Basil (Ocimum basilicum L.) has a long traditional use as spice in both folk and conventional medicine. Basil extracts (BEs) as well as essential oil (EO) represents a rich source of phytochemicals, many of which possess diverse biological activities. The objectives of this study were to assess antioxidant and antibacterial activities of BEs and EO, obtained from plants cultivated in Republic of Serbia. EO was isolated by hydrodistillation, while BEs were obtained by Soxhlet extraction and ultrasound-assisted maceration, using 70% and 96% ethanol. In prepared BEs total phenolic (TPC) and total flavonoid content (TFC) were determined spectrophotometrically. Antioxidant activity was evaluated by DPPH and FRAP assays. A higher TPC was obtained using 70% ethanol, while 96% ethanol proved to be more effective for the extraction of flavonoids. In both antioxidant assays, BEs showed remarkable antioxidant properties compared to EO. Also, regardless the extraction method and assay applied, the 70% ethanol extracts proved to be more potent than 96% ethanol ones. Both antioxidant assays strongly correlated with TPC than with TFC. For antibacterial activity assay, minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) were obtained by the microdilution method. Tested Gram-negative bacteria (E. coli and S. Typhimurium) were more resistant than Gram-positive (S. aureus and L. monocytogenes). Opposite to results of antioxidant activity, EO expressed superior antibacterial activity. Based on the obtained results, it can be concluded that basil represents powerful source of biologically active components which can express strong antioxidant and antibacterial activity.
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The percentage of ethanol are here a Kay
Thank you for your question.
The difference in the extraction efficiency of these active components is due to their polarity.
Higher efficiency of the 70% ethanol compared to the 96% confirms the literature data that in binary systems, such as the mixture of ethanol and water, one solvent can increase the solubility of phenolic compounds while the other can increase the desorption. Therefore, these mixtures are the most suitable for more complete extraction of phenolic compounds.
Also, the literature reports that the flavonoids of plant species of the Lamiaceae family are nonpolar, were confirmed in this work whereas 96% ethanol had higher yield.