Kamebakaurin Suppresses Antigen-Induced Mast Cell Activation by Inhibition of FcεRI Signaling Pathway.

INTRODUCTION: Kamebakaurin is an active constituent of both Rabdosia japonica and Rabdosia excisa, which are utilized in Chinese traditional medicine for improving symptoms in patients with allergies. We investigated the molecular mechanisms of the anti-allergic effects of kamebakaurin using BMMCs. METHODS: The degranulation ratio, histamine release, and the interleukin (IL)-4, leukotriene B4 (LTB4), and cysteinyl leukotriene productions on antigen-triggered BMMC were investigated. Additionally, the effects of kamebakaurin on signal transduction proteins were examined by Western blot and binding to the Syk and Lyn kinase domain was calculated. The effects of kamebakaurin on antigen-induced hyperpermeability were investigated using mouse model. RESULTS: At 10 µm, kamebakaurin partially inhibited degranulation, histamine release, and IL-4 production. At 30 µm, kamebakaurin partially reduced LTB4 and cysteinyl leukotriene productions and suppressed degranulation, histamine release, and IL-4 production. Phosphorylation of both Syk Y519/520 and its downstream protein, Gab2, was reduced by kamebakaurin, and complete inhibition was observed with 30 µm kamebakaurin. In contrast, phosphorylation of Erk was only partially inhibited, even in the presence of 30 µm kamebakaurin. Syk Y519/520 is known to be auto-phosphorylated via intramolecular ATP present in its own ATP-binding site, and this auto-phosphorylation triggers degranulation, histamine release, and IL-4 production. Docking simulation study indicated kamebakaurin blocked ATP binding to the ATP-binding site in Syk. Therefore, inhibition of Syk auto-phosphorylation by kamebakaurin binding to the Syk ATP-binding site appeared to cause a reduction of histamine release and IL-4 production. Kamebakaurin inhibited antigen-induced vascular hyperpermeability in a dose-dependent fashion but did not reduce histamine-induced vascular hyperpermeability. CONCLUSION: Kamebakaurin ameliorates allergic symptoms via inhibition of Syk phosphorylation; thus, kamebakaurin could be a lead compound for the new anti-allergic drug.

Synthesis of 1-O-acyl- and 1-oxo-kamebanin analogues and their cytotoxic activity.

A series of 1-O-acyl- and 1-oxo-kamebanin analogues were prepared from kamebanin, isolated from Rabdosia excisa and their cytotoxicity was assayed on HL60 promyelocytic leukemia cells and HCT116 human colon cancer cells. The structure-activity relationship study showed that the presence of 1-O-acyl groups of a C3-C5 carbon chain increased the cytotoxic activity.

R-Spondin2, a Positive Canonical WNT Signaling Regulator, Controls the Expansion and Differentiation of Distal Lung Epithelial Stem/Progenitor Cells in Mice.

The lungs have a remarkable ability to regenerate damaged tissues caused by acute injury. Many lung diseases, especially chronic lung diseases, are associated with a reduced or disrupted regeneration potential of the lungs. Therefore, understanding the underlying mechanisms of the regenerative capacity of the lungs offers the potential to identify novel therapeutic targets for these diseases. R-spondin2, a co-activator of WNT/ß-catenin signaling, plays an important role in embryonic murine lung development. However, the role of Rspo2 in adult lung homeostasis and regeneration remains unknown. The aim of this study is to determine Rspo2 function in distal lung stem/progenitor cells and adult lung regeneration. In this study, we found that robust Rspo2 expression was detected in different epithelial cells, including airway club cells and alveolar type 2 (AT2) cells in the adult lungs. However, Rspo2 expression significantly decreased during the first week after naphthalene-induced airway injury and was restored by day 14 post-injury. In ex vivo 3D organoid culture, recombinant RSPO2 promoted the colony formation and differentiation of both club and AT2 cells through the activation of canonical WNT signaling. In contrast, Rspo2 ablation in club and AT2 cells significantly disrupted their expansion capacity in the ex vivo 3D organoid culture. Furthermore, mice lacking Rspo2 showed significant defects in airway regeneration after naphthalene-induced injury. Our results strongly suggest that RSPO2 plays a key role in the adult lung epithelial stem/progenitor cells during homeostasis and regeneration, and therefore, it may be a potential therapeutic target for chronic lung diseases with reduced regenerative capability.

