Effects of compound Anoectochilus roxburghii (Wall.) Lindl. oral liquid on relative metabolic enzymes and various biochemical indices in Wistar rats with isoniazid-induced liver injury.

Isoniazid (INH) is the first-line anti-tuberculosis drug in clinical practice, and its main adverse effect is drug-induced liver injury (DILI). This study aimed to investigate the hepatoprotective effect of Compound Anoectochilus roxburghii (Wall.) Lindl. Oral Liquid (CAROL) and to provide a new strategy for the search of potential drugs against INH-induced liver injury in Wistar rats. Animal experiment was based on INH (100 mg/kg) induced liver injury to explore the intervention effects of CAROL at doses of 1.35, 2.70, and 5.40 mL/kg. LC-QTOF-MS/MS was used to identify hepatoprotective components in CAROL and its' exposed components in rat serum. The hepatoprotective effect of CAROL was evaluated by pathological observation of rat liver tissue and changes in levels of biochemical indices and cytokines in serum or liver tissue. Of the 58 hepatoprotective components identified, 15 were detected in the serum of rats with liver-injured treated by high-dose CAROL. Results of animal experiments showed that the levels of various biochemical indexes and cytokines were significantly reversed with CAROL intervention. In particular, the expression level of cytokeratin-18 and high-mobility group box 1, as specific and sensitive indicators of DILI, was significantly reduced in the serum of rats with CAROL intervention compared with the INH model group. The same reversal was observed in the levels of TBIL, ALP, ALT, and AST in serum, as well as in the levels of TNF-α, IL-6, SOD, and MDA in liver tissue. For INH-metabolizing enzymes, an evident expression inhibition was observed in N-acetyltransferase 2 and glutathione S-transferases with CAROL intervention, which may be the key to controlling INH hepatotoxicity. CAROL has a favorable hepatoprotective effect on INH-induced liver injury. This study takes the first step in studying the hepatoprotective mechanism of CAROL against INH hepatotoxicity and provides reference for wider clinical applications.

Fetal protective effect of Indonesian propolis from Apis mellifera against rifampicin-pyrazinamide induced impaired pregnancy in BALB/c mice.

OBJECTIVES: Anti-tuberculosis drugs rifampicin and pyrazinamide combination in pregnancy can cause morphological, visceral and skeletal damage. Several studies showed that propolis improves pregnancy outcomes. This study aims to determine the fetal protective effect of propolis in BALB/c mice given the anti-tuberculosis drug combination rifampicin and pyrazinamide. METHODS: A total of 21 pregnant mice were randomly divided into three groups: the normal group (N) was given distilled water as a vehicle, the positive control group (RP) were given rifampicin 15 mg/kg BW, pyrazinamide 35 mg/kg BW and the treatment group (IP) were given rifampicin 15 mg/kg BB, pyrazinamide 35 mg/kg BW and propolis 400 mg/kg BW. The treatment was given during the period of organogenesis, from day 6 to day 15. Laparotomy was performed on the 18th day of pregnancy. Maternal and fetal body weight, fetal length, number of fetuses, and skeletal defects of fetuses were used as parameters to identify the teratogenic effect. All data were analyzed using the ANOVA. RESULTS: All groups significantly differed between maternal and fetal body weights (p<0.05). The administration of rifampicin-pyrazinamide and propolis during pregnancy did not significantly affect the number of fetuses (p>0.05). The administration of propolis protects the fetus from skeletal abnormalities. While in the RP and IP groups, we can find resorption sites and haemorrhagic. CONCLUSIONS: This study may suggest the protective effects of propolis against rifampicin pyrazinamide-induced impaired pregnancy.

Machine learning assisted methods for the identification of low toxicity inhibitors of Enoyl-Acyl Carrier Protein Reductase (InhA).

