Romanian Biotechnological Letters Vol. 18, No.1, 2013 Copyright © 2013 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER Romanian Biotechnological Letters, Vol. 18, No. 1, 2013 7995 ANTICANCER ACTIVITIES OF EXTRACTS OF Peristrophe bicalyculata (RETZ) NEES Received for publication, September 20, 2012 Accepted, November 20, 2012 ABDULAZEEZ, MANSURAH, A. 1 , SANI IBRAHIM 1 , AMEH, D.A. 1 , AYO, J.O. 2 , CARVALHO, L.J.C 3 1 Department of Biochemistry, Faculty of Sciences, Ahmadu Bello University, Zaria, Kaduna State, Nigeria 2 Department of Physiology and Pharmacology, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Kaduna State, Nigeria 3 Embrapa Genetic Resources and Biotechnology, Laboratory of Biochemistry and Biophysics carvalho@cenargen.embrapa.br Corresponding author: mabdulazeez@abu.edu.ng , Tel.: +234-803-450-9063 Abstract The anticancer activity of leaf extracts of Peristrophe bicalyculata was evaluated. Results showed that the methanolic ethylacetate fraction with an IC 50 of 15.60 ± 0.52 µg/ml was potentially very toxic against human mouth epidermal carcinoma (KB) cells. After partial purification of the methanolic ethylacetate fraction, seven fractions were obtained; five of which were inactive (IC 50 values above 500 μg/ml) and one moderately toxic (IC 50 = 235 ± 33.05 µg/ml), hence not considered. The IC 50 value of the most cytotoxic fraction (fraction 5) (3.50 ± 0.21 µg/ml) was not different from that of cisplastin (3.32 ± 0.09 µg/ml), but was significantly (P<0.05) higher than the value obtained for doxorubicin (0.43 ± 0.02 µg /ml) and vincristine (0.05 ± 0.01µg/ml). The partially-purified fraction induced apoptosis in KB cells after 24 and 48 hours in a dose-dependent manner. The percentage of apoptotic cells in cultures treated with this fraction was significantly (P<0.05) higher than that in control cultures, but lower than cultures treated with cisplastin. The GC-MS analysis of the fraction indicated an abundance of andrographolide 2(3H)-furanone and aromadendrene oxide, both of which possess anticancer properties. The results provide scientific evidence supporting the anticancer activity of the methanolic ethylacetate fraction of the plant. In conclusion, the methanolic ethylacetate fraction of Peristrophe bicalyculata is a potential source of chemotherapeutic agent. Keywords: Peristrophe bicalyculata, Sulphorhodamine B assay, anticancer, apoptosis, necrosis, andrographolide Introduction Peristrophe bicalyculata (Retz) Nees belongs to the family Acanthaceae. It is native to warm tropical regions of Africa, including Mauritania, Niger, Nigeria, India, Burma and Thailand. The Hausas in Northern Nigeria call it ‘tubanin dawaki’ meaning ‘flower of the horse’. In Berer and Wolof languages of Senegal, it is called ‘buben’ or ‘moto’ (1). In the Indore district of India, the local name is ‘chotiharjori’(2).The leaves of the plant have analgesic, antipyretic, anti-inflammatory activity (3), antibacterial and fungistatic properties (1,4). In South-west Nigeria, the leaves are used for the treatment of hypertension and cardiovascular-related diseases (5). Studies have demonstrated the anticancer activity of oils from Peristrophe