Single-Cell RNA Sequencing Analysis Reveals a Crucial Role for CTHRC1 (Collagen Triple Helix Repeat Containing 1) Cardiac Fibroblasts After Myocardial Infarction.

BACKGROUND: Cardiac fibroblasts (CFs) have a central role in the ventricular remodeling process associated with different types of fibrosis. Recent studies have shown that fibroblasts do not respond homogeneously to heart injury. Because of the limited set of bona fide fibroblast markers, a proper characterization of fibroblast population heterogeneity in response to cardiac damage is lacking. The purpose of this study was to define CF heterogeneity during ventricular remodeling and the underlying mechanisms that regulate CF function. METHODS: Collagen1α1-GFP (green fluorescent protein)-positive CFs were characterized after myocardial infarction (MI) by single-cell and bulk RNA sequencing, assay for transposase-accessible chromatin sequencing, and functional assays. Swine and patient samples were studied using bulk RNA sequencing. RESULTS: We identified and characterized a unique CF subpopulation that emerges after MI in mice. These activated fibroblasts exhibit a clear profibrotic signature, express high levels of Cthrc1 (collagen triple helix repeat containing 1), and localize into the scar. Noncanonical transforming growth factor-ß signaling and different transcription factors including SOX9 are important regulators mediating their response to cardiac injury. Absence of CTHRC1 results in pronounced lethality attributable to ventricular rupture. A population of CFs with a similar transcriptome was identified in a swine model of MI and in heart tissue from patients with MI and dilated cardiomyopathy. CONCLUSIONS: We report CF heterogeneity and their dynamics during the course of MI and redefine the CFs that respond to cardiac injury and participate in myocardial remodeling. Our study identifies CTHRC1 as a novel regulator of the healing scar process and a target for future translational studies.

Five New Triterpenoid Saponins from the Rhizomes of Panacis majoris and Their Antiplatelet Aggregation Activity.

Five new triterpenoid saponins (1-5) and four known triterpenoid saponins, ginsenoside Re5 (6), majonoside R1 (7), 24(R)-majonoside R1 (8), and ginsenoside Rf (9), were isolated from the rhizomes of Panacis majoris. The structures of new compounds were elucidated as (20S,24S,25R*)-6-O-[ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyl]-dammar-20,24-epoxy-3ß,6α,12ß,25,26-pentaol (1), (20S,24R,25R)-6-O-[ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyl]-dammar-20,24-epoxy-3ß,6α,12ß,25,26-pentaol (2), (20S)-6-O-[ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyl]-dammar-20,25-epoxy-3ß,6α,12ß,24α-tetraol (3), 6-O-[ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyl]-dammar-3ß,6α,12ß,20S,24R,25-hexaol (4), and 6-O-[ß-D-glucop-yranosyl-(1 → 2)-ß-D-glucopyranosyl]-dammar-25(26)-ene-3ß,6α,12ß,20S,24R-pentaol (5) on the basis of extensive spectral analysis and chemical methods. Ginsenoside Re5 was isolated from the plant for the first time. The similarities of the nine compounds lie in the fact that their aglycones are conjoined with the same glucopyranose moieties, the same linkage of the glycosyl chains, and the same glycosylation sites, while they have a varied C-17 side chain. Compounds 3 and 5 exhibited moderate antiplatelet aggregation activities induced by adenosine diphosphate with IC50 values of 23.24 and 18.43 µM, respectively. Compound 5 displayed moderate inhibition of arachidonic acid-induced platelet aggregation with an IC50 value of 30.11 µM.

