Poncirus trifoliata fruit induces apoptosis in human promyelocytic leukemia cells

Poncirus trifoliata Aqueous Extract Protects Cardiomyocytes against Doxorubicin-Induced Toxicity through Upregulation of NAD(P)H Dehydrogenase Quinone Acceptor Oxidoreductase 1

Doxorubicin (DOX), an anthracycline-based chemotherapeutic agent, is widely used to treat various types of cancer; however, prolonged treatment induces cardiomyotoxicity. Although studies have been performed to overcome DOX-induced cardiotoxicity (DICT), no effective method is currently available. This study investigated the effects and potential mechanisms of Poncirus trifoliata aqueous extract (PTA) in DICT. Changes in cell survival were assessed in H9c2 rat cardiomyocytes and MDA-MB-231 human breast cancer cells. The C57BL/6 mice were treated with DOX to induce DICT in vivo, and alterations in electrophysiological characteristics, serum biomarkers, and histological features were examined. The PTA treatment inhibited DOX-induced decrease in H9c2 cell viability but did not affect the MDA-MB-231 cell viability. Additionally, the PTA restored the abnormal heart rate, R-R interval, QT interval, and ST segment and inhibited the decrease in serum cardiac and hepatic toxicity indicators in the DICT model. Moreover, the PTA administration protected against myocardial fibrosis and apoptosis in the heart tissue of mice with DICT. PTA treatment restored DOX-induced decrease in the expression of NAD(P)H dehydrogenase quinone acceptor oxidoreductase 1 in a PTA concentration-dependent manner. In conclusion, the PTA inhibitory effect on DICT is attributable to its antioxidant properties, suggesting the potential of PTA as a phytotherapeutic agent for DICT.

Poncirus trifoliata (L.) Raf. Seed Extract Induces Cell Cycle Arrest and Apoptosis in the Androgen Receptor Positive LNCaP Prostate Cancer Cells

Prostate cancer (PCa) is the second most common male cancer. Its incidence derives from the interaction between modifiable and non-modifiable factors. The progression of prostate cancer into a more aggressive phenotype is associated with chronic inflammation and increased ROS production. For their biological properties, some phytochemicals from fruits and vegetable emerge as a promise strategy for cancer progression delay. These bioactive compounds are found in the highest amounts in peels and seeds. Poncirus trifoliata (L.) Raf. (PT) has been widely used in traditional medicine and retains anti-inflammatory, anti-bacterial, and anticancer effects. The seeds of P. trifoliata were exhaustively extracted by maceration with methanol as the solvent. The cell proliferation rate was performed by MTT and flow cytometry, while the apoptosis signals were analyzed by Western blotting and TUNEL assay. P. trifoliata seed extract reduced LNCaP and PC3 cell viability and induced cell cycle arrest at the G0/G1phase and apoptosis. In addition, a reduction in the AKT/mTOR pathway has been observed together with the up-regulation of stress-activated MAPK (p38 and c-Jun N-terminal kinase). Based on the study, the anti-growth effects of PT seed extract on prostate tumor cells give indications on the potential of the phytochemical drug for the treatment of this type of cancer. However, future in-depth studies are necessary to identify which components are mainly responsible for the anti-neoplastic response.

Ponciri Fructus Immatarus Sensitizes the Apoptotic Effect of Hyperthermia Treatment in AGS Gastric Cancer Cells through ROS-Dependent HSP Suppression

Gastric cancer has been associated with a high incidence and mortality, accompanied by a poor prognosis. Given the limited therapeutic options to treat gastric cancer, alternative treatments need to be urgently developed. Hyperthermia therapy is a potentially effective and safe treatment option for cancer; however, certain limitations need to be addressed. We applied 43 °C hyperthermia to AGS gastric cancer cells combined with Ponciri Fructus Immaturus (PF) to establish their synergistic effects. Co-treatment with PF and hyperthermia synergistically suppressed AGS cell proliferation by inducing extrinsic and intrinsic apoptotic pathways. Additionally, PF and hyperthermia suppressed factors related to metastasis. Cell cycle arrest was determined by flow cytometry, revealing that co-treatment induced arrest at the G2/M phase. As reactive oxygen species (ROS) are critical in hyperthermia therapy, we next examined changes in ROS generation. Co-treatment with PF and hyperthermia increased ROS levels, and apoptotic induction mediated by this combination was partially dependent on ROS generation. Furthermore, heat shock factor 1 and heat shock proteins (HSPs) were notably suppressed following co-treatment with PF and hyperthermia. The HSP-regulating effect was also dependent on ROS generation. Overall, these findings suggest that co-treatment with PF and hyperthermia could afford a promising anticancer therapy for gastric cancer.

