ENVIRONMENTAL BIOTECHNOLOGY Multifunctional theranostic applications of biocompatible green-synthesized colloidal nanoparticles Muhammad Ovais 1,2,3 & Ali Talha Khalil 1,4 & Abida Raza 2 & Nazar Ul Islam 5 & Muhammad Ayaz 6 & Muthupandian Saravanan 7 & Muhammad Ali 1 & Irshad Ahmad 8 & Muhammad Shahid 5 & Zabta Khan Shinwari 1,4,9 Received: 4 December 2017 /Revised: 7 March 2018 /Accepted: 10 March 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Phytochemicals offer immense promise for sustainable development and production of nanotechnology-enabled products. In the present study, Olax nana Wall. ex Benth. (family: Olacaceae) aqueous extract was used as an effective stabilizing agent to produce biogenic silver (ON-AgNPs) and gold nanoparticles (ON-AuNPs), which were investigated for biocompatibility and prospective biomedical applications (antibacterial, anticancer, antileishmanial, enzyme inhibition, antinociceptive, and anti- inflammatory activities). Various characterization techniques (XRD, FTIR, SEM, TEM, DLS, EDX, and SAED) revealed efficient biosynthesis of ON-AgNPs (26 nm) and ON-AuNPs (47 nm). In the toxicological assessment, ON-AgNPs and ON- AuNPs were found biocompatible towards human RBCs and macrophages (IC 50 > 200 μg/mL). In a concentration range of 62.5–2000 μg/mL, a strong antibacterial effect was produced by ON-AgNPs against Staphylococcus epidermidis (MIC = 7.14 μg/mL) and Escherichia coli (8.25 μg/mL), while ON-AuNPs was only active against Staphylococcus aureus (9.14 μg/ mL). At a concentration of 3.9–500 μg/mL, a dose-dependant inhibition of HepG2 cancer cells was produced by ON-AgNPs (IC 50 = 14.93 μg/mL) and ON-AuNPs (2.97 μg/mL). Both ON-AgNPs and ON-AuNPs were found active against Leishmania tropica (KMH23) promastigotes (IC 50 = 12.56 and 21.52 μg/mL) and amastigotes (17.44 and 42.20 μg/mL), respectively, after exposure to a concentration range of 1–200 μg/mL for 72 h. Preferential enzyme inhibition against urease and carbonic anhydrase II were noted for ON-AgNPs (39.23 and 8.89%) and ON-AuNPs (31.34 and 6.34%), respectively; however, these were found inactive against xanthine oxidase at 0.2 mg/mL. In the in vivo antinociceptive (acetic acid-induced abdominal constrictions) and anti-inflammatory (carrageenan-induced paw edema) activities, ON-AgNPs and ON-AuNPs at doses of 40 and 80 mg/kg, significantly attenuated the tonic nociception (P < 0.001) and ameliorated the carrageenan-induced inflammation (P < 0.01, P <0.001). The results of in vitro and in vivo activities indicated that the biogenic nanoparticles can be used as valuable theranostic agents for further exploration of diverse biomedical applications. Keywords Phyto-nanotechnology . Green synthesis of nanoparticles . Green nanotechnology . Biological potential of nanoparticles . Nanoparticle drug delivery . Biocompatible nanoparticles * Nazar Ul Islam islanaz@yahoo.com 1 Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan 2 Pakistan Atomic Energy Commission, National Institute for Lasers and Optronics (NILOP), Islamabad 44000, Pakistan 3 Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China 4 Department of Eastern Medicine and Surgery, Qarshi University, Lahore 54000, Pakistan 5 Department of Pharmacy, Sarhad University of Science and Information Technology, Peshawar 25000, Pakistan 6 Department of Pharmacy, University of Malakand, Chakdara, Khyber Pakhtunkhwa 18800, Pakistan 7 Department of Medical Microbiology and Immunology, Institute of Biomedical Sciences, College of Health Sciences, Mekelle University, Mekelle, Ethiopia 8 Department of Life Sciences, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia 9 Pakistan Academy of Sciences, Islamabad 44000, Pakistan Applied Microbiology and Biotechnology https://doi.org/10.1007/s00253-018-8928-2