Pectolinarigenin Research Articles

Pharmacokinetic and tissue distribution study of pectolinarigenin in rats using UPLC-MS/MS

Pectolinarigenin (PEC), a natural flavonoid isolated from Cirsium japonicum, exhibits promising therapeutic potential for multiple cancers. In present study, a simple and sensitive UPLC-MS/MS method was established for the quantification of PEC in rat plasma and tissues. The assay procedure involved a one-step protein precipitation with tadalafil as the internal standard, and separation on a Welch Xtimate UHPLC C18 column by gradient elution of acetonitrile/aqueous formic acid (0.1 %, v/v) at a flow rate of 0.2 m L·min−1. The detection was conducted using multiple-reaction monitoring via an electrospray ionization source in positive ionization mode. The established method was proved to be highly sensitive with a good linearity (R2 > 0.99) in respective concentration range (0.1–100 ng·mL−1 in plasma and 1–10,000 ng·mL−1 in tissues) and acceptable extraction recovery (≥71.17 %), matrix effect and stability, which was applied to study the pharmacokinetics and tissue distribution of PEC after intravenous (100 μg·kg−1) and oral administration (10, 20 and 40 mg·kg−1). PEC was promptly absorbed (Tmax ≤ 0.222 h) and maintained at a low level with slow elimination (t1/2 z ≥ 14.47 h) in rats after oral administration, resulting in extremely low bioavailability (0.56–0.68 %). However, PEC is widely distributed in rat tissues with high exposure in GI tract, liver and kidney. The bioavailability and tissue affinity were firstly revealed, which would guide directions for further development of PEC as an anti-tumor drug candidate.

Pectolinarigenin ameliorated airway inflammation and airway remodeling to exhibit antitussive effect.

Cough is a common symptom of several respiratory diseases. However, frequent coughing from acute to chronic often causes great pain to patients. It may turn into cough variant asthma, which seriously affects people's quality of life. For cough treatment, it is dominated by over-the-counter antitussive drugs, such as asmeton, but most currently available antitussive drugs have serious side effects. Thus, there is a great need for the development of new drugs with potent cough suppressant. BALB/c mice were used to construct mice model with cough to investigate the pharmacological effects of pectolinarigenin (PEC). Hematoxylin-eosin and Masson staining were used to assess lung injury and airway remodeling, and ELISA was used to assess the level of inflammatory factor release. In addition, inflammatory cell counts were measured to assess airway inflammation. Airway hyperresponsiveness assay was used to assess respiratory resistance in mice. Finally, we used Western blotting to explore the potential mechanisms of PEC. We found that PEC could alleviate lung tissue injury and reduce the release of inflammatory factors, inhibit of cough frequency and airway wall collagen deposition in mice model with cough. Meanwhile, PEC inhibited the Ras/ERK/c-Fos pathway to exhibit antitussive effect. Therefore, PEC may be a potential drug for cough suppression.

Pectolinarigenin ameliorates osteoporosis via enhancing Wnt signaling cascade in PPARβ-dependent manner

