ISSN:
1573-5036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The active agents responsible for chelating Zn were isolated from aqueous extracts of vaccinium and barley leaves by sephadex gel and identified by TLC and UV and IR spectroscopy. Treatment of the aqueous extracts with ZnCl2 caused dissociation of the Zn-chelate on the column, and this was avoided by using ZnO. Drying the leaves at 40–50°C was found to affect the chemical composition and Zn chelating activity of aqueous extracts. In fresh leaves, the active compound was found to be ellagic acid and chelation seems to occur with both the lactone ring and with the orthosubstituted OH groups. The Zn chelating ligand in dried vaccinium leaf extract was found to be a catechin and chelation is more likely to occur with orthosubstituted OH. In water extracts of fresh barley leaves the phenolic compounds were not active whilst the amino acids valine, alanine, threonine, glutamic, asparagine, methionine, and a compound similar to norleucine in its chromatographic behaviour, possibly NH3, were active in chelating Zn. It seems that drying the leaves and subjecting them to microbial decomposition affect the phenolic compounds, catechin and amino acid contents of these plants. This seems to affect the active Zn-chelating ligand. The Zn-dissolving capacity of aqueous extract seems to be significantly affected by drying and grinding and by the type of plants and not affected by microbial decomposition. re]19720807
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00011405
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