Differential anti-proliferative effect on K562 leukemia cells of Lippia alba (Verbenaceae) essential oils produced under diverse growing, collection and extraction conditions

Lippia alba (Verbenaceae Family) is an aromatic shrub native to Latin America, with recognized medicinal properties and a well-known high phenotypical plasticity in response to environmental factors. In order to identify the parameters that potentiate its in vitro anti-proliferative effect on human leukemia cells (K562), a matrix was designed for the production of 76 essential oils (EOs) with variations in plant growing season, harvested part from the plant, and preservation and distillation material conditions. The results show that EOs obtained from the same L. alba chemotype (Citral or Carvone), but acquired under different environmental or extraction conditions, presented significant differences in their primary components, oil yield, and cytotoxic activity on K562 cells. Citral EOs produced under diverse conditions displayed a cytotoxic effect on tumour cells ranging from 54 to 95% (IS 1.8-8.6) and IC50 from 13 to 38.8 μg/mL. The differences in antiproliferative activity were significantly correlated with variations in the β-caryophyllene oxide concentration. These results show the value of using standardized production conditions for the commercial utilization of L. alba EOs.