The relationship between attention networks and individual differences in visual mental imagery vividness - An EEG study.

Previous research has established a strong link between attention and visual mental imagery, but it's remained uncertain whether attention networks influence individual differences in the vividness of visual mental imagery. In our study, we examined 140 participants, assessing the vividness of imagery using the Vividness of Visual Imagery Questionnaire in both eyes-open and eyes-closed conditions. We employed the Attention Network Test, coupled with EEG recording, to characterize three attention sub-networks: alerting, orienting, and executive control. To pinpoint the specific attentional networks associated with the vividness of visual mental imagery, we utilized latent profile analysis to categorize participants into distinct subgroups. Additionally, we constructed a regression mixture model to explore how attention networks predict different latent categories of visual imagery vividness. Our findings revealed that the efficiency of the alerting network, as indicated by the N1 component, demonstrated a positive correlation with the vividness of visual imagery. This electrophysiological evidence underscores the role of the alerting network in shaping individual differences in the vividness of visual mental imagery.

Artemongolides A-F, undescribed sesquiterpenoid dimers from Artemisia mongolica and their antihepatic fibrosis activities.

Artemongolides A-E (1-5), an unusual class of diseco-guaianolides featuring a rare fused 7-methylbicyclo[2.2.1]-2-ene-7-heptanol ring system, and artemongolide F (6), the first example of [4 + 2] Diels-Alder type adducts presumably incorporating a chain farnesane sesquiterpene and a guaianolide diene, were isolated from the whole plant of Artemisia mongolica. Their structures were elucidated based on the spectroscopic analyses of UV, IR, MS, and 1D and 2D NMR spectra. The absolute configurations of artemongolides A (1) and F (6) were determined by single-crystal X-ray crystallography, and those of artemongolides B-E (2-5) were established by ECD calculations. Cytotoxicity evaluation suggested that compound 1 exhibited activity against HSC-LX2 cells with an IC50 value of 165.0 µM, equivalent to that of the positive control silybin (IC50, 146.4 µM). Preliminary mechanism studies revealed that compound 1 could inhibit the deposition of human collagen type I (Col I), human hyaluronic acid (HA), and human laminin (HL) with IC50 values of 123.8, 160.4, and 139.20 µM.

Artemleucolides A-L, eudesmane-type sesquiterpenoids from Artemisia leucophylla and their antihepatoma cytotoxicity.

Twelve undescribed and 13 known eudesmane-type sesquiterpenoids were obtained from Artemisia leucophylla, and structurally elucidated based on comprehensive analyses of spectral data, including HRESIMS, IR, 1D and 2D NMR, and ECD calculation. The absolute configuration of compound 1 was determined by a single X-ray single crystal diffraction. Chemically, compounds 1-5 featured unprecedented 1,2-seco-1-nor-eudesmane-type skeleton with a cis-fused 6/5 bicyclic system. Antihepatoma evaluation against three human hepatoma cell lines (HepG2, Huh7, and SK-Hep-1) for all compounds demonstrated that compound 7 displayed the most active cytotoxicity with IC50 values of 35.1, 35.0, and 32.7 µΜ.

Comparison of 10 and 14 days of antofloxacin-based versus 14 days of clarithromycin-based bismuth quadruple therapy for Helicobacter pylori eradication: A randomized trial.

