Sulforaphane, polyphenols and related anti-inflammatory and antioxidant activities changes of Egyptian broccoli during growth

Abstract

Broccoli (Brassica oleraccea var italica L.) was introduced as a food cultivar that rich in many different functional phytochemicals. 1-Isothiocyanato-4-methylsulfinylbutane (sulforaphane) has been shown before to down-regulate inflammatory cyclooxygenase-2 (COX-2) expression in mammalian cells. On the other hand, polyphenols equivalent to tannic acid has been identified as an antioxidant due to radical scavenging possibilities. Extracts were prepared by methylen chloride from broccoli seeds, 7-day old sprouts and mature fresh broccoli grown in Egypt. Sulforaphane contents were determined using reverse phase-high performance liquid chromatography, whereas polyphenols were evaluated spectrophotometrically by the method of Folin–Ciocalteau. Anti-inflammatory and antioxidant activities of extracted components were investigated by Cyclooxygenase (COX) inhibition and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, respectively. Results indicated that mature broccoli has the less efficient composition of bioactive compounds therefore, the health benefits decreased, whereas much of polyphenols (equivalence to tannic acid, tannic acid equivalents (TAE)) was in seeds and sulforaphane in 7-day old sprouts by 1.474 ± 0.15 mg TAE/g FW and 465.7 ± 7.16 μg/g FW, respectively. Regarding the concentrations of bioactive compounds, the highest antioxidant activity was determined in seeds extract (IC50 = 64 ± 3.2 μg/mL) and the efficient anti-inflammatory activity was determined in 7-day old sprouts extract (IC50 = 81 ± 4 μg/mL). Pure sulforaphane and tannic acid solutions were tested to investigate the correlation of extracted materials to their activities, sulforaphane has no DPPH scavenging activity and tannic acid has no COX inhibition effect. The intention to replace drugs to maximize anti-inflammatory and antioxidant activities with increasing therapeutic safety.