Protective effect of coconut water concentrate and its active component shikimic acid against hydroperoxide mediated oxidative stress through suppression of NF-κB and activation of Nrf2 pathway.
BACKGROUND
Conventionally coconut water has been used as an 'excellent hydrating' drink that maintain the electrolyte balance and help in treating diverse ailments related to oxidative stress including liver function. The present study was aimed to elucidate whether and how the coconut water concentrate (CWC) and its major active phytoconstituent shikimic acid (SA) can effectively protect murine hepatocytes from the deleterious effect of hydroperoxide-mediated oxidative stress.


METHODS
Bioactivity guided fractionation of CWC resulted in the isolation of a couple of known compounds. Freshly isolated murine hepatocytes were exposed to hydrogen peroxide (H2O2) (1 and 3mM) in the presence or absence of CWC (200 and 400 μg/ml) and SA (40 μM) for the determination of antioxidative, DNA protective, cellular ROS level by modern methods, including immunoblot and flowcytometry to find out the possible mechanism of action.


RESULTS
Pre-treatment of hepatocyte with CWC and SA showed significant prevention of H2O2-induced intracellular ROS generation, nuclear DNA damage along with the formation of hepatic TBARS and cellular nitrite. Further, the H2O2 induced cell death was arrested in the presence of CWC through the inhibition of CDC42 mediated SAPK/JNK pathways and activation of other molecules of apoptotic pathways, including Bax and caspase3. Moreover, CWC and SA help in maintaining the GSH level and endogenous antioxidants like Mn-SOD, to support intracellular defense mechanisms, probably through the transcriptional activation of Nrf2; and inhibition of nuclear translocation of NF-κB.


CONCLUSIONS
CWC and its active components SA reversed the H2O2 induced oxidative damage in hepatocytes, probably through the inhibition of NF-κB, with the activation of PI3K/Akt/Nrf2 pathway and reduction of apoptosis by interfering the SAPK/JNK/Bax pathway.
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Krishnendu
K
Manna
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Amitava
A
Khan
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Dipesh
D
Kr Das
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Swaraj
S
Bandhu Kesh
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Ujjal
U
Das
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Sayan
S
Ghosh
Department of Food & Nutrition, Barrackpore Rastraguru Surendranath College, North 24, Parganas 700120, West Bengal, India.
Rakhi
R
Sharma Dey
Cancer Biology & Inflammatory Disorder Division, Indian Institute of Chemical Biology, Kolkata 700032, West Bengal, India.
Krishna
K
Das Saha
Radiation Biology Division, UGC-DAE Consortium for Scientific Research, Kolkata Centre, Bidhan Nagar, Kolkata 700098, West Bengal, India.
Anindita
A
Chakraborty
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India.
Sreya
S
Chattopadhyay
Department of Physiology, University of Calcutta, 92, A.P.C Road, Kolkata 700009, West Bengal, India. Electronic address: sanjitdey@gmail.com.
Sanjit
S
Dey
ICMR Virus Unit, ID & BG Hospital, GB-4, First Floor, 57 Dr. Suresh C Banerjee Road, Beliaghata, Kolkata 700010, West Bengal, India.
Debprasad
D
Chattopadhyay
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D003059:Cocos / Q000737:chemistry*; D004249:DNA Damage / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D022781:Hepatocytes / Q000187:drug effects* / Q000473:pathology; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000633:toxicity; D051379:Mice; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D012765:Shikimic Acid / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
D000975:Antioxidants; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D012765:Shikimic Acid; D006861:Hydrogen Peroxide
Apoptosis; Coconut water concentrate; Ethnomedicine; Shikimic acid; Signal transduction