We investigated the influence of different rootstocks on the content of sugars, organic acids, and antioxidant phenolic compounds in the whole fruit and fruit skin of the European plum cultivar “Čačanska Lepotica”. ¹H NMR of the fruit extracts allowed for the identification of sucrose, α- and β-glucose, sorbitol, fructose, and malic and quinic acids, while LC–DAD–ESIMS showed the presence of neochlorogenic and chlorogenic acids, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, peonidin-3-O-rutinoside, hyperoside, isoquercitrin, rutin, and unidentified quercetin-3-diglycoside. The quantitation of the sugars, malic and quinic acids by ¹H NMR and phenolic compounds by HPLC–DAD revealed that the rootstock significantly influenced the content of the individual compounds in the fruit skin and fruit. The fruit grafted on “Wavit” rootstock was characterized by significant amounts of neochlorogenic acid, peonidin-3-O-rutinoside, cyanidin-3-O-rutinoside, and sucrose, while the fruit on “GXN-15” was characterized by high levels of sugars, cyanidin-3-O-glucoside, and malic and chlorogenic acids. The fruit skins of plums grafted on “Wavit” were the richest in sugars, organic acids, and phenolic compounds. A good correlation was observed between the content of total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and individual phenolic compounds in the extracts of the fruit and the fruit skins and their antioxidant capacity (DPPH, ABTS, and FRAP).

Gamma irradiation has been applied as an efficient and inexpensive method for the sterilization of nuts for years. However, along with the benefits of such treatment, negative effects are possible because of the formation of reactive oxygen species with a toxic effect on important biologically active substances. Because of the scarce and contradictory information in the literature about gamma-irradiated almonds, the aim of our work was the examination of the lipid changes, antioxidant activity, and oxidative stability of almonds treated by 10 and 25 kGy gamma rays, as well as changes in intensity of the EPR spectra as an indicator for the stability of radiation-induced free radicals. The results revealed no significant differences in the EPR spectra of almonds treated at 10 and 25 kGy doses, neither in their intensity nor in kinetic behaviour. The EPR signals decayed exponentially over 250 days, with a decreasing of central line by 90%, with satellite lines by about 73%. No significant changes in the fat content, fatty acids composition, and acid value of irradiated almonds were observed. However, the amount of (alpha)tocopherols decreased from 292 to 175 mg/kg, whereas the conjugated dienes and trienes increased, K₂₃₂ from 1.3 to 3 and K₂₆₈ from 0.04 to 0.15, respectively, with the increasing of irradiation dose. The same was observed for total polyphenols in defatted almonds (1374 to 1520 mg/100 g), where in vitro antioxidant activity determined by ORAC and HORAC methods increased from 100 to 156 µmol TE/g and from 61 to 86 µmol GAE/g, respectively. The oxidative stability of oil decreased from 6 to 4 h at 120 °C and from 24.6 to 18.6 h at 100 °C (measured by Rancimat equipment). The kinetic parameters characterizing the oxidative stability of oil from 10 kGy irradiated almonds were studied before and after addition of different concentrations of ascorbyl palmitate as a synergist of tocopherols. Its effectiveness was concentration-dependent, and 0.75 mM ensured the same induction period as that of non-irradiated nut oil. Further enrichment with alpha-tocopherol in equimolar ratio with palmitate did not improve the oil stability. In conclusion, gamma irradiation is an appropriate method for the treatment of almonds without significant changes in fat content and fatty acids composition. The decreasing of oxidative stability after higher irradiation could be prevented by the addition of ascorbyl palmitate.

In the present study, the plant extract Melissa officinalis (M. officinalis) was successfully loaded in polymer fibrous materials on the basis of a biodegradable polyester–poly(L-lactide) (PLA) and biocompatible polyether–polyethylene glycol (PEG) by applying the electrospinning method. The optimal process conditions for the preparation of hybrid fibrous materials were found. The extract concentration was varied—0, 5 or 10 wt% in respect of the polymer weight, in order to study its influence on the morphology and the physico-chemical properties of the obtained electrospun materials. All the prepared fibrous mats were composed of defect-free fibers. The mean fiber diameters of the PLA, PLA/M. officinalis (5 wt%) and PLA/M. officinalis (10 wt%) were 1370 ± 220 nm, 1398 ± 233 nm and 1506 ± 242 nm, respectively. The incorporation of the M. officinalis into the fibers resulted in slight increase of the fiber diameters and in increase of the water contact angle values to 133°. The presence of the polyether in the fabricated fibrous material assisted the wetting of the materials imparting them with hydrophilicity (the value of the water contact angle become 0°). Extract-containing fibrous materials displayed strong antioxidant activity as determined by the 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical method. The DPPH solution color changed to yellow and the absorbance of the DPPH radical dropped by 88.7% and 91% after being in contact with PLA/M. officinalis and PLA/PEG/M. officinalis mats, respectively. These features revealed the M. officinalis—containing fibrous biomaterials promising candidates for pharmaceutical, cosmetic and biomedical use.

