Sulforaphane is Superior to Glucoraphanin in Modulating Carcinogen-Metabolising Enzymes in Hep G2 Cells

Abstract

Glucoraphanin is the main glucosinolate found in broccoli and other cruciferous vegetables (Brassicaceae). The objective of the study was to evaluate whether glucoraphanin and its breakdown product sulforaphane, are potent modulators of various phase I and phase II enzymes involved in carcinogen-metabolising enzyme systems in vitro. The glucosinolate glucoraphanin was isolated from cruciferous vegetables and exposed to human hepatoma cell line HepG2 at various concentrations (0-25 µM) for 24 hours. Glucoraphanin at higher concentration (25 µM) decreased dealkylation of methoxyresorufin, a marker for cytochrome P4501 activity; supplementation of the incubation medium with myrosinase (0.018 U), the enzyme that converts glucosinolate to its corresponding isothiocyanate, showed minimal induction in this enzyme activity at concentration 10 µM. Quinone reductase and glutathione S-transferase activities were unaffected by this glucosinolate; however, supplementation of the incubation medium with myrosinase elevated quinone reductase activity. It may be inferred that the breakdown product of glucoraphanin, in this case sulforaphane, is superior than its precursor in modulating carcinogenmetabolising enzyme systems in vitro and this is likely to impact on the chemopreventive activity linked to cruciferous vegetable consumption.

Sulforaphane and Other Nutrigenomic Nrf2 Activators: Can the Clinician’s Expectation Be Matched by the Reality?

“…Sulforaphane [1-isothiocyanato-(4R)-(methylsulfinyl) butane: CH 3 S(O)(CH 2 ) 4 -N=C=S] is a small (MW = 177.29) aliphatic lipophilic organosulfur molecule which is not present in cruciferous or other plants (Supplementary Data, Figure 1, in Supplementary Material available online at http://dx.doi.org/10.1155/2016/7857186 ). Instead, plants of Brassica genus contain a biologically inactive precursor compound, glucoraphanin (GRN), which is contained within a plant cell vacuole together with an enzyme, myrosinase (MYR), which is separately compartmentalized [ 39 ]. It is when the plant cell ruptures and the GRN and MYR come into contact that sulforaphane is enzymatically produced [ 40 ] (Supplementary Data, Figure 2).…”

Induction of Apoptosis and Cytotoxicity by Isothiocyanate Sulforaphene in Human Hepatocarcinoma HepG2 Cells

“…A number of phytochemicals have been considered as potential cancer chemopreventive agents, e.g., glucosinolates (GLs) ( Figure 1 ), major components found in cruciferous vegetables which over the years have been identified as potential anti-carcinogens against many common cancers [ 4 , 5 , 6 , 7 , 8 ]. GLs are readily hydrolysed upon tissue damage by the myrosinase enzyme into several active compounds, including isothiocyanates that are believed to be responsible for the chemopreventive activity reported in many studies [ 9 , 10 , 11 , 12 , 13 ]. These compounds bring about beneficial changes in cancerous cells providing convincing evidence that isothiocyanates can be potentially developed into anticancer agents of therapeutic benefit to humans.…”

Benzyl sulforaphane is superior to sulforaphane in inhibiting the Akt/MAPK and activating the Nrf2/ARE signalling pathways in HepG2 cells

“…gemmifera Zenker ) and cabbage ( Brassica oleracea L. var. capitata L), and has an indirect antioxidant activity . A line of evidence has dissected that the antioxidant and antitoxic characteristics of SFN are most easily to involve in the activation of the Nrf2 gene in experimental models .…”

“…capitata L), and has an indirect antioxidant activity. [17,18] A line of evidence has dissected that the antioxidant and antitoxic characteristics of SFN are most easily to involve in the activation of the Nrf2 gene in experimental models. [19] Moreover, it has been reported that SFN has chemotherapeutic properties including antiproliferative properties, the blockade of angiogenesis and induction of tumour cell apoptosis.…”