Hepatoprotective effects of raspberry (Rubus coreanus Miq.) seed oil and its major constituents

Raspberry seed is a massive byproduct of raspberry juice and wine but usually discarded. The present study employed a microwave-assisted method for extraction of raspberry seed oil (RSO). The results revealed that omega-6 fatty acids (linoleic acid and γ-linolenic acid) were the major constituents in RSO. Cellular antioxidant enzyme activity such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were investigated in HepG2 cells treated with RSO. Induction of the synthesis of several antioxidants in H₂O₂-exposed HepG2 cells was found. RSO increased the enzyme activity of SOD, CAT, and GPx in H₂O₂-exposed HepG2. Furthermore, RSO inhibited the phosphorylation of upstream mitogen-activated protein kinases (MAPK) such as c-Jun N-terminal kinase (c-JNK) and extracellular signal-regulated kinase (ERK). Taken together, the possible mechanisms to increase antioxidant enzyme activities in HepG2 may through the suppression of ERK and JNK phosphorylation. Raspberry seed oil exhibited good effects on the activities of the intracellular antioxidant enzymes and seems to protect the liver from oxidative stress through the inhibition of MAPKs.