Extrato de folhas de caju (Anacardium Occidentale l.) e de cajuí (Anacardium Microcarpum d.): prospecção fitoquímica, atividade antioxidante, antimicrobiana e anti-inflamatória, in vitro e in vivo

Abstract

Mankind has always sought in plants alternative treatments to pathologies, and the knowledge and use of them, for many traditional communities, may be the only therapeutic option. Medicinal plants have been used for therapeutic purposes, in some cases without so much as the knowledge of their active ingredients and toxicity. On the other hand, there are several known actions performed by plant derivatives, being some: antiviral, antispasmodic, analgesic, antimicrobial, healing, expectorant, relaxing, antiseptic, respiratory, larvicidal, vermifuge and anti-inflammatory action. The increase of multiresistant bacteria stimulates interest in the search for new therapeutic alternatives with antimicrobial power. This has caused an emergence of research in the area, especially from plant resources. The Anacardium occidentale L (cashew) plant with a succulent pseudofruit, is characteristic of the tropical region of Brazil, and has pharmacological activities proven by the anti-inflammatory, astringent and antitumoral effects. Anacardium microcarpum (cajuí), present in the Cerrado region of the Amazon and in the Northeast, Center-West and Southeast regions of Brazil, presents a small pseudofruit and in its secondary metabolism produces phenolics, compounds with anti-inflammatory, antioxidant and antimicrobial activities. The aims of this study were to evaluate the antimicrobial activity of leaf extracts of Anacardium occidentale (cashew) and Anacardium microcarpum (cajuí) against multiresistant bacteria, and its antioxidant actions in vitro and in IL-10 knockout mice. The results were divided into three articles, which are composed of a review of the antimicrobial and antioxidant actions of pequi (Caryocar brasiliense), cashew (Anacardium occidentale) and cajuí (Anacardium microcarpum) and two original articles, one with antioxidant and antimicrobial in vitro and another with in vivo oxidative stress assays. Article 1. Antioxidant and antimicrobial activities of crude extracts and fractions of cashew (Anacardium occidentale L.), cajuí (Anacardium microcarpum) and pequi (Caryocar brasiliense C). A systematic review. A systematic review of the works that presented results of tests with extracts of the parts of the vegetal species mentioned above was elaborated. The databases Pubmed / Medline, Virtual Health Library (Lilacs and Scielo) and Science Direct were analyzed. Of a total of 425 articles, 32 were included, being 19 studies with Anacardium occidentale, 3 with Anacardium microcarpum and 10 with Caryocar brasiliense. The most used in vitro antioxidant capacity evaluation technique was DPPH and the most used microbiological capacity evaluation technique was the minimum inhibitory concentration and disk diffusion. Many articles were not found due to the limitations of the database search. Most of the tests described demonstrated potentially positive results to the antioxidant and antimicrobial actions when using the species studied. The results provide important data and perspectives for the use of natural products that can contribute to the treatment of various diseases, especially non-communicable diseases (NCD). Article 2. Phytochemical characterization, antimicrobial and antioxidant activities of Anacardium occidentale L and Anacardium microcarpum leaves, in vitro. Ethanolic extracts of A. occidentale L and A. microcarpum were prepared from crunched dry leaves for use in the trials. The DPPH and ABTS methodologies were used to evaluate the antioxidant power in vitro. Thin-layer chromatography was the technique of choice for phytochemical prospecting and HPLC (high performance liquid chromatography) to verify the presence of anacardic acids. The phenolics and total flavonoids of the extracts were quantified by spectrophotometry and linear regression. For the microbiological tests, the minimum inhibitory concentration in 96 microplates from hospital originated multiresistant strains was used. The ethanolic extracts of Anacardium occidentale and Anacardium microcarpum showed capture of similar DPPH and ABTS radicals and 2.34 and 1.64 mg GAE (galic acid equivalents) of total phenolics and total flavonoid values of 0.34 and 0, 29 mg RE (routine equivalents), respectively. The phytochemical prospection showed the presence of flavonoids, tannins, saponins, essential oils and triterpenes. The presence of the secondary flavonoid metabolites and tannins may favor the digestion of nutrients, the organic functioning of the body, activate the antioxidant capacity and modify the synthesis of eicosanoids, with anti-inflammatory response. A. microcarpum was the extract with the lowest minimum inhibitory concentration, with a value of 0.78 mg / mL in S. aureus strains. The ethanolic extracts of the leaves presented microbicidal and antioxidant capacity in vitro, which leads us to believe that they are potential products for the elaboration of a phytotherapeutic medicine. However, more studies are fundamental to uncover the gaps still existing in the knowledge about these plants. Article 3. Antioxidant activity of Anacardium occidentale D. and Anacardium microcarpum L. leaves in interleukin-10 knockout mice. For the tests, interleukin-10 knockout mice were used, divided into six groups (control, with injury and treated): control; paracetamol; paracetamol + Anacardium occidentale; paracetamol + Anacardium microcarpum; Anacardium occidentale and Anacardium microcarpum. Retroorbital blood was collected for leukocyte count and serum was separated for analysis of the biochemical profile of alanine aminotransferase (ALT), aspartate transferase (AST), gamma glutamyl transferase (GGT), alkaline phosphatase (FA), total cholesterol and triglycerides. Liver maceration was used for the analysis of oxidative stress from the malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione and carbonylated protein assays. The histopathological analysis of the liver was performed, observing the changes in the tissue in each group, analyzing the presence or absence of changes in the cytoplasm and nucleus; steatosis; inflammatory infiltrate and cholestasis. Oxidative stress in liver maceration showed better results in mice treated with Anacardium microcarpum in most of the enzymes. The result of the carbonylated protein with a value of 33.17 nmol / mg of the paracetamol group and 13.03 nmol/mg was also highlighted. The mice treated with the two extracts, without paracetamol injury and treated with A. microcarpum after injury, presented significant results for SOD and CAT, demonstrating efficiency in the elimination of reactive oxygen species. In the histopathological analysis of the liver, the mice treated with the two extracts presented reduction in the inflammatory infiltrate and cholestasis, demonstrating a decrease in the inflammatory process after the injury by paracetamol. The results confirm the hypothesis of antioxidant activity of the leaves of Anacardium occidentale and Anacardium microcarpum, which suggests, from more detailed studies, the use of leaves to develop a phytotherapeutic agent.