Antimicrobial activity of Parrotiopsis jacquemontiana and Caesalpinia decapetala plant extracts against selected pathogens

Abstract

Antimicrobial-resistant bacteria are a global health concern. Some gram-negative bacteria have acquired resistance to many notorious diseases induced by various pathogens. Therefore, new antibacterial agents are needed to combat these infections. We utilised the agar well diffusion method to find the antibacterial capabilities of Caesalpinia decapetala and Parrotiopsis jacquemontiana aqueous and methanolic extracts. We aimed to find the efficacy of these extracts and their various components against selected pathogens. Methanolic extract showed significantly higher antimicrobial activity against all tested pathogens compared to aqueous extracts, such as 20 mg/mL of MRE-CD, which showed 12.16 ± 1.04 mm inhibitions against P. aeruginosa. In contrast, 10.5± 0.5 mm against S. dysenteriae inhibition compared to 20 mg/mL of MRE-PJ showed 10.16±0.76 mm inhibition against E. coli. Meanwhile, only aqueous root extracts of P. jacquemontiana at 10 mg/mL showed the least 1.5 ± 1.32 against S. dysenteriae mm inhibitions, while E. coli appears to be the less sensitive strain at 10 mg/mL of methanolic stem extract of P. jacquemontiana compared to the aqueous extract of C. decapetala stems, significantly affecting the growth of gram-negative bacterial strains. Therefore, these plant extracts have great natural antimicrobials, and further evaluation would be necessary to use them.