Antimicrobial activity of methanol extract from Etlingera punicea (Family: Zingiberaceae)

Antimicrobial activity referred to the potential of an element to kill or inhibit the spread of harmful microbes. The medical field utilised antimicrobial activity to develop medical treatments for a wide range of diseases caused by bacteria, viruses, fungi, and parasites. Etlingera punicea (Roxb.) R.M.Sm. (1986), was an herbaceous plant that originated from Southeast Asia, especially Sumatra, Indonesia. E. punicea was also native and cultivated in Malaysia and Thailand, frequently referred to as “Red Torch Ginger” or “Chalong”. The indigenous peoples traditionally used this plant for therapeutic purposes, especially for its effectiveness in curing stomach aches, fever, and headaches. The objective of the study was to ascertain the minimum inhibitory concentration of methanol extracts obtained from various components of E. punicea, such as leaves, pseudostems, and rhizomes, to evaluate their antimicrobial properties. Additionally, the study aimed to compare the inhibitory activity of these methanol extracts against specific microorganisms, including Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Several techniques were employed to determine the antimicrobial activity of the methanol extract. These procedures included the use of dilution series, subculturing bacteria, the continuous streaking technique, and the Kirby Bauer disc diffusion method. There were six distinct concentrations used which were 0 mg/ml, 2 mg/ml, 4 mg/ml, 6 mg/ml, 8 mg/ml, and 10 mg/ml. Next, streptomycin positive control antibiotic was utilised to compare and define the zone of inhibition. As a result, the highest inhibition zone was observed at a 10 mg/ml concentration of the leaf methanol extract of E. punicea against E. coli. This finding highlights the potential of E. punicea leaf extract as an effective antimicrobial agent. The methanol extract of E. punicea rhizome showed the lowest inhibition zone against E. coli at a concentration of 2 mg/ml, which indicates the Minimum inhibitory concentration (MIC). All concentrations of the three plant components of E. punicea, namely the pseudo stem, leaf, and rhizome, illustrated susceptibility to both microorganisms. The concentration of 10 mg/ml of EL extract exhibited the greatest inhibitory zone on E. coli, with 11.68 ± 1.386 mm. The lowest inhibitory zone was observed at a concentration of 2 mg/ml of E. coli of the ER, with an average of 6.300 ± 0.226 mm. Overall, the leaf extract of E. punicea highlighted the greatest amount of effective antibacterial action, resulting in the largest inhibition zone towards both microbes which were E. coli and S. aureus. This demonstrates that it has the potential to be used as a powerful antibacterial agent in future pharmaceutical studies.