Correction: Nukulkit et al. Eight Indole Alkaloids from the Roots of Maerua siamensis and Their Nitric Oxide Inhibitory Effects. Molecules 2022, 27, 7558

After a proofreading check, some experimental data were inconsistent with the supplementary information in the original publication [...].

Cardenolide glycosides sensitize gefitinib-induced apoptosis in non-small cell lung cancer: inhibition of Na+/K+-ATPase serving as a switch-on mechanism

The treatment of non-small cell lung cancer (NSCLC) is known as a significant level of unmet medical need in spite of the progress in targeted therapy and personalized therapy. Overexpression of the Na+/K+-ATPase contributes to NSCLC progression, suggesting its potentiality in antineoplastic approaches. Epi-reevesioside F, purified from Reevesia formosana, showed potent anti-NSCLC activity through inhibiting the Na+/K+-ATPase, leading to internalization of α1- and α3-subunits in Na+/K+-ATPase and suppression of Akt-independent mTOR-p70S6K-4EBP1 axis. Epi-reevesioside F caused a synergistic amplification of apoptosis induced by gefitinib but not cisplatin, docetaxel, etoposide, paclitaxel, or vinorelbine in both NCI-H460 and A549 cells. The synergism was validated by enhanced activation of the caspase cascade. Bax cleavage, tBid formation, and downregulation of Bcl-xL and Bcl-2 contributed to the synergistic apoptosis induced by the combination treatment of epi-reevesioside F and gefitinib. The increase of membrane DR4 and DR5 levels, intracellular Ca2+ concentrations, and active m-calpain expression were responsible for the caspase-8 activation and Bax cleavage. The increased α-tubulin acetylation and activation of MAPK (i.e., p38 MAPK, Erk, and JNK) depending on cell types contributed to the synergistic mechanism under combination treatment. These signaling pathways that converged on profound c-Myc downregulation led to synergistic apoptosis in NSCLC. In conclusion, the data suggest that epi-reevesioside F inhibits the Na+/K+-ATPase and displays potent anti-NSCLC activity. Epi-reevesioside F sensitizes gefitinib-induced apoptosis through multiple pathways that converge on c-Myc downregulation. The data support the inhibition of Na+/K+-ATPase as a switch-on mechanism to sensitize gefitinib-induced anti-NSCLC activity.

Indigofera suffruticosa aerial parts extract induce G2/M arrest and ATR/CHK1 pathway in Jurkat cells

BACKGROUND

Indigofera suffruticosa Mill. is used as a folk medicine for treating patients with leukemia, however very little is known regarding the molecular mechanism of its anti-leukemic activity and the chemical profile of the active extract. The present study aimed to reveal the molecular effect of I. suffruticosa aerial parts extract (ISAE) on leukemia cells and its chemical constituents.

METHODS

Cytotoxicity of ISAE were determined by resazurin viability assay, multitox - Glo multiplex cytotoxicity assay, and Annexin V staining assay. Cell cycle profiles were revealed by propidium iodide staining assay. The effects of ISAE on G2/M arrest signaling and DNA damage were evaluated by Western blot assay and phospho-H2A.X staining assay. The chemical profile of ISAE were determined by tandem mass spectroscopy and molecular networking approach.

RESULTS

We showed that the acute lymphoblastic leukemia cell line Jurkat cell was more responsive to ISAE treatment than other leukemia cell lines. In contrast, ISAE did not induce cytotoxic effects in normal fibroblast cells. Cell cycle analysis revealed that ISAE triggered G2/M arrest in Jurkat cells in dose- and time-dependent manners. Elevation of annexin V-stained cells and caspase 3/7 activity suggested ISAE-induced apoptosis. Furthermore, ISAE alone could increase the phosphorylation of CDK1 at Y15 and activate the ATR/CHK1/Wee1/CDC25C signaling pathway. However, the addition of caffeine, a widely used ATR inhibitor to ISAE, reduced the phosphorylation of ATR, CHK1, and CDK1, as well as G2/M arrest in Jurkat cells. Moreover, increased phospho-H2A.X stained cells indicated the involvement of DNA damage in the anti-leukemic effect of ISAE. Finally, qualitative analysis using UPLC-tandem mass spectroscopy and molecular networking revealed that tryptanthrin was the most abundant organoheterocyclic metabolite in ISAE. At equivalent concentrations to ISAE, tryptanthrin induced G2/M arrest of Jurkat cells, which can be prevented by caffeine.

CONCLUSIONS

ISAE causes G2/M arrest via activating ATR/CHK1/CDK1 pathway and tryptanthrin is one of the active components of ISAE. Our findings provide subtle support to the traditional use of I. suffruitcosa in leukemia management in folk medicine.

Transient plasticity response is regulated by histone deacetylase inhibitor in oxygen-glucose deprivation condition

BACKGROUND

The pathological form of synaptic plasticity, ischemic long-term potentiation (iLTP), induced by oxygen and glucose deprivation (OGD), is implicated in the acute phase of stroke with the potentiation of N-methyl-D-aspartate receptor (NMDAR). While there has been widespread attention on the excitatory system, a recent study reported that γ-aminobutyric acid (GABA)ergic system is also involved in iLTP. Valproic acid (VPA), a histone deacetylase inhibitor, protects against ischemic damage. However, whether VPA regulates early phase plasticity in ischemic stroke remains unknown. The present study aims to investigate the potential role and mechanism of VPA in ischemic stroke.

METHODS

A brief exposure of OGD on the hippocampal slices and the induction of photothrombotic ischemia (PTI) were used as ex vivo and in vivo models of ischemic stroke, respectively.

RESULTS

Using extracellular recordings, iLTP was induced in the hippocampal Schaffer collateral pathway following OGD exposure. VPA treatment abolished hippocampal iLTP via GABAA receptor enhancement and extracellular signal-regulated kinase (ERK) phosphorylation. Administration of VPA reduced brain infarct volume and motor dysfunction in mice with PTI. Moreover, VPA protected against ischemic injury by upregulating the GABAergic system and ERK phosphorylation, as well as by reducing of matrix metalloproteinase in a PTI-induced ischemic stroke model.

