Isolation of an antitubercular protein from Staphylococcus hominis IS2 from the custard apple and evaluation of its biosafety

Abstract

Tuberculosis (TB) is one of the leading causes of death throughout the world. Traditional medicine poses a serious challenge to drug resistance against Mycobacterium tuberculosis. Hence, it is an urgent need to develop, novel the anti-mycobacterial compounds. In this study, a potent anti-mycobacterial compound producing Staphylococcus hominis IS2 was isolated from the custard apple exhibiting novel anti-mycobacterial activity than other isolates. The bacterial strain was cultured and anti-mycobacterial compound was purified by the combination of ammonium sulphate precipitation and DEAE-cellulose column chromatography. The purified protein corresponding to 10 kDa presented anti-mycobacterial activity. It was further characterized and the difference in activity towards temperature and pH was observed (p < 0.01). The purified protein was analyzed using FT-IR and MALDI-TOF MS/MS analysis. Enzymatic treatment revealed the absence of carbohydrate moieties in the purified protein. The purified anti-mycobacterial protein presented anti-cancer activity against cervical cancer cell lines (HeLa) and was dose-dependent (p < 0.01). Haemolytic assay and Zebra fish embryo studies revealed that the isolated protein is safe at lower doses.