**2. Methods**

#### **2.1 Extraction of bioactive compounds**

*Dioclea reflexa* seeds were obtained from the District of Jaman North in the Brong Ahafo region of Ghana (7° 57′1.8" North and 2° 41′52.08" West). The content of the seeds was dried in the sun, and the cotyledon ground into powder using a laboratory mortar and pestle. The drugs used for the study were obtained from a Company (Sigma-Aldrich, Saint Louis, MO, USA). 5 gram of *Dioclea reflexa* Seed powder was dissolved in 30 mL of 70% ethanol. 5 mL of the supernatant was used for immobilization using 10, 50, 75, 100, 150 and 200 mg of HNTs. 200 mg gave the best entrapment. The loaded HNTs were released with a buffer with pH ranging from 4 to 9 and the contents vacuum dried followed by dissolution in 1% dimethyl sulfoxide (DMSO) to give a final concentration of 3.2 mg/mL.

#### **2.2 Cell viability and electrochemical detection**

The methods used for preparing stock solution of the drug are previously described [23]. Cells were treated with the drugs or the extracts to study the effects at prescribe time interval followed by estimating cell death. A correlation of cell death to electrochemical behavior was conducted using cyclic voltammetry under steady-state conditions as previously described [17].
