Fungicide potential of citronella and tea tree essential oils against tomato cultivation's phytopathogenic fungus Fusarium oxysporum f. sp. lycopersici and analysis of their chemical composition by GC/MS

Tomato is one of the most produced and consumed fruits in the world. However, it is a crop that faces several phytosanitary problems, such as fusarium wilt, caused by Fusarium oxysporum. Thus, this study aimed to evaluate citronella and melaleuca essential oils in vitro potential in the fungus F. oxysporum management. The chemical identification of the components in the essential oils was performed by gas chromatography with flame ionization and mass spectrometer detectors. The IC50 and IC90 were determined by linear regression and the percentage of inhibition of the fungus by analysis of variance. The major compounds in citronella essential oil were citronellal, Geraniol, and citronellol; in melaleuca (tea tree) oil were terpinen-4-ol and α-terpinene. Both oils promoted more significant inhibition at concentrations of 1.5 and 2.5 μL/mL, besides not presenting significant differences with commercial fungicides, confirming the high potential for using this control method in agriculture.

Marine Organisms from the Yucatan Peninsula (Mexico) as a Potential Natural Source of Antibacterial Compounds

A total of 51 sponges (Porifera) and 13 ascidians (Chordata) were collected on the coast of the Yucatan Peninsula (Mexico) and extracted with organic solvents. The resulting extracts were screened for antibacterial activity against four multidrug-resistant (MDR) bacterial pathogens: the Gram-negative Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus. The minimum inhibitory concentrations (MICs) of the organic extracts of each marine organism were determined using a broth microdilution assay. Extracts of eight of the species, in particular the Agelas citrina and Haliclona (Rhizoniera) curacaoensis, displayed activity against some of the pathogens tested. Some of the extracts showed similar MIC values to known antibiotics such as penicillins and aminoglycosides. This study is the first to carry out antimicrobial screening of extracts of marine sponges and ascidians collected from the Yucatan Peninsula. Bioassay-guided fractionation of the active extracts from the sponges Amphimedon compressa and A. citrina displayed, as a preliminary result, that an inseparable mixture of halitoxins and amphitoxins and (-)-agelasine B, respectively, are the major compounds responsible for their corresponding antibacterial activities. This is the first report of the antimicrobial activity of halitoxins and amphitoxins against major multidrug-resistant human pathogens. The promising antibacterial activities detected in this study indicate the coast of Yucatan Peninsula as a potential source of a great variety of marine organisms worthy of further research.

Recent Status and Advancements in the Development of Antifungal Agents: Highlights on Plant and Marine Based Antifungals

The developing resistance in fungi has become a key challenge, which is being faced nowadays with the available antifungal agents in the market. Further search for novel compounds from different sources has been explored to meet this problem. The current review describes and highlights recent advancement in the antifungal drug aspects from plant and marine based sources. The current available antifungal agents act on specific targets on the fungal cell wall, like ergosterol synthesis, chitin biosynthesis, sphingolipid synthesis, glucan synthesis etc. We discuss some of the important anti-fungal agents like azole, polyene and allylamine classes that inhibit the ergosterol biosynthesis. Echinocandins inhibit β-1, 3 glucan synthesis in the fungal cell wall. The antifungals poloxins and nikkomycins inhibit fungal cell wall component chitin. Apart from these classes of drugs, several combinatorial therapies have been carried out to treat diseases due to fungal resistance. Recently, many antifungal agents derived from plant and marine sources showed potent activity. The renewed interest in plant and marine derived compounds for the fungal diseases created a new way to treat these resistant strains which are evident from the numerous literature publications in the recent years. Moreover, the compounds derived from both plant and marine sources showed promising results against fungal diseases. Altogether, this review article discusses the current antifungal agents and highlights the plant and marine based compounds as a potential promising antifungal agents.

Morphological and molecular systematics of the ‘Monanchora arbuscula complex’ (Poecilosclerida : Crambeidae), with the description of five new species and a biogeographic discussion of the genus in the Tropical Western Atlantic

Monanchora Carter, 1883 is a genus of shallow-water marine sponges comprising 16 species distributed worldwide, two of them in the Tropical Western Atlantic (TWA): M. arbuscula (Duchassaing & Michelotti, 1864) and M. brasiliensis Esteves, Lerner, Lôbo-Hajdu & Hajdu, 2012. The former species stands out as one of the most variable demosponges, and is very similar in spicule complement and in secondary metabolite chemistry to the Mediterranean/eastern Atlantic Crambe crambe (Schmidt, 1862), type species of Crambe Vosmaer, 1880. The aim of the present study was to revise the genus Monanchora in the TWA. In addition, we critically analyse the monophyly of Crambe and Monanchora. Maximum Likelihood and Bayesian Inference analyses of 28S and 16S rRNA sequences of the latter genera, and a redescription of the ‘M. arbuscula complex’, revealed three species: M. arbuscula s.s., M. coccinea, sp. nov. and a new species of Acarnidae – Iophon parvachela, sp. nov. Three other new species from the TWA previously assigned to Monanchora were revealed by morphological analyses, and are also described: M. bahamensis, sp. nov., M. megasigmifera, sp. nov. and a new species of Chondropsidae – Batzella catarinensis, sp. nov. A key for species identification is provided. Our results suggest that the Eastern Brazil and Southeastern Brazil Ecoregions may represent centres of diversity for Monanchora in the TWA.