Effects of Nitrogen Fertilization on the Phenolic Composition and Antioxidant Properties of Basil (Ocimum basilicumL.)

Abstract

Many herbs and spices have been shown to contain high levels of polyphenolic compounds with potent antioxidant properties. In the present study, we explore how nutrient availability, specifically nitrogen fertilization, affects the production of polyphenolic compounds in three cultivars (Dark Opal, Genovese, and Sweet Thai) of one of the most common culinary herbs, basil (Ocimum basilicum L.). Nitrogen fertilization was found to have a significant effect on total phenolic levels in Dark Opal (p < 0.001) and Genovese (p < 0.001) basil with statistically higher phenolic contents observed when nutrient availability was limited at the lowest (0.1 mM) applied nitrogen treatment. Similarly, basil treated at the lowest nitrogen fertilization level generally contained significantly higher rosmarinic (p = 0.001) and caffeic (p = 0.001) acid concentrations than basil treated at other nitrogen levels. Nitrogen fertilization also affected antioxidant activity (p = 0.002) with basil treated at the highest applied nitrogen level, 5.0 mM, exhibiting lower antioxidant activity than all other nitrogen treatments. The anthocyanin content of Dark Opal basil was not affected by applied nitrogen level, but anthocyanin concentrations were significantly impacted by growing season (p = 0.001). Basil cultivar was also determined to have a statistically significant effect on total phenolic levels, rosmarinic and caffeic acid concentrations, and antioxidant activities.

Nitrogen Nutrition Effect on Aeroponic Basil (<i>Ocimum basilicum </i><spanstyle='mso-bidi-font-style:italic'>L.</span>) Catalase and Lipid Peroxidation

“…There are several methodological differences between the studies which explore the influence of N nutrition in basil plants, such as hydroponic (Kiferle et al, 2013) or field culture (Sifola and Barbieri, 2006), winter (Nurzynska-Wierdak et al, 2013), spring (Kiferle et al, 2013), summer or fall seeding (Nguyen and Niemeyer, 2008) and a wide range of N treatment concentrations from 0.1 mM (Nguyen and Niemeyer, 2008) to 0.9 g dm -3 of growing medium (NurzynskaWierdak et al, 2013) that is 64 mM. In spite of the above alterations, it is considered that in basil plants the increased N nutrition decreases both phenolics concentration and antioxidant activity (Nguyen and Niemeyer, 2008;Kiferle et al, 2013) while enhances the accumulation of essential oils (Sifola and Barbieri, 2006;Nurzynska-Wierdak et al, 2013) which also exhibit antioxidant activity (Amorati et al, 2013). These contradictious findings correspond to our results which indicate that aeroponically treated high N nutrition enhances both the enzymic antioxidative defense in leaves and roots and the leaf oxidative damages, implying that N nutrition induces oxidative stress while the plants develop adaptations of their enzymic and non-enzymic antioxidant defense.…”

“…It is also used for cosmetical and pharmaceutical preparations as it contains large amounts of essential oils (Sifola and Barbieri, 2006;Kiferle et al, 2013) and antioxidant polyphenolic compounds with anticancer, antibacterial, antifungal and anti-inflammatory capabilities (Nguyen and Niemeyer, 2008;Nurzynska-Wierdak et al, 2013). Basil is generally cultivated in open field (Kiferle et al, 2013), but it is also commercially produced in greenhouses (Nguyen and Niemeyer, 2008).…”

“…It is also used for cosmetical and pharmaceutical preparations as it contains large amounts of essential oils (Sifola and Barbieri, 2006;Kiferle et al, 2013) and antioxidant polyphenolic compounds with anticancer, antibacterial, antifungal and anti-inflammatory capabilities (Nguyen and Niemeyer, 2008;Nurzynska-Wierdak et al, 2013). Basil is generally cultivated in open field (Kiferle et al, 2013), but it is also commercially produced in greenhouses (Nguyen and Niemeyer, 2008). The major advantage of basil greenhouse hydroponic cultivation is the manipulation of growing conditions such as all-year round production, higher quality and ease of processing of harvested material on account of minimal contamination from pollutants, pests and pathogens (Nguyen and Niemeyer, 2008;Kiferle et al, 2013).…”

“…Basil is generally cultivated in open field (Kiferle et al, 2013), but it is also commercially produced in greenhouses (Nguyen and Niemeyer, 2008). The major advantage of basil greenhouse hydroponic cultivation is the manipulation of growing conditions such as all-year round production, higher quality and ease of processing of harvested material on account of minimal contamination from pollutants, pests and pathogens (Nguyen and Niemeyer, 2008;Kiferle et al, 2013).…”

Different availabilities of reduced nitrogen: response to oxidative stress in chicory plants

“…Polyphenols production in the plants depends on genetics and physiologicals factors, such as genotypes and maturation (Rapisarda and Giuffrida, 1992); on other factors such as UV (Kondo et al, 2002), osmotic stress (Javed and Ikram, 2008) and nutrients availability. Particularly, nitrogen source has a potential effect on polyphenols formation (Nguyen and Niemeyer, 2008). Since nitrogen supply is indispensable to increase plant productions, the evaluation of the influence of nitrogen reduced form in nutritive solution on molecules and ROS scavenging activities production, results very interesting.…”