J. Guillermo Avila

Antifungal and Antibacterial Activities of Araucaria araucana (Mol.) K. Koch Heartwood Lignans

Abstract Five lignans (secoisolariciresinol, pinoresinol, eudesmin, lariciresinol, and lariciresinol-4- methyl ether) were isolated from an MeOH extract from Araucaria araucana (Mol.) K. Koch wood for the first time in this species and their structures determined with spectroscopic methods. The antimicrobial activities of these compounds were determined for the bacteria Citrobacter sp., Bacillus subtilis, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, and Pseudomonas aeruginosa, and for the white rooting and staining fungi Mucor miehei, Paecilomyces variotii, Ceratocystis pilifera, Trametes versicolor, and Penicillium notatum, and in addition, the MeOH extract was evaluated against Aspergillus niger, Candida albicans, Fusarium moniliforme, F. sporotrichum and Trichophyton mentagrophytes. The most sensitive bacteria against pinoresinol were the Gram-positive. However, secoisolariciresinol exhibited a significant antifungal activity on fungi of white rooting and wood staining and this compound completely inhibited the mycelial growth of T. versicolor and C. pilifera at 300 and 400 μg per disc, respectively, whereas pinoresinol showed a moderate inhibitory activity. On the other hand, the MeOH extract had the highest activity against rooting and staining and pathogenic fungi as well as T. versicolor, Fusarium spp. and Trichophyton mentagrophytes, inhibiting completely the growth at 400 μg per disc

Chapter 1 Natural compounds as antioxidant and molting inhibitors can play a role as a model for search of new botanical pesticides

Publisher Summary There is a widespread effort to find new pesticides, and it is currently focused on natural compounds, such as flavonoids, coumarins, terpenoids, and phenolics from diverse botanical families from arid and semi-arid lands of Mexico and Americas. Additional experimental work has been carried out with natural products that are potential models for defensive substances against insect and fungal predators and as enzyme inhibitors, such as tyrosinase or acetylcholinesterase (AChE). The increasing interest in the possible application of secondary metabolites for pest management has directed the investigation toward the search for new sources of biologically active natural products with new mode, sites, and mechanisms of action. These characteristics may enhance their value as commercial pesticides. This chapter presents a review of extracts and bioactive compounds isolated by one study group from selected endemic botanical species and their antioxidant and biological activities. The chapter describes antifeedant activities shown by assayed compounds—that is, insecticidal or insect growth regulatory (IGR) activities and their activities on some enzymes.

Plant growth inhibitory activities by secondary metabolites isolated from Latin American flora

This chapter studies phytochemicals that are biodirected, to find botanical-origin biopesticides targeted against weeds. It describes the identification of some monoterpenes, diterpenes, sesquiterpene lactones, limonoids, triterpenes, coumarins, and flavonoids, including their chemical derivatives from plants belonging to the families Asteraceae, Celastraceae, Gomortegaceae, Lauraceae, Meliaceae, Monimiaceae, Poaceae, and Winteraceae. The findings show that some natural compounds or their derivatives possess plant growth regulatory (PGR) or herbicidal activities. Compounds with acetylated and α-β-unsaturated carbonyl derivatives showed mainly PGR activity. It seems that an α-methylene-γ-lactone and a group α,β-unsaturated carbonyl are important for structural activity requirements. Allelopathic activities were assayed with Triticum aestivum, T. vulgare, Trifolium pratense, T. alexandrinum, T. angustifolium, Lolium multiflorum, Lactuca sativa, Physalis ixocarpa, and Raphanus sativus as weed seeds models. All of them are weedy pests in wheat, oat, potatoes, corn, bean, and other important crops of Latin America. Very little is known about the inhibitory activity of these natural compounds and their derivatives. Natural compounds that we have isolated represent a valuable resource for the study toward noxious weedy species of the allelopathic activities of these plants and their control. Progress in biochemical and allelopathic characterization of this pathway is outlined.

Antifungal and Antibacterial Activities of Endemic Pittocaulon. spp. from Mexico

Abstract Extracts from Pittocaulon. spp. (Asteraceae) have been used in folk medicine to treat many ailments, particularly as anti-inflammatory and antimicrobial. Neither the bioactive components responsible nor the mechanisms involved have been evaluated. Here we report the antibacterial activities of their methanol and CH2Cl2 extracts and the effects on some fungal strains treated with CH2Cl2 extracts from root, stems, and flowers of P. praecox. (Cav.) H. Rob. & Brett., P. hintonii. H. Rob. & Brett., P. filare. (McVaugh) H. Rob. & Brett, P. velatum. (Greenm) H. Rob. & Brett., and P. bombycophole. (Bullock) H. Rob. & Brett. Thirteen extracts were obtained with MeOH and CH2Cl2 solvents from aerial parts and roots of five Pittocaulon. spp. for the first time in this species, and their antimicrobial activities were determined. The antimicrobial activities of these extracts were evaluated against the bacteria Staphylococcus aureus., Staphylococcus epidermidis., Bacillus subtilis., and Vibrio cholerae. (one El Tor strain, and a clinic case CDC-V12). Additionally, the CH2Cl2 extract was evaluated against Aspergillus niger., Fusarium moniliforme., Fusarium sporotrichum., Rizoctonia solanii., and Trichophyton mentagrophytes.. The most sensitive bacteria against these extracts were B. subtilis., S. epidermidis., and V. cholerae., a key bacterium in contaminated water. However, CH2Cl2 extracts from P. praecox., P. bombycophole., and P. hintonii. exhibited a significant antifungal activity against the fungal strains F. sporotrichum., R. solanii., and T. mentagrophytes.: at 1000 μg per disk, these extracts completely inhibited the mycelial growth of these fungi.