Antitubercular Drug Isoniazid Research Articles

Structural Studies on Mycobacterial NudC Reveal a Class of Zinc Independent NADH Pyrophosphatase

Non-tuberculous mycobacteria (NTM) have emerged as an increasing threat to public health, due to the extreme antibiotic resistance. NADH pyrophosphatase (NudC) was proposed involving in mycobacterial resistance to the first line anti-tubercular drug isoniazid (INH) or its analog ethionamide (ETH), by hydrolyzing their NAD modified active forms (NAD-INH and NAD-ETH). In this study, we performed enzymatic and structural studies on NudC from M. abscessus (NudCMab), which is highly resistant to isoniazid and emerging as the most worrisome NTM. We determined the crystal structures of NudCMab in apo form, substrate NAD-bound form and product AMP-bound form. We observed the mode for the Nudix motif of NudCMab capturing the pyrophosphate group of NAD mediated by three divalent cation ions, which provides details for understanding the mechanism on NudC hydrolyzing NAD(H) or NAD-capped substrate. Interestingly, our structures revealed a novel subclass NudC from mycobacteria characterized by a unique arginine residue on the conserved QPWPFPxS motif, as well as a unique tower domain that replaces a well-defined zinc-binding motif in E.coli NudC and catalytic domain of mammalian Nudt12. Thus, our structural studies on NudCMab not only present a class of zinc independent NADH pyrophosphatase in mycobacteria, but also may facilitate the design of NudC inhibitors for the treatment of mycobacteria infections in combination with INH or ETH.

An Unusual Case of CNS Tuberculoma in a 19-Year-Old Man

Background: Tuberculosis (TB) is ranked as one of the top 10 causes of death. Mycobacterium tuberculosis (M. TB) infection, the causative organism for TB affects approximately a quarter of the global population placing a burden on the healthcare system. Central nervous system tuberculosis (CNS TB) is seen in 5 to 10% of extrapulmonary TB cases and has the highest mortality. CNS tuberculoma is one of its manifestation. Clinical presentation of CNS tuberculoma depends on its location within the CNS and commonly include headache, seizures, and focal neurological deficits, due to the presence of a space occupying lesion, although patients can be asymptomatic. We report the case of a 19yr old man who had an unusual presentation of CNS tuberculoma, highlighting its clinical presentation, diagnosis and treatment. Case Presentation: Index patient is a 19-year-old male college student who resides in a city. He presented with 15 days history of fever, headache, vomiting, vertigo, ataxia, and inability to concentrate. He received antimalarial, anti typhoid and body booster medications but had no improvement and had a history of weight loss despite no dietary change. He had never been diagnosed with TB and had all his childhood vaccinations given. Plain Magnetic Resonance Imaging (MRI) brain scan done revealed a posterior fossa mass lesion with perilesional edema. Futher, a contrast MRI brain scan showed multiple ring-enhancing conglomerates of lesion around the tentorium on the posterior fossa with intense contrast enhancement. The largest of this mass measured 4.5 cm x 2.5 cm x 2.5 cm in the right superior cerebellum compressing the 4th ventricle and with effacement of the cerebellopontine angle. Lastly, an MRI spectrometry revealed elevated lipid lactate peak. His chest x-ray was unremarkable. Other blood parameters were essentially within range with the exception of Erythrocyte ESR and mantoux test. He received antitubercular drug (Isoniazid, Rifampin, Pyrazinamide, Ethambutol, Levoflox and Streptomycin) for 18th months with complete remission. Conclusion: CNS tuberculomas are tuberculous masses that can be located anywhere from the brain to spinal cord. Advanced diagnostic modalities may guide clinicians towards making it's diagnosis. Treatment maybe medical (use of antitubercular drugs) or surgical excision with medical therapy being first choice. While the index patient had no obvious risk factors for his disease, his BCG vaccination pose a possible source of his exposure to TB infection. More research is needed on this however.

Development of a HPLC Method for Analysis of a Combination of Clofazimine, Isoniazid, Pyrazinamide, and Rifampicin Incorporated into a Dermal Self-Double-Emulsifying Drug Delivery System.

