields of pharmacogenetics and pharmacogenomics, with an emphasis on the pharmacogenetics of drug metabolism. Although only a few examples will be provided to illustrate concepts and to demonstrate the potential contribution of pharmacogenetics to medical practice, it is now clear that virtually every pathway of drug metabolism will eventually be found to have genetic variation.
The production of ethanol, from glucose in batch and fed batch culture, was investigated. In the fed batch culture, the glucose feeding was added into the culture at 16th hour of fermentation. The effects of different glucose concentration feeding rates on ethanol fermentation were investigated for fed batch culture. The 2gL-1hr-1 glucose concentration feeding rate was found to give higher ethanol yield (2.47 g ethanol g glucose-1), with respect to substrate consumed as compared to 8 gL-1hr-1 (0.23 g ethanol g glucose-1) and 4 gL-1hr-1 (0.20 g ethanol g glucose-1). The ethanol yield with respect to substrate consumed obtained in batch culture was 0.81 g ethanol g glucose-1. The fed batch culture at 2 gL-1hr-1 glucose concentration feeding rate was proven to be a better fermentation system than the batch culture. The specific growth rate, specific glucose consumption rate and specific ethanol production rate for the fed batch fermentation, at 2 gL-1hr-1 glucose concentration feeding rate, were 0.065 hr-1, 1.20 hr-1 and 0.0009 hr-1, respectively.
Argininosuccinate lyase (ASL) deficiency impairs the function of the urea cycle that detoxifies blood ammonia in the body. Mutation that occurs in the ASL gene is the cause of occurrence of ASL deficiency (ASLD). This deficiency causes hyperammonemia, hepatopathy and neurodevelopmental delay in patients. In this study, the clinical characteristics and molecular analysis of 10 ASLD patients were presented. 8 patients were associated with severe neonatal onset, while the other 2 were associated with late onset. Molecular analysis of ASL gene identified four new missense variants, which were c.778C>T, p.(Leu260Arg), c.1340G>C, p.(Ser447Thr), c.436C>G, p.(Arg146Gly) and c.595C>G, p.(Leu199Val) and four reported missense variants, which were c.638G>A, p.(Arg213Gln); c.556C>T, p.(Arg186Trp), c.578G>A, p.(Arg193Gln) and c.436C>G, p.(Arg146Trp). In silico servers predicted all new and reported variants as disease-causing. Structural examination exhibited that all pathogenic variants affected the stability of the tetrameric ASL structure by disturbing the bonding pattern with the neighboring residues.
Conclusion: This study revealed the genetic heterogeneity among Malaysian ASL patients. This study has also expanded the mutational spectrum of the ASL.
Ethanol fermentations by Candida shehatae TISTR 5843 at low (20 g/L) and high (80 g/L) sugar concentrations with various glucose to xylose ratios were investigated. Glucose was a preferred substrate as it was consumed first at a faster consumption rate. The type of sugar and ratio between glucose and xylose did not have an effect on ethanol produced. The average ethanol concentrations were 7.99 g/L when using 20 g/L sugar and 27.82 g/L when using 80 g/L sugar. Small amounts of xylitol and glycerol as by-products were presented when using 20 g/L sugar. Xylitol appeared to be the main by-product at high xylose concentration with elevated concentrations as xylose is increased. When using rice straw hydrolysate containing 34.75 g/L glucose and 21.29 g/L xylose, 19.37 g/L ethanol was produced with the ethanol yield and ethanol productivity at 0.49 g/g and 0.20 g/L.h, respectively. However, xylose was not completely consumed after fermentation was complete.
