Background: Rosin (Colophony) is a natural resin derived from species of the pine family Pinaceae.
It has wide industrial applications including printing inks, photocopying paper, adhesives and varnishes, soap
and soda. Rosin and its derivatives are employed as ingredients in various pharmaceutical products such as
ointments and plasters. Rosin-based products contain allergens that may exert some occupational health problems
such as asthma and contact dermatitis.
Objective: Our knowledge of the pharmaceutical and medicinal properties of rosin is limited. The current study
aims at investigating the cytotoxic potential of Rosin-Derived Crude Methanolic Extract (RD-CME) and elucidation
of its mode-of-action against breast cancer cells (MCF-7 and MDA-MB231).
Methods: Crude methanol extract was prepared from rosin. Its phenolic contents were analyzed by Reversed-
Phase High-Performance Liquid Chromatography (RP-HPLC). Antioxidant activity was evaluated by DPPH
radical-scavenging assay. Antiproliferation activity against MCF-7 and MDA-MB231 cancerous cells was investigated
by MTT assay; its potency compared with doxorubicin as positive control and specificity were assessed
compared to two non-cancerous cell lines (BJ-1 and MCF-12F). Selected apoptosis protein markers were
assayed by western blotting. Cell cycle analysis was performed by Annexin V-FITC/PI FACS assay.
Results: RD-CME exhibited significant and selective cytotoxicity against the two tested breast cancer cells
(MCF-7 and MDA-MB231) compared to normal cells as revealed by MTT assay. ELISA and western blotting
indicated that the observed antiproliferative activity of RD-CME is mediated via the engagement of an intrinsic
apoptosis signaling pathway, as judged by enhanced expression of key pro-apoptotic protein markers (p53, Bax
and Casp 3) relative to vehicle solvent-treated MCF-7 control cells.
Conclusion: To our knowledge, this is the first report to investigate the medicinal anticancer and antioxidant
potential of crude methanolic extract derived from colophony rosin. We provided evidence that RD-CME exhibits
strong antioxidant and anticancer effects. The observed cytotoxic activity against MCF-7 is proposed to take
place via G2/M cell cycle arrest and apoptosis. Colophony resin has a great potential to join the arsenal of plantderived
natural anticancer drugs. Further thorough investigation of the potential cytotoxicity of RD-CME
against various cancerous cell lines is required to assess the spectrum and potency of its novel activity.