Raphanusol A,a new growth inhibitor from sakurajima radish seedlings

A new growth inhibitor, raphanusol A, isolated from an acetone extract of light-exposed seedlings of Sakurajima radish, was characterized as 1-,β,4-di-O-(4-hydroxy-3,5-dimethoxycinnamoyl) gentiobiose by chemical methods and spectral data.     

Biosynthesis of 3-methoxycarbonylpropylglucosinolate in an Erysimum species

Incorporation of DL-2-aminohexanedioic acid, DL-2-amino-5-methoxycarbonyl-pentanoic acid and DL-methionine into 3-methoxycarbonylpropylglucosinolate have been demonstrated using an Erystmum species. The data support the following sequence of biosynthetic reactions: 2-aminohexanedioic acid is methylated by methionine; the resulting 2-amino-5-methoxycarbonyl-pentanoic acid is then converted into the glucosinolate. 2-Amino-5-methoxycarbonyl-pentanoic acid has been tentatively identified as a natural product in the plant.     

A taxonomic revision of Crambe, sect. Leptocrambe (Brassicaceae)

As part of a revision of the genus Crambe based on the morphological study of herbaria and cultivated material, the systematics of sect. Leptocrombe DC. is presented here. Section Leptocrambe is considered to comprise five species: C. kilimandscharica O. E. Schulz, C. sinuatodentata Hochst. ex Petri, C. hispanica L., C. filiformis Jacq. and C. kralikii Coss. C. hispanica includes three subspecies, subsp. hispanica , subsp. glabrata (DC.) Cout. and subsp. abyssnica (Hochst. ex R. E. Fr.) stat. nov. which includes var. dyssinica and var. meyeri (O. E. Schulz) comb. nov. C. kralikii includes two subspecies, subsp. kralikii and subsp. garamas (Maire) Podlech.     

Interactions of thioglucoside glucohydrolase and epithiospecifier protein of cruciferous plants to form 1-cyanoepithioalkanes

Allylglucosinolate is converted to 1-cyano-2,3-epithiopropane by interaction of the thioglucoside glucohydrolase and epithiospecifier protein from several genera: Brassica, Crambe, Armoracia and Sinapis. The interactions occur across genetic lines, indicating non-specific requirements for epithiospecifier protein and thioglucoside glucohydrolase.     

Tarsal contact chemoreceptor response to glucosinolates and cardenolides mediating oviposition in Pieris rape

Abstract. Water-soluble extracts of a host crucifer (Brassica oleracea L.) and non-host crucifer (Erysimum cheiranthoides L.) and isolated pure cardenolides and glucosinolates were tested on Pieris rapae L. (Lepidoptera: Pieridae) butterflies in oviposition assays and by electrophysiological recordings from the contact-chemoreceptor sensilla of the prothoracic tarsi. Ten different glucosinolates stimulated oviposition to varying degree when put on non-host plant leaves. The most active compounds were glucobrassiein and gluconasturtiin (methylindole and phenylethyl aglycone), whereas glucocapparin, sinalbin. glucotropaeolin, sinigrin and glucoalyssinin had intermediate activity. Glucocheirolin, glucoerucin and glucoiberin (sulphur-containing aglycone) were significantly less active. Of eight cardenolides applied to host-plant leaves (100 μg each), four glycosides deterred oviposition strongly (erysimoside, erychroside, cymarin and K-strophanthin-β). Erycordin, helveticoside, digitoxin and strophanthidin had little or no deterrent activity. Sensilla located laterally on the prothoracic tarsi of female butterflies contained one receptor cell sensitive to sucrose. None of the tested extracts or pure compounds stimulated any cell in these sensilla. In contrast, the cells in the medial sensilla showed little or no sensitivity to sucrose. One cell was found to be sensitive to cardenolide glycosides. The threshold for one of the most active compounds, erychroside, was about 0.1 μg/ml (1.5 times 10^-7 M). Two receptor cells, characterized by spikes of differing amplitude, were sensitive to glucosinolates. One of these, with larger amplitude spikes, seemed to be the same as the cell sensitive to cardenolides. The threshold for the most active glucosinolates, glucobrassicin and gluconasturtiin was estimated to be below 0.1 mg/ml (2 times 10^-4 M). The neural activity of both classes of compounds, cardenolides and glucosinolates, was significantly correlated with their behavioural activity as deterrents or stimulants.     

A review of the genus Graellsia BoisS. including Draba L.section Helicodraba Schultz (Brassicaceae)

A collection from the High Atlas of Morocco drew attention to similarities between Draba hederifolia Coss., a Moroccan endemic, and Graellsia a genus from S. W. Asia. The morphology, leaf flavonoids, trichomes, chromosomes and distribution of these plants are discussed and a new systematic account of Graellsia incorporating Draba hederifolia is given.