Tuberculosis (TB) is one of the life-threatening infectious diseases with prehistoric origins and occurs in almost all habitable parts of the world. TB mainly affects the lungs, and its etiological agent is Mycobacterium tuberculosis (Mtb). In 2022, more than 10 million people were infected worldwide, and 1.3 million were children. The current study considered the in-silico and machine learning (ML) approaches to explore the potential anti-TB molecules from the SelleckChem database against Enoyl-Acyl Carrier Protein Reductase (InhA). Initially, the entire database of ∼ 119000 molecules was sorted out through drug-likeness. Further, the molecular docking study was conducted to reduce the chemical space. The standard TB drug molecule's binding energy was considered a threshold, and molecules found with lower affinity were removed for further analyses. Finally, the molecules were checked for the pharmacokinetic and toxicity studies, and compounds found to have acceptable pharmacokinetic parameters and were non-toxic were considered as final promising molecules for InhA. The above approach further evaluated five molecules for ML-based toxicity and synthetic accessibility assessment. Not a single molecule was found toxic and each of them was revealed as easy to synthesise. The complex between InhA and proposed and standard molecules was considered for molecular dynamics simulation. Several statistical parameters showed the stability between InhA and the proposed molecule. The high binding affinity was also found for each of the molecules towards InhA using the MM-GBSA approach. Hence, the above approaches and findings exposed the potentiality of the proposed molecules against InhA.

Synergistic toxicity with copper contributes to NAT2-associated isoniazid toxicity.

Anti-tuberculosis (AT) medications, including isoniazid (INH), can cause drug-induced liver injury (DILI), but the underlying mechanism remains unclear. In this study, we aimed to identify genetic factors that may increase the susceptibility of individuals to AT-DILI and to examine genetic interactions that may lead to isoniazid (INH)-induced hepatotoxicity. We performed a targeted sequencing analysis of 380 pharmacogenes in a discovery cohort of 112 patients (35 AT-DILI patients and 77 controls) receiving AT treatment for active tuberculosis. Pharmacogenome-wide association analysis was also conducted using 1048 population controls (Korea1K). NAT2 and ATP7B genotypes were analyzed in a replication cohort of 165 patients (37 AT-DILI patients and 128 controls) to validate the effects of both risk genotypes. NAT2 ultraslow acetylators (UAs) were found to have a greater risk of AT-DILI than other genotypes (odds ratio [OR] 5.6 [95% confidence interval; 2.5-13.2], P = 7.2 × 10-6). The presence of ATP7B gene 832R/R homozygosity (rs1061472) was found to co-occur with NAT2 UA in AT-DILI patients (P = 0.017) and to amplify the risk in NAT2 UA (OR 32.5 [4.5-1423], P = 7.5 × 10-6). In vitro experiments using human liver-derived cell lines (HepG2 and SNU387 cells) revealed toxic synergism between INH and Cu, which were strongly augmented in cells with defective NAT2 and ATP7B activity, leading to increased mitochondrial reactive oxygen species generation, mitochondrial dysfunction, DNA damage, and apoptosis. These findings link the co-occurrence of ATP7B and NAT2 genotypes to the risk of INH-induced hepatotoxicity, providing novel mechanistic insight into individual AT-DILI susceptibility. Yoon et al. showed that individuals who carry NAT2 UAs and ATP7B 832R/R genotypes are at increased risk of developing isoniazid hepatotoxicity, primarily due to the increased synergistic toxicity between isoniazid and copper, which exacerbates mitochondrial dysfunction-related apoptosis.

Potential underlying mechanisms of ethambutol induced optic neuropathy: Evidence from in vitro to clinical studies.

Ethambutol is an antibiotic widely used for treatment of Mycobacterium species. Although it is safe to use in patients, the ocular toxic impact, including optic neuropathy and retinopathy, can be observed in patients using ethambutol. After discontinuation of the drug, the ocular toxic effects can be reversible in some patients, but some are not. Ethambutol-induced optic neuropathy has been recognized for more than six decades and the prevalence of optic neuropathy from a standard dose of ethambutol has been reported as 0.7-1.29%. Several factors associated with ethambutol-induced optic neuropathy include dosage/duration of drug, the medical conditions of patients such as renal and hepatic dysfunction and preexisting mitochondrial mutations. Currently, there is no specific treatment and prevention of ethambutol-induced optic neuropathy. In addition, the potential underlying mechanisms of ethambutol-induced optic neuropathy is still unclear. Therefore, this review aimed to summarize and discuss evidence from clinical, in vitro, and in vivo studies in order to explore the potential pathophysiology of ethambutol-induced optic neuropathy. Any contradictory findings are also included and discussed. The insights gained from the review will facilitate the discovery of novel approaches for prevention and treatment of optic neuropathy-induced by ethambutol.

Near-infrared molecular sensor for visualizing and tracking ONOO- during the process of anti-tuberculosis drug-induced liver damage.

