Pak. J. Pharm. Sci., Vol.29, No.5(Suppl), September 2016, pp.1787-1794 1787 In vitro antioxidant and hepatoprotective activities of Paeonia emodi (Wall.) rhizome methanol extract and its phenolic compounds rich fractions Ikram Ilahi 1 *, Jahangir Khan 2 , Rukhsana Ghaffar 2 , Akhtar Hussain 1 , Kausar Rahman 2 , Sara Wahab 1 , Razia Begum 1 , Maryum Hidayatullah 1 , Asma Amin 1 , Sobia 1 , Muhammad Shoaib 1 , Izhar Ahmad 4 , Dawood Ali 3 and Liaqat Zeb 3 1 Department of Zoology, University of Malakand, Chakdara, Lower Dir, Khyber Pakhtunkhwa, Pakistan 2 Department of Pharmacy, University of Malakand, Chakdara, Lower Dir, Khyber Pakhtunkhwa, Pakistan 3 Department of Biotechnology, University of Malakand, Chakdara, Lower Dir, Khyber Pakhtunkhwa, Pakistan 4 Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan Abstract: The present study aimed to quantify the total phenolic content in Paeonia emodi rhizome methanol extract and its fractions and then evaluate the in vitro antioxidant and hepatoprotective activities of fractions rich in phenolic compounds. Maximum quantity of total phenolic content was observed in butanol (112.08±5.5 mg GAE/g dw) and chloroform fraction (107.0±3.5 mg GAE/g dw) followed by methanol extract (94.2±4.4 mg GAE/g dw), aqueous fraction (92.9±2.5 mg GAE/g dw), ethyl acetate (62.3±8.3 mg GAE/g dw) and n-hexane fraction (51.6±7.2 mg GAE/g dw). The fractions rich in total phenolic content were evaluated for in vitro antioxidant activity based on 2, 2-diphenyl-1-picryl- hydrazyl (DPPH) scavenging assay. The butanol and chloroform fraction showed significantly (P<0.05) higher radical scavenging activity with IC 50 values of 6.5 and 7.05±2.5 ppm respectively. Positive correlation (R square=0.95) was observed between total phenolic content and in vitro antioxidant activity. The fractions rich in phenolic compounds were also evaluated for their hepatoprotective activity in paracetamol intoxicated mice. Five days oral administration of these fractions at a dose of 300 mg/kg body weight restored the serum ALT, AST and ALP levels of paracetamol intoxicated mice to normal level. From the results of the present research it was concluded that the butanol and chloroform fractions of P. emodi rhizome methanol extract are rich in phenolic compounds and strong antioxidant and effective in attenuation of hepatotoxicity. Keywords: Total Phenolic content, DPPH, antioxidant, liver. INTRODUCTION Liver is an internal vital organ associated with digestive system and responsible for a wide range of functions. It is involved in formation of coagulation factors, storage of vitamins and irons, filtration of toxin out of the blood, storage of blood, metabolism of foreign chemicals, proteins, carbohydrates, fats and hormones (Guyton and Hall, 1996). Liver is important for detoxification of xenobiotic agents (Muthulingam, 2010). Several factors such as excessive use of alcohol, hepatitis infections, fats accumulation, cancer and frequent exposure to toxic chemicals and drugs lead to liver injury. It has been reported that 50% of all acute hepatic failure is due to drug induced liver injury (Ostapowicz et al., 2002). Paracetamol (PCM) is one of the commonly known analgesic drugs used for relieving pain and fever (Rosa et al., 2006). Continuous use or overdosing of PCM leads to hepatotoxicity. Hepatotoxicity following PCM ingestion is due to the production of a highly reactive PCM metabolite, N-acetyl-p-benzoquinonimine (NAPQI). It is synthesized through the cytochrome P4 50 group of enzymes in the liver. NAPQI is usually converted to a non-toxic or safe form after its conjugation with glutathione (GSH) which is then removed by the kidney. NAPQI accumulation results in the excessive generation of reactive oxygen species (ROS) and ultimately liver damage (Ojo et al., 2006). ROS are highly reactive radicals due to possession of unpaired electrons which include superoxide ion, hydroxyl radical and nitric oxide radical, and non-radicals such as peroxynitrite, hydrogen peroxide, hypochlorous acid and singlet oxygen (Vara and Pula, 2014). In living organisms, ROS are produced as a byproduct during oxygen metabolism (Devasagayam et al., 2004) or due to exposure to certain environmental factors such as sunlight, ultraviolet light, ionizing radiation and toxic chemicals (Gyamfi et al., 1999). ROS is important in regulation of various physiological functions such as growth, apoptosis, blood pressure, and cognitive and immune functions (Krause and Bedard, 2008). When in excess, ROS may oxidize and damage biological molecules such as DNA, proteins and lipids by extracting electron from them for attaining stability which may result in mutation, carcinogenesis and other degenerative diseases (Droge, 2002). Oxidation of the membrane proteins and or lipids of hepatocytes due to ROS may *Corresponding author: e-mail: ikramilahi@yahoo.com