In vitro activity of natural products against the trypomastigote form ofTrypanosoma cruzi

Metabolites from the leaf extract of Serjania yucatanensis with trypanocidal activity against Trypanosoma cruzi

The bioassay-guided phytochemical investigation of the leaf extract of Serjania yucatanensis, a woody climbing plant endemic to the Yucatan peninsula, led to the identification of a mixture of a triterpene [lup-20(29)-en-3-one] and an oxygenated sesquiterpene (β-caryophyllene oxide), as that responsible for the originally detected trypanocidal activity in the organic crude extract. Results showed that the mixture of lup-20(29)-en-3-one and β-caryophyllene oxide is active against trypomastigotes of Trypanosoma cruzi (IC(50) =80.3 μg/mL) and inhibits the egress of trypomastigotes from infected Vero cells (when tested at 100 μg/mL) without being cytotoxic.

Chemical Composition, Antifungal and Herbicidal Effects of Essential Oil Isolated from Chersodoma argentina (Asteraceae)

Analysis of the hydrodistilled essential oil of the aerial parts of Chersodoma argentina Cabrera by GC- MS and NMR spectroscopy revealed that over 80% consisted of monoterpene hydrocarbons such as α-thujene, α-pinene and β-pinene. Contact and headspace volatile exposure assays of the essential oil demonstrated antifungal activity against Sclerotinia sclerotiorum, Sclerotium rolfsii and Rhizoctonia solani with the contact assay showing greater activity than the headspace assay. Herbicidal activity was shown by reduced root growth of Allium porrum, Solanum lycopersicon and Sorghum halepense in both assays.

Trypanocidal and antifungal activities of p-hydroxyacetophenone derivatives from Calea uniflora (Heliantheae, Asteraceae)

The dichloromethane extract of underground parts of Calea uniflora (Heliantheae, Asteraceae) exhibited trypanocidal and antifungal activities. Four p-hydroxyacetophenone derivatives were isolated as the main compounds: 2-senecioyl-4-(hydroxyethyl)-phenol (1), 2-senecioyl-4-(angeloyloxy-ethyl)-phenol (2), and two new derivatives, 2-senecioyl-4-(methoxyethyl)-phenol (3) and 2-senecioyl-4-(pentadecanoyloxyethyl)-phenol (4). 1 and 4 were active towards Trypanosoma cruzi trypomastigotes, reducing their number by 70 and 71% at 500 μg mL−1, whereas 2 and 3 were inactive. All the compounds tested showed antifungal activity with minimal inhibitory concentration values between 500 and 1000 μg mL−1 against pathogenic Candida spp. and dermatophytes. The isolation, structure elucidation, NMR spectral assignments and bioactivity results of these compounds are reported.

Antimicrobial activity of selected plant species from "the Argentine Puna" against sensitive and multi-resistant bacteria

AIM

The plant species reported here are traditionally used in the "Puna" or "Altiplano" of Argentina for ailments related to bacterial infections. The aim of this study was to evaluate their antimicrobial properties against a panel of sensitive and multi-resistant gram-positive and gram-negative bacteria.

MATERIALS AND METHODS

The antimicrobial activity of tinctures and aqueous extracts (Baccharis boliviensis, Chiliotrichiopsis keidelii, Chuquiraga atacamensis, Fabiana bryoides, Fabiana densa, Fabiana punensis, Frankenia triandra, Parastrephia lucida, Parastrephia lepidophylla, Parastrephia phyliciformis, Tetraglochin cristatum) was determined using the agar macrodilution and broth microdilution methods recommended by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). The antibiotic resistant clinical strains were isolated from nosocomial infection in human lesions of skin and soft parts.

RESULTS

The ethanolic extracts of 11 plant species inhibited the growth of one or more of the following strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Morganella morganii, Pseudomonas aeruginosa. Ethanol extracts (tinctures) of aerial parts of Baccharis, Fabiana and Parastrephia showed the highest levels of antibacterial activity on methicillin, oxacillin and gentamicin resistant Staphylococcus with MIC values from 20 to 150 microg/ml. Baccharis boliviensis and Fabiana bryoides were more active than the other plant species on Enterococcus faecalis with different phenotype. The most interesting activity on multi-resistant gram-negative strains was obtained from Chuquiraga atacamensis. Parastrephia species showed activity against Enterobacter cloacae, Pseudomonas aeruginosa and Proteus mirabilis. The ethanolic extracts exhibited stronger activity and broader spectrum of action than aqueous extracts. The extracts were bactericidal in most cases.

CONCLUSIONS

The presence of antibacterial activity in Puna plant extracts against multi-resistant bacteria give support to their traditional use for treating conditions associated with microorganisms in humans and animals and consequently seems promising for the treatment of multi-resistant bacteria.

