Takeshi Matsumoto

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 .

Molluscicidal and insecticidal activities of isobutylamides isolated fromFagara macrophylla

Five isobutylamides were isolated as insect growth inhibitors and toxicants fromFagara macrophylla and identified from their spectroscopic data.

Multichemical resistance of the coniferPodocarpus gracilior (Podocarpaceae) to insect attack

Podocarpus gracilior is resistant in nature to insect attack. Apparently, the resistance ofP. gracilior is due to a multichemical defense mechanism. Chemicals identified as potential components of the multichemical defense are four norditerpenedilactones, including nagilactones, C, D, and F, which cause insect feeding deterrent activity ultimately coupled to an insecticidal activity, and podolide, an insecticide; two nonlethal growth-inhibiting biflavones, podocarpusflavone A and 7″,4′″-dimethylamentoflavone; and the ecdysis-inhibiting phytoecdysone, ponasterone A.

Isolation and structure of hepialone; principal component from male sex scales of Hepialus californicus (Lepidoptera)

Abstract Hepialone, a new sex-pheromonal component produced by the male moth, Hepialus californicus B., was isolated from their hairpencils. The structure was determined to be (2 R )-2,3-dihydro-2-ethyl-6-methyl-4H-pyran-4-one ( 1 ), a new compound despite its simple structure.

Epicatechin can cause the seedling growth inhibitor, nagilactone E, to induce growth stimulation

A possible new role for the flavonoid (−)-epicatechin (II) is described. It has no growth effects on its own, but when it is added to lettuce and rice seeds together with the known seedling growth inhibitor nagilactone E (I), the growth inhibitor activity ofI can cease and growth stimulation can be observed.

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.

Congeners of norditerpene dilactones from Podocarpus nagi

Abstract Three new norditerpene dilactones, 2,3-dehydro-16-hydroxynagilactone F, nagilactone I and 16-hydroxy-nagilactone E were isolated from the root bark of Podocarpus nagi. Their structures were established on the basis of the spectroscopic analyses.

Abyssinin, a potent insect antifeedant from an african medicinal plant, bersama abyssinica

Abstract Chemical investigation of pest insect control agents from the East African Melianthaceae plants has led to the isolation and characterization of abyssinin, a compound which exhibits very strong antifeedant activity against the cotton pest insect, Heliothis zea 1 .

PLUMBAGIN AS A MODEL FOR INSECT ECDYSIS INHIBITORY ACTIVITY

Abstract An insect ecdysis inhibitor has been identified from the African shrub, Plumbago capensis (Plumbaginaceae), as the naphthoquinone “plumbagin”. Plumbagin inhibited ecdysis in four lepidopterous agricultural pest species, as well as chitin synthetase extracted from one of the four, Trichoplusiani . The synthesis and insect growth in hibitory activity of plumbagin and its analogs is discussed.

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.