Antitumour effects of the essential oil from Mentha x villosa combined with 5-fluorouracil in mice

In the previous study, we demonstrated that the essential oil from the leaves of Mentha x villosa (EOMV) shows antitumour activities. In the present paper, the effects of the combination of 5-fluorouracil (5-FU) with the EOMV were determined in mice transplanted with Sarcoma 180 tumour cells. Hematological and biochemical analyses, as well as morphological analyses of the tumour and the organs (liver, spleen and kidney) were performed in order to evaluate the toxicological aspects. The combination of the EOMV (50 and 100 mg/kg/day) with 5-FU (10 mg/kg/day) led to a higher tumour growth inhibition rate (58.9% and 65.7%, respectively) when compared with 5-FU alone at 10 mg/kg/day (30.2%). The combined use of 5-FU (10 mg/kg/day) with the EOMV (50 and 100 mg/kg/day) showed similar tumour growth inhibition rate to that of 5-FU alone at the highest dose (25 mg/kg/day) with less severe leukopenia. However, neither the enzymatic activity of transaminases nor the urea and creatinine levels were modified when compared with the 5-FU groups. These findings indicate that the EOMV may enhance the therapeutic effectiveness of chemotherapeutic drugs. Copyright © 2016 John Wiley & Sons, Ltd.