Gamma irradiation is efficiently applied to many foods, but nevertheless there is a distinct lack of information about the changes of macro- and micronutrients (e.g., carbohydrates, lipids, organic acids, and phenolics) in dried rose hip (RH) fruits. Therefore, in this study, for the first time, the effect of gamma irradiation (10 and 25 kGy) on RH constituents is investigated. Different analytical techniques (GC-FID, HPLC-UV, HPSEC-RID, IR-FT, and SEM) are employed to examine this effect. The irradiation treatment (10 kGy) increased the glucose content by 30% and released cellobiose from RH fruits, thus revealing cellulose destruction. The extractability of total uronic acids increased from 51% (control) to 70.5% (25 kGy-irradiated), resulting in a higher pectin yield (10.8% < 12.8% < 13.4%) and molecular heterogeneity. Moreover, de-esterification was not a major effect of the irradiation-induced degradation of pectin. The sample exposure to the highest dose did not change the content of total carotenoids, β-carotene, and (un)saturated fatty acids, but it affected the tocopherols levels. Gamma rays had a negligible effect on the phenolic constituents and did not affect ORAC and HORAC antioxidant activity. In conclusion, it can be compromised that the exposition of dried RH is safe and can be successfully applied to decontaminate fruits without affecting their nutritional value and biological activity.

Alkanna tinctoria L. Tausch (“alkanet” or “alkanna”) is a medicinal plant. Extracts from alkanet roots have applications as natural food coloring agents. In addition, they have proven antioxidant effects. Three classical solvents (ethanol and acidified ethanol/water) and four natural eutectic solvents (NADES)—choline chloride/urea; choline chloride/citric acid; choline chloride/lactic acid; and sodium acetate/formic acid—were compared for their effectiveness as “green” solvents for the extraction of the alkanet pigment. Notably, this study is the first to apply choline chloride-based NADESs for alkanet extraction, providing a comprehensive profile of key bioactive compounds and their contributions to antioxidant activity using UV/Vis and FT-IR spectrometry, GC-MS, and HPLC-PDA-MS. Among the classical solvents, 50% acidified ethanol showed the highest extraction capacity, as indicated by its total flavonoid (708 ± 32 mgCE/L) and total phenolic (1318 ± 63 mgGAE/L) content. However, this extract exhibited the highest total alkaloid content (256 ± 15 µg/L) compared to the other classical extraction solvents. Consequently, absolute ethanol was identified as a more suitable alternative. Among the NADES, the sodium acetate/formic acid (1:2 mol/mol, NADES4) extract was the only one to show the presence of alkannins. This extract also contained high levels of phenols (355 ± 21 mg GAE/L) and tannins (163 ± 10 mg CE/L), exhibited strong antioxidant potential (DPPH: 131 µmol TE/g dw, FRAP: 7.49 mg Fe(II)/mg dw), and contained significantly lower alkaloid levels (7.0 ± 0.5 µg/L). Comparative analyses indicated that the sodium acetate/formic acid extract outperformed those prepared with ethanolic solvents and other NADES.

Recently, previously known viruses have changed their pathogenicity and encompassed new types of host populations. An example of such an infection is that caused by SARS-CoV, belonging to the “well-known” coronavirus family. Another group of viruses that are of great importance to the human population are the herpes viruses. Due to increasing viral resistance to existing antiviral drugs, plant extracts are attracting increasing interest due to their complex composition and their simultaneous attack of different viral targets. Based on the above, we tested the antiviral potential of water–alcoholic extract obtained from a commercial sample of the plant Cistus incanus L. against the enveloped viruses SvHA1, SvHA2 (ACV resistant) and HCoV 229E. The results showed both complete inhibition of the intracellular stages of the viral replication and a strong effect on extracellular virions in the three viral models. In a study of the effect on the replication of SvHA 2, the calculated selectivity index was over 10. From the experiments on the virucidal effects on the two herpes viruses, it was found that the viral titer of the samples decreased by about 4 lg compared to the control sample. The extract is of interest for introduction into practice.