Objective: To determine the gene expression of antioxidant enzymes by hemp seed extracts
in human hepatoma (HepG2) cells. Methods: Ethanol and supercritical fluid (SF) extracts
obtained from de-hulled hemp seed were used for the evaluation of in vitro antioxidant
activity and gene expression of antioxidant enzymes. In vitro antioxidant activities of the
samples evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-
ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging assays.
The expression of antioxidant enzymes such as superoxide dismutase (SOD), glutathione
peroxidase (GPx) and catalase (CAT) in HepG2
cells was evaluated by real-time PCR. Results:
In the antioxidant assay, SF extract of hemp seed exhibited higher ABTS and DPPH radical
scavenging activities (IC50 of 66.6 µg/mL and 9.2 mg/mL, respectively) than ethanol extract.
The results of antioxidant enzyme expression in real-time PCR study revealed the H2O2 (200
µM) challenged HepG2 cells reduced the expression of enzymes such as SOD, GPx and CAT.
However, the cells treated with ethanol and SF extracts were up-regulated the expression of
antioxidant enzymes in concentration dependent manner. When compared to ethanol extract,
the SF extract exhibited higher activity in the expression of all the antioxidant enzymes
at the concentration of 500 µg/mL. Conclusion: In conclusion, the findings of our study
demonstrated that the hemp seed effectively inhibited H2O2 mediated oxidative stress and may
be useful as a therapeutic agent in preventing oxidative stress mediated diseases