BackgroundOsteoporosis is a prevalent metabolic bone disease in older adults. Peroxisome proliferator-activated receptor β (PPARβ), the most abundant PPAR isotype expressed in bone tissues, plays a critical role in regulating the energy metabolism of osteoblasts. However, the botanical compounds targeting PPARβ for the treatment of osteoporosis remain largely unexplored. PurposeTo discover a potent PPARβ agonist from botanical compounds, as well as to investigate the anti-osteoporosis effects and to elucidate the underlying mechanisms of the newly identified PPARβ agonist. MethodsThe PPARβ agonist effects of botanical compounds were screened by an in vitro luciferase reporter gene assay. The PPARβ agonist effects of pectolinarigenin (PEC) in bone marrow mesenchymal stromal cells (BMSCs) were validated by Western blotting. RNA-seq transcriptome analyses were conducted to reveal the underlying osteoporosis mechanisms of PEC in BMSCs. The PPARβ antagonist (GSK0660) and Wnt signaling inhibitor (XAV969) were used to explore the role of the PPARβ and Wnt signaling cascade in the anti-osteoporosis effects of PEC. PEC or the PEG-PLGA nanoparticles of PEC (PEC–NP) were intraperitoneally administrated in both wild-type mice and ovariectomy-induced osteoporosis mice to examine its anti-osteoporotic effects in vivo. ResultsPEC, a newly identified naturally occurring PPARβ agonist, significantly promotes osteogenic differentiation and up-regulates the osteogenic differentiation-related genes (Runx2, Osterix, and Bmp2) in BMSCs. RNA sequencing and functional gene enrichment analysis suggested that PEC could activate osteogenic-related signaling pathways, including Wnt and PPAR signaling pathways. Further investigations suggested that PEC could enhance Wnt/β-catenin signaling in a PPARβ-dependent manner in BMSCs. Animal tests showed that PEC–NP promoted bone mass and density, increased the bone cell matrix protein, and accelerated bone formation in wild-type mice, while PEC–NP also played a preventive role in ovariectomy-induced osteoporosis mice via maintaining the expression level of bone cell matrix protein, balancing the rate of bone formation, and slowing down bone loss. Additionally, PEC–NP did not cause any organ injury and body weight loss after long-term use (11 weeks). ConclusionPEC significantly promotes bone formation and reduces bone loss in both BMSCs and ovariectomy-induced osteoporosis mice via enhancing the Wnt signaling cascade in a PPARβ-dependent manner, providing a new alternative therapy for preventing estrogen deficiency-induced osteoporotic diseases.

Pectolinarigenin Improves Oxidative Stress and Apoptosis in Mouse NSC-34 Motor Neuron Cell Lines Induced by C9-ALS-Associated Proline-Arginine Dipeptide Repeat Proteins by Enhancing Mitochondrial Fusion Mediated via the SIRT3/OPA1 Axis.

Amyotrophic lateral sclerosis (ALS) is considered a fatal progressive degeneration of motor neurons (MN) caused by oxidative stress and mitochondrial dysfunction. There are currently no treatments available. The most common inherited form of ALS is the C9orf72 mutation (C9-ALS). The proline-arginine dipeptide repeat protein (PR-DPR) produced by C9-ALS has been confirmed to be a functionally acquired pathogenic factor that can cause increased ROS, mitochondrial defects, and apoptosis in motor neurons. Pectolinarigenin (PLG) from the traditional medicinal herb Linaria vulgaris has antioxidant and anti-apoptotic properties. I established a mouse NSC-34 motor neuron cell line model expressing PR-DPR and confirmed the neuroprotective effect of PLG. The results showed that ROS production and apoptosis caused by PR-DPR could be improved by PLG treatment. In terms of mechanism research, PR-DPR inhibited the activity of the mitochondrial fusion proteins OPA1 and mitofusin 2. Conversely, the expression of fission protein fission 1 and dynamin-related protein 1 (DRP1) increased. However, PLG treatment reversed these effects. Furthermore, I found that PLG increased the expression and deacetylation of OPA1. Deacetylation of OPA1 enhances mitochondrial fusion and resistance to apoptosis. Finally, transfection with Sirt3 small interfering RNA abolished the neuroprotective effects of PLG. In summary, the mechanism by which PLG alleviates PR-DPR toxicity is mainly achieved by activating the SIRT3/OPA1 axis to regulate the balance of mitochondrial dynamics. Taken together, the potential of PLG in preclinical studies for C9-ALS drug development deserves further evaluation.

Characterization of the glucuronidating pathway of pectolinarigenin, the major active constituent of the Chinese medicine Daji, in humans and its influence on biological activities

