Phytochemical screening and antimicrobial activities of Gynura procumbens leaves extract against selected bacteria / Nur Syamimie Izzati Sazuki

Medicinal plants are the local heritage with global important and the world is endowed with a rich wealth of medicinal plants. Gynura procumbens or Sambung Nyawa is a tropical plants species from the Asteraceae family. This study was conducted to determine the phytochemical constituents, the antimicrobial activity and minimal inhibition concentration (MIC) of extract against selective Gram positive and Gram negative bacteria. The bacteria involved are Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa. Gentamicin was used as positive control while methanol and hexane were used as negative control. Four concentrations of extract which were 50 mg/ml, 100 mg/ml, 200 mg/mI, and 400 mg/ml were prepared for antimicrobial activity while 6.25 mg/ml, 12.5 mg/ml, 25 mg/ml and 50 mg/ml concentrations were prepared to determine the MIC. Result showed that alkaloid, flavonoid, tannin and saponin were present in methanol extract while tannin, saponin and terpenoids were present in hexane extracts. Only methanol extract of G. procumbens leaves showed antimicrobial activities against S. aureus, B. subtilis, K. pneumoniae and P. aeruginosa. However, negative results were shown for antimicrobial activities with hexane extract against all bacteria tested at all concentrations. Highest antimicrobial activities were recorded against S. aureus at 400 mg/mI concentrations with 10.5 mm of inhibition zone. Minimum inhibition concentration of methanol crude extract against S. aureus, B. subtilis, K. pneumoniae and P. aeruginosa were at 12.5 g/mL, 25 g/mL, and 50 mg/mL, respectively. G. procumbens leaves contain alkaloid, flavonoid, saponin, tannin and terpenoid. Methanol extract only shows antimicrobial activity. P. aeruginosa was more resistant among other bacteria.