Cytotoxic, colony formation and anti-migratory effects of Spilanthes acmella (Asteraceae) aerial extract on MCF-7 cells and its cream formulation

Abstract

Purpose: To determine anti-breast cancer activities of Spilanthes acmella (S. acmella) extract. Methods: S. acmella was macerated with 95% ethanol. Phenolic, flavonoid content and antioxidant activity of the extract were assessed using Folin Ciocalteu method, aluminum chloride (AlCl3) colorimetric method and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, respectively. Cytotoxicity, colony formation and cell migration suppression on MCF-7 cells, representing anti-breast cancer effects, were also evaluated by sulforhodamine B (SRB), clonogenic and wound healing assays, respectively. Creams containing the extract were formulated and then characterized in terms of their physical appearance, viscosity and pH, before and after stability testing. Results: The crude extract contained phenolic content of 62.8 ± 5.2 mg gallic acid equivalent/g and flavonoid content of 375.6 ± 20.1 mg rutin equivalent/g. The results showed that the extract exhibits antioxidant effect with half-maximal inhibitory concentration (IC50) of 1.2 ± 0.1 mg/mL. It showed cytotoxicity on MCF-7 cells with IC50 of 37.1 ± 1.1 µg/mL in 48 h and inhibited colony formation of cells with IC50 of 44.9 ± 1.3 μM. In addition, it demonstrated an anti-migration effect at a concentration of 50 µg/mL. The developed creams displayed good physical appearance and maintained stable physical properties overt a two-month period. Conclusion: S. acmella extract exhibits potential anti-breast cancer activity. The cream containing the extract is promising for the topical treatment of breast cancer.