3-Hydroxyneocryptolepine, a new indoloquinoline alkaloid from the roots of Cryptolepis sanguinolenta (Lindl.) Schltr.

Phytochemical investigations of the African ethnomedicinal plant Cryptolepis sanguinolenta (Lindl.) Schltr. (Apocynaceae) have yielded only a small number of rare naturally occurring indoloquinoline alkaloids. Our recent work has resulted in the isolation of a new indoloquinoline named 3-hydroxyneocryptolepine, which was obtained from an ethanolic extract of the roots. The structure of the compound was elucidated based on 1D and 2D NMR as well as HRESIMS spectral evidence. LDL uptake promotion activity of the compound in HepG2 cells was not significant.

Cheese Whey Protein and Blueberry Juice Mixed Fermentation Enhance the Freeze-Resistance of Lactic Acid Bacteria in the Freeze-Drying Process.

The effects of MRS, whey protein and blueberry alone, and mixed fermentation on the survival rate of lactic acid bacteria under various freeze-drying conditions were investigated. The surface structure of the freeze-dried powders was also investigated to explore the anti-freezing protection mechanism of mixed whey protein and blueberry fermentation on the bacteria. It was found that the mixed fermentation medium of blueberry and whey protein has a protective effect on the freeze-drying bacteria and is better than the traditional MRS and whey protein medium. The optimal concentration of blueberry juice addition was 9%. The survival rate of the pre-freezing temperature at -80 °C was higher than at -20 °C after the pre-freezing and freeze-drying processes. The freeze-drying thickness of 0.3 cm could improve the survival rate of the bacteria. The Fourier transform infrared spectroscopy results indicated the interaction between the whey protein, anthocyanins, and the surface composition of the lactic acid bacteria.

Sesquiterpene lactones from Tithonia diversifolia with ferroptosis-inducing activities.

Eight previously undescribed sesquiterpene lactones (1-8), together with six known ones (9-14) were isolated from the aerial parts of Tithonia diversifolia (Hemsl.) A. Gray. The absolute configurations of these compounds were elucidated using HRMS, NMR spectroscopy, optical rotation measurements, X-ray crystallography, and ECD. Among them, sesquiterpene lactones 2-4 share a unique carbon skeleton with a rare C-3/C-4 ring-opened structure. Compounds 1 and 8 showed moderate inhibitory effects toward CT26 murine colon carcinoma cells by promoting lipid ROS production, highlighting their potential as ferroptosis inducers.

Haperforatones A-M, thirteen undescribed limonoids from Harrisonia perforata with anti-inflammatory activity.

UPLC-Q-TOF-MS combined with mass defect filtering strategies were applied for the phytochemical investigation of Harrisonia perforata, leading to the isolation of thirteen undescribed limonoids named haperforatones A-M (1-13) and seventeen known compounds (14-30). Particularly, haperforatones D-E (4-5) have an unprecedented A, B, C, D-seco-6, 7-nor-C-24-limonoid skeleton, structurally stripped of the five-membered lactone ring B and formed a double bond at the C-5 and C-10 positions. Their 2D structures and relative configurations were identified using spectroscopic data. The absolute configurations of 1, 4, and 6 were established via X-ray diffraction crystallography. All 30 compounds were evaluated for anti-inflammatory potential in LPS-induced Raw 264.7 cell lines. Among those tested compounds, the most potent activity against LPS-induced NO generation was demonstrated by haperforatone F (6), with the IC50 value of inhibition NO production of 7.2 µM. Additionally, 6 could significantly inhibit IL-1ß and IL-6 release and markedly downregulate the protein expression level of iNOS in the LPS-stimulated RAW264.7 cells at 10 µM. The possible mechanism of NO inhibition of 6 was also investigated using molecular docking, which revealed the interaction of compound 6 with the iNOS protein.

Amide alkaloids and neolignans from Piper hongkongense and their inhibitory activities of PCSK9 expression.

Four undescribed amide alkaloids hongkongensines A-C and 1-(1-oxo-6-hydroxy-2E,4E-dodecadienyl)-piperidine, five known amide alkaloids, and three known neolignans were isolated from the aerial part of Piper hongkongense. The planar structures of these compounds were determined by detailed analyses of HR-ESI-MS and NMR data. The absolute configurations of hongkongensines A-C were elucidated by single-crystal X-ray diffraction analysis and ECD calculations. Moreover, the inhibitory activities of PCSK9 expression in vitro for all compounds were assessed by PCSK9 AlphaLISA screening. Kadsurenone (10) displayed a significant inhibitory activity at 5 µM with an inhibition rate of 51.98%, compared with 55.55% of berberine (BBR 5 µM).

