Antioxidant properties of medicinal plants and their effect on microbial spoilage of semi-finished meat, poultry and fish

Plant extracts rich in polyphenols can be used in the food industry as natural preservatives, extending the shelf life of prepared and semi-finished foods without chemical preservatives. In this paper, we investigate the polyphenolic composition, antioxidant activity and antibacterial properties of herbal extracts as part of food systems. The research objects were knot grass (Polýgonum aviculáre), marjoram (Oríganum), bur beggar-ticks (Bídenstripartíta), thyme (Thymus), whortleberry leaves (Vaccínium ida vítis), calendula (Calendula), sage (Salvia), chamomile flowers (Matricāriachamomīlla), eucalyptus (Eucalýptus) and bearberry (Arctostáphylosúva-úrsi). We determined the total content of phenolic compounds and flavonoids; the antioxidant activity by DPPH and FRAP methods; variations in the bacterial сontamination of animal raw materials over total bacterial count (TBC), coliform bacteria, yeast/fungi, salmonella and staphylococcus. Extracts of sage (1138±57 mg GA/100 g and 537±25 mg C/100 g), eucalyptus (1073±49 mg GA/100 g and 412±20 mg C/100 g), chamomile flowers (1002±36 mg GA/100 g and 493±22 mg C/100 g) and marjoram (1015±42 mg GA/100 g and 458±21 mg C/100 g) contain the largest amount of biologically active substances (phenols and flavonoids, respectively). Sage, eucalyptus and chamomile extracts demonstrate the highest antioxidant activity among the studied samples. Most of the studied extracts exhibit little or no effect on the organoleptic properties of finished products. In addition, chamomile flower, sage and eucalyptus extracts suppress the growth of pathogenic microorganisms in foods under experimental conditions. The microflora growth is significantly reduced when treating animal raw materials with calendula flowers, marjoram and thyme extracts. Extracts of sage, chamomile flowers, calendula flowers, marjoram and thyme can be recommended as components of food raw materials.

POLYPHENOLS IN OLIVE LEAVES AND THEIR ANTIOXIDANT ROLE -A BRIEF REVIEW

Exercise and sports can often be associated with oxidative stress, which is why modulation of oxidative stress in these situations is important. One of the natural remedies that has proven to be very useful antioxidant, due to its composition, is the oliveleaf extract.Olive leaves. The leaves are considered a by-product of the olive. Freezing techniques as well as leaf drying techniques influence the composition in polyphenols. The leaves have a high content of bioactive phenolic compounds. The most abundant compound in olive leaves is oleuropein, followed by hydroxytyrosol. Olive leaves have been used in the human diet in the form of extracts, tea and powder but also in the realization of traditional remedies in the Mediterranean countries. The compounds in olive leaves have been shown to have multiple beneficial properties, such as antioxidants. compared to olive oil.Instead of conclusions.Due to their rich polyphenolic composition, olive leaves have strong antioxidant effects, proven by traditional use and scientific studies.

Comparison of Different Extraction Solvents for Characterization of Antioxidant Potential and Polyphenolic Composition in Boletus edulis and Cantharellus cibarius Mushrooms from Romania

Edible mushrooms are well-known for their nutritional benefits and low energy density. In addition, mushroom extracts contain various bioactive compounds that account for their antioxidant activity; the applied extraction conditions influence the extraction efficiency of such compounds. Therefore, this study investigates the effects of four extractants on the content of polyphenols and antioxidant properties of Boletus edulis and Cantharellus cibarius mushrooms, aiming to optimize the extraction process. Powders of B. edulis and C. cibarius mushrooms were subjected to extraction with acidic water (10% CH3COOH), ethanol/water/acetic acid (15:76.5:8.5, v/v/v), hexane, and diethyl ether to measure their total phenolic content (TPC), total flavonoid content (TFC), and Trolox equivalent antioxidant capacity (TEAC). Furthermore, the level of individual polyphenolic compounds in these extracts was quantified using an HPLC-DAD-ESI-MS method. Results showed that the type of solvent significantly influenced the TPC and TEAC of mushroom powder but insignificantly influenced the TFC. A very strong positive correlation was found between TPC and TEAC, but no correlation was found between TFC and TEAC or TPC and TFC. Acidic water extracted the highest amount of polyphenolic compounds from these mushroom powders. Therefore, the aqueous extract showed the highest TPC and strongest antioxidant activity. Thus, acidic water is recommended for polyphenol analysis in B. edulis and C. cibarius mushrooms.

