Antibacterial activity from Rhanterium adpressum flowers extracts, depending on seasonal variations

• Phenolic compounds of extracts collected in three different months from Rhanterium adpressum flowers have been studied.
• Extracts obtained from flowers collected in April contained the highest amount of polyphenols.
• Antimicrobial activity indicated remarkable antibacterial effect.

The main purpose of this study was to evaluate the effect of solvent extraction (acetone or methanol) on total phenolic content and antibacterial potential of Rhanterium adpressum flowers extracts. Flowers of the plant were harvested during three different months (April, May and June) for two years 2011 and 2012. The Folin–Ciocalteu method was used to determine the total phenolic content (TPC) in organic extracts; however, the antibacterial activity was tested using disc diffusion method. The highest phenolic content was detected in R. adpressum methanolic extracts collected in April. Same was evident in the antibacterial assay and it was also remarkable that the extracts activity was related to the concentration of phenolic compounds in active extracts, antibacterial activity was more efficient against Staphylococcus aureus and Salmonella typhi Gram + Bacteria. This is the first report on seasonal changes of phenolic compounds and antibacterial activity on R. adpressum and might be interesting to prospection of new molecules with antibacterial properties.