Background: Breast cancer is the most leading cause of death, with 49.9% of crude incidence rate
and 12.9% of crude mortality rate. Natural resources have been extensively used throughout history for better
and safer treatment against various diseases.
Objectives: The present study was aimed to investigate the antioxidant and anticancer potential of a tropical
lichen Dirinaria consimilis (DCME) and its phytochemical analysis.
Methods: The DCME was preliminarily evaluated for ROS, and RNS scavenging potential. Furthermore,
DCME was evaluated for in vitro anticancer activity through cell proliferation assay, cell cycle analysis, annexin
V/PI staining, morphological analysis, and western blotting study. Finally, the HPLC and LC-MS analyses were
done to identify probable bioactive compounds.
Results: The in vitro antioxidant studies showed promising ROS, and RNS scavenging potential of DCME.
Moreover, the in vitro antiproliferative study bared the cytotoxic nature of DCME towards MCF-7 (IC50 - 98.58
± 6.82μg/mL) and non-toxic towards WI-38 (IC50 - 685.85 ± 19.51μg/mL). Furthermore, the flow-cytometric
analysis revealed the increase in sub G1 population as well as early apoptotic populations dose-dependently. The
results from confocal microscopy showed the DNA fragmentation in MCF-7 upon DCME treatment. Finally, the
western blotting study revealed the induction of tumor suppressor protein, p53, which results in increasing the
Bax/Bcl-2 ratio and activation of caspase-cascade pathways.
Conclusion: The activation of caspase-3, -8, -9 and PARP degradation led us to conclude that DCME induces
apoptosis in MCF-7 through both intrinsic and extrinsic mechanisms. The LC-MS analysis showed the presence
of various bioactive compounds.