Biosynthesis of silver nanoparticles using <i>Citrus hystrix</i> leaf extract and evaluation of its anticancer efficacy against HeLa cell line

Cervical cancer continues to be the leading cause of death worldwide despite the availability of many therapeutic options. Biogenic synthesis of metal nanoparticles paves a new way for the development of targeted drug delivery modalities of cancer therapeutics.In this study, we demonstrate the efficacy of biosynthesized silver nanoparticles from methanolic leaf extract of Citrus hystrix as an anticancer agent used against cervical cancer cell line HeLa.The addition of 1 mM silver nitrate to methanolic leaf extract of Citrus hystrix resulted in the biosynthesis of silver nanoparticles during the reaction mixture and was incubated in the dark for 1 h at pH 9 with gentle stirring. Characterization of synthesized NPs was carried out using various analyses. MTT assay, DAPI, AO/EB double staining, and reverse transcriptase-PCR (RT-PCR) analysis were carried out to evaluate the cytotoxic activity of Citrus hystrix mediated green synthesized silver nanoparticles (ChAgNPs).The absorption band at 430 nm, as shown by UV-vis spectroscopy revealed the formation of AgNPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis shows that most of the ChAgNPs were spherical in shape and X-ray diffraction (XRD) patterns revealed the crystalline nature of the particles. Moreover, its potent cytotoxic effect on the HeLa cell line was analyzed using MTT assay with an IC50 value of 56 µg/ml by decreasing the cell viability in a dose and time-dependent manner. The induced apoptotic activity was confirmed by DAPI and double staining methods. Autophagic and apoptotic mediated cell death in ChAgNPs treated HeLa cell line was confirmed by staining procedures and RT-PCR methods.