Methanol Extract of Pueraria lobata (Willd.) Root and Its Active Ingredient, Puerarin, Induce Apoptosis in HeLa Cells and Attenuates Bacterial Vaginosis in Gardnerella vaginalis-Infected Mice

Pueraria lobata (Willd.) has been used as food since ancient times, and its roots have been used mainly as a traditional herbal medicine to treat various diseases in East Asia. Puerarin is one of the major active ingredients in the roots of P. lobata. The purpose of this study was to examine the effects of the methanol extract of P. lobata roots (PRME) and puerarin on apoptosis in cervical cancer and inflammation-relieving effects in vaginitis. First, we prepared the PRME and confirmed the puerarin content of PRME through HPLC analysis. We performed a TUNEL assay, Hoechst 33342 staining, and western blotting using HeLa cells, a human cervical cancer cell line. Both the PRME and puerarin exhibited antiproliferative effects in HeLa cells by inducing apoptosis through the activation of the extrinsic death receptor and intrinsic mitochondrial pathways, thereby demonstrating their anticancer efficacy against human cervical cancer. Next, a mouse model of vaginitis induced by Gardnerella vaginalis (GV) infection was established by inoculating C57BL/6 mice with β-estradiol-3-benzoate and GV (1 × 108 CFU). Histological analysis and PCR confirmed that the administration of PRME or puerarin to GV-infected mice alleviated reproductive tract vaginitis symptoms. Additionally, we confirmed that PRME or puerarin treatment decreased myeloperoxidase activity and reduced inflammation by regulating cytokines through the secretion of inflammatory mediators in mouse vaginal tissue. These results demonstrate that PRME and puerarin can be used as potential adjuvants or therapeutic agents with anticancer and anti-inflammatory properties to inhibit the progression of human cervical cancer and alleviate vaginitis.