Insecticidal and genotoxic potential of two semi-synthetic derivatives of dillapiole for the control of Aedes (Stegomyia) aegypti (Diptera: Culicidae)

The effects of two semi-synthetic dillapiole derivatives, ethyl-ether dillapiole and n-butyl ether dillapiole, on eggs and larvae of Aedes aegypti were studied in view of the need for expansion and renovation of strategic action to control this mosquito - the vector of Dengue virus -, which currently shows a high resistance to chemical insecticides. Eggs and third-instar larvae of A. aegypti that had been exposed to different concentrations of these two compounds showed toxicity and susceptibility, with 100% mortality. Classical cytogenetic assays showed genotoxicity caused by the two compounds in A. aegypti from the cumulative effect of nuclear abnormalities, indicating that these derivatives may be potential alternatives to control A. aegypti.

Genetic toxicity of dillapiol and spinosad larvicides in somatic cells of Drosophila melanogaster

BACKGROUND

Higher rates of diseases transmitted from insects to humans led to the increased use of organophosphate insecticides, proven to be harmful to human health and the environment. New, more effective chemical formulations with minimum genetic toxicity effects have become the object of intense research. These formulations include larvicides derived from plant extracts such as dillapiol, a phenylpropanoid extracted from Piper aduncum, and from microorganisms such as spinosad, formed by spinosyns A and D derived from the Saccharopolyspora spinosa fermentation process. This study investigated the genotoxicity of dillapiol and spinosad, characterising and quantifying mutation events and chromosomal and/or mitotic recombination using the somatic mutation and recombination test (SMART) in wings of Drosophila melanogaster.

RESULTS

Standard cross larvae (72 days old) were treated with different dillapiol and spinosad concentrations. Both compounds presented positive genetic toxicity, mainly as mitotic recombination events. Distilled water and doxorubicin were used as negative and positive controls respectively.

CONCLUSION

Spinosad was 14 times more genotoxic than dillapiol, and the effect was found to be purely recombinogenic. However, more studies on the potential risks of insecticides such as spinosad and dillapiol are necessary, based on other experimental models and methodologies, to ensure safe use.

Traditional use of medicinal plants in the boreal forest of Canada: review and perspectives

BACKGROUND

The boreal forest of Canada is home to several hundred thousands Aboriginal people who have been using medicinal plants in traditional health care systems for thousands of years. This knowledge, transmitted by oral tradition from generation to generation, has been eroding in recent decades due to rapid cultural change. Until now, published reviews about traditional uses of medicinal plants in boreal Canada have focused either on particular Aboriginal groups or on restricted regions. Here, we present a review of traditional uses of medicinal plants by the Aboriginal people of the entire Canadian boreal forest in order to provide comprehensive documentation, identify research gaps, and suggest perspectives for future research.

METHODS

A review of the literature published in scientific journals, books, theses and reports.

RESULTS

A total of 546 medicinal plant taxa used by the Aboriginal people of the Canadian boreal forest were reported in the reviewed literature. These plants were used to treat 28 disease and disorder categories, with the highest number of species being used for gastro-intestinal disorders, followed by musculoskeletal disorders. Herbs were the primary source of medicinal plants, followed by shrubs. The medicinal knowledge of Aboriginal peoples of the western Canadian boreal forest has been given considerably less attention by researchers. Canada is lacking comprehensive policy on harvesting, conservation and use of medicinal plants. This could be explained by the illusion of an infinite boreal forest, or by the fact that many boreal medicinal plant species are widely distributed.

CONCLUSION

To our knowledge, this review is the most comprehensive to date to reveal the rich traditional medicinal knowledge of Aboriginal peoples of the Canadian boreal forest. Future ethnobotanical research endeavours should focus on documenting the knowledge held by Aboriginal groups that have so far received less attention, particularly those of the western boreal forest. In addition, several critical issues need to be addressed regarding the legal, ethical and cultural aspects of the conservation of medicinal plant species and the protection of the associated traditional knowledge.

Antibacterial activity of traditional medicinal plants used by Haudenosaunee peoples of New York State

Background

The evolution and spread of antibiotic resistance, as well as the evolution of new strains of disease causing agents, is of great concern to the global health community. Our ability to effectively treat disease is dependent on the development of new pharmaceuticals, and one potential source of novel drugs is traditional medicine. This study explores the antibacterial properties of plants used in Haudenosaunee traditional medicine. We tested the hypothesis that extracts from Haudenosaunee medicinal plants used to treat symptoms often caused by bacterial infection would show antibacterial properties in laboratory assays, and that these extracts would be more effective against moderately virulent bacteria than less virulent bacteria.

