Mariana Meckes's research while affiliated with Mexican Institute of Social Security and other places

We analyzed the antimycobacterial activity of the hexane extract of rhizomes from Aristolochia elegans. Some compounds of this extract were purified and tested against a group of drug-resistant Mycobacterium tuberculosis strains. We also evaluated their antiprotozoal activities. The hexane extract was active against M. tuberculosis H37Rv at a MIC = 100 μg mL(-1); the pure compounds eupomatenoid-1, fargesin, and (8R,8'R,9R)-cubebin were active against M. tuberculosis H37Rv (MIC = 50 μg mL(-1)), while fargesin presented activity against three monoresistant strains of M. tuberculosis H37Rv and a MDR clinical isolate of M. tuberculosis (MIC < 50 μg mL(-1)). Both the extract and eupomatenoid-1 were very active against E. histolytica and G. lamblia (IC(50) < 0.624 μg mL(-1)); in contrast, fargesin and (8R,8'R,9R)-cubebin were moderately active (IC(50) < 275 μg mL(-1)). In this context, two compounds responsible for the antimycobacterial presented by A. elegans are fargesin and cubebin, although others may exert this activity also. In addition to the antimycobacterial activity, the hexane extract has important activity against E. histolytica and G. lamblia, and eupomatenoid-1 is one of the compounds responsible for the antiparasite activity.

Tuberculosis (TB - Mycobacterium tuberculosis) is an ancient infectious disease that has appeared once again as a serious worldwide health problem and now comprises the second leading cause of death resulting from a single infection. The prevalence of multidrug resistance (MDR) TB is increasing and therapeutic options for treatment are not always accessible; in fact, some patients do not respond to the available drugs. Therefore, there is an urgent need to develop novel anti-TB agents. The aim of the present study was to screen extracts of Aristolochia taliscana, a plant used in traditional Mexican medicine to treat cough and snake bites, for antimycobacterial activity. The hexanic extract of A. taliscana was tested by microdilution alamar blue assay against Mycobacterium strains and bioguided fractionation led to the isolation of the neolignans licarin A, licarin B and eupomatenoid-7, all of which had antimycobacterial activity. Licarin A was the most active compound, with minimum inhibitory concentrations of 3.12-12.5 microg/mL against the following M. tuberculosis strains: H37Rv, four mono-resistant H37Rv variants and 12 clinical MDR isolates, as well as against five non-tuberculous mycobacteria (NTM) strains. In conclusion, licarin A represents a potentially active anti-TB agent to treat MDR M. tuberculosis and NTM strains.

Intestinal infectious diseases are among the top 10 causes of mortality in Mexico. Children under 5 years of age and adults over 65 years are the most affected; the incidence is greater in rural and indigenous communities. Traditional remedies based on medicinal plants are commonly used; however, the biological activity of many of them has been poorly studied. Thus, we evaluated the antimicrobial activity of the hexane, dichloromethane, ethyl acetate, and methanol extracts of aerial parts and roots of the Piqueria trinervia. Cav. (Asteraceae) plant used to treat diarrhea in Mexico. The extracts were tested in vitro. against 11 strains: Escherichia coli., E. coli. multidrug resistant (MDR), Salmonella typhi., Shigella boydii., Staphylococcus aureus., Staphylococcus epidermidis., Yersinia enterocolitica., Vibrio cholerae. not toxic, Bacillus subtilis., Enterobacter aerogenes., and Enterobacter agglomerans.. The hexane extract obtained from the thick roots was active against the 11 strains. The ethyl acetate extract from the thin roots was active against eight of the strains; poor activity was detected in dichloromethane and methanol extracts.

Abstract Activity-directed fractionation of the methanol extract of the aerial parts of Helianthemum glomeratum Lag. (Cistaceae) led to the isolation ofkaempferol and quercetin as the major amoebicidat compounds. The inactive compound tiliroside was also isolated.