Ethnopharmacological relevanceThe Chinese medicine Daji (the aerial part of Cirsium japonicum DC.) and its charred product (Cirsii Japonici Herba Carbonisata) have been widely used as hemostatic agents or diuretic agents to prepare a variety of Chinese herbal formula. Pectolinarigenin (PEC), one of the most abundant constituents in both Daji and its charred product, has been considered as the key effective substance responsible for the major pharmacological activities of Daji, including hemostasis, hepatoprotective, anti-tumor and anti-osteoporosis effects. However, the major metabolic pathways of PEC in humans and the influence of PEC metabolism on its biological activities are poorly understood. Aim of the studyTo characterize the main metabolic pathway(s) and key enzymes of PEC in human biological systems, as well as to reveal the influence of PEC metabolism on its biological activities. Materials and methodsThe metabolic stability assays of PEC were investigated in human liver microsomes (HLM). The O-glucuronide of PEC was biosynthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy. The key enzymes responsible for O-glucuronidation of PEC in humans were assigned by performing UGT reaction phenotyping, chemical inhibition and enzymatic kinetic assays. The agonist effects of PEC and its O-glucuronide on nuclear factor erythroid2-related factor 2 (Nrf2), Peroxisome proliferator activated receptors (PPARα and PPARβ) were tested at the cellular level. ResultsPEC could be readily metabolized to form a mono-O-glucuronide in both human liver microsome (HLM) and human intestinal microsome (HIM). The mono-O-glucuronide was bio-synthesized by mouse liver S9 and its structure was fully characterized as PEC-7-O-β-D-glucuronide (PEC-O-7-G). UGT1A1, UGT1A3 and UGT1A9 are key enzymes responsible for PEC-7-O-glucuronidation in HLM, while UGT1A1, UGT1A9 and 1A10 may play key roles in this reaction in HIM. Biological tests revealed that PEC displayed strong agonist effects on Nrf2, PPARα and PPARβ, whereas PEC-7-O-glucuronide showed relatively weak Nrf2 agonist effect and very weak PPAR agonist effects, indicating that PEC-7-O-glucuronidation strongly weaken its agonist effects on Nrf2 and PPAR. ConclusionsOur results demonstrate that 7-O-glucuronidation is the major metabolic pathway of PEC in human tissues, while UGT1A1, 1A3 and 1A9 are key contributing enzymes responsible for PEC-7-O-glucuronidation in human liver. It is also found that PEC 7-O-glucuronidation significantly weakens the Nrf2 and PPAR agonist effects. All these findings are very helpful for the pharmacologists to deep understand the metabolic rates of PEC in humans.

Pectolinarigenin inhibits bladder urothelial carcinoma cell proliferation by regulating DNA damage/autophagy pathways

Pectolinarigenin (PEC), an active compound isolated from traditional herbal medicine, has shown potential anti-tumor properties against various types of cancer cells. However, its mechanism of action in bladder cancer (BLCA), which is one of the fatal human carcinomas, remains unexplored. In this study, we first revealed that PEC, as a potential DNA topoisomerase II alpha (TOP2A) poison, can target TOP2A and cause significant DNA damage. PEC induced G2/M phase cell cycle arrest via p53 pathway. Simultaneously, PEC can perform its unique function by inhibiting the late autophagic flux. The blocking of autophagy caused proliferation inhibition of BLCA and further enhanced the DNA damage effect of PEC. In addition, we proved that PEC could intensify the cytotoxic effect of gemcitabine (GEM) on BLCA cells in vivo and in vitro. Summarily, we first systematically revealed that PEC had great potential as a novel TOP2A poison and an inhibitor of late autophagic flux in treating BLCA.

Pectolinarigenin ameliorates acetaminophen-induced acute liver injury via attenuating oxidative stress and inflammatory response in Nrf2 and PPARa dependent manners

