# In Vitro Assessment of Apoptotic and Cell Cycle Arrest Analysis on HepG2 Cells by Polyethylene Glycol–Coupled Selenium Nanocomposite Fabricated From Cassia fistula Flowers

## TL;DR

A selenium nanocomposite made from Cassia fistula flowers and polyethylene glycol shows strong anticancer effects on HepG2 liver cancer cells.

## Contribution

A novel PEG-coupled selenium nanocomposite from Cassia fistula flowers is developed and tested for its anticancer properties.

## Key findings

- CFF-SeNC showed 50% cell inhibition (IC50) at 27.30 μg/mL in HepG2 cells.
- The nanocomposite induced apoptosis and cell cycle arrest in HepG2 cells.
- CFF-SeNC exhibited strong antioxidant and anti-inflammatory properties.

## Abstract

Polymer-encapsulated nanocomposite has been proven to have ameliorative effects in the treatment of cancer. The focused objective of the present research is to fabricate polyethylene glycol (PEG)–based Cassia fistula flower selenium nanocomposite (CFF-SeNC). The fabricated CFF-SeNC was characterised using a UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM)–energy dispersive x-ray (EDX), and x-ray diffractometer (XRD) analysis. The highest UV-visible absorption spectra were at 355 nm. The oval-shaped, less agglomerated nanocomposite with a rough surface was seen in the SEM results with the elemental composition of carbon, oxygen, and selenium. The XRD analysis results showed the crystalline form of CFF-SeNC. The potency of CFF-SeNC against pathogenic bacteria and fungi proved that CFF-SeNC is effective against the tested fungi Candida albicans. The antioxidative assays—DPPH, ABTS, and H2O2 of CFF-SeNC—revealed the inhibition percent of 85.51% ± 0.79%, 90.53% ± 0.90%, and 84.87% ± 0.80% at maximum concentration (50 μg/mL), respectively. The anti-inflammatory efficiency of CFF-SeNC was found to be 80.61% ± 0.87% and 87.78% ± 0.88% by egg albumin denaturation and HRBCs (human red blood cells) membrane stabilisation assay. The biocompatible nature of CFF-SeNC was tested by brine shrimp lethality activity, which proved that at 48 h, the minimal dose was not toxic; however, mild toxicity was shown at a higher dosage. The anticancer studies of CFF-SeNC in HepG2 cells were active in inhibiting 50% of cells (IC50 value) at 27.30 μg/mL. HepG2 cells depicted predominant morphological changes upon treatment with CFF-SeNC, whereas there was no alteration in Vero cells. The elaborative study on determining the phases of cell apoptosis was further analysed by fluorescence microscopy, cell cycle arrest, and Annexin V/propidium iodide staining through flow cytometric analysis. The outcome of current research has corroborated the enhanced therapeutical efficiency of PEG-encapsulated selenium nanocomposite with emphasis on the apoptotic effect in hepatocellular carcinoma (HepG2 cells).