OBJECTIVE: Our team previously reported the use of antofloxacin-based bismuth quadruple therapy for the eradication of Helicobacter pylori (H. pylori). This study aimed to compare the efficacy and safety of 10 and 14 days of antofloxacin-based versus 14 days of clarithromycin-based bismuth quadruple therapy in the first-line treatment for H. pylori infection. METHODS: 1174 patients with H. pylori infection were randomized into three groups: 10-days and 14-days antofloxacin (ANT10 and ANT14) groups who received 10 and 14 days of antofloxacin-based bismuth quadruple therapy (colloidal bismuth pectin 200 mg t.i.d., esomeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and antofloxacin 200 mg q.d.), 14-days clarithromycin (CLA14) group who received 14 days of clarithromycin-based bismuth quadruple therapy (colloidal bismuth pectin 200 mg t.i.d., esomeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and clarithromycin 500 mg b.i.d.). Eradication rate, antibiotic resistance and adverse events were analyzed. RESULTS: The intention-to-treat (ITT) and per-protocol (PP) analyses have showed statistically different eradication rates between ANT14 group and ANT10 group (ITT p = 0.001; PP p < 0.001), but no statistical difference between ANT10 group and CLA14 group (ITT p = 0.340; PP p = 0.092). Treatment regimen, drug resistance and therapy duration were important clinical factors related to H. pylori eradication rates in multivariate logistic analysis. Longer durations had significantly higher eradication rates in patients with antibiotic-resistant strains or antibiotic-susceptible strains. The incidences of nausea and bitter taste were significantly higher in CLA group compared with ANT group (p = 0.002 for nausea; p = 0.002 for bitter taste). The ANT10 and ANT14 group had similar adverse event rates of gastrointestinal reactions. CONCLUSION: The study showed that the H. pylori eradication rate with ANT14 therapy was higher than that with ANT10 and CLA14 therapy without significantly increasing the rates of adverse event. 14 days of antofloxacin-based bismuth quadruple therapy may be a more effective way as the first-line treatment for H. pylori infection.

Effects of auricular acupuncture stimulation on healthy adults' upper limb motor-evoked potentials: A randomized, crossover, double-blind study.

Objective: The aim of this study was to determine whether auricular acupuncture has neuromodulatory effects on the motor cortex of healthy adults. Methods: Fourteen healthy subjects received a real auricular acupuncture stimulation (SF1) session and a sham acupuncture stimulation session. The interval between the two types of stimulation was more than 24 h. A finger dexterity test (taping score and taping speed by using ipad) was assessed, and motor-evoked potentials (MEP) were assessed before and after each stimulation. Results: Before the treatment, there were no significant differences in MEP amplitude, tapping score, or tapping speed (P > 0.05) between the real and sham stimulation conditions. After the treatment, the MEP amplitude, tapping score, and tapping speed in the real stimulation condition increased significantly compared to the pre-stimulation measurements and were significantly higher than those in the sham stimulation condition (P < 0.01). In the sham stimulation condition, the MEP amplitude, tapping score, and tapping speed decreased significantly compared to the pre-stimulation measurements (P < 0.05). Conclusion: Acupuncture of auricular points can modulate the excitability of the motor cortex area of controlling the upper limbs. Clinical trial registration: [http://www.chictr.org.cn/index.aspx], identifier [ChiCTR2100051608].

Artemzhongdianolides A1-A21, antihepatic fibrosis guaiane-type sesquiterpenoid dimers from Artemisia zhongdianensis.

In the search for new antihepatic fibrosis candidates, it was observed that the EtOH extract of Artemisia zhongdianensis and EtOAc fraction had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with the inhibitory ratios of 85.7 % and 83.9 % at 400 µg/mL. 21 new guaianolide dimers, artemzhongdianolides A1 - A21 (1-21) were isolated from the active fractions under the guidance of bioassay, and elucidated by spectral analyses (HRESIMS, 1D and 2D NMR, IR, ECD). The absolute stereochemistry of compounds 1, 13, and 14 was determined by single-crystal X-ray diffraction analyses. Cytotoxicity evaluation suggested that nine compounds exhibited activity against HSC-LX2 with IC50 values ranging from 14.0 to 95.2 µM. Of them, compounds 2, 6, and 13 displayed significant cytotoxicity against HSC-LX2 with IC50 values of 22.1, 24.3 and 14.0 µM, which were 6 to 10 times more active than the positive drug silybin (IC50, 148.6 µM). Preliminary mechanism study revealed that compounds 2, 6, and 13 could markedly inhibited the deposition of human collagen type Ⅰ (Col Ⅰ), human hyaluronic acid (HA), and human laminin (HL) with IC50 values of 37.9, 54.8, and 28.0 µM (Col Ⅰ), 29.5, 25.3, and 42.9 µM (HL), 31.2, 94.6, and 12.4 µM (HA), which were 1.5 to 13-fold more potent than silybin.

