Andrographolide: A natural product template for the generation of structurally and biologically diverse diterpenes

From times immemorial, natural products have played an important role in the management of human health. Andrographis paniculata, belonging to the family Acanthaceae and its constituents are reported to possess a wide range of biological properties such as anti-cancer, anti-diabetic, anti-inflammatory, anti-bacterial, anti-malarial, anti-hepatitis, anti-HIV, anti-atherosclerosis, hepatoprotective, FXR antagonist, and α-glucosidase inhibition. Andrographolide (1), is identified as the major bioactive constituent of the plant. Promising biological properties of the major constituent Andrographolide (1) along with structural amenability for facile semi-synthetic modifications have led to the generation of structurally diverse bioactive labdane diterpenes by several research groups. The promising biological activities exhibited by these semi-synthetic derivatives have further kindled interest and the continued research is evidenced through publications, patents and could possibly lead to the development of Andrographolide based medicines in future. The present review aims at compiling and discussing various semi-synthetic derivatives of Andrographolide in relation to their biological properties and their mechanisms of action.