Tag Archives: quercetin

xxx L. Jankevica, O. Polis, A. Korica, I. Samsone, V. Laugale and M. Daugavietis
Environmental risk assessment studies on new plant protection products which have been elaborated from coniferous tree bark
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Environmental risk assessment studies on new plant protection products which have been elaborated from coniferous tree bark

L. Jankevica¹*, O. Polis², A. Korica², I. Samsone¹, V. Laugale³ and M. Daugavietis²

¹University of Latvia, Institute of Biology, Department of Experimental Entomology and Microbiology, Miera street 3, LV-2169 Salaspils, Latvia
²Latvian State Forest Research Institute 'Silava', Rīgas street 111, LV-2169 Salaspils, Latvia
³Latvia University of Life Sciences and Technologies, Institute of Horticulture, Graudu street 1, Ceriņi, Dobele District, LV- 3701, Latvia
*Correspondence: liga.jankevica@lu.lv

Abstract:

Nowadays there are still various chemical pesticides being applied in the course of ensuring plant protection. Since 2010, we have been working on the development of new, environmentally-friendly plant protection products which will provide an effective tool against pathogenic fungi and bacteria which cause disease in crop plants. The specific aim of this study was to evaluate a risk assessment for new plant protection products that have been elaborated on the basis of coniferous tree bark. Various products were tested which are extracted during the processing of wood bark from pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.). Ethanol extracts were formulated and applied during these experiments. Two formulations, which showed anti-fungal activity in vitro and in field trials on fruit crops (involving strawberries and raspberries) were selected for the risk assessment studies. The impact was studied of formulation treatment on crop plants and soil biological activity, and the accumulation of residues of active substances in crop plants and soil. The application of new formulations did not show any negative effect on the chlorophyll content and the chlorophyll fluorescence of plant leaves. The results showed that pine and spruce bark extract formulations contain active compounds (coumaric acid, quercetin, epicatechin, and ferulic acid) within the range of 5.1–5.9 mg kg-1 and 11.1–443.9 mg kg-1 respectively. The amount of active substances which were determined in most cases was higher in the spruce bark extract formulation when compared to the pine bark extract formulation. Our results confirmed the presence of active compounds – epicatechin, quercetin, and coumaric acid – in strawberry fruits which remained untreated and in those that were treated with spruce ethanol extract formulation. Untreated raspberry fruits contained all four active substances within the range of 81–5,300 μg kg-1. We observed a significant increase of coumaric acid and quercetin in raspberries after their having been treated with spruce bark extract formulation in a 2% concentration, P < 0.05, and did not find any negative impact for spruce bark extract formulations when used on soil microbial biomass.

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1419–1426 A.C. Olcay, G. Bilir, Ö. Taş, M. Deniz and D. Ekinci
Partial Purification of β–glucosidase enzyme from soybean (Glycine max) and determination of inhibitory effects two quercetin derivatives on enzyme activity
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Partial Purification of β–glucosidase enzyme from soybean (Glycine max) and determination of inhibitory effects two quercetin derivatives on enzyme activity

A.C. Olcay, G. Bilir, Ö. Taş, M. Deniz and D. Ekinci*

Ondokuz Mayıs University, Faculty of Agriculture, Department of Agricultural Biotechnology, TR 55139 Samsun, Turkey; e-mail: deniz.ekinci@omu.edu.tr

Abstract:

 Glucosidases are enzymes that catalyze the hydrolysis of the glycosidic linkage of glycosides, leading to the formation of a sugar hemiacetal or hemiketal and the corresponding free aglycon. Activity of glucosidases is crucial for several biochemical processes. Thus, discovery of new glucosidase inhibitors is crucially important owing to potential therapeutic applications of this enzyme in the treatment of diabetes, human immunodeficiency virus infection, metastatic cancer, lysosomal storage disease etc. In the current study, inhibitory potential of ‘quercetin’ and its isomeric form ’morin hydrate’ on the activity of β-glucosidase enzyme, present in the extract of soybean (Glycine max L.) seeds, were investigated. The compounds exhibited moderate inhibitory action in low milimolar concentrations. I50 values were calculated as 0.188 and 0.138 mM for quercetin and morin hydrate, respectively. The results have confirmed that these compounds can be used as leads for designations of novel glucosidase inhibitors which would be used in medicinal biotechnology and food science and technology.

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