We describe the development and validation of a new high performance liquid chromatography (HPLC) method for analysis of a combination of the first-line anti-tubercular drugs isoniazid, pyrazinamide, and rifampicin together with clofazimine. This is a unique challenge since clofazimine and rifampicin are relatively highly lipophilic drugs, whereas isoniazid and pyrazinamide are considerably more hydrophilic. Thus, clear separation of peaks and quantification of four individual drugs can present difficulties during the development of an analytical method. Detection was established at two wavelengths-254 nm for isoniazid and pyrazinamide and 320 nm for clofazimine and rifampicin. Gradient elution was employed using 0.1% aqueous formic acid (A) and acetonitrile (B); clear separation of the four drugs was achieved within 10 min. A linear relationship was indicated by a correlation coefficient (r2) of 0.9999 for each anti-tubercular drug, respectively. The limit of detection (LOD) for the individual drugs was 0.70 µg/mL (isoniazid), 0.30 µg/mL (pyrazinamide), 0.20 µg/mL (rifampicin) and 0.20 µg/mL (clofazimine). Precision experiments rendered a mean recovery percentage of 101.25% (isoniazid), 98.70% (pyrazinamide), 99.68% (rifampicin) and 97.14% (clofazimine). This HPLC method was validated and is reliable, repeatable, and accurate for the purpose of conducting simultaneous HPLC analyses of the four anti-tubercular drugs.

Adjunct Therapy With All-trans-Retinoic Acid Improves Therapeutic Efficacy Through Immunomodulation While Treating Tuberculosis With Antibiotics in Mice.

Tuberculosis is the second leading infectious killer after coronavirus disease 2019 (COVID-19). Standard antitubercular drugs exhibit various limitations like toxicity, long treatment regimens, and lack of effect against dormant and drug-resistant organisms. Here, we report that all-trans-retinoic acid (ATRA) improves Mycobacterium tuberculosis clearance in mice during treatment with the antitubercular drug isoniazid. Interestingly, ATRA promoted activities of lysosomes and mitochondria, and production of various inflammatory mediators in macrophages. Furthermore, ATRA upregulated the expression of genes of lipid metabolism pathways in macrophages. We demonstrated that ATRA activated the MEK/ERK pathway in macrophages in vitro and MEK/ERK and p38 MAPK pathways in mice. Finally, ATRA induced both Th1 and Th17 responses in lungs and spleens of M. tuberculosis-infected mice. Together, these data indicate that ATRA provides beneficial adjunct therapeutic value by modulating MEK/ERK and p38 MAPK pathways and thus warrants further testing for human use.

Experimental, spectroscopic, and theoretical investigation on structural and anticancer activities of Schiff bases derived from isonicotinohydrazide

Isoniazid hydrazones are promising possibilities as medicines since they have preserved efficacy and are less toxic and resistant to resistance than parent Isoniazid (INH). Here, we have synthesized a series of Schiff bases (INH1–9) derived from a clinically approved antitubercular drug Isoniazid (INH). These synthesized ligands have been characterized by various spectroscopic techniques like IR, UV–vis., NMR, HRMS, etc. Moreover, single crystal of three derivatives viz. INH4, INH8, and INH9 has been determined and they crystallize in monoclinic crystal system. Hirshfeld surface analysis has been performed to ascertain intermolecular interactions present in these compounds. The molecular geometry optimization and vibrational analysis of these compounds were performed using density functional theory (DFT) studies utilizing B3LYP/6–31++G(d, p) basis set. The TD-DFT analysis was also performed to understand electronic transitions and the nature of FMO in these compounds. There was a good correlation found between theoretical and experimental values, thereby confirming the molecular structures of synthesized compounds. Molecular docking studies were performed to obtain more insights on potential anticancer activities of these compounds along with standard anticancer drugs 5-fluorouracil and Tamoxifen against MDM2 (4HG7) protein. The outcome revealed a significant binding affinity of these compounds with target protein even better than 5-fluorouracil and comparable to Tamoxifen. The compounds (INH4 and INH9) having the strongest binding affinity with the target protein are further experimentally evaluated for their in-vitro cytotoxic action on Dalton's lymphoma cells employing MTT assay, fluorescence microscopy, and flow cytometry. IC50 value (150 µg/ml) of this compound is equated with before-reported complexes/molecules/extracts and found it has better or comparable cytotoxicity.

