Effect of elevated carbon dioxide (CO2) on phenolic acids, flavonoids, tocopherols, tocotrienols, γ-oryzanol and antioxidant capacities of rice (Oryza sativa L.)

Polyphenols in whole rice grain: Genetic diversity and health benefits

“…The increase of CO 2 concentration in the air will affect the growth of crops, yield, and even the quality of the product. When rice plants were grown in two levels of atmospheric CO 2 (375 and 550 lmol/ml), the total phenolic, and total flavonoid content of all rice milling fractions in the higher CO 2 level decreased about 3-18%, and 8-14%, respectively, with the highest reduction of sinapic acid (167%), p-hydroxybenzoic acid (100%) and tricin (12%) in brown rice, white rice and rice bran, respectively, compared to those in normal CO 2 level (Goufo et al, 2014). How to mitigate the effects of climate change while improving nutraceutical property in whole grain rice needs to be further addressed.…”

“…The content of hydroxybenzoic acids is very low in rice grain, while the content of hydroxycinnamic acid is high with ferulic acid the most abundant followed by p-coumaric acid and sinapic acid, both of which are present as cis-and trans-isomers in rice grain (Park et al, 2012;Shao et al, 2014a). Sinapic acid and p-hydroxybenzoic acid are significantly reduced with increase of CO 2 concentration in brown and white rice grain (Goufo et al, 2014). Protocatechuic and caffeic acid could help the rice plant absorb and utilize precipitated apoplasmic Fe from root surface (Bashir et al, 2011).…”

“…The bound phenolic in rice husk is unlike that in rice grain. The p-coumaric acid is the most abundant, followed by ferulic acid (Goufo et al, 2014). The p-hydroxybenzoic, vanillic and syringic acids exhibited the highest content at maturity or fully ripe stage (Butsat, Weerapreeyakul, & Siriamornpun, 2009).…”

“…The separation of phenolic components of cereal grains is mainly performed by reverse phase HPLC with C18 column as stationary phase and acetic acid/ methanol/ water or trifluoroacetic acid/ acetonitrile/ water as mobile phase, detected by photo diode array (PDA) detector, and confirmed by mass spectroscopy (Goufo et al, 2014;Shao et al, 2014aShao et al, , 2014b.…”

Elevated CO<sub>2</sub> Levels Affect Phytochemicals and Nutritional Quality of Food Crops

“…For example, elevated CO 2 produced low phenolic accumulation in needles of pine [48] and Norway spruce [63]. It has also been shown to reduce the quality of rice grains as measured by the contents of phytochemicals including total phenolics, flavonoids, tocopherol and tocotrienols [64]. In addition, it is not unusual to find contrasting results of CO 2 effects reported in the same species.…”