Anticancer Properties of Secondary Metabolites Isolated from Lichen Parmelia vagans

Abstract

This study aims to analyze the antiproliferative properties of the secondary metabolites extracted from lichen Parmelia vagans collected from the semi‐deserts of Russia. Identification of novel natural compounds that can selectively slow down or stop proliferation of cancer cells can enhance development of anticancer therapeutics.Various lichen extracts were prepared using either water or organic solvents. We assessed the antiproliferative activity of the extracts against several human cancer cell lines; human malignant melanoma (A375), human mammary gland adenocarcinoma (MCF7). Human dermal fibroblasts (HDFa) were used as control. The same number of cells of different cell lines were plated into a 96‐well plate and allowed to adhere overnight in CO2 incubator. Different dilutions of the lichen extracts were added to the cell cultures next day, and the plate and incubated at 37°C for 6–72 hours. By the end of the incubation time a picture of each well was taken to assess cell confluency and morphology. To asses the effect of the lichen extracts on cell growth and proliferation we used a Resazurin assay. After Resazurin assay, the cells in each well were treated with trypsin, suspended in growth medium and counted using Bio‐Rad cell counter to evaluate a percent of live cells.Our experimental data from cell viability assay and live cells count indicate that ethyl acetate extracts of P.vagans significantly suppress (30% – 60%) the growth of human malignant melanoma but have a limited effect on human mammary gland adenocarcinoma. We also found that cancer cells subjected to lichen extract change their morphology, and these changes resemble an activation of apoptosis.Our findings indicate that Parmelia vagans extracts contain secondary metabolites that slow cancer cells growth and proliferation. Furthermore, the extracts affect cancer various cells differently, suggesting that the active compound(s) utilizes a distinct mechanism of action on different types of cancer. Future experiments will focus on the isolation and characterization of the compounds from P.vagans extracts that are responsible for the inhibition of cancer cell growth. Another important direction of future research is to identify the cellular target(s) of the antiproliferative compound(s) and its molecular mechanism of action. In summary, the lichen’s secondary metabolites may hold vast medicinal potential and could be a viable source of a novel of anticancer drugs.Support or Funding InformationThe funding for this project was provided by Touro University Nevada research grant.