Seasonal variation in phytochemicals and antioxidant activities in different tissues of various Broccoli cultivars

Abstract

Florets, leaves, and stems of twelve commercial broccoli cultivars grown in the spring and fall seasons at the National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Suwon, South Korea were evaluated for glucosinolates, vitamin C, total phenol, and total flavonoid contents and antioxidant activity. The levels of all phytochemicals and antioxidant activity were significantly influenced by cultivar (C), plant part (P), and growing season (S). Among the glucosinolates, glucoraphanin and glucobrassicin were the major constituents. The highest total glucosinolate content was found in the florets of plants grown in both seasons. Phenols and flavonoids were highest levels in leaves, while vitamin C was highest in stems, suggesting that broccoli leaves and stems may be good sources of such phytochemicals. The levels of all phytochemicals were generally higher in florets in the spring than in the fall, but were higher in leaves and stems during the fall than the spring. Furthermore, higher cultivar-dependent and tissue-dependent variation was observed in the spring than in the fall. Total phenol content exhibited a strong positive correlation (r = 0.674**) with antioxidant activity, followed by total flavonoid content (r = 0.497**), indicating their significant contribution to total antioxidant activity.

Seasonal Variation of Health-Promoting Bioactives in Broccoli and Methyl-Jasmonate Pre-Harvest Treatments to Enhance Their Contents

“…These results are in agreement with those obtained by Vallejo et al [ 45 ], who reported that all cultivars analyzed had higher values of TPCs and TFs (measured by HPLC-DAD) in spring than in winter, due to the greater sunlight exposure in spring. Moreover, Shiva et al [ 46 ] found that the average TF contents of florets for the broccoli variety ‘NokJae’ were 3.2 mg CE/g in spring and 2.4 mg CE/g in autumn, showing the strong impact of the season. Moreover, the TPC content was higher in spring than in autumn, with means of 6.7 mg GAE/g and 4.9 mg GAE/g of broccoli florets, respectively.…”

Comparative Phytonutrient Analysis of Broccoli By-Products: The Potentials for Broccoli By-Product Utilization

“…If more of the aerial part of the broccoli plant can be processed for consumption, the waste amount from production would be significantly reduced, realizing additional profit to farmers. Since broccoli leaves and stems are seldom utilized, information on the nutritional benefits and human health-promoting compounds in them is rare, although antioxidant activity, in vitro anticancer growth bioactivity, and the effect of broccoli by-product feeding on lactating performance of dairy cows and meat quality of broiler chickens have been previously reported [ 4 , 5 , 6 , 7 , 8 ]. To stimulate the utilization of broccoli leaf and stem tissues, it is essential to evaluate their human nutritional values.…”

Chemical Composition and Antioxidant Activity in Different Tissues of Brassica Vegetables

“…The content of these compounds in Brassica vegetables varies significantly depending on the genotypes of cultivars, the specific plant tissue, fertilization, growing season, and several other environmental factors [9,20,21,22,23]. For example, significant variation in glucosinolate concentration as well as the content of other compounds has been shown in the same cultivar grown in different seasons [6,24].…”