Respirable konjac glucomannan microparticles as antitubercular drug carriers: Effects of in vitro and in vivo interactions

Pulmonary delivery of drugs is potentially beneficial in the context of lung disease, maximising drug concentrations in the site of action. A recent work proposed spray-dried konjac glucomannan (KGM) microparticles as antitubercular drug (isoniazid and rifabutin) carriers to treat pulmonary tuberculosis. The present work explores in vitro and in vivo effects of these microparticles, focusing on the ability for macrophage uptake, the exhibited antibacterial activity and safety issues. Efficient uptake of KGM microparticles by macrophages was demonstrated in vitro, while the antitubercular activity of the model drugs against Mycobacterium bovis was not affected by microencapsulation in KGM microparticles. Despite the good indications provided by the developed system, KGM is not yet approved for pulmonary applications, which is a limiting characteristic. To reinforce the available data on the performance of the material, safety parameters were evaluated both in vitro and in vivo, showing promising results. No significant cell toxicity was observed at concentrations considered realistic for lung delivery approaches (up to 125 μg/mL) when lung epithelial cells and macrophages were exposed to KGM microparticles (both drug-loaded and unloaded). Finally, no signs of systemic or lung inflammatory response were detected in mice after receiving 10 administrations of unloaded KGM microparticles.

Hepatoprotective potential of diosmin against hepatotoxic effect of isoniazid and rifampin in wistar rats.

The treatment of tuberculosis with isoniazid and rifampin is associated with hepatocellular damage. Therefore, the study was designed to evaluate the hepatoprotective potential of diosmin against hepatotoxic effect of isoniazid and rifampin in Wistar rats. Hepatotoxicity was induced by administering isoniazid and rifampin (100mg/kg), whereas diosmin was given as treatment control. Markers of liver function (ALT, AST, ALP and bilirubin), inflammatory cytokines (TNFα, IL-6 and IL-1β), apoptosis (caspase-3), oxidative stress parameters (LPO, GSH, CAT and SOD) and histological changes in liver were assessed in normal, hepatotoxic control and treatment groups. The administration of isoniazid and rifampin significantly increased markers of liver dysfunction (ALT, AST, ALP and bilirubin), cytokines (TNFα, IL-6 and IL-1β) and apoptosis (caspase-3). However, daily dosing of diosmin significantly reduced these markers of liver dysfunction, inflammatory cytokines and apoptosis to near normal levels. Additionally, markers of hepatocellular oxidative stress parameters were significantly altered as evident from increased LPO level and decreased endogenous antioxidants such as GSH, SOD and CAT in isoniazid-and rifampin-treated hepatotoxic group. It was observed that diosmin treatment reduced high levels of LPO and demonstrated significant improvement in antioxidant levels. Histological studies of liver also supported our biochemical findings, which are also manifested as diosmin treatment exhibited protection against hepatocellular degeneration and inflammation. Results of the present study demonstrate hepatoprotective potential of diosmin against isoniazid-and rifampin-treated hepatotoxicity. Thus, we conclude that diosmin may be used along with anti-tubercular drugs (isoniazid and rifampin) in tuberculosis patients to overcome their hepatotoxic adverse effect.

Elucidating the function of hypothetical PE_PGRS45 protein of Mycobacterium tuberculosis as an oxido-reductase: a potential target for drug repurposing for the treatment of tuberculosis