Serum vitamin D status among healthy children in Hainan, South China: a multi-center analysis of 10,262 children.

Background: There are limited data regarding the prevalence and risk factors relating to vitamin D deficiency (VDD) in children of Hainan, a tropical city with abundant sunlight in China. To gather and analyze the serum VD levels of healthy children in Hainan, so as to understand their VD nutritional status and improve the representative data of VD nutritional status in south China. Methods: Children who presented to the outpatient clinic for physical examination at 4 hospitals in the Hainan Province from 2012 to 2020 were enrolled in this study. The serum 25-hydroxyvitamin D (25-OHD) levels was analyzed. 25-OHD levels <50 nmol/L is considered VDD, 50-75 nmol/L is vitamin D insufficiency (VDI), and ≥75 nmol/L is VD sufficient (VDS). Results: The average serum 25-OHD level was 94.63±49.99 nmol/L [95% confidence interval (CI): 93.67-95.60]. VDD was detected in 13.98% of participants (1,435 cases), VDI was detected in 30.60% of participants (3,140 cases), and 55.42% presented with VDS (5,687 cases). The average 25-OHD level of boys was significantly higher than that of girls (t=3.67, P<0.001). The average serum 25-OHD levels in the following age groups 0-1, 1-3, 3-7, 7-14, and 14-18 years were 105.92±57.39, 100.55±53.22, 86.35±39.19, 73.61±34.21, and 54.97±19.19 nmol/L, respectively. These results suggested that with an increase in age, the 25-OHD levels decreased. The average 25-OHD levels of children with a body mass index (BMI) <85th percentile were significantly higher than that of children in the overweight and obese group (F=7.393, P=0.001). Conclusions: A certain proportion of all age groups showed vitamin D deficiency and insufficiency in Hainan. A formal recommendation for vitamin D supplementation should be considered, especially in autumn and winter seasons for children over 7 years old, and in those with BMI ≥85th percentile or BMI ≥95th percentile.

Artemidubolides A-T, cytotoxic unreported guaiane-type sesquiterpenoid dimers against three hepatoma cell lines from Artemisia dubia.

A random bioassay revealed that the EtOH extract and EtOAc fraction of Artemisia dubia Wall. (Asteraceae) exhibited cytotoxic activity against HepG2 cells with inhibitory ratios of 57.1% and 84.2% at a concentration of 100.0 µg/mL. Bio-guided isolation combined by LC-MS-IT-TOF analyses of the active fractions led to the isolation of 20 previously undescribed guaiane-type sesquiterpenoid dimers named artemidubolides A-T (1-20). Their structures and the absolute configurations were determined by comprehensive spectral analyses, comparison of the experimental and calculated ECD spectra, and seven compounds (artemidubolides A, B, D, F, K, O and R) were confirmed unequivocally by single crystal X-ray diffraction analysis. Structurally, artemidubolides A-Q were [4 + 2] Diels-Alder adducts of two monomeric guaianolides, and artemidubolides R-T were linked though an ester bond. All the isolated compounds were evaluated for their hepatomatic cytotoxicity against HepG2, Huh7, and SK-Hep-1 cell lines to demonstrate that 18 compounds exhibited obvious cytotoxicity against three tested hepatoma cell lines with IC50 values in the range of 5.4-87.6 µM. Importantly, artemidubolides B, D, and M exhibited hepatoma cytotoxicity with IC50 values of 5.4, 5.7, and 9.7 (HepG2), 8.2, 4.3, and 12.2 (Huh7), and 13.4, 8.4, and 12.9 µM (SK-Hep-1), respectively. Mechanism investigation in HepG2 cells suggested the most active artemidubolide D dose-dependently inhibited cell migration and invasion, induced G1/M cell cycle arrest by down-regulating proteins CDK4, CDK6 and CyclinD1 and up-regulating the level of protein P21; and induced apoptosis by down-regulated of PARP-1 and BCL-2 expression and up-regulating Bax and cleaved PARP-1 levels.

