Development and Validation of UPLC-MS/MS Analysis for Sphingolipids Isolated from Velvet Antlers of Cervus elaphus

Deer velvet antlers, known as tonics, have created a large market as dietary supplements and have been consumed worldwide. Despite the high consumption of velvet antlers as dietary supplements, analytical methods for their identification and standardization remain limited. Quantitative analysis for gangliosides, considered quality indexes for velvet antlers, was developed to indirectly analyze the sialic acid obtained from chemical degradation. Owing to the complex and time-consuming chemical derivatization of gangliosides, a simple and rapid quality evaluation method for velvet antlers must be developed. For the first time, this study reports the isolation and structural elucidation of two new sphingomyelins (1 and 2), two known sphingomyelins (3 and 4), and four ceramides (5-8) as chemical markers from the velvet antlers of Cervus elaphus. To expedite and simplify the quality control of velvet antlers, advanced quantitative analysis of sphingolipids has been developed using ultra-performance liquid chromatography-mass spectroscopy.

Eupatolide, isolated from Liriodendron tulipifera, sensitizes TNF-mediated dual modes of apoptosis and necroptosis by disrupting RIPK1 ubiquitination

Ubiquitination of RIPK1 plays an essential role in the recruitment of the IKK complex, an upstream component of pro-survival NF-κB. It also limits TNF-induced programmed cell death by inhibiting the spatial transition from TNFR1-associated complex-I to RIPK1-dependent death-inducing complex-II or necrosome. Thus, the targeted disruption of RIPK1 ubiquitination, which induces RIPK1-dependent cell death, has proven to be a useful strategy for improving the therapeutic efficacy of TNF. In this study, we found that eupatolide, isolated from Liriodendron tulipifera, is a potent activator of the cytotoxic potential of RIPK1 by disrupting the ubiquitination of RIPK1 upon TNFR1 ligation. Analysis of events upstream of NF-κB signaling revealed that eupatolide inhibited IKKβ-mediated NF-κB activation while having no effect on IKKα-mediated non-canonical NF-κB activation. Pretreatment with eupatolide drastically interfered with RIPK1 recruitment to the TNFR1 complex-I by disrupting RIPK1 ubiquitination. Moreover, eupatolide was sufficient to upregulate the activation of RIPK1, facilitating the TNF-mediated dual modes of apoptosis and necroptosis. Thus, we propose a novel mechanism by which eupatolide activates the cytotoxic potential of RIPK1 at the TNFR1 level and provides a promising anti-cancer therapeutic approach to overcome TNF resistance.

Angular dihydropyranocoumarins from the flowers of Peucedanum japonicum and their aldo-keto reductase inhibitory activities

Twenty-one angular dihydropyranocoumarins and a linear furanocoumarin, including four previously undescribed compounds (1-4), were isolated from the flowers of Peucedanum japonicum (Umbelliferae). The structures of 1-4, along with their absolute stereochemistry, were determined to be (3'S,4'S)-3'-O-propanoyl-4'-O-(3‴-methyl-2‴-butenoyl)khellactone (1), (3'S,4'S)-3'-O-propanoyl-4'-O-(2‴-methyl-2‴Z-butenoyl)khellactone (2), (3'S,4'S)-3'-O-propanoyl-4'-O-(2‴-methylbutanoyl)khellactone (3), and (3'S,4'S)-3'-O-(2″-methylpropanoyl)-4'-O-(3‴-methyl-2‴-butenoyl)khellactone (4) using one- and two-dimensional nuclear magnetic resonance, high-resolution electrospray ionization mass spectroscopy, and electronic circular dichroism spectroscopy. In addition, the absolute configuration of the three angular dihydropyranocoumarins (5-7) was determined for the first time in this study. Among the previously reported compounds isolated in this study, 8 and 9 were isolated for the first time from the genus Peucedanum, whereas 10 and 11 were previously unreported and had not been isolated from P. japonicum to date. Furthermore, all isolated compounds were evaluated for their aldo-keto reductase 1C1 inhibitory activities on A549 human non-small-cell lung cancer cells. Compounds 10 and 12 exhibited substantial AKR1C1 inhibitory activities with IC50 values of 35.8 ± 0.9 and 44.2 ± 1.5 μM, respectively.

Changes in Disc Height as a Prognostic Factor in Patients Undergoing Microscopic Discectomy

OBJECTIVE

Some patients with disc herniation who underwent discectomy complain of back pain after surgery and are unsatisfied with the surgical results. This study aimed to evaluate the relationship between preoperative disc height (DH), postoperative DH, and pain score 12 months after surgery in patients who underwent microdiscectomy for herniated lumbar disc.

METHODS

This study enrolled patients who underwent microdiscectomy at a medical center between January 2012 and December 2020. Patients with X-ray or computed tomography and pain score assessment (visual analog scale score) prior to surgery, immediately post-op, and at 1, 6, and 12 months after surgery were included. The DH index was defined as DH/overlying vertebral width. The DH ratio was defined as the postoperative DH/preoperative DH. Simple linear regression and multivariate linear regression analyses were applied to assess the correlation between DHs and leg pain scores 12 months after surgery.

RESULTS

A total of 118 patients who underwent microdiscectomy were included. DH decreased up to 12 months after surgery. The DH ratio at 1, 6, and 12 months after discectomy showed a significant positive correlation with the pain scores at 12 months after discectomy (1 month : p=0.045, B=0.52; 6 months : p=0.008, B=0.78; 12 months : p=0.005, B=0.69). Multivariate linear regression analysis revealed that the level of surgery, sex, age, and body mass index had no significant relationship with back pain scores after 12 months.

CONCLUSION

In patients who underwent microdiscectomy, the DH ratios at 1, 6, and 12 months after surgery were prognostic factors for back pain scores at 12 months after surgery. Aggressive discectomy is recommended for lower postoperative DH ratios and Visual analog scale scores, leading to improved patient satisfaction.

Rubiarbonol B induces RIPK1-dependent necroptosis via NOX1-derived ROS production

The activation of receptor-interacting protein kinase 1 (RIPK1) by death-inducing signaling complex (DISC) formation is essential for triggering the necroptotic mode of cell death under apoptosis-deficient conditions. Thus, targeting the induction of necroptosis by modulating RIPK1 activity could be an effective strategy to bypass apoptosis resistance in certain types of cancer. In this study, we screened a series of arborinane triterpenoids purified from Rubia philippinesis and identified rubiarbonol B (Ru-B) as a potent caspase-8 activator that induces DISC-mediated apoptosis in multiple types of cancer cells. However, in RIPK3-expressing human colorectal cancer (CRC) cells, the pharmacological or genetic inhibition of caspase-8 shifted the mode of cell death by Ru-B from apoptosis to necroptosis though upregulation of RIPK1 phosphorylation. Conversely, Ru-B-induced cell death was almost completely abrogated by RIPK1 deficiency. The enhanced RIPK1 phosphorylation and necroptosis triggered by Ru-B treatment occurred independently of tumor necrosis factor receptor signaling and was mediated by the production of reactive oxygen species via NADPH oxidase 1 in CRC cells. Thus, we propose Ru-B as a novel anticancer agent that activates RIPK1-dependent cell death via ROS production, and suggest its potential as a novel necroptosis-targeting compound in apoptosis-resistant CRC.