Isoniazid (INH) and pyrazinamide (PZA) are both the first-line anti-tuberculosis drugs in clinical treatment. It is notable that there are serious side effects of the drugs along with upregulation of reactive nitrogen species, mainly including peripheral neuritis, gastrointestinal reactions, and acute drug-induced liver injury (DILI). Among them, DILI is the most common clinical symptom as well as the basic reason of treatment interruption, protocol change, and drug resistance. As vital reactive nitrogen species (RNS), peroxynitrite (ONOO-) has been demonstrated as a biomarker for evaluation and pre-diagnosis of drug-induced liver injury (DILI). In this work, we developed a red-emitting D-π-A type fluorescence probe DIC-NP which was based on 4'-hydroxy-4-biphenylcarbonitrile modified with dicyanoisophorone as a fluorescent reporter and diphenyl phosphinic chloride group as the reaction site for highly selective and sensitive sensing ONOO-. Probe DIC-NP displayed a low detection limit (14.9 nM) and 60-fold fluorescent enhancement at 669 nm in the sensing of ONOO-. Probe DIC-NP was successfully applied to monitor exogenous and endogenous ONOO- in living HeLa cells and zebrafish. Furthermore, we verified the toxicity of isoniazid (INH) and pyrazinamide (PZA) by taking the oxidative stress induced by APAP as a reference, and successfully imaged anti-tuberculosis drug-induced endogenous ONOO- in HepG2 cells. More importantly, we developed a series of mice models of liver injury and investigated the hepatotoxicity caused by the treatment of anti-tuberculosis drugs. At the same time, H&E of mice organs (heart, liver, spleen, lung, kidney) further confirmed the competence of probe DIC-NP for estimating the degree of drug-induced liver injury, which laid a solid foundation for medical research.

Scopoletin a potential phytochemical therapy for antitubercular treatment drug induced liver injury (ATT-DILI) model in Wistar rats.

OBJECTIVES: The hepatoprotective properties of scopoletin have been explored in carbon tetrachloride (CCl4) induced liver injury but not in drug-induced liver injury (DILI) scenarios. Only N-acetyl-cysteine (NAC) has proven efficacy in DILI treatment. Accordingly, we conducted a study to assess the hepatoprotective action of scopoletin in the anti-tubercular treatment (ATT)-DILI model in Wistar rats, if any. METHODS: A total of 36 rats were evaluated, with six in each group. A 36-day ATT at 100 mg/kg dose for isoniazid, 300 mg/kg for rifampicin and 700 mg/kg for pyrazinamide were fed to induce hepatotoxicity in rats. Group I and II-VI received normal saline and ATT, respectively. Oral scopoletin (1,5 and 10 mg/kg) and NAC 150 mg/kg were administered in groups III, IV, V and VI, respectively, once daily for the last 15 days of the experiment. LFT monitoring was performed at baseline, days 21, 28, and 36. Rats were sacrificed for the histopathology examination. RESULTS: Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and bilirubin levels were significantly increased in group II (receiving ATT) compared to normal control on day 28 and day 36 (p<0.05). All three doses of scopoletin and NAC groups led to the resolution of AST, ALT, ALP, and bilirubin changes induced by ATT medications effect beginning by day 28 and persisting on day 36 (p<0.01). An insignificant effect was observed on albumin and total protein levels. The effect was confirmed with antioxidants and histopathology analysis. CONCLUSIONS: The study confirms the hepatoprotective efficacy of scopoletin in a more robust commonly encountered liver injury etiology.

Evaluation of Acute and Sub-Acute Toxicity, Oxidative Stress and Molecular Docking of Two Nitrofuranyl Amides as Promising Anti-Tuberculosis Agents.

Tuberculosis (TB) remains a widespread infectious disease and one of the top 10 causes of death worldwide. Nevertheless, despite significant advances in the development of new drugs against tuberculosis, many therapies and preventive measures do not lead to the expected favorable health results for various reasons. The aim of this study was to evaluate the acute and sub-acute toxicity and oxidative stress of two selected nitrofuranyl amides with high in vitro antimycobacterial activity. In addition, molecular docking studies were performed on both compounds to elucidate the possibilities for further development of new anti-tuberculosis candidates with improved efficacy, selectivity, and pharmacological parameters. Acute toxicity tests showed that no changes were observed in the skin, coat, eyes, mucous membranes, secretions, and vegetative activity in mice. The histological findings include features consistent with normal histological architecture without being associated with concomitant pathological conditions. The observed oxidative stress markers indicated that the studied compounds disturbed the oxidative balance in the mouse liver. Based on the molecular docking, compound DO-190 showed preferable binding energies compared to DO-209 in three out of four targets, while both compounds showed promising protein-ligand interactions. Thus, both studied compounds displayed promising activity with low toxicity and can be considered for further evaluation and/or lead optimization.