Methods

After identification and harvesting, a total of 57 different aqueous extractions were made from 15 plant species. Nine plant species were used in Haudenosaunee medicines and six plant species, of which three are native to the region and three are introduced, were not used in traditional medicine. Antibacterial activity against mostly avirulent (Escherichia coli, Streptococcus lactis) and moderately virulent (Salmonella typhimurium, Staphylococcus aureus) microbes was inferred through replicate disc diffusion assays; and observed and statistically predicted MIC values were determined through replicate serial dilution assays.

Results

Although there was not complete concordance between the traditional use of Haudenosaunee medicinal plants and antibacterial activity, our data support the hypothesis that the selection and use of these plants to treat disease was not random. In particular, four plant species exhibited antimicrobial properties as expected (Achillea millefolium, Ipomoea pandurata, Hieracium pilosella, and Solidago canadensis), with particularly strong effectiveness against S. typhimurium. In addition, extractions from two of the introduced species (Hesperis matronalis and Rosa multiflora) were effective against this pathogen.

Conclusions

Our data suggest that further screening of plants used in traditional Haudenosaunee medicine is warranted, and we put forward several species for further investigation of activity against S. typhimurium (A. millefolium, H. matronalis, I. pandurata, H. pilosella, R. multiflora, S. canadensis).

Antimycobacterial screening of traditional medicinal plants using the microplate resazurin assay

Multidrug-resistant Mycobacterium tuberculosis strains have rapidly become a global health concern. North American First Nations communities have used traditional medicines for generations to treat many pulmonary infections. In this study, we evaluated the antimycobacterial activity of 5 medicinal plants traditionally used as general therapeutics for pulmonary illnesses and specifically as treatments for tuberculosis. Aqueous extracts of Aralia nudicaulis, Symplocarpus foetidus, Heracleum maximum, Juniperus communis, and Acorus calamus were screened for antimycobacterial activity against Bacillus Calmette-Guérin, Mycobacterium avium, and M. tuberculosis H37Ra using the colorimetric microplate resazurin assay. Extracts of Acorus calamus and H. maximum root demonstrated significant antimycobacterial activity comparable to that of the rifampin control (2 microg/mL). Evaluation of the cytotoxicity of these 2 extracts using the MTT assay also showed that the extracts were less toxic to 3 human cell lines than was the DMSO positive control. This study demonstrates that aqueous extracts of the roots of H. maximum and Acorus calamus possess strong in vitro antimycobacterial activity, validates traditional knowledge, and provides potential for the development of urgently needed novel antituberculous therapeutics.

Antifungal activity of medicinal plant extracts; preliminary screening studies

ETHNOPHARMACOLOGICAL RELEVANCE

In the setting of HIV and organ transplantation, opportunistic fungal infections have become a common cause of morbidity and mortality. Thus antifungal therapy is playing a greater role in health care. Traditional plants are a valuable source of novel antifungals.

AIM OF THE STUDY

To assess in vitro antifungal activity of aqueous plant extracts. The minimum inhibitory concentrations were determined for each extract in the setting of human pathogenic fungal isolates.

MATERIALS AND METHODS

Plants were harvested and identification verified. Aqueous extracts were obtained and antifungal susceptibilities determined using serial dilutional extracts with a standardized microdilution broth methodology. Twenty-three fungal isolates were cultured and exposed to the plant extracts. Five known antifungals were used as positive controls. Results were read at 48 and 72 h.

RESULTS

Of the 14 plants analyzed, Fragaria virginiana Duchesne, Epilobium angustifolium L. and Potentilla simplex Michx. demonstrated strong antifungal potential overall. Fragaria virginiana had some degree of activity against all of the fungal pathogens. Alnus viridis DC., Betula alleghaniensis Britt. and Solidago gigantea Ait. also demonstrated a significant degree of activity against many of the yeast isolates.

CONCLUSION

Fragaria virginiana, Epilobium angustifolium and Potentilla simplex demonstrate promising antifungal potential.

Antifungal activity of extracts from medicinal plants used by First Nations Peoples of eastern Canada

From literature describing medicinal usage of plants by First Nations Peoples in eastern Canada, 18 eastern Canadian plants were selected and tested for their antifungal activities. Eight randomly selected tropical plants were also tested for comparative purposes. Four groups of plants were obtained: popular antimicrobial-remedy (n=6), popular non-antimicrobial-remedy (n=6), random temperate (n=6) and random tropical (n=8). Extracts from these plants were tested in disk assays as growth inhibitors of six fungi known to be opportunistic human pathogens (Saccharomyces cerevisiae, Cryptococcus neoformans, Candida albicans, Aspergillus fumigatus, Microsporum gypseum and Trichophyton mentagrophytes). Of the four plant groups tested, extracts from the popular antimicrobial-remedy group were significantly more effective at inhibiting fungal growth based on both overall antifungal activity and number of fungal species inhibited.