Pomegranate-derived anthocyanin regulates MORs-cAMP/CREB-BDNF pathways in opioid-dependent models and improves cognitive impairments

BACKGROUND: Pomegranate (Punica granatum) is one of the oldest known edible fruit. Recently, there has been an increased interest in this fruit as a functional food for health benefits due to its use in disease prevention and promotion of overall health wellness.

OBJECTIVE: This study aims to investigate the effects of pomegranate extract for the development of non-opioid substitution therapy for in-vitro and in-vivo studies.

MATERIALS AND METHODS: Anthocyanin contents consisting of cyanidin 3-glucoside, diglucoside, and pelargonidin 3-glucoside, diglucoside were detected and quantified in pomegranate extract using high-performance liquid chromatography. The optimum dosage of the extract was determined based on the regulation of MORs and cAMP proteins in U-87 cells. Co-treatment of the extract with morphine was performed to evaluate its potency in reducing the concentration levels of MORs and cAMP. For animal studies, rats were divided into two major groups representing both acute and chronic morphine-induced treatments and the Morris water maze (MWM) study was employed after treatment for each rat. The rats were sacrificed after the treatments and serum samples were collected to evaluate the levels of CREB and BDNF.

RESULTS: The results indicated that each of the anthocyanin content tested in the study was present in the pomegranate extract. Additionally, in-vitro studies using pomegranate extract treatment showed that the extract was effective in decreasing the MORs and cAMP protein levels in U-87 cells at a concentration of 0.125 mg/mL. The memory impairment based on the MWM study in rats was also subsequently improved after treatment with pomegranate extract as compared to treatment with morphine. The blood serum derived from the rats treated with pomegranate extract also showed a significant decrease in CREB level and an increase in BDNF as compared to rats treated with morphine.

CONCLUSION: In conclusion, this study substantiates the potency of pomegranate extract as a non-opioid substitution therapy for in-vitro and in-vivo studies.