Changes in the activities of antimicrobial, antitumor, and antioxidant properties of postbiotics (YCG) are related to changes in the composition of phenolic compounds. Antimicrobial activity was found to be highest in postbiotic (YCG-7) against P. aeruginosa, S. aureus, and E. faecalis with an MIC of 3.1 µg/mL. YCG-7 revealed the most cytotoxicity against LS-174T and PC-3 cell lines with an IC₅₀ of 5.78 and 6.56 µg/mL, respectively. YCG-7 was far more effective for scavenging free radicals in the NO^• and DPPH assays with a scavenging activity of 70.73% and 85.6%, respectively. YCG-7’s total phenolic acid content is up to eightfold higher compared with control. Escherichia coli Nissle 1917 retained high viable counts during refrigerated storage, particularly in YCG (>10⁸ cells g⁻¹) revealing a potential prebiotic activity of Cape gooseberry juice. EcN affected the phenolic profile of the YCG. Pyrogallol, p-coumaric acid, ellagic acid, 4-hydroxybenzoic acid, salicylic acid, gallic acid, vanillic acid, o-coumaric acid, caffeic acid, catechol, syringic acid, and rutin were the predominant phenolic compounds in YCG-7 or YCG-15. Chlorogenic, rosmarinic, cinnamic acid, naringin, and kaempferol were degraded by EcN in YCG-7 and YCG-15. The YCG had significantly higher sensory scores for appearance, smoothness, sourness, mouthfeel, and overall acceptance. These results provide the basis to target the functional benefits of YCG for further human health applications.

India and Ethiopia employ Guizotia abyssinica (niger plant) as a source of edible vegetable oil. Previous studies have documented the niger plant’s antioxidant properties and dietary benefits. Here, G. abyssinica extract was obtained and ten known bioactive components (1–10) were isolated. The antioxidant, antidiabetic, and prebiotic properties of whole extract and isolated components of niger and the plant’s ability to cooperate symbiotically with probiotic strains were examined. Compound 10, myricetin-3-O-L-rhamnoside, had the highest antioxidant capacity measured in the 2,2-diphenylpicrylhydrazyl (DPPH, 4629.76 ± 6.02 µmol Trolox equivalent/g compound) and ferric-reducing antioxidant power (FRAP, 2667.62 ± 7.5 mol Trolox equivalent/g compound) assays. The lowest α-amylase and glycogen phosphorylase activities and glucose diffusion were obtained with whole G. abyssinica extracts, whereas compounds 8–10 had moderate inhibitory effects. G. abyssinica extract also induced the highest glucose absorption by yeast cells in the presence of 5 mM of glucose. Moreover, Lactobacillus plantarum and L. rhamnosus incubated with β-sitosterol 3-O-D-glucoside (compound 7) showed the highest prebiotic activity score. The levels of L-(+)-lactic acid isomer in the probiotic strains were the highest in presence of the whole extract and decreased progressively in the presence of flavonoid glycosides (compounds 8–10) and β-sitosterol 3-O-D-glucoside. The enzymatic profile of the probiotic strains was unaffected by the niger extract and compounds 7–10. The findings revealed that the biological activities of G. abyssinica extract are mediated by the compounds 1–10, and it may be considered as a promising plant for the treatment of diabetes mellitus.

Cyperus conglomeratus has been utilized in traditional medicine as an emollient, diuretic, analgesic, anthelmintic, and for other diseases. Furthermore, several biological activities have been reported for the plant extract and the isolated metabolites. The chromatographic investigation of an ethyl acetate extract of the aerial parts led to the isolation of three aurone derivatives (1–3) from the plant for the first time. Their structures were identified as aureusidin (1), aureusidin-4-methyl ether (2), and 5-methyl aureusidin (3) using 1D and 2D NMR techniques, along with mass spectrometry. The compounds were tested for their inhibitory activities against enzymes vital in metabolic diseases, especially diabetes, such as α-amylase, α-glucosidase, and glycogen phosphorylase. The results were expressed as percentage inhibition. The inhibitory activity of aurones against the tested enzymes was also analyzed by computational docking studies to provide a rational explanation for the observed results. The tested compounds formed stable interactions in terms of hydrogen bonding and hydrophobic interaction with the active site residues of the tested enzymes, and the results are in agreement with those of the in vitro antidiabetic activity. The compounds were also evaluated for their ability to support the growth and viability of beneficial bacteria in terms of prebiotic activities using two species, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus, through the determination of prebiotic activity scores (P_score). The findings of this study showed that C. conglomeratus is a potential natural source of bioactive agents. There is, however, a need for in vivo testing to evaluate this plant’s efficacy for developing new drug entities in the future.

Passion fruit peel powder (PFPP) was used to supplement the probiotic labneh to increase the activity of Escherichia coli Nissle 1917 (EcN) during production and storage. Labneh was manufactured with PFPP (0.5% and 1%) and analyzed at 0, 7, and 15 days of cold storage for postacidification and sensory properties and viability of EcN, survival of EcN to simulated gastrointestinal tract stress, and adhesion potential of EcN to Caco-2 cells. Acidification kinetics during fermentation showed that supplementation with PFPP reduced the time needed to decrease pH and reach the maximum acidification rate. PFPP addition contributed to postacidification of labneh during storage. PFPP had a beneficial effect (p < 0.05) on counts of EcN in labneh during different storage periods. Consumer preference expectations for labneh enriched with PFPP (0.5% and 1%) were higher than those for the control. PFPP provided a significant protective action for EcN during simulated gastrointestinal transit and had a positive effect on EcN adhesion to Caco-2 cells in vitro, although this decreased during storage with labneh. Labneh supplementation with PFPP can be recommended because of the positive effect on EcN viability and the high nutritional value, which may increase the appeal of the product to consumers.