In Vitro and In Silico Analysis of PTP1B Inhibitors from Cleistocalyx operculatus Leaves and Their Effect on Glucose Uptake.

As part of our ongoing research on new anti-diabetic compounds from ethnopharmacologically consumed plants, two previously undescribed lupane-type triterpenoids (1 and 2) with dicarboxylic groups, an undescribed nor-taraxastane-type triterpenoid (3), and 14 known compounds (4-17) were isolated from the leaves of Cleistocalyx operculatus. Extensive spectroscopic analysis (IR, HRESIMS, 1D, and 2D NMR) was used for structure elucidation, while the known compounds were compared to reference data reported in the scientific literature. All the isolates (1-17) were evaluated for their inhibitory effects on the protein tyrosine phosphatase 1B (PTP1B) enzyme. Compounds 6, 9, and 17 showed strong PTP1B inhibitory activities. The mechanism of PTP1B inhibition was studied through enzyme kinetic experiments. A non-competitive mechanism of inhibition was determined using Lineweaver-Burk plots for compounds 6, 9, and 17. Additionally, Dixon plots were employed to determine the inhibition constant. Further insights were gained through a structure-activity relationship study and molecular docking analysis of isolated compounds with the PTP1B crystal structure. Moreover, all isolates (1-17) were tested for their stimulatory effects on the uptake of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose (2-NBDG) in differentiated 3T3-L1 adipocyte cells. Compounds 6, 13, and 17 exhibited strong glucose absorption stimulation activity in a dose-dependent manner.

Is 10 cm ileal resection sufficient in locally advanced caecal cancer surgery?

BACKGROUND: There is no consensus as to how much ileal resection is sufficient when performing a right hemicolectomy for right colon cancers. Locally advanced caecal cancer has the highest incidence of peri-ileal lymph node metastasis. Therefore, this study investigated whether the 10 cm ileum resection suggested by the Japanese Society for Cancer of the Colon and Rectum is oncologically safe in stage II and III caecal cancer. METHODS: The prospectively collected medical records of stage II and III caecal cancer patients who underwent a right hemicolectomy with at least D2 lymph node dissection were reviewed retrospectively. The patients were divided into two groups according to the length of proximal ileal resected: group 1 (≤10 cm) and group 2 (>10 cm). Factors contributing to the 5-year overall survival (OS) were analysed. RESULTS: The study enrolled 89 patients with pathological stage II or III caecal cancer. The >10 cm group tended to be younger (P = 0.0938) with higher pathological N stages (P = 0.0899) than the ≤10 cm group. The 5-year OS did not differ between the two groups. No significant difference was found between the two groups according to stage. Age (HR = 1.06, 95% CI = 1.02-1.10, P = 0.0069) and N2 stage (HR = 5.38, 95% CI = 1.90-15.28, P = 0.0016) were significantly associated with OS in both uni- and multivariate analyses. CONCLUSIONS: There was no OS benefit to resecting >10 cm of ileum in either stage II or III caecal cancer patients. Hence, we suggest that the '10 cm rule' is sufficient for stage II and III caecal cancer patients.

Chemical constituents with senolytic activity from the stems of Limacia scandens.

While screening senotherapeutics from natural products, seven undescribed chemicals, two syringylglycerol derivatives, two cyclopeptides, one tigliane analogue, and two chromone derivatives, as well as six known compounds were isolated from the stems of Limacia scandens. The structures of compounds were elucidated through spectroscopic data analysis, including 1D and 2D NMR, HRESIMS, and CD data. All compounds were tested in replicative senescent human dermal fibroblasts (HDFs) to determine their potential as senotherapeutic agents to specifically target senescent cells. One tigliane and two chromones derivatives showed senolytic activity, indicating that senescent cells were selectively removed. Especially, 2-{2-[(3'-O-ß-d-glucopyranosyl)phenyl]ethyl}chromone is expected to be a potential senotherapeutics by inducing HDF death, inhibiting the activity of senescence-associated ß-galactosidase (SA-ß-gal) and expressing senescence-associated secretory phenotype (SASP) factors.

Emodin modulates gut microbial community and triggers intestinal immunity.