CONCLUSIONS

Together, this study revealed the protection of VPA in ex vivo OGD-induced pathological form of neuroplasticity and in vivo PTI-induced brain damage and motor dysfunction through rescuing GABAergic deficiency and the pathological hallmarks of ischemia.

Chemical Constituents with Anti-Lipid Droplet Accumulation and Anti-Inflammatory Activity from Elaeagnus glabra

Non-alcoholic fatty liver disease (NAFLD) is a type of steatosis caused by excess lipids accumulating in the liver. The prevalence of NAFLD has increased annually due to modern lifestyles and a lack of adequate medical treatment. Thus, we were motivated to investigate the bioactive components of Formosan plants that could attenuate lipid droplet (LD) accumulation. In a series of screenings of 3000 methanolic extracts from the Formosan plant extract bank for anti-LD accumulation activity, the methanolic extract of aerial parts of Elaeagnus glabra Thunb. showed excellent anti-LD accumulation activity. E. glabra is an evergreen shrub on which only a few phytochemical and biological studies have been conducted. Here, one new flavonoid (1), two new triterpenoids (2 and 3), and 35 known compounds (4-38) were isolated from the ethyl acetate layer of aerial parts of E. glabra via a bioassay-guided fractionation process. Their structures were characterized by 1D and 2D NMR, UV, IR, and MS data. Among the isolated compounds, methyl pheophorbide a (37) efficiently reduced the normalized LD content to 0.3% with a concentration of 20 μM in AML12 cell lines without significant cytotoxic effects. 3-O-(E)-Caffeoyloleanolic acid (13) and methyl pheophorbide a (37) showed inhibitory effects on superoxide anion generation or elastase release in fMLP/CB-treated human neutrophils (IC50 < 3.0 μM); they displayed effects similar to those of the positive control, namely, LY294002. These findings indicate that E. glabra can be used for developing a new botanical drug for managing LD accumulation and against inflammation-related diseases.

An efficient cellular image-based platform for high-content screening of neuroprotective agents against chemotherapy-induced neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect, with no approved therapy for prevention or treatment. Here, we aimed to establish a high-content image platform based on the neurite outgrowth of dorsal root ganglia (DRG)-derived neuron cells for the discovery of neuroprotective agents against paclitaxel-induced CIPN. ND7/23 cells, an immortalized hybrid DRG cell line, were maturely differentiated by induction with nerve growth factor and upregulation of intracellular cAMP levels. High-content image analyses of the neurofilament-stained neurite network showed that paclitaxel disrupted the neurite outgrowth of well-differentiated ND7/23 DRG neuron cells, recapitulating characteristic effects of paclitaxel on primary cultured DRG neurons. This process coincided with the upregulated activity of store-operated Ca²⁺ entry, similar to those found in rodent models of paclitaxel-induced CIPN. The previously identified neuroprotective agents, minoxidil and 8-Br-cyclic adenosine monophosphate ribose (8-Br-cADPR), attenuated the reduction in total neurite outgrowth in paclitaxel-damaged ND7/23 cells. Additionally, the total neurite outgrowth of well-differentiated ND7/23 cells was concentration-dependently reduced by the neurotoxic chemotherapeutic agents, oxaliplatin and bortezomib, but not the less neurotoxic 5-fluorouracil. We demonstrated that high-content analyses of neurite morphology in well-differentiated DRG neuron-derived cells provide an effective, reproducible, and high-throughput strategy for developing therapeutics against CIPN.

Different synaptic mechanisms of intermittent and continuous theta-burst stimulations in a severe foot-shock induced and treatment-resistant depression in a rat model

Treatment-resistant depression (TRD) is a condition wherein patients with depression fail to respond to antidepressant trials. A new form of repetitive transcranial magnetic stimulation (rTMS), called theta-burst stimulation (TBS), which includes intermittent theta-burst stimulation (iTBS) and continuous theta-burst stimulation (cTBS), is non-inferior to rTMS in TRD treatment. However, the mechanism of iTBS and cTBS underlying the treatment of TRD in the prefrontal cortex (PFC) remains unclear. Hence, we applied foot-shock stress as a traumatic event to develop a TRD rat model and investigated the different mechanisms of iTBS and cTBS. The iTBS and cTBS treatment were effective in depressive-like behavior and active coping behavior. The iTBS treatments improved impaired long-term potentiation and long-term depression (LTD), whereas the cTBS treatment only improved aberrant LTD. Moreover, the decrease in mature brain-derived neurotrophic factor (BDNF)-related protein levels were reversed by iTBS treatment. The decrease in proBDNF-related protein expression was improved by iTBS and cTBS treatment. Both iTBS and cTBS improved the decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and downregulation of mammalian target of the rapamycin (mTOR) signaling pathway. The iTBS produces both excitatory and inhibitory synaptic effects, and the cTBS only produces inhibitory synaptic effects in the PFC.