Bioactive Chemical Constituents and Pharmacological Activities of Ponciri Fructus

Ponciri Fructus is a crude drug obtained from the dried immature fruits of Poncirus trifoliata (L). Raf. (Syn. Citrus trifoliata L.). This study aims to compile and analyze the ethnomedicinal uses, bioactive constituents, and pharmacological activities of Ponciri Fructus. Various online bibliographic databases namely, SciFinder, PubMed, Google Scholar, and Web of Science were used for collecting information on traditional uses, biological activities, and bioactive constituents. Concerning ethnomedicinal uses, Ponciri Fructus is extensively used in traditional Korean, Chinese, and Kampo medicines to mitigate allergic reactions, inflammation, edema, digestive complications, respiratory problems, spleen-related problems, liver complications, neuronal pain, hyperlipidemia, rheumatoid arthritis, cardiovascular problems, hernia, sinusitis, and insomnia. Several studies have shown that Ponciri Fructus is a major source of diverse classes of bioactive compounds namely flavonoids, terpenoids, coumarins, phytosterols, and alkaloids. Several in vivo and in vitro pharmacological activity evaluations such as antidiabetic, anti-obesity, anti-inflammatory, antiallergic, antimelanogenic, gastroprotective, anticancer, and neuroprotective effects have been conducted from Ponciri Fructus. However, scientific investigations focusing on bioassay-guided isolation and identification of specific bioactive constituents are limited. Therefore, an in-depth scientific investigation of Ponciri Fructus focusing on bioassay-guided isolation, mechanism based pharmacological studies, pharmacokinetic studies, and evaluation of possible toxicities is necessary in the future.

A chromosome-scale reference genome of trifoliate orange (Poncirus trifoliata) provides insights into disease resistance, cold tolerance and genome evolution in Citrus

Trifoliate orange (Poncirus trifoliata), a deciduous close relative of evergreen Citrus, has important traits for citrus production, including tolerance/resistance to citrus greening disease (Huanglongbing, HLB) and other major diseases, and cold tolerance. It has been one of the most important rootstocks, and one of the most valuable sources of resistance and tolerance genes for citrus. Here we present a high-quality, chromosome-scale genome assembly of P. trifoliata. The 264.9-Mb assembly contains nine chromosomal pseudomolecules with 25 538 protein-coding genes, covering 97.2% of the estimated gene space. Comparative analyses of P. trifoliata and nine Citrus genomes revealed 605 species-specific genes and six rapidly evolving gene families in the P. trifoliata genome. Poncirus trifoliata has evolved specific adaptation in the C-repeat/DREB binding factor (CBF)-dependent and CBF-independent cold signaling pathways to tolerate cold. We identified candidate genes within quantitative trait loci for HLB tolerance, and at the loci for resistance to citrus tristeza virus and citrus nematode. Genetic diversity analysis of Poncirus accessions and Poncirus/Citrus hybrids shows a narrow genetic base in the US germplasm collection, and points to the importance of collecting and preserving more natural genetic variation. Two phenotypically divergent Poncirus accessions are found to be clonally related, supporting a previous conjecture that dwarf Flying Dragon originated as a mutant of a non-dwarfing type. The high-quality genome reveals features and evolutionary insights of Poncirus, and it will serve as a valuable resource for genetic, genomic and molecular research and manipulation in citrus.

Anticancer effects of Poncirus fructus on hepatocellular carcinoma through regulation of apoptosis, migration, and invasion

Poncirus fructus (PF) is a phytochemical compound extracted from the dry, immature fruits of Poncirus trifoliate. PF is traditionally used to treat gastrointestinal disorders, allergies, and inflammatory disease. In East Asia, PF is also known for its anticancer properties. There are numerous reports on the anticancer and anti-inflammatory effects of PF in a wide range of cancers and gastrointestinal diseases, respectively. However, the role of PF in inducing apoptosis and suppressing the invasiveness of hepatocellular carcinoma (HCC) remains unclear. This study investigated the ability of PF to induce apoptosis and inhibit the invasiveness and migratory ability of HCC cell lines (Hep3B and Huh7). Wound healing, Transwell migration and invasion, and colony-formation assays, as well as flow cytometry, were used to analyze cell proliferation, migration, invasion, and apoptosis. Epithelial-mesenchymal transition (EMT)-related and apoptotic proteins were assessed by western blotting. The mitochondrial membrane potential of the Hep3B and Huh7 cells was observed with tetramethylrhodamine ethyl ester. The reactive oxygen species (ROS) level was determined by dihydroethidium (DHE) staining. PF treatment significantly decreased the proliferation of Hep3B and Huh7 cells in a dose-dependent manner, reduced the mitochondrial membrane potential, increased ROS levels, decreased the protein levels of Bcl-2, and increased the protein levels of Bax and cleaved caspase-3 and 9, suggesting that PF mediated HCC apoptosis via a mitochondrial pathway. Our findings showed that PF prevented HCC cell migration and invasion by inhibiting the EMT process and downregulating MMP-2 and MMP-9 activities. The results suggest the potential anticancer effects of PF by inhibiting proliferation, inducing apoptosis, and reducing the invasion and migration of HCC cells.

Phytochemicals and antioxidant capacity of some tropical edible plants

OBJECTIVE

To find biological functions such as antibacterial and antioxidant activities in several tropical plants and to investigate the possibility of antibiotic substitute agents to prevent and treat diseases caused by pathogenic bacteria.

METHODS

Plants such as Poncirus trifoliata fruit (Makrut), Zingiber officinale Rosc (Khing), Areca catechu L. (Mak), Solanum melongena L. I (Makkhuayao), and Solanum melongena L. II (Makhurapro) were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. The free radical scavenging activities were measured using 2-diphenyl-2-picryl hydrazyl photometric assay. Antibacterial activities with a minimum inhibitory concentration (MIC) were observed by agar diffusion assay against pathogenic strains of Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, Clostridium perfringens, and Pantoea agglomerans.

