Evaluation of arjunolic acid against Brucella melitenis and in vitro cytotoxic study of lung adenocarcinomic cell line (A549)

Brucellosis, a neglected tropical disease of zoonotic nature, is caused by the genus Brucella, specifically by Brucella abortus and B. melitensis in cattle and humans, respectively. Arjunolic acid (AA) is a triterpenoid, isolated from Terminalia arjuna (Roxb.) Wight & Arn., a medicinally important plant, used to treat various diseases in the Indian system of medicine. Here, we tried to evaluate AA for its antibacterial activity against Brucella and the in vitro cytotoxicity assay on human lung adenocarcinomic alveolar basal epithelial cell line (A549). Also, we assessed the synergistic effect of arjunolic acid and aquatic extract of Tarenna asiatica (L.) Kuntze ex K.Schum. (syn. Chomelia asiatica) leaves against B. melitensis. AA displayed a considerable antibacterial activity [zone of inhibition (9 mm) with a minimum inhibitory concentration of 30 mu g/mL] against B. melitensis. The rate of cell death for the cancer cells was 82% at 100 mu g/ mL concentration of AA which indicates significant membrane disruption by AA in cancer cells. The estimated IC50 of AA against the A549 cell line was 139.90 mu g/mL. The highest synergistic activity was exhibited by combination of arjunolic acid and AqE of T. asiatica at the concentration of 1:1, respectively forming a zone of inhibition measuring 10 mm.