Mariana Meckes-Fischer

Ursolic and oleanolic acids as antimicrobial and immunomodulatory compounds for tuberculosis treatment

BackgroundNew alternatives for the treatment of Tuberculosis (TB) are urgently needed and medicinal plants represent a potential option. Chamaedora tepejilote and Lantana hispida are medicinal plants from Mexico and their hexanic extracts have shown antimycobacterial activity. Bioguided investigation of these extracts showed that the active compounds were ursolic acid (UA) and oleanolic acid (OA).MethodsThe activity of UA and OA against Mycobacterium tuberculosis H37Rv, four monoresistant strains, and two drug-resistant clinical isolates were determined by MABA test. The intracellular activity of UA and OA against M. tuberculosis H37Rv and a MDR clinical isolate were evaluated in a macrophage cell line. Finally, the antitubercular activity of UA and OA was tested in BALB/c mice infected with M. tuberculosis H37Rv or a MDR strain, by determining pulmonary bacilli loads, tissue damage by automated histomorphometry, and expression of IFN-γ, TNF-α, and iNOS by quantitative RT-PCR.ResultsThe in vitro assay showed that the UA/OA mixture has synergistic activity. The intracellular activity of these compounds against M. tuberculosis H37Rv and a MDR clinical isolate in a macrophage cell line showed that both compounds, alone and in combination, were active against intracellular mycobacteria even at low doses. Moreover, when both compounds were used to treat BALB/c mice with TB induced by H37Rv or MDR bacilli, a significant reduction of bacterial loads and pneumonia were observed compared to the control. Interestingly, animals treated with UA and OA showed a higher expression of IFN-γ and TNF-α in their lungs, than control animals.ConclusionUA and OA showed antimicrobial activity plus an immune-stimulatory effect that permitted the control of experimental pulmonary TB.

Antitubercular Activity and the Subacute Toxicity of (−)-Licarin A in BALB/c Mice: A Neolignan Isolated from Aristolochia taliscana

BACKGROUND AND AIMS Tuberculosis remains a worldwide health problem and requires long-term treatment with several antibiotics; therefore, compliance problems and the emergence of multidrug resistance (MDR) are involved. (-)-Licarin A (LA) was isolated from diverse plants such as Aristolochia taliscana and possesses antimycobacterial, antiinflammatory, trypanocidal, and neuroprotective activities. The aim of the study was to determine the antitubercular and subacute toxicity of LA isolated from A. taliscana in BALB/c mice. METHODS The antitubercular activity of LA was tested in a TB murine model inducing disease with M. tuberculosis H37Rv or MDR. Mice were treated with LA (5 mg/kg) for 30 and 60 days; post/treatment, lung bacilli loads and pneumonia percentage were determined. The subacute toxicity of LA (21 days) was evaluated in healthy mice. After treatment, biochemical and hematological parameters were determined and main organs were analyzed histologically. RESULTS In animals infected with drug-sensitive or MDR strains, LA produced a significant decrease of pulmonary bacillary burdens at day 30 of treatment, and a significant pneumonia reduction at days 30 and 60 of treatment. Regarding subacute toxicity, LA administration during 21 days showed no abnormalities in main-organ macro- and microarchitecture. Biochemical and hematological parameters analyzed showed no statistical differences between control and treated groups. CONCLUSIONS (-)-Licarin A reduces pneumonia of mice infected with both mycobacterium strains. Also, subacute toxicity of LA exhibits no major signs of damage. Biochemical and hematological parameters and histological analyses indicate that LA caused no significant changes at the doses assayed.

Medical plant extracts and natural compounds with a hepatoprotective effect against damage caused by antitubercular drugs: A review

Drug-induced liver injury encompasses a spectrum of diseases ranging from mild biochemical abnormalities to acute liver failure; example of this scenery is hepatotoxicity caused by the first-line antituberculous drugs isoniazid, rifampin and pyrazinamide, which are basic for treatment of drug-sensible and drug-resistant tuberculosis. In the search for pharmacological alternatives to prevent liver damage, antitubercular drugs have been the subject of numerous studies and published reviews, a great majority of them carried out by Asian countries. At the same time, hepatoprotectors from plant source are now emerging as a possible alternative to counteract the toxic effects of these therapeutic agents. The present review aims to highlight the most recent studies on the subject, based information published in scientific databases such as Scopus and PubMed.

Microbiological and Pharmacological Evaluation of the Micropropagated Rubus liebmannii Medicinal Plant

Rubus liebmannii is an endemic species from Mexico used in traditional medicine primarily to treat dysentery and cough. The in vitro activity against Giardia lamblia and Entamoeba histolytica that produces the ethanolic extract of the aerial parts of the plant led us to expand the pharmacological and phytochemical research of this species. Gastrointestinal disorders including amebiasis remain one of the health problems that need to be addressed and it is of interest to find alternatives that improve their treatment. Also, it is important to emphasize that R. liebmannii grows wild in the country and is not found in abundance; therefore, alternatives that avoid overexploitation of the natural resource are mandatory. Ongoing with the evaluation of the potentialities that R. liebmannii possesses for treating infectious gastrointestinal diseases, the aim of the present study was to evaluate the biological effects and the chemical composition of the micropropagated plant.

Sphaeralcic acid and tomentin, anti-inflammatory compounds produced in cell suspension cultures of Sphaeralcea angustifolia.

Sphaeralcea angustifolia, an endangered plant species in Mexico, is employed to treat inflammatory processes and as a wound healing remedy. Scopoletin (1) was reported as one of the main bioactive compounds in this plant. Here, we isolated and identified compounds with anti-inflammatory properties from the suspension-cultured cells of S. angustifolia. The CH2Cl2 : CH3OH extract of the cells exhibited anti-inflammatory properties in acute inflammation models. Two compounds were isolated, 5-hydroxy-6,7-dimethoxycoumarin, named tomentin (2), and 2-(1,8-dihydroxy-4-isopropyl-6-methyl-7-methoxy)-naphthoic acid, denominated as sphaeralcic acid (3). Their structures were determined by spectroscopic and spectrometric analyses. The anti-inflammatory effects of both compounds were also evaluated. At a dose of 45 mg/kg, compound 2 inhibited the formation of λ-carrageenan footpad edema at 58 %, and compound 3 at 66 %. Local application of compound 2 (225 mM per ear) or 3 (174 mM per ear) inhibited the phorbol ester-induced auricular edema formation by 57 % or 86 %, respectively. The effect of compound 3 was dose-dependent and the ED50 was 93 mM.