Wnt9b-dependent FGF signaling is crucial for outgrowth of the nasal and maxillary processes during upper jaw and lip development.

Outgrowth and fusion of the lateral and medial nasal processes and of the maxillary process of the first branchial arch are integral to lip and primary palate development. Wnt9b mutations are associated with cleft lip and cleft palate in mice; however, the cause of these defects remains unknown. Here, we report that Wnt9b(-/-) mice show significantly retarded outgrowth of the nasal and maxillary processes due to reduced proliferation of mesenchymal cells, which subsequently results in a failure of physical contact between the facial processes that leads to cleft lip and cleft palate. These cellular defects in Wnt9b(-/-) mice are mainly caused by reduced FGF family gene expression and FGF signaling activity resulting from compromised canonical WNT/ß-catenin signaling. Our study has identified a previously unknown regulatory link between WNT9B and FGF signaling during lip and upper jaw development.

Ionic liquid and aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of seven rare ginsenosides in Xue-Sai-Tong injection.

A method of ionic liquid salt aqueous two-phase extraction coupled with high-performance liquid chromatography has been developed for the analysis of seven rare ginsenosides including Rg6 , F4 , 20(S)-Rg3 , 20(R)-Rg3 , Rk3 , Rk1 , and Rg5 in Xue-Sai-Tong injection. The injection was mixed with ionic liquid 1-butyl-3-methylimidazolium bromide aqueous solution, and a mixture was obtained. With the addition of sodium dodecyl sulfate and dipotassium phosphate into the mixture, the aqueous two-phase mixture was formed after ultrasonic treatment and centrifuged. Rare ginsenosides were extracted into the upper phase. To obtain a high extraction factors, various influences were considered systematically, such as the volume of ionic liquid, the category and amount of salts, the amount of sodium dodecyl sulfate, the pH value of system, and the time of ultrasonic treatment. Under the optimal condition, rare ginsenosides in Xue-Sai-Tong injection were enriched and detected, the recoveries of seven rare ginsenosides ranged from 90.05 to 112.55%, while relative standard deviations were lower than 2.50%. The developed method was reliable, rapid and sensitive for the determination of seven rare ginsenosides in the injections.

The canonical Wnt signaling activator, R-spondin2, regulates craniofacial patterning and morphogenesis within the branchial arch through ectodermal-mesenchymal interaction.

R-spondins are a recently characterized family of secreted proteins that activate Wnt/ß-catenin signaling. Herein, we determine R-spondin2 (Rspo2) function in craniofacial development in mice. Mice lacking a functional Rspo2 gene exhibit craniofacial abnormalities such as mandibular hypoplasia, maxillary and mandibular skeletal deformation, and cleft palate. We found that loss of the mouse Rspo2 gene significantly disrupted Wnt/ß-catenin signaling and gene expression within the first branchial arch (BA1). Rspo2, which is normally expressed in BA1 mesenchymal cells, regulates gene expression through a unique ectoderm-mesenchyme interaction loop. The Rspo2 protein, potentially in combination with ectoderm-derived Wnt ligands, up-regulates Msx1 and Msx2 expression within mesenchymal cells. In contrast, Rspo2 regulates expression of the Dlx5, Dlx6, and Hand2 genes in mesenchymal cells via inducing expression of their upstream activator, Endothelin1 (Edn1), within ectodermal cells. Loss of Rspo2 also causes increased cell apoptosis, especially within the aboral (or caudal) domain of the BA1, resulting in hypoplasia of the BA1. Severely reduced expression of Fgf8, a survival factor for mesenchymal cells, in the ectoderm of Rspo2(-/-) embryos is likely responsible for increased cell apoptosis. Additionally, we found that the cleft palate in Rspo2(-/-) mice is not associated with defects intrinsic to the palatal shelves. A possible cause of cleft palate is a delay of proper palatal shelf elevation that may result from the small mandible and a failure of lowering the tongue. Thus, our study identifies Rspo2 as a mesenchyme-derived factor that plays critical roles in regulating BA1 patterning and morphogenesis through ectodermal-mesenchymal interaction and a novel genetic factor for cleft palate.

