Research has shown that chitosan induces plant stress tolerance and protection, but few studies have explored chemical modifications of chitosan and their effects on plants under water stress. Chitosan and its derivatives were applied (isolated or in mixture) to maize hybrids sensitive to water deficit under greenhouse conditions through foliar spraying at the pre-flowering stage. After the application, water deficit was induced for 15 days. Analyses of leaves and biochemical gas exchange in the ear leaf were performed on the first and fifteenth days of the stress period. Production attributes were also analysed at the end of the experiment. In general, the application of the two chitosan derivatives or their mixture potentiated the activities of the antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and guaiacol peroxidase at the beginning of the stress period, in addition to reducing lipid peroxidation (malonaldehyde content) and increasing gas exchange and proline contents at the end of the stress period. The derivatives also increased the content of phenolic compounds and the activity of enzymes involved in their production (phenylalanine ammonia lyase and tyrosine ammonia lyase). Dehydroascorbate reductase and compounds such as total soluble sugars, total amino acids, starch, grain yield and harvest index increased for both the derivatives and chitosan. However, the mixture of derivatives was the treatment that led to the higher increase in grain yield and harvest index compared to the other treatments. The application of semisynthetic molecules derived from chitosan yielded greater leaf gas exchange and a higher incidence of the biochemical conditions that relieve plant stress.

Garcinia brasiliensis, popularly known as Bacupari, is native to the Amazon and commonly used in folk medicine Fukugetin,

The present study describes for the first time the antigenotoxic and antioxidant properties of Stryphnodendron adstringens (Mart.) Coville, Fabaceae ("barbatimão") leaves. The aqueous (AEB), water fraction (WFB) and ethanolic (EEB) extracts of leaves were obtained and they presented high content of phenolic compounds, flavonoids and proanthocyanidins. WFB and EEB inhibited the genotoxicity induced by cyclophosphamide. WFB inhibited the DNA lesion formation and both WFB and EEB decreased significantly (p<0.05) micronucleus formation. All extracts also showed high DPPH radical scavenging activity and reducing power. In conclusion all extracts presented antioxidant activity and WFB and EEB protected cells from genotoxicity induced by cyclophosphamide in rat bone marrow cells. Thus, our results support the beneficial effects of the barbatimão extracts as an anticarcinogenic agent.

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The aim of this work was to evaluate the effect of Salicylic acid, 2,4-D and 2-iP on the production of total phenolic and flavonoids as well in the levels of fukugetin and 7-epiclusianone in callus of Garcinia brasiliensis zygotic embryos. For this, Bacupari callus HIGHLIGHTS • Bacupari callus presents significative levels os phenolics and flavonoids.• Specifically, it was idenficated fukugetin e 7-epiclusianone • Growth regulators and salicylic acid affected the occurrence these substances. Teixeira, M.G.; et al.