Biocatalysis and Agricultural Biotechnology 24 (2020) 101518 Available online 30 January 2020 1878-8181/© 2020 Elsevier Ltd. All rights reserved. Medicinal plants: Treasure trove for green synthesis of metallic nanoparticles and their biomedical applications Harish Chandra a, 1 , Pragati Kumari b, **, 1 , Elza Bontempi c , Saurabh Yadav d, * a Department of Botany and Microbiology, Gurukula Kangri Vishwavidayalaya, Haridwar, 249404, India b Scientist Hostel-S-02, Chauras Campus, Srinagar Garhwal, Uttarakhand, 246174, India c INSTM and Mechanical and Industrial Engineering Department, University of Brescia, Via Branze 38, 25123, Brescia, Italy d Department of Biotechnology, Hemvati Nandan Bahuguna Garhwal (Central) University, Srinagar Garhwal, Uttarakhand, 246174, India A R T I C L E INFO Keywords: Green synthesis Nanoparticle Nanotechnology Medicinal plants Antibacterial Antifungal ABSTRACT The cornerstone of nanoscience and nanotechnology are nanoparticles which have immense power and func- tional ability in diverse felds. Nanoparticles are synthesized by physical, chemical methos but limitations are due to its toxicity. We have discussed few green synthesis routes which are eco friendly and less toxic methods, including alage, microorganisms, plants etc.. Expoiting the potential of medicinal plants, is one of the green synthesis routes and is signifcant because the current therapeutic approaches have toxicity problems and mi- crobial multidrug resistance issues. As the metal nanoparticles have received great attention across the globe, so in this study we have discussed and focused many different metallic nanoparticles obtained by green synthesis using medicinal plants. We have also discussed the types, size and medicinal properties like antibacterial, antifungal, anticancer, antiviral activities of nanoparticles. The biomolecules, secondary metabolites and co- enzymes present in the plants help in easy reduction of metal ions to nanoparticles. Such nanoparticles are considered as potential antioxidants and promising candidates in cancer treatment. The simplifed model sum- marises the green synthesis, its characterization using physicochemical means and their biomedical applications. Succinctly, we have discussed the recent advances in green synthesis of metallic nanoparticles, milestones, therapeutic applications and future perspectives of biosynthesized nanoparticles from some important medicinal plants. 1. Introduction The life expectancy of human beings has increased after the immense progress in medical sciences. Earlier the average life of a human being was about 50–60 years. Now it has been increased to approx 70 years and above (Roser 2016). This is possible due to immense contribution of applied research in medical sciences in the feld of diagnostics, pre- vention and targeted treatment (Roser 2016). The most valuable contribution of microbiological sciences was the discovery of antibi- otics. When frst antibiotic penicillin was discovered and introduced in 1940, it saved the life of many soldiers who earlier died of septic or wound infection mainly caused by Staphylococcus spp (Tan and Tatsu- mura, 2015). Soon after the introduction of penicillin, Staphylococcus became resistant and use of penicillin became less relevant to treat Staphylococcus infection.. During evolution, bacteria developed resis- tance towards antimicrobial agents (Fair and Tor, 2014). Also the indiscriminate use of these antibiotics have added to the woes. Re- searchers across globe are quite aware that such irrational use of anti- biotics, will make the treatment diffcult as antibiotics will become toothless (Ventola, 2015). So the world is in the search of newer alter- native of pharmaceuticals which are small and capable of targeted de- livery (Taylor, 2013). Thus, the scientists are keen to investigate smaller medicinally important molecules and nanotechnology seems to be the result of that curiosity. Nanotechnology is emerging science which deals with the study of small particles or nanoscale materials whose size ranges from 1-100 nm (1 nm ¼ 10 9 m). Ancient system of medicine in India, Ayurveda deals with the different formulations which are suggestive about the nanosize * Corresponding author. ** Corresponding author. E-mail address: saurabhyadav40@rediffmail.com (S. Yadav). 1 Contributed equally. Contents lists available at ScienceDirect Biocatalysis and Agricultural Biotechnology journal homepage: http://www.elsevier.com/locate/bab https://doi.org/10.1016/j.bcab.2020.101518 Received 4 September 2019; Received in revised form 6 January 2020; Accepted 28 January 2020