In Vitro Potential of the Acetone Leaf Extract and Fractions of Psychotria capensis (Eckl.) Vatke (Rubiaceae) to Combat Co-Infection of Tuberculosis and Helminthiasis

Tuberculosis (TB) is a disease of global importance that affects millions of people. Approximately a quarter of the world’s population is currently infected with M. tuberculosis, and about 10% of those infected will develop into active disease, particularly immune compromised individuals. Helminthiasis is of global health importance, affecting over 2 billion people mostly in resource-poor countries. Co-infection with tuberculosis (TB) and helminths (worms) is an emerging global public health concern with both affecting about one-third of the global population. Chronic infection with helminths can result in impaired immune responses to TB as well as enhancing failure to TB therapy and BCG vaccination. Antimycobacterial and anthelmintic activities of the acetone extract and fractions of Psychotria capensis were evaluated, including their in vitro safety. In addition, the anti-inflammatory and immunomodulatory effect of the fractions and crude extract of P. capensis were assessed. Antimycobacterial activity of the extract and fractions was tested against four non-tuberculous mycobacteria (Mycobacterium smegmatis, M. fortuitum, M. aurum, M. bovis BCG) and pathogenic M. tuberculosis H37Rv while the Egg Hatch Assay (EHA) was used for the anthelmintic test on eggs of Haemonchus contortus. Cytotoxicity was determined against Vero kidney cells while in vitro immune modulation via cytokine production was determined on activated macrophages. The minimum inhibitory concentration (MIC) values of the Psychotria capensis acetone extract and fractions ranged from 39 to 1,250 μg/ml with the crude extract and hexane fraction having the best MIC values (both 39 μg/ml). In the EHA, the inhibitory concentration (IC50) ranged from 160 to 630 μg/ml with the hexane fraction having the best activity. The hexane and chloroform fractions were relatively non-toxic with LC50 values of 290 and 248 μg/ml respectively, while the acetone crude extract (64 μg/ml) and n-butanol fraction (71 μg/ml) were moderately toxic. The SI values (LC50/MIC) ranged from 0.1 to 7.4 with the hexane fraction having the highest value against M. smegmatis (7.4). The hexane fraction had the best dual anthelmintic and antimycobacterial activity. This fraction had the best NO inhibitory activity and was the least cytotoxic, indicating that its activity was not due to general metabolic toxicity, with 96.54% cell viability. Pro-inflammatory cytokines such as IL-12p70 were upregulated while IL-10 expression was inhibited by the extracts. Compounds were detected using GC-MS analysis, and in both the crude acetone extract and the hexane fraction was the diterpene neophytadiene, which has anti-inflammatory and antimicrobial activity. Finding alternative or complementary approaches to dealing with TB infections by, amongst other things, reducing the incidence of helminth infestations may lessen the burden of TB, contributing to slowing the spread of multi-drug resistance.

Uniformity and Efficacy of Dry Powders Delivered to the Lungs of a Mycobacterial-Surrogate Rat Model of Tuberculosis

Purpose Pulmonary administration of dry drug powder is a considered promising strategy in the treatment of various lung diseases such as tuberculosis and is more effective than systemic medication. However, in the pre-clinical study phase, there is a lack of devices for effective delivery of dry powders to the lungs of small rodents. In this study, an administration device which utilizes Venturi effect to deliver dry powders to the lungs homogeneously was developed. Methods A Venturi-effect administration device which synchronizes with breathes by use of a ventilator and aerosolizes the dry powders was created. Pulmonary distribution of inhalable dry powders prepared by spray-drying poly(lactic-co-glycolic) acid and an antituberculosis agent rifampicin and anti-tuberculosis effect of the powders on mycobacteria infected rats by administration with the Venturi-effect administration device and a conventional insufflation device were evaluated. Results Homogeneous distribution of the dry powders in the lung was achieved by the Venturi-effect administration device due to efficient and recurring aerosolization of loaded dry powders while synchronizing with breathes. Amount of rifampicin delivered to the lungs by the Venturi-effect administration device was three times higher than that by a conventional insufflation device, demonstrating three times greater antimycobacterial activity. Conclusions The Venturi-effect administration device aerosolized inhalable antituberculosis dry powders efficiently, achieved uniform pulmonary distribution, and aided the dry powders to exert antituberculosis activity on lung-residing mycobacteria.

Ethnobotanical plants used in the management of symptoms of tuberculosis in rural Uganda

