J Agric Food Chem. 2008 Sep 24;56(18):8685-91. Epub 2008 Aug 20.
Effects of nitrogen fertilization on the phenolic composition and
antioxidant properties of basil (Ocimum basilicum L.).
Nguyen PM, Niemeyer ED.
Department of Chemistry and Biochemistry, Southwestern University, 1001
East University Avenue, Georgetown, Texas 78626, USA.
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 the culinary
herb, 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
PMID: 18712879 [PubMed - indexed for MEDLINE]
Fish emulsion every 2 weeks, huh? Uh-huh.
And then there is last years discussion about chitosan. Anyone try it?
Click to see the full signature.