BackgroundCirsii Japonici Herba Carbonisata (Dajitan in Chinese) has been used to treat liver disorders in Asian countries. Pectolinarigenin (PEC), an abundant constituent in Dajitan, has been found to possess a wide range of biological benefits, including hepatoprotective effects. However, the effects of PEC on acetaminophen (APAP)-induced liver injury (AILI) and the underlying mechanisms have not been studied. PurposesTo explore the role and mechanisms of PEC in protecting against AILI. Study design and methodsThe hepatoprotective benefits of PEC were studied using a mouse model and HepG2 cells. PEC was tested for its effects by injecting it intraperitoneally before APAP administration. To assess liver damage, histological and biochemical tests were performed. The levels of inflammatory factors in the liver were measured using RT-PCR and ELISA. Western blotting was used to measure the expression of a panel of key proteins involved in APAP metabolism, as well as Nrf2 and PPARα. PEC mechanisms on AILI were investigated using HepG2 cells, while the Nrf2 inhibitor (ML385) and PPARα inhibitor (GW6471) were used to validate the importance of either Nrf2 and PPARα in the hepatoprotective effects of PEC. ResultsPEC treatment decreased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) levels in the liver. PEC pretreatment increased the activity of superoxide dismutase (SOD) and glutathione (GSH) while decreasing malondialdehyde production (MDA). PEC could also up-regulate two important APAP detoxification enzymes (UGT1A1 and SULT1A1). Further research revealed that PEC reduced hepatic oxidative damage and inflammation, and up-regulated APAP detoxification enzymes in hepatocytes by activating the Nrf2 and PPARα signaling pathways. ConclusionsPEC ameliorates AILI by decreasing hepatic oxidative stress and inflammation while increasing phase Ⅱ detoxification enzymes related to APAP harmless metabolism through activation of Nrf2 and PPARα signaling. Hence, PEC may serve as a promising therapeutic drug against AILI.

Pectolinarigenin Suppresses LPS-Induced Inflammatory Response in Macrophages and Attenuates DSS-Induced Colitis by Modulating the NF-κB/Nrf2 Signaling Pathway.

Pectolinarigenin (PEC), a natural flavonoid present in cirsium chanroenicum and citrus fruits, has possess the distinct pharmacological activities. However, its molecular mechanisms and pharmacological effects on intestinal illness have not been elucidated. In the present study, we investigated the potential beneficial effects of pectolinarigenin (PEC) on lipopolysaccharide (LPS)-induced macrophage cells and the dextran sulfate sodium (DSS)-induced colitis model. Our findings showed that PEC pretreatment inhibits the LPS-induced nuclear factor-kappa B (NF-κB) activation by interfering with the degradation of IκB-α. Further, increased Nrf2 protein expression was reported on PEC treated RAW 264.7 and THP1 cell lines. In addition, we revealed that PEC mediated the NF-κB/Nrf2 pathway regulation, which in turn inhibits the synthesis of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), interleukin-1beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) on RAW 264.7 and THP1 cells. Furthermore, PEC dose-dependently reduced the DSS-induced inflammation in the colon by regulating NF-κB/Nrf2 signaling pathway and enhancing the myeloperoxidase (MPO) activity and redox regulators such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and lipid peroxidation byproduct malondialdehyde (MDA) in DSS-induced inflamed colon. Similarly, we reported the minimal pathological damages in the PEC-treated mice colon, as well as increase goblet cell population and mucin-2 production. In conclusion, our findings demonstrate that PEC reduces the DSS-induced colitis in mice by regulating the NF-κB/Nrf2 pathway. Thus, PEC might be a promising therapeutic agent for the treatment of inflammatory bowel disease.

Pectolinarigenin Induces Antioxidant Enzymes through Nrf2/ARE Pathway in HepG2 Cells.

Pectolinarigenin (PG) and its glycoside pectolinarin (PN) were reported to have various health beneficial functions such as anti-inflammatory and anti-carcinogenic activities. It has also been reported that PG and PN have radical scavenging ability as direct antioxidant activity. However, the indirect antioxidant activity of PG and PN by inducing antioxidant enzymes in hepatocytes is not fully understood yet. In this study, we investigated whether PG and PN increase expression of antioxidant enzymes through the nuclear factor-erythroid-2-related factor 2 (Nrf2)-mediated pathway in human hepatoma HepG2 cells and the liver of male ICR mice. PG, but not PN, induced antioxidant enzymes, namely heme oxigenase-1, NAD(P)H:quinone oxidoreductase 1, and aldo-keto reductase family 1 member B10, in HepG2 cells. As for the induction mechanism of these enzymes, PG-induced nuclear accumulation of Nrf2 increased antioxidant response element (ARE)-mediated transcriptional activity and suppressed degradation of Nrf2 through modification of Kelch-like EXH-associated protein 1. Oral administration of PG also induced nuclear accumulation Nrf2 and expression of antioxidant enzymes in the liver of mice. Therefore, PG, but not PN, exhibits the indirect antioxidant activity by inducing antioxidant enzymes through the Nrf2/ARE pathway and may protect liver from oxidative stress.