Mycobacterium tuberculosis (Mtb) encodes a total of 67 PE_PGRS proteins and definite functions of many of them are still unknown. This study reports PE_PGRS45 (Rv2615c) protein from Mtb as NADPH dependent oxido-reductase having substrate specificity for fatty acyl Coenzyme A. Computational studies predicted PE_PGRS45 to be an integral membrane protein of Mtb. Expression of PE_PGRS45 in non-pathogenic Mycobacterium smegmatis, which does not possess PE_PGRS genes, confirmed its membrane localization. This protein was observed to have NADPH binding motif. Experimental validation confirmed its NADPH dependent oxido-reductase activity (Km value = 34.85 ± 9.478 μM, Vmax = 96.77 ± 7.184 nmol/min/mg of protein). Therefore, its potential to be targeted by first line anti-tubercular drug Isoniazid (INH) was investigated. INH was predicted to bind within the active site of PE_PGRS45 protein and experiments validated its inhibitory effect on the oxido-reductase activity of PE_PGRS45 with IC50/Ki values of 5.66 μM. Mtb is resistant to first line drugs including INH. Therefore, to address the problem of drug resistant TB, docking and Molecular Dynamics (MD) simulation studies between PE_PGRS45 and three drugs (Entacapone, Tolcapone and Verapamil) which are being used in Parkinson’s and hypertension treatment were performed. PE_PGRS45 bound the three drugs with similar or better affinity in comparison to INH. Additionally, INH and these drugs bound within the same active site of PE_PGRS45. This study discovered Mtb’s PE_PGRS45 protein to have an oxido-reductase activity and could be targeted by drugs that can be repurposed for TB treatment. Furthermore, in-vitro and in-vivo validation will aid in drug-resistant TB treatment. HIGHLIGHTS In-silico and in-vitro studies of hypothetical protein PE_PGRS45 (Rv2615c) of Mycobacterium tuberculosis (Mtb) reveals it to be an integral membrane protein PE_PGRS45 protein has substrate specificity for fatty acyl Coenzyme A (fatty acyl CoA) and possess NADPH dependent oxido-reductase activity Docking and simulation studies revealed that first line anti-tubercular drug Isoniazid (INH) and other drugs with anti-TB property have strong affinity for PE_PGRS45 protein Oxido-reductase activity of PE_PGRS45 protein is inhibited by INH PE_PGRS45 protein could be targeted by drugs that can be repurposed for TB treatment Communicated by Ramaswamy H. Sarma

STUDY OF RESISTANCE TO FIRST-LINE DRUGS IN MULTIDRUG RESISTANCE TUBERCULOSIS SUSPECTS FROM SPUTUM SAMPLES BY GOLD STANDARD – STANDARD ECONOMIC VARIANT 1% PROPORTION METHOD IN NORTH COASTAL ANDHRA PRADESH

Objectives: The objectives of the study were to culture Mycobacterium tuberculosis from sputum samples of multidrug resistance (MDR) suspects on Lowenstein-Jensen (LJ) media, to test for susceptibility and resistance to first-line antitubercular drugs rifampicin (RMP), isoniazid (INH), streptomycin (SM), and ethambutol (EMB) by conventional DST on LJ media by standard economic variant proportion (1%) method and to calculate the rate of MDR and pattern of drug resistance in MDR tuberculosis (MDR-TB) suspects. Methods: A prospective, laboratory-based study was done on a total of 80 samples from cases of suspected pulmonary and extra-pulmonary TB. Identification of culture isolates as M. tuberculosis was done by susceptibility to p-nitrobenzoic acid (PNB), niacin test, and catalase activity at 68°C/pH 7. Drug sensitivity testing (DST) of M. tuberculosis cultures on LJ medium for drugs was performed by a standard economic variant of the 1% proportion method. Results: Among MDR suspects, the maximum is in the age group of 45–60 years (35%) with a mean age of 42.75±15.93 years. The sex ratio of male to female is 2:1. Out of 80 samples, 36 samples (45%) were graded 1+, 31 samples (38.7%) 2+, and 13 samples (16.3%) 3+. All 80 sputum samples showed growth on LJ media within 8 weeks. When colonies obtained on LJ medium were subjected to biochemical tests for identification, all were positive for M. tuberculosis. Out of 80 M. tuberculosis isolates tested for sensitivity against first-line drugs (except pyrazinamide), 45 (56.3%) were found to be sensitive to all four drugs (INH, RMP, EMB, and SM), and 35 (43.7%) were resistant to at least one drug. Nine isolates (11.3%) showed resistance to a single drug (monoresistance). The various MDR patterns were INH+RMP seen in 6 strains (7.5%) and INH+RMP+SM seen in 4 strains (5%). Conclusion: Drug resistance trends must be closely monitored to evaluate the efficiency of existing therapies and their effect on pulmonary tuberculosis epidemic. To design the new drug regulations, more extensive data on drug sensitivity with standardized testing protocols which is quality assured are required.

