Natural Products and Bioactive Compounds

The use of bacteria and/or their compounds is an alternative to the use of positive-list additives that the food industry is using as a tool to meet consumer demands for more natural, long-shelf-life, and healthy products, in short, to offer clean label foods. The aim of this study is to investigate the suitability of cell-free supernatants (CFSs) from Qualified Presumption of Safety strains as bioprotective cultures. Out of an initial screening panel of about 200 isolates, strains Pediococcus acidilactici CNTA 1059, Lactiplantibacillus plantarum CNTA 600, Levilactobacillus brevis CNTA 1374, and Bacillus subtilis CNTA 517 demonstrated strong antimicrobial activity against, especially, Gram-positive bacteria. The CFSs of these four strains showed minimum inhibitory concentration values between 0.15% and 5% against Listeria monocytogenes and Lentilactobacillus parabuchneri. None of the four selected strains exhibited acquired resistance to target antibiotics, and the non-toxigenicity of all the CFSs was demonstrated. In the case of the three lactic acid bacteria, the presence of bacteriocin-like inhibitory substances was confirmed following the decline in antimicrobial activity due to treatment with proteases. Regarding B. subtilis, biosynthetic gene clusters for different bacteriocin-like substances, including protease-resistant lipoproteins, were found via whole-genome sequencing. In addition, all of the CFSs exhibited stable antimicrobial activity at a wide range of temperatures (70–121 °C) used for the pasteurization and sterilization of food products, with a loss of antimicrobial activity ranging from 3% to 28%. These results point to the possibility that CFSs from these strains could be used in the food industry as a biocontrol tool to develop new products. Full article

In order for a strain to be considered a probiotic or suitable plant bioprotective agent, it must have proven antimicrobial activity against pathogenic bacteria and phytopathogenic fungi. Bacillus amyloliquefaciens M exhibited significantly high antifungal activity against pathogenic fungi of the genera Aspergillus, Penicillium, Fusarium, and Sclerotinia; yeasts of the genera Candida and Saccharomyces; as well as high antibacterial activity against pathogens of the genera Escherichia, Salmonella, Staphylococcus, Listeria, Pseudomonas, and Bacillus. The manifested antimicrobial activity was influenced by the composition of the growth medium. The antifungal activity of the strain was investigated at growth temperatures of 30 °C and 37 °C, and at different pH values in aerobic and anaerobic cultivation, under static and dynamic culturing conditions. High antifungal activity was observed at the 24th h on both growth media (LBG broth and MPB broth) at pH = 6 and pH = 7 in aerobic and anaerobic cultivation. Bacillus amyloliquefaciens M produced antibiotic substances at pH > 5.0, and the antibiotic substances were either secreted into the medium or associated with the cell surface. Four compounds with different antifungal activity and different R_f values were registered through thin-layer chromatography (R_f1 = 0.47; R_f2 = 0.55; R_f3 = 0.67; and R_f4 = 0.75), two of the compounds were ninhydrin-positive. Bacillus amyloliquefaciens M was cultured in a bioreactor with stirring, and the parameters of the growth kinetics and the sporulation kinetics have been modeled. A spore concentrate of Bacillus amyloliquefaciens M has been obtained. In further research, the efficiency of the concentrate as a plant bioactive agent will be tested. Full article

To improve the nutritional value of bread, as well as to satisfy consumers whose awareness of the importance of nutrition to preserve health is growing significantly, it is desirable to enrich bread and bakery products with functional components. Carob (Ceratonia siliqua L.) is an evergreen tree that is widely distributed in the Mediterranean region and belongs to the legumes group. As carob pulp contains a unique combination of polyphenolic compounds and dietary fibre, it can be a useful raw material for the production of enriched bakery products. In this work, the possibility of applying carob extract as a potential natural preservative and functional additive in the production of bread was investigated. With this aim, 0.5, 1.5, 2.5 and 3.5% of powdered carob extract (CP) were added to bread dough and the quality characteristics of the bread were examined. The microbiological quality of bread was significantly better in samples with the addition of CP, which was confirmed by the lower values of the total number of bacteria and the absence of the Bacillus cereus. The addition of up to 3.5% carob extract had no negative effect on the sensory quality of the bread. The brightness of the bread samples decreased (L*), while the proportion of the red tone (a*) increased, and the intensity of the yellow tone (b*) decreased with an increase in the proportion of CP. The amount of total phenols (0.27 mg GAE/g) for the sample with 3.5% CP in bread was significantly higher compared to the control sample (0.12 mg GAE/g). The total antioxidant activity also increased significantly with the increase in the proportion of CP. Therefore, the present study proves that powdered carob extract can be successfully included in the production of a healthy functional food. Full article