As the Mycobacterium tuberculosis strains resistant to multiple drugs are increasing at an alarming rate, there is an urgent need for alternative anti-tuberculosis drugs. In a bioassay-guided search for antimycobacterial compounds obtained from higher plants, the study of the hexane extract from the aerial parts of Lantana hispida was performed and the biological activity of the plant products were tested against Mycobacterium tuberculosis H37Rv strain by microdilution alamar blue assay. Activity of the primary fractions led to the isolation of three pentacyclic triterpenoids with oleanane nucleous, together with beta-sitosterol. The molecular structures of the compounds were characterized as 3-acetoxy-22-(2'-methyl-2Z-butenyloxy)-12-oleanen-28-oic acid (1), 3-hydroxy-22 beta-(2'-methyl-2Z-butenoyloxy)-12-oleanen-28-oic acid (reduced lantadene A) (2) and oleanolic acid (3). MIC values for compounds 1 and 2 were 50 microg/ml, and for compound 3 the MIC=25 microg/ml.

Brickellia paniculata has been used as spasmolytic in Mexican traditional medicine. Xanthomicrol and 3alpha-angeloyloxy-2alpha-hydroxy-13,14Z-dehydrocativic acid (AAHDD) are two of the main leaf components with antispasmodic activity. However, their mechanism of action remains unknown. An in vitro comparative study between xanthomicrol and AAHDD on rat uterus precontracted by either KCl (60 mM) or oxytocin (10 mIU/ml) was carried out to investigate the mechanism of action of these compounds on smooth muscle. Relaxant effect was measured as median inhibitory concentration (IC(50)) and maximal effect as maximal relaxant response (R(max)). Xanthomicrol was significantly more potent than AAHDD in inhibiting contractions induced by KCl 60 mM, whereas AAHDD was more potent than xanthomicrol in inhibiting contractions induced by oxytocin 10 mIU/ml. These results suggest that xanthomicrol induces a greater blocking effect on voltage-operated calcium channels than on receptor-operated gates.

Lippia dulcis hexane and ethanol extracts were tested for its anti-inflammatory activity in several animal models. Hexane extract showed to be inactive, but the ethanol extract at doses of 400 mg/kg produced significant inhibition of carrageenan-induced paw oedema and reduced the weight of cotton pellet-induced granuloma, moreover, the topical application of 0.5 mg/ear of this extract inhibited the edema induced with TPA by 49.13%, an effect which is of less intensity than that produced by indomethacine at the same dose.

Due to the emergence of multi-drug resistant Mycobacterium tuberculosis strains, there is an urgent need to search for new antimycobacterial drugs. The present work describes the bioactivity-guided fractionation of Chamaedora tepejilote hexane extract which led to the isolation and the characterization of squalene, farnesol, methylic ester of hexadecanoic acid, beta-sitosterol and ursolic acid. Activity against Mycobacterium tuberculosis H37Rv, determined by radiorespirometric Bactec assay, showed ursolic acid, squalene and farnesol to produce a M. tuberculosis growth inhibition of 99% at a concentration of 100 microg/mL.

Hypothermic and cardiovascular activities of the methanol extract of Jacaranda mimosaefolia leaves were tested. To evaluate the hypotensive properties, anesthetized rats were used and temperature, blood pressure, and cardiac frequency were recorded. In addition, the in vitro effect produced by the extract on induced contraction with norepinephrine (NE) in rat aorta rings was evaluated. The extract produced a significant hypothermic effect with a maximum at 2 h, an effect which was accompanied by hypotension and low cardiac frequency, physiological conditions that were again re-established to the following 2 h. In isolated aorta preparations norepinephrine antagonistic effect was not correlated with the presence of Ca2+, pD2 for NE was modified by the extract, an effect that could explain a blockade of the adrenergic receptors.

The extracts obtained from 14 plants of the Mexican medicinal flora were assessed for anti-inflammatory activity by carrageenan-induced rat paw edema model. The i.p. administration of the extracts at a dose of 400 mg/kg produced a high reduction of edema with 70% of the plant extracts. Oenothera rosea methanol extract, Sphaeralcea angustifolia chloroform extract, Acaciafarnesiana, Larrea tridentata and Rubus coriifolius methanol extracts as well as the aqueous extract of Chamaedora tepejilote were demonstrated to be particularly active against the induced hind-paw edema. Moderate inhibition of edema formation was also demonstrated with the methanol extracts of Astianthus viminalis, Brickellia paniculata, C. tepejilote and Justicia spicigera.