Microalgae are known to be rich in protein. In this study, we aim to investigate methods of producing and purifying proteins of 98 microalgae including Chlorella vulgaris, Arthrospira platensis, Nostoc sp., Dunaliella salina, and Pleurochrysis carterae (Baltic Sea). Therefore, we studied their amino acid composition and developed a two-stage protein concentrate purification method from the microalgae biomass. After an additional stage of purification, the mass fraction of protein substances with a molecular weight greater than 50 kDa in the protein concentrate isolated from the biomass of the microalga Dunaliella salina increased by 2.58 times as compared with the mass fraction before filtration. In the protein concentrate isolated from the biomass of the microalga Pleurochrysis cartera, the relative content of the fraction with a molecular weight greater than 50.0 kDa reached 82.4%, which was 2.43 times higher than the relative content of the same fractions in the protein concentrate isolated from this culture before the two-stage purification. The possibilities of large-scale industrial production of microalgae biomass and an expanded range of uses determine the need to search for highly productive protein strains of microalgae and to optimize the conditions for isolating amino acids from them.

Microalgae are rich in nutrients and biologically active substances such as proteins, carbohydrates, lipids, vitamins, pigments, phycobiliproteins, among others. The lipid composition of the microalgae Chlorella vulgaris, Arthrospira platensis, and Dunaliella salina was screened for the first time. The proposed method for purifying the lipid complex isolated from microalgae’s biomass involved dissolving the lipid-pigment complex in n-hexane for 4 h and stirring at 500 rpm. We found that the largest number of neutral lipids is contained in the biomass of microalgae Arthrospira platensis, fatty acids, polar lipids (glycerophospholipids), and unsaponifiable substances—in the biomass of microalgae Dunaliella salina, chlorophyll, and other impurities—in the biomass of microalgae Chlorella vulgaris. The developed method of purification of the fatty acid composition of the microalgae lipid complex confirmed the content of fatty acids in microalgae, which are of interest for practical use in the production of biologically active components. We also determined the potential of its use in the development of affordable technology for processing microalgae into valuable food and feed additives.

Osteoarthritis (OA) is a degenerative joint disease and an important cause of incapacitation. There is a lack of drugs and effective treatments that stop or slow the OA progression. Modern pharmacological treatments, such as analgesics, have analgesic effects but do not affect the course of OA. Long-term use of these drugs can lead to serious side effects. Given the OA nature, it is likely that lifelong treatment will be required to stop or slow its progression. Therefore, there is an urgent need for disease-modifying OA treatments that are also safe for clinical use over long periods. Phytonutraceuticals are herbal products that provide a therapeutic effect, including disease prevention, which not only have favorable safety characteristics but may have an alleviating effect on the OA and its symptoms. An estimated 47% of OA patients use alternative drugs, including phytonutraceuticals. The review studies the efficacy and action mechanism of widely used phytonutraceuticals, analyzes the available experimental and clinical data on the effect of some phytonutraceuticals (phytoflavonoids, polyphenols, and bioflavonoids) on OA, and examines the known molecular effect and the possibility of their use for chondroprotection.

Tanacetum vulgare is an herbaceous plant widely used in folk medicine. It is rich in phenolic acids and flavonoids, which have pharmacological and medicinal properties, such as anthelmintic, antispasmodic, tonic, antidiabetic, diuretic, and antihypertensive. This study aimed to confirm the presence of biologically active substances in Tanacetum vulgare and to determine the pharmacological spectrum of biological activity of Tanacetum vulgare extract components. When preparing Tanacetum vulgare extracts, the highest yield was observed when using the maceration method with a mixture of solvents methanol + trifluoroacetic acid (22.65 ± 0.68%). The biologically active substances in Tanacetum vulgare extract samples were determined using high-performance liquid chromatography. Biologically active substances such as luteolin-7-glucoside (550.80 mg/kg), chlorogenic acid (5945.40 mg/kg), and rosmarinic acid (661.31 mg/kg) were identified. Their structures were determined. The experiments have confirmed the antioxidant and antibacterial activities. Secondary metabolites of Tanacetum vulgare extracts have been found to have previously unknown biological activity types; experimental confirmation of their existence will advance phytochemical research and lead to the development of new drugs.

