Sustainable natural product-based microstructured systems and biopolymers are strong candidates for use in crop protection. Lignin and gelatin microcapsules loaded with orange essential oil were developed with spray-drying in order to enhance its potential. We evaluated the microparticle controlled release mechanisms, biological effects, structural and thermal properties. A quantitative method using headspace-gas chromatography was developed and evaluated for the controlled release of the essential oils. Controlled release studies showed a linear relationship between the biopolymer and essential oil concentrations when retaining volatile compounds. Thermal analyses demonstrated increases in essential oil stability when microencapsulated, especially for lignin as a biopolymer. These results showed that biopolymer type was the main factor influencing quality analysis parameters. Finally, microcapsules loaded with orange essential oil were applied in a bioassay, and showed gains in toxicity against Spodoptera frugiperda compared to non-encapsulated oil.

Pesticides offer a simple, cost-effective solution to ensure food supplies for a growing world population. However, their environmental performance needs improvement if pesticides are to continue contributing importantly. This study explores the insecticidal potential of a magnesium (II) metal complex containing 1,10-phenanthroline and isovanillic acid (MgPhenIso) against leaf-cutting ant (Atta sexdens rubropilosa) and its symbiotic fungus (Leucoagaricus gongylophorus). The MgPhenIso complex is easy-to-prepare, stable in solid state and in aqueous solution, and resistant to sunlight irradiation. The insecticidal activity of MgPhenIso-containing bait against A. sexdens rubropilosa and L. gongylophorus showed a delayed action mode at 2 mg g-1 (100% kill, 6th day, S50=2b) and suppressed fungus development and growth. These results, together with earlier investigations on MgPhenIso regarding its absence of toxicity to Zebrafish and Wistar male rats, emphasize the potential of this complex as an environmentally friendly insecticide candidate.

Molecular phylogenetic studies separated and united a group of genera that constituted the Spathelia-Ptaeroxylon clade, in which Dictyoloma and Sohnreyia have been included. Our taxonomic interest in the Dictyoloma vandellianum and Sohnreyia excelsa stimulated an investigation of both species searching for limonoids. Leaves from D. vandellianum afforded the new limonoid 1,2-dihydro-1α-hydroxy-8,30-epoxy-cneorin R, and heartwood yielded the new rearranged limonoid dictyolomin. Leaves from S. excelsa afforded the new protolimonoid 3β-angeloyloxy-7α,24,25-trihydroxy-21,23-oxide-14,18-cycloapotirucall-21-methoxycetal and the new cycloheptanyl ring C limonoid with carbonate substituent and named as sohnreyolide. The new limonoids from Sohnreyia and Dictyoloma show similarities with those from Rutaceae and Meliaceae, providing support for moving Spathelia-Ptaeroxylon clade near to these associated large families.

Currently, most food waste is used as animal feed and this process does not take advantage of the available chemical composition. A Brazilian example is the citrus fruit processing wastes (CFPW), which have begun to draw attention due to their biological importance. In order to access the main compounds of this matrix, an efficient and environmentally friendly procedure was tested. From this extract, flavonoids as naringenin, hesperitin, chrysoeriol, sinensetin, 3,5,6,7,3',4'-hexamethoxyflavone, nobiletin, 5-methoxysalvigenin, 3,5,6,7,8,3',4'-heptamethoxyflavone, 3,5,6,7,4'-pentamethoxyflavone and isosakuranetin were identified by high performance liquid chromatography (HPLC-UV), liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-nuclear magnetic resonance (LC-NMR). This study describes the potential use of citrus waste as a source of biologically active compounds. The extraction method proposed for this work was not expensive and the flavonoids were obtained in large amounts, thus, this extraction method is being developed using pilot plant scale-up techniques and will soon be available to the industry at a low cost.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme involved in the Trypanosoma cruzi glycolytic pathway, parasite that causes Chagas' disease. There are only few drugs available to treat this disease, most of which present strong side effects. Natural products constitute a prime source for the discovery of new scaffolds potentially useful for the treatment of several diseases, including Chagas' disease. Bioactivity-guided fractionation of Spiranthera odoratissima extract using T. cruzi GAPDH (TcGAPDH) as a target led to the isolation of the flavonoid tiliroside (kaempferol-3-O-β-D-(6''-trans-p-coumaroyl)-glucopyranoside), identified as an excelent inhibitor of this enzyme and for the first time reported for this plant species. Mechanistic studies of tiliroside showed that it is a reversible non-competitive inhibitor of TcGAPDH. In additon, molecular modeling analysis indicated the binding mode of tiliroside to TcGAPDH. Therefore, the identification of tiliroside as TcGPADH inhibitor in a complex matrix such as the plant crude extract and the discovery of a new binding site may contribute to the opening of new paths in the search for natural product inhibitors of this enzyme.

Microcapsules of sugarcane bagasse lignin loaded with organic extracts of neem (Azadirachta indica) were prepared and evaluated as potential bioinsecticides. Lignins were extracted and modified by oxidation and acetylation reactions providing different biopolymers. Afterwards, they were characterized through several analytical techniques. The formulations were initially prepared as colloidal suspension of lignin nanoparticles, which were then spray-dried. The products were submitted to quality control protocols using high performance liquid chromatography (HPLC), thermal and photochemical degradation studies, followed by biological assays against Spodoptera frugiperda and Diatraea saccharalis. The formulations showed increases in both thermal and photo stability of approximately 40% compared with control samples. All the formulated microparticles were efficient against the insects evaluated and required a shorter time to achieve 100% mortality than the controls. The use of sugarcane bagasse lignins to prepare microparticles improved the resistance of neem extracts against abiotic factors, retaining the biological activity of this biopesticide.

A methanol-soluble fraction of the dichloromethane extract from the culture broth of A. alternata AT4303 strain afforded the following five known mycotoxins: alternariol, alternariol monomethyl ether, altenusin, altenuene and altertoxin I. A hexane-soluble fraction of the dichloromethane extract yielded the steroids ergosterol and ergosterol peroxide, and alternariol monomethyl ether. The concentrated ethyl acetate extract afforded the nucleoside uridine, uracil and inosine. The micro-extracts obtained from this strain in solid media were analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), and the following five known toxins were identified: ACTG-C, D, E and F and AK-toxin II. The major toxins produced by the tangerine pathotype ACT-toxins appear to be absent in strain AT4303. However, the low concentration of ACT-toxins appears to be responsible for their lack of detection in this study. Some compounds isolated from citrus plants were tested for in vitro activity against this strain. The results indicated that 17.3 µM apigenin-7-O-rutinoside inhibited by 80% conidial germination and appressorium development.