Fennel essential oil (EO) is well known for its biological activities and wide potential for use in the food, cosmetic, and pharmaceutical industries, where the main challenge is to achieve higher stability of EO. This study aimed to evaluate the potential of electrostatic extrusion for encapsulation of fennel EO by examining the effects of alginate (1%, 1.5%, and 2%) and whey protein (0%, 0.75%, and 1.5%) concentrations and drying methods on the encapsulation efficiency, loading capacity, bead characteristics, and swelling behavior of the produced fennel EO microbeads. Results revealed that electrostatic extrusion proved to be effective for encapsulating fennel EO, with whey protein addition enhancing the examined characteristics of the obtained microbeads. Freeze-drying exhibited superior performance compared to air-drying. Optimal encapsulation efficiency (51.95%) and loading capacity (78.28%) were achieved by using 1.5% alginate and 0.75% whey protein, followed by freeze-drying. GC-MS analysis revealed no differences in the qualitative aspect of the encapsulated and initial EO, with the encapsulated EO retaining 58.95% of volatile compounds. This study highlighted the potential of electrostatic extrusion using alginate and whey protein as a promising technique for fennel EO encapsulation while also emphasizing the need for further exploration into varied carrier materials and process parameters to optimize the encapsulation process and enhance product quality. Full article

Background: Baobab fruit is valued for its nutritional and medicinal benefits. Although it is acknowledged that baobab pulp is beneficial for health, studies that link its nutraceutical properties to the ability to eliminate reactive species (ROS and RNS) are scarce. Methods: The nutritional profile and the antioxidant properties of baobab pulp extracts from Angola were evaluated. Thus, for the first time, the evaluation of in vitro scavenging capacity against the most physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) were the focus of investigation. Results: Angolan fruit pulp presented high contents of ash (8.0%) and total dietary fiber (52%). Vitamin E content was reported for the first time in fruit pulp. Green solvents were used to quantify bioactive compounds and antioxidant activity. Hydroalcoholic extracts exhibited the highest contents of phenolics (1573.0 mg/100 g) and flavonoids (768.7 mg/100 g). Thus, hydroalcoholic extracts showed higher antioxidant activity, and higher scavenging capacity for ROS (O₂^•−, H₂O₂, HOCl, ROO^•) and RNS (^•NO, ONOO⁻), being most active for ^•NO and ONOO⁻. Conclusion: For the first time, Angolan baobab fruit was described in respect to its nutritional contribution as well as its positive antioxidant effects, both as a functional food and as a nutraceutical ingredient. Full article

Sea cucumbers from unharvested areas, are underutilized resources which may have the potential to become a future food resource. The aim of this study was to evaluate protein quality and investigate the changes in antioxidant activity from frozen and freeze-dried red sea cucumber (Parastichopus tremulus) subjected to digestion, using an in vitro digestion model. P. tremulus constituted high moisture content (90%), comparable protein (4%) and ash (4%) content, and low lipid (1%) content. The biochemical components in freeze-dried samples were largely retained during the freeze-drying process. Frozen samples showed significantly higher (p < 0.05) antioxidant activity compared to freeze-dried samples (calculated on a dry weight basis). The quantity of essential amino acids was high (31%) and corresponds to the Food and Agriculture Organization of the United Nations reference protein. Frozen samples showed an increase in antioxidant activity during digestion measured by three different antioxidant assays. Freeze-dried samples only showed an increase in one of the antioxidant assays. Correlations (p < 0.05) were found between specific free amino acids and antioxidant activity. The amount of free amino acids exceeded the threshold to taste bitter, umami, sour, and sweet flavors. This study showed that P. tremulus constitutes good protein quality, performed antioxidant activity, and has the potential to be used as a flavor-enhancing ingredient. Full article

