Hiroyuki Tazaki

Potato tuber-inducing activities of jasmonic acid and related compounds

Salicylic acid (SA) induced potato tuberization in vitro at concentrations greater than 10−5 M. A comparison of the tuber-inducing activities of various related compounds suggested that derivatives of benzoic acid with a free carboxyl group and a substituent at the C-2 position of the benzene ring have this activity. Although SA had the strongest activity among the compounds tested, the activity was about one thousandth of that of natural jasmonic acid (1R,2S-jasmonic acid) in terms of the threshold concentration for activity. Spraying SA to leaves of plants grown under tuber-noninducing conditions (long days) induced tuberization. However, the natural occurrence of SA was not detected in the leaves of potato plants that had been grown under tuber-inducing conditions (short days) and had begun to form tubers. The results seem to exclude the possibility of the involvement of SA in the natural tuberization of potato plants.

The anthocyanin responsible for purplish blue flower colour of Aconitum chinense

The anthocyanin in the purplish blue flowers of Aconitum chinense was identified as delphinidin 3-rutinoside-7-O-(6-O-(4-(6-O-(4-hydroxybenzoyl)-beta-D-glucosyl)oxyb enzoyl- beta-D-glucoside), violdelphin by means of chromatography, FAB-MS including MS-MS, 1H and 13C NMR. The anthocyanin is stable in neutral or slightly acidic aqueous solution and the absorption spectra in the pH range of 4.0-6.2 exhibited three characteristic bands at 534, 569 and 620 nm, which are practically identical with those of purplish blue petals of A. chinense. Thus the purplish blue flower colour is manifested by intramolecular co-pigmentation of the anthocyanin.

A FURANODITERPENOID FROM THE LIVERWORT JAMESONIELLA AUTUMNALIS

A new furanoditerpenoid, jamesoniellide C, has been isolated from the liverwort Jamesoniella autumnalis. The structure of jamesoniellide C was established by spectroscopic methods, including X-ray analysis which also established its relative stereochemistry.

Buchaninoside, a steroidal glycoside from Elaeodendron buchananii

Abstract A novel steroidal glycoside was isolated from the fruit of a tropical tree, Elaeodendron buchananii , as an antifeedant substance for Spodoptera exempta . The structure of the compound was determined to be a glycoside of 2α,3β-14-trihydroxy-16α-acetoxy-14β-carda-4,20 (22)-dienolide-7β,8β-epoxide.