Anti-bacterial and biocompatibility properties of green synthesized silver nanoparticles using Parkia biglandulosa (Fabales:Fabaceae) leaf extract Anjali John a , Anju Shaji a , Krishnakumar Velayudhannair b , Nidhin M a, * , Ganesan Krishnamoorthy c a Department of Chemistry, CHRIST (Deemed to be University), Hosur Road, Bengaluru, 560 029, Karnataka, India b Department of Life Sciences, CHRIST (Deemed to be University), Hosur Road, Bengaluru, 560029, Karnataka, India c Natural Products Chemistry Groups, Chemical Science & Technology Division, CSIR-North East Institute of Science & Technology (NEIST), Jorhat, 785 006, Assam, India ARTICLE INFO Keywords: P. biglandulosa Silver nanoparticles Antibacterial activity Biocompatibility B. cereus ABSTRACT The biosynthesis of silver nanoparticles is considered to be a feasible, green, and eco-friendly method. Silver nanoparticles (AgNPs) were synthesized using badminton ball tree (Parkia biglandulosa) leaf extract and their significant physiochemical properties were characterized. The aqueous extract of the leaf of P. biglandulosa act as a reducing as well as capping agent for the reduction of Ag þ ions. FTIR analysis was conducted to find out the compounds that were liable for the bio-reduction of silver ions and to study the functional groups present in P. bigalandulosa leaf extract. The biologically reduced silver nanoparticles showed a surface plasmon resonance at 439 nm as studied from the UV–visible absorption spectrum. TEM studies confirmed the shape of the nano- particles to be spherical with an average diameter of 15 nm. The anti-bacterial properties of the prepared nanoparticles were tested against Bacillus cereus by well plate method. Biosynthesized silver nanoparticles (PbAgNPs) at 0.02 M concentration showed the most antibacterial activity with a zone of inhibition of 7 mm. The high biocompatibility of the PbAgNPs by using human skin fibroblast cell line was evaluated by Alamar Blue reduction assay. The PbAgNPs had shown the highest cell viability when compared to native nanoparticles, meanwhile, a significant increase in cell viability was noted for the nanoparticles. The biosynthetic approach for synthesis was found to be a facile, rapid, single-step, safe, and effective alternative to the conventional physical/ chemical methods. 1. Introduction Silver nanoparticles (AgNPs) have unique optical, thermal, and electrical properties. Over the last decade, silver nanoparticles have been known to have numerous applications in sensors [1–4], optics [5], energy [6,7], catalysis [8,9]; Zakaria et al., 2020), and the medical and phar- maceutical fields due to their high toxicity against microorganisms [10–12]. The ability of silver nanoparticles to disrupt the plasma mem- brane of pathogenic microorganisms and thus inhibit their activity has sparked a lot of interest in their use in health care [13]. AgNPs are non-toxic to eukaryotic cells but it exhibits high toxicity against pro- karyotic cells such as gram-positive bacteria, gram-negative bacteria, drug-resistant bacteria, viruses and fungi [14,15] and thereby it was the most commonly used broad-spectrum antimicrobial compound before the discovery of antibiotics in the early 20th century [16]. They have been used in different biomedical products such as contact lenses, bone cement, surgical masks, nano gels, nano lotions, wound dressing, etc. [17]. For many years, researchers have worked on the synthesis of AgNPs to investigate their antimicrobial properties. Recently, Lara et al. [16] and Swolana et al. [18] synthesized AgNPs which exhibited antifungal activity against Candida auris, a pathogenic fungus that is associated with blood serum infections and antibacterial effects against Staphylococcus epidermidis. The antibacterial effect of AgNPs inhibits cell division and DNA replication of the bacterial cells by releasing free silver ions from the nanoparticles which interact with the thiol groups of respiratory enzymes and the phosphorous-containing bases preventing cell division and DNA replication [19]. In this work, we aimed to study the antibacterial effect of the silver nanoparticles synthesized using P. Biglandulosa aqueous leaf extract (PbAgNPs) that acted as a reducing as well as a capping agent. Silver nanoparticles have been studied to be biocompatible as they could perform the desired function without causing any undesirable immunity response, allergic reactions, inflammatory and chronic * Corresponding author. E-mail address: nidhin.m@christuniversity.in (N. M). Contents lists available at ScienceDirect Current Research in Green and Sustainable Chemistry journal homepage: www.elsevier.com/journals/ current-research-in-green-and-sustainable-chemistry/2666-0865 https://doi.org/10.1016/j.crgsc.2021.100112 Received 10 April 2021; Received in revised form 15 May 2021; Accepted 15 May 2021 Available online 27 May 2021 2666-0865/© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/). Current Research in Green and Sustainable Chemistry 4 (2021) 100112