A comparative study of the chemical composition of essential oils of two very similar species of the Verbenaceae family (Lantana camara and L. radula) revealed that the main components of essential oil of L. camara were germacrene-D (19.8%) and E-caryophyllene (19.7%), while those of L. radula were E-caryophyllene (25.3%), phytol (29.2%) and E-nerolidol (19.0%). We have hypothesized that the observed differences could contribute to the differentiated reaction of the two species of Lantana to the attack of the phytopathogenic fungi Corynespora cassiicola. An experiment, involving C. cassiicola cultivation in culture media containing volatile oils of the two species demonstrated that the oils of L. radula were more fungistatic than the oils of L. camara, in accordance with the in vivo observations. It is likely that E-nerolidol and phytol, only found in the oil of L. radula, play a significant role in the effects of L. radula on C. cassiicola.

Alternariol and monomethylalternariol are natural phytotoxins produced by some fungal strains, such as Nimbya and Alternaria. These substances confer virulence to phytopathogens, yet no information is available concerning their mode of action. Here we show that in the micromolar range alternariol 9-methyl ether is able to inhibit the electron transport chain (IC50 = 29.1 ± 6.5 μM) in isolated spinach chloroplasts. Since its effectiveness is limited by poor solubility in water, several alternariol analogues were synthesized using different aromatic aldehydes. The synthesized 6H-benzo[c]cromen-6-ones, 5H-chromene[4,3-b]pyridin-5-one, and 5H-chromene[4,3-c]pyridin-5-one also showed inhibitory properties, and three 6H-benzo[c]cromen-6-ones were more effective (IC50 = 12.8-22.8 μM) than the lead compound. Their addition to the culture medium of a cyanobacterial model strain was found to inhibit algal growth, with a relative effectiveness that was consistent with their activity in vitro. In contrast, the growth of a nonphotosynthetic plant cell culture was poorly affected. These compounds may represent a novel lead for the development of new active principles targeting photosynthesis.

Here we report the tail-to-tail dimerization of tetra-IJcarboxymethoxy)calixij4]arene in both solution and solid state phases using ESI-orbitrap UHRMS, 1 H-NMR and single-crystal X-ray diffraction techniques. Three sodium ions are encapsulated into the dimeric structure which is also stabilized by hydrogen bonds between carboxyl moieties undergoing partial deprotonation.

Infections caused by dermatophytes, mainly Trichophyton rubrum,are often vulnerable to relapses upon cessation of antifungal therapy, reinforcing the need of new antifungals. Aldimines have potential biological activities, but there are few reports on their antifungal profile. The aim of this study was to evaluate the antifungal activity of 2-(benzylideneamino)phenol (3A3) and 4-(benzylideneamino)phenol (3A4) against dermatophytes. We determined the minimum inhibitory concentration, minimum fungicidal concentration, time-kill curves and fractional inhibitory concentration of the combination of 3A3, 3A4 and itraconazole against a set of isolates of T. rubrum and T. interdigitale. 3A3 was tested in a murine model of dermatophytoses caused by T. rubrum, and the effect on phagocytosis was assessed. The MIC values ranged from 8 to 32 μg/mL for 3A3 and from 64 to 256 μg/mL for 3A4. The interaction between 3A3 and 3A4 with itraconazole proved to be synergistic and indifferent, respectively. 3A3 was as efficient as itraconazole in reducing the fungal burden on the skin of mice, being this effect associated with the influx of neutrophil and macrophage. Also, 3A3 was able to increase the internalization of conidia by macrophages. Altogether, our data encourage future clinical studies with 3A3 to treat dermatophytoses.

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