Diterpenoids from Azorella compacta (Umbelliferae) active on Trypanosoma cruzi

The anti-Trypanosoma cruzi activity of natural products isolated from Azorella compacta was evaluated, with particular emphasis on their effect against intracellular amastigotes. Five diterpenoids from A. compacta derived from mulinane and azorellane were isolated and identified. Only two products, named azorellanol (Y-2) and mulin-11,3-dien-20-oic acid (Y-5), showed trypanocidal activity against all stages of T. cruzi including intracellular amastigotes. At 10 M, these compounds displayed a strong lytic activity. It ranged from 88.4 0.6 to 99.0 1 % for all strains and stages evaluate, with an IC50 /18 h values of 20-84 M and 41-87 M, respectively. The development of intracellular amastigotes was also inhibited by nearly 60% at 25 M. The trypanocidal molecules Y-2 and Y-5 did show different degrees of cytotoxicity depending on the cell line tested, with an IC50 /24 h ranging from 33.2 to 161.2 M. We evaluated the effect of diterpenoids against intracellular T. cruzi forms by immunofluorescent identification of a specific membrane molecular marker (Ssp-4 antigen) of the T. cruzi amastigote forms. The accuracy and reproducibility of the measurements were found to be outstanding when examined by confocal microscopy.

Diterpenoids from Azorella yareta and their trichomonicidal activities

Diterpenoids with trichomonicidal activity were isolated from the aerial parts of Azorella yareta Hauman. One was 13beta-hydroxyazorellane, together with the known constituents mulinolic acid, mulin-11,13-dien-20-oic acid, azorellanol and 13alpha-hydroxyazorellane. Their structures were determined by spectroscopic and chemical methods.

Plants used in Guatemala for the treatment of protozoal infections. I. Screening of activity to bacteria, fungi and American trypanosomes of 13 native plants

Extracts were prepared from 13 native plants used for the treatment of protozoal infections. Activity against bacteria and fungi was demonstrated by dilution procedures; Trypanosoma cruzi was evaluated in vitro against epimastigote and trypomastigotes and in vivo against trypomastigotes. In active extracts, toxicity was evaluated by Artemia salina nauplii, oral acute toxicity (1-5 g/kg) and oral and intraperitoneal subacute toxicity in mice (500 mg/kg). From the plants screened, six showed activity (< or = 2 mg/ml) against bacteria, three against yeasts, five against Microsporum gypseum and five against T. cruzi in vitro and/or in vivo. In vitro and in vivo activity was demonstrated by Neurolaena lobata and Solanum americanum; in vitro or in vivo activity was shown by Acalypha guatemalensis, Petiveria alliacea and Tridax procumbens. Toxicity studies showed that extracts from S. americanum are toxic to A. salina (aqueous, 160 ppm). None showed acute or oral toxicity to mice; S. americanum showed intraperitoneal subacute toxicity.

Plants used in Guatemala for the treatment of protozoal infections: II. Activity of extracts and fractions of five Guatemalan plants against Trypanosoma cruzi

The activities of crude plant extracts of five plants popularly used in Guatemala against bacterial and protozoal infections and some of their fractions have been evaluated against the trypomastigote and epimastigote forms of Trypanosoma cruzi in vitro. The most active fraction of Neurolaena lobata has also been screened in vivo. Main in vitro activities against trypomastigotes have been observed for the hexane and ethanol extracts of N. lobata (Asteraceae). Both extracts were also active against epimastigotes, whereas all other extracts tested had no effect on epimastigotes. For the hexane extracts of Petiveria alliacea (Phytolaccaceae) and Tridax procumbens (Asteraceae) a marked inhibition of trypomastigotes has been found. Also the ethanol extracts of Byrsonima crassifolia (Malpighiaceae) leafs and Gliricidia sepium (Papilionaceae) bark showed some trypanocidal activity. Fraction 2 of the ethanol extract of N. lobata was highly active against T. cruzi as well in vitro as in vivo. The chloroforme fraction of P. alliacea showed a high inhibition of trypomastigotes in vitro. Also three fractions of the active extract of B. crassifolia inhibited T. cruzi trypomastigotes. No fraction of G. sepium bark extract showed a marked trypanocidal activity.

Mutagenicity, insecticidal and trypanocidal activity of some Paraguayan Asteraceae

The insecticidal, moulting inhibition and trypanocidal effects of crude extracts of 7 Paraguayan Asteraceae were evaluated on Triatoma infestans and bloodstream forms of Trypanosoma cruzi, respectively. Both mutagenicity and toxicity were evaluated by sister chromatid exchange (SCE) in human peripheral lymphocyte culture and by the lethality test of Artemia salina. The ethanolic extracts from Chromolaena christieana (stem and bark), Achyrocline satureoides (leaves and flowers) and Mikania cordifolia (root and stem), at a concentration of 250 micrograms/ml, showed the highest percentage of lysis on bloodstream forms of Trypanosoma cruzi. The extracts of Chromolaena christieana and Achyrocline satureoides also presented high mutagenic and toxic capacity when they were evaluated by the SCEs assay and Artemia salina test, respectively. Insecticidal activity was only observed in the hexane extract of flowers of Achyrocline satureoides (45% of mortality), when 0.05 microgram of crude concentration was applied on Triatoma infestans. The ethanolic extracts of stem from Mikania cordifolia and Vernonia brasiliana inhibited the moulting of Triatoma infestans when it was compared with their controls. Since no ethnobotanical information on these plants has been found related to similar use in Paraguay, our findings suggest, for the first time, the potential anti-trypanocidal and moulting inhibition of these Asteraceae.