A WNT/beta-catenin signaling activator, R-spondin, plays positive regulatory roles during skeletal myogenesis.

R-spondins (RSPOs) are a recently characterized family of secreted proteins that activate WNT/ß-catenin signaling. In this study, we investigated the potential roles of the RSPO proteins during myogenic differentiation. Overexpression of the Rspo1 gene or administration of recombinant RSPO2 protein enhanced mRNA and protein expression of a basic helix-loop-helix (bHLH) class myogenic determination factor, MYF5, in both C2C12 myoblasts and primary satellite cells, whereas MYOD or PAX7 expression was not affected. RSPOs also promoted myogenic differentiation and induced hypertrophic myotube formation in C2C12 cells. In addition, Rspo2 and Rspo3 gene knockdown by RNA interference significantly compromised MYF5 expression, myogenic differentiation, and myotube formation. Furthermore, Myf5 expression was reduced in the developing limbs of mouse embryos lacking the Rspo2 gene. Finally, we demonstrated that blocking of WNT/ß-catenin signaling by DKK1 or a dominant-negative form of TCF4 reversed MYF5 expression, myogenic differentiation, and hypertrophic myotube formation induced by RSPO2, indicating that RSPO2 exerts its activity through the WNT/ß-catenin signaling pathway. Our results provide strong evidence that RSPOs are key positive regulators of skeletal myogenesis acting through the WNT/ß-catenin signaling pathway.

Ursolic acid enhances mouse liver regeneration after partial hepatectomy.

CONTEXT: Ursolic acid is a pentacyclic triterpenoid which has hepatoprotective and antihepatotoxic activities. OBJECTIVE: This study investigated whether ursolic acid is able to stimulate liver regeneration in partially hepatectomized mice. MATERIALS AND METHODS: Ursolic acid or the vehicle solution was orally administered to the experimental, sham-operated and vehicle-treated group mice for 7 days, positive control animal (mice) was treated with recombinant human hepatocyte growth factor (rhHGF), and then the 70% liver partial hepatectomy was performed. The liver mass recovery rate was estimated by measuring the ratios of mice liver weight to body weight. The liver cells undergoing DNA synthesis were identified by immunohistochemistry analysis using monoclonal anti-BrdU antibodies. The expression levels of cyclin D1, cyclin E and C/EBP proteins (C/EBPα and C/EBPß) were detected by the Western blotting technique. RESULTS: Our results showed administration of ursolic acid significantly increased the ratio of the liver to body weight and BrdU labeling index at 36 and 48 h after partial hepatectomy, and the potency of UA is similar to rhHGF treated positive control mice. In addition, ursolic acid treatment significantly increased cyclin D1, cyclin E and C/EBPß protein expression levels at 36 h after liver PHx compared with the vehicle-treated control mice. DISCUSSION AND CONCLUSION: All these results suggest that ursolic acid stimulates liver proliferation after partial hepatectomy, and this effect may be associated with the stimulation of C/EBPß expression.

Synthesis of rabdokunmin C analogues and their inhibitory effect on NF-κB activation.

A series of rabdokunmin C analogues were prepared and their inhibitory effect on NF-κB activation was assayed. One of them, 18-acetyl-12-deoxy-11,12-dehydrorabdokunmin C (16) was found to be a promising candidate for an anti-inflammatory agent.

Three new dammarane-type triterpene saponins from the leaves of Panax ginseng C.A. Meyer.

Three new dammarane-type triterpene ginsenosides, together with six known ginsenosides, were isolated from the leaves of Panax ginseng C.A. Meyer. The new saponins were named as ginsenoside Rh11, ginsenoside Rh12, and ginsenoside Rh13. Their structures were elucidated as (20S)-3ß,6α,12ß,20-tetrahydroxydammara-25-ene-24-one 20-O-ß-d-glucopyranoside (1), (20S)-3ß,12ß,20,24,25-pentahydroxydammarane 20-O-ß-d-glucopyranoside (2), and (20S,23E)-3ß,12ß,20,25-tetrahydroxydammara-23-ene 20-O-ß-d-glucopyranoside (3) on the basis of 1D and 2D NMR experiments and mass spectra. The known ginsenosides were identified as ginsenoside M(7cd), ginsenoside Rg6, ginsenoside Rb3, gypenoside XVII, gypenoside IX, and 20-(E)-ginsenoside F4.

