Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti Influence of shading treatment on yield, morphological traits and phenolic profile of sweet basil (Ocimum basilicum L.) Donato Castronuovo a,1 , Daniela Russo b,c,1 , Rossana Libonati b,d , Immacolata Faraone b,c , Vincenzo Candido a, ⁎ , Pietro Picuno a , Paula Andrade d , Patricia Valentao d , Luigi Milella b,c, ⁎⁎ a School of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Viale dell'Ateneo Lucano, 10, 85100, Potenza, Italy b Department of Science, University of Basilicata, Viale dell’Ateneo Lucano, 10, 85100, Potenza, Italy c Spinoff BioActiPlant S.R.L. Department of Science, University of Basilicata, Viale dell’Ateneo Lucano, 10, 85100, Potenza, Italy d REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, nº 228, 4050-313, Porto, Portugal ARTICLE INFO Keywords: Abiotic stress factors Shading strategies Plastic nets Lamiaceae Plant growth Antioxidant activity ABSTRACT We investigated the roles of different shading strategies on plant growth, antioxidant activity and phenolic profile of sweet basil (Ocimum basilicum L.), a widely used herb with culinary and medicinal properties. Sweet basil plants were cultivated in a commercial multi-span tunnel-greenhouse covered with an EVAC plastic film, shaded from solar radiation in five different ways: n. 1, by calcium hydroxide whitening; n. 2, installing up - or n. 3, under - the greenhouse roof, a PE-HD white reflective net with 36% shading factor; n. 4, installing up - or n. 5, under - the greenhouse roof, a PE-HD white reflective net with 58% shading factor. The remaining part of the greenhouse (n. 6 - control) was unshaded. In each trial, yield traits, antioxidant activity and contents of phe- nolics of sweet basil plants were assessed to evaluate the influence of the shading strategy on these parameters. The antioxidant capacity was evaluated by using three different in vitro assays: DPPH scavenging activity, re- ducing power (FRAP) and lipid peroxidation inhibition (BCB). To compare the data obtained by the different chemical methods, the relative antioxidant capacity index (RACI) was calculated. The yield was highest in unshaded plants. The control trial, in which the incoming solar radiation was filtered only by the film which covers the greenhouse, showed the highest RACI value (0.98), indicating that the antioxidant capacity was probably influenced by higher light and temperature conditions. Phenolic quantification, determined by HPLC- DAD, enabled to observe a correlation between the antioxidant power and the identified metabolites. 1. Introduction Sweet basil (Ocimum basilicum L.), a member of the Lamiaceae fa- mily, is a common herb native to India and cultivated all over the World. Traditionally, sweet (or common) basil is extensively used in food, as a spice and in economically important fields such as perfumery, pharmaceutical and medical industries, mostly for dental or oral care (Telci et al., 2006). These industries use both the volatile and non-vo- latile basil fractions, extracted mostly from the aerial parts (flowers and leaves). Because of their medicinal properties, basil essential oils are largely used in pharmaceutical industries. The leaves are perceived as antispasmodic, carminative and stomachic in ethnic medicine (Sajjadi, 2006) and are used to treat nausea, dysentery, gastroenteritis or ab- dominal cramps. Recent investigations have underlined the protective effects of basil against some xenobiotics, its capacity to stimulate the central nervous system and its radiation protective efficacy (Uma Devi et al., 2000). Essential oils extracted from sweet basil plants vary in productivity and quality, depending on the field conditions (Smitha and Vandana, 2016; Padalia et al., 2017). In terms of its chemical composition, O. basilicum contains a wide https://doi.org/10.1016/j.scienta.2019.04.077 Received 17 September 2018; Received in revised form 9 April 2019; Accepted 29 April 2019 Abbreviations: PE-HD, high-density poly ethylene; EVAC, ethylene-vinyl acetate; TPC, total polyphenol content; DPPH • , 2,2-diphenyl-1-picrylhydrazylradical; FRAP, ferric-reducing antioxidant power; TE, trolox equivalents; GAE, gallic acid equivalents; BCB, beta-carotene bleaching; AA, antioxidant activity; BHT, butyl hydroxy toluene; HPLC, high-performance liquid chromatography; DAD, diode array detection; LAI, leaf area index ⁎ Corresponding author at: School of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100, Potenza, Italy. ⁎⁎ Corresponding author at: Department of Science, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100, Potenza, Italy. E-mail addresses: vincenzo.candido@unibas.it (V. Candido), luigi.milella@unibas.it (L. Milella). 1 These authors contributed equally to this work. Scientia Horticulturae 254 (2019) 91–98 0304-4238/ © 2019 Elsevier B.V. All rights reserved. T