Investigation of the antiproliferative, apoptotic and antioxidant effects of plant extracts of avocado (Persea americana) and melissa (Melissa officinalis) on breast cancer cell line (MCF-7)

Breast cancer is one of the most frequently diagnosed cancer types in women in the world and in our country. It is known that it is the second leading death of cause in women worldwide. Therefore, many different studies are conducted on the treatment of breast cancer. Complementary treatments are among the preferred methods in addition to chemotherapy and radiotherapy applications. In this thesis, it was aimed to determine the antiproliferative, apoptotic and antioxidant effects of using melissa and avocado extracts in breast cancer cell line (MCF-7). The main target of chemotherapeutic agents applied for treatment in medicine is to destroy neoplastic cells. However, some healthy cells may also be adversely affected by the application, and as a result various side effects may occur. As reported in the literature, melissa and avocado plants have strong antioxidant properties with the components they contain. The antioxidant properties of these plants are important in terms of reducing the side effects of drugs used in cancer treatments and at the same time reducing the level of reactive oxygen species (ROS). The main purpose of the thesis is to reveal the antiproliferative, apoptotic and antioxidant effects of melissa and avocado plants on cancer cell lines (MCF-7) and to contribute to the literature for complementary therapy. In the study, different concentrations of melissa and avocado plant extracts (1 µg/mL, 10 µg/mL, 100 µg/mL and 1000 µg/mL) were applied to the MCF-7 cell line. Cytotoxic activities were determined using the MTT method in 24 hours, and apoptotic activities were determined the annexin V method using. Determination of the biochemical parameters, 1 µg/mL, 10 µg/mL, 100 µg/mL and 1000 µg/mL doses were applied to the cells and then cell lysates were obtained. Firstly, the protein level of the cell was calculated with the prepared samples. Then, TOS, TAS, OSI, SOD, GPx activity determination, MDA and NO analyzes were made. When the results were evaluated in our study, it was determined that melissa and avocado plant extracts decreased MCF-7 cell proliferation depending on dose and time. At the same time, the increase in apoptosis also explains this proliferation inhibition. The antioxidant results that came out within the framework of the research also support the inhibition of proliferation and also the increase of apoptosis. When all statistical data are evaluated, it has been determined by the current research that the molecular anticarcinogenic mechanisms of melissa and avocado plants in MCF-7 cells will be studied individually or in combination with chemotherapeutic agents, and will contribute significantly to the development of new chemotherapeutic and chemopreventive agents for breast cancer treatment.