Canonical WNT/ß-Catenin Signaling Activated by WNT9b and RSPO2 Cooperation Regulates Facial Morphogenesis in Mice.

The R-spondin (RSPO) family of proteins potentiate canonical WNT/ß-catenin signaling and may provide a mechanism to fine-tune the strength of canonical WNT signaling. Although several in vitro studies have clearly demonstrated the potentiation of canonical WNT signaling by RSPOs, whether this potentiation actually occurs in normal development and tissue function in vivo still remains poorly understood. Here, we provide clear evidence of the potentiation of canonical WNT signaling by RSPO during mouse facial development by analyzing compound Wnt9b and Rspo2 gene knockout mice and utilizing ex vivo facial explants. Wnt9b;Rspo2 double mutant mice display facial defects and dysregulated gene expression pattern that are significantly more severe than and different from those of Wnt9b or Rspo2 null mutant mice. Furthermore, we found suggestive evidence that the LGR4/5/6 family of the RSPO receptors may play less critical roles in WNT9b:RSPO2 cooperation. Our results suggest that RSPO-induced cooperation is a key mechanism for fine-tuning canonical WNT/ß-catenin signaling in mouse facial development.

Hesperetin, a bioflavonoid, inhibits rat aortic vascular smooth muscle cells proliferation by arresting cell cycle.

Diet can be one of the most important factors that influence risks for cardiovascular diseases. Hesperetin, a flavonoid present in grapefruits and oranges, is one candidate that may benefit the cardiovascular system. In this study, we have investigated the effect of hesperetin on the platelet-derived growth factor (PDGF)-BB-induced proliferation of primary cultured rat aortic vascular smooth muscle cells (VSMCs). Hesperetin significantly inhibited 50 ng/ml PDGF-BB-induced rat aortic VSMCs proliferation and [(3)H]-thymidine incorporation into DNA at concentrations of 5, 25, 50, and 100 microM. In accordance with these findings, hesperetin revealed blocking of the PDGF-BB-inducible progression through G(0)/G(1) to S phase of the cell cycle in synchronized cells. Western blot showed that hesperetin inhibited not only phosphorylation of retinoblastoma protein (pRb) and expressions of cyclin A, cyclin D, cyclin E, cyclin-dependent kinase 2 (CDK2) as well as proliferating cell nuclear antigen (PCNA) protein, but also downregulation of cyclin-dependent kinase inhibitor (CKI) p27(kip1), while did not affect CKI p21(cip1), p16(INK4), p53, and CDK4 expressions as well as early signaling transductions such as PDGF beta-receptor, extracellular signal-regulated kinase (ERK) 1/2, Akt, p38, and JNK phosphorylation. These results suggest that hesperetin inhibits PDGF-BB-induced rat aortic VSMCs proliferation via G(0)/G(1) arrest in association with modulation of the expression or activation of cell-cycle regulatory proteins, which may contribute to the beneficial effect of grapefruits and oranges on cardiovascular system.

YSK2821, a newly synthesized indoledione derivative, inhibits cell proliferation and cell cycle progression via the cell cycle-related proteins by regulating phosphatidylinositol-3 kinase cascade in vascular smooth muscle cells.