RESULTS

Poncirus trifoliata fruit methanol extract showed antibacterial activities against gram-negative and gram-positive pathogens. Additionally, this showed the strongest antibacterial activity against Burkholderia sp. and Haemopilus somnus with MIC 131 μg/mL, respectively. Areca catechu L. water extract showed antibacterial activities against Burkholderia sp., Haemopilus somnus, and Haemopilus parasuis. The MIC value for Haemopilus parasuis was 105 μg/mL in this. Antioxidant activity of Zingiber officinale Rosc n-hexane extract showed 2.23 mg/mL effective concentration 50% (EC50) value was the highest activity among tropical plants extracts. Total polyphenol content in Zingiber officinale Rosc methanol extract was 48.4 μg/mL and flavonoid content was 22.1 μg/mL showed the highest values among tested plants extracts.

CONCLUSION

Taken together, these results suggest that tropical plants used in this study may have a potential benefit as an alternative antibiotics agent through their antibacterial and antioxidant activities.

Phytotherapeutic effects of the fruits of Poncirus trifoliata (L.) Raf. on cancer, inflammation, and digestive dysfunction

Poncirus trifoliata (L.) Raf. belongs to the family Rutaceae in the genus Poncirus. Its fruits are widely used to alleviate symptoms of various disorders. The mature fruit (MF) possesses anticancer and antiinflammatory activities. Extracts of the dried, immature fruit, Poncirus fructus (PF) are widely used as a traditional medicine for ameliorating symptoms of digestive dysfunction in East Asia. Molecular and cellular mechanisms underlying the effects of MF and PF extracts on cancer, inflammation, and gastrointestinal disorders have been extensively studied in the past decade. This review summarizes recent findings on the anticancer and antiinflammatory effects of MF and the prokinetic effects of PF. Although the therapeutic effects of MF and PF have been clearly elucidated, in-depth further clinical studies are still required to completely verify the clinical efficacy and safety of the fruits of P. trifoliata (L.) Raf.

Prokinetic effects of LD02GIFRO on functional gastrointestinal disorder in rats

LD02GIFRO is a novel prokinetic agent formulated with Poncirus fructus and Zanthoxylum sp. fruits. The aim of the present study was to evaluate the effect of LD02GIFRO on delayed gastrointestinal transit (GIT) and colorectal hypersensitivity. To investigate the effect of LD02GIFRO, a rat model of delayed GIT was induced via three mechanisms; postoperative ileus (POI), morphine, and POI plus morphine. Visceromotor responses (VMR) to colorectal distension (CRD) were also evaluated. POI was induced by laparotomy surgery and manipulation of the small intestine under anesthesia, and GIT was calculated by measuring the length that Evans Blue travelled through the gastrointestinal tract in a given time. Oral administration of 260 mg/kg LD02GIFRO caused Evans Blue to migrate significantly further in the delayed GIT models induced by POI, morphine and POI plus morphine compared with the control (P<0.05). This effect was inhibited by atropine, a muscarinic receptor antagonist, and completely abolished by GR125487, a 5-HT₄-receptor antagonist. Furthermore, intraperitoneal administration of 600 and 900 mg/kg LD02GIFRO significantly reduced VMR to CRD in acute and chronic colorectal hypersensitive rat models, induced by acetic acid and trinitrobenzenesulfonic acid, to almost normal levels (P<0.01). In the present study, LD02GIFRO successfully ameliorated delayed GIT models and colorectal hypersensitivity models, suggesting that LD02GIFRO may be an effective therapeutic treatment for patients with functional gastrointestinal disorders and abnormalities in GIT.

Effects and Safety of Aqueous Extract of Poncirus fructus in Spinal Cord Injury with Neurogenic Bowel

Objective. To investigate the effects and safety of the aqueous extract of the dried, immature fruit of Poncirus trifoliata (L.) Raf., known as Poncirus fructus (PF), in spinal cord injury (SCI) patients with neurogenic bowel. Methods. Thirty-one SCI patients with neurogenic bowel were recruited. Patients were evaluated based on clinical information, constipation score, Bristol Stool Form Scale, stool retention score using plain abdominal radiograph, and colon transit time. PF was administered in dosages of 800 mg each prior to breakfast and lunch for 14 days. Results. The morphological feature of the stool before and after administration indicated a statistically significant difference from 3.52 ± 1.33 to 4.32 ± 1.44 points (p < 0.05). Stool retention score before and after administration of PF was represented with low significance (7.25 ± 1.60 to 6.46 ± 1.53 points) in the whole colon (p < 0.05), and the colon transit time was significantly shortened (57.41 ± 20.7 to 41.2 ± 25.5 hours) in terms of the whole transit time (p < 0.05). Side effects were observed in 7 people (28.0%) consisting of 2 people with soft stools and 5 people with diarrhea. Conclusion. For SCI patients, PF administration significantly improved defecation patterns, defecation retention, and colon transit time. PF could be an effective aid to improve colonic motility and constipation.

