Antibacterial Activity of Guava (Psidium guajava) Leaves and Safflower (Carthamus tinctorius) Seeds Extracts against Wound Infection Bacteria

Abstract

The aim of this study was to study the antibacterial activity of the different concentrations of n-hexene, methanol and aqueous extracts of the medicinal plants Psidium guajava leaves and Carthamus tinctorius seeds using agar dilution method. Hundred wound swabs were collected from patients with infected wounds who attended Khartoum Teaching Hospital during the period from April to June 2013. The n-hexene, methanol and aqueous extracts of Psidium guajava leaves (family Myrtaceae), and Carthamus tinctorius seeds (family Asteraceae) were screened for their antimicrobial activity against standard bacteria; one Gram positive (Staphylococcus aureus, ATCC 25923) and three Gram negative (Klebsiella pneumoniae ATCC 53657, Pseudomonas aeruginosa ATCC 27853 and E.coli ATCC 25922). These extracts were also screened against clinical isolates of S.aureus, K.pneumoniae, P.aeruginosa and E.col. Methanol extracts of Psidium guajava leaves and Carthamus tinctorius seeds were more active against one or more of the four bacteria ( S.aureus, E.coli, K.pneumoniae and P.aeruginosa). The aqueous extract of Psidium guajava leaves inhibits one or more of four tested bacteria. However the aqueous extract of Carthamus tinctorius seeds exhibited no activity against all tested bacteria and the n-hexene extract of two plants also showed no activity against all the tested bacteria. The antibacterial activity of five reference drugs; gentamicin, erythromycin, amoclan, ciprofloxacin and tetracycline were determined against the standard and clinical isolated bacteria and their activity was compared to the activity of plants' extracts. Gas chromatography analysis exhibited 23 compounds of Psidium guajava leaves and also these compounds are identified qualitatively by the Retention time, and quantitatively by the area under the curve.