Akiko Matsumoto

A multichemical defense mechanism of bitter oliveOlea europaea (oleaceae)

Olea europaea (Oleaceae) is resistant in nature to insect and microbe attack. Two types of chemical protection were found in the foliage. One type is the bitterseco-iridoid glycosides oleuropein (1) and ligstroside (2); The other is a physical barrier of crystalline oleanolic acid (4) that coats the leaf surface. Theseco-iridoid glycosides were isolated using two different countercurrent chromatographies: rotation locular countercurrent chromatography (RLCC) and droplet countercurrent chromatography (DCCC). The dimethyl ester (III) was shown to be an artifact. This is the first isolation of ligstroside fromO. europaea. In an antimicrobial test by the paper disk method againstBacillus subtilis, Saccharomyces cerevisiae, andEscherichia coli, compounds I, II, and III inhibited a growth ofB. subtilis at pH 7. Similar tests under the influence of β-glucosidase suggest an aglycone of oleuropein, either the hemiacetal (i) or the possible enal-aldehyde (ii), could be the active intermediate. This intermediate could be produced rapidly in response to microorganism invasion. Oleuropein producing such a postinfection active intermediate could be referred to as a phytoalexin precursor.

New insect ecdysis inhibitory limonoid deacetylazadirachtinol isolated from azadirachta indica (meliaceae) oil

Abstract Insect bioassay-guided fractionation of neem oil expressed from the fresh fruits of Azadirachta indica (Meliaceae) resulted in the isolation and structural elucidation of a new limonoid, deacetylazadirachtinol ( 1 ). In addition, four previously elucidated limonoids, including azadirachtin ( 2 ), salannin( 3 ), 6- 0 -acetylnimbandiol ( 4 ), and 3-desacetylsalannin ( 5 ), were isolated from the same source, spectrally identified, and bioassayed. The structure of 1 was elucidated by spectral comparison with the known azadirachtin using their 1H-1H and 1H-13C 2D NMR spectra to assign the total 1H and 13C chemical shifts. Deacetylazadirachtinol was found to be as potent as azadirachtin in the inhibition of insect ecdysis when fed in artificial diet to larvae of the tobacco budworm. Heliothis virescens (Noctuidae). The other isolated limonoids were much less active against H. virescens .

Structure of deacetylazadirachtinol application of 2D1H-1H and 1H-13C shift correlation spectroscopy

Abstract A new insect antifeedant, and ecdysis inhibitor deacetylazadirachtinol, was isolated from Azadirachta indica (Meliaceae) collected in Haiti and its structure (1) was elucidated by the spectral comparison with azadirachtin using two-dimensional 1H-1H and 1H-13C shift correlation spectroscopies.

Efficient isolation of ecdysteroids from the silkworm, Bombyx mori by droplet counter-current chromatography

The insect moulting hormones, 20-hydroxyecdysone, and its precursor, ecdysone were first isolated from the pupae of silkworm Bombyx mori using a classical solid support chromatographic technique. We have developed a simple procedure for isolation of 20-hydroxyecdysone and ecdysone from B. mori by droplet counter-current chromatography (DCCC). DCCC method was very efficient for isolation of such a small amount as insect hormones.

Antitumor Promoters from Plants Used as Condiments or Garnishes

As part of a screening program for cancer chemopreventive agents of plant origin, we have examined the antitumor-promoting activity of extracts and constituents of edible or medicinal plants. Primary screening for antitumor promoters was carried out using an in vitro short-term assay. Inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation were observed in this assay. The isolated active components were further tested using in vivo antitumor-promoting assays against mouse skin and lung. A variety of phytochemicals such as sesquiterpenes, biflavones, lipids, lignans, and other phenolic compounds were isolated as active principles by monitoring their inhibitory effects on EBV-EA activation. Among these, drimane-type sesquiterpenes and acetylenic compounds showed potent antitumor-promoting activities in vivo. They were derived from edible plants used as condiments or garnishes in the Japanese cuisine. Focusing on the edible plants, the results of our screening study are reviewed.