Human ACAT-1 and ACAT-2 inhibitory activities of pentacyclic triterpenes from the leaves of Lycopus lucidus TURCZ

Pimarane Diterpenoids from Aerial Parts of Lycopus lucidus and Their Antimicrobial Activity

The ethyl acetate fraction obtained from aerial parts of L. lucidus was subjected for isolation of new bioactive compounds, which enabled isolation of five new pimarane-type diterpenoids, namely, 3β, 8β, 12β, 18-tetrahydroxy pimar-15-ene (10), 7α, 8β, 12β, 18-tetrahydroxy pimar-15-ene (11), 3β, 8β, 11β, 12α, 18-pentahydroxy pimar-15-ene (12), 12β acetoxy, 8β, 3β, 18-trihydroxy pimar-15-ene (13), and 3β acetoxy, 8β, 12β, 18-trihydroxy pimar-15-ene (14), along with nine known compounds. The structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new pimarane diterpenoids were examined for antimicrobial activity against Gram-negative and Gram-positive bacteria strains. Among them, the compound 3β, 8β, 12β, 18-tetrahydroxy pimar-15-ene (10) was most effective, exhibiting minimum inhibitory concentration (MIC) values of 15.62 µg/mL against Staphylococcus epidermidis, 31.25 µg/mL against Staphylococcus aureus, 62.5 µg/mL against Pseudomonas aeruginosa, and 125 µg/mL against Escherichia coli.

Oleanolic Acid: Extraction, Characterization and Biological Activity

Oleanolic acid, a pentacyclic triterpenoid ubiquitously present in the plant kingdom, is receiving outstanding attention from the scientific community due to its biological activity against multiple diseases. Oleanolic acid is endowed with a wide range of biological activities with therapeutic potential by means of complex and multifactorial mechanisms. There is evidence suggesting that oleanolic acid might be effective against dyslipidemia, diabetes and metabolic syndrome, through enhancing insulin response, preserving the functionality and survival of β-cells and protecting against diabetes complications. In addition, several other functions have been proposed, including antiviral, anti-HIV, antibacterial, antifungal, anticarcinogenic, anti-inflammatory, hepatoprotective, gastroprotective, hypolipidemic and anti-atherosclerotic activities, as well as interfering in several stages of the development of different types of cancer; however, due to its hydrophobic nature, oleanolic acid is almost insoluble in water, which has led to a number of approaches to enhance its biopharmaceutical properties. In this scenario, the present review aimed to summarize the current knowledge and the research progress made in the last years on the extraction and characterization of oleanolic acid and its biological activities and the underlying mechanisms of action.

Modulation of Lipid Transport and Adipose Tissue Deposition by Small Lipophilic Compounds

Small lipophilic molecules present in foods of plant origin have relevant biological activities at rather low concentrations. Evidence suggests that phytosterols, carotenoids, terpenoids, and tocopherols can interact with different metabolic pathways, exerting beneficial effects against a number of metabolic diseases. These small molecules can modulate triacylglycerol absorption in the intestine and the biosynthesis of chylomicrons, the lipid carriers in the blood. Once in the bloodstream, they can impact lipoprotein clearance from blood, thereby affecting fatty acid release, incorporation into adipocytes and triglyceride reassembling and deposit. Consequently, some of these molecules can regulate pathophysiological processes associated to obesity and its related conditions, such as insulin resistance, metabolic syndrome and type-2 diabetes. The protective capacity of some lipophilic small molecules on oxidative and chemotoxic stress, can modify the expression of key genes in the adaptive cellular response, such as transcription factors, contributing to prevent the inflammatory status of adipose tissue. These small lipophilic compounds can be incorporated into diet as natural parts of food but they can also be employed to supplement other dietary and pharmacologic products as nutraceuticals, exerting protective effects against the development of metabolic diseases in which inflammation is involved. The aim of this review is to summarize the current knowledge of the influence of dietary lipophilic small biomolecules (phytosterols, carotenoids, tocopherols, and triterpenes) on lipid transport, as well as on the effects they may have on pathophysiological metabolic states, related to obesity, insulin resistance and inflammation, providing an evidence-based summary of their main beneficial effects on human health.