Anti-Obesity and Hypoglycemic Effects of Poncirus trifoliata L. Extracts in High-Fat Diet C57BL/6 Mice

The present study investigated the possible anti-obesity and hypoglycemic effects of Poncirus trifoliata L. extracts. Mature fruit were divided into flavedo (PF) and juice sacs (PJ), and extracts from them were tested on C57BL/6 mice fed a high-fat diet (HFD) for thirteen weeks. Both fruit extracts (40 mg/kg body weight, respectively) showed anti-obesity and hypoglycemic effects. Consumption of PF and PJ extracts reduced body weight by 9.21% and 20.27%, respectively. Liver and adipose weights, fasting glucose, serum triglyceride (TG), and low density lipoprotein cholesterol (LDL-c) levels decreased significantly, while serum high density lipoprotein cholesterol (HDL-c) and oral glucose tolerance levels increased significantly in response to two fruit extracts. These effects were due in part to the modulation of serum insulin, leptin, and adiponectin. Furthermore, transcript levels of fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1) were reduced while those of carnitine palmitoyltransferase 1α (CPT1α) and insulin receptor substrate 2 (IRS2) were increased in the liver of C57BL/6 mice, which might be an important mechanism affecting lipid and glucose metabolism. Taken together, P. trifoliata fruit can be potentially used to prevent or treat obesity and associated metabolic disorders.

Poncirus trifoliata Rafin. induces the apoptosis of triple-negative breast cancer cells via activation of the c-Jun NH(2)-terminal kinase and extracellular signal-regulated kinase pathways

Background:

Poncirus trifoliata Rafin. is a traditional medicine with known anti-inflammatory and anti-cancer properties. Traditionally, it is used to control chronic inflammation, allergy and gastrointestinal diseases such as digestive ulcers gastritis in China, Japan, and Korea.

Objectives:

To evaluate the apoptosis-inducing activity of a P. trifoliata methanol extract (MEPT) and elucidate the molecular mechanisms.

Materials and Methods:

The anti-cancer effect of MEPT and its underlying mechanisms were investigated in breast cancer cells using 3,4,5-dimethyl N-methylthiazol-2-yl-2, 5-d-phenyl tetrazolium bromide assay, cell cycle analysis, and western blotting.

Results:

MEPT suppressed the proliferation of MDA-MB-231 cells with inhibition dose 50% value of 119.44 μg/mL at 24 h, which have features typical of triple-negative breast cancer cells. MEPT also altered the characteristic features of the MDA-MB-231 cells and increased the proportion of cells undergoing sub-G1 arrest. In addition, MEPT increased levels of caspase 8 and 3 in MDA-MB-231 cells, whereas caspase 9 was not detected. In addition, MEPT-induced tumor necrosis factor receptor (TNFR) and TNFR type 1-associated death domain (TRADD) protein and the activations of c-Jun NH(2)-terminal kinase (JNK) and extracellular signal-regulated kinases (ERK).

Conclusion:

Our results indicate that MEPT has chemotherapeutic potential in triple-negative breast cancer and that at the molecular level its effects are derived from the activations of TNFR and of the mitogen-activated protein kinase pathway.

Autophagic Cell Death by Poncirus trifoliata Rafin., a Traditional Oriental Medicine, in Human Oral Cancer HSC-4 Cells

Poncirus trifoliata Rafin. has long been used as anti-inflammatory and antiallergic agent to treat gastrointestinal disorders and pulmonary diseases such as indigestion, constipation, chest fullness, chest pain, bronchitis, and sputum in Korea. P. trifoliata extract has recently been reported to possess anticancer properties; however, its mechanisms of action remain unclear. In this study, its antiproliferative effects and possible mechanisms were investigated in HSC-4 cells. The methanol extract of P. trifoliata (MEPT) significantly decreased the proliferation of HSC-4 cells (inhibitory concentration (IC)₅₀ = 142.7 μg/mL) in a dose-dependent manner. While there were no significant changes observed upon cell cycle analysis and ANNEXIN V and 7-AAD double staining in the MEPT-treated groups, the intensity of acidic vesicular organelle (AVO) staining and microtubule-associated protein 1 light chain (LC) 3-II protein expression increased in response to MEPT treatment. Furthermore, 3-methyladenine (3-MA, autophagy inhibitor) effectively blocked the MEPT-induced cytotoxicity of HSC-4 cells and triggered the activation of p38 and extracellular signal-regulated kinases (ERK) proteins. Taken together, our results indicate that MEPT is a potent autophagy agonist in oral cancer cells with antitumor therapeutic potential that acts through the mitogen-activated protein kinase (MAPK) pathway.

Effects of San-Huang-Xie-Xin-tang, a traditional Chinese prescription for clearing away heat and toxin, on the pacemaker activities of interstitial cells of Cajal from the murine small intestine

ETHNOPHARMACOLOGICAL RELEVANCE

San-Huang-Xie-Xin-Tang (SHXXT) is a traditional Chinese medicinal formula composed of Coptidis rhizoma (Coptis chinesis Franch), Scutellariae radix (Scutellaria baicalensis Georgi), and Rhei rhizoma (Rheum officinale Baill) and is widely used in Eastern Asia, especially to ameliorate the symptoms of gastrointestinal (GI) disorders related to gastritis, gastric bleeding, peptic ulcers, and abnormal GI motility

AIM OF THE STUDY

Interstitial cells of Cajal (ICCs) are pacemaker cells in the GI tract that generate rhythmic oscillations in membrane potentials known as slow waves. Because GI disorders, especially abnormal GI motility, are major lifelong problems, the authors investigated the effects of SHXXT on mouse small intestine ICCs, and sought to identify the receptors and the action mechanisms involved.