Efficacy and Mode of Action of a Direct Inhibitor of Mycobacterium abscessus InhA.

There is an unmet medical need for effective treatments against Mycobacterium abscessus pulmonary infections, to which cystic fibrosis (CF) patients are particularly vulnerable. Recent studies showed that the antitubercular drug isoniazid is inactive against M.abscessus due to the incapacity of the catalase-peroxidase to convert the pro-drug into a reactive metabolite that inhibits the enoyl-ACP reductase InhA. To validate InhAMAB as a druggable target in M.abscessus, we assayed the activity of NITD-916, a 4-hydroxy-2-pyridone lead candidate initially described as a direct inhibitor of InhA that bypasses KatG bioactivation in Mycobacterium tuberculosis. The compound displayed low MIC values against rough and smooth clinical isolates in vitro and significantly reduced the bacterial burden inside human macrophages. Moreover, treatment with NITD-916 reduced the number and size of intracellular mycobacterial cords, regarded as markers of the severity of the infection. Importantly, NITD-916 significantly lowered the M.abscessus burden in CF-derived lung airway organoids. From a mechanistic perspective, NITD-916 abrogated de novo synthesis of mycolic acids and NITD-916-resistant spontaneous mutants harbored point mutations in InhAMAB at residue 96. That NITD-916 targets InhAMAB directly without activation requirements was confirmed genetically and by resolving the crystal structure of the protein in complex with NADH and NITD-916. These findings collectively indicate that InhAMAB is an attractive target to be exploited for future chemotherapeutic developments against this difficult-to-treat mycobacterium and highlight the potential of NITD-916 derivatives for further evaluation in preclinical settings.

Mechanistic studies on the oxidation reaction of antitubercular drug isoniazid and its analogy hydrazides by chlorine dioxide over a wide pH range

Oxidations of the antitubercular drug isoniazid (INH) and its analogy hydrazides, nicotinic hydrazide (NH), picolinoyl hydrazide (PH), and benzohydrazide (BH), by ClO2 were investigated with a focus on the kinetics and reaction mechanisms. In buffered solutions of a wide pH range (from 0.51 to 10.35), the oxidation reactions strictly followed the second-order kinetics, and the apparent second-order rate constant kapp versus pH profiles were established at 25.0 °C and 1.0 M ionic strength. Excess ClO2 could rapidly oxidize the hydrazides to their corresponding aryl acids which were identified by mass spectrometry. For each of the hydrazides, the proposed reaction mechanism involves parallel rate-determining reactions between ClO2 and various protolysis species of the hydrazide, rendering two types of hydrazyl free radicals; the free radicals are quickly oxidized by 3 more equivalents of ClO2 to aryl acids. The derived rate constants for the rate-determining reactions revealed that for each hydrazide a huge reactivity difference existed among the protolysis species (>108 times) and that the enolate form (or its resonant structures) was extremely reactive. Two possible modes of electron transfer in the rate-determining reactions are discussed based on the observed reaction characters. In buffered solution of pH 7.0 and 25.0 °C, the measured values of kapp are 6.20×104, 7.8×103, 2.57×103, and 1.83×103 M−1 s−1 for INH, NH, PH, and BH, respectively, imparting an important data set as a reference to the water treatment. This work may open a new door for resolving water pollution caused by INH and its derivatives.

Synthesis of new N-(3-oxo-1-thia-4-azaspiro[4.5]decan-4-yl)pyridine-3-carboxamide derivatives and evaluation of their anti-influenza virus and antitubercular activities.