Natural Flavonoid Pectolinarigenin Alleviated Hyperuricemic Nephropathy via Suppressing TGFβ/SMAD3 and JAK2/STAT3 Signaling Pathways.

Natural flavonoid pectolinarigenin (PEC) was reported to alleviate tubulointerstitial fibrosis of unilateral ureteral obstruction (UUO) mice in our previous study. To further investigate nephroprotective effects of PEC in hyperuricemic nephropathy (HN), adenine and potassium oxonate induced HN mice and uric acid-treated mouse kidney epithelial (TCMK-1) cells were employed in the study. As a result, PEC significantly lowered serum uric acid level and restored hyperuricemia-related kidney injury in HN mice. Meanwhile, PEC alleviated inflammation, fibrosis, and reduced adipokine FABP4 content in the kidneys of HN mice and uric acid-treated TCMK-1 cells. Mechanistically, PEC inhibited the TGF-β1 expression as well as the phosphorylation of transcription factor SMAD3 and STAT3 to regulate the corresponding inflammatory and fibrotic gene expression in kidney tissues. In conclusion, our results suggested that PEC could inhibit the activation of SMAD3 and STAT3 signaling to suppress inflammation and fibrosis, and thereby alleviate HN in mice.

Neuroprotective and anti-inflammatory effect of pectolinarigenin, a flavonoid from Amazonian Aegiphila integrifolia (Jacq.), against lipopolysaccharide-induced inflammation in astrocytes via NFκB and MAPK pathways

Neurodegenerative diseases affect millions of people worldwide. Regardless of the underlying cause, neuroinflammation is the greatest risk factor for developing any of these disorders. Pectolinarigenin (PNG) is an active flavonoid with several biological properties, anti-metastatic and anti-inflammatory activity. This study investigate the biological effects of PNG in macrophage and astrocyte cultures, with focus on elucidating the molecular mechanisms involved in the PNG activity. J774A.1 murine macrophage or cerebral cortex primary astrocytes primary cultures were treated with different concentration of PNG (1–160 μM) and the inflammatory process was stimulated by LPS (1 μg/ml) and the effect of PNG in different inflammatory markers were determined. PNG did not affect astrocyte or macrophage viability. Moreover, this flavonoid reduced NO• release in macrophages, attenuated astrocyte activation by preventing the overexpression of glial fibrillary acidic protein, and decreased the release of inflammatory mediators, IL-1β and IL-6 induced by LPS by the glial cell, as well as enhanced basal levels of IL-10. In addition, PNG suppressed NFκB, p38MAPK and ERK1/2 phosphorylation in astrocytes culture induced by LPS. The results show clear evidence that this novel flavonoid protects astrocytes against LPS-induced inflammatory toxicity. In conclusion, PNG presents neuroprotective and anti-inflammatory property through the inhibition of inflammatory signaling pathways.

Natural flavonoid pectolinarigenin alleviated kidney fibrosis via inhibiting the activation of TGFβ/SMAD3 and JAK2/STAT3 signaling

Renal fibrosis is a final common manifestation of CKD resulting in progressive loss of kidney function. The activation of SMAD3 and STAT3 played central roles in the pathogenesis of renal fibrosis, which has been recognized as potential targets for antifibrotic therapy. As we known, the potential of natural products as the candidates for drug discovery has been well recognized. Here, we identified that pectolinarigenin (PEC), as a natural flavonoid and a reported STAT3 inhibitor, dose-dependently suppressed TGFβ/SMADs activity in HEK293 cells by luciferase reporter assay. In TGFβ1-stimulated NRK-49F fibroblast, PEC blocked the phosphorylation of SMAD3 and STAT3, and downregulated the major fibrotic gene and protein expression of TGFβ, α-SMA, COL-1, and FN. Notably, oral administration of PEC at a dose of 25 mg/kg/d for 7 days or 14 days effectively ameliorated kidney injury and tubulointerstitial fibrosis after unilateral ureteral obstruction (UUO) surgery in mice. Mechanically, PEC treatment inhibited the phosphorylated activation of SMAD3 and STAT3, which further reduced the protein expression of TGFβ, α-SMA, COL-1, and FN in the obstructed kidneys of UUO mice. In summary, our results suggested that pectolinarigenin alleviated tubulointerstitial fibrosis by inhibiting the activation of SMAD3 and STAT3 signaling.

