Abstract
Abstract BACKGROUND Nitrogen availability is an important environmental factor that determines the production of phenolic compounds in vegetables, but the relationship between low nitrogen‐induced alterations of phenolic compounds in vegetable crops and the cellular antioxidant activities of these compounds remains unclear. This study investigated the effect of reduced nitrogen supply (0.05 mmol L −1 nitrate) on phenolic metabolism in lettuce and the protective role of phenolic extracts against H 2 O 2 ‐induced oxidative stress in Caco‐2 cells by determining cell damage, reactive oxygen species (ROS) content and antioxidant enzyme activities. RESULTS Reduced nitrogen supply significantly improved the accumulation of phenolic compounds in lettuce, which was partially correlated with the upregulation of genes related to the phenolic synthesis pathway. Phenolic extracts from lettuce cultivated in low‐nitrogen medium exhibited a better protective effect against H 2 O 2 ‐induced oxidative damage in Caco‐2 cells than those from lettuce cultivated with adequate nitrogen. These extracts act by increasing the activities of antioxidant enzymes and, subsequently, by inhibiting ROS overproduction, which leads to a decrease in mitochondrial membrane and DNA damage. The results of HPLC and correlation analyses implied that the improvement in the protective capacity of lettuce extracts after low‐nitrogen treatment may be related, not only to the increased content of phenolic compounds, but also to the increased percentage contribution of chlorogenic acid and quercetin derivatives to the total phenolic content. CONCLUSION Reduction in nitrogen supply can be a powerful strategy to modify phenolic metabolism and composition in lettuce and, consequently, to improve their antioxidant capacity. © 2019 Society of Chemical Industry
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Claims 5
Claim · model-written summary
Reduced nitrogen significantly increased phenolic accumulation in lettuce.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- Reduced nitrogen supplye0
- Outcome
- accumulation of phenolic compoundse0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Reduced nitrogen supply significantly improved the accumulation of phenolic compounds in lettuce”
Claim · model-written summary
Phenolic accumulation was partly correlated with higher expression of synthesis genes.
- Gene
- genes related to the phenolic synthesis pathwaye0
- Outcome
- upregulation of genes related to the phenolic synthesis pathwaye0
- Direction
- upregulatione0
Not reportedTaxon
Verbatim
e0“which was partially correlated with the upregulation of genes related to the phenolic synthesis pathway.”
Claim · model-written summary
Low nitrogen lettuce extracts better protected Caco 2 cells from oxidative damage.
- Taxon
- lettuceLactuca sativae0
- Treatment
- low‐nitrogen mediume0
- Outcome
- protective effect against H 2 O 2 ‐induced oxidative damage in Caco‐2 cellse0
- Direction
- bettere0
- Comparator
- adequate nitrogene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phenolic extracts from lettuce cultivated in low‐nitrogen medium exhibited a better protective effect against H 2 O 2 ‐induced oxidative damage in Caco‐2 cells than those from lettuce cultivated with adequate nitrogen.”
Claim · model-written summary
Low nitrogen extract protection involved increased antioxidant enzyme activities and reduced ROS.
- Outcome
- decrease in mitochondrial membrane and DNA damagee0
- Qualifier
- increasing the activities of antioxidant enzymese0
Not reportedTaxon
Verbatim
e0“These extracts act by increasing the activities of antioxidant enzymes and, subsequently, by inhibiting ROS overproduction, which leads to a decrease in mitochondrial membrane and DNA damage.”
Claim · model-written summary
Improved extract protection may relate to greater phenolic content and chlorogenic acid and quercetin derivative proportions.
- Taxon
- lettuceLactuca sativae0
- Compound
- chlorogenic acid and quercetin derivativese0
- Outcome
- improvement in the protective capacity of lettuce extractse0
- Direction
- improvemente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the improvement in the protective capacity of lettuce extracts after low‐nitrogen treatment may be related, not only to the increased content of phenolic compounds, but also to the increased percentage contribution of chlorogenic acid and quercetin derivatives to the total phenolic content.”
The same questions in other papers
nitrogen · quality: phytochemicals · Lactuca sativa (garden lettuce)Positive and negative results
5 papers in the same direction as this paper · 10 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- positive
- positive
12 papers more in this group
See all 16 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.