Utilization of the ability to induce activation of the nuclear factor (erythroid-derived 2)-like factor 2 (Nrf2) to assess potential cancer chemopreventive activity of liquorice samples

• Main Authors: Basar, N., Nahar, L., Oridupa, O. A., Ritchie, K. J., Talukdar, A. D., Stafford, A., Kushiev, H., Kan, A., Sarker, S. D.
• Format: Article
• Published: John Wiley and Sons Ltd 2016
• Subjects: QD Chemistry
• Online Access: http://eprints.utm.my/id/eprint/72179/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982224710&doi=10.1002%2fpca.2616&partnerID=40&md5=9b002d93328eef2ca69d251110b56767
• Institution: Universiti Teknologi Malaysia

Introduction: Nuclear factor (erythroid-derived 2)-like factor 2 (Nrf2) is a transcription factor that regulates expression of many detoxification enzymes. Nrf2-antioxidant responsive element (Nrf2-ARE) signalling pathway can be a target for cancer chemoprevention. Glycyrrhiza glabra, common name, ‘liquorice’, is used as a sweetening and flavouring agent, and traditionally, to treat various ailments, and implicated to chemoprevention. However, its chemopreventive property has not yet been scientifically substantiated. Objective: To assess the ability of liquorice root samples to induce Nrf2 activation correlating to their potential chemopreventive property. Methods: The ability of nine methanolic extracts of liquorice root samples, collected from various geographical origins, to induce Nrf2 activation was determined by the luciferase reporter assay using the ARE-reporter cell line, AREc32. The antioxidant properties were determined by the 2,2-diphenyl-1-picryhydrazyl (DPPH) and the ferric-reducing antioxidant power (FRAP) assays. Results: All extracts exhibited free-radical-scavenging property (RC50 = 136.39–635.66 µg/mL). The reducing capacity of ferrous ion was 214.46–465.59 μM Fe(II)/g. Nrf2 activation indicated that all extracts induced expression of ARE-driven luciferase activity with a maximum induction of 2.3 fold relative to control. These activities varied for samples from one geographical location to another. Conclusions: The present findings add to the existing knowledge of cancer chemoprevention by plant-derived extracts or purified phytochemicals, particularly the potential use of liquorice for this purpose.