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The antifungal activity of polygodial, a secondary metabolite extracted from Canelo, on mycelial growth of different Botrytis cinerea isolates has been evaluated. The results show that polygodial affects growth of normal and resistant isolates of B. cinerea with EC50 values ranging between 117 and 175 ppm. In addition, polygodial markedly decreases the germination of B. cinerea, i.e., after six hours of incubation the percentage of germination decreases from 92% (control) to 25% and 5% in the presence of 20 ppm and 80 ppm of polygodial, respectively. Morphological studies indicate that conidia treated with polygodial are smaller, with irregular membrane border, and a lot of cell debris, as compared to conidia in the control. The existence of polygodial-induced membrane damage was confirmed by SYTOX® Green uptake assay. Gene expression studies confirm that the effect of polygodial on B. cinerea is mainly attributed to inhibition of germination and appears at early stages of B. cinerea development. On the other hand, drimenol, a drimane with chemical structure quite similar to polygodial, inhibits the mycelial growth efficiently. Thus, both compounds inhibit mycelial growth by different mechanisms. The different antifungal activities of these compounds are discussed in terms of the electronic density on the double bond.

Plant cell culture is a source of plant material from which bioactive metabolites can be extracted. In this work, the in vitro propagation of Leptocarpha rivularis, an endemic Chilean shrub with anticancer activity, is described. Different media were tested and optimized for the introduction, propagation, and rooting steps of the micropropagation process. At the end of this process, 83% of plants were successfully acclimatized under greenhouse conditions. Callus induction from the internodal stem segment was performed using various combinations of phytohormones. Green-colored, friable, and non-organogenic callus was generated with a callus induction index higher than 90%. The chemical composition of extracts and callus, obtained from clonal plants, was assessed and the results indicate that the phytochemical profiles of extracts from micropropagated plants are like those found for plants collected from natural habitats, leptocarpine (LTC) being the major component. However, no LTC was detected in callus extract. HeLa and CoN cells, treated with LTC or extract of micropropagated plants, exhibit important diminution on cell viability and a drastic decrease in gene expression of IL-6 and mmp2, genes associated with carcinogenic activity. These effects are more important in cancer cells than in normal cells. Thus, micropropagated L. rivularis could be developed as a potential source of efficient antiproliferative agents.

Herein, we have displayed an easy way to produce monodisperse spinel nanoparticles (NPs) and the antifungal activity of CoFe2O4, Co0.5Zn0.5Fe2O4 and ZnFe2O4 nanostructures. Firstly, the structural, morphological and magnetic properties of each NP were investigated through x-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometer (VSM). The XRD data showed diffraction peaks related to the crystalline spinel phase. The TEM micrographs displayed monodisperse NPs with spherical morphology. The average sizes of CoFe2O4, Co0.5Zn0.5Fe2O4 and ZnFe2O4 NPs were 6.87 ± 0.05 nm, 5.18 ± 0.01 nm and 11.52 ± 0.09 nm, respectively. The VSM data indicated that the nanostructures are superparamagnetic at room temperature. Afterward, the antifungal properties of the Co/Zn-based ferrite NPs against Botrytis cinerea were tested. So, the inhibition of mycelial growth by different concentrations (45 – 360 ppm) of NPs was measured. The most effective nanostructure was CoFe2O4, with an EC50 value of 265 ppm. Further, to elucidate how the NPs are affecting B. cinerea, reactive oxygen species (ROS) production was measured. The results indicated that the CoFe2O4 monodisperse NPs could induce a burst of ROS in B. cinerea, promoting cellular damage.

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