Curcumin combined with photodynamic therapy, promising therapies for the treatment of cancer

1. Introduction

Curcumin, a plant-deprived curry spice, which is extracted from turmeric, has entered people's field of vision because of its recognized medicinal properties [1]. To date, a recent bibliographic search of the PubMed database identified 16,827 papers on curcumin (1987–2021), and of which 6, 148 papers on the both curcumin and cancer (1987–2021). However, the bioavailability of curcumin is limited due to its poor water solubility [2] and rapid metabolism [3], [4]. Furthermore, low absorption rate [3], easy decomposition and interference with other drugs [5] have also become obstacles to the clinical application of curcumin [6], [7]. Therefore, in the past few decades, researchers have developed different strategies to improve the bioavailability of curcumin.

Photodynamic therapy (PDT), a modern and non-invasive form of therapy [8], has been successfully used in dermatology, oncology, gynecology and urology [9]. This therapy is based on the local or systemic application of the photosensitizer, which can intensely accumulate in pathological tissues. Photosensitizer was excited at the target location by appropriate wavelength light radiating, which subsequently generating a series of biochemical reactions and inducing cell death and damaging diseased tissues. Due to its advantages of non-invasion and safety, PDT has been widely applied in the treatment of skin diseases (such as: acne, psoriasis, dermatitis, in vitro sterilization) , . Meanwhile, PDT, as an auxiliary method for the treatment of cancer, has proved to be effective in various types of cancer cells . Numerous studies indicating the use of PDT in oncology have been greatly improve the anticancer efficacy of curcumin over last several decades. In this review, we focus on the structures, metabolites of curcumin, and highlight the recent advances in anticancer activity of curcumin combined with PDT, with an emphasis on the potential mechanism involved in apoptosis and signal pathways.

2. Curcumin