In Mexico, the tradition of consuming flowers dates to pre-Columbian times, and flower consumption persists today; however, this practice is typically unknown outside the regions where flowers are used in local gastronomy. The aim of this work was to evaluate the variation in polyphenol and flavonoid contents and antioxidant activity in inflorescence samples. Samples of izote (Yucca filifera), maguey pulquero (Agave salmiana), cuachepil or guachepil (Diphysa americana), and tepejilote or pacaya (Chamaedorea tepejilote) were collected from different communities and regions of Oaxaca, Mexico, during 2022. Specifically, ten to eleven inflorescence samples were collected per species, and their polyphenol and flavonoid contents and antioxidant activity were evaluated using UV–visible spectrophotometry and reference standards. Significant differences were detected between and within samples depending on their geographical origin (collection locations); the environment and site influenced the composition of the samples for each species. Across all species, significant and positive correlations of the polyphenol and flavonoid contents were identified with the antioxidant activity detected via the DPPH and FRAP methods. The high variability in phenolic compound contents and antioxidant activity within each species shows that the nutritional and nutraceutical potential of flowers may complement diets at the family and communitarian levels. Full article

Species identification is the first step in the examination of newly isolated microorganism strains, including the cases when they are intended for application in the development of probiotic preparations or starters for different food products. The thorough identification process of newly isolated strains combines the application of different physiological, biochemical, and molecular genetic methods. The aim of the present study was to identify the species-level lactic acid bacteria (LAB) strains isolated from spontaneously fermented sourdoughs prepared from different flour types: Khorosan wheat, wheat, barley, buckwheat, spelled, spelt, and corn. Both classical phenotypic (cellular morphology characterization, and API 50 CHL) and molecular genetic methods (RAPD, ARDRA-analysis, 16S rDNA sequencing, and species-specific PCR) were applied. It was found that cultures with a short-rod morphology predominated among the 30 sourdough isolates. According to the RAPD profiles obtained, the isolates were divided into nine genotypes corresponding to nine genetically distinct strains. It was determined that individual sourdoughs made with different flour types shared cultures with a common genotype. The analysis of the physiological and biochemical profiles of the LAB isolates performed with the API 50 CHL system divided them into two groups according to their identification: Lactiplantibacillus plantarum (Lp. plantarum) 1 and Levilactobacillus brevis (Lv. brevis) 3. According to the 16S rDNA restriction profile, the LAB isolates showed two profiles corresponding to the Lp. plantarum and Lv. brevis groups. 16S rDNA sequencing and a comparison of the partially read 16S rDNA sequences of the studied isolates confirmed that some of them belonged to the Lv. Brevis species, but did not provide sufficient evidence that the rest of the cultures belonged to the Lp. Plantarum species. The species-specific PCR clearly separated the isolates from the Lp. plantarum group into two groups: isolates of the Lp. plantarum species and isolates of the Lp. paraplantarum species. The summary of the results of the conducted polyphasic taxonomic study determined the investigated LAB strains isolated from spontaneously fermented sourdoughs as representatives of the Lv. brevis, Lp. plantarum ssp. paraplantarum, and Lp. paraplantarum species. Full article

This research involved synthesizing zinc salt-dependent zinc oxide nanoparticles (ZS-ZnO-NPs) using different zinc salts (ZnCl₂, ZnSO₄·H₂O, Zn(CH₃COO)₂·2H₂O, and Zn(NO₃)₂·6H₂O) and plant extracts of Phoenix dactylifera L. The synthesis efficiency was evaluated, and to carry out further investigations, zeta potential measurements, as well as SEM and TEM examinations, were performed to assess the morphology and size distribution of the nanoparticles. XRD and UV-Vis spectroscopy were also employed to confirm the crystalline nature and optical properties of the synthesized ZS-ZnO-NPs, respectively. FTIR analysis was also performed to identify chemical groups on the nanoparticle surface. Furthermore, the ZS-ZnO-NPs’ ability to scavenge free radicals (FRs^●), and thus their antioxidant capacity, was assessed using the DPPH FR^● assay. The results showed that the type of zinc salt used for the synthesis significantly influenced the yield, stability, optical properties, morphology, and size distribution of nanoparticles. The zinc salt-dependent yield exhibited a notable range, varying from 50.3% to 55.3%. The nanoparticle size ranged from 3.7 to 10.2 nm, with the zeta potential ranging from −28.6 to −46.7 mV and the gap energy (E_g) ranging from 3.28 to 3.39 eV. Moreover, the synthesized ZS-ZnO-NPs exhibited concentration and time-dependent inhibitory activity against DPPH FR^●, showing potential as antioxidant agents in biomedicine and other industries. Full article