Efficacy of Quantitative Pupillary Light Reflex for Predicting Neurological Outcomes in Patients Treated with Targeted Temperature Management after Cardiac Arrest: A Systematic Review and Meta-Analysis

Background and objectives: This study aims to evaluate the usefulness of the quantitative pupillary light reflex as a prognostic tool for neurological outcomes in post-cardiac arrest patients treated with targeted temperature management (TTM). Material and Methods: We systematically searched MEDLINE, EMBASE, and the Cochrane Library (search date: 9 July 2021) for studies on post-cardiac arrest patients treated with TTM that had measured the percent constriction of pupillary light reflex (%PLR) with quantitative pupillometry as well as assessed the neurological outcome. For an assessment of the methodological quality of the included studies, two authors utilized the prognosis study tool independently. Results: A total of 618 patients from four studies were included in this study. Standardized mean differences (SMDs) were calculated to compare patients with good or poor neurological outcomes. A higher %PLR measured at 0–24 h after hospital admission was related to good neurological outcomes at 3 months in post-cardiac arrest patients treated with TTM (SMD 0.87; 95% confidence interval 0.70–1.05; I² = 0%). A higher %PLR amplitude measured at 24–48 h after hospital admission was also associated with a good neurological outcome at 3 months in post-cardiac arrest patients treated with TTM, but with high heterogeneity (standardized mean difference 0.86; 95% confidence interval 0.40–1.32; I² = 70%). The evidence supporting these findings was of poor quality. For poor neurological outcome, the prognosis accuracy of %PLR was 9.19 (pooled diagnostic odds ratio, I² = 0%) and 0.75 (area under the curve). Conclusions: The present meta-analysis could not reveal that change of %PLR was an effective tool in predicting neurological outcomes for post-cardiac arrest patients treated with TTM owing to a paucity of included studies and the poor quality of the evidence.

Lucidin 3-methyl ether from Rubia philippinensis suppresses the proliferation of multiple myeloma cells through the promotion of β-catenin degradation

BACKGROUND

Constitutive accumulation of β-catenin has been frequently observed in multiple myeloma. Extracts from genus Rubia plants exhibit cytotoxic activity against several types of cancer cells; however, little is known about their chemopreventive mechanisms and bioactive metabolites.

PURPOSE

Purpose: The study aimed to identify the underlying antiproliferative mechanisms of Rubia philippinensis extract in multiple myeloma cells and the major active metabolites responsible for cytotoxic activity of R. philippinensis.

METHODS

The effects of R. philippinensis extracts and lucidin 3-methyl ether on the Wnt/β-catenin pathway were determined by cell-based reporter assay, Western blot analysis, and RT-PCR. The antiproliferative activity was evaluated by cell viability assay and apoptosis analysis in RPMI8226 and MM.1S multiple myeloma cells.

RESULTS

R. philippinensis extracts inhibited Wnt/β-catenin signaling and lucidin 3-methyl ether, an anthraquinone derivative, was identified as the major active metabolite responsible for the inhibition of Wnt/β-catenin signaling. Lucidin 3-methyl ether induced β-catenin phosphorylation at Ser33/Ser37/Thr41 residues and promoted proteasomal degradation of β-catenin via a GSK-3β-independent mechanism, thereby downregulating Wnt3a-induced β-catenin response transcription (CRT). Moreover, lucidin 3-methyl ether repressed the expression of β-catenin/T-cell factor (TCF)-dependent genes, such as cyclin D1, c-myc, and axin-2, thus inhibiting MM cell proliferation. Apoptosis was also elicited by lucidin 3-methyl ether, as indicated by the increase in the population of annexin V-FITC positive cells and caspase-3/7 activity in MM cells.

CONCLUSION

These findings indicate that R. philippinensis and its active metabolite lucidin 3-methyl ether prevent cell proliferation through the suppression of the Wnt/β-catenin pathway and exhibit potential as chemopreventive agents for the treatment of MM.

Cellular antioxidant potential and inhibition of foodborne pathogens by a sesquiterpene ilimaquinone in cold storaged ground chicken and under temperature-abuse condition

A sesquiterpene quinone, ilimaquinone, was accessed for its cellular antioxidant efficacy and possible antimicrobial mechanism of action against foodborne pathogens (Staphylococcus aureus and Escherichia coli) in vitro and in vivo. Ilimaquinone was found to be protective against H₂O₂-induced oxidative stress as validated by the reduction in the ROS levels, including increasing expression of SOD1 and SOD2 enzymes. Furthermore, ilimaquinone evoked MIC against S. aureus and E. coli within the range of 125-250 µg/mL. Ilimaquinone established its antimicrobial mode of action against both tested pathogens as evident by bacterial membrane depolarization, loss of nuclear genetic material, potassium ion, and release of extracellular ATP, as well as compromised membrane permeabilization and cellular component damage. Also, ilimaquinone showed no teratogenic effect against zebrafish, suggesting its nontoxic nature. Moreover, ilimaquinone significantly reduced the S. aureus count without affecting the sensory properties and color values of cold-storaged ground chicken meat even under temperature abuse condition.

Efficacy of 3D-Printed Titanium Mesh-Type Patient-Specific Implant for Cranioplasty

Objective

Autologous bone grafting for cranioplasty is associated with a high infection rate and bone absorption. Synthetic implant materials for cranioplasty have been developed. In this study, we evaluated the efficacy of titanium mesh-type patient-specific implants (PSIs) for patients with skull defects using the dice similarity coefficient (DSC), clinical outcomes, and artifacts caused by implants.

Methods

This retrospective study included 40 patients who underwent cranioplasty with a titanium mesh PSI at our institution. Based on preoperative and postoperative computed tomography scans, we calculated DSC and artifacts.

Results

The calculated DSC of 40 patients was 0.75, and the noise was 13.89% higher in the region of interest (ROI) near the implanted side (average, 7.64 hounsfield unit [HU]±2.62) than in the normal bone (average, 6.72 HU±2.35). However, the image signal-to-noise ratio did not significantly differ between the ROI near the implanted side (4.77±1.78) and normal bone (4.97±1.88). The patients showed no significant perioperative complications that required a secondary operation.

Conclusion

Titanium mesh-type PSIs for cranioplasty have excellent DSC values with lower artifacts and complication rates.

Configurational Assignment of a Flexible Benzo[g]isochromene Stereodiad from Rubia philippinensis and Inhibition of Soluble Epoxide Hydrolase Activity

A new benzo[g]isochromene possessing a conformationally mobile moiety was identified from Rubia philippinensis. The 2D structure was established utilizing spectrometric and spectroscopic techniques with variable temperatures. The configurational investigation of the flexible moiety was investigated utilizing contemporary NMR-combined computational tools such as DP4, direct J-DP4, and DP4 Plus. The probabilities computed from DP4 Plus analysis, featuring inclusion of an additional geometry optimization process, demonstrated more conclusive probability scores among the analyses used. The configurational assignment was also supported by compositional and molecular orbital analyses. Compound 1 inhibited soluble epoxide hydrolase (IC₅₀ = 0.6 ± 0.01 μM), an enzyme associated with cardiovascular disorders.

Isolation of Sesquiterpenoids and Steroids from the Soft Coral Sinularia brassica and Determination of Their Absolute Configuration

Two undescribed rearranged cadinane-type sesquiterpenoids (1-2), named sinulaketol A-B, together with one new chlorinated steroid (3), one new gorgosterol (4), one known sesquiterpene (5), one known dibromoditerpene (6) and two known polyhydroxylated steroids (7-8) were isolated from the soft coral Sinularia brassica. The structures of these compounds were established by extensive spectroscopic analysis, including HRESIMS, 1D, and 2D NMR spectroscopy. Their absolute configurations were also determined by the ECD calculations and DP4+ probability analysis. Antileishmanial activity of compounds 1-8 was evaluated in vitro against the amastigote forms of Leishmania donovani, in which compounds 3, 6, and 7 inhibited the growth of L. donovani by 58.7, 74.3, 54.7%, respectively, at a concentration of 50 μM. Antimicrobial effect of the isolated compounds were also evaluated against Candida albicans, Staphylococcus aureus, and Escherichia coli. Compound 6, a brominated diterpene, exhibited antimicrobial effect against S. aureus.