Ameliorative Effects and Cellular Aspects of Phytoconstituents in Atherosclerosis

Atherosclerosis is a cardiovascular disease that involves vessels through the development of fatty streaks and plaques. Plant-based compounds can help treat or prevent atherosclerosis by affecting various factors that are involved in the disease. The present review discusses our current knowledge of the major cellular and molecular mechanisms of phytotherapeutics for the treatment of atherosclerosis. Numerous studies have evaluated the antiatherosclerotic activity of phytoconstituents to provide preliminary evidence of efficacy, but only a few studies have delineated the underlying molecular mechanisms. Plant-derived phytotherapeutics primarily targets abnormal levels of lipoproteins, endothelial dysfunction, smooth muscle cell migration, foam cell development, and atheromatous plaque formation. Nonetheless, the principal mechanisms that are responsible for their therapeutic actions remain unclear. Further pharmacological studies are needed to elucidate the underlying molecular mechanisms of the antiatherosclerotic response to these phytoconstituents.

Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products

Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.

Betulin and its derivatives as novel compounds with different pharmacological effects

Betulin (B) and Betulinic acid (BA) are natural pentacyclic lupane-structure triterpenoids which possess a wide range of pharmacological activities. Recent evidence indicates that B and BA have several properties useful for the treatment of metabolic disorders, infectious diseases, cardiovascular disorders, and neurological disorders. In the current review, we discuss B and BA structures and derivatives and then comprehensively explain their pharmacological effects in relation to various diseases. We also explain antiviral, antibacterial and anti-cancer effects of B and BA. Finally, we discuss the delivery methods, in which these compounds most effectively target different systems.

Bryonolic Acid Blocks Cancer Cell Clonogenicity and Invasiveness through the Inhibition of Fatty Acid: Cholesteryl Ester Formation

Bryonolic acid (BrA) is a pentacyclic triterpene present in several plants used in African traditional medicine such as Anisophyllea dichostyla R. Br. Here we investigated the in vitro anticancer properties of BrA. We report that BrA inhibits acyl-coA: cholesterol acyl transferase (ACAT) activity in rat liver microsomes in a concentration-dependent manner, blocking the biosynthesis of the cholesterol fatty acid ester tumour promoter. We next demonstrated that BrA inhibits ACAT in intact cancer cells with an IC₅₀ of 12.6 ± 2.4 µM. BrA inhibited both clonogenicity and invasiveness of several cancer cell lines, establishing that BrA displays specific anticancer properties. BrA appears to be more potent than the other pentacyclic triterpenes, betulinic acid and ursolic acid studied under similar conditions. The inhibitory effect of BrA was reversed by exogenous addition of cholesteryl oleate, showing that ACAT inhibition is responsible for the anticancer effect of BrA. This report reveals new anticancer properties for BrA.

Competitive affinity-based proteome profiling and imaging to reveal potential cellular targets of betulinic acid

Affinity-based proteome profiling (AfBP) coupled with bioimaging to uncover cellular targets of betulinic acid.

Oleanolic, Ursolic, and Betulinic Acids as Food Supplements or Pharmaceutical Agents for Type 2 Diabetes: Promise or Illusion?

Oleanolic (OA), ursolic (UA), and betulinic (BA) acids are three triterpenic acids (TAs) with potential effects for treatment of type 2 diabetes (T2DM). Mechanistic studies showed that these TAs act as hypoglycemic and antiobesity agents mainly through (i) reducing the absorption of glucose; (ii) decreasing endogenous glucose production; (iii) increasing insulin sensitivity; (iv) improving lipid homeostasis; and (v) promoting body weight regulation. Besides these promising beneficial effects, it is believed that OA, UA, and BA protect against diabetes-related comorbidities due to their antiatherogenic, anti-inflammatory, and antioxidant properties. We also highlight the protective effect of OA, UA, and BA against oxidative damage, which may be very relevant for the treatment and/or prevention of T2DM. In the present review, we provide an integrative description of the antidiabetic properties of OA, UA, and BA, evaluating the potential use of these TAs as food supplements or pharmaceutical agents to prevent and/or treat T2DM.

