Sakuranetin, a flavanone phytoalexin from ultraviolet-irradiated rice leaves

Comparative efficaciesin vitroof antibacterial, fungicidal, antioxidant, and herbicidal activities of momilatones A and B

“…Many scientists have attempted to isolate and characterize phytoalexins from rice plants, of which oryzalexins A-D, phytocassanes A-D and EL (Kono et al 1984, Sekido et al 1986, Koga et al 1997, and they are considered as novel antifungal diterpene compounds. A flavanone phytoalexin, sakuranetin that was isolated from ultraviolet irradiated rice leaves, showed great inhibition on spore germination of Pyricularia oryzae with the value of ED 50 (Effective Dose) of about 15 ppm (Kodama et al 1992). Previous research announced that M A and M B are triggered by pathogen infection, including fungi and virus (Cartwright et al 1977, Agrawal et al 2002, Jung et al 2005.…”

“…A large number of phytotoxic substances (allelochemicals) including diterpene and flavanone phytoalexins, which are involved in the defense mechanism of the rice plant have been isolated as phytoalexins such as M A and M B (Figure 1), oryzalexin A-F, phytocassanes A to D and the flavonoid phytoalexin sakuranetin (Cartwright et al 1977, Kodama et al 1992, Kato et al 1993, Tamogani et al 1993, Koga et al 1997, Chung et al 2005. The diterpenoids (M A and M B ) were first isolated by Japanese scientists from rice husks (Kato et al 1973) and indicated by them as potential plant growth inhibitors.…”

Flavonoids from Daphne aurantiaca and Their Inhibitory Activities against Nitric Oxide Production

“…1) and 29 known flavonoids. By comparing physical and spectroscopic data with reported data, the 29 known compounds were identified as chamaechromone (4), 6) neochamaejasmin B (5), 7) neochamaejasmin A (6), 7) 7-methoxy neochamaejasmin A (7), 8) daphnodorin A (8), 9,10) daphnodorin B (9), 9,10) daphnodorin C (10), 10,11) dihydrodaphnodorin B (11), 12) daphnodorin I (12), 13) daphnodorin J (13), 12) afzelechin (14), 14) epiafzelechin (15), 15,16) farrerol (16), 17) naringenin (17), 18) sakuranetin (18), 19) sakuranin (19), 20) genkwanin (20), 21) apigenin (21), 22) kaempferol (22), 23) luteolin (23), 24) Chrysoeriol (24), 25) 7,4Ј-dimethylether-luteolin (25), 21) luteolin-5-O-b-glucoside (26), 26) 5,7,4Ј-trihydroxy-3Ј-methoxyflavone (27), 27) diosmetin (28), 28) 5,3Ј,4Ј-trihydroxy-7-methoxyflavone (29), 29) genk wanin-5-O-b-glucopyranoside (30), 29) 30) and yuankanin (32). 31 (Table 1) were very similar to those of 5-methoxy-2,8-bis-(3,4-dimethoxyphenyl)-2,3-cis-7,8-trans-3,4,6,7-tetrahy...…”

Accumulation of 9- and 13-KODEs in response to jasmonic acid treatment and pathogenic infection in rice

“…The induced accumulation of sakuranetin has been demonstrated in leaves treated with JA 26) and in leaves infected by pathogens such as B. oryzae 11) and Magnaporthe grisea. 24) The accumulation of serotonin has also been reported to be induced by methyl jasmonate treatment and infection by B. oryzae. 11) Collectively, these findings suggest that the induced accumulation of KODEs might be involved in the signal transduction that leads to the accumulation of defensive secondary metabolites.…”

“…7). Sakuranetin is the flavonoid phytoalexin of rice, 24) while naringenin is its immediate precursor. 25) Serotonin is a secondary metabolite inducible in response to a pathogen attack in rice and has been indicated to be incorporated into cell walls as a brown material to form a physical barrier against pathogens.…”