This study examines the biological efficacy of four mosquito mat vaporizers each containing different active ingredients: prallethrin with PBO, dimefluthrin, prallethrin, and d-allethrin. The glass chamber assay was used to evaluate their efficacy on Aedes albopictus (Skuse) (Diptera: Culicidae) from nine districts in Selangor, Malaysia. Aedes albopictus exhibited different knockdown rates, with 50% knockdown times, KT50, varying from 1.19 to 2.00 min, 1.22 to 2.20 min, 1.39 to 5.85 min, and 1.39 to 1.92 min for prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. In general, all populations of Ae. albopictus were completely knocked down after exposure to all active ingredients except Hulu Selangor population, which showed 96.00% knockdown against d-allethrin. On the contrary, mortality rates were observed from 84.00-100.00%, 84.00-100.00%, 90.67-100.00% and 90.67-100.00% in populations tested with prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. Moreover, significant correlations between mortality rates of prallethrin with PBO vs dimefluthrin (r = 0.836, P = 0.003), prallethrin with PBO vs prallethrin (r = 0.760, P = 0.011), and prallethrin vs d-allethrin (r = 0.694, P = 0.026) were also observed, suggesting cross-resistance among pyrethroids. d-allethrin was found to be high in insecticidal activity, followed by prallethrin, prallethrin with PBO, and dimefluthrin. In consistent with mortality due to insecticide exposure, elevated levels of enzyme activities were also demonstrated in Sabak Bernam, Hulu Selangor, Gombak, Petaling, Hulu Langat and Klang populations.
Nanoparticles (NPs) have wide spectrum applications in the areas of industry and biomedicine. However, concerns about their toxic and negative impacts on the environments as well as human health have been raised. Cytochrome P450s (CYPs) are involved in endogenous and exogenous metabolism. Modulations of CYP can adversely damage drug metabolism, detoxification of xenobiotics and animal physiology functions. This article focused on NPs-CYP interactions for humans and animals available in the literature. It was found that different NPs process specific inhibitory potencies against CYPs involved in drug metabolism. Moreover, NPs were able to modify the expression of CYPs genes or protein in humans and other animals, which highlighted their detoxification functions. Nonetheless, changes of CYPs responsible for hormone synthesis and metabolism resulted in endocrine disturbances. Hence, there is a need to screen newly developed NPs to evaluate their interactions with CYPs. The future studies should further strategize the in vitro approaches to reveal the molecular mechanisms behind interactions by taking full considerations of the interference of co-factors, buffers, substrates and metabolites with NPs. Moreover, in vivo studies should compare the influences of NPs via different administration routes and different duration of treatments to reveal the physiological significance.
1. Toxicity evaluations of DDT, lindane, abate and carbaryl were carried out in the larvae of two wild Aedes aegypti strains from Kuala Lumpur and Klang. The Kuala Lumpur strain was more susceptible to the insecticides than the Klang strain. 2. The lethal toxicity time was also determined. The insecticides were found to take a longer time to exert their effect in the Klang strain as compared to the Kuala Lumpur strain. 3. Carboxylesterase activity was determined to be higher in the Kuala Lumpur strain, but glutathione transferase activities were higher in the Klang strain.
This study aimed to identify the bioactive compounds of the ethyl acetate extract of Aspergillus niger SH2-EGY using GC-MS and to evaluate their protective role against aflatoxin B1 (AFB1)-induced oxidative stress, genotoxicity and cytotoxicity in rats. Six groups of male Sprague-Dawley rats were treated orally for 4 weeks included the control group, AFB1-treated group (80 μg/kg b.w); fungal extract (FE)-treated groups at low (140) or high dose (280) mg/kg b.w and the groups treated with AFB1 plus FE at the two tested doses. The GC-MS analysis identified 26 compounds. The major compounds found were 1,2,3,4,6-Penta-trimethylsilyl Glucopyranose, Fmoc-L-3-(2-Naphthyl)-alanine, D-(-)-Fructopyranose, pentakis (trimethylsilyl) ether, bis (2-ethylhexyl) phthalate, trimethylsilyl ether-glucitol, and octadecanamide, N-(2- methylpropyl)-N-nitroso. The in vivo results showed that AFB1 significantly increased serum ALT, AST, creatinine, uric acid, urea, cholesterol, triglycerides, LDL, carcinoembryonic antigen, alpha-fetoprotein, interleukin-6, Malondialdehyde, nitric oxide, Bax, caspase-3 and P53 mRNA expression, chromosomal aberrations and DNA fragmentation. It decreased serum TP, albumin, HDL, Bcl-2 mRNA expression, hepatic and renal TAC, SOD and GPx content and induced histological changes in the liver and kidney. FE prevented these disturbances in a dosage-dependent manner. It could be concluded that A. niger SH2-EGY extract is safe a promising agent for pharmaceutical and food industries.