In vitro and in silico studies of 7'',8''-buddlenol D anti-inflammatory lignans from Carallia brachiata as p38 MAP kinase inhibitors

Excessive macrophage activation induces the release of high levels of inflammatory mediators which not only amplify chronic inflammation and degenerative diseases but also exacerbate fever and retard wound healing. To identify anti-inflammatory molecules, we examined Carallia brachiata-a medicinal terrestrial plant from Rhizophoraceae. Furofuran lignans [(-)-(7''R,8''S)-buddlenol D (1) and (-)-(7''S,8''S)-buddlenol D (2)] isolated from the stem and bark inhibited nitric oxide (half maximal inhibitory concentration (IC₅₀): 9.25 ± 2.69 and 8.43 ± 1.20 micromolar for 1 and 2, respectively) and prostaglandin E₂ (IC₅₀: 6.15 ± 0.39 and 5.70 ± 0.97 micromolar for 1 and 2, respectively) productions in lipopolysaccharide-induced RAW264.7 cells. From western blotting, 1 and 2 suppressed LPS-induced inducible nitric oxide synthase and cyclooxygenase-2 expression in a dose-dependent manner (0.3-30 micromolar). Moreover, analysis of the mitogen-activated protein kinase (MAPK) signaling pathway showed decreased p38 phosphorylation levels in 1- and 2-treated cells, while phosphorylated ERK1/2 and JNK levels were unaffected. This discovery agreed with in silico studies which suggested 1 and 2 bound to the ATP-binding site in p38-alpha MAPK based on predicted binding affinity and intermolecular interaction docking. In summary, 7'',8''-buddlenol D epimers demonstrated anti-inflammatory activities via p38 MAPK inhibition and may be used as viable anti-inflammatory therapies.

Chemical investigations and cytotoxic effects of metabolites from Antrodia camphorata against human hepatocellular carcinoma cells

Antrodia camphorata is used as a medicinal fungus in Taiwan to treat fatigue, food intoxication, and enhance liver function. Here we identified fermented metabolic components from the mycelium of A. camphorata KH37 and explored their anti-hepatoma potentials with study models of human hepatoblastoma cell lines. Bioassay-guided fractionation of the solid fermentation powder of A. camphorata KH37 led to the isolation of one new quinonol, antroquinonol Z (1), and nine known compounds (2-10). Treatment with 10 μM antrocamols LT1 (2) or LT3 (3) reduced cell viability of HepG2 and Huh-7 cells to about 60% in 48 hours. Antroquinonol Z (1) exhibited mild cytotoxicity against Huh-7 cells in 48 and 72 hours. Interestingly, two fractions showed cytotoxicity in HepG2 and Huh-7 cells, even better than compounds isolated from these fractions. The significant cytotoxicity of partially purified samples from A. camphorata KH37 exhibited a potential for developing alternative or complementary therapeutics against hepatoma.

Eight Indole Alkaloids from the Roots of Maerua siamensis and Their Nitric Oxide Inhibitory Effects

Maerua siamensis (Capparaceae) roots are used for treating pain and inflammation in traditional Thai medicine. Eight new indole alkaloids, named maeruanitriles A and B, maeroximes A-C, and maeruabisindoles A-C, were isolated from them. Spectroscopic methods and computational analysis were applied to determine the structure of the isolated compounds. Maeroximes A-C possesses an unusual O-methyloxime moiety. The bisindole alkaloid maeruabisindoles A and B possess a rare azete ring, whereas maeruabisindole C is the first indolo[3,2-b]carbazole derivative found in this plant family. Five compounds [maeruanitriles A and B, maeroxime C, maeruabisindoles B, and C] displayed anti-inflammatory activity by inhibiting nitric oxide (NO) production in the lipopolysaccharide-induced RAW 264.7 cells. Maeruabisindole B was the most active inhibitor of NO production, with an IC50 of 31.1 ± 1.8 μM compared to indomethacin (IC50 = 150.0 ± 16.0 μM) as the positive control.

Undescribed alkyne-geranylcyclohexenetriols from the endophyte Diaporthe caulivora 09F0132 and their anti-melanogenic activity

To explore valuable endophytic fungus from Formosan Lauraceous plants as natural medicinal products, the fungus, Diaporthe caulivora isolated from leaves of Neolitsea daibuensis, was investigated. Through a thorough investigation of the ethanolic extract of the solid fermentation of D. caulivora 09F0132, six undescribed alkyne-geranylcyclohexenetriols, caulivotrioloxins A-F, one undescribed trichopyrone, diapopyrone, two undescribed sesquiterpenes, caulibysins A-B, one compound firstly isolated from the natural source, 3-O-desmethyl phomentrioloxin, and eight known compounds have been successfully identified. The absolute configuration of caulibysin A was confirmed by single-crystal X-ray diffraction, and those of (3R,8S)-5,7-dihydroxy-3-(1-hydroxyethyl)phthalide and (3S,8S)-5,7-dihydroxy-3-(1-hydroxyethyl)phthalide were determined by circular dichroism (CD) spectra. Among the isolated compounds, caulivotrioloxin A concentration-dependently decreased the cellular melanin contents and tyrosinase activities in mouse melanoma B16-F10 cells, suggesting the anti-melanogenic potentials. The anti-melanogenic effects of caulivotrioloxin A involved the decrease in the protein expressions of melanogenic enzymes, including tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. Taken together, these results suggested that the isolates from D. caulivora could be served as natural melanogenesis inhibitors for cosmeceutical applications.

Prinsepiae Nux Extract Activates NRF2 Activity and Protects UVB-Induced Damage in Keratinocyte

Ultraviolet B (UVB) is one of the most important environmental factors that cause extrinsic aging through increasing intracellular reactive oxygen species (ROS) production in the skin. Due to its protective roles against oxidative stress, nuclear factor erythroid-2-related factor (NRF2) has been traditionally considered as a target for skin aging prevention. Here, we identified the extract of Prinsepiae Nux, a top-grade drug listed in Shen Nong Ben Cao Jing, as a potent NRF2 activator by high-throughput screening. A bioassay-guided fractionation experiment revealed that NRF2-activating components were concentrated in the 90% methanol (MP) fraction. MP fraction significantly increased the expression of NRF2 and HO-1 protein and upregulated HO-1 and NQO1 mRNA expression in HaCaT cells. Moreover, MP fraction pre-treatment dramatically reversed UVB-induced depletion of NRF2 and HO-1, accumulation of intracellular ROS, NF-κB activation, and the upregulation of pro-inflammatory genes. Finally, the qualitative analysis using UPLC-tandem mass spectroscopy revealed the most abundant ion peak in MP fraction was identified as α-linolenic acid, which was further proved to activate NRF2 signaling. Altogether, the molecular evidence suggested that MP fraction has the potential to be an excellent source for the discovery of natural medicine to treat/prevent UVB-induced skin damage.