Design, synthesis and antitubercular activity of novel N-(amino)piperazinyl benzothiazinones with improved safety.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) remains a major global health problem and new therapeutic antitubercular agents are urgent needed. Among the novel antituberculosis drugs in the pipeline, Benzothiazinones (BTZs) are among the most potent antituberculosis agents against both drug-susceptible and multidrug-resistant (MDR) tuberculosis. Our group has focused on structural modifications of the side chain at C-2 position of the BTZ core and WAP-2101/2102 with excellent in vitro activity were discovered in our lab. However, the severe in vivo toxicity was observed during subsequent acute toxicity evaluation. Herein, a series of novel N-(amino)piperazinyl benzothiazinone derivatives were designed and synthesized as new anti-TB agents to reduce the in vivo toxicity. Our results show that majority of them exhibit the same potent or comparable activity against both MTB H37Rv and MDR-MTB strains (MIC: 4.00 - <1 ng/mL) as PBTZ169. Especially, compound 2c with low cardiac toxicity, low cell cytotoxicity and acceptable oral pharmacokinetic (PK) profiles have low acute toxicity in mice (LD50 > 500 mg/kg), suggesting it may serve as a promising lead compound for further antitubercular drug discovery.

Gut microbiota affects sensitivity to immune-mediated isoniazid-induced liver injury.

Isoniazid (INH) is a highly effective single and/or combined first-line anti-tuberculosis (anti-TB) therapy drug, and the hepatotoxicity greatly limits its clinical application. INH-induced liver injury (INH-DILI) is a typical immune-mediated idiosyncratic drug-induced liver injury. Existing mechanisms including genetic variations in drug metabolism and immune responses cannot fully explain the differences in susceptibility and sensitivity to INH-DILI, suggesting that other factors may be involved. Accumulating evidence indicates that the development and severity of immune-mediated liver injury is related to gut microbiota. In this study, INH exposure caused liver damage, immune disregulation and microbiota profile alteration. Depletion of gut microbiota ameliorated INH-DILI, and improved INH-DILI-associated immune disorder and inflammatory response. Moreover, hepatotoxicity of INH was ameliorated by fecal microbiota transplantation (FMT) from INH-treated mice. Notably, Bifidobacterium abundance was significantly associated with transaminase levels. In conclusion, our results suggested that the effect of gut microbiota on INH-DILI was related to immunity, and the difference in INH-DILI sensitivity was related to the structure of gut microbiota. Changes in the structure of gut microbiota by continuous exposure of INH resulted in the tolerance to liver injury, and probiotics such as Bifidobacterium might play an important role in INH-DILI and its "adaptation" phenomenon. This work provides novel evidence for elucidating the underlying mechanism of difference in individual's response to INH-DILI and potential approach for intervening anti-TB drug liver injury by modulating gut microbiota.

Naringenin protects hepato-renal tissues against antituberculosis drugs induced toxic manifestations by modulating interleukin-6, insulin like growth factor-1, biochemical and ultra-structural integrity.

