Multi-Biofunctional Properties of Phytofabricated Selenium Nanoparticles From Carica papaya Fruit Extract: Antioxidant, Antimicrobial, Antimycotoxin, Anticancer, and Biocompatibility.

Swetha Reddy Vundela,Naveen Kumar Kalagatur,Siddaiah Chandranayaka,Anusuya Nagaraj,Kasturi Kondapalli,Krishna Kadirvelu,Elsayed Fathi Abd_Allah,Abeer Hashem,Sudhakar Poda

doi:10.3389/fmicb.2021.769891

Abstract

The present study focused on phytofabrication of selenium nanoparticles (SeNPs) from Carica papaya extract and exploration of their multi-biofunctional features. Total phenolics and flavonoids of C. papaya fruit extract were determined as 23.30 ± 1.88 mg gallic acid equivalents and 19.21 ± 0.44 mg quercetin equivalents per gram, respectively, which suggested that C. papaya fruit extract could be a competitive reducing and stabilizing agent during phytofabrication of nanoparticles. UV–Vis and FTIR spectroscopy showed the formation of SeNPs from sodium selenite, which could be related to the reducing and stabilizing activities of C. papaya fruit extract. The SeNPs were found to be stable with a Zeta potential of −32 mV. The average hydrodynamic size of SeNPs was found as 159 nm by dynamic light scattering. The SeNPs showed a broader XRD pattern with no sharp Bragg’s peaks and found to be amorphous. SEM showed that SeNPs were spherical in shape and EDX pattern showed that SeNPs were made up of Se (71.81%), C (11.41%), and O (14.88%). The HR-TEM picture showed that SeNPs were spherical in morphology and have a size range of 101–137 nm. The SeNPs exhibited potent antioxidant activity and their EC50 values (effective concentration required to inhibit 50% of radicals) were 45.65 ± 2.01 and 43.06 ± 3.80 μg/ml in DPPH and ABTS assays, respectively. The antimicrobial action of SeNPs was found as a broad spectrum and suppressed microbial pathogens in ascending order: fungi > Gram-positive bacteria > Gram-negative bacteria. The SeNPs have been demonstrated to reduce the growth and ochratoxin A (OTA) of mycotoxigenic Aspergillus ochraceus and Penicillium verrucosum at 40 μg/ml in broth culture, which is noteworthy. The SeNPs reduced cancer cell proliferation (RAW 264.7, Caco-2, MCF-7, and IMR-32) more preferentially than normal cells (Vero), found to be highly biocompatible. Lower doses of SeNPs (up to 50 μg/ml) were shown to be less toxic and did not cause death in Danio rerio (zebrafish) embryos, implying that lower doses of SeNPs could be beneficial for biological purposes. The present study concluded that phytofabricated SeNPs have multiple biofunctional properties, including antioxidant, antimicrobial, antimycotoxin, and anticancer activities, as well as high biocompatibility.

Highlights

Nanotechnology is a cutting-edge field of research that involves regulating shape and size at the nanoscale (1–100 nm)
Green synthesis mediated selenium nanoparticles (SeNPs) have developed from C. papaya fruit extract in a low-cost, easier, and superior alternative to physical and chemical processes
FTIR analysis showed that SeNPs were synthesized as a result of effective interactions of functional groups of C. papaya fruit extract

Summary

INTRODUCTION

Nanotechnology is a cutting-edge field of research that involves regulating shape and size at the nanoscale (1–100 nm). Metabolites from plant extracts, including proteins, carbohydrates, flavonoids, phenolics, vitamins, tannins, alkaloids, saponins, potassium, iron, calcium, and other compounds, act as excellent reducing and stabilizing mediators compared with chemical and physical techniques to meet the growing interest for green SeNPs synthesis (Gunti et al, 2019; Menon et al, 2019; Matai et al, 2020). The focus of the research was to synthesize nanoparticles using Carica papaya fruit extract, which is environmentally safe, non-toxic, biocompatible, and affordable, and to investigate their biological capabilities, such as antioxidant, antimicrobial, antimycotoxin, and anticancer activities. Based on the beneficial features of C. papaya and high acceptability from consumers, aqueous extract of C. papaya fruit was used as a reduction and stabilization agent in the conversion of sodium selenite (precursor) to SeNPs. The phytofabricated SeNPs were characterized and investigated for their bioprospectus, including antioxidant, antimicrobial, antimycotoxin, anticancer, and biocompatibility. In the present study, biocompatibility of SeNPs was investigated using the in vivo model Danio rerio (zebrafish) in addition to their beneficial features

MATERIALS AND METHODS

AND DISCUSSION

CONCLUSION

ETHICS STATEMENT