Simultaneous analysis of water-soluble and fat-soluble vitamins through RP-HPLC/DAD in food supplements and brewer’s yeast

The current study is focused on investigation and quantitation of seven commercially available on the Bulgarian market food supplements, containing multivitamin mixtures of water-soluble and fat-soluble vitamins. In addition, a second fermentation brewer’s yeast is also analyzed. The analytical procedures are performed on a RP-HPLC/DAD using Purospher STAR C18 (Merck Millipore, Germany) 5 μm, 25 × 0.46 cm column, conditioned at 25 °C in a column oven. Dionex UltiMate 3000 high performance liquid chromatograph was carried out in diode array detector, set up at 270 nm for water-soluble vitamins, except for vitamin B5, where 210 nm was applied as analytical wavelength. The fat-soluble vitamins were detected at 325 nm and 265 nm for vitamin A and vitamin E, respectively. Two general methods were developed where Method 1 was based on gradient elution and Method 2 was based on isocratic elution. Both methods identified stated by the manufacturer labeled amounts. The developed methods are applicable for routine analysis of vitamin contents both in multivitamin preparations and in brewer’s yeast from secondary fermentation

Structural, Thermal, and Storage Stability of Rapana Thomasiana Hemocyanin in the Presence of Cholinium-Amino Acid-Based Ionic Liquids

Novel biocompatible compounds that stabilize proteins in solution are in demand for biomedical and/or biotechnological applications. Here, we evaluated the effect of six ionic liquids, containing mono- or dicholinium [Chol]1or2 cation and anions of charged amino acids such as lysine [Lys], arginine [Arg], aspartic acid [Asp], or glutamic acid [Glu], on the structure, thermal, and storage stability of the Rapana thomasiana hemocyanin (RtH). RtH is a protein with huge biomedicinal potential due to its therapeutic, drug carrier, and adjuvant properties. Overall, the ionic liquids (ILs) induce changes in the secondary structure of RtH. However, the structure near the Cu-active site seems unaltered and the oxygen-binding capacity of the protein is preserved. The ILs showed weak antibacterial activity when tested against three Gram-negative and three Gram-positive bacterial strains. On the contrary, [Chol][Arg] and [Chol][Lys] exhibited high anti-biofilm activity against E. coli 25213 and S. aureus 29213 strains. In addition, the two ILs were able to protect RtH from chemical and microbiological degradation. Maintained or enhanced thermal stability of RtH was observed in the presence of all ILs tested, except for RtH-[Chol]2[Glu]

Pistacia lentiscus by-product as a promising source of phenolic compounds and carotenoids: Purification, biological potential and binding properties

The hydro-distilled leaves of Pistacia lentiscus are considered as an agricultural residue and of no commercial value yet. In this study, chromatographic purification of a methanolic fraction of P. lentiscus L. (lentisk) distilled leaves yielded pure compounds, including Quercitrin (QUE) and Loliolid (LOL) which are characterized, for the first time, in the lentisk leaves’ residue. The inhibitory potential of QUE and LOL was investigated against tyrosinase and acetylcholinesterase activities using enzymatic assays and lysozyme fibrillation through Thioflavin-T fluorescence assay. Their binding mode to Bovine Serum Albumin (BSA) was also assessed by several spectroscopic analyses. Results show that QUE was more potent to inhibit enzyme activity than LOL. Besides, the Thioflavin-T assay confirmed that only QUE was able to block the fibril formation at a concentration of 25 μg/mL. Furthermore, the BSA quenching mechanism by QUE and LOL is a static process with conformational changes in BSA. Interestingly, our findings may provide novel insights into the potentiality of lentisk to be used as a bioresource for the generation of Quercitrin and Loliolid which can be commercially exploited in the field of cosmeceuticals and nutraceuticals

Ketoprofen-Based Ionic Liquids: Synthesis and Interactions with Bovine Serum Albumin

The development of ionic liquids based on active pharmaceutical ingredients (API-ILs) is a possible solution to some of the problems of solid and/or hydrophobic drugs such as low solubility and bioavailability, polymorphism and an alternative route of administration could be suggested as compared to the classical drug. Here, we report for the first time the synthesis and detailed characterization of a series of ILs containing a cation amino acid esters and anion ketoprofen (KETO-ILs). The affinity and the binding mode of the KETO-ILs to bovine serum albumin (BSA) were assessed using fluorescence spectroscopy. All compounds bind in a distance not longer than 6.14 nm to the BSA fluorophores. The estimated binding constants (KA) are in order of 105 L mol−1, which is indicative of strong drug or IL-BSA interactions. With respect to the ketoprofen-BSA system, a stronger affinity of the ILs containing l-LeuOEt, l-ValOBu, and l-ValOEt cation towards BSA is clearly seen. Fourier transformed infrared spectroscopy experiments have shown that all studied compounds induced a rearrangement of the protein molecule upon binding, which is consistent with the suggested static mechanism of BSA fluorescence quenching and formation of complexes between BSA and the drugs. All tested compounds were safe for macrophages

Salicylic Acid as Ionic Liquid Formulation May Have Enhanced Potency to Treat Some Chronic Skin Diseases

In recent years, numerous studies have shown that conversion of conventional drugs in ionic liquid (IL) formulation could be a successful strategy to improve their physicochemical properties or suggest a new route of administration. We report the synthesis and detailed characterization of eight salicylic acid-based ILs (SA-ILs) containing cation non-polar or aromatic amino acid esters. Using in vitro assays, we preliminary evaluated the therapeutic potency of the novel SA-ILs. We observed that conversion of the SA into ionic liquids led to a decrease in its cytotoxicity toward NIH/3T3 murine embryo fibroblasts and human HaCaT keratinocytes. It should be mentioned is that all amino acid alkyl ester salicylates [AAOR][SA] inhibit the production of the proinflammatory cytokine IL-6 in LPS-stimulated keratinocytes. Moreover, keratinocytes, pretreated with [PheOMe][SA] and [PheOPr][SA] seem to be protected from LPS-induced inflammation. Finally, the novel compounds exhibit a similar binding affinity to bovine serum albumin (BSA) as the parent SA, suggesting a similar pharmacokinetic profile. These preliminary results indicate that SA-ILs, especially those with [PheOMe], [PheOPr], and [ValOiPr] cation, have the potential to be further investigated as novel topical agents for chronic skin diseases such as psoriasis and acne vulgaris