Dimeric ent-kauranoids isolated from Isodon japonica var. Glaucocalyx and their anti-inflammatory activities.

The phytochemical investigation of the aerial parts of Isodon japonica var. glaucocalyx afforded four undescribed (glaucocalyxin O-R, 1-4) and six known ent-kauranoids (5-10). Their structures were established using NMR and MS measurements. Compounds 1 and 2 are dimeric ent-kaurane-type diterpenoids. Moreover, the plausible biogenetic pathways for compounds 1 and 2 were proposed as Michael addition between two monomers. Eight compounds were assayed for their anti-inflammatory activity by evaluating NO production in LPS-induced RAW 267.4 cells, and compounds 7, 8 and 9 exhibited relatively remarkable anti-inflammatory activities at 10 µM.

Ionic regulation whey protein composition on membrane fouling during ultrafiltration process analyzed by HPLC.

In order to meet the market demand and avoid the increase of operation amount and cleaning cost in the process of ultrafiltration, it is particularly important to find more practical and efficient methods to control and improve membrane fouling. In this study, the ions in the ultrafiltration process were regulated to affect membrane surface proteins composition (lactoferrin, α-lactalbumin, ß-lactoglobulin A and ß-lactoglobulin B) and delay membrane fouling. It was found that Na+ (21 mmol/L), Zn2+ (0.25 mmol/L) and K+ (44 mmol/L) was added at 4 min, 8 min and 12 min, respectively during ultrafiltration process. The continuous regulation slowed down the decline rate of membrane flux and reduced the content of α-lactalbumin, ß-lactoglobulin A and ß-lactoglobulin B on the membrane surface analyzed by HPLC. This could reduce the irreversible membrane fouling of proteins cake resistance. Furthermore, the ions concentration was also investigated after filtration. The concentration of K+ was increased significantly and other ions concentration was not significantly changed after continuous regulation such Na+, Mg2+, Zn2+ and Ca2+ compared to control. Therefore, dynamic ionic regulation of whey protein ultrafiltration process is a simple and effective method, which provides technical theoretical basis for optimizing and improving membrane technology.

Eighteen iridoids from the roots and rhizomes of Valeriana jatamansi and their protective effects against α-hemolysin.

Thirteen previously undescribed iridoids (1-13), together with five known iridoids (14-18) were isolated from the roots and rhizomes of Valeriana jatamansi Jones. Their structures with absolute configurations were elucidated by analysis of MS, NMR, optical rotation and their experimental and calculated electronic circular dichroism spectra. All of the isolated compounds were tested for their protective effects against α-hemolysin-induced cell death in A549 cells. Compounds 14, 16 and 17 showed moderate protective effects, and compounds 15 and 18 showed weak protective effects.

Lindenane sesquiterpenoid dimers from Chloranthus japonicus improve LDL uptake by regulating PCSK9 and LDLR.

UPLC-TOF-MS/MDF directed phytochemical research of Chloranthus japonicus led to the isolation of 46 lindenane sesquiterpenoid dimers, which included 13 new analogs. Their structures with absolute configurations were elucidated by analysis of spectroscopic data. Fourteen compounds with ester chains significantly decreased PCSK9 protein level in medium of HepG2 cells, especially for compounds 14 and 29 (5 µM) with inhibition rates of 69.0% and 72.8%, respectively. Compound 14 in HepG2 cells was evaluated via DiI-LDL uptake assays and found to increase LDL uptake by upregulating LDLR mRNA and protein level. Meanwhile, 14 decreased the secretion of PCSK9 protein in medium and downregulated intracellular PCSK9 protein and mRNA level. The discovery of these natural small molecule compounds provides a novel structure basis for design PCSK9 regulators, making them a promising lead for development of new lipid-lowering agents.

Mitophagy-dependent mitochondrial ROS mediates 2,5-hexanedione-induced NLRP3 inflammasome activation in BV2 microglia.

