Biogenic Silver Nanoparticles of Clinacanthus nutans as Antioxidant with Antimicrobial and Cytotoxic Effects.

Hock Ing Chiu,Noorfatimah Yahaya,Muggundha Raoov Ramachandran,Wai Hau Tung,Vuanghao Lim,Chee Keong Lee,Yoke Keong Yong,Che Nurul Azieyan Che Mood,Nik Nur Syazni Nik Mohamed Kamal,Nur Nadhirah Mohamad Zain,Giuseppe Ciccarella

doi:10.1155/2021/9920890

Hock Ing Chiu, Noorfatimah Yahaya + Show 9 more

Open Access

https://doi.org/10.1155/2021/9920890

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Abstract

Silver nanoparticles (AgNPs) previously synthesised using leaf (AgNP-L) and stem (AgNP-S) extracts of Clinacanthus nutans (C. nutans) were tested to evaluate antimicrobial, antioxidant, and cytotoxicity activities. The AgNPs showed good inhibition against bacteria, but not fungi. The inhibition results showed the highest activity against Staphylococcus aureus (S. aureus) with 11.35 mm (AgNP-L) and 11.52 mm (AgNP-S), while the lowest inhibition was against Escherichia coli (E. coli) with 9.22 mm (AgNP-L) and 9.25 mm (AgNP-S) in the disc diffusion method. The same trend of results was noted in the well diffusion method. The IC50 of AgNP-L and AgNP-S in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays was 417.05 μg/mL and 434.60 μg/mL, as well as 304.31 μg/mL and 326.83 μg/mL, respectively. Ferric reducing power (FRAP) assay showed that AgNP-L [872.389 μmol/L Fe(II)] and AgNP-S [612.770 μmol/L Fe(II)] exhibited significantly (p < 0.05) greater antioxidant activities than leaf extract (CNL) [152.260 μmol/L Fe(II)] and stem extract (CNS) [110.445 μmol/L Fe(II)] of C. nutans. The AgNPs were also proven to possess cytotoxic effects on the breast (MCF-7), cervical (HeLa), and colon (HT-29) cancer cells in a dose-dependent manner. AgNP-S and AgNP-L showed significantly (p < 0.05) higher cytotoxicity against MCF-7 (117.43 μg/mL) and HT-29 (78.47 μg/mL), respectively. In conclusion, the biosynthesised AgNPs from aqueous extract leaves and stem of C. nutans have demonstrated promising potential towards antioxidant, antimicrobial, and cytotoxicity activities.

Highlights

AgNPs are well known as effective antimicrobial agents against bacteria and fungi [1,2,3,4]. erefore, they have been studied in bacterial applications, for instance, in the medical, cosmetics, food, and textile industries [5,6,7,8]
Based on the findings shown, both AgNP-L and AgNPS have produced higher cytotoxicity effects compared to plant extracts (CNL and CNS). e antiproliferative activities are categorised into four groups according to the values of IC50: ≤20 μg/mL, >20–100 μg/mL, >100–1000 μg/mL, and >1000 μg/mL [58]
The results indicate that AgNPs have cytotoxic effects against the cancer cell lines of MCF-7, HT-29, and HeLa

Summary

Introduction

AgNPs are well known as effective antimicrobial agents against bacteria and fungi [1,2,3,4]. erefore, they have been studied in bacterial applications, for instance, in the medical, cosmetics, food, and textile industries [5,6,7,8]. AgNPs are well known as effective antimicrobial agents against bacteria and fungi [1,2,3,4]. Due to the development of antibiotic resistance, researchers are keen to identify alternatives in the development of new antibacterial agents. Side effects have been observed in synthetic antioxidants such as butylated hydroxytoluene (BHT) and hydroxyanisole (BHA). Several studies reported significant antioxidant activity of the C. nutans extract [12, 13]. Us, the biocompatible C. nutans-derived AgNPs could be an alternative for synthetic antioxidants. A previous study reported that the synthesised AgNPs using Costus afer aqueous leaf extract showed higher antioxidant activity compared to the leaf extract only [16]. AgNPs may, be a new/novel antioxidant agent with the ability to avoid side effects exhibited by synthetic antioxidants

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