Biofabrication of silver nanoparticles from aqueous leaf extract of Leucas aspera and their anticancer activity on human cervical cancer cells

Raviteja Chavata, Sumathy Datchanamurthy and Venkatesan Kotteeswaran

Abstract

The cancer treatments including chemotherapy, radiotherapy and other methods are effective in controlling cancer cells. However, their side effects are growing concerns to society. Application of nanotechnology in medicine may increase the effectiveness of the treatment. In this study, the silver nanoparticles were synthesised naturally from aqueous leaf extract of the Leucas aspera and their anticancer activity was investigated. Though, several studies were published on the effect of Leucas aspera nanoparticles on cancer cell lines, the in-depth study of anticancer activity of Leucas aspera nanoparticles was not investigated. Therefore, the present research work studied the characterisation and anticancer activity of Leucas aspera nanoparticles using HeLa cells as cancer cell model. The synthesis of silver nanoparticles was morphologically represented by change of colour from golden yellow to dark brown and also UV–visible spectral analysis provided a characteristic surface absorption peak at 450 nm. In addition to this, the size and surface charge of the nanoparticles were measured by zeta potential analyser, where the size was depicted to be 200 nm and zeta potential as −55.1 mV. Furthermore, Fourier transform infrared spectroscopy (FTIR) showed three intense peaks at 3343.705 cm⁻¹, 1636.668 cm⁻¹ and 668.336 cm⁻¹ confirming the presence of flavonoids and polyphenols. Then, the SEM analysis with EDS showed the shape and size of the nanoparticles were round and 50 nm respectively. The cytotoxicity of the nanoparticles was determined by LDH assay, where 100 μg ml⁻¹ of nanoparticles showed 50% of cytotoxicity and DNA fragmentation assay also denotes the death of the cells is through the induction of apoptosis. Furthermore, cell cycle analysis confirmed anticancer activity by showing 94.2% apoptotic cells during analysis. In summary, nanoparticles were proven to exhibit potent cytotoxic effect on cervical cancer cells and induce cell death through apoptosis. Since, the nanoparticles have exhibited cytotoxicity on the cancer cells; further investigation is required to understand their intracellular interaction.