We recently revealed a pivotal role of NLRP3 inflammasome in the neurotoxicity induced by n-hexane, owing to its activation and release of pro-inflammatory cytokines. However, the mechanisms of how the activation of NLRP3 inflammasome was triggered by 2,5-hexanedione (HD), the toxic product of n-hexane metabolism, remain to be explored. Here, we investigated whether mitochondrial reactive oxygen species (mtROS) was involved in HD-elicited NLRP3 inflammasome activation in microglia. We demonstrated that exposure to HD at 4 and 8 mM elevated production of mtROS in BV2 microglia. Scavenging mtROS by Mito-TEMPO, an mtROS scavenger, dramatically reduced HD-induced NLRP3 expression, caspase-1 activation and interleukin-1ß production, pointing a crucial role of mtROS in NLRP3 inflammasome activation. Mechanistic study revealed that HD intoxication promoted activation of mitophagy. HD induced expression of Beclin-1, LC3II, and two mitophagy-related proteins, i.e., Pink1 and Parkin and simultaneously, reduced p62 expression in both whole cell and isolated mitochondria of microglia. Furthermore, inhibition of mitophagy by 3-methyladenine (3-MA) greatly reduced production of mtROS, expression of mitochondrial fission-related proteins, dynamin-related protein 1 (Drp1) and fission protein 1 (Fis1) and activation of NLRP3 inflammasome in HD-intoxicated microglia. Blocking mitochondrial fission by Mdivi-1 also prevented HD-induced mtROS production and NLRP3 inflammasome activation in microglia. In conclusion, our data indicated that HD triggered activation of NLRP3 inflammasome through mitophagy-dependent mtROS production, offering an important insight for the immunopathogenesis of environmental toxins-induced neuroinflammation and neurotoxicity.

The Effect of Different Organic Acids and Their Combination on the Cell Barrier and Biofilm of Escherichia coli.

Organic acids are natural antimicrobial compounds commonly used in the food industry. In this study, acetic, lactic, butyric, citric, and malic acid at minimum inhibitory concentrations and their combinations at optimal inhibition concentrations were used to treat E. coli, and the effects on the cell barrier and biofilm of E. coli were evaluated. Acetic acid showed the highest membrane-damaging effect, while citric acid and malic acid could specifically damage the cell wall of E. coli, leading to alkaline phosphatase leakage. The RT-qPCR results showed that organic acids upregulated the membrane-protein-related genes of E. coli, and the combination of organic acids had a wider range of effects than single organic acid treatment. Moreover, organic acids inhibited the formation of E. coli biofilm and cellular activity within the biofilm. This study showed that the combination of organic acids plays a synergistic inhibitory role mainly through multiple destructive effects on the cell barrier and exhibited synergistic anti-biofilm effects. The three-three combination of acetic, lactic acid, and a third organic acid (butyric, citric, or malic) can play a better synergistic antibacterial effect than the two-pair combination of acetic and lactic acid. These findings have implications for the usage, development, and optimization of organic acid combinations.

Novel indoloquinoline alkaloid glycosides from Cryptolepis sanguinolenta (Lindl.) Schltr.

To explore the phytochemistry of the African ethnomedicinal plant Cryptolepis sanguinolenta (Lindl.) Schltr. (Apocynaceae) for rare indoloquinoline alkaloids, two novel indoloquinoline alkaloid glycosides, namely Cryptospirosanguine A (1) and B (2), were isolated from an ethanolic extract of the root. Their structures were elucidated based on spectral evidence. Furthermore, two known terpenoids were isolated from this plant for the first time.

The Characteristics of Whey Protein and Blueberry Juice Mixed Fermentation Gels Formed by Lactic Acid Bacteria.

The properties of blueberry juice and whey protein gels formed by the mixed fermentation of L. plantarum 67 and L. paracasei W125 were investigated. The state of the gels, including the colour and surface morphology of the microspheres, showed significant changes with different fermentation times. The polyphenolic, flavonoid, and protein release of whey protein or combined blueberry juice fermented gels under in vitro digestion were investigated. The whey protein and blueberry juice fermented gels had more small pores, with a honeycomb structure, compared to whey protein fermented gels. The hardness of the gels was increased after fermentation for 7 h for the whey protein gels and whey protein mixture blueberry juice gels. The storage modulus and water-holding capacity of the gels were increased between fermentation times of 6 h and 8 h. The swelling rates of the whey protein gels fermented for 7 h and whey protein mixed blueberry juice gels fermented for 8 h and kept in pepsin-free simulated gastric fluid for 1 h had higher values. The release of polyphenols, flavonoids, and protein for the fermented gels was higher at fermentation of 7 h in the in vitro digestion experiment. We found that the chewiness of the whey protein gels, or whey protein mixed fermentation gels, was higher at a fermentation time of 7.5 h and 8 h. However, the cohesiveness values were not significantly different. Therefore, whey protein fermented gels and whey protein mixed blueberry juice fermented gels should be fermented for more than 7 h. This facilitates the release of polyphenols, flavonoids, and protein in the gastric juices.