Pectolinarigenin promotes functional recovery and inhibits apoptosis in rats following spinal cord injuries.

Spinal cord injury (SCI) is a devastating neurological injury that frequently leads to neurological defects and disabilities. The only effective pharmacotherapy currently available is methylprednisolone (MP), which is controversial due to its high incidence of complications, adverse events and ultimately limited efficacy in SCI. Therefore, the development of alternative therapeutic agents for the treatment of SCI is of great clinical significance. In the present study, an acute SCI rat model was induced and, following a modified Allen method, the function of pectolinarigenin (PG) in SCI was investigated. A total of 36 rats were randomly divided into 6 groups (n=6 in each group); a sham surgery group and an SCI + saline group were used as negative controls and an SCI + MP (30 mg/kg) group was used as a positive control. The remaining animals were subdivided into three groups: SCI + PG (10 mg/kg); SCI + PG (30 mg/kg); and SCI + PG (50 mg/kg). Basso-Beattie-Bresnahan locomotor rating scoring was performed to assess functional recovery. Nissl staining and TUNEL staining were used to evaluated neuronal lesion volume and apoptosis, respectively. The results demonstrated that PG significantly improved functional recovery and reduced tissue loss, and neuronal apoptosis. Furthermore, a western blotting assay was conducted to measure the expression of genes associated with apoptosis. The data suggested that PG downregulated the activated caspase-3, caspase-9 and poly-ADP-ribose polymerase expression and reduced the Bax: Bcl2 ratio. The findings of the present study suggested that PG may exert a protective effect against SCI in rats, potentially by inhibiting neuronal apoptosis and PG may therefore serve as a novel therapeutic agent against SCI.

Pectolinarigenin prevents bone loss in ovariectomized mice and inhibits RANKL-induced osteoclastogenesis via blocking activation of MAPK and NFATc1 signaling.

Osteoporosis (OP) is a metabolic disease caused by multiple factors, which is characterized by a reduction of bone mass per unit volume and destruction of bone microstructure. Aberrant osteoclast function is the main cause of OP, therefore, regulating the differentiation and function of osteoclast is one of the treatment strategies for OP. Pectolinarigenin (PEC) is a medicinal implant isolated from Fragrant Eupatorium. Our experimental data showed that PEC was able to inhibit receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in vitro, by tartrate-resistant acid phosphatase (TRAcP) staining, Fibrous actinring formation, and hydroxyapatite resorption assays. In terms of mechanism, PEC inhibited the expression of the osteoclastogenesis-related gene, including cathepsin K (Ctsk), matrix metalloproteinase 9 (Mmp9), and TRAcP (Acp5). Western blot analysis demonstrated that PEC could significantly block the activation of RANKL-induced mitogen-activated protein kinase signaling cascades and was able to suppress the protein expression of nuclear factor of activated T-cells and c-Fos. Meanwhile, the intracellular reactive oxygen species levels were also reduced by PEC in a concentration-dependent manner. Further, PEC could prevent the ovariectomy-induced bone loss in vivo. Summarizing all, our data suggested that PEC inhibits osteoclast formation and function and RANKL signaling pathways, and thus could potentially be used in the treatment the osteoclast-related bone loss diseases.

Comparative Proteomic Profiling of Tumor-Associated Proteins in Human Gastric Cancer Cells Treated with Pectolinarigenin.