MATERIALS AND METHODS

Enzymatic digestions were used to dissociate ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record potentials generated by cultured ICCs.

RESULTS

SHXXT produced membrane depolarization in current-clamp mode, and Y25130 (a 5-HT3 receptor antagonist) and RS39604 (a 5-HT4 receptor antagonist) blocked SHXXT-induced membrane depolarizations, whereas SB269970 (a 5-HT7 receptor antagonist) did not. However, during external Ca2+ free conditions or in the presence of thapsigargin, SHXXT did not exhibit membrane depolarization. Furthermore, the application of flufenamic acid (a nonselective cation channel (NSCC) blocker) or DIDS (a chloride channel blocker) abolished pacemaker potential generation and blocked SHXXT-induced membrane depolarizations. In addition, SHXXT-induced membrane depolarizations, which are dependent on G-protein, in ICCs were blocked by PD 98059 (a p42/44 mitogen-activated protein kinase (MAPK) inhibitor), SB203580 (a p38 MAPK inhibitor), and by a c-jun NH2-terminal kinase (JNK) II inhibitor. Regarding the components of SHXXT, Coptidis rhizome and Rhei rhizoma modulated ICC pacemaking activity, whereas Scutellariae radix did not.

CONCLUSION

SHXXT modulates pacemaker potentials via 5-HT3 and 5-HT4 receptor-mediated pathways, external Ca2+ influx, and Ca2+ release from internal stores. Furthermore, NSCCs and Cl- channels play important roles in the regulation of pacemaking activity in a MAPK dependent manner in ICCs. The regulation of pacemaking activity by SHXXT may be due to the activity of Coptidis rhizome and Rhei rhizome. The study shows SHXXT can modulate the pacemaking activity of ICCs in the GI tract, and thus, suggests SHXXT has potential pharmacological relevance for the treatment of GI motility disorders.

Involvement of MAPKs and PLC pathways in modulation of pacemaking activity by So-Cheong-Ryong-Tang in interstitial cells of Cajal from murine small intestine

Purpose. Interstitial cells of Cajal (ICCs) are the pacemaker cells that generate slow waves in the gastrointestinal (GI) tract. We have aimed to investigate the effects of Socheongryong-Tang (SCRT) in ICCs from mouse's small intestine. Methods. The whole-cell patch-clamp configuration was used to record membrane potentials from cultured ICCs. Intracellular Ca²⁺ ([Ca²⁺]_i) increase was studied in cultured ICCs using fura-2 AM. Results. ICCs generated pacemaker potentials in mouse's small intestine. SCRT produced membrane depolarization in current clamp mode. Y25130 (5-HT₃ receptor antagonist) and RS39604 (5-HT₄ receptor antagonist) blocked SCRT-induced membrane depolarizations, whereas SB269970 (5-HT₇ receptor antagonist) did not. When GDP-β-S (1 mM) was in the pipette solution, SCRT did not induce the membrane depolarizations. [Ca²⁺]_i analysis showed that SCRT increased [Ca²⁺]_i. In the presence of PD98059 (p42/44 MAPK inhibitor), SCRT did not produce membrane depolarizations. In addition, SB203580 (p38 MAPK inhibitor) and JNK inhibitors blocked the depolarizations by SCRT in pacemaker potentials. Furthermore, the membrane depolarizations by SCRT were not inhibited by U-73122, an active phospholipase C (PLC) inhibitor, but by U-73343, an inactive PLC inhibitor. Conclusion. These results suggest that SCRT might affect GI motility by the modulation of pacemaker activity through MAPKs and PLC pathways in the ICCs.

Poncirus trifoliate fruit modulates pacemaker activity in interstitial cells of Cajal from the murine small intestine

ETHNOPHARMACOLOGICAL RELEVANCE

Poncirus fructus (PF) has been widely used as a traditional medicine in Eastern Asia, especially to ameliorate the symptoms of gastrointestinal (GI) disorders related to abnormal GI motility.

AIM OF THE STUDY

Poncirus fructus (PF), also known as Poncirus trifoliata (L.) Raf. (Rutaceae), is widely used as a traditional medicine in Eastern Asia mainly to ameliorate the symptoms of gastrointestinal (GI) disorders related to abnormal GI motility. In a previous study, a methanol extract of PF was found to have particularly potent gastroprokinetic effects. Interstitial cells of Cajal (ICCs) are pacemaker cells in the gastrointestinal tract, but the action mechanisms of PF extract in mouse small intestinal ICCs have not been investigated. Therefore, in the present study, we investigated the effects of a methanol extract of PF (MPF) in mouse small intestinal ICCs. In addition, we sought to identify the receptors involved.