BACKGROUND: The antituberculosis drugs (ATDs), isoniazid, rifampicin, pyrazinamide and ethambutol prompt extreme hepatic and renal damage during treatment of tuberculosis. The present study aimed to investigate protective potential of naringenin against ATDs induced hepato-renal injury. METHODS: Rats were administered with ATDs (pyrazinamide; 210, ethambutol; 170, isoniazid; 85, rifampicin; 65 mg/kg b.wt) orally for 8 weeks (3 days/week) followed by naringenin at three different doses (10, 20 and 40 mg/kg b.wt) conjointly for 8 weeks (3 days/week alternately to ATDs administration) and silymarin (50 mg/kg b.wt) as positive control. RESULTS: Exposure to ATDs caused significant increase in interleukin-6 (IL-6), triglycerides, cholesterol, bilirubin whereas depletion in insulin like growth factor-1 (IGF-1), albumin and glucose in serum. Endogenous antioxidant enzymes glutathione reductase (GR), glutathione peroxidase (GPx) and glucose-6-phosphate-dehydrogenase (G-6-PDH) were diminished in liver and kidney tissues with parallel increase in triglycerides, cholesterol, microsomal LPO and aniline hydroxylase (CYP2E1 enzyme). Ultra-structural observations of liver and kidney showed marked deviation in plasma membranes of various cellular and sub-cellular organelles after 8 weeks of exposure to ATDs. CONCLUSIONS: Conjoint treatment of naringenin counteracted ATDs induced toxic manifestations by regulating IL-6, IGF-1, CYP2E1, biochemical and ultra-structural integrity in a dose dependent manner. Naringenin has excellent potential to protect ATDs induced hepato-renal injury by altering oxidative stress, modulation of antioxidant enzymes, serum cytokines and ultra-structural changes.

In vitro and in vivo local tolerability of a synergistic anti-tuberculosis drug combination intended for pulmonary delivery.

A drug combination, vancomycin (VAN) plus tetrahydrolipstatin (THL), has demonstrated an effective synergistic action in vitro against Mycobacterium tuberculosis (Mtb). The poor oral bioavailability of VAN and THL and the predominant tropism of Mtb infection to the lungs make their pulmonary administration very attractive. To evaluate their local tolerability, bronchial cells, alveolar cells and monocytes were exposed to concentrations around and above their minimal inhibitory concentration (MIC). The VAN had no inhibitory activity on the tested human cell lines, even at a concentration 125 times higher than its MIC, whereas the THL, alone or in combination with VAN, presented a cytostatic action. Monolayer epithelium showed no significant irreversible damage at concentrations up to 100 times the combination MIC. BALB/cAnNRj mice exposed to concentration of 50 times the combination MIC delivered endotracheally 3 times a week for 3 weeks showed no clinical signs or significant weight loss. The increase of proinflammatory biomarkers (i.e., IL-1, IL-6, TNF-α and proportion of inflammatory cells) and cytotoxicity in bronchoalveolar lavage fluid (BALF) were non-significant. Lung histopathology did not show significant tissue damage. The VAN/THL combination at doses up to 50 times the combination MIC is found to be thus well tolerated by pulmonary route. This study is a promising result and encouraging further investigations of pulmonary administration of VAN/THL combination as dry powder for anti-tuberculosis treatment.

Protective role of Avena fatua against drug-induced liver toxicity.

The study was conducted to examine the protective potential of ethanol seed extract (ESEt) of Avena fatua (wild oats) against antituberculosis drug (ATD)-induced hepatotoxicity in rats. Four groups of rats (n=6) were used. Of which, three groups were given ATD (Rimstar 900mg/15kg) and divided them into hepatotoxic control (distilled water 1mL/kg), positive control (silymarin 200mg/kg) and test group (ESEt 800mg/kg). The fourth was the normal control group treated only with distilled water (1mL/kg). All treatments were orally administered in their respective groups for 26 days. On the 27thday, rats were decapitated. Body and liver weights were measured whereas serum and liver samples were collected for biochemical and histopathological assessments. The rats treated with silymarin and ESEt showed a significant decrease (p<0.05, 0.01& 0.0001) in liver enzymes including alanine & aspartate transaminases, gamma glutamyltranspeptidase and alkaline phosphatase. ESEt also improved total bilirubin (particularly indirect bilirubin), total protein, albumin and low density lipoprotein cholesterol levels in test group. The hepatoprotective ability of extract was also evident by histological study of liver tissues of the test group that showed normal architecture as compared to liver of ATD treated hepatotoxic control group displayed heterogeneous hepatocytes, inflamed central vein, fatty deposits, enlarged sinusoid, Kupffer's cells infiltration, hypertrophy and fibrosis. In conclusion, ESEt of A.fatua is hepatoprotective in nature which may be due to the presence of total phenols and flavonoids already reported from the seeds of this plant.

The role of the farnesoid X receptor in quadruple anti-tuberculosis drug-induced liver injury.

