Plant origin products having anticancer properties come into prominence due to widespread of cancer. Plumbagin has various biological activities like anticancer activity. Estrogen receptor (ER) specificity of plumbagin (PL) and radiolabeled PL investigated by in vitro studies on ER+ and ER- adenocarcinoma cells. Additionally, PLGA encapsulation was carried out to reduce toxicity of plumbagin and encapsulation effect was investigated. Plumbagin radiolabeled with 100 % in yields and had ER specificity. Furthermore, PLGA encapsulation effected positively on properties of plumbagin; reduced toxicity, increased stability and ER specificity. A promising agent for the diagnosis of ER+ breast cancer is suggested.