Preparatory Conditions Optimization and Characterization of Hierarchical Porous Carbon from Seaweed as Carbon-Precursor Using a Box-Behnken Design for Application of Supercapacitor

This study has developed an environmentally friendly, simple, and economical process by utilizing seaweed as a carbon precursor to prepare a hierarchical porous carbon for the application of a supercapacitor. In the carbonization process, the design of experiment (DOE) technology is used to obtain the optimal preparatory conditions with the best electrochemical properties for the electrode materials of supercapacitors. Without using strong acid and alkali solution of the green process, NaCl is used as the pore structure proppant of seaweed (SW) for carbonization to obtain hierarchical porous carbon material to improve the pore size distribution and surface area of the material. In the experiment of SW activation, the interaction between factors has been explored by the response surface methodology (RSM) and Box-Behnken design, and the optimal conditions are found. The activated carbon with the specific surface area of 603.7 m² g^-1 and its capacitance reaching 110.8 F g^-1 is successfully prepared. At a current density of 1 A g^-1, the material still retains 95.4% of the initial capacitance after 10,000 cycles of stability testing. The hierarchical porous carbon material prepared by the design of experiment planning this green process has better energy storage properties than supercapacitors made of traditional carbon materials.

Cryptocaryone Promotes ROS-Dependent Antiproliferation and Apoptosis in Ovarian Cancer Cells

Cryptocaryone (CPC) is a bioactive dihydrochalcone derived from Cryptocarya plants, and its antiproliferation was rarely reported, especially for ovarian cancer (OVCA). This study aimed to examine the regulation ability and mechanism of CPC on three histotypes of OVCA cells (SKOV3, TOV-21G, and TOV-112D). In a 24 h MTS assay, CPC showed antiproliferation effects to OVCA cells, i.e., IC50 values 1.5, 3, and 9.5 μM for TOV-21G, SKOV3, and TOV-112D cells. TOV-21G and SKOV3 cells showed hypersensitivity to CPC when applied for exposure time and concentration experiments. For biological processes, CPC stimulated the generation of reactive oxygen species and mitochondrial superoxide and promoted mitochondrial membrane potential dysfunction in TOV-21G and SKOV3 cells. Apoptosis was detected in OVCA cells through subG1 accumulation and annexin V staining. Apoptosis signaling such as caspase 3/7 activities, cleaved poly (ADP-ribose) polymerase, and caspase 3 expressions were upregulated by CPC. Specifically, the intrinsic and extrinsic apoptotic caspase 9 and caspase 8 were overexpressed in OVCA cells following CPC treatment. Moreover, CPC also stimulated DNA damages in terms of γH2AX expression and increased γH2AX foci. CPC also induced 8-hydroxy-2’-deoxyguanosine DNA damages. These CPC-associated principal biological processes were validated to be oxidative stress-dependent by N-acetylcysteine. In conclusion, CPC is a potential anti-OVCA natural product showing oxidative stress-dependent antiproliferation, apoptosis, and DNA damaging functions.

Different types of components obtained from Monascus purpureus with neuroprotective and anti-inflammatory potentials

The mold Monascus has been used as a natural food coloring agent and food additive for more than 1000 years in Asian countries. In Chinese herbology, it was also used for easing digestion and antiseptic effects. Through a thorough investigation of a citrinin-free strain: M. purpureus BCRC 38110, four azaphilones, three benzenoids, one benzofuranone, one 5',6'-dihydrospiro[isochromane-1,2'-pyran]-4'(3'H)-one derivative, two steroids, and six tetralones have been successfully identified. Among them, monapyridine A (1), monatetralones A-E (2-6), and monabenzofuranone (7) were first reported. Their structures were characterized by 1D and 2D NMR, UV, IR, and HRESIMS analyses. With a series of bioactivity screening, monascuspirolide B (14) and ergosterol peroxide (16) exhibited concentration-dependent attenuation of the paclitaxel-induced neurite damage of mouse dorsal root ganglion neurons. The interleukin (IL)-1β-induced release of inflammatory cytokines IL-8 and tumor necrosis factor (TNF)-α in human chondrosarcoma cells was inhibited by monapurpureusone (8) and monascuspirolide B (14). Altogether, M. purpureus BCRC 38110 possessed potentials as natural therapeutics against inflammatory osteoarthritis and paclitaxel-induced neurotoxicity.

Investigations into Chemical Components from Monascus purpureus with Photoprotective and Anti-Melanogenic Activities

Monascus species are asexually or sexually reproduced homothallic fungi that can produce a red colorant, specifically the so-called red yeast rice or Anka, which is used as a food ingredient in Asia. Traditional experiences of using Monascus for treating indigestion, enhancing blood circulation, and health remedies motivate us to investigate and repurpose Monascus-fermented products. Here, two new 5H-cyclopenta[c]pyridine type azaphilones, 5S,6S-monaspurpyridine A (1) and 5R,6R-monaspurpyridine A (2), two new xanthonoids, monasxanthones A and B (3 and 4), one new naphthalenone, monasnaphthalenone (5), and one new azaphilone, monapurpurin (6), along with two known compounds were isolated from the 70% EtOH extract of a citrinin-free domesticated strain M. purpureus BCRC 38110. The phytochemical properties of the xanthonoid and naphthalenone components were first identified from Monascus sp. differently from the representative ingredients of polyketide-derived azaphilones. UVB-induced cell viability loss and reactive oxygen species (ROS) overproduction in human keratinocytes were attenuated by monascuspirolide B (7) and ergosterol peroxide (8), indicating their photoprotective potentials. Ergosterol peroxide (8) decreased the melanin contents and tyrosinase activities of mouse melanocytes, depending on the concentration, suggesting their anti-melanogenic effects. In conclusion, six new and two known compounds were isolated from M. purpureus BCRC 38110, and two of them exhibited dermal protective activities. The results revealed the novel potential of M. purpureus for developing natural cosmeceutics against skin photoaging.

