Callous Cultures of C. peruvianus 149 Applied Biochemistry and Biotechnology Vol. 104, 2003 149 *Author to whom all correspondence and reprint requests should be addressed. Copyright © 2003 by Humana Press Inc. All rights of any nature whatsoever reserved. 0273-2289/03/104/0149/$20.00 Alkaloid Production by Callous Tissue Cultures of Cereus peruvianus (Cactaceae) ARILDO J OSÉ BRAZ DE OLIVEIRA 1 AND MARIA DE FÁTIMA PIRES DA SILVA MACHADO* ,2 Departments of 1 Pharmacy and Pharmacology and 2 Cell Biology and Genetics, State University of Maringá, 87020-900 Maringa PR Brazil, E-mail: mfpsmachado@uem.br Received September 2001; Revised August 2002; Accepted September 2002 Abstract The morphologically undifferentiated cells of nonregenerant callous tis- sue of Cereus peruvianus cultured in the original medium and in medium supplemented with tyrosine were used as an alkaloid source. Comparison of alkaloid production by C. peruvianus plants and by callous tissues indicated that alkaloid levels were almost twice as high in callous tissues as in shoots of C. peruvianus plants. The ratio of alkaloid concentration between mature plant and morphologically undifferentiated cells of callous tissue was 1:1.7. A relationship between culture medium containing tyrosine and alkaloid production was also observed in the callous tissues of C. peruvianus. Since increased alkaloid production may be induced by additional factors such as tyrosine, increasing levels of tyrosine or other conditions of the culture medium may be considered factors for inducing higher alkaloid production by C. peruvianus callous tissues. Index Entries: Alkaloids; cactus; callous tissue culture; columnar cactus; mandacaru; tyrosine precursor. Introduction The ability to produce and store alkaloid substances is considered one of the most important characteristics of various cactus species (1–6). Similar to other cactacea, the Cereus peruvianus, known in Brazil as mandacaru, pro- duces alkaloid amines. Tyramine and hordenine are the main alkaloids in