Protective effects of turmeric extract, curcumin, demethoxycurcumin, bis-demethoxycurcumin, and ar-turmerone from Curcuma longa L. rhizomes on acetaminophen-induced hepatotoxicity in HepG2 cells

Objective: To assess the effects of turmeric extract and its compounds on oxidative stress, inflammation, and apoptosis in acetaminophen-induced liver injury. Methods: HepG2 cells were administered with acetaminophen (40 mM) to induce hepatotoxicity, followed by treatment with turmeric extract and its isolated compounds including curcumin, demethoxycurcumin, bis -demethoxycurcumin and ar-turmerone at 5, 25, and 125 μg/mL. IL-1β, IL-6, and IL-10 levels were quantified with ELISA kits. Further, qRT-PCR was used to analyze the mRNA expression of JNK, Casp-9 , and Casp-3. Meanwhile, the levels of nitric oxide and lactate dehydrogenase were analyzed using colorimetric assay. Results: Acetaminophen administration caused an increase in the levels of lactate dehydrogenase, nitric oxide, IL-1β, IL-6, and the mRNA expression of JNK, Casp-9 , and Casp-3 in HepG2 cells while reducing IL-10 levels. Treatment with turmeric extract, curcumin, demethoxycurcumin, bis -demethoxycurcumin, and ar-turmerone lowered IL-1β, IL-6, nitric oxide, and lactate dehydrogenase levels, downregulated the mRNA expression of JNK, Casp-9 , and Casp-3 , and increased IL-10 levels. Conclusions: Turmeric extract and its compounds have significant hepatoprotective activity and could be further explored for the treatment of liver damage.