Research Paper: Immunomodulatory Effects of Origanum vulgare L. and Origanum Majorana L. Ethanolic Extracts in Vitro

Background: Many plants possess therapeutic properties against infectious and non-infectious diseases, including cancer and inflammatory diseases. Plants may have immunomodulatory properties, too. In this study, we evaluated the immunomodulatory effects and toxic properties of ethanolic extract from the Lamiaceae family on macrophage, lymphocyte, and B Cell Leukemia (BCL-1) in vitro. Materials and Methods: Plant samples were purchased, and the ethanolic extract from their leaves was prepared by dissolving them in ethanol (maceration) for 48 hours. The obtained ethanolic extract was dried at room temperature. The normal lymphocytes and macrophages extracted from BALB/c mice and BCL-1 were cultured with different concentrations of the extracts for 24 hours. MTT assay was performed to evaluate proliferation, and Lactic Dehydrogenase (LDH)-based cytotoxicity was measured. Results: We found that ethanolic extracts at a concentration of 1 mg/mL significantly increased lymphocyte proliferation (47% by Origanum vulgare and 95% by Origanum majorana compared to the control group). Also, the activity of macrophages increased 35% after O. vulgare administration and 23% after O. majorana administration at a dose of 1 mg/mL. Furthermore, LDH results prove that O. vulgare and O. majorana (1 mg/mL) had no toxic effect on normal lymphocytes and macrophages. The finding of the MTT assay showed that extracts of O. vulgare (with IC50 of 1.04 mg/mL) and O. majorana (with IC50 of 1.6 mg/mL) could significantly suppress the growth of BCL-1. Conclusion: The O. vulgare and O. majorana extract with immunomodulatory effects increased the proliferation and activities of lymphocytes and macrophages in a dose-dependent manner. Also, the tested extracts were showed significant anticancer activity.