Five undescribed abietane-type diterpenes of Callicarpa macrophylla.

A phytochemical investigation of the medicinal plant Callicarpa macrophylla resulted in the characterization of two rare rearrangement abietane-type diterpenoids, macrophypene F-G (1-2), and three abietane diterpenoids, named macrophypene H-J (3-5). Additionally, five known diterpenoids (6-10) were identified. The structures of the newly discovered compounds were fully established through extensive analysis of HRESIMS, 1D and 2D NMR data. The absolute configurations of the isolated compounds were determined using CD comparison, chemical methods, and X-ray crystal diffraction experiments. Subsequently, all isolated diterpenoids were evaluated for their inhibitory effects on extracellular PCSK9 protein levels by PCSK9 AlphaLISA screening. Jiadfenoic acid B (6, 56.80% inhibition at 20 µM) and holophyllin F (10, 43.18% inhibition at 20 µM) significantly decreased PCSK9 protein levels in medium of HepG2 cells.

Five undescribed guanidine alkaloids from Plumbago zeylanica.

Five undescribed guanidine alkaloids, plumbagines HK (1-4) and plumbagoside E (5), as well as five known analogues (6-10) were isolated from the roots of Plumbago zeylanica. Their structures were established by extensive spectroscopic analyses and chemical methods. In addition, 1-10 were accessed their anti-inflammatory activities by measuring nitric oxide (NO) concentrations in LPS-induced RAW 264.7 cells. However, all compounds especially 1 and 3-5 could not inhibit the secretion of NO but significant increase the secretion of NO. The result reminded us that 1-10 may become potential novel immune potentiators.

Antioxidant capacity, flavor and physicochemical properties of FH06 functional beverage fermented by lactic acid bacteria: a promising method to improve antioxidant activity and flavor of plant functional beverage.

The ability of natural plants to treat chronic diseases is closely related to their antioxidant function. Lactic acid bacteria (LAB) fermentation is an effective way to improve the nutritional value, biological activity and flavor of food. This study investigated the pH, titratable acidity, total polysaccharide, total flavone, total saponin, total polyphenol, and antioxidant activity of the FH06 beverage before and after probiotic fermentation. Results: After fermentation, FH06 had lower contents of total polysaccharides, total flavonoids, total saponins and total polyphenols but higher titratable acidity. The antioxidant activity was tested by total antioxidant capacity (FRAP method) and DPPH· scavenging ability. The FRAP value significantly increased after fermentation (P < 0.05), and the maximum increase was observed for Lactobacillus fermentum grx08 at 25.87%. For DPPH· scavenging ability, the value of all fermentations decreased, and L. fermentum grx08 had the smallest reduction at 2.21% (P < 0.05). The results of GC-MS and sensory analysis showed that fermentation eliminated bad flavors, such as grass, cassia and bitterness, and highlighted the fruit aroma and soft sour taste. Conclusion: The FRAP value and sensory flavor of FH06 fermentation by L. fermentum grx08 were significantly improved, indicating its great potential as a functional food with both strong antioxidant activity and good flavor. Supplementary Information: The online version contains supplementary material available at 10.1186/s13765-022-00762-2.

Novel antioxidant peptides from MFGM protein Hydrolysates: Separation, identification and effects on Dexamethasone-induced mitochondrial dysfunction.