8-Geranylumbelliferone isolated from Paramignya trimera triggers RIPK1/RIPK3-dependent programmed cell death upon TNFR1 ligation

In tumor necrosis factor (TNF) signaling, IκB kinase (IKK) complex-mediated activation of NF-κB is a well-known protective mechanism against cell death via transcriptional induction of pro-survival genes occurring as a late checkpoint. However, recent belief holds that IKK functions as an early cell death checkpoint to suppress the death-inducing signaling complex by regulating receptor interacting protein kinase1 (RIPK1) phosphorylation. In this study, we propose that two major gernaylated 7-hydroxy coumarins, 6-geranyl-7-hydroxycoumarin (ostruthin) and 8-geranyl-7-hydroxycoumarin (8-geranylumbelliferone, 8-GU) isolated from Paramignya timera, facilitate RIPK1-dependent dual modes of apoptosis and necroptosis by targeting IKKβ upon TNF receptor1 (TNFR1) ligation. Analysis of events upstream of NF-κB revealed that 8-GU and ostruthin drastically inhibited TNF-induced IKK phosphorylation, while having no effect on TAK1 phosphorylation and TNFR1 complex-I formation. Interestingly, 8-GU did not affect the cell death induced by Fas ligand or TNF-related apoptosis-inducing ligand or that induced by DNA-damaging agents, indicating that 8-GU sensitizes TNF-induced cell death exclusively. Moreover, 8-GU accelerated TNF-driven necroptosis by up-regulating necrosome formation in FADD deficient cancer cells harboring RIPK3. Thus, the present study provides new insights into the molecular mechanism underlying geranylated 7-hydroxy coumarin-mediated control of the RIPK1-dependent early cell death checkpoint and suggests that 8-GU is a potential anti-cancer therapeutic via an alternative apoptosis-independent strategy to overcome TNF resistance.

Insights into cyclooxygenase-2 inhibition by isolated bioactive compounds 3-caffeoyl-4-dihydrocaffeoyl quinic acid and isorhamnetin 3-O-β-D-glucopyranoside from Salicornia herbacea

BACKGROUND

Cyclooxygenase-2 (COX-2) is an important enzyme with numerous biological functions. Overexpression of COX-2 has been associated with various inflammatory-related diseases and therefore, projected as an important pharmacological target.

PURPOSE

We aimed to investigate the inhibitory potential of isolated bioactive compounds, 3-caffeoyl-4-dihydrocaffeoyl quinic acid (CDQ) and isorhamnetin 3-O-β-d-glucopyranoside (IDG), from Salicornia herbacea against COX-2 using both computational and in vitro approaches.

METHODS

Computational analysis, including molecular docking, molecular dynamics (MD) simulations, and post-simulations analysis, were employed to estimate the binding affinity and stability of CDQ and IDG in the catalytic pocket of COX-2 against Celecoxib as positive control. These predictions were further evaluated using in vitro enzyme inhibition as well as gene expression mediation in macrophages cells.

RESULTS

Molecular docking analysis revealed substantial binding energy of CDQ (-6.1 kcal/mol) and IDG (-5.9 kcal/mol) with COX-2, which are lower than Celecoxib (-8.1 kcal/mol). MD simulations (100 ns) and post simulation analysis exhibited the substantial stability and binding affinity of docked CDQ and IDG compounds with COX-2. In vitro assays indicated significant COX-2 inhibition by CDQ (IC₅₀ = 76.91 ± 2.33 μM) and IDG (IC₅₀ = 126.06 ± 9.44 μM). This result supported the inhibitory potential of isolated bioactive compounds against COX-2. Also, a cellular level study revealed a downregulation of COX-2 expression in tumor necrosis factor-alpha stimulated RAW 264.7 macrophages treated with CDQ and IDG.

CONCLUSION

Computational and experimental analysis of CDQ and IDG from S. herbacea established their potential in the inhibition and mediation of COX-2. Hence, CDQ and IDG can be considered for therapeutic development against COX-2 linked disorders, such as inflammation and cancer. Furthermore, CDQ and IDG structures can be served as a lead compound for the development of advanced novel anti-inflammatory drugs.

Molecular design of anticancer drugs from marine fungi derivatives

Heat shock protein 90 (Hsp90) is one of the most potential targets in cancer therapy. We have demonstrated using a combination of molecular docking and fast pulling of ligand (FPL) simulations that marine fungi derivatives can be possible inhibitors, preventing the biological activity of Hsp90. The computational approaches were validated and compared with previous experiments. Based on the benchmark of available inhibitors of Hsp90, the GOLD docking package using the ChemPLP scoring function was found to be superior over both Autodock Vina and Autodock4 in the preliminary estimation of the ligand-binding affinity and binding pose with the Pearson correlation, R = -0.62. Moreover, FPL calculations were also indicated as a suitable approach to refine docking simulations with a correlation coefficient with the experimental data of R = -0.81. Therefore, the binding affinity of marine fungi derivatives to Hsp90 was evaluated. Docking and FPL calculations suggest that five compounds including 23, 40, 46, 48, and 52 are highly potent inhibitors for Hsp90. The obtained results enhance cancer therapy research.

Tulipiferamide A, an Alkamide from Liriodendron tulipifera, Exhibits an Anti-Inflammatory Effect via Targeting IKKβ Phosphorylation

Three new alkamides, tulipiferamides A-C (1-3, respectively), and 30 known compounds (4-33) were obtained from the roots of Liriodendron tulipifera (Magnoliaceae). Dehydrotemisin (4), an elemane sesquiterpene lactone, was isolated for the first time from nature. The structures were deduced by the interpretation of NMR spectroscopic and MS spectral data. The geometries of the double bonds in tulipiferamides A-C (1-3, respectively) were determined on the basis of ¹H-¹H coupling constants and ¹³C chemical shifts. The presence of the alkamide type in this plant is reported for the first time. An analysis of the inflammatory response revealed that seven compounds (1, 4, 7, 9, 14, 23, and 27) suppressed the nitric oxide production induced by LPS in RAW264.7 macrophages. Furthermore, tulipiferamide A (1) inhibits NF-κB activation by selectively targeting IKKβ, an upstream kinase of NF-κB, resulting in the suppression of inflammatory mediators, including iNOS, COX-2, IL-1β, TNFα, and IL-6. Our results provide a rationale for the further development of tulipiferamide A as a selective IKKβ inhibitor to modulate inflammatory diseases.

Paratrimerins J-Y, Dimeric Coumarins Isolated from the Stems of Paramignya trimera

Paratrimerins J-Y (1-13 and 16-18), new dimeric coumarins, were obtained from the EtOH(aq) extract of the stems of Paramignya trimera (Rutaceae) utilizing LC/MS guided isolation. The structures of the dimeric coumarins were elucidated based on 1D/2D NMR spectroscopic and HR-ESIMS data analyses. The absolute configurations of paratrimerins J-Y along with those of two known dimers paratrimerins A (14) and B (15) were established on the basis of the experimental and simulated ECD data. In addition, the absolute configurations of the sugar units of paratrimerins A, B, and J-V (1-15) were confirmed by LC/MS analysis on l-cysteine methyl ester and phenyl isothiocyanate derivatives. The variety of the absolute configurations of the dimeric diastereomers 1-15 highlighted a diversity in stereochemical outcomes following a Diels-Alder biosynthesis in P. trimera. With regard to P. trimera being a recently emerging medicinal resource for liver cancer, the dimers 1-18 were evaluated for cytotoxicity against a wide panel of human cancer cell lines. Paratrimerin W (16) was cytotoxic toward Huh7 hepatocellular carcinoma, HT1080 fibrosarcoma, and HT29 colorectal cancer cells with IC₅₀ values of 14.9, 18.4, and 22.5 μM, respectively.