Cinnamtannin B1 attenuates rosacea-like signs via inhibition of pro-inflammatory cytokine production and down-regulation of the MAPK pathway

Background

Rosacea is a common inflammatory disease of facial skin. Dysregulation of innate immunity with enhanced inflammation and increased abundance of LL-37 at the epidermal site is a characteristic feature of rosacea. Cinnamtannin B1 (CB1) is a condensed tannin with anti-inflammatory and anti-microbial activities. The aims of the study were to evaluate the potential of CB1 as a therapy for rosacea and to characterize the potential mechanisms of action.

Methods

We intraperitoneally administered 20 mg/kg CB1 once daily for 2 days into the LL-37-induced mouse model of rosacea. The effects of CB1 in vivo were evaluated by the observations of lesions, histology, immunohistochemistry, and the transcription and translation of pro-inflammatory cytokines and chemokines. Human keratinocyte HaCaT and monocyte THP-1 were used to characterize the effects of CB1 on LL-37-induced inflammation in vitro. The changes in pro-inflammatory chemokine interleukin-8 (IL-8) were quantitated by enzyme-linked immunosorbent assay (ELISA), and the expressions of genes involved were determined by Western blotting.

Results

CB1 attenuated local redness, inflammation, and neutrophil recruitment in the mouse model of rosacea in vivo. CB1 suppressed myeloperoxidase (MPO) and macrophage inflammatory protein 2 (MIP-2) production, a functional homolog of interleukin-8 (IL-8), at the lesions. In vitro experiments confirmed that CB1 reversed the LL-37-induced IL-8 production in human keratinocytes HaCaT and monocyte THP-1 cells. CB1 inhibited IL-8 production through downregulating the phosphorylation of extracellular signal-regulated kinase (ERK) in the mitogen-activated protein kinase (MAPK) pathway.

Conclusion

CB1 attenuated LL-37-induced inflammation, specifically IL-8 production, through inhibiting the phosphorylation of ERK. CB1 has potential as a treatment for rosacea.

Phytochemical Investigation and Anti-Inflammatory Activity of the Leaves of Machilus japonica var. kusanoi

In a series of anti-inflammatory screenings of lauraceous plants, the methanolic extract of the leaves of Machilus japonica var. kusanoi (Hayata) J.C. Liao showed potent inhibition on both superoxide anion generation and elastase release in human neutrophils. Bioassay-guided fractionation of the leaves of M. japonica var. kusanoi led to the isolation of twenty compounds, including six new butanolides, machinolides A–F (1–6), and fourteen known compounds (7–20). Their structures were characterized by 1D and 2D NMR, UV, IR, CD, and MS data. The absolute configuration of the new compounds were unambiguously confirmed by single-crystal X-ray diffraction analyses (1, 2, and 3) and Mosher’s method (4, 5, and 6). In addition, lignans, (+)-eudesmin (11), (+)-methylpiperitol (12), (+)-pinoresinol (13), and (+)-galbelgin (16) exhibited inhibitory effects on N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation in human neutrophils with IC₅₀ values of 8.71 ± 0.74 μM, 2.23 ± 0.92 μM, 6.81 ± 1.07 μM, and 7.15 ± 2.26 μM, respectively. The results revealed the anti-inflammatory potentials of Formosan Machilus japonica var. kusanoi.

Anti-Inflammatory and Antibacterial Activity Constituents from the Stem of Cinnamomum validinerve

One new dibenzocycloheptene, validinol (1), and one butanolide firstly isolated from the natural source, validinolide (2), together with 17 known compounds were isolated from the stem of Cinnamomum validinerve. Among the isolates, lincomolide A (3), secosubamolide (7), and cinnamtannin B1 (19) exhibited potent inhibition on both superoxide anion generation (IC₅₀ values of 2.98 ± 0.3 µM, 4.37 ± 0.38 µM, and 2.20 ± 0.3 µM, respectively) and elastase release (IC₅₀ values of 3.96 ± 0.31 µM, 3.04 ± 0.23 µM, and 4.64 ± 0.71 µM, respectively) by human neutrophils. In addition, isophilippinolide A (6), secosubamolide (7), and cinnamtannin B1 (19) showed bacteriostatic effects against Propionibacterium acnes in in vitro study, with minimal inhibitory concentration (MIC) values at 16 μg/mL, 16 μg/mL, and 500 μg/mL, respectively. Further investigations using the in vivo ear P. acnes infection model showed that the intraperitoneal administration of the major component cinnamtannin B1 (19) reduced immune cell infiltration and pro-inflammatory cytokines TNF-α and IL-6 at the infection sites. The results demonstrated the potential of cinnamtannin B1 (19) for acne therapy. In summary, these results demonstrated the anti-inflammatory potentials of Formosan C. validinerve during bacterial infections.

Chemical Constituents with GNMT-Promoter-Enhancing and NRF2-Reduction Activities from Taiwan Agarwood Excoecaria formosana

Hepatocellular carcinoma (HCC) is considered to be a silent killer, and was the fourth leading global cause of cancer deaths in 2018. For now, sorafenib is the only approved drug for advanced HCC treatment. The introduction of additional chemopreventive agents and/or adjuvant therapies may be helpful for the treatment of HCC. After screening 3000 methanolic extracts from the Formosan plant extract bank, Excoecaria formosana showed glycine N-methyltransferase (GNMT)-promoter-enhancing and nuclear factor erythroid 2-related factor 2 (NRF2)-suppressing activities. Further, the investigation of the whole plant of E. formosana led to the isolation of a new steroid, 7α-hydroperoxysitosterol-3-O-β-d-(6-O-palmitoyl)glucopyranoside (1); two new coumarinolignans, excoecoumarin A (2) and excoecoumarin B (3); a new diterpene, excoeterpenol A (4); and 40 known compounds (5-44). Among them, Compounds 38 and 40-44 at a 100 μM concentration showed a 2.97 ± 0.27-, 3.17 ± 1.03-, 2.73 ± 0.23-, 2.63 ± 0.14-, 6.57 ± 0.13-, and 2.62 ± 0.05-fold increase in GNMT promoter activity, respectively. In addition, Compounds 40 and 43 could reduce NRF2 activity, a transcription factor associated with drug resistance, in Huh7 cells with relative activity of 33.1 ± 0.2% and 45.2 ± 2.5%. These results provided the basis for the utilization of Taiwan agarwood for the development of anti-HCC agents.