Milk fat globule membrane (MFGM) protein is a complex milk protein system with antioxidant property, which can alleviate skeletal muscle dysfunction caused by oxidative stress. In this study, peptide products of MFGM protein obtained through in vitro digestion were isolated and purified, and the composition and antioxidant activities of MFGM peptides (MFGMP) were identified and assessed using LC-MS/MS combined with molecular docking and in vitro approach. Three novel antioxidant peptides TGIIT, YAR and YYK were identified from MFGMPF1, among which TGIIT and YAR exhibited excellent antioxidant effects and protected dexamethasone (Dex)-induced L6 cells by enhancing mitochondrial function and biogenesis involving modulating Sirt-1/PGC-1α signaling pathway. Furthermore, YAR and TGIIT also significantly decreased expression of pro-apoptotic factors such as cyt-c, cleaved caspase-3 and caspase-9. Therefore, YAR and TGIIT, two novel antioxidant peptides, are expected to be utilized in functional food or medicine, providing an emerging role of MFGMP in maintaining anti-oxidant/oxidant status.

Five glycosylated phenolic derivatives from the bark of Ilex rotunda Thunb. and their anti-inflammatory activities.

Five new glycosylated phenolic derivatives, rotundosides A-E (1-5), and three known glycosides (6-8) were isolated from the 95% alcohol extract of the bark of Ilex rotunda. Their structures were elucidated by extensive spectroscopic analysis and comparison with the literature data. All new compounds possessed a [5-O-(E)-caffeoyl]-ß-D-apiofuranosyl-(1→6)-ß-D-glucopyranosyl group. The anti-inflammatory properties of all isolated compounds were evaluated using a modified nitric oxide (NO) production in lipopolysaccharide (LPS)-induced leukemia cells in mouse macrophage (RAW264.7) method. Compound 8, dracunculifoside H, showed significant anti-inflammatory activity in vitro.

Increase in Lactulose Content in a Hot-Alkaline-Based System through Fermentation with a Selected Lactic Acid Bacteria Strain Followed by the ß-Galactosidase Catalysis Process.

In this study, lactic acid bacteria (LAB) fermentation and ß-galactosidase catalysis methods were combined to increase the lactulose concentration and reduce the galactose and lactose content in a hot-alkaline-based system. The optimal conditions for chemical isomerization were 70 °C for 50 min for lactulose production, in which the concentration of lactulose was 31.3 ± 1.2%. Then, the selection and identification of LAB, which can utilize lactose and cannot affect lactulose content, were determined from 451 strains in the laboratory. It was found that Lactobacillus salivarius TM-2-8 had weak lactulose utilization and more robust lactose utilization. Lactobacillus rhamnosus grx.21 was weak in terms of lactulose utilization and strong in terms of galactose utilization. These two strains fermented the chemical isomerization system of lactulose to reduce the content of lactose and galactose. The results showed that the lactose concentration was 48.96 ± 2.92 g/L and the lactulose concentration was 59.73 ± 1. 8 g/L for fermentation lasting 18 h. The ß-galactosidase was used to increase the content of lactulose in the fermented system at this time. The highest concentration of 74.89 ± 1.68 g/L lactulose was obtained at an enzymatic concentration of 3 U/mL and catalyzed at 50 °C for 3 h by ß-galactosidase.

Comparison and selection of probiotic Lactobacillus from human intestinal tract and traditional fermented food in vitro via PCA, unsupervised clustering algorithm, and heat-map analysis.

Traditional fermented products and human intestines are rich sources of Lactobacillus strains which may have remarkable probiotic properties. In the present study, the probiotic properties of 40 Lactobacillus strains isolated from intestinal tracts of longevity population and traditional fermented food in China were determined, including the survival rates in simulated gastric acid and bile salt, aggregation, hydrophobicity, adhesion rate, antioxidant ability (ferric reducing antioxidant power), and antimicrobial ability. The differences between human strains and nonhuman strains were compared via t-test and principal component analysis (PCA). The significant differences were found in the survival rate at 0.3% bile salt, adhesion ability of the strains, and antioxidant ability of the fermentation broth (p < .05). The results of PCA showed that the first principal component (PC1) score of human strains was significantly higher than that of nonhuman strains (p < .01). And some probiotic Lactobacillus were selected for further application based on the unsupervised clustering algorithm, heat-map analysis, and K-means algorithm. Four strains, CS128, CS39, CS01, and CS1301, along with Lactobacillus rhamnosus GG (LGG) were divided into cluster I. The four strains, all isolated from human tracts, have been selected. Thus, human Lactobacillus has better probiotic potential and application prospects than strains from the nonhuman source. PCA, the unsupervised clustering algorithm, and heat-map analysis can be used to analyze and select Lactobacillus visually and effectively.