Gallic acid enhancement of gold nanoparticle anticancer activity in cervical cancer cells

Cervical cancer (CxCa) is the most common cancer in women and a prominent cause of cancer mortality worldwide. The primary cause of CxCa is human papillomavirus (HPV). Radiation therapy and chemotherapy have been used as standard treatments, but they have undesirable side effects for patients. It was reported that gallic acid has antioxidant, antimicrobial, and anticancer activities. Gold nanoparticles are currently being used in medicine as biosensors and drug delivery agents. This study aimed to develop a drug delivery agent using gold nanoparticles conjugated with gallic acid. The study was performed in uninfected (C33A) cervical cancer cells, cervical cancer cells infected with HPV type 16 (CaSki) or 18 (HeLa), and normal Vero kidney cells. The results showed that GA inhibited the proliferation of cancer cells by inducing apoptosis. To enhance the efficacy of this anticancer activity, 15-nm spherical gold nanoparticles (GNPs) were used to deliver GA to cancer cells. The GNPs-GA complex had a reduced ability compared to unmodified GA to inhibit the growth of CxCa cells. It was interesting that high-concentration (150 μM) GNPs-GA was not toxic to normal cells, whereas GA alone was cytotoxic. In conclusion, GNPs-GA could inhibit CxCa cell proliferation less efficiently than GA, but it was not cytotoxic to normal cells. Thus, gold nanoparticles have the potential to be used as phytochemical delivery agents for alternative cancer treatment to reduce the side effects of radiotherapy and chemotherapy.