Variety-based research on the phenolic content in the aerial parts of organically and conventionally grown buckwheat.

The aim of this study was to evaluate the impact of different farming types-organic and conventional-on phenolic content in buckwheat varieties grown in Lithuania. Rutin was identified as the dominant phenolic compound in contrast to both phenolic acids (chlorogenic and neochlorogenic acids) and other flavonoids (quercetin and quercitrin). It was determined that variety had the highest impact (p<0.05) on the phenolic content of various aerial parts of buckwheat. In most cases, farming practice significantly (p<0.05) affected the accumulation of phenolics in buckwheat. Organically grown plants usually contained higher amounts of phenolics than those grown under conventional farming conditions. According to a cluster analysis, varieties Panda, Zaleika, and VB Nojai were found to accumulate the highest amounts of phenolics.

Effect of farming systems on the yield, quality parameters and sensory properties of conventionally and organically grown potato (Solanum tuberosum L.) tubers.

The objectives of this two-year research were to study the impact of two different farming types, conventional and organic, on the yield and sensory properties of five Lithuanian varieties of potato tuber. The parameters and properties examined were: phenolic acids; dry matter and starch content; and the spread and intensity of Phytophthora infestans growth. It was determined that potato yield fluctuates with the variety, but for conventional farming it is significantly (p<0.05) higher than that obtained by organic farming. The farming type has no significant effect (p>0.05) on the content of phenolic acids. No significant effect (p>0.05) of farming type on dry matter and starch content, or sensory properties was found. No significant relation (p>0.05) was found between the content of phenolic acids and P. infestans spread. The spread of P. infestans was faster and infection was heavier in organically grown potatoes.

The effect of flavonoids on rat heart mitochondrial function.

In this study the effects of flavonoids (quercetin and its derivatives as rutin, hyperoside, quercitrin) on the oxidative phosphorylation in rat heart mitochondria were investigated. We found that all investigated flavonoids possessed uncoupling activity. Thus, quercetin, rutin, and quercitrin in dose-dependent manner induced a stimulation of the State 2 respiration rate by 10-110% with pyruvate + malate as substrate. The maximal stimulation of the State 2 respiration rate was obtained at 1.08 ng/ml of quercetin, 15.2 ng/ml of hyperoside and 44.4 ng/ml of rutin. Quercitrin had clearly lower effects. The State 3 respiration rate was also affected by flavonoids. Quercetin (from 1.08 ng/ml), hyperoside (from 10 ng/ml) and rutin (from 60 ng/ml) caused the decrease in State 3 respiration rate by 16-51%. We assume, that partial mitochondrial uncoupling (without affecting the State 3 respiration rate) induced by flavonoids could have a cardioprotective effect, and that mitochondria could be involved in the mechanism of this process.

Capillary electrophoretic analysis of flavonoids in single-styled hawthorn (Crataegus monogyna Jacq.) ethanolic extracts.

Flavonoids are an important group of natural compounds, which can prevent coronary heart disease and have antioxidant properties. Hawthorn is a well known and widely used medicinal plant due to its cardiotonic activity. Previous studies refer mostly to the HPLC analysis of the flavonoids: vitexin, quercetin, hyperoside, oligomeric procyanidins, which appear to be primarily responsible for the cardiac action of the plant. Aqueous ethanolic extracts of single-styled hawthorn (Crataegus monogyna Jacq., f.: Rosaceae Juss.) leaves and sprouts were analyzed by means of capillary zone electrophoresis (CZE). Influence of vegetation period on the extract qualitative composition and flavonoids quantities was evaluated. Sample preparation by extraction using different concentration of aqueous ethanol (40-96%, v/v) and the influence of extractant composition on the recovery of flavonoids are discussed in detail. The results obtained using CZE are compared to the results of spectrophotometric and HPLC analysis of the extracts. The effect of storage conditions of extracts (solar irradiation, temperature and duration) on degradation of flavonoids was investigated.