Luis R. Hernández

Antimicrobial, anti-inflammatory, antiparasitic, and cytotoxic activities of Galium mexicanum

ETHNOPHARMACOLOGICAL RELEVANCE To study the potential benefit of the traditional Mexican medicinal plant Galium mexicanum Kunth (Rubiaceae). Hexane, chloroform, and methanol extracts as well as various fractions from these extracts were tested to determine antibacterial, antifungal, antiparasitic or anti-inflammatory activities in vitro. MATERIALS AND METHODS Aerial parts of the plant were extracted with various solvents and fractionated accordingly. Their antibacterial and antifungal activities were assessed on nine bacterial and four fungal strains. Leishmania donovani was used as a protozoan strain for antiparasitic activity. The anti-inflammatory activity of the compounds was investigated by measuring the secretion of interleukin-6 when macrophages were exposed to lipopolysaccharide. RESULTS Various extracts and fractions obtained from this plant exhibit antibacterial, antifungal, antiparasitic, and anti-inflammatory activities. Of special interest was the hexane fraction HE 14 b, which show antibacterial (ranging between 67 and 666 μg/ml) and antifungal (at concentrations of 333 μg/ml) activities. Also the hexane fraction HE 5 exhibited antiparasitic activity (at concentrations of 260 μg/ml), whereas the methanol fraction ME 13-15 showed a potent anti-inflammatory activity when compared to dexamethasone. Chemical analyses of the chloroform extract show the presence of triterpenes, saponins, flavonoids, sesquiterpene lactones, and glucosides, but no tannins were detected in the assayed extract. CONCLUSIONS The benefit of Galium mexicanum as a traditional medicinal plant was confirmed using antibacterial and antifungal assays in vitro. We also report for the first time, and to the best of our knowledge, antiparasitic and anti-inflammatory activities of this plant.

Antimicrobial activities of sesquiterpene lactones and inositol derivatives from Hymenoxys robusta.

Six compounds from the aerial parts of the Argentinean plant Hymenoxys robusta (Rusby) Parker were isolated and their structures elucidated using extensive spectroscopic analyses. These compounds comprise two inositol derivatives and four 3,4-seco-pseudoguaianolides, including vermeerin. Bioactivity assays of these compounds against bacterial and fungal pathogens showed that only vermeerin possessed antimicrobial activity specific against Staphylococcus aureus, and showed no toxicity when exposed to human-derived macrophages.

Antimicrobial, Antiparasitic, Anti-Inflammatory, and Cytotoxic Activities of Lopezia racemosa

The present study investigates the potential benefits of the Mexican medicinal plant Lopezia racemosa (Onagraceae). Extracts and fractions from aerial parts of this plant were assessed to determine their antibacterial, antifungal, antiparasitic, anti-inflammatory and cytotoxic activities in vitro. Aerial parts of the plant were extracted with various solvents and fractionated accordingly. Extracts and fractions were tested against a panel of nine bacterial and four fungal species. The antiparasitic activity was tested against Leishmania donovani, whereas the anti-inflammatory activity of the compounds was determined by measuring the secretion of interleukin-6 from human-derived macrophages. The same macrophage cell line was used to investigate the cytotoxicity of the compounds. Various extracts and fractions showed antibacterial, antifungal, antiparasitic, and anti-inflammatory activities. The hexanic fraction HF 11-14b was the most interesting fraction with antimicrobial, and anti-inflammatory activities. The benefit of L. racemosa as a traditional medicinal plant was confirmed as shown by its antibacterial, antifungal and anti-inflammatory activities. To the best of our knowledge, this is the first study reporting the biological activities of L. racemosa, including antiparasitic and anti-inflammatory activities.

Sesquiterpene lactones from Stevia breviaristata

Abstract Reinvestigation of Stevia breviaristata afforded, in addition to several known compounds, seven new sesquiterpene lactones: four guaianolides, two germacranolides and one eudesmanolide. The structures were established mainly by NMR spectroscopy.