Extract of Curcuma zedoaria R. prevents atherosclerosis in apolipoprotein E-deficient mice

BACKGROUND/OBJECTIVES

Curcuma zedoaria R. (Zingiberaceae) has been used to treat headache, fever, and hypertension-related symptoms in Asian countries, including Korea, China, and Japan. We investigated whether dietary intake of a C. zedoaria extract (CzE) affected atherosclerosis in vivo.

MATERIALS/METHODS

Apolipoprotein E-deficient (ApoE^−/−) mice (n = 32) were fed a normal diet (ND), a high-cholesterol diet (HCD), an HCD containing CzE (100 mg/kg/day), or an HCD containing simvastatin (10 mg/kg/day) for 12 weeks. The anti-atherosclerotic effects were evaluated by observing changes in fatty streak lesions, immunohistochemical analysis, ex vivo fluorescence imaging, lipid profiles, and western blot analysis.

RESULTS

The CzE-fed group showed a 41.6% reduction of atherosclerosis. Furthermore, CzE significantly reduced the levels of serum triglyceride, high-density lipoprotein, the chemokine (C-X3-C-motif) ligand 1, the adhesion molecules vascular cell adhesion molecule-1, intracellular adhesion molecule-1, and E-selectin; down-regulation of tumor necrosis factor-α, interleukin-6, high mobility group box-1, and cathepsin levels in the aortic sinuses and aortas of ApoE^−/− mice were also observed.

CONCLUSIONS

The results suggest that the inclusion of a water extract of C. zedoaria in a HCD is closely correlated with reducing the risk of vascular inflammatory diseases in an ApoE mouse model.

Discovery and Quantitative Analysis of Nuclear Factor Erythroid 2-Related Factor (Nrf2) Activators in Maca (Lepidium meyenii) Using the Synthetic Macamides

Objectives

Maca (Lepidium meyenii) is a biennial herbaceous plant of family Brassicaceae with various bioactivities such as reproductive health enhancement, antifatigue, antioxidation, neuroprotection, anticancer, hepatoprotection, and immunomodulation. But studies on molecular mechanisms beyond the phenomenal physiology are rare because the putative bioactive chemical constituents, macamides, a series of unique N-benzylamides with long-chain fatty acids are difficult to isolate from the natural maca specimen. In this study, ten macamides were chemically synthesized to investigate biological mechanisms underlying the various bioactivities.

Methods

Macamides were synthesized from benzylamides and commercially available fatty acids adding 1,1'-carbonyl diimidazole. Nrf2 activation of macamides were measured using U2OS cells in CP0. Quantitative analysis of bioactive macamides were performed using LC-MS/MS system and synthesized standard macamides. The difference in composition of macamides among three cultivars, yellow, red and black macas was also examined.

Results

Three of macamides exhibited moderate nuclear factor erythroid 2-related factor 2 (Nrf2) activation was observed from cell-based assay (EC50 7.3–16.5 μM), which might account for some of the known bioactivities of maca. Quantitative analysis of macamide compositions in maca specimen using LC-MS/MS was followed, which revealed the macamides with Nrf2 activation activity consist the majority among macamides contained in maca.

Conclusions

Among the bioactivities that have known as the beneficial effects of maca, bioactivities related to antioxidation might be accounted for the Nrf2 activation of macamides contained in maca.

Funding Sources

This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (2019R1F1A1051041).

Quantitative Analysis of 7 Compounds in Diospyros lotus Leaf Extract and Its Biological Effects on Neuroprotection and Antineuroinflammation

Diospyros lotus L. (Ebenaceae) is a deciduous plant that was traditionally used to treat various diseases such as sedation, constipation, and hypertension. However, its effects on Alzheimer’s diseases (AD) have not been reported. We investigated the potent biological effects of D. lotus on AD and performed quantitative analysis of 7 standard compounds in D. lotus leaves. First, two parts leaf and branch of D. lotus were compared to examine the effects on amyloid-β (Aβ) aggregation and oxidative stress. Ethanol extract of D. lotus leaves (EDLL) had higher activities on the Aβ disaggregation and antioxidation compared with ethanol extract of D. lotus branches (EDLB). Second, we have focused on the biological activities of EDLL for neurocellular analyses. In HT22 neuronal cells, EDLL reversed hydrogen peroxide (H2O2)-damaged cell death. In BV-2 microglia, EDLL suppressed lipopolysaccharide-stimulated productions of nitric oxide (NO) and prostaglandin E2. Third, we performed quantitative analyses of 7 standard compounds in D. lotus using high-performance liquid chromatography. Among 7 compounds, myricitrin (44.189 mg/g) was the most abundant compound in EDLL. Myricetin presented the marked inhibitory effect on Aβ aggregation, indicating its potential as a bioactive compound to control Aβ aggregation. Overall, this study suggests that EDLL may be a promising therapeutic agent for AD via Aβ disaggregation, and inhibition of neuronal cell damage and inflammation.

3-O-acetylrubianol C (3AR-C) induces RIPK1-dependent programmed cell death by selective inhibition of IKKβ

In tumor necrosis factor (TNF) signaling, phosphorylation and activation of receptor interacting protein kinase 1 (RIPK1) by upstream kinases is an essential checkpoint in the suppression of TNF-induced cell death. Thus, discovery of pharmacological agents targeting RIPK1 may provide new strategies for improving the therapeutic efficacy of TNF. In this study, we found that 3-O-acetylrubianol C (3AR-C), an arborinane triterpenoid isolated from Rubia philippinesis, promoted TNF-induced apoptotic and necroptotic cell death. To identify the molecular mechanism, we found that in mouse embryonic fibroblasts, 3AR-C drastically upregulated RIPK1 kinase activity by selectively inhibiting IKKβ. Notably, 3AR-C did not interfere with IKKα or affect the formation of the TNF receptor1 (TNFR1) complex-I. Moreover, in human cancer cells, 3AR-C was only sufficient to sensitize TNF-induced cell death when c-FLIP_L expression was downregulated to facilitate the formation of TNFR1 complex-II and necrosome. Taken together, our study identified a novel arborinane triterpenoid 3AR-C as a potent activator of TNF-induced cell death via inhibition of IKKβ phosphorylation and promotion of the cytotoxic potential of RIPK1, thus providing a rationale for further development of 3AR-C as a selective IKKβ inhibitor to overcome TNF resistance in cancer therpay.

Protective effects of Oxya chinensis sinuosa Mishchenko against ultraviolet B-induced photodamage in hairless mice

Background

Edible insects, including Oxya chinensis sinuosa Mishchenko (Oc), which is consumed as food in Asia, are considered as a human food shortage alternative, and also as a preventive measure against environmental destruction. Ultraviolet B (UVB) irradiation, which causes skin photodamage, is considered as an extrinsic skin aging factor. It reduces skin hydration, and increases wrinkle formation and reactive oxygen species (ROS) and inflammatory cytokine expression. Thus, the objective of this study was to investigate the anti-aging effects of an ethanol extract of Oc (Oc.Ex).

Methods

A UVB-irradiated hairless mouse model was used to examine relevant changes in skin hydration, wrinkle formation, and skin epidermal thickness. Also, antioxidant markers such as superoxide dismutase (SOD) and catalase (CAT) were analyzed, and Oc. Ex skin protective effects against UVB irradiation-induced photoaging were examined by determining the levels of skin hydration factors.