Norlignans as potent GLP-1 secretagogues from the fruits of Amomum villosum.

The dried fruit of Amomum villosum (Amomi Fructus) is an important spices and traditional Chinese medicine. In this study, the EtOH extract of Amomi Fructus was revealed with hypoglycemic effects on db/db mice by increasing plasma insulin levels. After extracted with EtOAc, the EtOAc fraction showed increased activity in stimulating glucagon-like peptide-1 (GLP-1) secretion compared with the EtOH extract. In order to clarify the antidiabetic constituents, four undescribed norlignans, amovillosumins A‒D, were isolated from the EtOAc fraction, and the subsequent chiral resolution yielded three pairs of enantiomers. Their structures were determined by extensive spectroscopic data (1D and 2D NMR, HRESIMS, IR, UV and [α]D) and ECD calculations. Amovillosumins A and B significantly stimulated GLP-1 secretion by 375.1% and 222.7% at 25.0 µM, and 166.9% and 62.7% at 12.5 µM, representing a new type of GLP-1 secretagogues.

New diarylheptanoid dimers as GLP-1 secretagogues and multiple-enzyme inhibitors from Alpinia katsumadai.

Ten new diarylheptanoid dimers, katsumadainols C1 - C10 (1-10), were isolated from the seeds of Alpinia katsumada and elucidated by extensive spectroscopic methods, ECD calculations, and single-crystal X-ray diffraction. Their antidiabetic effects were evaluated by the stimulation of GLP-1 secretion in STC-1 cells and inhibition against four diabetes-related enzymes, GPa, α-glucosidase, PTP1B, and DPP4. Compounds 1-5 and 7-10 significantly stimulated GLP-1 secretion by 267.5-433.1% (25.0 µM) and 117.8-348.2% (12.5 µM). Compounds 1-4 exhibited significant inhibition on GPa with IC50 values of 18.0-31.3 µM; compounds 1-5 showed obvious inhibition on α-glucosidase with IC50 values of 6.9-18.2 µM; compounds 1-5 and 10 possessed PTP1B inhibitory activity with IC50 values ranging from 35.5 to 80.1 µM. This investigation first disclosed compounds 1-4 as intriguing GLP-1 secretagogues and GPa, α-glucosidase, and PTP1B inhibitors, which provided valuable clues for searching multiple-target antidiabetic candidates from Zingiberaceae plants.

Artemicapillasins A-N, cytotoxic coumaric acid analogues against hepatic stellate cell LX2 from Artemisia capillaris (Yin-Chen).

Under the guidance of bioassay against HSC-LX2, the EtOH extract and the EtOAc fraction of Artemisia capillaris (Yin-Chen) exhibited cytotoxic activity against HSC-LX2 with inhibitory ratios of 39.7% and 68.7% at the concentration of 400.0 µg/mL. Bioassay-guided investigation of Fr. D (the active fraction) yielded 14 new coumaric acid analogues, artemicapillasins A-N (1-14). The structures of the isolates were elucidated by spectroscopic analyses involving UV, IR, MS, 1D and 2D NMR spectra and ECD calculations. Cytotoxic activity against HSC-LX2 cells of these isolates was performed to reveal that 12 compounds demonstrated cytotoxicity with inhibitory ratios more than 50% at 400 µM. The most active artemicapillasin B (2) gave an IC50 value of 24.5 µM, which was about 7 times more toxic than the positive drug silybin (IC50, 162.3 µM). Importantly, artemicapillasin B (2) showed significant inhibition on the deposition of human collagen type I (Col I), human laminin (HL) and human hyaluronic acid (HA) with IC50 values of 11.0, 14.4 and 13.8 µM, which was about 7, 11 and 5 times more active than silybin. Artemicapillasin B (2) as an interesting antihepatic fibrosis candidate is worth in-depth study.

