To date, the natural alkaloids are mostly used in the field of pharmacological applications and the active substance of palmatine was extensively used in cancer therapy and other biomedical applications. Hence, in this study we report a simple preparation of poly-L-lysine (PLL) electro-polymerized on the surface of functionalized multiwalled carbon nanotubes (f-MWCNT) for electrochemical detection of palmatine content in human serum and urine samples. The active amino group of PLL plays a vital role towards the oxidation palmatine and exhibits superior electrocatalytic activity. Under optimum conditions, the prepared f-MWCNT/PLL composite shows a wide linear response range over the palmatine concentration ranging from 0.5 mu M to 425 mu M, and a detection limit (LOD) of 0.12 mu M based on S/N = 3 (signal to noise ratio). The real time monitoring of palmatine content in serum and urine samples displays an appropriate recoveries and excellent performance for the practical analysis. The advantage of this developed system was simple, higher electrocatalytic activity, long-term stability and low cost. We hope that the prepared composite opens a new way for the fabrication of different biosensors in the field of biomedical application. (C) 2017 Elsevier Inc. All rights reserved.