Results

Oc.Ex improved epidermal barrier dysfunctions such as increased transepidermal water loss (TEWL) and capacitance reduction in UVB-irradiated mice. It upregulated skin hydration-related markers, including hyaluronic acid (HA), transforming growth factor (TGF)-β, and pro-collagen, in UVB-irradiated mice, compared with the vehicle control group. It also reduced UVB-induced wrinkle formation, collagen degradation, and epidermal thickness. Additionally, it remarkably suppressed the increased expression of matrix metalloproteinases (MMPs), and restored the activity of SOD and CAT in UVB-irradiated mice, compared with the vehicle control group. Furthermore, Oc. Ex treatment downregulated the production of inflammatory cytokines and phosphorylation of the mitogen-activated protein kinases (MAPKs) signaling pathway activated by UVB irradiation.

Conclusion

This study revealed that Oc. Ex reduced skin thickness and the degradation of collagen fibers by increasing hydration markers and collagen-regulating factors in the skin of UVB-irradiated mice. It also inhibited UVB-induced antioxidant enzyme activity and inflammatory cytokine expression via MAPK signaling downregulation, suggesting that it prevents UVB-induced skin damage and photoaging, and has potential for clinical development in skin disease treatment.

Accelerated degradation of cFLIPL and sensitization of the TRAIL DISC-mediated apoptotic cascade by pinoresinol, a lignan isolated from Rubia philippinensis

Plant-derived lignans have numerous biological effects including anti-tumor and anti-inflammatory activities. Screening of purified constituents of Rubia philippinensis from human glioblastoma cells resistant to TNF-related apoptosis-inducing ligand (TRAIL) has suggested that the lignan pinoresinol was a highly active TRAIL sensitizer. Here we show that treatment with nontoxic doses of pinoresinol in combination with TRAIL induced rapid apoptosis and caspase activation in many types of glioblastoma cells, but not in normal astrocytes. Analyses of apoptotic signaling events revealed that pinoresinol enhanced the formation of TRAIL-mediated death-inducing signaling complex (DISC) and complete processing of procaspase-8 within the DISC in glioblastoma cells, in which caspase-8 was inactivated. Mechanistically, pinoresinol downregulated the expression of cellular FLICE-inhibitory protein (cFLIP_L) and survivin through proteasome-mediated degradation, without affecting death receptors or downstream intracellular apoptosis-related proteins. Furthermore, the sensitization of TRAIL-mediated apoptosis by pinoresinol strictly depended on the expression level of cFLIP_L, which was regulated through de novo protein synthesis, rather than by NF-κB or p53 signaling. Taken together, our results indicate that pinoresinol facilitates DISC-mediated caspase-8 activation by targeting cFLIP_L in an early event in apoptotic signaling, which provides a potential therapeutic module for TRAIL-based chemotherapy.

Oleanane triterpenoids from Rubia philippinensis and their inhibitory effect on 20-HETE synthesis

A new oleanane triterpenoid (2) was isolated from the roots of Rubia philippinensis. The structure of 2 was determined by analysis of HRMS and NMR data and identified as a rubiprasin analogue, 16β-hydroxyrubiprasin B. Four related known compounds were also encountered which include rubiprasin B (1), maslinic acid (3), 4-epi-hederagenin (4) and oleanolic acid (5). The compounds 3-5 displayed moderate inhibitory activity against the synthesis of the eicosanoid 20-HETE.

Hepatoprotective effects of an Acer tegmentosum Maxim extract through antioxidant activity and the regulation of autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Acer tegmentosum Maxim (AT), the East Asian stripe maple, is an herb used to treat liver disease and is approved as a functional food in Korea. AT protects against hepatic disorders, atopic dermatitis, and diabetes mellitus.

AIM OF THE STUDY

We explored the mechanism of the hepatoprotective effects of AT extract in in vitro and in vivo levels.

MATERIALS AND METHODS

AT extract from Acer tegmentosum Maxim was extracted by hot water. Hepatoprotective effects of AT extract were confirmed using carbon tetrachloride (CCl₄)- or alcohol-induced mouse model, and H₂O₂- or alcohol-induced HepG2 (liver hepatocellular carcinoma cell line) cells by measuring GOT, GPT, TG, and MDA levels. Hematoxylin and eosin (H&E) staining was used to observe the pathological analysis. Cytotoxicity or protective effect of AT extract was confirmed using MTT assay in HepG2 cells. Antioxidant effect of AT extract was measured using DPPH or H₂DCFDA assay. Mechanism study of antioxidant and autophagy was carried out using western blotting and immunofluorescence analysis.

RESULTS

AT extract increased the viability of HepG2 cells treated with H₂O₂ and ethanol, and protected the liver against damage induced by CCl₄ and alcohol. The AT extract increased the levels of nuclear respiratory factor 2 (Nrf2) and heme oxygenase-1 (HO-1). The level of microtubule-associated protein light chain 3 (LC3)-Ⅱ, beclin-1, autophagy-related genes (Atg) such as Atg3 and Atg12-5 as markers of autophagy activation was also increased. Moreover, the AT extract increased activation of mitogen-activated protein kinase (MAPK), which regulated autophagy and HO-1.

CONCLUSION

Therefore, these results indicate that the AT extract has a hepatoprotective effect by increasing antioxidant activity and inducing autophagy.

Antithrombotic and Antiplatelet Activities of New Isohopane Triterpene From the Roots of Rubia akane

A new isohopane triterpenoid (1) and two known triterpenoids (2-3) were isolated from the roots of Rubia akane (Rubiaceae). The molecular formula C30H46O4 of 1 was determined by HRESIMS. Detailed NMR spectroscopic data analysis suggested that compound 1 is a new isohopane triterpenoid with a ketone moiety at C-16. Based on the key NOE correlations of H-3/H-5 and H-21/H3-28, compound 1 was determined as 3β-hydroxy-16-oxo-21β-isohop-22(29)-en-24-oic acid. The anticoagulant activities of new isohopane 1 were evaluated by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin (Factor IIa, FIIa) and activated factor X (FXa). The effects of 1 on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor-α activated human umbilical vein endothelial cells. Treatment with 1 (200 μM) resulted in the prolongation of aPTT and PT and the inhibition of relative thrombin (28%) and FXa (29%) activities. In addition, 1 inhibited thrombin-catalyzed fibrin polymerization (18% inhibition at 100 μM) and platelet aggregation (21.8% inhibition at 100 μM). Compound 1 also elicited anticoagulant effects in mice in a dose-dependent manner ranging from 18.8 to 94.0 μg/mouse. In addition, treatment with 1 resulted in significant reduction of the PAI-1 to t-PA ratio (25% decreased). Collectively, the new isohopane triterpenoid 1 possesses antithrombotic activities and offers a basis for the development of a new anticoagulant agent.

The enhancing immune response and anti-inflammatory effects of Anemarrhena asphodeloides extract in RAW 264.7 cells

BACKGROUND

Anemarrhena asphodeloides has been widely used in traditional medicine for thousands of years; it has been reported to improve learning and memory, and to reduce inflammation. However, the role of A. asphodeloides in enhancing the immune response has remained unclear.

PURPOSE

This study aimed to evaluate the effect of A. asphodeloides extract (AA-Ex) on enhancing the immune response in macrophages and to identify the active compounds causing these effects.

STUDY DESIGN/METHODS

To determine the enhancing immune response of AA-Ex and its active compounds, cell proliferation and cell cycle of RAW 264.7 cells were analyzed by MTS assay and flow cytometry. The gene expression of p53, p27, cyclin D2, and cyclin E2 was measured by real-time PCR. To evaluate the anti-inflammatory effects of AA-Ex and its active compounds, the production of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory cytokines was analyzed by Griess reagent, flow cytometry, and real-time PCR. The phosphorylation of p38, c-Jun N-terminal kinase, inhibitory kappa B alpha, and p65 was examined by western blot analysis.

