The inhibition and eradication of oral biofilms is increasingly focused on the use of plant extracts as mouthwashes and toothpastes adjuvants. Here, we report on the chemical composition and the antibiofilm activity of 15 methanolic extracts of Iris species against both mono-(Pseudomonas aeruginosa, Staphylococcus aureus) and multi-species oral biofilms (Streptococcus gordonii, Veillonella parvula, Fusobacterium nucleatum subsp. nucleatum, and Actinomyces naeslundii). The phytochemical profiles of Iris pallida s.l., Iris versicolor L., Iris lactea Pall., Iris carthaliniae Fomin, and Iris germanica were determined by ultra-high performance liquid chromatography-high-resolution tandem mass spectroscopy (UHPLC-HRMS/MS) analysis, and a total of 180 compounds were identified among Iris species with (iso)flavonoid dominancy. I. pallida, I. versicolor, and I. germanica inhibited both the quorum sensing and adhesion during biofilm formation in a concentration-dependent manner. However, the extracts were less active against maturated biofilms. Of the five tested species, Iris pallida s.l. was the most effective at both inhibiting biofilm formation and disrupting existing biofilms, and the leaf extract exhibited the strongest inhibitory effect compared to the root and rhizome extracts. The cytotoxicity of the extracts was excluded in human fibroblasts. The inhibition of bacterial adhesion significantly correlated with myristic acid content, and quorum sensing inhibition correlated with the 7-β-hydroxystigmast-4-en-3-one content. These findings could be useful for establishing an effective tool for the control of oral biofilms and thus dental diseases.

Cannabidiol (CBD), together with its precursor cannabidiolic acid (CBDA), is the major phytocannabinoid occurring in most hemp cultivars. To ensure the safe use of these compounds, their effective isolation from hemp extract is required, with special emphasis on the elimination of ∆⁹-tetrahydrocannabinol (∆⁹-THC) and ∆⁹-tetrahydrocannabinolic acid (∆⁹-THCA-A). In this study, we demonstrate the applicability of fast centrifugal partition chromatography (FCPC) as a challenging format of counter-current preparative chromatography for the isolation of CBD and CBDA free of psychotropic compounds that may occur in Cannabis sativa L. plant extracts. Thirty-eight solvent mixtures were tested to identify a suitable two-phase system for this purpose. Based on the measured partition coefficients (K_D) and separation factors (α), the two-phase system consisting of n-heptane:ethyl acetate:ethanol:water (1.5:0.5:1.5:0.5; v:v:v:v) was selected as an optimal solvent mixture. Employing UHPLC-HRMS/MS for target analysis of collected fractions, the elution profiles of 17 most common phytocannabinoids were determined. Under experimental conditions, the purity of isolated CBD and CBDA was 98.9 and 95.1% (w/w), respectively. Neither of ∆⁹-THC nor of ∆⁹-THCA-A were present; only trace amounts of other biologically active compounds contained in hemp extract were detected by screening against in-house spectral library using UHPLC-HRMS. Graphical abstract

Cannabidiol (CBD), together with its precursor, cannabidiolic acid (CBDA), are major phytocannabinoids occurring in most hemp cultivars. To ensure safe use of these compounds, their effective isolation from hemp extract is required. Compounds free of ∆ 9 -tetrahydrocannabinol (∆ 9 -THC) and ∆ 9 -tetrahydrocannabinolic acid (∆ 9 -THCA) is a key criterion for ´purity´ assessment. In this study, we demonstrate the applicability of Centrifugal Partition Chromatography (FCPC) as a challenging format of counter-current preparative chromatography for complete removing of psychotropic phytocannabinoids from Cannabis sativa L. plant extracts. 38 solvent mixtures were tested to identify a suitable two-phase system for this purpose. Based on measured partition coefficients (K D ) and separation factors (α), heptane:ethyl-acetate:ethanol:water (1.5:0.5:1.5:0.5; v:v:v:v ) was selected as an optimal solvent mix. Employing U-HPLC-HRMS/MS for target analysis of collected fractions, the elution profiles of 17 most common phytocannabinoids were determined. Under experimental conditions when an entire elution zone was collected, CBD purity of 96.2 % was achieved, and CBDA purity was 89.7 %; compounds of the tetrahydrocannabinol group were not detectable. To learn more about ´impurities´ in CBD and CBDA fractions, targeted screening employing an in-house created spectral library of bioactive compounds was performed; altogether 121 co-eluting compounds were detected, although they were present in only trace amounts.