Effects of Andrographis paniculata (hempedu bumi) methanolic leaves extract on superoxide dismutases (sodA & sodM) expression in staphylococcus aureus (ATCC 25923) in vitro / Anis Haziqah Ayop

Andrographis paniculata (A. paniculata) or “Hempedu Bumi” is known for its antimicrobial properties and is widely used as traditional medicine worldwide. The main objective of this study is to determine the antimicrobial effects of Andrographis paniculata methanolic leaves extract against S. aureus (ATCC 25923) by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), killing potential and the expression of superoxide dismutase (SodA and SodM) enzymes in Staphylococcus aureus after treatment with MIC of Andrographis paniculata methanolic leaves extract. Serial dilutions of the Andrographis paniculata methanolic leaves extract were performed to determine the lowest concentration that inhibited growth of S. aureus and followed by determination of MBC. Time-kill assay was done in reference of 10mM methyl viologen (paraquat) to determine the effectiveness of killing of S. aureus by Andrographis paniculata methanolic leaves extract. SDS-PAGE analysis was used to determine the expression of superoxide dismutase (SodA and SodM) enzymes in S. aureus after treatment with MIC of the extract compared to the untreated S. aureus. The A. paniculata methanolic extract showed antimicrobial effects against S. aureus as MIC and MBC of 50mg/ml and 100mg/ml respectively. It also enhanced killing potential of S. aureus in the presence of 10mM methyl viologen where only 24.07% bacteria survive. However, the extract did not affect the expression of superoxide dismutases (Sod) in S. aureus, therefore it does not induce oxidative stress compared with sample treated with 32μg penicillin thus other enzymes should be tested.