Alleviation of Inhibitory Effects of Staphylococcus aureus on MPO Expression and Myeloperoxidase Activity in Human Neutrophils in vitro by Piper betle Linn. Ethanolic Extract

Abstract

A B S T R A C T Dissemination of S. aureus within the host is facilitated by its ability to survive neutrophils (PMNs) clearance mechanisms. Identifying agents from natural sources that can boost neutrophil killing ability is therefore beneficial. We investigated effects of P. betle ethanolic extract on Myeloperoxidase (MPO) and killing potential of PMNs. Staphylococcus aureus suppresses MPO expression in PMNs with corresponding loss of MPO activity and 19.23% protein reduction. Piper betle extract alleviated this repressor effect with threefold (3.106 mU mLG 1 µgG 1 protein) increase in specific MPO activity in 30 min and 13.44% increase in protein concentration PMNs treated with S. aureus together with extract increased activity even higher (3.629 mU mLG 1 µgG 1 protein) with a corresponding 19.23% increase in protein concentration. The RT-qPCR analyses confirmed that S. aureus down-regulates MPO causing reduced expression (0.053 fold), whereas, treating PMNs with S. aureus with extract increased MPO expression by 2.29 fold. Staphylococcus aureus showed 79.24% survival in PMNs, whereas, addition of extract enhanced neutrophil killing ability as reflected by a marked reduction in cell survival to 7.14%. Piper betle ethanolic extract overcomes the inhibitory effects of Staphylococcus aureus on myeloperoxidase, resulting in increased clearance of intracellular cells.