RESULTS

AA-Ex increased cell proliferation by extending the cell cycle S-phase; timosaponin B and timosaponin B-II affected cell proliferation and the cell cycle as active compounds of A. asphodeloides. Next, we determined that A. asphodeloides displayed anti-inflammatory effects, including the inhibition of the production of NO, ROS, and pro-inflammatory cytokines through the suppression of mitogen-activated protein kinase and nuclear factor kappa B phosphorylation downstream of the toll-like receptor 4 signaling pathway. Moreover, we identified that timosaponin B and timosaponin B-II were the active compounds for these effects.

CONCLUSION

Our results suggest that A. asphodeloides promotes the immune response and has anti-inflammatory effects. Moreover, timosaponin B and B-II played important roles as the active compounds of A. asphodeloides in enhancing the immune and anti-inflammatory responses in this model.

Anti-Photoaging Effects of Four Insect Extracts by Downregulating Matrix Metalloproteinase Expression via Mitogen-Activated Protein Kinase-Dependent Signaling

Insects are some of the most diverse organisms on the planet, and have potential value as food or medicine. Here, we investigated the photoprotective properties of insect extracts using hairless mice. The alleviating wrinkle formation effects of insect extracts were evaluated by histological skin analysis to determine epidermal thickness and identify collagen fiber damage. Moreover, we investigated the ability of the insect extracts to alleviate UVB-induced changes to matrix metalloproteinases (MMPs), oxidative damage, the mitogen-activated protein kinases (MAPKs) signaling pathway, and the expression of pro-inflammatory cytokines. Insect extracts reduced UVB-induced skin winkles, epidermal thickening, and collagen breakdown, and alleviated the epidermal barrier dysfunction induced by UVB, including the increased loss of transepidermal water. Moreover, the expression of skin hydration-related markers such as hyaluronic acid, transforming growth factor-beta (TGF-β), and procollagen was upregulated in the group treated with insect extracts compared to the vehicle-treated group after ultraviolet B (UVB) exposure. UVB irradiation also upregulated the expression of MMPs, the phosphorylation of MAPKs, and pro-inflammatory cytokines, which were all attenuated by the oral administration of insect extracts. These results indicate the photoaging protection effect of insect extracts and the underlying mechanism, demonstrating the potential for clinical development.

Anthraquinone-type inhibitor of α-glucosidase enhances glucose uptake by activating an insulin-like signaling pathway in C2C12 myotubes

This study assesses the ability of anthraquinone derivative, 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (MTAQ) to decrease postprandial hyperglycemia or enhance glucose uptake and to elucidate the underlying molecular mechanism. We investigated α-glucosidase inhibition, glucose uptake, and translocation of glucose transporter 4 (GLUT4) in C2C12 myotubes. The data indicate that MTAQ strongly inhibited α-glucosidase activity in a concentration-dependent manner, with an IC₅₀ value of 6.49 ± 1.31 μM, and functioned as a reversible competitive inhibitor, with a dissociation constant of 41.88 μM. Moreover, MTAQ significantly augmented basal and insulin-stimulated glucose uptake as well as translocation of GLUT4 to the plasma membrane. It also stimulated the phosphorylation of insulin receptor β isoform, insulin receptor substrate-1,3-phosphoinositide-dependent protein kinase 1, and protein kinase B (AKT). A pretreatment with an AKT inhibitor, LY294002, attenuated the ability of MTAQ to activate an insulin-like signaling pathway and to enhance basal and insulin-stimulated glucose uptake and stimulate GLUT4 translocation to the plasma membrane. These findings reveal the fact that MTAQ may have potential for the development of new antidiabetic drugs to manage blood glucose levels.

Protopine isolated from Nandina domestica induces apoptosis and autophagy in colon cancer cells by stabilizing p53

The tumor suppressor p53 plays essential roles in cellular protection mechanisms against a variety of stress stimuli and its activation induces apoptosis or autophagy in certain cancer cells. Here, we identified protopine, an isoquinoline alkaloid isolated from Nandina domestica, as an activator of the p53 pathway from cell-based natural compound screening based on p53-responsive transcription. Protopine increased the p53-mediated transcriptional activity and promoted p53 phosphorylation at the Ser15 residue, resulting in stabilization of p53 protein. Moreover, protopine up-regulated the expression of p21^WAF1/CIP1 and BAX, downstream genes of p53, and inhibited the proliferation of HCT116 colon cancer cells. Apoptosis was elicited by protopine as indicated by caspase-3/7 activation, poly ADP ribose polymerase cleavage, and increased population of Annexin V-FITC-positive cells. Furthermore, protopine induced the formation of microtubule-associated protein 1 light chain 3 (LC3) puncta and LC3-II turnover, typical biochemical markers of autophagy, in HCT116 cells. Our findings suggest that protopine exerts its antiproliferative activity by stimulating the p53 pathway and may have potential as a chemopreventive agent for human colon cancer.

HPLC-MS/MS analysis of ilimaquinone and its application in a pharmacokinetic study in rats

Ilimaquinone, a metabolite isolated from the marine sponge Hippiospongia metachromia, has antimicrobial, cytotoxic, anti-HIV, anti-inflammatory, and anti-cancer activities. A new quantitative analytical method for determination of ilimaquinone in rat plasma using HPLC-MS/MS was developed and validated. Ascorbic acid was added to ensure the stability of ilimaquinone in plasma. After protein precipitation using acetonitrile plus diclofenac as an internal standard, the analytes were chromatographed on a biphenyl column with a mobile phase of methanol and water (8:2, v/v, including 0.1% formic acid). This method was successfully applied in a pharmacokinetic study of ilimaquinone after oral administration in rats.

NMR-Based Investigation of Hydrogen Bonding in a Dihydroanthracen-1(4 H)one from Rubia philippinensis and Its Soluble Epoxide Hydrolase Inhibitory Potential

Hydrogen bonding is a vital feature of a large ensemble of chemical structures. Soluble epoxide hydrolase (sEH) has been targeted for development of the treatment for inflammation-associated diseases. Compounds 1 and 2 were purified from Rubia philippinensis, and their structures were established via physical data analysis. Compound 1 possesses intramolecular hydrogen bonding, sufficiently robust to transfer heteronuclear magnetization via a nonbonded interaction. The bonding strength was assessed using the ¹H NMR chemical shift temperature coefficients (-1.8 ppb/K), and the heteronuclear coupling constants were measured. The stereochemical details were investigated using interproton distance analysis and ECD. Purified compounds displayed moderate sEH-inhibitory activity.

C-27-carboxylated oleanane triterpenoids up-regulate TRAIL DISC assembly via p38 MAPK and CHOP-mediated DR5 expression in human glioblastoma cells

Despite recent tremendous progress, targeting of TNF-related apoptosis-inducing ligand (TRAIL) as a cancer therapy has limited success in many clinical trials, in part due to inactivation of death inducing signaling complex (DISC)-mediated caspase-8 signaling cascade in highly malignant tumors such as glioblastoma. In this study, screening of constituents derived from Astilbe rivularis for TRAIL-sensitizing activity identified C-27-carboxylated oleanolic acid derivatives (C27OAs) including 3β-hydroxyolean-12-en-27-oic acid (C27OA-1), 3β,6β,7α-trihydroxyolean-12-en-27-oic acid (C27OA-2), and 3β-trans-p-coumaroyloxy-olean-12-en-27-oic acid (C27OA-3) as novel TRAIL sensitizers. Interestingly, these C27OAs did not affect apoptotic cell death induced by either ligation of other death receptor (DR) types, such as TNF and Fas or DNA damaging agents, which suggests that C27OAs effectively and selectively sensitize TRAIL-mediated caspase-8 activation. Mechanistically, C27OAs upregulate the expression of cell surface DR5 and DISC formation without affecting downstream intracellular apoptosis-related proteins. The upregulation of DR5 expression by C27OAs strictly depends on transactivation of C/EBP homology protein, which is regulated through the p38 MAPK pathway, rather than p53 and intracellular reactive oxygen species status. Taken together, our results identify the novel C27OAs as TRAIL sensitizers targeting the upstream DISC assembly of DR5, and provide a rationale for further development of C27OAs for facilitating TRAIL-based chemotherapy in glioblastoma patients.

