Isovitexin‐2″‐O‐β‐[6‐O‐E‐p‐coumaroylglucopyranoside] from UV‐B irradiated Leaves of Rice, Oryza sativa L. Inhibits Fertility of Helicoverpa armigera

Abstract

UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1x concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (P<0.001) when added to insect diets at 18 nmol gFW(-1) (14 ppm). A similar antifertility effect was observed when only the male partner consumed diet containing flavonoid IIa, indicating that the reduced fertility may be male specific. In contrast, the fecundity and fertility of insects eating diets containing the closely related flavonoids, isoorientin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside] or isoorientin-2''-O-beta-[6-O-E-p-feruloylglucopyranoside], were not significantly different to control diets.

Dissection of genotype–phenotype associations in rice grains using metabolome quantitative trait loci analysis

“…It has been suggested that flavones in cereals play several roles, including protection from environmental stress and plant‐herbivores interaction (Adjei‐Afriyie et al. , 2000; Caasi‐Lit et al. , 2007).…”

“…Analysis of the rice grain metabolome revealed that rice seeds produce several flavone glycosides with apigenin, chrysoeriol and tricin aglycone moieties (Besson et al, 1985). It has been suggested that flavones in cereals play several roles, including protection from environmental stress and plant-herbivores interaction (Adjei-Afriyie et al, 2000;Caasi-Lit et al, 2007). The natural variations in the flavone glycoside content in rice is of considerable interest because constitutive production of flavones is essential for the protection of grains from environmental stress, but their composition could vary among the different rice varieties to prevent damage from herbivores by changing an interaction with herbivores.…”

Isoorientin Reverts TNF-α-Induced Insulin Resistance in Adipocytes Activating the Insulin Signaling Pathway

“…The strong induction of glucose uptake exerted by ISO on both insulin responsive or insensitive adipose cells, coupled with its broad distribution in plants, notably in food plants (41,42), and its proved in vitro production (43) makes this natural compound a promissory candidate to "mow the GRAS" (10) in the two main types of diabetes mellitus.…”

Identification of a Bifunctional Maize C- and O-Glucosyltransferase

“…In general, plants accumulate flavonoids in vacuoles as O-glycoside derivates; however, bryophytes, ferns, gymnosperms, and several angiosperms also produce flavonoid C-glycosides (10,11). In particular, cereals like wheat, rice, and maize mainly accumulate C-glycosyl flavones that are involved in protection against UV-B radiation and defense against pathogens (12)(13)(14). For example, maysin, the C-glycosyl flavone predominant in silk tissues of some maize varieties, is a natural insecticide against the corn earworm Helicoverpa zea (15,16), whereas C-glycosyl flavonoids identified in cucumber leaves act as phytoalexins in defense against powdery mildew fungi (17,18).…”