Nanoliposome-encapsulated and biopolymer-coated phlorotannin extract of Sargassum tenerrimum: A promising approach for enhanced antibacterial activity against acne-related bacteria

Recently, the use of nanoliposome and coated systems has received much attention due to their unique properties for more effective delivery of antibacterial agents. The phenolic extract was co-encapsulated into nanoliposomes and a polyelectrolyte delivery system was obtained by the sequential deposition of positive chitosan (CH) and negative sodium alginate (AL) onto the surface of anionic nanoliposomes (NLs). Phlorotannin compounds were identified by HPLC and the properties of nanoliposomes were evaluated. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of NLs/extracts against acne-related bacteria were determined. The identified compounds of the extract were phloroglucinol, bieckol, dieckol, phlorofucofuroeckol A, and eckol. The mean particle size, zeta potential, and polydispersity index of NLs were 19.77 nm, -13.3 mV, and 0.212, respectively. NLs efficiency on days 0 and 60, at 4°C, was 91.22 and 67.16%, respectively. Release of NLs at pH 3 was higher than at pH 5 and 7. The MIC and MBC values of NLs, AL-CH-NLs, and CH-NLs against all studied bacteria are lower than the extracts. The MIC and MBC activity of the nanoliposomes and coated nanoliposomes decreased over time. The results suggested that NLs, especially CH-NLs and AL-CH-NLs, can be considered an effective carrier system for phenolic compounds.