BACKGROUND: The gut microbiota (GM) plays an important role in human health and is being investigated as a possible target for new therapies. Although there are many studies showing that emodin can improve host health, emodin-GM studies are scarce. Here, the effects of emodin on the GM were investigated in vitro and in vivo. RESULTS: In vitro single bacteria cultivation showed that emodin stimulated the growth of beneficial bacteria Akkermansia, Clostridium, Roseburia, and Ruminococcus but inhibited major gut enterotypes (Bacteroides and Prevotella). Microbial community analysis from a synthetic gut microbiome model through co-culture indicated the consistent GM change by emodin. Interestingly, emodin stimulated Clostridium and Ruminococcus (which are related to Roseburia and Faecalibacterium) in a mice experiment and induced anti-inflammatory immune cells, which may correlate with its impact on specific gut bacteria. CONCLUSION: Emodin (i) showed similar GM changes in monoculture, co-culture, and in an in vivo mice experiment and (ii) simulated regulatory T-cell immune responses in vivo. This suggest that emodin may be used to modulate the GM and improve health. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Insulin-mimetic activity of 23-glycosyl oleanane triterpenoids isolated from Gymnema latifolium.

Chemical investigation of the plant Gymnema latifolium led to the isolation of seven undescribed 23-glycosyl oleanane triterpenoids, gymlatinosides GLF1-GLF7, and two known compounds, gymnemosides D and E. The structures of the isolated compounds were elucidated using diverse spectroscopic methods. The extract of G. latifolium and all isolated compounds significantly enhanced 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) uptake into 3T3-L1 adipocytes at 20 µM. Among them, gymlatinosides GLF2 and gymlatinosides GLF4 showed particularly potent stimulatory effects on glucose uptake in a dose-dependent manner. Further investigation revealed that gymlatinosides GLF2 at 20 µM upregulated the expression of phosphorylated AMPK (p-AMPK). The results suggested that gymlatinosides GLF2 may enhance glucose uptake via regulating the AMPK signaling pathway.

Potent and Selective Inhibition of CYP1A2 Enzyme by Obtusifolin and Its Chemopreventive Effects.

Obtusifolin, a major anthraquinone component present in the seeds of Cassia tora, exhibits several biological activities, including the amelioration of memory impairment, prevention of breast cancer metastasis, and reduction of cartilage damage in osteoarthritis. We aimed to evaluate the inhibitory effects of obtusifolin and its analogs on CYP1A enzymes, which are responsible for activating procarcinogens, and investigate its inhibitory mechanism and chemopreventive effects. P450-selective substrates were incubated with human liver microsomes (HLMs) or recombinant CYP1A1 and CYP1A2 in the presence of obtusifolin and its four analogs. After incubation, the samples were analyzed using liquid chromatography-tandem mass spectrometry. Molecular docking simulations were performed using the crystal structure of CYP1A2 to identify the critical interactions between anthraquinones and human CYP1A2. Obtusifolin potently and selectively inhibited CYP1A2-mediated phenacetin O-deethylation (POD) with a Ki value of 0.031 µM in a competitive inhibitory manner in HLMs, whereas it exhibited negligible inhibitory effect against other P450s (IC50 > 28.6 µM). Obtusifolin also inhibited CYP1A1- and CYP1A2-mediated POD and ethoxyresorufin O-deethylation with IC50 values of <0.57 µM when using recombinant enzymes. Our molecular docking models suggested that the high CYP1A2 inhibitory activity of obtusifolin may be attributed to the combination of hydrophobic interactions and hydrogen bonding. This is the first report of selective and potent inhibitory effects of obtusifolin against CYP1A, indicating their potential chemopreventive effects.

Benzylisoquinoline Alkaloids from the Stems of Limacia scandens and Their Potential as Autophagy Inhibitors.

Limacia scandens is traditionally used to treat depression and affective disorders in Malaysia. The chemical compositions have been reported to include bisbenzylisoquinoline and aporphine-type alkaloids in the genus Limacia Lour., but studies on the components of L. scandens have rarely been reported. Therefore, this study was conducted to determine new benzylisoquinoline alkaloid derivatives with autophagy regulation activity from this plant. Bioactivity-guided isolation was applied to various column chromatography methods using RP-18, Sephadex LH-20 open column chromatography, and preparative HPLC. The chemical structures of the isolated compounds were elucidated through spectroscopic data analysis, including NMR, HR-ESI-MS, and ECD data. In addition, isolated compounds were tested for autophagy-regulating activity in HEK293 cells expressing GFP-L3. Three new dimeric benzylisoquinoline alkaloids (1-3), one new 4-hydroxybenzoic acid-conjugated benzylisoquinoline alkaloid (4), and six known compounds (5-10) were isolated from the stems of L. scandens. All compounds (1-10) were screened for autophagy regulation in HEK293 cells stably expressing the GFP-LC3 plasmid. Among the isolated compounds, 1, 2, and 4 showed autophagic regulation activity that blocked the process of combining autophagosomes and lysosomes. They also inhibit the protein degradation process from the autolysosome as inhibitors of autophagy. Novel benzylisoquinoline alkaloids from L. scandens showed potent potency for the inhibition of autophagic flux. This study provides potential candidates for developing natural autophagy inhibitors for disease prevention and treatment.

