Variation in flavonoids in a collection of peppers (Capsicum sp.) under organic and conventional cultivation: effect of the genotype, ripening stage, and growing system

Abstract

BACKGROUND In recent years, the acreage used for organic agriculture and the demand for organic fruit and vegetables have increased considerably. Given this scenario, landraces, such as Capsicum landraces, can provide valuable germplasm. Capsicum peppers are very interesting because of their high phenolic content, and particularly their flavonoid content, which provides a high added value. Moreover, the broad genetic diversity in local varieties expands the opportunities for adaptation to organic production and for exploiting genotype × environment interactions to select peppers with the highest phenolic content. RESULTS In this work, the main flavonoids of peppers were exhaustively evaluated over 2 years in a wide collection of heirlooms, both unripe and fully ripe, under organic and conventional cultivation. The genotype and ripening stage contributed to a high degree to the variation in flavonoids. The growing system influenced this variation to a lesser extent. Luteolin and quercetin showed the highest contributions to total phenolic content (70% and > 20%, respectively) at both ripening stages, while myricetin, apigenin, and kaempferol showed lower contributrions. The average flavonoid content was higher in ripe fruits, and organic management significantly increased the accumulation of total flavonoids and luteolin. Positive correlations between flavonoids were found at both ripening stages, especially between main flavonoids luteolin and quercetin and between kaempferol and quercetin (ρ > 0.7). CONCLUSION Genotype × environment interaction enabled the identification of accessions with high flavonoid content grown under organic conditions at both ripening stages, particularly total flavonoids and luteolin at the fully ripe stage. Our results reinforce the importance of a wide genetic variation and of considering different ripening stages and growing conditions for breeding high‐quality peppers. © 2020 Society of Chemical Industry

Antioxidant Profile of Pepper (Capsicum annuum L.) Fruits Containing Diverse Levels of Capsaicinoids

“…From a redox viewpoint, it has been found that reactive oxygen species (ROS) metabolism is also affected during fruit ripening, leading to major changes in total soluble reducing equivalents and the antioxidant capacity in fruits [41]. The profile of the major non-enzymatic antioxidants, including ascorbate, glutathione, carotenoids and polyphenols, has been followed during ripening in pepper fruits [4,11,12,[42][43][44][45][46], but less is known on how enzymatic antioxidants evolve with this physiological process. These enzyme systems basically include superoxide dismutase (SOD), catalase (CAT) and the ascorbate-glutathione cycle as the primary defense barriers against ROS, and some NADP-dehydrogenases as a secondary system to help the antioxidative enzymatic block.…”

Identification of Compounds with Potential Therapeutic Uses from Sweet Pepper (<em>Capsicum annuum</em> L.) Fruits and Their Modulation by Nitric Oxide (NO)

“…Conversely, during ripening, NO content and catalase activity lower [43]. The content of the main non-enzymatic antioxidants (ascorbate, glutathione, carotenoids and polyphenols) has also been investigated in pepper fruit ripening [7,8,28,[44][45][46][47][48][49]. NO treatment was shown to prevent some of the changes undergone by these parameters, thus confirming the delaying effect of the ripening process indicated above [38,50,51].…”

“…Quercetin and derivatives have been already identified in fruits from diverse pepper varieties [8,[61][62][63][64]. However, there is still very little data on the quercetin profile and its role throughout the ripening process in pepper fruits [28,65], and nothing is known about its modulation by NO. This work is the first report of the regulatory events which shape the quercetin content in fruits from a higher plant.…”

Identification of Compounds with Potential Therapeutic Uses from Sweet Pepper (Capsicum annuum L.) Fruits and Their Modulation by Nitric Oxide (NO)

“…This group includes flavonoids such as isoflavones, anthocyanidins, chalcones, and anthocyanins. In general, flavonoids have antibacterial, antifungal, antioxidant, and anticancer effects [ 1 , 8 , 13 , 28 ].…”