INTRODUCTION AND OBJECTIVES: Lung cancer is, according to PAHO (Pan American Health Organization, 2018), the leading cause of cancer deaths among men and women (about 1.76 million deaths). It is divided into small cell lung cancer and non-small cell lung cancer. The latter, being one of the most frequent, affecting 80 to 85% of lung cancer patients. In addition, it is also the one with the highest mortality rate, commonly associated with smoking. This type of cancer can undergo metastasis affecting other organs. Among the treatments the most common is chemotherapy, patients however, have been presenting resistance to treatment, making the search for effective and alternative therapies necessary. Thus, the discovery of the antitumor potential of plants such as Manilkara Huberi can be a support for chemotherapy treatments with existing drugs or even alone. In this study, the antitumor activity of extracts of Manilkara Huberi, an Amazonian plant, using non-small cell lung cancer was evaluated in order to identify new alternatives to the treatment of non-small cell lung cancer. The extracts were obtained thanks to the partnership with Universidade Federal do Pará. MATERIAL AND METHODS: To analyze the in vitro antitumor activity of extracts, subfractions, called A7, P10 and MHF1, H460 cells were used. Treatment with the subfractions was accompanied by 3-methyladenine, an autophagy inhibitor. The cells were analyzed after 48 hours by fluorescence microscopy to detect ATG12 expression and flow cytometry for cell cycle analysis. RESULTS AND CONCLUSION: Vacuole formation was observed in cells treated with the subfractions, in addition, a statistically significant increase in the percentage of subG1 cells from the treatment with P10 and MHF1 with the inhibitor in relation to those with the extracts only, shows that the inhibitor may be inducing death by apoptosis in the cells. Samples with A7, on the other hand, although showing an increase when combined with the inhibitor, were not statistically significant. Also, the expression of ATG12 was not altered by 3-MA. To completely elucidate the mechanism of action of the extract and fractions, further studies are necessary.