Background Tuberculosis (TB) caused by Mycobacterium tuberculosis is the 13th leading cause of death worldwide. The emergence of multidrug-resistant TB (MDR-TB) poses a major health security threat. Plants have traditionally been used as a source of medicine, since olden days and 80% of the communities in Africa still rely on herbal medicines for their healthcare. In many parts of Uganda, some plants have shown ethno-pharmacological prospects for the treatment of TB, and yet they have not been fully researched. Aim This study aimed to document plant species used traditionally by the herbalists and non-herbalist communities of Kitgum and Pader districts for managing symptoms of TB. Methods An ethnobotanical study was carried out in 42 randomly selected villages in Kitgum and Pader districts between August 2020 and January 2021. Information was obtained by administering semi-structured questionnaires to 176 respondents identified by snowball and random sampling methods. Data were analysed and presented using descriptive statistics and Informant Consensus Factor (ICF). Results Overall, only 27% of the respondents were knowledgeable about plants used for managing symptoms of TB. Nine plant species belonging to six families (Mimosaceae, Apiaceae, Lamiaceae, Rutaceae, Loganiaceae and Rubiaceae) were used to manage symptoms of TB. The most representative family was Rutaceae with three species, followed by Rubiaceae (two species) and the rest of the families were represented by one species each. The most frequently recorded species were Steganotaenia araliacea Hochst. (8.5%), Gardenia ternifolia Schumach. & Thonn (6.8%) and Albizia adianthifolia (Schum.) W.Wight (6.8%). Most of the medicinal plants were trees, and roots (69%) were the most frequently plant part used, followed by the bark (16%) and leaves (15%). The most common method of preparation was by pounding and mixing concoction with water. The administration of the concoctions was mostly done orally. Conclusions The results established the existence of few medicinal plants for managing symptoms of TB among the Acholi communities which could be used in developing new, effective plant-based antimycobacterial drugs. The few plants mentioned might face conservation threats due to exploitations of the roots. Phytochemical and toxicological studies are recommended to identify active compounds responsible for antimycobacterial activity.

Novel 2-Nitroimidazole and imidazooxazole Derivatives and Their Activity Against Trypanosoma cruzi and Mycobacterium tuberculosis

Background: Tuberculosis (TB) is one of the top ten causes of death worldwide, while Chagas disease (CD) is the parasitic disease that kills the largest number of people in the Americas. TB is the leading cause of death for patients with AIDS; it kills 1.5 million people and causes 10 million new cases every year. The lack of newly developed chemotherapeutic agents and insufficient access to health care services for a diagnosis increase the incidence of multidrug-resistant TB (MDRTB) cases. Although CD was identified in 1909, the chronic stages of the disease still lack adequate treatment. Objective: The purpose of this work was to design and synthesize two new series of 2-nitroimidazole 5a-e and imidazooxazoles 6a-e with 1H-1,2,3-triazolil nucleus and evaluate their activities against Tc and Mycobacterium tuberculosis (Mtb). Methods: Two series of five compounds were synthesized in a 3 or 4-step route in moderated yields, and their structures were confirmed by NMR spectral data analyses. The in vitro antitrypanosomal evaluation of products was carried out in an intracellular model using L929 cell line infected with trypomastigotes and amastigote forms of Tc of β-galactosidase-transfected Tulahuen strain. Their antimycobacterial activity was evaluated against Mtb strain H37Rv. Results: In general, 2-nitroimidazolic derivatives proved to be more potent in regard to antitrypanocidal and antimycobacterial activity. The non-cytotoxic 2-nitroimidazole derivative 5b was the most promising with a half maximum inhibitory concentration of 3.2 µM against Tc and a minimum inhibitory concentration of 65.3 µM against Mtb. Conclusion: Our study reinforced the importance of 2-nitroimidazole and 1H-1,2,3-triazole nuclei in antimicrobial activity. In addition, derivative 5b proved to be the most promising, presenting important activity against Tc and Mtb and could be used as a starting point for the development of new agents against these diseases.

Synthesis of Antimycobacterial Agents that Harness Mycothiol and Cysteine conjugate β-lyase Metabolic Pathways

<p>Mycobacterium tuberculosis kills approximately two million people each year and is second only to HIV/AIDs in terms of death from infectious disease. The most pertinent problem in regards to Mycobacterium tuberculosis today is the increasing prevalence of drug resistant strains. Thus, there is a great need for the development of new drugs with novel targets. This thesis aimed to address this problem by synthesizing a compound that could exploit the mycothiol detoxification pathway, unique to Mycobacterium, in order to cause cell death, through the release of a harmful halothioketene. The research described herein involved the successful synthesis of the desired mycothiol analogue, along with three other related compounds. The target compounds were synthesised via protection of N-acetyl glucosamine, followed by thioglycosidation with cyclohexane thiol. Subsequent deprotection and coupling to Boc protected Strichlorovinyl cysteine provided access to the synthetic target and its β-anomer, as well as their Boc protected precursors. The original synthetic target demonstrated weak antimycobacterial activity against Mycobacterium smegmatis and an encouraging sub 100 μM MIC against Mycobacterium bovis derived Bacillus Calmette–Guérin. Unexpectedly the beta anomer of the synthetic target also displayed antimycobacterial activity against Bacillus Calmette–Guérin (MIC 125 - 250 μM). All compounds proved to be active against HL60 cells (16-114 μM). Whilst further work is required to improve efficacy, the work presented here demonstrates the potential of these compounds as leads for the generation of new antimycobacterial agents.</p>

Synthesis of Antimycobacterial Agents that Harness Mycothiol and Cysteine conjugate β-lyase Metabolic Pathways