Artematrovirenins A-P, guaiane-type sesquiterpenoids with cytotoxicities against two hepatoma cell lines from Artemisia atrovirens.

Random screening revealed that the EtOH extract of Artemisia atrovirens showed significant cytotoxicity against two human hepatoma cell lines (HepG2 and Huh7) with the inhibitory ratio of 98.9% and 99.7% at the concentration of 100 µg/mL. Further bioactivity-guided isolation of active fraction led to 16 new guaiane-type sesquiterpenoids, artematrovirenins A-P (1-16). Their structures were elucidated by extensive spectroscopic data. The absolute stereochemistry of compounds 1 and 14 was determined by single-crystal X-ray diffraction analyses. Pharmacological evaluation suggested that five compounds (3, 5, 8, 10, and 15) exhibited cytotoxicity, compounds 3 and 5 displayed cytotoxicity against HepG2 cell line with an IC50 values of 8.0 and 16.0 µM, as well as against Huh7 cell line with values of 18.2 and 32.2 µM.

Artatrovirenols A and B: Two Cagelike Sesquiterpenoids from Artemisia atrovirens.

Artatrovirenols A and B (1 and 2), two novel cagelike sesquiterpenoids, possess a unique 5/5/6/5/5-pentacyclic and a 5/5/6/5-tetracyclic system with an unprecedented tetracyclo[5.3.1.1.4,1101,5]dodecane scaffold from Artemisia atrovirens. The structures of compounds 1 and 2 including their absolute stereochemistry were elucidated through extensive spectroscopic analyses, X-ray crystallography, and quantum chemical calculations. Plausible biosynthetic pathways for the new isolates were proposed from the naturally occurring arglabin (3) via the key intramolecular Diels-Alder cycloaddition. Compound 1 showed cytotoxicity against three human hepatoma cell lines (HepG2, SMMC-7721, and Huh7) with half maximal inhibitory concentration values of 123.8, 44.0, and 142.6 µΜ, respectively.

Artemyrianolides A-S, Cytotoxic Sesquiterpenoids from Artemisia myriantha.

Random screening suggested that the EtOH extract of Artemisia myriantha (Asteraceae) and its EtOAc fraction had cytotoxicity against HepG2 cells with inhibitory ratios of 30.6% and 53.5% at 50.0 µg/mL. Bioassay-guided isolation of the most active fractions (Fr. C and Fr. D) afforded 19 new sesquiterpenolides, artemyrianolides A-S (1-19), involving 13 germacranolides (1-13), four guaianolides (14-17), and two eudesmanolides (18 and 19), together with 16 known sesquiterpenoids (20-35). The new compounds were characterized by physical data analyses (HRESIMS, IR, 1D and 2D NMR, ECD), and the absolute configurations of compounds 1, 2, and 11 were determined by X-ray crystallography. Structurally, compounds 2 and 11-13 maintain an uncommon cis-fused 10/5 bicyclic system and compound 12 possesses an unusual (7S) configuration. Twenty of the compounds exhibited cytotoxicity against HepG2, Huh7, and SMMC-7721 cell lines. Compound 9 showed cytotoxic activity on both HepG2 and Huh7 cells with IC50 values of 8.6 and 8.8 µM, and compounds 8 and 33 showed cytotoxicity to the three human hepatoma cell lines with IC50 values of 4.9 and 7.4 µM (HepG2), 4.3 and 7.8 µM (Huh7), and 3.1 and 9.8 µM (SMMC-7721), respectively.

Cytotoxic sesquiterpenoids against hepatic stellate cell line LX2 from Artemisia lavandulaefolia.

