Industrial Crops and Products 96 (2017) 91–101 Contents lists available at ScienceDirect Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop Evaluation of the effects of Zinc on the chemical composition and biological activity of basil essential oil by using Raman spectroscopy Muhammad Asif Hanif a , Haq Nawaz a,∗ , Muhammad Adnan Ayub a , Nayla Tabassum a , Nazish Kanwal a , Nosheen Rashid b , Muhammad Saleem c , Mushtaq Ahmad c a Department of Chemistry, University of Agriculture, Faisalabad, Pakistan b Faisalabad Institute of Research Science and Technology (FIRST), 250 R.B. Bardaykay, University Park Abbaspur, Faisalabad, Pakistan c National Institute of Lasers and Optronics (NILOP), Islamabad, Pakistan a r t i c l e i n f o Article history: Received 9 July 2016 Received in revised form 26 October 2016 Accepted 29 October 2016 Keywords: Basil Essential oil Zn based fertilizer Biological activity Raman spectroscopy a b s t r a c t The present study is performed to evaluate the effect of different concentrations of Zn as fertilizer on the chemical composition of basil (Ocimum basilicum) essential oil and its biological activity including antiox- idant and antifungal activities. For this purpose, Raman spectroscopy along with GC–MS and antifungal assays are employed. Moreover, the effect of Zn is also determined on the vegetative growth and essen- tial oil yield. The treatment with 0.09 mg/L of Zn showed maximum vegetative growth (0.24 ± 0.02 kg plant weight and 0.31 ± 0.03 m plant height) while the treatment with 0.15 mg/L of Zn revealed highest essential oil yield (0.48 ± 0.019%) as compared to 0.28 ± 0.005% for control. All essential oils exhibited significant total phenolic contents, total flavonol contents, antioxidant activity measured by hydrogen peroxide scavenging, inhibition of linoleic acid oxidation and DPPH free radical scavenging and Ferric reducing antioxidant power assay Antifungal activity of essential oils was performed by disc diffu- sion assay against Aspergillus niger and Penicillium notatum strains. The results of antifungal activity showed that essential oils isolated after treatment of 0.095 mg/L concentration of Zn fertilizer exhibited maximum antifungal activity. Chemical compositions of isolated essential oils were determined by Gas Chromatography-Mass spectrometry (GC–MS) and Raman spectroscopy. The results of the GC–MS and Raman spectroscopy have revealed that the linalool is found to be as a major chemical compound in Ocimum basilicum essential oil. Moreover, Raman spectroscopy has identified the effect of the Zn on the concentration of the biological components present in essential oil showing that highest concentration of linalool found in the essential oil obtained from the basil plants which were given 0.095 mg/L of Zn fertilizer treatment that might be responsible for the maximum biological activities of this essential oil. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Sustainable production of agriculture is an ever increasing con- cern for farmers. There are many factors that affect vegetative growth, active substances, quality and yield of essential oil in aro- matic medicinal plants. Among these several factors, availability of the nutrients is the most significant controllable factor that plays an important role in the biosynthesis, quality and yield of secondary metabolites including essential oil (Chand et al., 2015; Pal et al., 2016). Yield and chemical constituents of essential oil depend on the type of nutrients available to plants (Sakr et al., 2012; Sharafzadeh et al., 2011). Therefore, fertilizer with exact con- ∗ Corresponding author. E-mail address: haqchemist@yahoo.com (H. Nawaz). centrations of micro and macronutrients are extremely important for high yield and better quality of essential oil. Micronutrients such as Mn, Cu, Zn and Fe control various physiological activities of the crop by intruding the level of chlorophyll content in leaves which ultimately influence the photosynthetic activity of the plants and biosynthesis of essential oil (Yadegari, 2014). Previously, it has been reported that application of the chemical fertilizers changed the major chemical constituents of essential oil isolated from Sat- ureja and Thymus vulgaris (Alizadeh et al., 2010; Baranauskiene et al., 2003). Zinc (Zn) is an essential micronutrient for normal crop growth. It is involved in antioxidant enzymes, carbon assimilation, free radical removal, saccharide accumulation and utilization of carbon in terpenes biosynthesis (Rezaeieh et al., 2016). Its defi- ciency can severely decrease plant growth and essential oil yield (Ali et al., 2008). Essential oil is secondary metabolite of plant, composed of terpenes and its oxygenated derivatives terpenoids, http://dx.doi.org/10.1016/j.indcrop.2016.10.058 0926-6690/© 2016 Elsevier B.V. All rights reserved.