Ascleposide, a natural cardenolide, induces anticancer signaling in human castration-resistant prostatic cancer through Na+ /K+ -ATPase internalization and tubulin acetylation

BACKGROUND

Cardiac glycosides, which inhibit Na⁺ /K⁺ -ATPase, display inotropic effects for the treatment of congestive heart failure and cardiac arrhythmia. Recent studies have suggested signaling downstream of Na⁺ /K⁺ -ATPase action in the regulation of cell proliferation and apoptosis and have revealed the anticancer activity of cardiac glycosides. The study aims to characterize the anticancer potential of ascleposide, a natural cardenolide, and to uncover its primary target and underlying mechanism against human castration-resistant prostate cancer (CRPC).

METHODS

Cell proliferation was examined in CRPC PC-3 and DU-145 cells using sulforhodamine B assay, carboxyfluorescein succinimidyl ester staining assay and clonogenic examination. Flow cytometric analysis was used to detect the distribution of cell cycle phase, mitochondrial membrane potential, intracellular Na⁺ and Ca²⁺ levels, and reactive oxygen species production. Protein expression was examined using Western blot analysis. Endocytosis of Na⁺ /K⁺ -ATPase was determined using confocal immunofluorescence microscopic examination.

RESULTS

Ascleposide induced an increase of intracellular Na⁺ and a potent antiproliferative effect. It also induced a decrease of G1 phase distribution while an increase in both G2/M and apoptotic sub-G1 phases, and downregulated several cell cycle regulator proteins, including cyclins, Cdk, p21, and p27 Cip/Kip proteins, Rb and c-Myc. Ascleposide decreased the expression of antiapoptotic Bcl-2 members (eg, Bcl-2 and Mcl-1) but upregulated proapoptotic member (eg, Bak), leading to a significant loss of mitochondrial membrane potential and activation of both caspase-9 and caspase-3. Ascleposide also dramatically induced tubulin acetylation, leading to inhibition of the catalytic activity of Na⁺ /K⁺ -ATPase. Notably, extracellular high K⁺ (16 mM) significantly blunted ascleposide-mediated effects. Furthermore, ascleposide induced a p38 MAPK-dependent endocytosis of Na⁺ /K⁺ -ATPase and downregulated the protein expression of Na⁺ /K⁺ -ATPase α1 subunit.

CONCLUSION

Ascleposide displays antiproliferative and apoptotic activities dependent on the inhibition of Na⁺ /K⁺ -ATPase pumping activity through p38 MAPK-mediated endocytosis of Na⁺ /K⁺ -ATPase and downregulation of α1 subunit, which in turn cause tubulin acetylation and cell cycle arrest. Cell apoptosis is ultimately triggered by the activation of caspase cascade attributed to mitochondrial damage through the downregulation of Bcl-2 and Mcl-1 protein expressions while upregulation of Bak protein levels. The data also suggest the potential of ascleposide in anti-CRPC development.

Avocado (Persea americana) fruit extract (2R,4R)-1,2,4-trihydroxyheptadec-16-yne inhibits dengue virus replication via upregulation of NF-κB-dependent induction of antiviral interferon responses

Dengue virus (DENV) caused millions of infections around the world annually. Co-infection with different serotypes of DENV is associated with dengue hemorrhagic shock syndrome, leading to an estimate of 50% death rate. No approved therapies are currently available for the treatment of DENV infection. Hence, novel anti-DENV agents are urgently needed for medical therapy. Here we demonstrated that a natural product (2 R,4 R)-1,2,4-trihydroxyheptadec-16-yne (THHY), extracted from avocado (Persea americana) fruit, can inhibit DENV-2 replication in a concentration-dependent manner and efficiently suppresses replication of all DENV serotypes (1–4). We further reveal that the NF-κB-mediated interferon antiviral response contributes to the inhibitory effect of THHY on DENV replication. Using a DENV-infected ICR suckling mouse model, we found that THHY treatment caused an increased survival rate among mice infected with DENV. Collectively, these findings support THHY as a potential agent to control DENV infection.

Two New Abietane-type Diterpenes from the Bark of Cryptomeria japonica

Phytochemical investigation of the methanol extract of the bark of Cryptomeria japonica has led to the isolation of two new abietane-type diterpenoids, 7a-(2’-butoxyethoxy)deoxocryptojaponol (1) and 7p-(2’-butoxyethoxy)deoxocryptojaponol (2). Their structures were established by means of 1D and 2D NMR spectra and HR-EI-MS, as well as on comparison with the reported data.

Identification of anti-viral activity of the cardenolides, Na+/K+-ATPase inhibitors, against porcine transmissible gastroenteritis virus

A series of naturally occurring cardenolides that exhibit potent anti-transmissible gastroenteritis virus (TGEV) activity in swine testicular (ST) cells has been identified. In an immunofluorescence assay, these cardenolides were found to diminish the expressions of TGEV nucleocapsid and spike protein, which was used as an indication for viral replication; block TGEV infection induced apoptosis and cytopathic effects; and impart the same trend of inhibitory activity against Na⁺/K⁺-ATPase as for anti-TGEV activity. The viral titer inhibition was found to take place in a dose-dependent manner. Knocking down expression of Na⁺/K⁺-ATPase, the cellular receptor of cardenolides, in ST cells was found to significantly impair the susceptibility of ST cells to TGEV infectivity. Thus, we have identified Na⁺/K⁺-ATPase as an anti-viral drug target and its antagonists, cardenolides, a novel class of anti- TGEV agents.

