Abstract

Andrographolide is a labdane diterpenoid isolated from Andrographis paniculata. The plant extract and andrographolide has long been used in traditional medicine practices mainly for gastrointestinal diseases and improving liver function. Andrographolide has shown various pharmacological properties including anti-inflammatory, antioxidant and anticancer activity. This study evaluated the effect of andrographolide on proliferation of human gastric carcinoma cells in relevance to p53 and Mdm-2 pathways. Andrographolide inhibited the proliferation of SGC7901 and AGS cells in a dose-dependent manner with estimated IC₅₀ values 38 and 44 μM respectively. Effect of andrographolide on p53 activity was ascertained by using a p53 activator (RITA) which showed synergistic inhibition of cell proliferation. While andrographolide when used in combination with a p53 inhibitor (pifithrin-α) showed potent restriction over its response. Andrographolide caused decrease in mitochondrial membrane potential as an indicator of apoptotic activity. Andrographolide activated the expression of p53 protein and gene and downregulated the levels of Mdm-2 (negative regulator of p53). Andrographolide inhibited the colony formation abilities in SGC7901 in a p53-dependent manner followed by induction of mitochondrial intrinsic apoptosis through activation of caspases-9 and -3, cleavage of PARP, and inhibition of pro-apoptotic Bcl-2. Andrographolide induced p53 mediated apoptosis in gastric carcinoma cells which adds to a novel approach in anticancer therapies.