doi: 10.1111/j.1472-8206.2005.00376.x ORIGINAL ARTICLE Chemopreventive efficacy and anti-lipid peroxidative potential of Jasminum grandiflorum Linn. on 7,12-dimethylbenz(a)anthracene-induced rat mammary carcinogenesis K. Kolanjiappan, S. Manoharan* Department of Biochemistry, Annamalai University, Annamalainagar-608002, India INTRODUCTION Breast cancer accounts for the highest morbidity and mortality in women worldwide, and approximately 910 000 cases of breast cancer and 376 000 deaths are reported every year in the world [1]. Breast cancer is the second most commonly diagnosed cancer among American women, and annually 200 000 women are diagnosed with and 40 000 women die from this cancer [2]. In India, breast cancer is the second most common cancer after cervix, where 70 000 new cases of breast cancer and 35 000 deaths due to this cancer are reported every year [3]. The factors that increase the risk of breast cancer include the first-degree relative with breast cancer, early menarche, late menopause, nulli- parity or bearing the first child at a late age, overweight after menopause, certain types of benign breast diseases, alcohol consumption and long-term use of menopausal estrogen replacement therapy [4]. 7,12-dimethyl- benz(a)anthracene (DMBA), the polycyclic aromatic hydrocarbon, is an immunosuppressor and potent organ-specific carcinogen [5]. The DMBA-induced mam- mary carcinoma appears to arise from the ductal elements of the mammary gland. Disturbances in oxidant and antioxidant status have been implicated in the pathogenesis of several diseases including post-ischemic trauma, neurodegenerative dis- orders and cancer. Profound studies have highlighted the role of reactive oxygen species in the multi-stage events of carcinogenesis. Uptake of antioxidants by tumor tissue to reduce the reactive oxygen species production could be instrumental to control neoplastic transformation [6]. In carcinogenesis, high flux of reactive oxygen species (O  2 , HO • ,H 2 O 2 , etc.) can potentiate the process of biomem- brane lipid peroxidation and thereby causing alteration in the structural integrity and function of cell membrane [7]. Keywords antioxidants, breast cancer, 7,12-dimethylbenz(a) anthracene, Jasminum grandiflorum, lipid peroxidation Received 13 June 2005; revised 5 July 2005; accepted 15 September 2005 *Correspondence and reprints: manshisak@yahoo.com ABSTRACT The aim of this study was to investigate the chemopreventive efficacy and anti-lipid peroxidative potential of Jasminum grandiflorum Linn. on 7,12-dimethylbenz(a) anthracene (DMBA)-induced rat mammary carcinogenesis. Mammary tumors were developed by a single subcutaneous injection of 25 mg DMBA in 1 mL emulsion of sunflower oil and physiological saline. The tumor incidence and tumor volume that formed in the breast were determined. Oral administration of ethanolic extract of J. grandiflorum flowers (JgEt) at a dose of 300 mg/kg body weight for 14 weeks to DMBA-injected animals completely prevented the formation of tumors in the pre- initiation period. JgEt also exerted significant anti-lipid peroxidative effect and improved the antioxidant defense system in DMBA-treated rats. The results of this study clearly indicate that JgEt has potent chemopreventive efficacy in experimental mammary carcinogenesis and further studies are warranted to isolate and charac- terize the bioactive principle from JgEt. Ó 2005 Blackwell Publishing Fundamental & Clinical Pharmacology 19 (2005) 687–693 687