Andrographolide is a labdane diterpenoid that is the main bioactive component of the medicinal plant Andrographis paniculata. Andrographolide is an extremely bitter substance extracted from the stem and leaves of A. paniculata. The present studies revealed that andrographolide also possesses potent antioxidant properties which is evident from its capacity to scavenge hydroxyl radical, superoxide anion radical, hydrogen peroxide and DPPH radical in chemically defined system, in vitro. Moreover, andrographolide was found to provide protection against Cu-ascorbate induced elevation in the levels of lipid peroxidation and protein carbonylation as well as reduction in the levels of GSH in goat cardiac mitochondria incubated in vitro. This compound was further found to protect against Cu-ascorbate induced alterations in the activities of Mn-SOD, glutathione reductase and the activities of some of the Kreb’s cycle enzymes. Andrographolide was also found to protect against Cu-ascorbate induced mitochondrial swelling, mitochondrial membrane cardiolipin content, di-tyrosine level as well as mitochondrial DNA damage. The results of this study suggest that andrographolide may be considered as a future therapeutic antioxidant and may be used singly or as a co-therapeutic in the treatment of diseases associated with mitochondrial oxidative stress. © 2014, Global Research Online. All rights reserved.