MATERIALS AND METHODS

Enzymatic digestions were used to dissociate ICCs from small intestines. The whole-cell patch-clamp configuration was used to record potentials (current clamp) from cultured ICCs. In addition, we analyzed intracellular Ca(2+) concentrations ([Ca(2+)]i).

RESULTS

MPF decreased the amplitudes of pacemaker potentials in ICCs, and depolarized resting membrane potentials in a concentration dependent manner. Y25130 (a 5-HT3 receptor antagonist) and RS39604 (a 5-HT4 receptor antagonist) blocked MPF-induced membrane depolarizations, whereas SB269970 (a 5-HT7 receptor antagonist) did not. Pretreatment with Na(+) or Ca(2+)-free solution or thapsigargin (a Ca(2+)-ATPase inhibitor in endoplasmic reticulum) abolished the generation of pacemaker potentials and suppressed MPF-induced activity. [Ca(2+)]i analysis showed that MPF increased [Ca(2+)]i. Furthermore, treatments with PD 98059, SB203580, or JNK II inhibitor blocked MPF-induced membrane depolarizations in ICCs.

CONCLUSION

These results suggest that MPF modulates pacemaker potentials through 5-HT3 and 5-HT4 receptor-mediated pathways via external Na(+) and Ca(2+) influx, and via Ca(2+) release from internal stores in a mitogen-activated protein kinase dependent manner. The study shows MPF is a good candidate for the development of a gastroprokinetic agent. In view of the effects of MPF on ICCs, further research is required, particularly to identify the active compound(s) involved and to determine their action mechanisms.

Involvement of transient receptor potential melastatin type 7 channels on Poncirus fructus-induced depolarizations of pacemaking activity in interstitial cells of Cajal from murine small intestine

Background

Extracts of Poncirus trifoliata (L.) Raf. (Rutaceae; PT) are widely used as a traditional medicine in Eastern Asia, especially for the treatment of gastrointestinal (GI) disorders related to GI motility. Interstitial cells of Cajal (ICCs) are pacemakers in the GI tract, and transient receptor potential melastatin type 7 (TRPM7) channels and Ca²⁺ activated Cl^– channels are candidate pacemaker channels.

Methods

In the present study, the effects of a methanolic extract of the dried roots of PT on ICC pacemaking activity were examined using the whole-cell patch-clamp technique.

Results

The methanolic extract of PT (PTE) was found to decrease the amplitudes of pacemaker potentials in ICC clusters and to depolarize the resting membrane potentials in a concentration-dependent manner. Intracellular GDP-β-S suppressed PTE-induced depolarizations, and pretreatment with a U-73122 (a phospholipase C inhibitor) or with 2-APB (an 1,4,5-inositol triphosphate receptor inhibitor) abolished this generation of pacemaker potentials and suppressed PTE-induced effects. The applications of flufenamic acid, niflumic acid, waixenicin A, or 5-lipoxygenase inhibitors (NDGA or AA861) abolished this generation of pacemaker potentials and inhibited PTE-induced membrane depolarization. Furthermore, PTE inhibited TRPM7 channels but did not affect Ca²⁺-activated Cl^– channels (both channels play important roles in the modulation of the pacemaking activity related to GI motility).

Conclusion

These results suggest that the PTE-induced depolarization of pacemaking activity occurs in a G-protein-, phospholipase C-, and 1,4,5-inositol triphosphate-dependent manner via TRPM7 channels in cultured ICCs from murine small intestine, which indicates that ICCs are PTE targets and that their interactions affect intestinal motility.

In vitro and in vivo inhibition of glucocorticoid-induced osteoporosis by the hexane extract of Poncirus trifoliata

This study was performed to discover a novel herbal therapeutic for effective glucocorticoid-induced osteoporosis (GIO) treatment and further to clarify its molecular mechanism of action. Ethanol or methanol extracts of 68 edible Korean native plants were screened to find effective natural plant sources for the treatment of GIO, and Poncirus trifoliata (L.) (Rutaceae, PT) was selected as a final candidate because of its high inhibitory activity plus its novelty. The hexane extract of PT (PT-H) inhibited apoptotic cell death in dexamethasone-induced osteoblastic cell lines, C3H10T1/2 and MC3T3-E1. In vivo mouse results indicated that PT-H not only had an inhibitory effect on the bone loss caused by glucocorticoid, but also promoted bone formation. The molecular mechanisms behind the effect of PT-H on GIO were further clarified by screening of differentially expressed genes (DEGs) between dexamethasone (Dex)-induced osteoblastic cells with or without PT-H treatment. Finally, it was found that the expression level of AnxA6 in Dex-induced osteoblastic cells and prednisolone (PD)-treated GIO-model mice was significantly decreased by PT-H treatment. These findings suggest that PT-H has a strong in vitro and in vivo inhibitory effect on GIO, and decreased expression of AnxA6 may play a key role in this inhibition.