Glycyrrhiza glabra or licorice has long been known as a commonly used Ayurvedic herb. This study aims to investigate the effect of extraction methods on the chemical composition and biologically active properties of Glycyrrhiza glabra extract samples. The highest yield of the Glycyrrhiza glabra extract (21.31 ± 0.64 wt.%) was produced using the Soxhlet extraction method with methanol. The highest concentrations of biologically active substances (3,4-dihydroxybenzoic acid, n-coumaric acid, luteolin-7-glucoside, acacetin, apigenin-7-O-glucoside, chicoric acid, and hesperetin) were found in these samples of Glycyrrhiza glabra extracts. When applying the maceration method using a mixture of solvents methanol-NaOH, rosmarinic acid was identified, and catechin was found in large quantities with a mixture of methanol-trifluoroacetic acid (TFA). Growth inhibition zones were determined for Escherichia coli (13.6 ± 0.41 mm), Pseudomonas aeruginosa (10.8 ± 0.32 mm), Bacillus subtilis (16.1 ± 0.48 mm), and Candida albicans (13.2 ± 0.39 mm) when exposed to samples of Glycyrrhiza glabra extracts obtained by the Soxhlet method with methanol. The antioxidant activity of Glycyrrhiza glabra extract samples obtained by the Soxhlet method was 117.62 ± 7.91 µmol Trolox equivalent/g, using the ABTS method (highest value), and 23.91 ± 1.12 µmol Trolox equivalent/g according to the FRAP method (smallest). The antioxidant activity of the extract samples according to the DPPH method was an intermediate value of 58.16 ± 3.90 µmol Trolox equivalent/g. Antibacterial and antioxidant activities are manifested by the polyphenolic compounds and flavonoids contained in the samples of the methanol extract of Glycyrrhiza glabra produced using the Soxhlet method. These Glycyrrhiza glabra extract samples have the potential to become a natural alternative to existing therapies for the elimination of bacterial infections or the prevention of premature aging caused by free radicals and oxidative stress in the human body.

Microalgae are widely used to produce sorbitol, ethyl and methyl alcohols, acetone, organic acids, esters, pigments, chlorophylls, carotenoids, and other compounds. The purpose of this work was to study the potential of the Baltic Sea microalgae Arthrospira platensis and Chlorella vulgaris, as new ingredients for functional bread. Bread was baked with a dry mixture of Arthrospira platensis and Chlorella vulgaris microalgae (1:1). Gas chromatography, sequencing, chromametry, pH-metry, rheological methods, methods for determining the antioxidant ability of bread samples with microalgae for ferric reduction and removal of active free radicals were used for the research. When baking bread, the organoleptic, physicochemical properties, density, coefficients of elasticity, chewiness, stickiness, resistance to crumbling, the content of polyphenols and volatile compounds in the samples of bread with microalgae were controlled. It was found that with a higher content of microalgae in bread (3% of the flour weight on dry basis), the color of the crust and crumb decreased due to the degradation of the pigment during baking. The specific volume of a loaf with a large amount of microalgae (5%) was lower than the volume of loaves with the addition of 1% and 3% microalgae. It is shown that the moisture content increased with an increase in the amount of microalgae in bread. Replacing wheat flour with the amounts of microalgae of 1% and 3% did not affect the pH and water activity in bread. With the addition of 5% microalgae, bread became more sour, sticky, with a slight “fishy” smell. The addition of more microalgae led to an increase in polyphenols in bread samples, and, accordingly, to an increased antioxidant capacity. In total, 42 volatile compounds were found in bread with microalgae, which makes it possible to obtain functional bread. It is assumed that in the future, bread with microalgae will be competitive with ordinary wheat bread due to improved nutritional and biological value.