Ultrasound-assisted green synthesis of gold nanoparticles using citrus peel extract and their enhanced anti-inflammatory activity

• Published in: Ultrasonics sonochemistry Vol. 83; p. 105940
• Main Authors: Gao, Ling, Mei, Suhuan, Ma, Haile, Chen, Xiumin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2022; Elsevier
• Subjects: Anti-inflammation; Anti-Inflammatory Agents - pharmacology; AuNPs; Citrus; Citrus peel; Gold - chemistry; Gold - pharmacology; Green Chemistry Technology - methods; Green synthesis; Metal Nanoparticles - chemistry; Plant Extracts - chemistry; Plant Extracts - pharmacology; Short Communication; Spectroscopy, Fourier Transform Infrared; Ultrasonication; NO; COX-2; TPC; HRP; FT-IR; DLS; XRD; LPS; Anti-inflammation; NF-κB; IFN-γ; EDS; AuNPs; iNOS; Green synthesis; PGE-2; MT; AuNPs-U; Citrus peel; AuNPs-NU; IL-1β; MAPK; PVDF; IL-6; NPs; Ultrasonication; TNF-α; CPE; SEM; FE-TEM
• ISSN: 1350-4177; 1873-2828; 1873-2828
• DOI: 10.1016/j.ultsonch.2022.105940

[Display omitted] •Ultrasound decreased the size and distribution of AuNPs.•Ultrasound increased the yield and the anti-inflammatory activity of AuNPs.•AuNPs synthesized using citrus peel extract under ultrasound are stable.•The IC50 of AuNPs against nitric oxide was negatively correlated with ΔTPC.•Hesperidin is the major reductant in citrus peel extract for AuNPs synthesis. Ultrasound and plant extract are two green approaches that have been used to synthesize gold nanoparticles (AuNPs); however, how the combination of ultrasound and citrus peel extract (CPE) affects the structure characteristics and the bioactivity of AuNPs remains unknown. Here we investigated the effects of ultrasound conditions on the particle size, stability, yield, phenolic encapsulation efficacy, and the anti-inflammatory activity of AuNPs. The results showed that temperature was positively correlated to the particle size and the anti-inflammatory activity of synthesized AuNPs. Increasing the power intensity significantly decreased the particle size, while increased the change of total phenolic content (ΔTPC) in the reaction mixture. The increase of ΔTPC caused the enhanced anti-inflammatory activity of AuNPs. The AuNPs synthesized with or without ultrasound treatment were characterized using UV–Vis, DLS, SEM, TEM, EDS, XRD, and FT-IR. The result verified the formation of negatively charged, spherical, stable, and monodispersed AuNPs. AuNPs synthesized with ultrasound (AuNPs-U) has smaller particle size (13.65 nm vs 16.80 nm), greater yield and anti-inflammatory activity (IC50, 82.91 vs 157.71 μg/mL) than its non-ultrasound counterpart (AuNPs-NU). HPLC analysis showed that hesperidin was the key reductant for the synthesis of AuNPs. AuNPs-U also inhibited the mRNA and protein expression of iNOS and COX-2 in the LPS-induced Raw 264.7 cells. Our research elucidates the relationship between the reaction conditions and the structure characteristics and the anti-inflammatory activity of AuNPs synthesized using CPE with the help of ultrasound, thereafter, provides a feasible and economic way to synthesize AuNPs that can be used to ameliorate inflammation.