Chemical and Biological Profile and Allergenicity of Thymus baicalensis Plant of Mongolian Origin

Thymus baicalensis is a medicinal plant recognized as a traditional Mongolian therapeutic and health-promoting food supplement. The aim of the study was to check the suitability of the tested plant for supporting the treatment of certain diseases. The following study is the first one to showcase the versatile scope of characteristics of T. baicalensis, including its volatile oil composition, polyphenolic composition, lipid composition, phenolic and flavonoid contents, antioxidant activity, antimicrobial properties and ingestive allergenicity. Myrcene, at 26.15%, was shown to be the most abundant component of the volatile oil. Compounds known as inherent components of the Thymus genus: thymol and carvacrol made up only about 0.24% of the extracted oil. As much as 10.11 g kg−1 of polyphenol compounds were identified as derivatives of luteolin-7-O-glucuronide. The lipid extract was found to be rich in palmitic acid (31.05%), while unsaturated fatty acids were not reported. Spectrophotometric determination of the phenols and flavonoids indicated 7.541 mg of gallic acid g−1 and 4.345 mg of quercitin g−1, respectively. The free radical scavenging activity was determined by the 2,2-difenylo-1-pikrylohydrazyl method at IC50 = 206.97 µg mL−1. The extracts also had a strong inhibitory effect on M. flavus and P. fluorescenes bacteria, as well as S. cerevisiae yeasts. The Bet v 1 and profilin allergens in T. baicalensis were reported at 175.17 ng g−1 and 1.66 ng g−1, respectively.

Pressurized Liquid Extraction of Polyphenols and Anthocyanins from Saffron Processing Waste with Aqueous Organic Acid Solutions: Comparison with Stirred-Tank and Ultrasound-Assisted Techniques

Fοllow up with our previous study on the extraction of saffron processing waste polyphenols using deep eutectic solvents, the objective of this examination was a comparative evaluation of pressurized liquid extraction (PLE), stirred-tank extraction (STE) and stirred-tank extraction with ultrasonication pretreatment (STE/UP) with respect to the recovery of pigments and antioxidant polyphenols from saffron processing waste. Aqueous solutions of citric and lactic acids at two different concentrations were used as green solvents. The extracts obtained under the specified conditions were analyzed for total pigment and total polyphenol yields as well as for their ferric-reducing power and antiradical activity. Furthermore, each produced extract was analyzed with liquid chromatography–mass spectrometry to profile its analytical polyphenolic composition. In all cases, PLE provided inferior results compared to the two other techniques, producing extracts with lower polyphenolic concentration and weaker antioxidant properties. On the other hand, no specific pattern was detected concerning the effect of ultrasonication, acid type and acid concentration. Hierarchical cluster analysis indicated that stirred-tank extraction with 1% (w/v) lactic acid and ultrasonication pretreatment might be the highest-performing combination, providing extracts with increased polyphenol and pigment concentration; however, it also enhanced antioxidant activity. It was also concluded that the significantly shorter extraction time when using PLE might be an important element in further optimizing the process, buttressing the use of this technique for the establishment of innovative and sustainable-by-design extraction methodologies.

