A Comparative Evaluation of the Antiproliferative Activity against HepG2 Liver Carcinoma Cells of Plant-Derived Silver Nanoparticles from Basil Extracts with Contrasting Anthocyanin Contents

Abstract

Nanotechnology is a well-established and revolutionized field with diverse therapeutic properties. Several methods have been employed using different reducing agents to synthesize silver nanoparticles (AgNPs). Chemical mediated synthetic methods are toxic and resulted in non-desired effects on biological systems. Herein, we, synthesized silver nanoparticles using callus extract of purple basil (BC-AgNPs) and anthocyanin extract deriving from the same plant (i.e. purple basil) (AE-AgNPs), and systematically investigated their antiproliferative potential against HepG2 Liver Carcinoma Cells. The phyto-fabricated AgNPs were characterized by different techniques like UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Energy dispersive X-rays (EDX). Morphologically, both types of NPs were found spherical. The average size of BC-AgNPs and AE-AgNPs as revealed through XRD and SEM analyses were calculated as 50.97 ± 0.10 nm and 42.73 ± 1.24 nm, respectively. FT-IR spectral analysis demonstrates the existence of possible phytochemicals required for the capping and reduction of Ag ions. Herein, following solid phase extraction (SPE) coupled to HPLC analysis, we report for the first-time the anthocyanin mediated synthesis of AgNPs and conforming the successful capping of anthocyanin. Small sized AE-AgNPs showed significant cytotoxic effect against human hepatocellular carcinoma (HepG2) cell line as compared to BC-AgNPs. Therefore, the results revealed that the prevalent group of flavonoids present in purple basil is the anthocyanins and AE-AgNPs could be employed as potential anticancer agents in future treatments strategies.

Keywords: Ocimum basilicum L. var. purpurascens; anthocyanin; characterization; cytotoxicity; silver nanoparticles.

Figure 1

(A) UV-Vis spectral analysis of BC-AgNPs; (B) UV-Vis spectral analysis of AE-AgNPs; (C) optical observation of green synthesized callus extract; (D) optical observation green synthesized anthocyanin extract.

Figure 2

XRD analysis of AgNPs: (A) XRD image of BC-AgNPs; (B) XRD image of AE-AgNPs.

Figure 3

(A) FT-IR image of BC-AgNPs (B) FT-IR image of AE-AgNPs.

Figure 4

SEM and EDX analysis of AgNPs where (A) SEM image of BC-AgNPs (B) SEM image of AE-AgNPs (C) EDX image of BC-AgNPs (D) EDX image of AE-AgNPs.

Figure 5

Cytotoxic effects of biologically synthesized AgNPs on HepG2 cells upon 24-h treatment with 200 µg/mL concentration. Untreated cells were included as controls. Microscopic images of HepG2 cells (treated and untreated). Magnification = 200×. (A) Image of BC-AgNPs cytotoxic activity; (B) image of AE-AgNPs cytotoxic activity; (C) image of Non-treated HepG2 cells; (D) percentage viabilities of cells relative to untreated control (Mean ± SD). Each sample was studied in triplicates (biological replicates), and the experiment was performed twice (technical replicates). * p ≤ 0.05 (two tailed t-test) when compared to NTC (non-treated cells).