Utilizing geothermal botanical resources: Evaluating antiplanktonic and biofilm inhibitory effects of Jaboi area plant extracts

Context: Biofilm formation exacerbates infections and stimulates antimicrobial resistance, prompting a search for potent antimicrobial agents from diverse sources. Plants in unique environments, such as geothermal areas, offer prospective medicinal benefits due to their resilience against pathogens. Aims: To investigate the antiplanktonic and antibiofilm activities of five selected endemic plants from the geothermal area in Sabang comprising Hydnophytum formicarum Jack (Rubiaceae), Syzigium myrtifolium Walp (Myrtaceae), Aporosa octandra (Buch.-Ham. ex D.Don) Vickery (Phyllanthaceae), Memecylon coeruleum Jack (Melastomaceae) and Memecylon edule Roxb (Melastomaceae). Methods: The ethanol extracts were prepared using the maceration method. The identification of phytochemicals was carried out using TLC with specific spraying reagents. The volatile compounds were identified using GC-MS. The evaluation of antiplanktonic and antibiofilm activities was conducted by using the microdilution method against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853. Results: H. formicarum and M. edule extracts demonstrated the highest antiplanktonic activity against both bacteria. M. edule showed superior ability to prevent biofilm formation in S. aureus, while A. octandra exhibited the highest antibiofilm activity against P. aeruginosa. M. edule showed relatively potent antiplanktonic and antibiofilm activity. The GC-MS analysis revealed the presence of bioactive compounds from saturated and unsaturated fatty acids, phenols, terpenes, furan compounds, and sugars. Conclusions: M. edule from geothermal areas demonstrated potent antimicrobial activity against S. aureus biofilms and P. aeruginosa, indicating its potential against biofilm-related infections and antimicrobial resistance.