Freeze-dried stems and caps of six cultivated mushroom species, namely Agaricus bisporus (white) Agaricus bisporus (brown), Lentinula edodes, Pholiota nameko, Pleurotus eryngii and Pleurotus ostreatus were subjected to ethanolic extraction. The obtained extracts were analyzed in terms of total phenolics content, total flavonoids content and antioxidant capacity, and the results were calculated per gram of mushroom dry weight and extract dry weight. The LC–MS technique was applied to determine the profiles of phenolic acids. The amount of total phenolics in the stems (per the fruiting bodies’ dry weight) ranged from 1.09 ± 0.09 mg/g (P. ostreatus) to 4.02 ± 0.20 mg/g (the white A. bisporus), whereas in the caps it ranged from 1.49 ± 0.07 mg/g (P. nameko) to 6.22 ± 0.21 mg/g (the brown A. bisporus). The total flavonoid content in the stems (per the fruiting bodies’ dry weight) varied from 0.46 ± 0.05 mg/g (P. ostreatus) to 1.72 ± 0.02 mg/g (the brown A. bisporus), and in the caps it ranged from 0.48 ± 0.01 mg/g (P. ostreatus) to 1.93 ± 0.05 mg/g (the white A. bisporus). The antioxidant potential measured with the FRAP assay showed that the caps displayed higher activity compared to the stems. However, in the case of the DPPH assay performed on A. bisporus, this relationship was inverted. Different species contained varied concentrations of phenolic acids. P. eryngii caps contained the highest amount of 3,4-DHBA, L. edodes caps were the richest source of caffeic acid, whereas the highest amount of syringic acid was observed in L. edodes stems. The caps of P. nameko contained the highest amounts of p-coumaric and t-cinnamic acid, as well as 4-hydroxybenzaldehyde. Full article

The current study aimed to appraise extracts of Cleome simplicifolia (Cambess.) Hook. f. and Thomson leaves for chemical integrant and biological activities. In this study, different extracts of leaves were estimated for qualitative phytochemical screening, identification of functional groups, mineral content, and phyto-compounds and assessed for in vitro antioxidant and in vivo acute toxicity and hepatoprotective activity antagonistic toward paracetamol-intoxicated Wister albino rats. The results of the qualitative phytochemical assessment of the leaf extracts (acetone, methanol, and distilled water) exhibited the occurrence of useful metabolites. A Fourier transform infrared analysis confirmed the occurrence of O-H, N-H, C=C, S=O, C-O, C-N, C-Cl, and C-Br at 3367.14, 2920.79, 2850.32, 1631.04, 1384.59, 1168.64, 1063.78, 824.78, and 615.25 cm⁻¹ wavelengths, whereas energy-dispersive X-ray showed the existence of carbon, oxygen, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, and calcium elements in the leaf, respectively. Thereafter, a gas chromatography–mass spectroscopy analysis unveiled the diverse volatile compounds in the methanolic leaf extracts, namely n-Heptyl acrylate—18.87%, undecane—17.49%, 2-Propenoic acid, 3-(3,4-dimethoxyphenyl)-, (E)—11.40%, Neophytadiene—11.02%, n-Hexadecanoic acid—10.78%, Glafenin—10.09%, Decane—7.45%, Phytol—6.0%, Benzene, (1-methyldodecyl)—3.48%, and 4-Cyclohexyl-1-butanol—3.41%, respectively. An analysis of in vitro antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl assay of methanolic leaf extract revealed elevated levels of antioxidant ability at 20 (46.18%), 40 (53.83%), 60 (66.64%), 80 (74.03%), and 100 (85.05%) μg/mL. In addition, in vivo acute toxicity determination proved that the methanolic leaf extract was innocuous and caused no mortality at 72 mg, 78 mg, or 82 mg/kg b.wt. doses. The methanolic leaf extracts’ in vivo hepatoprotective activity against paracetamol revealed significant efficacy at 50 and 100 mg/kg b.wt. via reduction of aspartate transaminase, alanine transaminase, alkaline phosphatase, bilirubin, and cholesterol (serum blood biochemical markers) followed by an enhancement in superoxide dismutase, catalase, and glutathione (liver antioxidants) with lipid peroxidation depletion compared with the normal group rats. From the investigated study, it was concluded that the C. simplicifolia leaf are a potential source for the isolation of biologically active phyto-compounds and have the ability to prevent liver damage by paracetamol induction, where the hepatic restoration ability is indexed to its in vivo and in vitro antioxidant ability, which might be the result of its chemical constituents. Full article