Cytotoxicity of Cymbopogon citratus (DC) Stapf fractions, essential oil, citral, and geraniol in human leukocytes and erythrocytes.

ETHNOPHARMACOLOGY RELEVANCE: Our recently published paper demonstrated that ethyl acetate fractions obtained from Cymbopogon citratus (DC.) Stapf (C. citratus) leaves, which are consumed as infusion in folk medicine due to their therapeutic properties, are rich in polyphenols and exhibit promising antioxidant activity by acting through different mechanisms in vitro. However, studies regarding the toxicity of these fractions are necessary to investigate their safe use in future biomedical applications. AIM OF THE STUDY: This study aimed to investigate the toxicity of ethyl acetate (obtained in acidic and basic conditions and after the essential oil removal from the leaves) and chloroform fractions, essential oil, and its pure constituents, citral and geraniol. MATERIALS AND METHODS: The toxicity of C. citratus samples was evaluated by using Artemia salina (A. salina) and human blood cells (leukocytes and erythrocytes). RESULTS: The A. salina lethality assay demonstrated that C. citratus fractions were moderately toxic with LC50 values ranging from 146.12 to 433.15 µg mL-1, whereas the essential oil and isolated compounds were highly toxic with LC50 lower than 100 µg mL-1. Leukocyte viability decreased after incubation in the presence of the fractions obtained after the essential oil removal from the plant leaves, as well as in the presence of essential oil, citral and geraniol. The same samples increased the osmotic fragility of erythrocytes, and field emission gun scanning electron microscopy (FESEM) analysis revealed significant changes in cell morphology. Interestingly, our results suggest that the previous removal of essential oil from plant leaves facilitated the extraction of cytotoxic compounds from C. citratus. CONCLUSIONS: It was demonstrated that C. citratus ethyl acetate and chloroform fractions, essential oil, as well citral and geraniol were considered toxic to A. salina, cytotoxic to human blood cells and showed to induce alterations in the erythrocyte membrane at higher concentrations. These fractions will be further investigated to identify the phytochemicals involved in the observed cytotoxic effects and explored using in vivo models.

Comparison of two methodologies for CD4⁺ T lymphocytes relative counting on immune monitoring of patients with human immunodeficiency virus.

Considering that counting the percentage of CD4 T lymphocytes can add prognostic information regarding patients infected with HIV, the aim of this study was to evaluate the percentage values of CD4⁺ T lymphocytes from 81 patients determined by flow cytometry and estimated by flow cytometry in conjunction with a hematology counter. Means were compared through the Student's t-test. Pearson's correlation was determined, and the agreement between results was tested by Bland-Altman. The level of significance was P < 0.05. It was found a significantly higher mean difference between the relative values of CD4⁺ T lymphocytes to the hematologic counter (P < 0.05), for all strata studied. Positive and significant correlations (P < 0.01) were found between the strata CD4 < 200 cells/mL (r = 0.93), between 200 and 500 cells/mL (r = 0.65), and >500 cells/mL (r = 0.81). The limits of agreement were 1.0 ± 3.8% for the stratum of CD4 < 200 cells/mL, approximately 2.2 ± 13.5% for the stratum of CD4 between 200 and 500 cells/mL, and approximately 6.2 ± 20.4% for the stratum > 500 cells/mL. The differences in the percentages of CD4⁺ T lymphocytes obtained by different methodologies could lead to conflict when used in clinical decisions related to the treatment and care of people infected with HIV.