Antibacterial activity by Dombeya wallichii plant extracts obtained by ultrasound-assisted extraction

The global health community is concerned about the establishment and spread of antibiotic resistance as well as the evolution of new strains of disease-causing bacteria. The creation of alternatives to antibiotics is required for effective treatment. Medicinal plants could be a good source of medication to combat this problem. Dombeya wallichii, which is commonly called Pink Ball Tree in the family Sterculiaceae, has been documented to have medicinal potential. This species of Dombeya has been studied for a wide range of medicinal properties, including antimicrobial activity. Considering their vast potential, we hypothesized that the extracts of D. wallichii would have broad-spectrum antibacterial properties. We also hypothesized that ultrasonic-assisted extraction could also improve the separation and extraction of these medicinal compounds. Here, we screened the antibacterial potential of bark, flower, stem, and leaf extracts against five strains of food spoilage-causing bacteria. Our results indicated that the extraction yield was effectively increased by employing the ultrasonic-assisted approach. We observed the highest antibacterial activity in the stem extracts, followed by leaf and bark extracts. The extracts were more effective against tested Gram-positive bacteria when compared with Gram-negative strains. Hence, these extracts had a narrow spectrum of antibacterial activity and were comparatively less potent than most of the broad-spectrum antibiotics. Further research for potential therapeutic applications should be done in order to better understand the antibacterial activity of D. wallichii. This knowledge may help design future antimicrobial compounds.