Two thiophenes; 5-(3-buten-1-ynyl)-2,2'-bithiophene (2) and α-tertthienyl (9), two alkaloids; echinopsine (10) and echinorine (11), three flavonoids; genkwanin (5), apigenin (6), and rutin (7), two triterpenoids; lupeol acetate (1) and lupeol linoleate (4), together with 2,6,10-trimethyldodeca-2,6,10-triene (4) and β-sitosterol glucoside (8) were isolated from the aerial parts of Echinops albicaulis. Antioxidant, antimicrobial and antiprotozoal activities were evaluated. E. albicaulis aqueous methanolic extract (50, 10, and 1 mg/mL) showed significant antioxidant activity comparable to the potent antioxidant, N-acetyl cysteine, moreover, the aqueous methanolic extract (1 mg/mL) significantly reduced intracellular reactive oxygen species in active cell cultures of human peripheral blood mononuclear cells under oxidative stress more than the reference antioxidant N-acetyl cysteine. None of the isolated compounds showed antimicrobial or antiprotozoal activities at concentration up to 20 μg/mL.
Onosma roots are widely used in traditional medicine to treat various diseases throughout the world. In this study, for the first time, we investigated the component composition and biological activity of various extracts from the roots of Onosma gmelinii collected in the highlands of the Kakpakty Mountains of the Almaty region (Republic of Kazakhstan). Extracts were obtained by three different methods: percolation extraction, ultrasound-assisted extraction, and supercritical carbon dioxide extraction. The component composition of the extracts was determined by gas chromatography/mass spectrometry (GC/MS), naphthoquinones by thin-layer chromatography (TLC), and spectrophotometric method. In this study, the presence of shikonin and its derivatives in the extracts was confirmed. The concentration of naphthoquinones during CO2 extraction was about 40%, during ultrasonic extraction about 3%, and during percolation extraction about 1.3%. The GC-MS method identified 69 chemical compounds in the ultrasonic extract, 46 compounds in the CO2 extract, and 51 compounds in the percolation extract. The extracts were tested on a panel of bacteria and viruses: two Gram-negative bacteria (Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027); nine Gram-positive bacteria (Staphylococcus aureus ATCC 6538-P, Staphylococcus aureus ATCC BAA-39, Staphylococcus epidermidis ATCC 51625, Staphylococcus epidermidis ATCC 12228, Streptococcus pyogenes ATCC 19615, Streptococcus pneumoniae ATCC BAA-660, Enterococcus hirae ATCC 10541, Enterococcus faecalis ATCC 51575, Enterococcus faecium ATCC 700221); and two fungal species (Candida albicans ATCC 10231, Candida albicans ATCC 2091); five subtypes of influenza virus A (A/FPV/Weybridge/78 (H7N7), A/Swine/Iowa/15/30 (H1N1), A/black-headed gull/Atyrau/743/04 (H13N6), A/FPV/Rostock/1934 (H7N1), A/Almaty/8/98 (H3N2)). The root extracts of Onosma gmelinii showed antibacterial activity in different degrees against all tested Gram-positive bacterial strains, while no inhibitory effect on Gram-negative bacteria was observed. The results indicated that the ultrasonic extract effectively inhibits the growth of the majority of tested Gram-positive bacteria (MBC from 18.3 to 293.0 µg/mL). CO2 extract had the greatest bactericidal activity (MBC from 0.1 to 24.4 µg/mL). Percolation extract insignificantly inhibited bacterial growth (MBC from 2343.8 to 4687.5 µg/mL). CO2 extract and ultrasonic extract significantly reduced the activity of C. albicans. The results of the antiviral action showed that the ultrasonic extract has the greatest effectiveness against different subtypes of the influenza virus A, while other extracts did not show significant activity.
The freeze-thaw (F/T) method is commonly employed during the processing and handling of drug substances to enhance their chemical and physical stability and obtain pharmaceutical applications such as hydrogels, emulsions, and nanosystems (e.g., supramolecular complexes of cyclodextrins and liposomes). Using F/T in manufacturing hydrogels successfully prevents the need for toxic cross-linking agents; moreover, their use promotes a concentrated product and better stability in emulsions. However, the use of F/T in these applications is limited by their characteristics (e.g., porosity, flexibility, swelling capacity, drug loading, and drug release capacity), which depend on the optimization of process conditions and the kind and ratio of polymers, temperature, time, and the number of cycles that involve high physical stress that could change properties associated to quality attributes. Therefore, is necessary the optimization of F/T conditions and variables. The current research regarding F/T is focused on enhancing the formulations, the process, and the use of this method in pharmaceutical, clinical, and biological areas. The present review aims to discuss different studies related to the impact and effects of the F/T process on the physical, mechanical, and chemical properties (porosity, swelling capacity) of diverse pharmaceutical applications with an emphasis on their formulation properties, the method and variables used, as well as challenges and opportunities in developing. Finally, we review the experimental approach for choosing the standard variables studied in the F/T method applying the systematic methodology of quality by design.
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