Many insect species display daily variation of sensitivity to insecticides when they are exposed to the same concentration at different times during the day. To date, this has not been investigated in bed bugs. To address this, we explored circadian rhythms in insecticide susceptibility, xenobiotic metabolizing (XM) gene expressions, and metabolic detoxification in the common bed bug, Cimex lectularius. An insecticide susceptible Monheim strain of C. lectularius was most tolerant of deltamethrin during the late photophase at ZT9 (i.e. nine hours after light is present in the light-dark cycle (LD) cycle) and similarly repeated at CT9 (i.e. nine hours into the subjective day in constant darkness (DD)) suggesting endogenous circadian involvement in susceptibility to deltamethrin. No diel rhythm was observed against imidacloprid insecticide despite significant daily susceptibility in both LD and DD conditions. Rhythmic expressions of metabolic detoxification genes, GSTs1 and CYP397A1 displayed similar expression patterns with total GST and P450 enzyme activities in LD and DD conditions, respectively. The oscillation of mRNA levels of GSTs1 and CYP397A1 was found consistent with peak phases of deltamethrin susceptibility in C. lectularius. This study demonstrates that circadian patterns of metabolic detoxification gene expression occur within C. lectularius. As a consequence, insecticide efficacy can vary dramatically throughout a 24 hour period.
A multiplex RT-qPCR was developed to examine CYP1A2, CYP2D6, and CYP3A4 induction properties of compounds from food and herbal sources. The induction of drug metabolizing enzymes is an important pharmacokinetic interaction with unique features in comparison with inhibition of metabolizing enzymes. Cytochrome induction can lead to serious drug-drug or drug-food interactions, especially if the coadministered drug plasma level is critical as it can reduce therapeutic effects and cause complications. Using this optimized multiplex RT-qPCR, cytochrome induction properties of andrographolide, curcumin, lycopene, bergamottin, and resveratrol were determined. Andrographolide, curcumin, and lycopene produced no significant induction effects on CYP1A2, CYP2D6, and CYP3A4. However, bergamottin appeared to be a significant in vitro CYP1A2 inducer starting from 5 to 50 μmol/L with induction ranging from 60 to 100-fold changes. On the other hand, resveratrol is a weak in vitro CYP1A2 inducer. Examining the cytochrome induction properties of food and herbal compounds help complement CYP inhibition studies and provide labeling and safety caution for such products.
Detoxifying enzymes are present in most epithelial cells of the human gastrointestinal tract where they protect against xenobiotics which may cause cancer. Induction of examples such as glutathione S-transferase (GST) and its thiol conjugate, glutathione (GSH) as well as NAD(P)H: quinoneoxidoreductase (NQO1) facilitate the excretion of carcinogens and thus preventing colon carcinogenesis. Pterostilbene, an analogue of resveratrol, has demonstrated numerous pharmacological activities linked with chemoprevention. This study was conducted to investigate the potential of pterostilbene as a chemopreventive agent using the HT-29 colon cancer cell line to study the modulation of GST and NQO1 activities as well as the GSH level. Initially, our group, established the optimum dose of 24 hours pterostilbene treatment using MTT assays. Then, effects of pterostilbene (0-50 μM) on GST and NQO1 activity and GSH levels were determined using GST, NQO1 and Ellman assays, respectively. MTT assay of pterostilbene (0-100 μM) showed no cytotoxicity toward the HT-29 cell line. Treatment increased GST activity in the cell line significantly (p<0.05) at 12.5 and 25.0 μM. In addition, treatment at 50 μM increased the GSH level significantly (p<0.05). Pterostilbene also enhanced NQO1 activity significantly (p<0.05) at 12.5 μM and 50 μM. Hence, pterostilbene is a potential chemopreventive agent capable of modulation of detoxifiying enzyme levels in HT-29 cells.
