Potency of Combining Eucalyptus camaldulensis subsp. camaldulensis with Low-Dose Cisplatin in A549 Human Lung Adenocarcinomas and MCF-7 Breast Adenocarcinoma

Background: Lung and breast cancers are common in the world and represent major public health problems. Systemic chemotherapy is an effective way to prolong survival but it is associated with side effects. Plants are used as traditional treatments for many types of cancers, mostly in combination with chemotherapy. We investigated the antitumor effect of ethanolic (EE) and aqueous (AE) extracts of Eucalyptus camaldulensis on human alveolar adenocarcinoma basal epithelial cells (A549) and breast adenocarcinoma cell line (MCF-7) and checked the synergistic effect of the combination with low-dose cisplatin (CDDP). Methods: AE and EE were characterized for their secondary metabolites including content of phenol and antioxidant activity of both extracts. Cell viability was tested by the neutral red assay and MTT. Combinations of extract with low-dose CDDP on A549, MCF-7 cells, and normal cells peripheral blood mononuclear cells was used to study cell viability. Results: AE contains higher level of active constituents than EE. Higher antioxidant activity was observed in AE. Both extracts showed cytotoxic activity on A549 and MCF-7 cells. Moreover, combining E. camaldulensis with low-dose CDDP increases significantly the cell death of treated cells in comparison to those treated with CDDP alone. Conclusions: Our results highlight a new therapeutic concept that combines Eucalyptus camaldulensis with low-dose CDDP to treat lung and breast adenocarcinoma.

Keywords: antioxidant activity; antitumor effect; cell viability; cisplatin; eucalyptus; phenol content.