Antimicrobial, Anti-Inflammatory, Antiparasitic, and Cytotoxic Activities of Laennecia confusa

The current paper investigated the potential benefit of the traditional Mexican medicinal plant Laennecia confusa (Cronquist) G. L. Nesom (Asteraceae). Fractions from the hexane, chloroform, methanol, and aqueous extracts were analyzed for antibacterial, antifungal, anti-inflammatory, and antiparasitic activities. The antimicrobial activity of the extracts and fractions was assessed on bacterial and fungal strains, in addition to the protozoa Leishmania donovani, using a microdilution assay. The propensity of the plants compounds to produce adverse effects on human health was also evaluated using propidium iodine to identify damage to human macrophages. The anti-inflammatory activity of the extracts and fractions was investigated by measuring the secretion of interleukin-6. Chemical analyses demonstrated the presence of flavonoids, cyanogenic and cardiotonic glycosides, saponins, sesquiterpene lactones, and triterpenes in the chloroform extract. A number of extracts and fractions show antibacterial activity. Of particular interest is antibacterial activity against Staphylococcus aureus and its relative methicillin-resistant strain, MRSA. Hexanic and chloroformic fractions also exhibit antifungal activity and two extracts and the fraction CE 2 antiparasitic activity against Leishmania donovani. All bioactive extracts and fractions assayed were also found to be cytotoxic to macrophages. In addition, the hexane and methane extracts show anti-inflammatory activity by suppressing the secretion of interleukine-6.

Sesquiterpene lactones from Stevia alpina var. glutinosa

Abstract The aerial parts of Stevia alpina var. glutinosa afforded, in addition to knownsesquiterpene lactones, two new germacranolides and two new eudesmanolides. The structureswere established mainly by NMR spectroscopy.

Toxicity evaluation of high-fluorescent rare-earth metal nanoparticles for bioimaging applications

Research on nanometer-sized luminescent semiconductors and their biological applications in detectors and contrasting agents is an emergent field in nanotechnology. When new nanosize technologies are developed for human health applications, their interaction with biological systems should be studied in depth. Rare-earth elements are used in medical and industrial applications, but their toxic effects are not known. In this work, the biological interaction between terbium-doped gadolinium oxysulfide nanoparticles (GOSNPs) with human peripheral blood mononuclear cells (PBMC), human-derived macrophages (THP-1), and human cervical carcinoma cell (HeLa) were evaluated. The GOSNPs were synthetized using a hydrothermal method to obtain monodisperse nanoparticles with an average size of 91 ± 9 nm. Characterization techniques showed the hexagonal phase of the Gd2 O2 S:Tb3+ free of impurities, and a strong green emission at λemi  = 544 nm produced by Tb3+ was observed. Toxic effects of GOSNPs were evaluated using cell viability, apoptosis, cell-cycle progression, and immunological response techniques. In addition, an Artemia model was used to assess the toxicity in vivo. Results indicated cell apoptosis in both types of cells with less sensitivity for PBMC cells compared to HeLa cells. In addition, no toxic effects were observed in the in vivo model of Artemia. Moreover, GOSNPs significantly reduced the activation and cell-cycle progression of PBMC and HeLa cells, respectively. Interestingly, an increase in proinflammatory cytokines was not observed. Our data suggest that fluorescence applications of GOSNPs for biolabeling are not toxic in primary immune cells and they may have an immunomodulatory effect.

Exploring the biological activities of Echeveria leucotricha

Echeveria leucotricha J. A. Purpus (Crassulaceae) was evaluated for its potential antibacterial, antifungal, antiparasitic, cytotoxic and anti-inflammatory bioactivities. Aerial parts were extracted with hexane, methanol and chloroform, and fractionated accordingly. Biological activity was assessed in vitro against five Gram-positive and four Gram-negative bacteria, four human pathogenic fungi and the protozoan Leishmania donovani. Extracts and fractions showing bioactivities were further investigated for their cytotoxic activities on macrophages. Results show that several extracts and fractions exhibited significant antibacterial, antifungal, and antiparasitic activities, but no anti-inflammatory activity was recorded. Here, we report for the first time, and to the best of our knowledge, these bioactivities, which suggest that this plant can be used in the traditional Mexican medicine.

13C NMR assignments and conformational evaluation of diterpenes from Croton sarcopetalus Muell.

The known diterpenes junceic acid (1) and the stress metabolite derivatives 2–4 were isolated from the hexane extracts of the roots of Croton sarcopetalus Muell. The complete 13C NMR chemical shift assignments of these compounds were achieved with the aid of DEPT and HETCOR experiments.

Protective antifungal activity of essential oils extracted from Buddleja perfoliata and Pelargonium graveolens against fungi isolated from stored grains.

The chemical composition and antifungal activity of essential oils extracted from Buddleja perfoliata and Pelargonium graveolens were analysed to assess their efficacy as a potential alternative to synthetic chemical fungicides to protect stored grain.