Kratom (Mitragyna speciosa) has been used for medicinal and recreational purposes. It has reported analgesic, euphoric and antitussive effects via its action as an agonist at opioid receptors. It is illegal in many countries including Thailand, Malaysia, Myanmar, South Korea and Australia; however, it remains legal or uncontrolled in the UK and USA, where it is easily available over the Internet. We describe a case of kratom dependence in a 44-year-old man with a history of alcohol dependence and anxiety disorder. He demonstrated dependence on kratom with withdrawal symptoms consisting of anxiety, restlessness, tremor, sweating and cravings for the substance. A reducing regime of dihydrocodeine and lofexidine proved effective in treating subjective and objective measures of opioid-like withdrawal phenomena, and withdrawal was relatively short and benign. There are only few reports in the literature of supervised detoxification and drug treatment for kratom dependence. Our observations support the idea that kratom dependence syndrome is due to short-acting opioid receptor agonist activity, and suggest that dihydrocodeine and lofexidine are effective in supporting detoxification.
The effect of Brachiaria decumbens (signal grass) on drug-metabolizing enzymes was studied in sheep. After 14 d of grazing a pure signal grass pasture, significant declines were observed in hepatic aminopyrine N-demethylase and aniline 4-hydroxylase (phase I biotransformation) and in conjugative enzymes UDP-glucuronyltransferase and glutathione S-transferase. Kidney enzymes were significantly decreased except for UDP-glucuronyltransferase. Enzyme activities were also compared for normal sheep and cattle livers and kidneys. Lower activities were found in cattle, indicating that factors other than biotransformation are responsible for the clincial tolerance of cattle to B. decumbens toxicity.
It has been recognized extensively that studies of pharmacogenetics provide massive examples of causal relationship between genotypes and drug effectiveness to account for interindividual phenotypic variations in drug therapy. In most cases, cytochrome P450 (CYP) polymorphisms are one of the major variables that affecting those drug plasma concentration, drug detoxification and drug activation in humans. Thus, understanding of CYP polymorphisms can be crucially valuable in order to allow early and more accurate drug dosage prediction and improve the drug response accordingly. Despite the high level of homologous amino acid sequences, CYP2C9 and CYP2C19 genes are among the most important CYP genes which metabolize a wide range of clinically therapeutic drugs. Several critical reviews have been published relating to the aforementioned genes. However, this minireview aims to systematically merge reported studies on the SNPs frequencies of both genes concentrating only on Malaysian population. It is hoped that, the minireview can be an opener for new opportunities to reevaluate the evidence on the prevalence of CYP2C genes as a potential genetic factor influencing a particular drug efficacy and safety among Malaysian. Such evaluation can be developed to the next level of early prediction of better and specific drug treatment, thereby improving the drug response while helping the government in minimising the drug expenditures.
Glutathione S-transferase isoenzymes (GSTs) catalyze the conjugation reaction between glutathione and electrophilic
compounds. GSTs are involved in the detoxification of toxic and carcinogenic compounds, thus protecting the body from
toxic injuries. Tocotrienols are part of the vitamin E family and is believed to possess potent antioxidant activity. The
objective of this study was to determine the effect of increasing doses of tocotrienol rich fraction (TRF) supplementation
on liver GSTs gene and protein expression. A total of 30 male ICR white mice were divided into five groups (n=6 for each
group) and given treatment for 14 days through oral supplementation. Groups were divided as follows: - three groups
administered with TRF at doses of 200, 500 and 1000 mg/kg, respectively, a positive control group administered with 100
mg/kg butylated hydroxyanisole (BHA) and a control group administered with only the vehicle (corn oil). At day 15, the
mice were sacrificed and their livers isolated. Total RNA was extracted from the liver and quantitative real-time polymerase
chain reaction (qPCR) assays were performed to analyze GSTs gene expression. Total liver protein was also extracted
and the protein expression of GSTs was determined by Western blotting. The results showed that TRF oral supplementation
caused a significant dose-dependent increase in liver GST isoenzymes gene and protein expression, compared to controls.
In conclusion, TRF oral supplementation for 14 days resulted in increased gene and protein expression of GST isoenzymes
in mice liver dose-dependently, with the highest expression seen in mice treated with 1000 mg/kg TRF.
