31 J. Cosmet. Sci., 74, 31–43 (January/February 2023) *Address all correspondence to Wisanu Thongchai, wisanuthongchai@psru.ac.th Silver Nanoparticles of Bee Honey: Antioxidant and Antimicrobial Activities WISANU THONGCHAI Faculty of Science and Technology, Pibulsongkram Rajabhat University, Phitsanulok, Thailand (W.T.) Accepted for publication May 02, 2023. Synopsis In the present study, silver nanoparticles were synthesized from aqueous silver nitrate solution using bee honey and screening the activity of the synthesized nanoparticles against microorganisms. The antioxidant properties of bee honey silver nanoparticles and serum formulations were investigated. The antioxidant and antibacterial properties of aqueous solution of bee honey have been studied using 2.2-dipheny-1-picrylhydrazyl assay and ferric reducing/antioxidant power assay and an agar well diffusion method, respectively. Bee honey was used in bioreduction of silver nitrate to nanoparticles. Ultraviolet (UV)–visible spectrum of silver nanoparticles was found to be 500 nm, and functional groups from Fourier transform infrared spectroscopy from bee honey such as hydroxyl, carboxyl, carbonyl, and phenol groups were important groups in the bioreduction and incorporation of silver ions into nanoparticles. The particle size analysis of the silver nanoparticles was 273 nm in size. The formulated serums were stable and cosmetically appealing with satisfactory pH and viscosity. The bee honey silver nanoparticles and their serum formulation exhibited strong antioxidant and antibacterial activities. The bee honey silver nanoparticles were exhibited with strong antioxidant and antibacterial activities compared to bee honey. In this study, it can be concluded that the serum formulation containing 2% bee honey silver nanoparticles is stable with preferred homogeneity and pH value. INTRODUCTION Bee honey is a natural sweetener liquid that is widely used in various applications where it contains nearly 200 chemical compounds that include carbohydrates such as fructose and glucose (1). Bee honey is a supersaturated sugar solution that contains minerals, proteins, amino acids, vitamins, and nutrients. Part of the dry matter in bee honey contains sugar, which is responsible for its natural composition, viscosity, hygroscopicity, and energy (2). However, the content of bee honey varies depending on the type of plant and the nectar eaten by the bee. Scientific reports have shown that bee honey exhibits important biochemical functions, such as alleviating rhinitis, tonsillitis, and strengthening the immune system (3). Many researchers have confirmed that bee honey is useful in the treatment of wounds, burns, ulcers, and as a healing agent (4). Numerous studies have shown the superiority

32 JOURNAL OF COSMETIC SCIENCE of bee honey in comparison to many antioxidants and antibiotics. Bee honey has a strong antibacterial effect against pathogenic and nonpathogenic microorganisms, fungi, and yeasts, even in those who are initially resistance to many antibiotics (5). Nanobiotechnology has contributed significantly to the development of a new generation of antimicrobials used to fight antimicrobials, using silver nanoparticles due to their specific characteristics, such as penetration, contact, and microorganism specificity (6). Biological materials are used instead of harsh reagents in the synthesis of nanoparticles in an attempt to obtain dynamic conditions that allow for their use in biological applications. In such cases, syntheses are termed “green syntheses” (7). The current study therefore aimed to synthesize and characterize antimicrobial activity in silver nanoparticles (AgNPs) that have been reduced and stabilized with bee honey and incorporated into serum formulation, followed by testing for its antimicrobial activity against Staphylococcus aureus. METHODS GENERAL EXPERIMENTAL PROCEDURES All chemicals were in the process of analytical grade and were used as received without further purification. Ultrapure water (resistivity not less than 18.2 MΩ cm at 298 K) from the Milli-Q water purification system (MilliporeSigma, Burlington, MA, USA) was used in all tests. Ethanol, 2.2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,4,6-tripyridyl- s-triazine (TPTZ), and butylated hydroxytoluene (BHT) were purchased from Sigma- Aldrich Corporation (St. Louis, MO, USA) and Folin–Ciocalteu reagent was purchased from Merck (Darmstadt, Germany). Silver nitrate (AgNO 3 ),ferrous sulfate heptahydrate (FeSO 4 .7H 2 O), iron (III), and chloride (FeCl 3 )were the catalysts for analysis. All were provided by Merck. Glycerin. Tween 80 and poly (ethylene glycol) were all purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). The following instruments were used: spectrophotometer (UVmini-1240, Shimadzu Scientific Instruments, Columbia, MD, USA) used to scan the spectra of the sample pH meter (model pH 900, Precisa, Dietikon, Switzerland) water bath and shaker (model SB-1000, Eyela, Japan) Ultrasonicator (model 889, Cole-Parmer, Vernon Hills, IL, USA) rotary evaporator (EYELA N-1200B series, Eyela, Bohemia, NY, USA polytron (PT-MR 3000, Kinematica AG, Malters, Switzerland) and high-pressure homogenizer (EmulsiFlex-C3, Avestin, Ottowa, Canada). The Fourier transform infrared (FTIR) spectra were performed using a Nicolet iS5 FTIR spectrometer (Thermo Scientific, Waltham, MA, USA) it was operated in the range of 4,000 to 400 cm−1. PREPARATION OF BEE HONEY MATERIAL In this study, three samples of bee honey were randomly obtained from local markets around Thailand. The samples (A, B, and C) were bee honey from longan flowers, wildflowers, and benjaphan flowers, respectively. PHYSICOCHEMICAL ANALYSIS OF BEE HONEY Each bee honey sample had undergone some physicochemical analyses by Bogdanov et al. (8). Water content was expressed in percentage, using a refractometer for measuring