We here report the synthesis, structural characterization, and evaluation of the antiviral and antitubercular activities of a novel series of hybrid spirothiazolidinone derivatives (2a-f and 3a-f) containing the nicotinohydrazide moiety, which is an isomer form of the approved antitubercular drug isoniazid. When evaluated for activity against influenza A/H1N1, A/H3N2, and B viruses, three of the new compounds proved to possess specific antiviral activity against the influenza A/H3N2 virus. The most active analog 3a, bearing a 2,8-dimethyl group at the spiro ring, displayed an antiviral EC50 value of 5.2 µM. Compound 3a produced no cytotoxicity at 100 µM, the highest concentration tested, giving a selectivity index of at least 19. Structure-activity relationship analysis indicated that the absence of the methyl substituent at the 2-position and the presence of a bulky substituent at the 8-position of the spirothiazolidinone system caused a significant decrease in antiviral activity. The in vitro antitubercular activity of compounds 2a-f and 3a-f was determined for six different drug-sensitive/drug-resistant laboratory strains and clinical isolates of Mycobacterium tuberculosis. Compounds 2c, 2d, 3b, 3c, and 3d showed weak antitubercular activity against different strains, with MIC values of 125-250 μM.

Comparative study on hepatoprotective activity of Pongamia pinnata (PP) & Annona squamosa (AS) leaf extracts against anti-tubercular drugs (isoniazid & rifampin) induced hepatotoxicity in rats

Objectives: - The goal of this study is to compare the effects of Pongamia Pinnata and Annona Squamosa on anti-tubercular medicines-induced hepatotoxicity in rats. Materials and Procedures: - In rats, hepatotoxicity was caused by administering a suspension of isoniazid and rifampin orally for 21 days. Pongamia Pinnata and Annona Squamosa, as well as anti-tubercular medicines, were given to the treatment groups. Biochemical & histological criteria were used to measure liver destruction. Results: - The use of Pongamia Pinnata and Annona Squamosa in combination with anti-tubercular medicines dramatically reduced Serum Glutamate Pyruvic Transaminase (SGPT), Serum Glutamate Oxaloacetic Transaminase (SGOT)& tissue malondialdehyde (MDA) levels. Inflammation, degeneration, and necrotic alterations in hepatocytes were reduced. Pongamia Pinnata also reduced a drop in blood Superoxide Dismutase (SOD) when compared to a control group getting only anti-tubercular medicines. Pongamia Pinnata, on the other hand, had no statistically significant effects when compared to Annona Squamosa and silymarin. Conclusion: - Annona Squamosa was found to be an effective hepatoprotective agent in rats, as it considerably reduced the hepatotoxic damage caused by anti-tubercular medicines. However, when the effects of Pongamia Pinnata & Annona Squamosa or silymarin were compared, there was no statistically significant difference.

Відмінності в імунологічному статусі хворих на туберкульоз легень при розвитку алергічних та токсико-алергічних побічних реакцій при лікуванні протитуберкульозними препаратами

Abstract. The aim of the study: to establish differences in the immunological status of patients with pulmonary tuberculosis (TB) in the development of allergic and toxico-allergic adverse reactions during treatment with anti-tuberculosis drugs. Materials and methods of research. An analysis of the examination data of 68 patients with pulmonary TB who underwent inpatient treatment at the State Organization «Yanovsky National Institute of Phthisiology and Pulmonology NAMS of Ukraine». The mean age of patients was (38.2 ± 1.8) years (19 to 76 years). At the beginning of inpatient treatment in the clinic all patients underwent a complex examination: clinical, radiological, laboratory (general blood and urine tests, with blood levels of bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), urea, creatinine, glucose), microbiological, immunological (determination of serum tryptase level, total IgE level, lymphocyte migration inhibition (LMI) reaction and assessment of erythrocyte sedimentation rate (ERS) to first-line antitubercular drugs (ATD) (rifampicin, isoniazid and ethambutol)). Conclusions. The study revealed a significant difference between a number of immunological parameters in patients with pulmonary TB in the development of allergic and toxic-allergic reactions to ATD. The presence of clinical signs of allergy to ATD in patients with TB causes the formation of: elevated serum levels of tryptase and IgE, which indicates the activation of mast cells and basophils under the influence of ATD; significantly higher frequency of positive reactions of ERS (to isoniazid and ethambutol) and LMI (to isoniazid) — which reflects the state of sensitization to ATD. The immune status of patients with TB with allergic manifestations to ATD (without toxic reactions) differs from that in patients with toxic-allergic reactions with more pronounced laboratory signs of immediate hypersensitivity reactions to ATD. Immunological reactions in patients with TB with toxic-allergic reactions have a number of differences that are not typical for patients of group 1 with allergies: significantly lower lymphocyte sensitization in patients with ATD (only to isoniazid in LIM), lack of correlation of IgE serum levels with tryptase levels — indicating the genesis of other mechanisms of hypersensitivity to ATD (possibly pseudoallergic) in such patients. The formation of toxic-allergic manifestations of intolerance to ATD is influenced mainly by liver dysfunction, which indicates a leading toxic effect of ATD in such patients. Key words: allergic reactions, immunological parameters, cellular hypersensitivity, anti-tuberculosis drugs, toxic-allergic reactions, pulmonary tuberculosis