Indoledione derivatives have pronounced biological effects, i.e., cytotoxic activities against cancer cell lines and antifungal and antibacterial activities. The present study was designed to investigate the effects of YSK2821, a newly synthesized indoledione derivative, on platelet-derived growth factor (PDGF-BB)-induced vascular smooth muscle cell (VSMC) proliferation, as well as the molecular mechanisms of the anti-proliferative effects of YSK2821 in VSMCs. We found that YSK2821 caused the accumulation of cells in the G1 phase of the cell cycle and inhibited [3H]-thymidine incorporation. We demonstrated that YSK2821 remarkably decreased Akt kinase phosphorylation as the mechanism by which YSK2821 suppressed cell signal transduction events in VSMC proliferation. Furthermore, in terms of the effects of YSK2821 on cell cycle-related proteins, YSK2821 enhanced the expression of the cyclin-dependent protein kinase (CDK) inhibitor p27 and down-regulated CDK2 and cyclin E expression, but did not affect CDK4 and cyclin D1 expression. YSK2821 also inhibited the phosphorylation of Rb, a key regulator in the cell cycle. These results indicate that YSK2821, a newly synthesized indoledione derivative, may inhibit VSMC proliferation via a phosphatidylinositol (PI)-3 kinase-dependent pathway, and thus shed light on a novel role for YSK2821 as a potential preventive regulator of cardiovascular disease.

1O, 20O-diacetyl kamebakaurin protects against acetaminophen-induced hepatotoxicity in mice.

The present study aimed to investigate the protective effects of kamebakaurin (KA) and 1O, 20O-diacetyl kamebakaurin (Ac2KA) on acetaminophen (APAP)-induced hepatotoxicity and compare the hepatoprotective mechanisms of the two chemicals. Seven-week-old male C57BL/6J mice were orally administered KA, Ac2KA, or an ethanol/olive oil emulsion once per day for 7-days. Twenty-four hours after the final administration, the mice were fasted and then intraperitoneally injected with 450 mg/kg APAP or saline. At 16 h after injection, the mice were euthanized and blood samples were collected for plasma analysis. Pretreatment with KA and Ac2KA significantly attenuated APAP-induced hepatic injury. The protective effect of Ac2KA was stronger than that of KA. These two chemicals attenuated oxidative stress, inflammatory cytokine production, c-jun N-terminal kinase activation, and receptor-interacting protein (RIP)-3 activation. Ac2KA also decreased APAP-induced RIP-1 activation and nuclear factor kappa B (NF-κB) p65 translocation. Moreover, Ac2KA repressed mRNA expression of Cyp1a2/2e1 in the liver. Our results showed that KA and Ac2KA exerted protective effects against APAP-induced hepatotoxicity. The responsible mechanisms may be related to the chemicals' antioxidant activity and the inhibition of c-jun N-terminal kinase activation and RIP-3 activation. The effects of Ac2KA included those of KA, as well as RIP-1 inactivation, NF-κB inhibition, and Cyp inhibition.

Epothilone D, a microtubule-stabilizing compound, inhibits neointimal hyperplasia after rat carotid artery injury by cell cycle arrest via regulation of G1-checkpoint proteins.

Epothilone D (Epo-D) is a paclitaxel-like microtubule-stabilizing agent that was isolated from the myxobacterium Sorangium cellulosum. Although Epo-D can inhibit proliferation in multiple tumor cell lines, the effect of Epo-D on neointimal hyperplasia after angioplasty has not been reported. The aim of the present study was to investigate the effects of Epo-D on neointimal hyperplasia using an in vivo rat carotid artery injury model. We demonstrated that local Epo-D treatment significantly reduced neointimal hyperplasia after in vivo rat carotid artery injury, and Epo-D potently inhibited DNA synthesis, cell cycle progression and cell proliferation after FBS- and PDGF-BB-stimulation; PDGF-BB has been identified as the most potent growth factor for stimulating the proliferation of activated rat aortic smooth muscle cells (RASMCs). To clarify the specific effects of Epo-D on cell cycle machinery, we examined its effects on cyclin-dependent kinase (CDK)2, CDK4, cyclin E, p27, and retinoblastoma (Rb) proteins as cell cycle-related proteins in cellular lysates from PDGF-BB-stimulated RASMCs. Epo-D treatment significantly decreased the level of CDK2 protein, but did not change the levels of CDK4 and cyclin E proteins. Furthermore, Epo-D inhibited the phosphorylation of Rb, a key regulator of the G1 to S phase transition in the cell cycle. These findings suggest that Epo-D may regulate the cell cycle G1-checkpoint proteins as its major molecular mechanism for inhibiting neointimal hyperplasia after in vivo rat carotid artery injury.

