Search results for "antifeedant activity"

Guaianolides from the aerial parts of Centaurea hololeuca

2006

Seven guaianolides were isolated from the acetone extract of the aerial parts of Centaurea hololeuca Boiss. The antifeedant activity of the natural compounds (1-7) and of four chloro derivatives (8-11), synthesized from repin (1) and janerin (3) were tested against larvae of Spodoptera littoralis. Cebellin J (6) and chlorojanerin (11) showed significant antifeedant activity at 100 ppm, whereas at this concentration cebellin G (4) and 15-deschloro-15- hydroxychlorojanerin (7) stimulated feeding. Cebellin G (4) stimulated larvae of S. littoralis to feed at low concentration, but deterred feeding at high concentrations. The addition of chlorine to repin (1) resulted in an increase in antifeeda…

Extremely potent antifeedant neo-clerodane derivatives of scutecyprol A

2004

Two known neo-clerodane diterpenoids, scutecyprol A (1) and scutalbin C (2), have been isolated from the acetone extract of the aerial parts of Scutellaria sieberi. The antifeedant activity of scutecyprol A (1), of its 15-oxo derivative (3), and of several halohydrins (4-9), synthesized starting from compounds 1 and 3, against Spodoptera littoralis have been determined and structure-antifeedant relationships are discussed.

Neoclerodanes from Teucrium orientale

2004

Abstract Two new neoclerodane diterpenoids, 6-deacetyl-teucrolivin A (5) and 8beta-hydroxy-teucrolivin B (6), were isolated from the aerial parts of Teucrium orientale, along with four already known neoclerodane diterpenoids, teucrolivin A (1), teucrolivin B (2), teucrolivin C (3) and teucrolivin H (4), previously isolated from Teucrium oliverianum. Their structures were elucidated on the basis of spectroscopic evidence and chemical transformations. Compounds 1-3 were assayed for antifeedant activity against Spodoptera littoralis, S. frugiperda and Heliocoverpa armigera. Teucrolivin A was the most potent of the three compounds tested.

Volatile components and antifeedant activity of the essential oil from Scutellaria hastifolia L.

2009

Sesquiterpenes from Onopordum illyricum and their antifeedant activity

2012

Phytochemical investigation of the acetone extract of the aerial parts of Onopordum illyricum L. afforded five known sesquiterpenoids: compounds 3 and 4 already isolated from O. illirycum, and 8α-[4′-hydroxymethacryloyloxy]-sonchucarpolide (1), 8α-[4′-hydroxymethacryloyloxy]-4-epi-sonchucarpolide (2) and 8-(4′-hydroxymethacryloyl)-dehydromelitensin (5), not previously detected in this species. Compounds 4 and 5 showed moderate antifeedant activity against larvae of Spodoptera littoralis.