Properties of Salvia officinalis L. and Thymus serpyllum L. Extracts Free and Embedded into Mesopores of Silica and Titania Nanomaterials

Abstract

This study evidenced the nanoconfinement effect on polyphenolic extracts prepared from Salvia officinalis L. and Thymus serpyllum L. into the mesopores of silica and titania nanomaterials on their radical scavenging capacity and antimicrobial potential. The ethanolic and hydroalcoholic extracts obtained either by conventional or microwave-assisted extraction were characterized in terms of total polyphenols, total flavonoids, and chlorophyll content, as well as radical scavenging activity by consecrated spectrometric determinations. The phytochemical fingerprint of extracts was analyzed by high-performance liquid chromatography-photodiode array detector. Salvia officinalis extracts exhibited better radical scavenging capacity and antimicrobial potential than Thymus serpyllum extracts. The mesoporous MCM-41 silica and titania nanomaterials, prepared by the sol–gel method, were characterized by small- and wide-angle powder diffraction, FTIR spectroscopy, nitrogen adsorption–desorption isotherms, scanning electron microscopy and transmission electron microscopy, while the materials containing embedded extracts were analyzed through Fourier-transform infrared spectroscopy, N2 sorption measurements, and thermal analysis. All extracts free and embedded in mesoporous matrix exhibited high radical scavenger properties and good bactericidal activity against several reference strains. It was proved that by embedding the polyphenolic extracts into mesopores of silica or titania nanoparticles, the phytochemicals stability was enhanced as the materials containing extract exhibited higher radical scavenger activity after 3–6 months storage than that of the free extracts. Additionally, the extract-loaded material showed mild improved antimicrobial activity in comparison with the corresponding free extract.

Biological Evaluation of Black Chokeberry Extract Free and Embedded in Two Mesoporous Silica-Type Matrices

“…In another recent study performed by Brezoiu et al, a moderate improvement in antimicrobial activity was also observed for a polyphenolic extract of Salvia officinalis L. when embedded into the mesopores of a silica-type support compared to the free extract [19].…”

“…However, regarding the employment of MSNs for embedding polyphenolic extracts, there are only a few reports [ 17 , 18 , 19 ] in which it is mentioned that, through encapsulation, improved stability can be achieved in comparison to that of the extract alone, which is prone to a faster degradation. Evidence of the benefits of phytochemical encapsulation has also been found by using a bio-hybrid matrix consisting of Althaea officinalis L.…”

In Silico and In Vitro Evaluation of the Antimicrobial and Antioxidant Potential of Mentha × smithiana R. GRAHAM Essential Oil from Western Romania

“…In total, 1 µL culture from each test tube at MIC (with no visible growth) was inoculated using a loop (NuovaAptaca SRL, Canelli, Italy) on Columbia agar supplemented with 5% blood and maintained for 24 h at 37 °C for bacteria or on Sabouraud supplemented with chloramphenicol medium and maintained for 48 h at 28 °C for the yeast. The MBC/MFC was established as the lowest EO concentration, which killed 99.5% of the inoculated microorganisms [ 42 , 43 ]. All analyses were carried out in triplicate for each microbial strain.…”

Nanotechnologies: An Innovative Tool to Release Natural Extracts with Antimicrobial Properties

“…S. enterica, Shigella flexneri serotype 2b, Enterococcus faecalis, E. coli, Pseudomonas aeruginosa, S. aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Bacteroides fragilis, Candida albicans, Candida parapsilosis Antimicrobial activity [193] MCM-41 was also synthesized by the sol-gel method assisted by hydrothermal treatment and employing tetraethyl orthosilicate and n-cetyl-n,n,n-trimethyl ammonium bromide as silica source and template, respectively. Polyphenolic extracts of Salvia officinalis L. and Thymus serpyllum L. were encapsulated in these matrices and tested against S. enterica, S. flexneri serotype 2b, E. faecalis, E. coli, P. aeruginosa, S. aureus, S. pneumoniae, S. pyogenes, B. fragilis, C. albicans, and C.n parapsilosis, although showing milder improved antibacterial properties with respect to the parent extracts [193].…”