Abstract
Breast cancer has been recorded as the second leading type of cancer with 2.3 million new
cases and 670 000 deaths in 2022. Over time conventional breast cancer treatments such as
surgery, radiation therapy, chemotherapy, and hormone therapy, have become less effective due to
severe side effects and multidrug resistance. Adopting a complementary and/or alternative
treatment strategy can be a significant solution to overcome such limitations. Exploring the
potential of an alternative treatment modality like Photodynamic Therapy (PDT) in using naturally
derived photosensitizers (PSs) can prove to be a promising anticancer strategy against breast
cancer. Several natural products have been used in traditional medicine throughout history for
different ailments with success. The diversity of plants, their beneficial primary and secondary
phytocompounds make them advantageous as cost-effective cancer treatment strategy with
minimal induced side effects. This study aims to demonstrate the phototoxic potential of naturally
derived photosensitizers (PS) pheophorbide-a and hypericin to treat MCF-7 breast cancer cells.
Hypericin and pheophorbide-a mediated PDT at 0.01 – 0.2 and 0.1 – 1.2 M at 1 J/cm2 fluency
with 595 nm and 660 nm laser irradiation used to treat MCF-7 cells. Post treatment cellular
responses were evaluated using 3-(4,5-dimethyl-2- thiazyl)-2,5-diphenyl-2H-tetrazolium bromide
(MTT) assay, morphological analysis, and flow cytometry (Annexin V/PI). Results showed that
both PSs showed significant phototoxic effects on MCF-7 cells via induction of apoptosis and
further in vivo investigation is a viable option.