Transcriptional response of susceptible and tolerant citrus to infection with Candidatus Liberibacter asiaticus

Candidatus Liberibacter asiaticus (Las), a non-culturable phloem-limited bacterium, is the suspected causal agent of huanglongbing (HLB) in Florida. HLB is one of the most devastating diseases of citrus and no resistant cultivars have been identified to date, though tolerance has been observed in the genus Poncirus and some of its hybrids. This study compares transcriptional changes in tolerant US-897 (Citrus reticulata Blanco×Poncirus trifoliata L. Raf.) and susceptible 'Cleopatra' mandarin (C. reticulata) seedlings in response to infection with Las using the Affymetrix GeneChip citrus array, with the main objective of identifying genes associated with tolerance to HLB. Microarray analysis identified 326 genes which were significantly upregulated by at least 4-fold in the susceptible genotype, compared with only 17 genes in US-897. Exclusively upregulated in US-897 was a gene for a 2-oxoglutarate (2OG) and Fe(II)-dependant oxygenase, an important enzyme involved in the biosynthesis of plant secondary metabolites. More than eight hundred genes were expressed at much higher levels in US-897 independent of infection with Las. Among these, genes for a constitutive disease resistance protein (CDR1) were notable. The possible involvement of these and other detected genes in tolerance to HLB and their possible use for biotechnology are discussed.

An aqueous extract of Poncirus fructus activates the prokinetic activity of 5-HT receptor subtype 4 without hERG interaction

AIM OF THE STUDY

Poncirus fructus (PF)--also known as the dried, immature fruit of Poncirus trifoliata (L.) Raf. (Rutaceae)--is a natural substance that has long been used for various gastrointestinal disorders in eastern Asia. An aqueous extract of PF (PF-W) has particularly potent gastroprokinetic effects, but its molecular mechanism was not well understood. Identification of the underlying prokinetic mechanism of PF-W was pursued in the present study.

MATERIALS AND METHODS

Changes in in vitro cAMP levels and in vivo intestinal transit rate (ITR) caused by PF-W were measured after pretreatment with GR125487, an antagonist for serotonin receptor subtype 4 (5-HT4R). An [(3)H] astemizole binding assay and electrophysiology experiments were performed to determine if PF-W has any interaction with the human ether-à-go-go related gene (hERG) potassium channel.

RESULTS

PF-W induced an increase in intracellular cAMP in 5-HT4R-expressing HEK293T cells, indicating that PF-W does activate 5-HT4R. Moreover, pretreatment with GR125487 successfully blocked the increase, suggesting that the response was 5-HT4R-specific. More importantly, pretreatment of GR125487 in rats inhibited the elevation of ITR by PF-W, indicating that the prokinetic effect of PF-W was indeed exerted via 5-HT4R. On the other hand, both [(3)H]-astemizole binding assay and electrophysiological experiments revealed that PF-W did not interfere at all with the hERG channel.

CONCLUSION

It was found that PF-W exerts its prokinetic activity through a 5-HT4R-mediated pathway, with no interaction with hERG channels. Therefore, PF-W is a good candidate that might be developed as a prokinetic agent with fewer expected cardiac side effects.

Anti-tumor effect of Liqi, a traditional Chinese medicine prescription, in tumor bearing mice

Background

Liqi, an herbal preparation used in traditional Chinese medicine, has been used to treat cancer in China for centuries. We investigated the anti-tumor effects of liqi and their mechanisms in mice that had been xenografted with tumors.

Methods

Sarcoma 180 tumor, Lewis lung carcinoma, and SGC-7901 cells were implanted in BALB/c mice, C57BL/6 mice, and BALB/c nude mice, respectively. Liqi was administered to subgroups of these mice. The tumor weight and size were measured. Cell cycle analysis and T lymphocyte subsets were determined by flow cytometry. The activity of NK cells and TNF was tested using cytotoxicity assay on YAC-1 cells and L929 cells, respectively, and the activity of IL-2 was tested with an IL-2-dependent CTLL-2 cell proliferation assay. Platelet aggregation was monitored by measuring electric impedance, and the levels of thromboxane A2 (TXA₂) and prostacyclin (PGI₂) in blood were measured by ¹²⁵I-TXB₂ and ¹²⁵I-Keto-PGF_1α radioimmunoassay.

Results

The results showed that liqi inhibited tumor growth in tumor-implanted mice and arrested the cell proliferation in the G0/G1 phase and reduced the portion of cells in S and G2/M phase for SGC-7901 cells. Liqi increased the activity of NK cells and TNF-α, stimulated IL-2 production and activity, and regulated T lymphocyte subpopulations. Liqi inhibited the Lewis lung carcinoma metastasis by inhibiting platelet aggregation and normalizing the balance between TXA₂ and PGI₂.

Conclusion

All these findings demonstrated that liqi has an anti-tumor effect in vivo. The mechanism may be related to immune regulation and anticoagulation effects.

One step purification of flavanone glycosides from Poncirus trifoliata by centrifugal partition chromatography

Flavanone glycosides were successfully separated from the crude extract of Poncirus trifoliata by preparative centrifugal partition chromatography with a two-phase solvent system composed of ethyl acetate-acetonitrile-water (3:2:5, v/v/v). Naringin (50.0 mg), neoponcirin (16.8 mg), and poncirin (71.9 mg) were purified from the 524 mg crude extract in only one step. The purities of the isolated compounds were determined to be over 90% by HPLC analysis and their structures were elucidated by (1)H NMR, (13)C NMR, and ESI-MS.