Anti-tuberculosis drugs-induced liver injury may be associated with the hepatic farnesoid X receptor (FXR). However, the relationship between isoniazid, rifampicin, pyrazinamide and ethambutol (HRZE) coadministration-induced liver injury and FXR has not been clarified. The purpose of this study was to clarify the role of FXR in HRZE-induced liver injury. To measure indices of liver injury, blood samples were collected from clinical tuberculosis patients who had taken HRZE for approximately two months; in these patients serum total bile acids were increased, while other hepatic biochemical indexes showed no significant changes. When Wistar rats were orally administered isoniazid (30 or 60 mg/kg) + rifampicin (45 or 90 mg/kg) + pyrazinamide (150 or 300 mg/kg) + ethambutol (75 or 150 mg/kg) in combination for 15 days, the expression and function of FXR was up-regulated, and hepatic bile acids were decreased. However, following 30 days of HRZE treatment the expression and function of FXR was down-regulated and bile acids accumulated in the liver, suggestive of hepatotoxicity. Treatment of HepaRG cells with HRZE lead to time- and dose- dependent cytotoxicity, with the expression of FXR up-regulated in early stage, but down-regulated with prolonged HRZE treatment, consistent with the results of animal experiments. In summary, HRZE may upregulate FXR with short-term administration, but more prolonged treatment appears to suppress FXR function, resulting in hepatic bile acid accumulation.

Analysis of time-series gene expression data to explore mechanisms of isoniazid-induced liver toxicity.

Isoniazid (INH) is a first-line anti-tuberculosis drug which can cause idiosyncratic liver injury, while the underlying mechanisms need to be further elucidated. In this study, we explored the time series gene expression profiling of a hepatocyte cell line under isoniazid treatment. Through cluster analysis and enrichment analysis of differentially expressed genes, we revealed a total of 6 gene clusters and a series of pathways related to hepatotoxicity, and 13 key candidate genes were identified according to the protein-protein interaction (PPI) network analysis and maSigPro analysis. These findings lay a foundation for understanding the mechanisms of isoniazid -induced liver toxicity and provide new target genes for the monitoring and treatment of INH-induced hepatotoxicity in the future.

Discovery of potent antitubercular agents: Design, synthesis and biological evaluation of 4-(3-(4-substitutedpiperazin-1-yl)-quinoxalin-2-yl)-naphthalen-1-ol analogues.

A series of twenty-five novel 4-(3-(4-substituted piperazin-1-yl)-quinoxalin-2-yl)-naphthalen-1-ol analogues were synthesized, characterized and screened for in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain. These compounds exhibited minimum inhibitory concentration in the range of 1.56-50 µg/mL. Among these derivatives, compounds 5a, 5b, 5f, 5m, 5p, and 5r displayed moderate activity (MIC 6.25 µg/mL). Compounds 5c, 5d, 5g, 5l, and 5o showed significant antitubercular activity (MIC 3.125 µg/mL), while compounds 5h, 5n, and 5q exhibited potent antitubercular activity (MIC 1.56 µg/mL). In addition, MTT assay was performed on the active analogues of the series against mouse macrophage cells to assess the cytotoxic effect of the newly synthesized compounds, and a selectivity index of the compounds was established. Selectivity index values of the most active compounds (5h, 5n, and 5q) are >47, indicating the compounds' suitability for further potential drug development. A molecular docking study was performed to understand the putative binding mode and binding strength of the selected significantly active and weakly active compounds with the target enzyme mycobacterial topoisomerase II using moxifloxacin as standard. In-silico ADME prediction and bioavailability studies of the titled compounds obey Lipinski's rule of five and Jorgensen's rule of three. To further ascertain the structure of the compounds, a suitable single crystal for the compounds 5a, 6, and 7d was developed and studied.

Antimycobacterial, cytotoxic, and anti-inflammatory activities of Artemisialudoviciana.