The preliminary assay suggested that the EtOH extract of Artemisia lavandulaefolia had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with an inhibitory ratio of 94.1% at 400 µg/mL. Bioassay-guided investigation led to eleven new sesquiterpenoids, artemilavanolides C-F (1-4) and artemlavandulolides A-G (5-11), as well as thirteen known compounds (12-24). Their structures were elucidated by extensive spectroscopic data and X-ray crystallographic analysis. Cytotoxicity evaluation suggested that fourteen compounds exhibited activity against HSC-LX2; compounds 22, 23 and 24 were comparable to the positive control, silybin (IC50, 162.3 µM); compounds 6, 9 and 16 showed moderate activity with IC50 values of 109.3, 114.0 and 124.2 µM. Importantly, compounds 14, 15 and 18 displayed significant cytotoxicity against HSC-LX2 with IC50 values of 52.1, 16.5 and 21.3 µM, and inhibitory activity on the deposition of human collagen type I (Col I) and human laminin (HL) with IC50 values ranging from 7.3 to 71.6 µM and from 18.6 to 72.9 µM.

UFLC-PDA-MS/MS Profiling of Seven Uncaria Species Integrated with Melatonin/5-Hydroxytryptamine Receptors Agonistic Assay.

Uncariae Ramulus Cum Uncis (Gou-Teng), the dried hook-bearing stems of several Uncaria plants (Rubiaceae), is a well-known herbal medicine in China. The clinical application of Gou-Teng is bewildered for the morphological and chemical similarity between different species. In order to discern their chemical and biological difference, an ultra-fast liquid chromatography equipped with ion trap time-of-flight mass spectrometry (UFLC-IT/TOF-MS) combining with melatonin (MT1 and MT2) and 5-hydroxytryptamine (5-HT1A and 5-HT2C) receptors agonistic assay in vitro was conducted on seven Uncaria species. As a result, 57 compounds including 35 indole alkaloids, ten flavonoids, five triterpenoids, five chlorogenic analogues, and two other compounds were characterized based on their MS/MS patterns and UV absorptions. Specifically, cadambine-type and corynanthein-type alkaloids were exclusively present in U.rhynchophylla and U.scandens, whereas corynoxine-type alkaloids were commonly detected in all the seven Uncaria plants. Three Uncaria species, U. rhynchophylla, U. macrophylla, and U. yunnanensis showed obviously agnostic activity on four neurotransmitter receptors (MT1, MT2, 5-HT1A, and 5-HT2C). This first-time UFLCMS-IT-TOF analyses integrated with biological assay on seven Uncaria plants will provide scientific viewpoints for the clinical application of Gou-Teng.

Effect of interval between preoperative radiotherapy and surgery on clinical outcome and radiation proctitis in rectal cancer from FOWARC trial.

OBJECTIVE: The aim of this study was to evaluate the effect of the interval between CRT and surgery on radiation proctitis, the pathologic response, and postoperative morbidity. METHODS: This was a cohort study from a phase III, randomized controlled trial (FOWARC study, NCT01211210). Data were retrieved from the leading center of the trial. Patients were divided into the short-interval (≤7 weeks) group and the long-interval (>7 weeks) group. The rate of radiation proctitis, pathologic complete regression (pCR) and morbidities were calculated for each group. Multivariate analysis was used to verify the impact of interval on radiation proctitis. RESULTS: Surgery was performed in 60 patients after an interval of ≤7 weeks and in 97 patients after an interval of >7 weeks. The two groups according to interval were comparable in terms of baseline demographic and clinicotherapeutic characteristics. Radiation proctitis was identified by imaging in 9 (15.0%) patients in short-interval group and in 31 (32.0%) patients in long-interval group (P = .018). Multivariate analysis confirmed the correlation between long interval and radiation proctitis (P = .018). The long interval was significantly associated with longer median operation time compared to the short interval (P = .022). The rates of pCR and postoperative complications were not different between two groups. CONCLUSIONS: A longer interval after CRT may be associated with higher rate of radiation proctitis and longer operation time. Moreover it did not increase the rate of pCR.