Inhibition of colon cancer cell growth and antioxidant activity of bioactive compounds from Poncirus trifoliata (L.) Raf

Recently several plant derived natural compounds have been screened for their anticancer activity in order to identify putative compounds with novel structures or mechanism of action. In the present study, fruits of Poncirus trifoliata were extracted with acetone and loaded onto silica gel column chromatography. The column was eluted with different solvents to obtain two bioactive compounds. The purity of compounds was analyzed by HPLC and their structures were identified by 1H and 13C NMR experiments as beta-sitosterol and 2-hydroxy-1,2,3-propanetricarboxylic acid 2-methyl ester (HPCME). beta-Sitosterol, HPCME, and trolox were tested for their antioxidant capacity by oxygen radical absorbance capacity (ORAC) measurement. Further, these compounds were tested for their inhibition of cancer cell proliferation and apoptosis using human colon cancer cell line (HT-29). These results were compared with the corresponding activity on non-cancerous (COS-1 fibroblast) cells. Cell proliferation and induction of apoptosis were determined by MTT assay and nuclear staining. The MTT assay indicated that both the compounds exhibited differential inhibition at various concentrations. Significant arrest of cell growth was observed with beta-sitosterol even at low concentration such as 0.63 microM in 48 h and none of the compounds exerted any apparent cytostatic effects on the non-cancerous COS-1 fibroblast cells. Growth inhibition assay suggested the potential use of bioactive compounds as cancer chemopreventive and therapeutic agents. This is the first report on HPCME isolation and identification from Rutaceae family and beta-sitosterol from P. trifoliata.

Effect of an aqueous extract of dried immature fruit of Poncirus trifoliata (L.) Raf. on intestinal transit in rodents with experimental gastrointestinal motility dysfunctions

The effect of an aqueous extract of the dried immature fruit of Poncirus trifoliata Raf. (Rutaceae) (PF-W) on gastrointestinal (GI) motor function was investigated by measuring the intestinal transit rate (ITR) of Evans blue in rats and mice with experimental GI motility dysfunctions (GMDs). GMD was induced by appropriate surgery or by the administration of acetic acid, atropine, L-DOPA, or morphine to the animals. The ITR in these GMD animals was significantly retarded compared to normal animals. The retardation, however, was significantly inhibited by the intragastric administration of PF-W (0.1-1g/kg) in a dose dependent manner for all GMD models except for L-DOPA-induced GMD. The above results suggest that PF-W has the potential for development as a prokinetic agent that may prevent or alleviate GMD in human patients.

Prokinetic activity of an aqueous extract from dried immature fruit of Poncirus trifoliata (L.) Raf

Aqueous extracts from dried immature fruit of Poncirus trifoliata Raf. (Rutaceae) (PF-W) are used as a traditional Korean folk medicine for the treatment of digestive dysfunction. In the present study, PF-W exhibited no significant toxicity even at a dose of 5 g/kg when orally administered to mice. The effect of PF-W on gastrointestinal (GI) motor function was investigated by examining its effect on the serum concentration of orally administered ranitidine, a putative indicator of GI motility, in human subjects. The area under the serum concentration-time curve and the peak serum concentration of ranitidine following an oral administration (300 mg/individual) were decreased by one half as the result of a predose (10 g/individual) of PF-W, except for the time to reach peak serum concentration and the serum half-life at the terminal phase of ranitidine. In rat studies, PF-W had no effect on the apparent permeability of ranitidine across the jejunum or the gastric emptying rate (GER) of phenol red. However, the transit time for charcoal in the intestine was significantly increased by the PF-W pretreatment. The above results are consistent with the hypothesis that PF-W has a unique prokinetic activity, which accelerates the transit of intestinal contents, but has no effect on the GER.

Methylene chloride fraction of Scutellaria barbata induces apoptosis in human U937 leukemia cells via the mitochondrial signaling pathway

BACKGROUND

Scutellaria barbata D.Don has been applied to treat cancers, inflammation and urinary disease. However, its antitumor mechanism still remains unclear.

METHODS

With methylene chloride fraction of Herba Scutellariae barbatae (MCSB), apoptosis-related experiments were carried out on human U937 leukemia cells by (a) 2,3-bis[2-4-nitro-5-sulphophenyl]2H-tetrazolium-5-carboxanilide (XTT) assay for cytotoxicity; (b) terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) assay for morphological changes; (c) cell cycle analysis; (d) Western blot analysis of poly(ADP-ribose) polymerase (PARP), caspase-8, caspase-9, caspase-3 and Bax, Bcl-2 and cytochrome c expressions for apoptosis signaling pathway.

RESULTS

MCSB inhibited the proliferation of human U937 leukemia cells in a dose-dependent manner (IC50 = approximately 10 microg/ml). MCSB dose-dependently increased the sub-G1 DNA contents by cell cycle analysis. DNA fragments indicating induction of apoptosis were observed in MCSB-treated U937 cells by TUNEL assay. Caspase-9 and caspase-3 were activated while caspase-8 was intact by MCSB. Similarly, MCSB effectively cleaved PARP, increased the ratio of Bax/Bcl-2 and released the cytochrome c from mitochondria during apoptosis in U937 cells.

CONCLUSIONS

Our results suggest that MCSB can induce apoptosis via the mitochondria-mediated signaling pathway.