Pectolinarigenin (PEC), a natural flavonoid that is present in citrus fruits, has been reported to exhibit antitumor effects in several cancers. Though the mechanism of PEC-induced cytotoxicity effects has been documented, the proteomic changes that are associated with the cellular response to this flavonoid are poorly understood in gastric cancer cells. In this study, a comparative proteomic analysis was performed to identify proteins associated with PEC-induced cell death in two human gastric cancer cell lines: AGS and MKN-28. Two-dimensional gel electrophoresis (2-DE) revealed a total of 29 and 56 protein spots with significant alteration were screened in AGS and MKN-28 cells respectively. In total, 13 (AGS) and 39 (MKN28) proteins were successfully identified by mass spectrometry from the differential spots and they are known to be involved in signal transduction, apoptosis, transcription and translation, cell structural organization, and metabolism, as is consistent with multiple effects of PEC on tumor cells. Notably, novel target proteins like Probable ATP-dependent RNA helicase DDX4 (DDX4) and E3 ubiquitin-protein ligase LRSAM1 (LRSAM1) along with the commonly differential expressed proteins on both the cell lines that are treated with PEC were confirmed by immunoblotting. The DDX4 accelerates cell cycle progression by abrogating the G2 checkpoint when overexpressed in cancer cells, while the aberrant expression of LRSAM1 may be involved in the cancer pathology. Thus, proteomic analysis provides vital information about target proteins that are important for PEC-induced cell death in gastric cancer cells.

Pectolinarigenin Induced Cell Cycle Arrest, Autophagy, and Apoptosis in Gastric Cancer Cell via PI3K/AKT/mTOR Signaling Pathway.

Pectolinarigenin (PEC), a natural flavonoid present in Cirsium chanroenicum and in some species of Citrus fruits, has various pharmacological benefits such as anti-inflammatory and anti-cancer activities. In the present study, we investigated the anti-cancer mechanism of PEC induced cell death caused by autophagy and apoptosis in AGS and MKN28 human gastric cancer cells. The PEC treatment significantly inhibited the AGS and MKN28 cell growth in a dose-dependent manner. Further, PEC significantly elevated sub-G1 phase in AGS cells and G2/M phase cell cycle arrest in both AGS and MKN28 cells. Apoptosis was confirmed by Annexin V and Hoechst 33342 fluorescent staining. Moreover, Immunoblotting results revealed that PEC treatment down-regulated the inhibitor of apoptosis protein (IAP) family protein XIAP that leads to the activation of caspase-3 thereby cleavage of PARP (poly-ADP-ribose polymerase) in both AGS and MKN28 cells in a dose-dependent manner. The autophagy-inducing effect was indicated by the increased formation of acidic vesicular organelles (AVOs) and increased protein levels of LC3-II conversion in both AGS and MKN28 cells. PEC shows the down regulation of PI3K/AKT/mTOR pathway which is a major regulator of autophagic and apoptotic cell death in cancer cells that leads to the down-regulation of p-4EBP1, p-p70S6K, and p-eIF4E in PEC treated cells when compared with the untreated cells. In conclusion, PEC treatment might have anti-cancer effect by down-regulation of PI3K/AKT/mTOR pathway leading to G2/M phase cell cycle arrest, autophagic and apoptotic cell death in human gastric cancer cells. Further studies of PEC treatment can support to develop as a potential alternative therapeutic agent for human gastric carcinoma.

Flavonoids from Brickellia chlorolepis and B. dentata

Eleven flavonoids including three new glycosides were isolated from Brickellia chlorolepis and one new and nine known flavonoids were obtained from B. dentata. The new glycosides from B. chlorolepis are 6-methoxykaempferol 3-rhamnoglucoside, spinacetin 3-rhamnogalactoside and veronicafolin 3-rhamnoglucoside. The known compounds identified from B. chlorolepis are patuletin, casticin, artemetin, eupatolitin 3-galactoside, quercetin 3-rhamnogalactoside, rutin, isorhamnetin 3-galactoside and eupatin 3-SO 3Ca 1 2 . B. dentata contains the new glycoside eupalitin 3-galactoside and nine known compounds: pectolinarigenin, salvigenin, eupafolin, cirsiliol, eupatorin, eupatolitin, eupatolitin 3-glucoside, eupatolitin 3-galactoside and eupatin.