Effects of ethanolic extract of centella asiatica leaves on expression of thioredoxin reductase b in staphylococcus aureus (ATCC 25923) in vitro / Siti Athirah Zulkefli

Centella asiatica (C. asiatica) which are grows in Southest Asia countries posses antimicrobial activities against Staphylococcus aureus (S. aureus). The prevalence of multidrug-resistance strains of Staphylococcus aureus (MRSA) demands new discovery for treatment of its infections. The objective of this study are to study the antimicrobial activity of ethanolic extract of C. asiatica leaves against S. aureus (ATCC 25923) by determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanolic extract of C. asiatica against S. aureus, to determine the killing potential of ethanolic extract of C. asiatica against S. aureus in reference to hydrogen peroxide (H2O2) and to determine the expression of Thioredoxin reductase B (Trx B) in S. aureus in response to ethanolic extract of C. asiatica by SDS-PAGE. MIC of C. asiatica shown at 16 mg/ml while MBC is at 32 mg/ml. Liquid killing assay by C. asiatica of S. aureus at 30 minutes shown the percent of bacterial survive decreases compare with hydrogen peroxide with different 38%bacterial survival, while for C. asiatica extract with hydrogen peroxide have killing potential close with C. asiatica extract alone with different only 3 % bacterial survival (p>0.05). Thus C. asiatica have high potential to kill S. aureus compared with hydrogen peroxide. The effects of Trx B expression in S. aureus in response to C. asiatica have pipetting error when loading the sample into the wells. Thus, the expression of Trx B protein in S. aureus can’t be compared in this study between treated S. aureus and untreated S. aureus with C. asiatica extract. Further study needto be done in using HPLC, electroblotting and bioinformatics in identifying the amino acid sequences affected by treatment with extract.