Polyphenols content of selected medical plants and food supplements present at Bulgarian market

Background: Medicinal plants are a rich source of antioxidant polyphenols and in particular flavonoids. Materials and methods: In the present study 5 Bulgarian medical plants and 5 food supplements, present at the Bulgarian market, are analyzed for their Total phenolic, Total flavonoids and selected individual flavonoids content. A HPLC method was developed and validated for simultaneous determination of (+)-catechin, (-)-epicatechin and rutin in plant and supplements, using PDA detection. Results: The results show that polyphenols in the selected food supplements are lower than those of the medical plants analyzed. Mentha piperita and Melissa officinalis have the highest polyphenols content (67.38 and 65.17 mg GAE/g; 54.59 and 57.76 mg RE/g respectively). Rutin was detected in all samples analyzed, reaching highest levels in Mentha piperita (7332.5 µg/g), followed by fruits of Sambucus nigra (2818.7 µg/g). Conclusion: The results of the study are a practical contribution to a more complete characterization of the polyphenolic composition in Bulgarian medicinal plants.

The Bark of Picea abies L., a Waste from Sawmill, as a Source of Valuable Compounds: Phytochemical Investigations and Isolation of a Novel Pimarane and a Stilbene Derivative

In this work, the sawmill waste from Picea abies debarking was considered as source of valuable phytoconstituents. The extraction was performed using different ethanol/water mixtures, and characterization was obtained by LC-MSn. This latter revealed flavonoid glycosides, lignans, and procyanidins. Extraction with organic solvents (dichloromethane and methanol) and chromatographic separations of the obtained extracts by silica column followed by semi-preparative HPLC led to the isolation of polyphenols and terpenoids such as 21α-metoxy-serrat-14-en-3-one, 21α-hydroxy-serrat-14-en-3-one, pinoresinol, dehydroabietic acid, 15-hydroxy-dehydroabietic acid, 7-oxo-dehydroabietic acid, pimaric acid, 9β-pimara-7,15-dien-19-ol, 13-epi-manoyl oxide, taxifolin-3’-O-glucopyranoside, trans-astringin, and piceasides. Piceaside V and 9β-pimara-7-keto-19β-olide, two novel compounds identified for the first time in P. abies bark, were isolated, and their structures were elucidated using 1D and 2D NMR and MS techniques. The polyphenolic composition of the methanolic portion was also investigated using LC-MSn, and the piceaside content was estimated. To assess the antioxidant activity of main constituents, semi-preparative HPLC was performed on the methanolic extract, and the obtained fractions were assayed by using the DPPH test. Overall, this work shows the potential usefulness of P. abies bark as a source of valuable phytochemicals.

Improvement of the quality in hydroponically grown fresh aromatic herbs by inducing mild salinity stress is species-specific

Profitable hydroponic production requires high quality fresh water, which is often not available for agricultural use, while desalinisation of salty water is an expensive and unsustainable technology. In the present study, we assessed the effect of mild salinity stress during the soilless cultivation of fresh peppermint and spearmint in the floating system on biomass yield, produce quality and plant secondary metabolite content. Peppermint and spearmint plants were grown for 25 days on a nutrient solution (NS) supplemented with three different NaCl concentrations (0 mM, 10 mM or 20 mM NaCl). The plant height, root length, fresh and dry weight were recorded and composition was determined on fresh tissue. The composition of essential oil was determined upon hydrodistillation and that of polyphenolic compounds by targeted ultra-performance liquid chromatography coupled with mass spectrometer (UPLC-MS/MS). Plant growth was not suspended by the addition of NaCl in the NS, except for the plant height at the highest salinity level. In peppermint, the nutritional composition was not affected by the salinity, whereas it was significantly improved in spearmint as confirmed by the nitrate content decrease and the total antioxidant capacity, total soluble phenol, total carotenoid and essential oil content increases. Simultaneously, no effect of the salinity on essential oil or polyphenolic composition in both plants was induced. In conclusion, peppermint and spearmint production is feasible in the floating system even under mild salinity conditions, without negatively affecting either the crop yield or the plant's essential oil or phenolic composition. Indeed, low salinity levels improved the nutritional composition of spearmint plants.