Hepatoprotective Activity of Pongamia Pinnata Leaves on Antitubercular Drugs (Isoniazid & Rifampin) Induced Hepatotoxicity in Rats

Hepatoprotective effect of an ethanolic extract of Pongamia Pinnata on antitubercular drugs (isoniazid and rifampin) induced hepatotoxicity in rats.
 Methods: The experiment used five groups of male wistar rats, each with six individuals. The two control groups were given gum acacia and a mixture of isoniazid and rifampin. The two test groups received 200 and 400 mg/kg of an ethanolic extract of the leaves of Pongamia Pinnata, respectively. The fifth group was given silymarin (50mg/kg, orally). The concentrations of serum Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline Phosphatase (ALP), tissue Malondialdehyde (MDA) & thiols were calculated. One-way ANOVA was used for statistical examination, monitored through Tukey's test.
 Results: When rats were given a mixture of antitubercular drugs and a high dosage (400 mg/kg) of an ethanolic extract of Pongamia Pinnata, blood enzyme levels were lower than when they were given antitubercular drugs alone. The co-administration of a high dose of Pongamia Pinnata extract with antitubercular drugs reduced MDA levels and elevated thiol levels considerably (p˂ 0.05). These biochemical marker levels, however, were not adjusted.
 Conclusion: In rats, Pongamia Pinnata encompasses a partial protective effect against the hepatotoxicity caused by antitubercular drugs at high doses.

Design and Synthesis of Highly Active Antimycobacterial Mutual Esters of 2-(2-Isonicotinoylhydrazineylidene)propanoic Acid.

The combination of two active scaffolds into one molecule represents a proven approach in drug design to overcome microbial drug resistance. We designed and synthesized more lipophilic esters of 2-(2-isonicotinoylhydrazineylidene)propanoic acid, obtained from antitubercular drug isoniazid, with various alcohols, phenols and thiols, including several drugs, using carbodiimide-mediated coupling. Nineteen new esters were evaluated as potential antimycobacterial agents against drug-sensitive Mycobacterium tuberculosis (Mtb.) H37Rv, Mycobacterium avium and Mycobacterium kansasii. Selected derivatives were also tested for inhibition of multidrug-resistant (MDR) Mtb., and their mechanism of action was investigated. The esters exhibited high activity against Mtb. (minimum inhibitory concentrations, MIC, from ≤0.125 μM), M. kansasii, M. avium as well as MDR strains (MIC from 0.25, 32 and 8 µM, respectively). The most active mutual derivatives were derived from 4-chloro/phenoxy-phenols, triclosan, quinolin-8-ol, naphthols and terpene alcohols. The experiments identified enoyl-acyl carrier protein reductase (InhA), and thus mycobacterial cell wall biosynthesis, as the main target of the molecules that are activated by KatG, but for some compounds can also be expected adjunctive mechanism(s). Generally, the mutual esters have also avoided cytotoxicity and are promising hits for the discovery of antimycobacterial drugs with improved properties compared to parent isoniazid.

3D-Printed Porous Tantalum Coated with Antitubercular Drugs Achieving Antibacterial Properties and Good Biocompatibility.

