Interaction with bovine serum albumin of an anti-oxidative pectic arabinogalactan from Andrographis paniculata.

•A highly branched pectic arabinogalactan could be isolated by traditional water extraction method.•The anti-oxidative properties of this polymer are comparable with standard anti-oxidants.•The phenolic acid moieties are the probable functional sites.•Formation of a water soluble complex between this polymer and bovine serum albumin was established.