Antioxidant and antimicrobial efficacy of a biflavonoid, amentoflavone from Nandina domestica in vitro and in minced chicken meat and apple juice food models

A biflavonoid, amentoflavone isolated from Nandina domestica and characterized by NMR spectral-data analyses was assessed for its antioxidant, and antibacterial potential in vitro and in food-model systems. Amentoflavone exhibited potent antioxidant ability (19.21-75.52%) on scavenging DPPH, ABTS, superoxide, and hydroxyl radicals. Fluorescent images confirmed bacterial membrane depolarization of both the tested pathogens Staphylococcus aureus and Escherichia coli, with a significant reduction in cell viabilities at their respective MIC of 62.5 and 125 µg/mL. Increasing rates of membrane permeability observed in 260 nm-absorbing material, potassium ion, extracellular ATP, and relative electrical conductivity assays confirmed antibacterial mechanistic role of amentoflavone as also evidenced by microscopic studies of SEM and TEM. There was a marked inhibitory effect of amentoflavone with a significant reduction in cell counts of S. aureus and E. coli in minced chicken and apple juice at 4 °C, thus suggesting its nutritional enhancing efficacy as a natural antioxidant and antimicrobial agent.

Cytotoxic properties of the anthraquinone derivatives isolated from the roots of Rubia philippinensis

Background

Cancer is one of the most frequently occurring diseases and is the second leading cause of death worldwide. In this study, anthraquinone derivatives (Compounds 1–5) were evaluated for their anti-cancer potential against various skin and breast cancer cell lines to assess whether these anthraquinone derivatives may serve as a lead for the augmentation of anti-cancer drug.

Methods

Anthraquinone derivatives, 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6′-O-acetyl)-α-rhamnosyl(1 → 2)-β-glucoside (Comp 1), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (Comp 2), and alizarin (Comp 3) were isolated from the dichloromethane fraction of the roots of Rubia philippinensis., whereas ethyl acetate fraction yielded xanthopurpurin (Comp 4) and lucidin-ω-methyl ether (Comp 5). Structures of all the isolated compounds were determined by spectral data analysis. All isolated compounds (Comp 1–5) were assessed for cytotoxicity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against four different cancer cell lines, i.e. human melanoma (SK-MEL-5), murine melanoma (B16F10), and human breast adenocarcinoma (MCF7 and MDA-MB-231).

Results

Significant activity of the compounds 4 and 5 was observed against the breast cancer cell line MDA-MB-231 with IC₅₀ values of 14.65 ± 1.45 and 13.03 ± 0.33 μM, respectively. Encouragingly, IC₅₀ values of 67.89 ± 1.02 and 79.01 ± 0.03 μM against normal kidney epithelial cells (MDCK) were also obtained for compounds 4 and 5, respectively, which indicated very low toxicity and favorable selectivity indices for compounds 4 and 5 in the range of 1.85 to 3.95 and 2.11 to 6.06 against skin cancer cell lines (SK-MEL-5, and B16F10), and breast cancer cell lines (MCF7 and MDA-MB-231), respectively.

Conclusion

Our results suggested that the compounds 4 (xanthopurpurin) and 5 (lucidin-ω-methyl ether) showed high selective toxicity towards breast cancer cells at lower concentrations without showing toxicity towards normal cells, thus could be of potential as new lead molecules in cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2253-2) contains supplementary material, which is available to authorized users.

Attenuation of inflammatory responses by (+)-syringaresinol via MAP-Kinase-mediated suppression of NF-κB signaling in vitro and in vivo

We examined the anti-inflammatory effects of (+)-syringaresinol (SGRS), a lignan isolated from Rubia philippinensis, in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells using enzyme-based immuno assay, Western blotting, and RT-PCR analyses. Additionally, in vivo effects of SGRS in the acute inflammatory state were examined by using the carrageenan-induced hind paw edema assay in experimental mice. As a result, treatment with SGRS (25, 50, and 100 μM) inhibited protein expression of lipopolysaccharide-stimulated inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor kappa B (NF-κB) as well as production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and interleukin-6 (IL-6) induced by LPS. Moreover, SGRS also reduced LPS-induced mRNA expression levels of iNOS and COX-2, including NO, PGE2, TNF-α, IL-1β, and IL-6 cytokines in a dose-dependent fashion. Furthermore, carrageenan-induced paw edema assay validated the in vivo anti-edema effect of SGRS. Interestingly, SGRS (30 mg/kg) suppressed carrageenan-induced elevation of iNOS, COX-2, TNF-α, IL-1β, and IL-6 mRNA levels as well as COX-2 and NF-κB protein levels, suggesting SGRS may possess anti-inflammatory activities.

Rubiarbonone C inhibits platelet-derived growth factor-induced proliferation and migration of vascular smooth muscle cells through the focal adhesion kinase, MAPK and STAT3 Tyr705 signalling pathways

BACKGROUND AND PURPOSE

The proliferation and migration of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor (PDGF) are important steps in cardiovascular diseases, including neointimal lesion formation, myocardial infarction and atherosclerosis. Here, we evaluated the rubiarbonone C-mediated signalling pathways that regulate PDGF-induced VSMC proliferation and migration.

EXPERIMENTAL APPROACH

Cell proliferation and migration were measured in cells treated with rubiarbonone C followed by PDGF BB using the MTT assay, [³ H]-thymidine incorporation, flow cytometry and wound-healing migration assay, MMP gelatin zymography, a fluorescence assay for F-actin. Western blotting of molecules including MAPK, focal adhesion kinase (FAK) and STAT3 and an immunofluorescence assay using anti-PCNA and -STAT3 antibodies were performed to evaluate rubiarbonone C signalling pathway(s). The medial thickness of the carotid artery was evaluated using a mouse carotid ligation model.

KEY RESULTS

Rubiarbonone C inhibited PDGF-induced VSMC proliferation and migration and diminished the ligation-induced increase in medial thickness of the carotid artery. In PDGF-stimulated VSMCs rubiarbonone C decreased the following: (i) levels of cyclin-dependent kinases, cyclins, PCNA and hyperphosphorylated retinoblastoma protein; (ii) levels and activity of MMP2 and MMP9; (iii) activation of MAPK; (iv) F-actin reorganization, by reducing FAK activation; (v) activation of STAT3.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that rubiarbonone C inhibits the proliferation and migration of VSMCs by inhibiting the FAK, MAPK and STAT3 signalling pathways. Therefore, rubiarbonone C could be a good candidate for the treatment of cardiovascular disease.

