Caracterização físico-química e avaliação dos efeitos antibacteriano, antioxidantes e citotóxicos do exsudato de Anacardium occidentale L. (goma do cajueiro): um possível tratamento para mucosite oral

Abstract

Oral mucositis (OM) is an important acute adverse effect in the oral cavity in patients undergoing chemotherapy and/or radiotherapy. The lesions can lead to a considerable decrease in quality of life, causing difficulty in eating, pain or burning when swallowing and can represent a gateway for opportunistic infections. The scientific literature describes some palliative treatments for oral mucositis, however they do not bring great benefits for the prevention and/or treatment of the disease. Medicinal plants have strongly contributed to the development of new therapeutic strategies through their secondary metabolites, among them is Anacardium occidentale L., which has already shown that the bark, leaves and bark oil are used in medicinal preparations such as anti -inflammatory, and the gum has recently been used in both the pharmaceutical and food industries and has many pharmacological properties already described, such as healing, antibacterial, antifungal, gastroprotective, antidiarrheal and antitumor activity. To characterize and investigate the antibacterial, antioxidant and cytotoxic activities of Anacardium occidentale L. (cashew tree gum) exudate as na alternative possible for oral mucositis. The physical-chemical characterization was carried out regarding color, odor, solid appearance, pH and viscosity. The total, reducing and non-reducing sugars present in cashew tree gum were also analyzed. Antibacterial screening was carried out on Gram-positive and Gram-negative strains of clinical importance and collection, determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (CBM) against the selected strains. The combined use of cashew tree gum with synthetic antibacterials was evaluated using the infusion disc method. Subsequently, the activity of the gum on the formation and pre-formation of biofilms was evaluated. The oxidant and antioxidant activity on human hemoglobin was determined. Human blood samples of types A, B and O were subjected to cytotoxicity assessment at extract concentrations of 125μg/mL to 1000μg/mL against hemolytic and anti-hemolytic activity assays. Cashew tree gum presented an MIC and MBC of 1000µg/mL for Streptococcus mutans from the ATCC25175 collection and Pseudomonas aeruginosa from the ATCC9027 collection, with a bactericidal nature. It was possible to identify a synergistic effect when associated with azithromycin against the Pseudomonas aeruginosa strain and an indifferent effect against Streptococcus mutans. In relation to the biofilm, the cashew tree gum reduced the formation, but was not able to destroy the pre-formed biofilm. No oxidizing activity of the cashew tree gum was observed, but with regard to its antioxidant activity, it was found that the gum was able to reduce the effect of the oxidizing agent phenylhydrazine by 59.7%. In terms of hemolytic activity, at the concentrations tested, it presented low activity on human erythrocytes of the ABO system, and presented anti-hemolytic activity, reducing the degree of hemolysis caused by the hypotonic solution in type A blood by 42.78%, 62% in type B blood. and 49.96% in blood O. The data found demonstrate that cashew tree gum is a candidate for possible therapeutic applications against oral mucositis and its toxicity profile indicates feasibility for future studies.