<p>Mycobacterium tuberculosis kills approximately two million people each year and is second only to HIV/AIDs in terms of death from infectious disease. The most pertinent problem in regards to Mycobacterium tuberculosis today is the increasing prevalence of drug resistant strains. Thus, there is a great need for the development of new drugs with novel targets. This thesis aimed to address this problem by synthesizing a compound that could exploit the mycothiol detoxification pathway, unique to Mycobacterium, in order to cause cell death, through the release of a harmful halothioketene. The research described herein involved the successful synthesis of the desired mycothiol analogue, along with three other related compounds. The target compounds were synthesised via protection of N-acetyl glucosamine, followed by thioglycosidation with cyclohexane thiol. Subsequent deprotection and coupling to Boc protected Strichlorovinyl cysteine provided access to the synthetic target and its β-anomer, as well as their Boc protected precursors. The original synthetic target demonstrated weak antimycobacterial activity against Mycobacterium smegmatis and an encouraging sub 100 μM MIC against Mycobacterium bovis derived Bacillus Calmette–Guérin. Unexpectedly the beta anomer of the synthetic target also displayed antimycobacterial activity against Bacillus Calmette–Guérin (MIC 125 - 250 μM). All compounds proved to be active against HL60 cells (16-114 μM). Whilst further work is required to improve efficacy, the work presented here demonstrates the potential of these compounds as leads for the generation of new antimycobacterial agents.</p>

Antibacterial Effects of New Zealand Plant Extracts against Mycobacteria

<p>Mycobacterium tuberculosis, the causative agent of tuberculosis (TB) has infected approximately 1/3 of the world population, with 9.4 million new TB cases in 2008. In addition to increased cases of drug-resistant strains it is vital that novel antitubercular compounds are discovered in order to treat infections and reduce the time of current TB therapy courses. Natural resources such as plants are now being considered as the focus for discovering new compounds. Plants have long been investigated as a source of antibiotics for the treatment of human disease. New Zealand (NZ) contains a unique and diverse flora; however, to current knowledge no native plants have been examined for antimycobacterial activity. Using ethnobotany as a basis for selection, a total of 58 native plant samples were collected and tested for direct antimycobacterial activity. Samples were extracted with sterile distilled water (SDW), ethanol (EtOH) or methanol (MeOH) and screened for inhibition against the surrogate species, Mycobacterium smegmatis. Active plant samples were then validated for bacteriostatic activity towards M. bovis BCG and M. tuberculosis H37Ra as well as other clinically-important species. Nine extracts from the species Laurelia novae-zelandiae, Lophomyrtus bullata, Metrosideros excelsa, Myoporum laetum, Pittosporum tenuifolium, Pseudopanax crassifolius and Pseudowintera colorata were found to be active against M. smegmatis. Two active extracts were the bark and cambium extracts of Laurelia novae-zelandiae (Pukatea), which were reportedly used by indigenous Māori for the treatment of tubercular lesions. Upon further investigation these extracts also demonstrated bactericidal activity towards M. smegmatis as well as bacteriostatic activity towards the slow-growing species M. bovis BCG and M. tuberculosis. Purification techniques were then performed to improve the efficiency of activity and initial exploration of delivery systems was also examined. The bioactive extracts determined in this research offer a starting point for identifying their chemical basis of antimycobacterial activity with the objective of potentially discovering new anti-tubercular drugs.</p>

Antibacterial Effects of New Zealand Plant Extracts against Mycobacteria

<p>Mycobacterium tuberculosis, the causative agent of tuberculosis (TB) has infected approximately 1/3 of the world population, with 9.4 million new TB cases in 2008. In addition to increased cases of drug-resistant strains it is vital that novel antitubercular compounds are discovered in order to treat infections and reduce the time of current TB therapy courses. Natural resources such as plants are now being considered as the focus for discovering new compounds. Plants have long been investigated as a source of antibiotics for the treatment of human disease. New Zealand (NZ) contains a unique and diverse flora; however, to current knowledge no native plants have been examined for antimycobacterial activity. Using ethnobotany as a basis for selection, a total of 58 native plant samples were collected and tested for direct antimycobacterial activity. Samples were extracted with sterile distilled water (SDW), ethanol (EtOH) or methanol (MeOH) and screened for inhibition against the surrogate species, Mycobacterium smegmatis. Active plant samples were then validated for bacteriostatic activity towards M. bovis BCG and M. tuberculosis H37Ra as well as other clinically-important species. Nine extracts from the species Laurelia novae-zelandiae, Lophomyrtus bullata, Metrosideros excelsa, Myoporum laetum, Pittosporum tenuifolium, Pseudopanax crassifolius and Pseudowintera colorata were found to be active against M. smegmatis. Two active extracts were the bark and cambium extracts of Laurelia novae-zelandiae (Pukatea), which were reportedly used by indigenous Māori for the treatment of tubercular lesions. Upon further investigation these extracts also demonstrated bactericidal activity towards M. smegmatis as well as bacteriostatic activity towards the slow-growing species M. bovis BCG and M. tuberculosis. Purification techniques were then performed to improve the efficiency of activity and initial exploration of delivery systems was also examined. The bioactive extracts determined in this research offer a starting point for identifying their chemical basis of antimycobacterial activity with the objective of potentially discovering new anti-tubercular drugs.</p>