Labdane diterpenes from Stachys plumosa.

Three new labdane diterpenoids were isolated from the aerial parts of Stachys plumosa. The first two (1, 2) were the dextrorotatory enantiomers of the known 6-deoxyandalusol and 13-epijabugodiol. Structures were determined using NMR and MS techniques. The absolute stereochemistry of the third compound (3) was not experimentally proved.

Minor diterpenoids from Scutellaria polyodon.

Four minor neoclerodane diterpene constituents were isolated from the aerial parts of Scutellaria polyodon. These compounds were characterized as the new scupolins J (1) and K (2) and the previously known scutalpin O (3) and scutalsin.

Flavonol glycosides from Dryas octopetala.

Six flavonol glycosides and ent-epicatechin were isolated from Dryas octopetala and their structures elucidated by chemical and spectroscopic methods. Two new flavonoids, 3-O-alpha-L-arabinofuranosyl-8-methoxyquercetin (2) and 3-O-beta-galactopyranosyl-8-methoxykaempferol (6), were identified along with 3-O-beta-D-galactopyranosylquercetin (hyperin) (3), 3-O-alpha-L-arabinofuranosylquercetin (avicularin) (5), 3-O-beta-L-arabinopyranosylquercetin (4), and 3-O-beta-D-galactopyranosyl-8-methoxyquercetin (1).

Effect of benzyladenine on some enzymes of mitochondria and microbodies in excised sunflower cotyledons.

Benzyladenine (BA) increases the rate of expansion of dark-grown sunflower (Helianthus annuus L.) cotyledons. The hormone slightly enhances the development of the two glyoxysomal enzymes, isocitrate lyase and malate synthetase, during the first 3 days of germination and greatly accelerates their decay in the 2 following days. The levels of the peroxisomal enzymes, glycolate oxidase and glyoxylate reductase, are enhanced by BA more than those of the two glyoxysomal enzymes. These effects of BA on microbody enzymes are very similar to those of white light. Mitochondrial enzyme activities are increased to a varying extent by BA: the increase is minimal for fumarase, and maximal for cytochrome oxidase. The level of cytochrome oxidase is enhanced 346% at the 5th day of germination. Also, the rate of O(2) consumption is increased by BA, but the time course of this increased O(2) consumption does not match with that of cytochrome oxidase. Fusicoccin, a fungal toxin, mimics the effect of BA on cotyledon expansion, but fails to duplicate its action on microbody enzymes. This suggests that the effect of BA on microbody enzymes is not closely linked with the mechanism of growth promotion.

Citrate synthetase in mitochondria and glyoxysomes of maize scutellum.

Mitochondria and glyoxysomes were isolated from scutella of maize (Zea mays L.) by density gradient centrifugation. Citrate synthetase was partly solubilized from the organelles by sonication. The sonicated organelle suspensions were centrifuged at high speed, and the supernatants were used as enzyme preparations without further purification. The enzymes of the two organelles differ in all properties examined (pH activity curve, Km for substrates, elution volume on Sephadex G-100, mobility on starch gel at pH 7). Both enzymes are inhibited by ATP, but the inhibition is stronger for the mitochondrial enzyme. The inhibition is competitive for the mitochondrial enzyme and noncompetitive for the glyoxysomal enzyme. The glyoxysomal, but not the mitochondrial enzyme, is inhibited 40% with 1 mm ADP and cytidine triphosphate.