Óleos essenciais de Cinnamodendron dinisii Schwacke e Siparuna guianensis Aublet: composição química, caracterização das estruturas secretoras e avaliação do potencial biológico

Abstract

The aims of this study were to determine the chemical composition of essential oils of Cinnamodendron dinisii Schwacke (pimenteira) and Siparuna guianensis Aublet (negramina), their antioxidant, antibacterial, antifungal, trypanocidal, cytotoxic and hemolytic activity and to evaluate their capacity to cause damage in human lymphocyte DNA, besides characterizing their secretory structures. The obtaining of the essential oils was conducted by the hydrodistillation technique using a modified Clevenger apparatus, and the identification and quantification of constituents, by GC/MS and GC-FID analyses. The antioxidant activity was evaluated using the β-carotene/linoleic acid system and the DPPH radical sequestering method. The evaluation of the antibacterial activity was conducted through the agar well diffusion technique, and the antifungal activity, by the disk diffusion technique. The trypanocidal activity was evaluated on Trypanosoma cruzi epimastigote forms and the cytotoxic on Vero cells; both were determined by the MTT method. The hemolytic activity was evaluated by spectrophotometric measurements of the hemoglobin (Hb) released of from the erythrocytes. The damage caused in lymphocyte cell DNA was appraised by the comet assay and the characterization of the secretory structures was made by SEM and through histochemical tests with the Nadi reagents, Sudan III and ferric chloride. The yields of the essential oils were 2.03% and 0.31% and the moisture contents were 60.67% and 64.67% for the fresh leaves of C. dinisii and S. guianensis, respectively. In the chromatographic analyses, the majority constituents found in the essential oil of C. dinisii were the α-pinene (35.41%) β-pinene (17.81%), sabinene (12.01%) and the bicyclogermacrene (7.59%). In the essential oil of S. guianensis, were identified as majority constituents the β-myrcene (13.14%), germacrene D (8.68%) and the bicyclogermacrene (16.71%). The antioxidant activity by the β-carotene/linoleic acid test was low and was not evidenced by the DPPH test, for both appraised oils. The trypanocidal activity obtained was IC50 = 282.93 µg mL-1 for C. dinisii oil and 124.00 µg mL-1 for S. guianensis, values considered high. The two essential oils presented little inhibitory effect on bacteria, presenting high MIC values and satisfactory inhibitory effect on the fungi appraised, with low MIC values. The cytotoxic activity for Vero cells found was high (CC50 =35.72 µg mL-1 for C. dinisii oil and 38.01 µg mL-1, for S. guianensis). The essential oils under study presented a elevated hemolytic effect in all of the hematocrit concentrations (Ht) appraised. Through the comet assay, it was observed that the oils caused significant damage to lymphocyte DNA, and the essential oil of C. dinisii caused the higher damage. The characterization of the secretory structures of the essential oils revealed the presence of internal secretion cells (secretor cavities) in both appraised species.