Ghost probiotics with a combined regimen: a novel therapeutic approach against the Zika virus, an emerging world threat

The Zika virus (ZIKV) used to be an obscure flavivirus closely related to dengue virus (DENV). Transmission of this epidemic pathogen occurs mainly via mosquitoes, but it is also capable of placental and sexual transmission. Although the characteristics of these viruses are well defined, infections are unpredictable in terms of disease severity, unusual clinical manifestations, unexpected methods of transmission, long-term persistence, and the development of new strains. Recently, ZIKV has gained huge medical attention following the large-scale epidemics around the world, and reported cases of congenital abnormalities associated with Zika virus infections which have created a public health emergency of international concern. Despite continuous research on ZIKV, no specific treatment or vaccine has been developed, excepting a preventive strategy for congenital ZIKV infection. Probiotics, known as GRAS, are bacteria that confer various health beneficial effects, and have been shown to be effective at curing a number of viral diseases by modulating the immune system. Furthermore, probiotic preparations consisting of dead cells and cellular metabolites, so-called "Ghost probiotics", can also act as biological response modifiers. Here, we review available information on the epidemiology, transmission, and clinical features of ZIKV, and on treatment and prevention strategies. In addition, we emphasize the use of probiotics and plant-based natural remedies and describe their action mechanisms, and the green technologies for microbial conversion, which could contribute to the development of novel therapies that may reduce the pathogenicity of ZIKV. Accordingly, we draw attention to new findings, unanswered questions, unresolved issues, and controversies regarding ZIKV.

Novel direct factor Xa inhibitory compounds from Tenebrio molitor with anti-platelet aggregation activity

Tenebrio molitor is an edible insect that has antimicrobial, anticancer, and antihypertensive effects. The aim of this study was to identify the unreported bioactive compounds from T. molitor larvae with inhibitory activities against factor Xa (FXa) and platelet aggregation. Isolated compounds were evaluated for their anti-FXa and anti-platelet aggregation properties by monitoring clotting time, platelet aggregation, FXa activity, and thrombus formation. A diketopiperazine (1, cyclo(_L-Pro-_L-Tyr)) and a phenylethanoid (2, N-acetyltyramine) were isolated and inhibited the catalytic activity of FXa in a mixed inhibition model and inhibited platelet aggregation induced by adenosine diphosphate (ADP) and U46619. They inhibited ADP- and U46619-induced phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS) and the expression of P-selectin and PAC-1 in platelets. They also improved the production of nitric oxide and inhibited the oversecretion of endothelin-1 compared to that of the ADP- or U46619-treated group. In an animal model of arterial and pulmonary thrombosis, the isolated compounds showed enhanced antithrombotic effects. They also elicited anticoagulant effects in mice. Compounds 1-2 inhibited ADP-, collagen-, or U46619-induced platelet aggregation and showed similar anti-thrombotic efficacy to rivaroxaban, a positive control. Therefore, 1-2 could serve as candidates and provide scaffolds for the development of new anti-FXa and anti-platelet drugs.

Evaluation of novel factor Xa inhibitors from Oxya chinensis sinuosa with anti-platelet aggregation activity

The edible grasshopper Oxya chinensis sinuosa is consumed worldwide for its various medicinal effects. The purpose of this study was to investigate potential bioactive antithrombotic and antiplatelet compounds from O. chinensis sinuosa. Five N-acetyldopamine dimers (1–5) were isolated from O. chinensis sinuosa and compounds 1 and 2 were identified as new chemicals with chiral centers at H-2 and H-3 of the benzo-1,4-dioxane structure. Compounds 1–4 were found to have both FXa and platelet aggregation inhibitory activities. These compounds inhibited the catalytic activity of FXa toward its synthetic substrate, S-2222, by noncompetitive inhibition, and inhibited platelet aggregation induced by ADP and U46619. Furthermore, compounds 1–4 showed enhanced antithrombotic effects, which were assessed using in vivo models of pulmonary embolism and arterial thrombosis. The isolated compounds also showed anticoagulant effects in mice. However, compounds 1–4 did not prolong bleeding time in mice, as shown by tail clipping. N-Acetyldopamine dimers, including two new stereoisomers 1 and 2, are novel antithrombotic compounds showing both FXa inhibition and antiplatelet aggregation activity with a low bleeding risk. Collectively, these results suggest that compounds 1–4 could serve as candidates and provide scaffolds for development of new antithrombotic drugs.

Quinoxaline-, dopamine-, and amino acid-derived metabolites from the edible insect Protaetia brevitarsis seulensis

Edible insects have been reported to produce metabolites showing various pharmacological activities, recently emerging as rich sources of health functional food. In particular, the larvae of Protaetia brevitarsis seulensis (Kolbe) have been used as traditional Korean medicines for treating diverse diseases, such as breast cancer, inflammatory disease, hepatic cancer, liver cirrhosis, and hepatitis. However, only few chemical investigations were reported on the insect larvae. Therefore, the aim of this study was to discover and identify biologically active chemical components of the larvae of P. brevitarsis seulensis. As a result, a quinoxaline-derived alkaloid (1) was isolated, which was not reported previously from natural sources. In addition, other related compounds (2, 4-10, 15, 16) were also encountered for the first time from the larvae. The structures of all the isolated compounds were established mainly by analysis of HRESIMS, NMR, and electronic circular dichroism data. Compound 5 exhibited inhibition of tyrosinase with IC₅₀ value of 44.8 µM.

Efficacy of (+)-Lariciresinol to Control Bacterial Growth of Staphylococcus aureus and Escherichia coli O157:H7

This study was undertaken to assess the antibacterial potential of a polyphenolic compound (+)-lariciresinol isolated from Rubia philippinensis against selected foodborne pathogens Staphylococcus aureus KCTC1621 and Escherichia coli O157:H7. (+)-Lariciresinol at the tested concentrations (250 μg/disk) evoked a significant antibacterial effect as a diameter of inhibition zones (12.1-14.9 mm) with minimum inhibitory concentration (MIC), and minimum bactericidal concentration values of 125-250 and 125-250 μg/mL, respectively. Furthermore, (+)-lariciresinol at MIC showed reduction in bacterial cell viabilities, efflux of potassium (K⁺) ions and release of 260 nm materials against E. coli O157:H7 and S. aureus KCTC1621. Moreover, deteriorated cell wall morphology of E. coli O157:H7 and S. aureus KCTC1621 cells treated with (+)-lariciresinol at MIC further confirmed its inhibitory effect against the tested pathogens, suggesting it to be an alternative means of antimicrobials.

Inhibition of melanogenesis by jineol from Scolopendra subspinipes mutilans via MAP-Kinase mediated MITF downregulation and the proteasomal degradation of tyrosinase

In this study, the authors investigated the anti-melanogenic effects of 3,8-dihydroxyquinoline (jineol) isolated from Scolopendra subspinipes mutilans, the mechanisms responsible for its inhibition of melanogenesis in melan-a cells, and its antioxidant efficacy. Mushroom tyrosinase activities and melanin contents were determined in melan-a cells, and the protein and mRNA levels of MITF, tyrosinase, TYRP-1, and TYRP-2 were assessed. Jineol exhibited significant, concentration-dependent antioxidant effects as determined by DPPH, ABTS, CUPRAC, and FRAP assays. Jineol significantly inhibited mushroom tyrosinase activity by functioning as an uncompetitive inhibitor, and markedly inhibited melanin production and intracellular tyrosinase activity in melan-a cells. In addition, jineol abolished the expressions of tyrosinase, TYRP-1, TYRP-2, and MITF, thereby blocking melanin production and interfering with the phosphorylations of ERK1/2 and p38. Furthermore, specific inhibitors of ERK1/2 and p38 prevented melanogenesis inhibition by jineol, and the proteasome inhibitor (MG-132) prevented jineol-induced reductions in cellular tyrosinase levels. Taken together, jineol was found to stimulate MAP-kinase (ERK1/2 and p38) phosphorylation and the proteolytic degradation pathway, which led to the degradations of MITF and tyrosinase, and to suppress the productions of melanin.