Isolation and characterization of antioxidant and antibacterial compound from mango ginger (Curcuma amada Roxb.) rhizome.

The chloroform extract of mango ginger (Curcuma amada Roxb.) rhizome was subjected to antioxidant activity-guided purification by repeated silica gel column chromatography to obtain a pure antioxidant compound. The structure was deduced by analyzing UV, IR, liquid chromatography-mass spectrometry (LC-MS) and two-dimensional heteronuclear multiple quantum coherence transfer spectroscopy (2D-HMQCT) NMR spectral data, and named it as "Amadannulen", a novel compound. It exhibited DPPH radical scavenging activity, super oxide radical scavenging activity, lipid peroxidation inhibitory activity and metal chelating activity. Amadannulen also showed antibacterial activity against both Gram-positive and Gram-negative bacteria tested. It also exhibited bactericidal activity against M. luteus, B. cereus and B. subtilis.