Ultrasound-Assisted Extraction of Antimicrobial Compounds from Thymus daenensis and Silybum marianum and Investigation of its in Presence and Without of Natural Silver Nanoparticles

Abstract

The present study is devoted to construction of new antibacterial and anti-fungal agent based on combination of in situ synthesized silver nanoparticles with plants extract, while through a green synthesis Ag-NPs were synthesized at room temperature using Rosmarinus officinalis leaf extract. In this study, hydroalcoholic extracts have been used for with Ultrasonic method. Ultrasonication has recently received attention as a novel bioprocessing tool for process intensification in many areas of downstream processing. Antimicrobial activities of T. daenensis and S. marianum extracts in the presence and absence of Ag-NPs was investigated at concentrations between 12.5-50 mg/mL against Staphylococcus aureus (Gram-positive organisms), Escherichia coli (Gram-negative organisms), and fungal strains were Aspergillus oryzae, Candida albicans. Antimicrobial activity determined using agar disc diffusion method reveal that activities of Ag-NPs/T. daenensis were superior to Ag-NPs/S. marianum and extracts (T. daenensis and S. marianum). Medicinal plant extracts is able to synthesis the Ag-NPs as an eco-friendly and inexpensive method in large scale. The extract/Ag-NPs has good antibacterial and antifungal activity that candidate them as potential tool to combat against rapidly increasing antibiotic resistance. Antioxidant content of the extracts was also determined and demonstrated the highest antioxidant activities associated with the shoot of Thymusdaenensis (Total phenolic content: 198.71 ± 1.50 mg gallic acid equivalents/g of dried extract, DPPH: 48.80 ± 0.59 % inhibition and Total Flavonoid Content: 172.42 ± 1.43 mg rutin equivalents (RuE)/g of dried extract).