NADP-dehydrogenases of medicinal plants.

Medicinal plants usually contain metabolites formed by secondary biosynthetic pathways for example phenylpropanoid and shikimate pathway, which depend on NAPDH availability. In this work total content of phenolic compounds and flavonoids was determined in 10 medicinal plants common for Czech Republic. Activity of enzymes providing NADPH was determined as well. These enzymes were glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), NADP-isocitrate dehydrogenase (NADP-ICDH, EC 1.1.1.42), NADP-malic enzyme (oxalacetate decarboxylating) (NADP-ME, EC 1.1.1.40). The activity of shikimate dehydrogenase (SDH, EC 1.1.1.25), the main enzyme of shikimate pathway, was also determined. Extraction methods were optimized for each assessment. Applicable source for NADP-dependent enzymes are black radish (Raphanus sativus L. var. niger), garlic (Allium sativum L.) and mint (Mentha piperita L). The highest content of phenolic compounds and flavonoids was determined in sage (Salvia officinalis), lemon balm (Melissa officinalis L.) and Mentha citrata. Extraction with methanol was more effective than extraction with hot water. More extraction methods and studies are necessary for characterization of individual compounds and principals on which they work. Key words: medicinal plants, NADP-dependent enzymes, phenolic..