Antithrombotic and antiplatelet activities of Korean red ginseng extract.

The antithrombotic and antiplatelet activities of Korean red ginseng extract (KRGE) were examined on rat carotid artery thrombosis in vivo and platelet aggregation in vitro and ex vivo. The KRGE significantly prevented rat carotid arterial thrombosis in vivo in a dose-dependent manner. Administration of the KRGE to rats significantly inhibited adenosine diphosphate (ADP)- and collagen-induced platelet aggregation ex vivo, although it failed to prolong coagulation times such as activated partial thromboplastin and prothrombin time indicating that the antithrombotic effect of the red ginseng may be due to its antiplatelet aggregation rather than anticoagulation effect. In line with the above observations, the red ginseng inhibited the U46619-, arachidonic acid-, collagen- and thrombin-induced rabbit platelet aggregations in vitro in a concentration-dependent manner, with IC(50) values of 390 +/- 15, 485 +/- 19, 387 +/- 11 and 335 +/- 15 microg/ml, respectively. Consistently, serotonin secretion was also inhibited by ginseng in the same pattern. These results suggest that the red ginseng has a potent antithrombotic effect in vivo, which may be due to the antiplatelet rather than the anticoagulation activity, and the red ginseng intake may be beneficial for individuals with high risks of thrombotic and cardiovascular diseases.

Oleanolic acid, a pentacyclic triterpenoid, induces rabbit platelet aggregation through a phospholipase C-calcium dependent signaling pathway.

Oleanolic acid (3beta-hydroxy-olea-12-en-28-oic), a pentacyclic triterpenoid, exists widely in the plant kingdom and has a wide variety of pharmacological effects such as antitumor, antifungal, insecticidal, hepatoprotective and anti-HIV activities. This paper reports that oleanolic acid induces the aggregation of rabbit platelets, a mechanism was also investigated. Oleanolic acid at concentrations of 25, 50, 100 and 200 microM induced the aggregation of washed rabbit platelets in a concentration-dependent manner. Pretreating the platelets with U73122, a phospholipase C (PLC) inhibitor, blocked the oleanolic acid induced-aggregation, whereas acetylsalicylic acid (ASA), a cyclooxygenase (COX) inhibitor, had no effect. In addition, the effect of oleanolic acid on serotonin secretion, which is a marker for dense granule secretion, was determined. Oleanolic acid induced serotonin secretion in a similar concentration-dependent manner as observed with platelet aggregation. Pretreating the platelets with U73122 blocked the oleanolic acid-induced serotonin secretion and cytosolic calcium mobilization. Overall, these results suggest that oleanolic acid can induce platelet aggregation, which may be mediated by the stimulation of PLC-mediated cytosolic calcium mobilization.

[Study on variation of actinoside C in leaves of Actinidia kolomikta with different growth periods by RP-HPLC].

OBJECTIVE: To determine actinoside C in the leaves of Actinidia kolomikta with different growth periods. METHOD: The separation was performed at 25 degrees C on ZORBAX Extend C18 column (4.6 mm x 250 mm, 5 microm), using amixture of methanol and water (51:49) as a mobile phase. The flow rate was 1.2 mL x min(-1), and the wavelength for measurement was 267 nm. RESULT: The results showed that the contents of actinoside C in the leaves of A. kolomikta were variety in different growth periods. Actinoside C could reach its highest content in the middle ten days of June, then the content would decrease in the middle ten days of July slightly, it could reach their lowest content in the middle ten days of August. CONCLUSION: The optimal collective date for A. kolomikta are in the middle ten days of June.