MANAL M. ALKHULAIFI, KAHKASHAN PERVEEN NOUF M. AL-ENAZI, NOURA ALDOUSARY, RAGHAD ALZAHRANI AND KHAWLA ALSAMHARY
Abstract
Hibiscus plant having medicinal values proves to contain several bioactive chemicals however; the information pertaining to morphological alterations in bacterial cell due toextract of hibiscus flower are meagre. Therefore, in vitro antibacterial activity of hibiscus flower extracts prepared in Water (HW), ethanol (HE) and methanol (HM) were tested against ten human pathogenic bacteria by well diffusion assay. The HW showed maximum zone of inhibition (30.0 mm) against S. aureus and HM showed least zone of inhibition (8.3 mm) against E. coli. The most sensitive bacteria were S. aureus. MIC value of HW ranges from 0.78 to 6.25 mg/mL whereas for HE ranges from 1.56 to 25mg/mL. The bacterial cells of S. aureus, P. aeruginosa, E. coli and A. baumannii, untreated and treated with the sub-inhibitory concentration of the HW of were observed under Scanning electron microscope for the morphological changes. The SEM analysis clearly showed that the treated cells have several deformities, E. coli cells were rough, corrugated and pores were also observed whereas, A. baumannii treated cells were rough, lumpy and some cells were ruptured, similar deformities were also observed in the cells of S. aureus. Treated cells of P. aeruginosa were thin, deformed and shrunken. The observation shows that hibiscus flower extracts induce morphological changes in bacteria. Thus hibiscus can be a source of natural broad-spectrum antimicrobial agent.