Um estudo da folha de Morinda citrifolia L. (Noni) : da anatomia às atividades biológicas

Abstract

leaves, permanent and elliptical. The species is native of the Southeast Asia and has been adapted very well to the Brazilian climate. Approximately 160 compounds have been identified in various parts of the noni, and most of them belong to the group of phenolic compounds, organic acids and alkaloids. For this reason, the plant produces a wide range of biological activity and nutritional value, offering health benefits, with antioxidant, anti-inflammatory, analgesic, immunomodulatory, antibacterial, antitumor activities, among others. Still, studies with this plant are very recent, with a few reports of its leaf. OBJECTIVE: perform an anatomical and chemical characterization of noni leaves, in addition to evaluating the effectiveness of the leaf extract for treating depression, anxiety, compulsion and memory, and toxicity in Swiss mices. MATERIALS AND METHODS: Adult leaves of 30 individuals were collected in the city of Sinop-MT. For anatomical study, there was cross-sections and paradermal of the leaf blade, then stained with Safranin and analyzed in light microscope. Histochemical tests were carried out with specific reagents to verify the substances. The hidroalcoholic extract was obtained by maceration and realized his phytochemical screening. For acute and subchronic toxicological tests, Hippocratic tests were avaliated of ALT and AST assessment in Swiss mice, after treatment with extract. For evaluate antidepressant activity, anxiolytic, an anticompulsive and memory, behavioral tests were performed with Swiss mice. After administration of the extract, the animals were subjected to the test spontaneous locomotor activity, elevated plus maze, forced swimming, inhibitory avoidance of the "step down" and testing to hide balls. Data were analyzed by Kruskal-Wallis followed by Dunn's post-hoc test for inhibitory avoidance of the "step-down" and analysis of variance (ANOVA) followed by post hoc Student-Newman-Keuls test for other behavioral and toxicological. RESULTS AND DISCUSSION: The leaf is hipostomatic with paracytic stomata; uniseriate epidermis on both sides, with dense cuticle on the adaxial surface and glandular trichomes with uniseriate about six cells. Mesophyll presents dorsiventral and calcium oxalate crystals in the form of raphides and Druze. In the region of the midrib, it is observed collenchyma and fundamental parenchyma on both sides and collateral vascular bundle. As the mesophyll as the region of the vascular bundle presents secretory cells. The histochemical tests and phytochemical screening showed the presence of phenolic compounds, lignin, alkaloids, saponins and cardioactive glycosides. Toxicological tests showed abnormal values of serum ALT and AST. Behavioral tests showed statistically significant values for forced swimming test, inhibitory avoidance of the "step-down" test and to hide balls. CONCLUSION: The anatomical study has structural features that contribute to the identification of the medicinal plant. The histochemical tests and phytochemical screening made it possible to confirm the presence of secondary compounds in the noni leaf. Studies have shown possible hepatotoxicity and possibility antidepressant activity, anticompulsive and stimulating the memory from the noni extract.