Effects of extraction methods on antibacterial activity of centella asiatica leaves against pathogenic staphylococcus aureus and escherichia coli

Triterpene saponins are remarkable structural and bioactive glycosides in Centella asiatica (pegaga). Since extraction is an important step for separation of bioactive compounds from the plant material, this study was conducted to evaluate the antibacterial activity of C. asiatica leaves extract from different extraction methods, i.e. sonication, soxhlet, magnetic stirring and cold maceration. The efficacy of C. asiatica against Staphylococcus aureus and Escherichia coli by tube dilution and disc diffusion methods at three concentrations, i.e. 25, 50 and 100 mg/mL. Phytochemical screening of the plants showed the presence of alkaloid, tannin, steroid, glycosides and flavonoids. The plant extract with cold maceration method (MIC: 1.56 mg/mL) showed the highest antibacterial activity against S. aureus followed by sonication (MIC: 3.13 mg/mL), magnetic stirring (MIC: 3.13 mg/mL) and soxhlet extraction (MIC: 6.25 mg/mL). Similarly, cold maceration and magnetic stirring method (MIC: 1.56 mg/mL) exhibited the highest antibacterial activity against E. coli. Other extraction methods such as sonication and soxhlet also exhibited promising antibacterial activity against E. coli with MIC value of 3.13 mg/mL. Cold maceration extract had wider zones of inhibition (7.90–8.29 mm) and lowest MIC value (1.56 mg/mL) than other extraction methods. There is a significant difference (P < 0.05) between cold maceration and other extraction methods on the entire test organism, differences exist when compared individually at 100 mg/mL. This study revealed cold maceration method of extraction as the best method in antimicrobial susceptibility assay which could serve as stepping stone to develop C. asiatica as herbal medicine.