ETHNOPHARMACOLOGICAL RELEVANCE: A third part of the world population has been exposed to the pathogen Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB). TB is a deadly disease, and its treatment has been hampered because of the lack of new antibiotics or the development of new antimycobacterial agents against this pathogen. The situation is aggravated because of the appearance of multidrug-resistant strains. In Mexican traditional medicine, records showed Artemisia ludoviciana for the treatment of TB. Thus, the combination of antibiotics and plant extracts might represent new antimycobacterial agents as an attractive alternative. MATERIALS AND METHODS: The biological activities of ethanol extract obtained from A. ludoviciana were evaluated for its antimycobacterial activities using an M. tuberculosis clinical isolate. Also, the toxicity of the extracts was assessed ex vivo and in vivo using the human-derived macrophages cell line (THP-1) and the Artemia spp. model, respectively. Lastly, the inflammatory response of macrophages exposed to the extracts was also evaluated. RESULTS: The ethanol extract of A. ludoviciana showed antimycobacterial activity with a MIC of 250 µg/mL against a clinical strain of M. tuberculosis. Ex vivo cytotoxicity using the THP-1 cell line incubated with the ethanol extract showed an IC50 of 20 µg/mL. On the other hand, the Artemia model's toxicity test showed moderate toxicity when the A. ludoviciana extract was tested with LC50 of 195.64 µg/mL. Analysis of the inflammatory response of THP-1 cells exposed to the same extract showed no increase in secreted interleukine-6 and -10. Also, no effect was observed in the pro-inflammatory tumor necrosis factor-α cytokine level. Moreover, a chemical profile of the extracts identified achillin as the major component in the ethanol extract, along with other minor components such as thujone and stigmasterol. CONCLUSIONS: We showed that the ethanol extract of A. ludoviciana possessed antimycobacterial activity and could potentially be used to supplement the antibiotic treatment of TB.

Exploration of the Plausible Mechanism of Ethambutol Induced Ocular Toxicity by Using Proteomics Informed Physiologically Based Pharmacokinetic (PBPK) Modeling.

PURPOSE: Ethambutol (EMB) is a first-line anti-tubercular drug that is known to cause optic neuropathy. The exact mechanism of its eye toxicity is unknown; however, proposition is metal chelating effect of both EMB and its metabolite 2,2'-(ethylenediamino)-dibutyric acid (EDBA). The latter is formed by sequential metabolism of EMB by alcohol dehydrogenases (ADHs) and aldehyde dehydrogenases (ALDHs). The purpose of this study was to predict the levels of drug and EDBA in the eye using physiologically based pharmacokinetic (PBPK) modeling. METHODS: The PBPK model of EMB was developed using GastroPlus. The intrinsic hepatic clearance of ALDH, calculated by the model, was scaled down using proteomics data to estimate the rate of formation of EDBA in the eye. Additionally, the comparative permeability of EMB and EDBA was assessed by employing in silico and in vitro approaches. The rate of formation of EDBA in the eye and permeability data were then incorporated in a compartmental model to predict the ocular levels of EMB and EDBA. RESULTS: The simulation results of compartmental model highlighted that there was an on-site formation of EDBA upon metabolism of EMB. Furthermore, in silico and in vitro studies revealed that EDBA possessed much lower permeability than EMB. These observations meant that once EDBA was formed in the eye, it was not permeated out and hence achieved higher ocular concentration. CONCLUSION: The on-site formation of EDBA in the eye, its higher local concentration due to lower ocular clearance and its pre-known characteristic to chelate metal species better explains the ocular toxicity shown by EMB.

Neurodevelopmental toxicity of pyrazinamide to larval zebrafish and the restoration after intoxication withdrawal.

To investigate the neurotoxicity of pyrazinamide (PZA) to larval zebrafish, the PZA effects were assessed followed by its mechanism being explored. Same as isoniazid (INH), this compound is a first-line anti-tuberculosis drug and is suggested to be a risk that inducing nerve injury with long-term intoxication. Our findings indicated that zebrafish larvae obtained severe nerve damage secondary to constant immersion in various concentrations of PZA (i.e., 0.5, 1.0, and 1.5 mM) from 4 hpf (hours post fertilization) onwards until 120 hpf. The damage presented as dramatically decrease of locomotor capacity and dopaminergic neuron (DAN)-rich region length in addition to defect of brain blood vessels (BBVs). Moreover, PZA-administrated zebrafish showed a decreased dopamine (DA) level and downregulated expression of neurodevelopment-related genes, such as shha, mbp, neurog1, and gfap. However, secondary to 48-h restoration in fish medium (i.e., at 168 hpf), the neurotoxicity described above was prominently ameliorated. The results showed that PZA at the concentrations we tested was notably neurotoxic to larval zebrafish, and this nerve injury was restorable after PZA withdrawing. Therefore, this finding will probably provide a reference for clinical medication.