Bioactive composition of Reevesia formosana root and stem with cytotoxic activity potential

Three lignanoids and three terpenoids, along with 40 known compounds were isolated from Reevesia formosana.

Attenuation of antigen-specific T helper 1 immunity by Neolitsea hiiranensis and its derived terpenoids

Background

T cells play a pivotal role in the adaptive immunity that participates in a wide range of immune responses through a complicated cytokine network. Imbalance of T-cell responses is involved in several immune disorders. Neolitsea species, one of the biggest genera in the family Lauraceae, have been employed widely as folk medicines for a long time in Asia. Previous phytochemical investigations revealed the abundance of terpenes in the leaves of N. hiiranensis, an endemic Neolitsea in Taiwan, and demonstrated anti-inflammatory activities. However, the effect of N. hiiranensis on the functionality of immune cells, especially T cells, is still unclear. In this study, we utilize in vitro and in vivo approaches to characterize the effects of leaves of N. hiiranensis and its terpenoids on adaptive immune responses.

Methods

Dried leaves of N. hiiranensis were extracted three times with cold methanol to prepare crude extracts and to isolate its secondary metabolites. The ovalbumin (OVA)-sensitized BALB/c mice were administrated with N. hiiranensis extracts (5–20 mg/kg). The serum and splenocytes of treated mice were collected to evaluate the immunomodulatory effects of N. hiiranensis on the production of OVA-specific antibodies and cytokines. To further identify the N. hiiranensis-derived compounds with immunomodulatory potentials, OVA-primed splenocytes were treated with compounds isolated from N. hiiranensis by determining the cell viability, cytokine productions, and mRNA expression in the presence of OVA in vitro.

Results

Crude extracts of leaves of N. hiiranensis significantly inhibited IL-12, IFN-γ, and IL-2 cytokine productions as well as the serum levels of antigen-specific IgM and IgG_2ain vivo. Two of fourteen selected terpenoids and one diterpenoid derived from the leaves of N. hiiranensis suppressed IFN-γ in vitro. In addition, β-caryophyllene oxide attenuated the expression of IFN-γ, T-bet, and IL-12Rβ2 in a dose-dependent manner. N. hiiranensis-derived β-caryophyllene oxide inhibited several aspects of adaptive immune responses, including T-cell differentiation, IFN-γ production, and Th1-assocaited genes.

Conclusion

As IFN-γ is the key cytokine secreted by T helper-1 cells and plays a pivotal role in Th1 immune responses, our results suggested that the N. hiiranensis and its terpenoids may possess potential therapeutic effects on Th1-mediated immune disorders.

Cytotoxic cardenolides and sesquiterpenoids from the fruits of Reevesia formosana

Bioassay-guided fractionation of the fruits of Reevesia formosana led to isolation of three cardenolides (reevesioside J, reevesioside K, and epi-reevesioside K), three sesquiterpenoids (reevesiterpenol C, reevesiterpenol D, and reevesiterpenol E), and two glycosides (reevesianin A and reevesianin B), along with 46 known compounds. Their structures were determined using spectroscopic techniques. In addition to the reported cytotoxic cardenolides, reevesioside J and strophanthidin exhibited moderate cytotoxicity against the cell lines MCF-7, NCI-H460, and HepG2, with IC50 values of 0.39 ± 0.06 μM and 1.06 ± 0.12 μM for MCF-7, 0.12 ± 0.01 μM and 0.29 ± 0.01 μM for NCI-H460, and 1.09 ± 0.02 μM and 1.72 ± 0.02 μM for HepG2, respectively. Reevesiterpenol E also exhibited the best selective cytotoxicity to the NCI-H460 cell line, with an IC50 value of 3.15 ± 0.22 μM.

Sesquiterpenoids and Diterpenoids from the Wood of Cunninghamia konishii and Their Inhibitory Activities against NO Production

Three new sesquiterpenoids, 2α-hydroxy-3,3,6α,9β-tetramethyltricyclo[4,3,2(1,4)]undecane (1), 11-acetoxyeudesman-4β-ol (4), and 2α,3β-dihydroxy-4β-methyl-6,8,10-cadinatriene (6), four known sesquiterpenoids (2, 3, 5, and 7), together with eight known diterpenoids (8-15), were isolated from the wood of Cunninghamia konishii. Their structures were determined by detailed analysis of spectroscopic data and comparison with the data of known analogues. Four sesquiterpenoids (1, 4, 5, and 6) and all the diterpenoids (8-15) were evaluated for inhibition of nitric oxide production in lipopolysaccharides (LPS)-activated RAW 264.7 macrophages and the results showed that compounds 10 and 15 exhibited moderate inhibitory activities against nitric oxide production.

Chemical constituents and bioactivity of Formosan lauraceous plants

Taiwan is rich in lauraceous plants. A review of 197 references based on the chemical analysis and bioactivity of indigenous lauraceous plants carried out by native scientists from 1963 to 2014 has been compiled. About 303 new compounds and thousands of known compounds comprising alkaloids and non-alkaloids with diverse structures have been isolated or identified from indigenous plants belonging to the 11 lauraceous genera. The volatile components, however, have been excluded from this review. This review provides an overview of the past efforts of Taiwan scientists working on secondary metabolites and their bioactivity in native lauraceous plants. The potential of lauraceous plants worthy of further study is also noted. The contents will be helpful for the chemotaxonomy of Lauraceae and be of value for the development of native Formosan lauraceous plants.