Metisa plana is a widespread insect pest infesting oil palm plantations in Malaysia. Farnesyl acetate (FA), a juvenile hormone analogue, has been reported to exert in vitro and in vivo insecticidal activity against other insect pests. However, the insecticidal mechanism of FA on M. plana remains unclear. Therefore, this study aims to elucidate responsive genes in M. plana in response to FA treatment. The RNA-sequencing reads of FA-treated M. plana were de novo-assembled with existing raw reads from non-treated third instar larvae, and 55,807 transcripts were functionally annotated to multiple protein databases. Several insecticide detoxification-related genes were differentially regulated among the 321 differentially expressed transcripts. Cytochrome P450 monooxygenase, carboxylesterase, and ATP-binding cassette protein were upregulated, while peptidoglycan recognition protein was downregulated. Innate immune response genes, such as glutathione S-transferases, acetylcholinesterase, and heat shock protein, were also identified in the transcriptome. The findings signify that changes occurred in the insect's receptor and signaling, metabolic detoxification of insecticides, and immune responses upon FA treatment on M. plana. This valuable information on FA toxicity may be used to formulate more effective biorational insecticides for better M. plana pest management strategies in oil palm plantations.
Nuclear factor-erythroid 2 p45 related factor 2 (Nrf2) is a primary transcription factor, protecting cells from oxidative stress by regulating a number of antioxidants and phase II detoxifying enzymes. Dietary components such as sulforaphane in broccoli and quercetin in onions have been shown to be inducers of Nrf2. Piper betle (PB) grows well in tropical climate and the leaves are used in a number of traditional remedies for the treatment of stomach ailments and infections among Asians. The aim of this study was to elucidate the effect of Piper betle (PB) leaves extract in Nrf2 signaling pathway by using 2 types of cells; mouse embryonic fibroblasts (MEFs) derived from wild-type (WT) and Nrf2 knockout (N0) mice.
The potential of isothiocyanates to antagonize the carcinogenicity of structurally diverse chemicals has been established in animals. A feasible mechanism of action involves protecting DNA by reducing the availability of the genotoxic metabolites of chemical carcinogens by either inhibiting their generation and/or stimulating their detoxification. In vivo as well as in vitro studies conducted in rat/human primary hepatocytes and precision-cut tissue slices have revealed that isothiocyanates can impair cytochrome P450 activity, including the CYP1 family which is the most active in the bioactivation of carcinogens, by virtue of being mechanism-based inactivators. The aromatic phenethyl isothiocyanate is the most effective of those studied, whereas aliphatic isothiocyanates such as sulforaphane and erucin necessitate high doses in order to manifest such effects that may not always be achievable through the diet. In all systems studied, isothiocyanates are strong inducers of detoxification enzyme systems including quinone reductase, glutathione S-transferase, epoxide hydrolase, and UDP-glucuronosyl transferase. Indeed, in smokers phenethyl isothiocyanate intake increases the urinary excretion of inactive mercapturate metabolites of toxic chemicals present in tobacco. Glucosinolates, the precursors of isothiocyanates, have also the potential to upregulate detoxification enzyme systems, but their contribution to the cancer chemoprevention linked to cruciferous vegetable consumption remains to be evaluated.
Bacopa monnieri and the constituents of this plant, especially bacosides, possess various neuropharmacological properties. Like drugs, some herbal extracts and the constituents of their extracts alter cytochrome P450 (CYP) enzymes, causing potential herb-drug interactions. The effects of Bacopa monnieri standardized extract and the bacosides from the extract on five major CYP isoforms in vitro were analyzed using a luminescent CYP recombinant human enzyme assay. B. monnieri extract exhibited non-competitive inhibition of CYP2C19 (IC50/Ki = 23.67/9.5 µg/mL), CYP2C9 (36.49/12.5 µg/mL), CYP1A2 (52.20/25.1 µg/mL); competitive inhibition of CYP3A4 (83.95/14.5 µg/mL) and weak inhibition of CYP2D6 (IC50 = 2061.50 µg/mL). However, the bacosides showed negligible inhibition of the same isoforms. B. monnieri, which is orally administered, has a higher concentration in the gut than the liver; therefore, this herb could exhibit stronger inhibition of intestinal CYPs than hepatic CYPs. At an estimated gut concentration of 600 µg/mL (based on a daily dosage of 300 mg/day), B. monnieri reduced the catalytic activities of CYP3A4, CYP2C9 and CYP2C19 to less than 10% compared to the total activity (without inhibitor = 100%). These findings suggest that B. monnieri extract could contribute to herb-drug interactions when orally co-administered with drugs metabolized by CYP1A2, CYP3A4, CYP2C9 and CYP2C19.