Schisandrin C improves leaky gut conditions in intestinal cell monolayer, organoid, and nematode models by increasing tight junction protein expression.

BACKGROUND: Leaky gut symptoms and inflammatory bowel disease (IBD) are associated with damaged intestinal mucosa, intestinal permeability dysfunction by epithelial cell cytoskeleton contraction, disrupted intercellular tight junction (TJ) protein expression, and abnormal immune responses and are intractable diseases. PURPOSE: We evaluated the effects of schisandrin C, a dibenzocyclooctadiene lignan from Schisandra chinensis, on intestinal inflammation and permeability dysfunction in gut mimetic systems: cultured intestinal cells, intestinal organoids, and a Caenorhabditis elegans model. METHODS: Schisandrin C was selected from 9 lignan compounds from S. chinensis based on its anti-inflammatory effects in HT-29 human intestinal cells. IL-1ß and Pseudomonas aeruginosa supernatants were used to disrupt intestinal barrier formation in vitro and in C. elegans, respectively. The effects of schisandrin C on transepithelial electrical resistance (TEER) and intestinal permeability were evaluated in intestinal cell monolayers, and its effect on intestinal permeability dysfunction was tested in mouse intestinal organoids and C. elegans by measuring fluorescein isothiocyanate (FITC)-dextran efflux. The effect of schisandrin C on TJ protein expression was investigated by western blotting and fluorescence microscopy. The signaling pathway underlying these effects was also elucidated. RESULTS: Schisandrin C ameliorated intestinal permeability dysfunction in three IBD model systems and enhanced epithelial barrier formation via upregulation of ZO-1 and occludin in intestinal cell monolayers and intestinal organoids. In Caco-2 cells, schisandrin C restored IL-1ß-mediated increases in MLCK and p-MLC expression, in turn blocking cytoskeletal contraction and subsequent intestinal permeabilization. Schisandrin C inhibited NF-ĸB and p38 MAPK signaling, which regulates MLCK expression and structural reorganization of the TJ complex in Caco-2 cells. Schisandrin C significantly improved abnormal FITC-dextran permeabilization in both intestinal organoids and C. elegans. CONCLUSION: Schisandrin C significantly improves abnormal intestinal permeability and regulates the expression of TJ proteins, long MLCK, p-MLC, and inflammation-related proteins, which are closely related to leaky gut symptoms and IBD development. Therefore, schisandrin C is a candidate to treat leaky gut symptoms and IBDs.

Plant Response to Cold Stress: Cold Stress Changes Antioxidant Metabolism in Heading Type Kimchi Cabbage (Brassica rapa L. ssp. Pekinensis).

Cold stress is known as the important yield-limiting factor of heading type Kimchi cabbage (HtKc, Brassica rapa L. ssp. pekinensis), which is an economically important crop worldwide. However, the biochemical and molecular responses to cold stress in HtKc are largely unknown. In this study, we conducted transcriptome analyses on HtKc grown under normal versus cold conditions to investigate the molecular mechanism underlying HtKc responses to cold stress. A total of 2131 genes (936 up-regulated and 1195 down-regulated) were identified as differentially expressed genes and were significantly annotated in the category of "response to stimulus". In addition, cold stress caused the accumulation of polyphenolic compounds, including p-coumaric, ferulic, and sinapic acids, in HtKc by inducing the phenylpropanoid pathway. The results of the chemical-based antioxidant assay indicated that the cold-induced polyphenolic compounds improved the free-radical scavenging activity and antioxidant capacity, suggesting that the phenylpropanoid pathway induced by cold stress contributes to resistance to cold-induced reactive oxygen species in HtKc. Taken together, our results will serve as an important base to improve the cold tolerance in plants via enhancing the antioxidant machinery.

Triterpenoid saponins from the leaves and stems of Pericampylus glaucus and their insulin mimetic activities.

During an attempt to discover insulin mimetics, thirteen new triterpenoid saponins (1-13), including three phytolaccagenic acids (1, 2, and 12) and ten serjanic acids (3-11 and 13), as aglycones were isolated from a 70% ethanol extract of leaves and stems from Pericampylus glaucus. The chemical structures of compounds 1-13 were determined through spectroscopic data analysis, including NMR, IR, and HRESIMS. All isolated compounds (1-13) were evaluated using 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-d-glucose (2-NBDG) as a fluorescent-tagged glucose probe to determine their stimulatory effects on glucose uptake in differentiated 3 T3-L1 adipocyte cells. Consequently, four compounds (4, 7, 11, and 12) exhibited stimulatory effects on glucose uptake.