Research Paper CNS Activity of Ethanol Extract of Wedelia chinensis in Experimental Animals V. Suresh, R.M. Kumar, A. Suresh, N.S. Kumar, G. Arunachalam and K. Umasankar* College of Pharmacy, J.K.K. Munirajah Medical Research Foundation, Namakkal, India. ABSTRACT: The plant Wedelia chinensis was found to be used by different traditional systems and folklore for the treatment of various disorders. The aim of the present study is to investigate the effect on central nervous system (CNS) of the ethanol extract of Wedelia chinensis whole plant in Swiss albino mice and Wistar rats.The CNS effects were evaluated by general behaviour, exploratory behaviour, muscle relaxant activity and phenobarbitone sodium–induced sleeping time using standard procedures in experimental animal models.The results revealed that the ethanol extract at 200 and 300 mg/kg caused a significant reduction in the spontaneous activity (general behavioural profile), exploratory behavioural pattern (Y–maze and head dip test), muscle relaxant activity (rotarod and traction tests), and significantly potentiated phenobarbitone sodium–induced sleeping time.The results conclude that the extract exhibit CNS depressant activity in tested animal models. KEYWORDS: Wedelia chinensis; muscle relaxant; phenobarbitone-induced sleeping time; CNS depressant activity Introduction Wedelia chinensis (Asteraceae) is a perennial herb of about 0.3 to 0.9 cm height. Leaves are fleshy, usually 4-9 cm long and 2-5 cm wide, irregularly toothed or serrate, usually with a pair of lateral lobes and obviate in shape. Flowers are yellow, tubular in terminal or axillary head and 4-5 cm in diameter. Traditionally the fruits, leaves and stem are used in childbirth and in the treatment of bites and stings, fever and infection. The leaves are used in the treatment of kidney dysfunction, cold, wounds and amenorrhea (Mathew, 1983). The leaves are also used for dyeing hair and for promoting their growth. The tonic of the leaves is used in cough andcephalalgia. Decoction of the plant is used in menorrhagia and skin diseases (Kirtikar and Basu, 1975; Saxenaet al., 1986). The plant has also found its use in inflammations, helmintic diseases and liver disorders (Anonymous, 1983).The decoction of the plant was extensively used by the tribes in Kolli Hills of Namakkal District, Tamilnadu, India, to reduce mental tension and also to induce sleep and the plant affects CNS (Anonymous, 1948).The plant has been used as astringent, bitter, acrid, anti-inflammatory andcardiotonic, and treatment of wounds, seminal weakness and viral-hepatitis (Chopra, 1956; Vaidyaratnam, 1997). An ethanolic (5 %) extract inhibits the growth of Ehrlich’s ascites carcinoma. The extracts of this plant have been tested in experimental animal models for their hepatoprotective effect (Aperset al., 2002), analgesic and anti-inflammatory activity(Sureshkumaret al., 2006) and androgen suppressing activity (Lin et al., 2007)The alcoholic extract of the leaves was found to possess wound healing properties (Vermaet al., 2008; Mishra et al., 2009), antioxidant (Verma and Khosa, 2008) and lipid peroxidation inhibitory activity (Verma and Khosa, 2009) in rats. The plant is traditionally used to reduce mental tension and to induce sleepand scientifically reported to possess antioxidant property which indicates its usefulness in reducing anxiety and stress in emotional conditions. Therefore, in the light of the traditional and reported uses, the present study was undertaken to investigate the CNS activity of the ethanol extract of Wedelia chinensiswhole plant in variousexperimental animal models. Materials and Methods Plant material and extraction The plant was collected from Kolli hills in Salem district, Tamil Nadu, India in December 2006 and identified by a Taxonomistfrom Botanical Survey of India, Coimbatore, Tamilnadu, India and the specimens were deposited in the herbarium of Department of Pharmacognosy, JKK Munirajah Medical Research Foundation College of Pharmacy, Komarapalayam, Tamilnadu, India. One kg of coarsely powdered plant material was successively extracted with three volumes of 95% ethanol for 72 h at room temperature. The whole extract was collected in a 5 litre conical flask, filtered, and the solvent was evaporated to dryness under reduced pressure in rotary evaporator International Journal of Pharmaceutical Sciences and Nanotechnology Volume 3 • Issue 1 • April – June 2010 * For correspondence: K. Umasanker, E-mail: youmasankar@yahoo.co.in 881