Background and objective: Rosmarinic acid is considered as one of the most important secondary metabolites in medicinal plants especially of family Lamiaceae. Rosmarinic acid can prevent both the tumor initiation and promotion stages of carcinogenesis. The aim of current study was to evaluate the antiproliferative effects of Hyssopus officinalis and Thymus vulgaris callus crude extracts contained rosmarinic acid on breast cancer cells with correlation to phenylpropanoid biosynthetic pathway genes expression.
Materials and methods: Calli of both plants were maintained on Murashige and Skoog medium supplemented with kinetin and 2,4-D. Rosmarinic acid was determined spectrophotometrically in both seed-germinated plants (control) and callus tissues. Transcriptional profiling of rosmarinic acid pathway genes was performed with RT-PCR system. The human breast cancer cell line MCF-7 was treated with different levels of crude extracts at different time intervals in order to show their effects on the cell proliferation using a cell viability colorimetric assay (MTT).
Results: The results showed a significant increase of rosmarinic acid content up to 6.5% in callus compared to control. The transcriptional profile of the selected rosmarinic acid genes in callus tissues indicated significant effects on the rosmarinic acid content in both genotypes. T. vulgaris (90 μg mL-1) and H. officinalis (150 μg mL-1) callus extracts had exhibited highest reduction in the cell MCF-7 viability after 48 h of exposure.
Conclusion: It was concluded that rosmarinic acid production increased in callus tissue, showed the higher gene expression levels and remarkably inhibited growth of human breast cancer cell line.
Keywords: Lamiaceae; Rosmarinic acid; antiproliferative activity; breast cancer cell line; gene expression.