Glucosinolates in Crucifer Species Affected by Postharvest Elicitors Â Altered Gas Compositions and Uv-B Irradiation

In this study, the effect of UV irradiation (UV-A, UV-B, and UV-C) on phytochemicals, total phenolics, and antioxidant activity of postharvest pigeon pea leaves was evaluated. The response of pigeon pea leaves to UV irradiation was phytochemical specific. UV-B and UV-C induced higher levels of phytochemicals, total phenolics, and antioxidant activity in pigeon pea leaves compared with UV-A. Furthermore, UV-B irradiation proved to possess a long-lasting effect on the levels of phenolics and antioxidant activity. After adapting for 48 h at 4 °C following 4 h UV-B irradiation, total phenolics and antioxidant activity were approximately 1.5-fold and 2.2-fold increased from 39.4 mg GAE/g DM and 15.0 μmol GAE/g DM to 59.1 mg GAE/g DM and 32.5 μmol GAE/g DM, respectively. These results indicate that UV irradiation of pigeon pea leaves can be beneficial in terms of increasing active components and antioxidant activity.

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

UV-Induced Changes of Active Components and Antioxidant Activity in Postharvest Pigeon Pea [Cajanus cajan (L.) Millsp.] Leaves

Wei¹,

Luo²,

Zhao³

et al. 2013

“…24 Only a limited number of glucosinolate compounds have been shown to respond to enhanced but nonstressing UVB radiation: an increase in 4-(methylsulfinyl)butyl glucosinolate was observed in broccoli, and an increase in benzyl glucosinolate was observed in nasturtium. 25,26 To date, many studies have focused on the effects of exposure to increased levels of UVB radiation on a plant's secondary metabolism and consequently its profile. However, it should be borne in mind that most greenhouse-grown plants are not exposed to high levels of UV radiation because widely used glass and plastic covers are not permeable to UVB and are only slightly permeable to UVA.…”

Section: ■ Introductionmentioning

confidence: 99%

Effects of Developmental Stages and Reduced UVB and Low UV Conditions on Plant Secondary Metabolite Profiles in Pak Choi (Brassica rapa subsp. chinensis)

Heinze

Hanschen

Wiesner-Reinhold

et al. 2018

Pak choi (Brassica rapa subsp. chinensis) is rich in secondary metabolites and contains numerous antioxidants, including flavonoids; hydroxycinnamic acids; carotenoids; chlorophylls; and glucosinolates, which can be hydrolyzed to epithionitriles, nitriles, or isothiocyanates. Here, we investigate the effect of reduced exposure to ultraviolet B (UVB) and UV (UVA and UVB) light at four different developmental stages of pak choi. We found that both the plant morphology and secondary metabolite profiles were affected by reduced exposure to UVB and UV, depending on the plant's developmental stage. In detail, mature 15- and 30-leaf plants had higher concentrations of flavonoids, hydroxycinnamic acids, carotenoids, and chlorophylls, whereas sprouts contained high concentrations of glucosinolates and their hydrolysis products. Dry weights and leaf areas increased as a result of reduced UVB and low UV. For the flavonoids and hydroxycinnamic acids in 30-leaf plants, less complex compounds were favored, for example, sinapic acid acylated kaempferol triglycoside instead of the corresponding tetraglycoside. Moreover, also in 30-leaf plants, zeaxanthin, a carotenoid linked to protection during photosynthesis, was increased under low UV conditions. Interestingly, most glucosinolates were not affected by reduced UVB and low UV conditions. However, this study underlines the importance of 4-(methylsulfinyl)butyl glucosinolate in response to UVA and UVB exposure. Further, reduced UVB and low UV conditions resulted in higher concentrations of glucosinolate-derived nitriles. In conclusion, exposure to low doses of UVB and UV from the early to late developmental stages did not result in overall lower concentrations of plant secondary metabolites.

“…In addition, the leaf extract has been shown to diminish the toxic blood and liver effects induced by diethyl maleate in rats. 13 The therapeutic effects of the T. majus plant are believed to be related to the high levels of glucotropaeolin, 14 carotenoids, 1 vitamin C, and various phenolic compounds, 10,15 primarily flavonoids. 11 Most of the studies on the phytochemical composition of T. majus have been done on leaves.…”

Section: ■ Introductionmentioning

confidence: 99%

Identification of Phenolic Compounds in Petals of Nasturtium Flowers (Tropaeolum majus) by High-Performance Liquid Chromatography Coupled to Mass Spectrometry and Determination of Oxygen Radical Absorbance Capacity (ORAC)

Garzón

Manns

Riedl

et al. 2015

The contents and profile of polyphenols were analyzed in edible petals of nasturtium flowers (Tropaeolum majus) of three colors, and their oxygen radical absorbance capacities (ORAC) were compared. Three primary anthocyanins (ACNs) and 15 non-ACN phenolic compounds including hydroxycinammic acids (HCAs) and flavonoids (myricetin, quercetin, and kaempferol derivatives) were detected. Anthocyanin concentration was within 31.9 ± 21.7 and 114.5 ± 2.3 mg cyanidin-3-glucoside (cy-3-glu)/100 g fresh weight (FW) in yellow and red petals, respectively. The concentration of HCAs varied between 33.3 ± 7.1 and 235.6 ± 8.1 mg chlorogenic acid equivalents/100 g FW for red and yellow flowers, respectively. Red flowers had the highest level of flavonoids (315.1 ± 2.4 mg myricetin equivalents/100 g FW) and the highest ORAC radical-scavenging activity. These results show the diversity and abundance of polyphenolic compounds in nasturtium flowers, which could be the basis for applications in functional foods, cosmetics, and pharmaceuticals.