Comparative analysis of four different solvent extracts of Annona muricata bark based on bioactive compounds and antibacterial effectiveness

Traditional treatment of diseases has a great impact in every era due to the non-synthetic and various beneficial effects of medicinal plants. The miraculous medicinal plant <i>Annona muricata</i> L. (Magnoliales: Annonaceae) contains multiple pharmacologically active compounds. From the ethnic period, the plant has been used in the formulation of traditional medicines in the South-Asian region without knowing its actual therapeutic values. In this study, four different solvent extracts of the <i>A. muricata</i> bark were analyzed by GCMS, and their antibacterial efficacy was evaluated against multidrug-resistant (MDR) pathogenic bacteria. The GC-MS analysis detected the highest number of active compounds (thirty-two) in chloroform extract, while, n-hexane, ethanol, and ethyl acetate extract also contain seven, six, and three bioactive compounds respectively. The most prominent compounds present in the bark extracts having antibacterial activity are heneicosane, 13-docosenamide, hexadecane, hexadecanoic acid esters, benzyl benzoate,1,2-benzene dicarboxylic acid esters, 2,5-di-tert-butyl-1,4-benzoquinone (DTBBQ), eicosane, 9-octadecanamide etc. The <i>in vitro</i> antibacterial activity of the extracts was monitored against two Gram-positive and two Gram-negative multi-drug resistance (MDR) bacterial strains. The chloroform bark extract showed the lowest MIC values (75-120 μg/mL) and the highest inhibition against four bacteria (two Gram-positive and two Gram-negative), whereas, moderate activity was observed in other three extract. The presence of various bioactive compounds in the extracts certainly has potential therapeutic values and can prevent MDR pathogenic bacteria. Thus, the bark of <i>A. muricata</i> can be used as a potent natural antimicrobial agent and also reduce the chance of secondary infection caused by opportunistic pathogens.