Fatty Acids, Essential Oil, And Phenolics Modifications of Black Cumin Fruit under NaCl Stress Conditions

Abstract

This research evaluated the effect of saline conditions on fruit yield, fatty acids, and essential oils compositions and phenolics content of black cumin (Nigella sativa). This plant is one of the most commonly found aromatics in the Mediterranean kitchen. Increasing NaCl levels to 60 mM decreased significantly the fruits yield by 58% and the total fatty acids amount by 35%. Fatty acids composition analysis indicated that linoleic acid was the major fatty acid (58.09%) followed by oleic (19.21%) and palmitic (14.77%) acids. Salinity enhanced the linoleic acid percentage but did not affect the unsaturation degree of the fatty acids pool and thus the oil quality. The essential oil yield was 0.39% based on the dry weight and increased to 0.53, 0.56, and 0.72% at 20, 40, and 60 mM NaCl. Salinity results on the modification of the essential oil chemotype from p-cymene in controls to γ-terpinene/p-cymene in salt-stressed plants. The amounts of total phenolics were lower in the treated plants. Salinity decreased mainly the amount of the major class, benzoics acids, by 24, 29, and 44% at 20, 40, and 60 mM NaCl. The results suggest that salt treatment may regulate bioactive compounds production in black cumin fruits, influencing their nutritional and industrial values.

The effects of salt and drought stress on phenolic accumulation in greenhouse-grown Hypericum pruinatum

“…Total phenolic contents of 5-and 7-day old plantlets treated with 10 and 50 μM of NaCl were significantly decreased in radish sprouts (Yuan et al, 2010). Similarly, total phenolic content decreased by 30, 54, and 61% in response to 20, 40, and 60 μM NaCl treatments in Nigella sativa (Bourgou et al, 2010). The differential accumulation of phenolic fractions under different salt treatments in the plant species with different salinity resistance suggests that salt resistant species and varieties may employ phenolic compounds, especially phenolic acids and flavonoids differentially to adapt to contrasting salinities (Mahmoudi et al, 2010).…”

“…Nonenzymatic components of the antioxidant defense system consist of various secondary metabolites, such as hydrophilic phenolics and flavonols, organic acids, lipophilic carotenoids, and watersoluble ascorbate and the enhancement of the phenolics metabolism is considered one of the responses to abiotic stresses (Close and McArthur, 2002). Phenolics are well-known antioxidant compounds having powerful radical scavenging ability and the distinct increase in phenolic content of plant tissues under salinity is thought to be involved in the prevention of stress-induced oxidative damage (Bourgou et al, 2010). It has been shown that salt stress induced disturbances in the secondary metabolic pathways, leading to an increase in phenolic compounds (Ksouri et al, 2007).…”

How Salt Stress Represses the Biosynthesis of Marrubiin and Disturbs the Antioxidant Activity of Marrubium Vulgare L

“…In brief, 1 mL of dissolved extract with different concentrations was mixed with 2.5 mL phosphate buffer (0.2 M, pH = 6.6), and 2.5 mL of a 10 g•L -1 potassium hexacyanoferrate [K 3 Fe(CN) 6 ] solution. After 30 min at 50º, 2.5 mL of a 100 g•L-1 aqueous trichloroacetic acid (TCA) solution was added and the mixture was stirred with a glass rod.…”

“…Most of these properties are attributed to their particular phenolic profile and to the furanoid labdane diterpene lactone marrubiin [16]. However, as for other secondary metabolites, the contents of these valuable compounds are likely influenced by abiotic stress [6]. Indeed, salinity can play the role of elicitor for biomolecular production, including polyphenols.…”

“…Plant responses to salinity have been extensively studied, and in most cases they were focused on general responses such as growth, photosynthesis, plant nutrition, and some biochemical and molecular parameters [3,5]. However, little attention has been paid to the effects of salinity on some non-enzymatic antioxidants, namely polyphenols that can play a pivotal role in the mechanism of tolerance/sensitivity of some plant species (particularly medicinal plant species) due to their well-recognized antioxidant activity [6]. The accumulation of phenolics in plant tissues is a distinctive characteristic of plant stress and their induction under different abiotic stress is well documented [7].…”