Neuroprotective Effects of Ginsenoside Rg1 against Hyperphosphorylated Tau-Induced Diabetic Retinal Neurodegeneration via Activation of IRS-1/Akt/GSK3ß Signaling.

We have recently demonstrated that tau hyperphosphorylation causes diabetic synaptic neurodegeneration of retinal ganglion cells (RGCs), which might be the earliest affair during the pathogenesis of diabetic retinopathy (DR). Thus, there is a pressing need to seek therapeutic agents possessing neuroprotective effects against tau hyperphosphorylation in RGCs for arresting the progression of DR. Here, using a well-characterized diabetes model of db/db mouse, we discovered that topical ocular application of 10 mg/kg/day of ginsenoside Rg1 (GRg1), one of the major active ingredients extracted from Panax ginseng and Panax notoginseng, ameliorated hyperphosphorylated tau-triggered RGCs synaptic neurodegeneration in diabetic mice. The neuroprotective effects of GRg1 on diabetic retinae were abrogated when retinal IRS-1 or Akt was suppressed by intravitreal injection with si-IRS-1 or topically coadministered with a specific inhibitor of Akt, respectively. However, selective repression of retinal GSK3ß by intravitreal administration of si-GSK3ß rescued the neuroprotective properties of GRg1 when Akt was inactivated. Therefore, the present study showed for the first time that GRg1 can prevent hyperphosphorylated tau-induced synaptic neurodegeneration of RGCs via activation of IRS-1/Akt/GSK3ß signaling in the early phase of DR. Moreover, our data clarify the potential therapeutic significance of GRg1 for neuroprotective intervention strategies of DR.

Polybenzyls from Gastrodia elata, their agonistic effects on melatonin receptors and structure-activity relationships.

Gastrodia elata is a famous traditional Chinese herb with medicinal and edible application. In this study, nine polybenzyls (1-9), including six new ones (2-5, 7 and 9), were isolated from the EtOAc extract of G. elata. Five compounds 1, 3, 4, 6 and 8 were found to activate melatonin receptors. Especially, compound 1 showed agonistic effects on MT1 and MT2 receptors with EC50 values of 237 and 244 µM. For better understanding their structure-activity relationships (SARs), ten polybenzyl analogs were further synthesized and assayed for their activities on melatonin receptors. Preliminary SARs study suggested that two para-hydroxy groups were the key pharmacophore for maintaining activity. Molecular docking simulations verified that compound 1 could strongly interact with MT2 receptor by bonding to Phe 118, Gly 121, His 208, Try 294 and Ala 297 residues.

Antidiabetic Stilbenes from Peony Seeds with PTP1B, α-Glucosidase, and DPPIV Inhibitory Activities.

One unusual resveratrol tetramer, paeonilactiflorol (1), and 14 known compounds (2-15) were isolated from peony seeds ( Paeonia lactiflora) under the guidance of bioassay. Paeonilactiflorol (1) was determined by extensive HRESIMS, UV, IR, 1D and 2D NMR spectroscopic analyses. Most of the stilbenes showed obvious inhibition on PTP1B and α-glucosidase, superior to the monoterpene glycosides. Especially, the stilbene tetramer (1) and trimer (8) exhibited high activity inhibiting both PTP1B with IC50 values of 27.23 and 27.81 µM and α-glucosidase with IC50 values of 13.57 and 14.39 µM. Two trans-dimers (4 and 5) also showed dipeptidyl peptidase-4 (DPPIV) inhibitory activity (55.35% and 61.26%, 500 µM) in addition to PTP1B and α-glucosidase. Enzyme kinetic study indicated that the types of inhibition on PTP1B were noncompetitive for 3 and 5 and mixed for 8 and 10. Quantitative analysis suggested that the stilbene trimers 8 (23.17 ± 0.36 mg/g) and 10 (15.24 ± 0.25 mg/g) were the main contents in peony seeds and should be responsible for the antidiabetic effects. This investigation supports the therapeutic potential of peony seeds in the treatment of diabetes with stilbenes as the active constituents.