Treatment of bone and joint tuberculosis remains a challenge. The development of tissue-engineered drug-loaded biomaterials has increased the therapeutic options. However, for the treatment of osteoarticular tuberculosis with severe local infection risks and high weight-bearing requirements, it is still necessary to design materials consistent with bone biomechanics, cytocompatibility, and osteogenesis and to provide more effective antimicrobial functions. The antitubercular drugs isoniazid and rifampicin are loaded with gellan gum, and a 3D-printed porous tantalum surface is treated with polydopamine to increase adhesion. The osteogenic induction and differentiation are tested using alkaline phosphatase, alizarin red staining, sirius red staining, and polymerase chain reaction testing. Bone regeneration in vivo is measured by X-ray, micro-computerized tomography, hard tissue sections, and fluorescence staining. The drug is released slowly in vitro and in vivo, increasing the duration of antibacterial action. The composite bio-scaffolds inhibit Staphylococcus aureus growth, have good biocompatibility, and does not inhibit the induction of osteogenic differentiation of rat bone marrow mesenchymal stem cells. The composite bio-scaffold can simultaneously achieve localized long-term controlled drug release and bone regeneration and is a promising route for bone and joint tuberculosis treatment.

In vitro anti-Toxoplasma gondii efficacy of synthesised benzyltriazole derivatives.

Toxoplasma gondii, an obligate intracellular parasite, is the aetiological agent of toxoplasmosis, a disease that affects approximately 25% – 30% of the world’s population. At present, no safe and effective vaccine exists for the prevention of toxoplasmosis. Current treatment options for toxoplasmosis are active only against tachyzoites and may also cause bone marrow toxicity. To contribute to the global search for novel agents for the treatment of toxoplasmosis, we herein report the in vitro activities of previously synthesised benzyltriazole derivatives. The effects of these compounds against T. gondii in vitro were evaluated by using a expressing green fluorescent protein (GFP) type I strain parasite (RH-GFP) and a type II cyst-forming strain of parasite (PruΔku80Δhxgprt). The frontline antitubercular drug isoniazid, designated as Frans J. Smit -isoniazid (FJS-INH), was also included in the screening as a preliminary test in view of future repurposing of this agent. Of the compounds screened, FJS-302, FJS-303, FJS-403 and FJS-INH demonstrated > 80% parasite growth inhibition with IC50 values of 5.6 µg/mL, 6.8 µg/µL, 7.0 µg/mL and 19.8 µg/mL, respectively. FJS-302, FJS-303 and FJS-403 inhibited parasite invasion and replication, whereas, sulphadiazine (SFZ), the positive control, was only effective against parasite replication. In addition, SFZ induced bradyzoite differentiation in vitro, whilst FJS-302, FJS-303 and FJS-403 did not increase the bradyzoite number. These results indicate that FJS-302, FJS-303 and FJS-403 have the potential to act as a viable source of antiparasitic therapeutic agents.

Zinc and Sulfur Codoped Iron Oxide Nanocubes Anchored on Carbon Nanotubes for the Detection of Antitubercular Drug Isoniazid

Zinc and sulfur codoped iron oxide nanocubes on functionalized multiwalled carbon nanotubes (Zn@S-FeNC/f-CNTs) were synthesized by a conventional hydrothermal (HT) route followed by ultrasonication...

Cytocompatibility and cellular interactions of chondroitin sulfate microparticles designed for inhaled tuberculosis treatment

Tuberculosis remains a leading cause of death, therapeutic failure being mainly due to non-compliance with prolonged treatments, often associated with severe side-effects. New therapeutic strategies are demanded and, considering that the lung is the primary site of infection, direct lung delivery of antibiotics is possibly an effective approach. Therapeutic success in this context depends on suitable carriers that reach the alveoli where Mycobacterium hosts (macrophages) reside, as well as on their ability to promote macrophage capture and intracellular accumulation of drugs. In this work, we propose inhalable polymeric microparticles produced from chondroitin sulfate, a polymer composed by moieties recognized by macrophage receptors. Spray-drying of chondroitin sulfate in combination with two first-line antitubercular drugs (isoniazid and rifabutin) yielded respirable microparticles that evidenced no cytotoxic effects on lung epithelial cells (A549) and macrophages (dTHP1 and J744A.1). The microparticles exhibited tendency for macrophage capture in a dose-dependent manner, which was validated through imaging. High content image analysis revealed that rifabutin induced a dose-dependent increase in phospholipid content of macrophages, which could be prevented by formulation in chondroitin sulfate microparticles. This work provides indications on the potential of chondroitin sulfate carriers to interact with macrophages, thus providing a platform for drug delivery in the context of macrophage intracellular diseases, namely tuberculosis.