Antiproliferation of Cryptocarya concinna-derived cryptocaryone against oral cancer cells involving apoptosis, oxidative stress, and DNA damage

Background

Cryptocarya-derived crude extracts and their compounds have been reported to have an antiproliferation effect on several types of cancers but their impact on oral cancer is less well understood.

Methods

We examined the cell proliferation effect and mechanism of C. concinna-derived cryptocaryone (CPC) on oral cancer cells in terms of cell viability, apoptosis, reactive oxygen species (ROS), mitochondrial depolarization, and DNA damage.

Results

We found that CPC dose-responsively reduced cell viability of two types of oral cancer cells (Ca9-22 and CAL 27) in MTS assay. The CPC-induced dose-responsive apoptosis effects on Ca9-22 cells were confirmed by flow cytometry-based sub-G1 accumulation, annexin V staining, and pancaspase analyses. For oral cancer Ca9-22 cells, CPC also induced oxidative stress responses in terms of ROS generation and mitochondrial depolarization. Moreover, γH2AX flow cytometry showed DNA damage in CPC-treated Ca9-22 cells. CPC-induced cell responses in terms of cell viability, apoptosis, oxidative stress, and DNA damage were rescued by N-acetylcysteine pretreatment, suggesting that oxidative stress plays an important role in CPC-induced death of oral cancer cells.

Conclusions

CPC is a potential ROS-mediated natural product for anti-oral cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1073-5) contains supplementary material, which is available to authorized users.

Synergistic anti-oral cancer effects of UVC and methanolic extracts of Cryptocarya concinna roots via apoptosis, oxidative stress and DNA damage

Purpose Radiation combined with natural products may improve the radiosensitivity of cancer cells. This study investigated the potential of a combined modality treatment with Ultraviolet C (UVC; wavelength range 200-280 nm) and our previously identified anti-oral cancer agent (methanolic extracts of Cryptocarya concinna roots; MECCrt) in oral cancer cells. Materials and methods The mechanism of the possible synergy of UVC and MECCrt was explored in terms of cell viability, cell cycle, apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MitoMP), and DNA damage analyses. Results In cell viability (%) at 24 h treatment, the low doses of UVC (14 J/m(2)) and MECCrt (10 μg/ml) resulted in slight damage to human oral cancer Ca9-22 cells (83.2 and 80.4) but was less harmful to human oral normal HGF-1 cells (93.4 and 91.8, respectively). The combined treatment of UVC and MECCrt (UVC/MECCrt) had a lower viability (54.5%) than UVC or MECCrt alone in Ca9-22 cells but no showed significant change in HGF-1 cells. In Ca9-22 cells, the expression of flow cytometry-based apoptosis (sub-G1 phase, annexin V, and pancaspase assays) was significantly higher in UVC/MECCrt than in UVC or MECCrt alone (p < 0.0001). Using flow cytometry, intracellular ROS levels of UVC/MECCrt and MECCrt alone were higher than for UVC alone. MitoMP change and H2A histone family member X (γH2AX; H2AFX)-based DNA damage were synergistically inhibited and induced by MECCrt/UVC compared to its single treatment in Ca9-22 cells, respectively. Conclusion UVC plus MECCrt treatment had selective killing and synergistic anti-proliferative effects against oral cancer cells involving apoptosis, oxidative stress, and DNA damage. This combination therapy appears to have a great clinical potential against oral cancer cells.

Discovery of selective inhibitors of Glutaminase-2, which inhibit mTORC1, activate autophagy and inhibit proliferation in cancer cells

Glutaminase, which converts glutamine to glutamate, is involved in Warburg effect in cancer cells. Two human glutaminase genes have been identified, GLS (GLS1) and GLS2. Two alternative transcripts arise from each glutaminase gene: first, the kidney isoform (KGA) and glutaminase C (GAC) for GLS; and, second, the liver isoform (LGA) and glutaminase B (GAB) for GLS2. While GLS1 is considered as a cancer therapeutic target, the potential role of GLS2 in cancer remains unclear. Here, we discovered a series of alkyl benzoquinones that preferentially inhibit glutaminase B isoform (GAB, GLS2) rather than the kidney isoform of glutaminase (KGA, GLS1). We identified amino acid residues in an allosteric binding pocket responsible for the selectivity. Treatment with the alkyl benzoquinones decreased intracellular glutaminase activity and glutamate levels. GLS2 inhibition by either alkyl benzoquinones or GLS2 siRNA reduced carcinoma cell proliferation and anchorage-independent colony formation, and induced autophagy via AMPK mediated mTORC1 inhibition. Our findings demonstrate amino acid sequences for selective inhibition of glutaminase isozymes and validate GLS2 as a potential anti-cancer target.

Biological evaluation of secondary metabolites from the root of Machilus obovatifolia

Bioassay-guided fractionation of the root of Machilus obovatifolia led to the isolation of four new lignans, epihenricine B (1), threo-(7'R,8'R) and threo-(7'S,8'S)-methylmachilusol D (2 and 3), and isofragransol A (4), along with 23 known compounds. The compounds were obtained as isomeric mixtures (i.e., 2/3 and 4/20, resp.). The structures were elucidated by spectral analyses. Among the isolates, 1, licarin A (12), guaiacin (14), (±)-syringaresinol (21), and (-)-epicatechin (23) showed ABTS (=2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical-scavenging activity, with SC50 values of 11.7±0.5, 12.3±1.1, 11.0±0.1, 10.6±0.3, and 9.5±0.2 μM in 20 min, respectively. In addition, kachirachirol B (17) showed cytotoxicity against the NCI-H460 cell line with an IC50 value of 3.1 μg/ml.

New Furanone and Sesquiterpene from the Pericarp of Calocedrus formosana

One new γ-lactone, namely calolactone (1), together with one new drimane-type sesquiterpene, namely caloterpene (2), were isolated from the pericarp of Calocedrus formosana Florin. Their structures were elucidated by spectroscopic and mass spectrometric analysis.