Plant extracts as natural photosensitizers in photodynamic therapy: in vitro activity against human mammary adenocarcinoma MCF-7 cells

Abstract

Objective: To examine three plant extracts [Lumnitzera racemosa (Combretaceae) (L. racemosa), Albizia procera (Fabaceae) (A. procera) and Cananga odorata (Annonaceae)] for their potential as source of photosensitizers in photodynamic therapy. Methods: Human mammary adenocarcinoma (MCF-7) cells were treated with the plant extracts, which were irradiated with 5.53 mW and 0.553 mW broadband light. Cell viability was assessed using MTT assay and induction of apoptosis was determined using terminal deoxynucleotidyl transferase-dUTP nick end labeling assay. Results: The crude ethanolic extracts, independently, were nontoxic against cancer and non-cancer cells but when irradiated with 5.53 mW broadband light, L. racemosa and A. procera extracts were cytotoxic against MCF-7 with IC50 of 11.63 μg/mL and 10.73 μg/mL, respectively. With 0.553 mW broadband light, the IC50 values were higher at 17.14 μg/mL and 19.59 μg/mL, respectively. Photoactivated L. racemosa and A. procera extracts were found to be more cytotoxic against MCF-7 than the non-cancer cell line, human dermal fibroblast-neonatal. Moreover, the cytotoxicity of the extracts was mediated by apoptosis. Conclusions: Two of the plant extracts used, L. racemosa and A. procera were toxic and induced apoptosis to mammary cell adenocarcinoma, MCF-7 when photoactivated. These extracts were also more toxic to human cancer than non-cancer cell lines.

Keywords

• Photodynamic therapy
• MCF-7
• Photosensitizer
• Lumnitzera racemosa
• Albizia procera
• Cananga odorata