Immunotoxicological Evaluation of Schinus molle L. (Anacardiaceae) Essential Oil in Lymphocytes and Macrophages

Abstract

Schinus molle L. is used to treat various diseases; however, the literature lacks information regarding its possible immunotoxic effects. The aim of the study was to investigate the immunotoxic effects of essential oil from leaves of Schinus molle L. in cultures of human lymphocytes and macrophages. The cultures were treated with essential oil (EO) of Schinus molle L. and subsequently subjected to genotoxic analysis (comet assay), mutagenic analysis (micronucleus frequency and chromosomal aberration), and cytotoxic (cell viability) and functional parameters (interleukins secretions). Our analyses have determined that the essential oil from leaves of Schinus molle L. presents several compounds with α-pinene being the major compound; in addition, the compound verbenene was firstly identified; genotoxic effects were detected only in macrophages and only at the two highest concentrations tested. An important finding is that Schinus molle L. oil causes an activation of the immune system. This action has its mechanism centered by the cascade nitric oxide-interleukin-10-tumor necrosis factor alpha.

Figure 1

Assessment of cell proliferation for determining the LD₅₀ of the essential oil of Schinus molle L. culture of (a) human lymphocytes and (b) human macrophages by linear regression. Data expressed as mean ± standard deviation and it was performed at each test triplicate. In each graph the different letters represent a statistically significant difference at p <0.05.

Figure 2

Evaluation of cell viability in cultures of lymphocytes and human macrophages exposed to different concentrations of the essential oil of Schinus molle L. Data expressed as mean ± standard deviation and it was performed at each test triplicate (n=3). In each graph the different letters represent a statistically significant difference at p <0.05.

Figure 3

Genotoxic effects of S. molle L. essential oil. In (a) the results of the micronuclei (expressed as nuclear division index), in (b) the numerical chromosomal instability, and in (c) the index of DNA damage. Data expressed as mean ± standard deviation and it was performed at each test triplicate (n=3). In each graph the different letters represent a statistically significant difference at p <0.05.

Figure 4

Functional evaluation of the immune system cells. In (a) we have the results of interleukin-6 secretion, in (b) the secretion of interleukin-10, in (c) the production of tumor necrosis factor alpha, and in (d) the production of nitric oxide (NO). Data expressed as mean ± standard deviation and it was performed at each test triplicate (n=3). In each graph the different letters represent a statistically significant difference at p <0.05.