Effect of Naringin Radical Formed by Peroxidase on Chlorophyll Degradation during Storage of Citrus nagato-yuzukichi Fruit

Abstract

Free radical formation from flavonoids by peroxidase action and changes in flavonoid levels and peroxidase activity during storage were determined to clarify the involvement of naringin radical in chlorophyll (Chl) degradation in stored green Nagato-yuzukichi (Citrus nagato-yuzukichi hort. ex Y. Tanaka) fruit. Chl a was degraded by peroxidase-hydrogen peroxide system not in the presence of hesperidin but with naringin. However, radical formation of both naringin and hesperidin, which were the main flavonoids in the flavedo of Nagatoyuzukichi fruit, with peroxidase-mediated oxidation was found by electron spin resonance analysis. The naringin radical, which was formed by a radical forming reagent, potassium ferricyanide, was related to the formation of 13 2 -hydroxychlorophyll (OHChl) with Chl a degradation, whereas the hesperidin radical hardly affected OHChl a formation. In addition, superoxide dismutase did not inhibit Chl a degradation by naringin radical formed by potassium ferricyanide. In Nagato-yuzukichi fruit, Chl-degrading peroxidase activity increased considerably during storage at 20°C, with a peak value on day 6 of storage in accordance with decrease in Chl content, after which it decreased. The contents of naringin and hesperidin, especially the former, decreased during storage at 20°C, but afterwards increased slightly. These findings suggest that the naringin radical formed by peroxidase could be partly involved in Chl degradation during storage in Nagato-yuzukichi fruit.

Postharvest senescent dark spot development mechanism of Musa acuminata (“Khai” banana) peel associated with chlorophyll degradation and stomata cell death

“…Likewise, high activity of chlorophyll‐degrading peroxidase was detected from small green to white stages of strawberry which corresponded with the diminishing of chlorophyll content and the drop in chlorophyll‐degrading activity as it ripened (Martinez et al., 2001). This chlorophyll‐degrading peroxidase has been claimed to be engaged in in vitro chlorophyll degradation of horticultural crops by oxidized phenolics compounds with the presence of hydrogen peroxide and formation of a phenoxy radical which directly breaks down chlorophyll‐a into a colorless compound (Yamauchi, 2015; Yamauchi et al., 2012). The complete disappearance of the greenish color of chlorophyll occurs at the late stage of the chlorophyll breakdown pathway to commonly yield short‐lived colorless fluorescent catabolites (FCCs) intermediates, which are further isomerized to form stable nonfluorescent chlorophyll catabolites (NCCs) as end products as found in ripened apples and pears (Moser et al., 2009).…”

Quality Maintenance of Postharvest Horticultural Crops by Stress Treatments and Approach for the Elucidation of Its Mechanism

“…Most of these compounds related to peroxidase-dependent Chl degradation are phenolic compounds having a hydroxyl group at p-position. Consequently, p-coumaric acid and the flavonoids apigenin and naringenin, especially the former, which is (Kato and Shimizu, 1985;Yamauchi and Watada, 1994;Yamauchi et al, 2004Yamauchi et al, , 2012. According to the inhibitory effects of Tiron, nitroblue tetrazolium, MnCl 2 , AsA, and n-propyl gallate on peroxidase-mediated Chl degradation, we demonstrated that a phenoxy radical and/or a superoxide anion radical (·O 2 − ) could be involved in Chl degradation.…”

“…The protein precipitated by 45-60% saturated ammonium sulfates hardly included Chlase activity and was suitable for PPH determination. PPH activity in broccoli florets treated with UV-B was repressed for the first 2 days of storage at 15°C but gradually increased with yellowing of control broccoli florets (Aiamla-or et al, 2012).…”

“…The expressions of BoCLH2 and BoCLH3 in broccoli florets with UV-B treatment were more up-regulated than in the control during storage at 15°C. In contrast, the expression levels of BoPPH and BoPAO (pheide a oxygenase gene) during storage were suppressed by UV-B treatment, which could suggest that the up-regulation of these Chl-degrading enzyme genes could be delayed by UV-B treatment, resulting in the suppression of floret yellowing in stored broccoli (Aiamla-or et al, 2012).…”

“…To elucidate which phenoxy radical is related to peroxidase-mediated Chl degradation, radical formation from flavonoid by peroxidase was determined using the extract of flavedo tissue of green Nagato-yuzukichi fruit (Yamauchi et al, 2012). The radical formation of both naringin and hesperidin, which are the main flavonoids in the flavedo, with peroxidase-mediated oxidation was found by electron spin resonance analysis.…”