Determination of antibacterial activity of methanol extract of senna alata plant / Nur Hazwani Abdul Hamid

Senna alata L. is commonly used as antimicrobial remedy against skin infection on human such as eczema, scabies, tinea infection, shingles and even herpes. Crude methanol extract of leaves from Senna alata were tested in vitro against three bacteria which are Escherichia coli (E.coli), Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). This study was to determine antimicrobial susceptibility of crude methanol extract of Senna alata against E.coli, S. epidermidis and S. aureus in vitro and to identify the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) value of Senna alata methanol extract against E.coli, S. epidermidis and S. aureus in vitro. Disc diffusion method was used to determine the activity of selected bacteria against crude methanol extract of Senna alata. Minimal inhibitory concentration and minimal bactericidal concentration was used to identify lowest concentration that inhibit visible growth and killed most of the bacteria respectively. The highest zone of inhibition was observed against S. aureus (11.5mm) followed by S. epidermidis (11mm). However, the crude extract did not show any activity against E.coli. The value of MIC for S. aureus and S. epidermidis is 31.25 mg/ml. The value of MBC for both organisms S. aureus and S. epidermidis shows 500 mg/ml and 250 mg/ml respectively. This study showed that crude extract of Senna alata possessed antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis but not to E.coli. This finding provide new knowledge for treatment of common skin infection since the common bacterial skin infections are usually caused by Staphylococcus and Streptococcus species which is gram positive bacteria. However, further research about effect of Senna alata against wider range of bacteria and fungi and toxicological studies of the extract is recommended.