In vitro anticancer activity of Betulinic acid and derivatives thereof on equine melanoma cell lines from grey horses and in vivo safety assessment of the compound NVX-207 in two horses

Betulinic acid, a pentacyclic triterpene, and its derivatives are promising compounds for cancer treatment in humans. Melanoma is not only a problem for humans but also for grey horses as they have a high potential of developing melanoma lesions coupled to the mutation causing their phenotype. Current chemotherapeutic treatment carries the risk of adverse health effects for the horse owner or the treating veterinarian by exposure to antineoplastic compounds. Most treatments have low prospects for systemic tumor regression. Thus, a new therapy is needed. In this in vitro study, Betulinic acid and its two derivatives B10 and NVX-207, both with an improved water solubility compared to Betulinic acid, were tested on two equine melanoma cell lines (MelDuWi and MellJess/HoMelZh) and human melanoma (A375) cell line. We could demonstrate that all three compounds especially NVX-207 show high cytotoxicity on both equine melanoma cell lines. The treatment with these compounds lead to externalization of phosphatidylserines on the cell membrane (AnnexinV-staining), DNA-fragmentation (cell cycle analysis) and activation of initiator and effector caspases (Caspase assays). Our results indicate that the apoptosis is induced in the equine melanoma cells by all three compounds. Furthermore, we succeed in encapsulating the most active compound NVX-207 in 2-Hydroxyprolyl-β-cyclodextrine without a loss of its activity. This formulation can be used as a promising antitumor agent for treating grey horse melanoma. In a first tolerability evaluation in vivo the formulation was administered every one week for 19 consecutive weeks and well tolerated in two adult melanoma affected horses.

Synthesis of heterocycle-modified betulinic acid derivatives as antitumor agents

A series of novel heterocycle-modified betulinic acid (BA) derivatives were synthesized and investigated for their activity against the growth of eight non-drug resistant and one multidrug-resistant tumor cell line using a sulforhodamine B (SRB) assay. The most active compound 17 showed an average IC50 1.19 μM, which was about 20 times more potent than the lead compound BA. It is amazing that for most synthetic saturated N-heterocycle derivatives, MCF-7/ADR was the most sensitive tumor cells, especially 17 showed the most potent antitumor activity (IC50 = 0.33 μM) on this multidrug-resistant tumor cell line, that was 117 times more potent than BA. Most of the tested compounds displayed less toxic on human fibroblasts (HAF) in comparison with the tumor cell lines. The cytometry and transwell migration assays were used to test the ability of 17 to induce apoptosis and inhibit metastasis on tumor cell lines respectively.

Triterpenoids from the fruits and leaves of the blackberry (Rubus allegheniensis) and their inhibitory activities on foam cell formation in human monocyte-derived macrophage

From the methanol extract of the fruits of the blackberry (Rubus allegheniensis Port.), four triterpenoids - pomolic acid (1), tormentic acid (2), euscaphic acid (3) and 1β-hydroxyeuscaphic acid (4) - were isolated, while six triterpenoids - 2, 3, myrianthic acid (5), ziyu glycoside II (6), sericic acid (7) and 19-hydroxy-2,3-secours-12-ene-2,3,28-trioic acid 3-methyl ester (8) - were obtained from the methanol extract of the leaves of this plant. Their structures were determined on the basis of spectral data. Compounds 1-8 were examined for their inhibitory activities on foam cell formation in human monocyte-derived macrophages induced by acetylated low-density lipoproteins at a 50 μM concentration. Among the tested compounds, 1 showed the strongest activity, with the inhibitory effect being 90%. The inhibitory activities of 2-8 were evaluated to be 30%, 32%, 33%, 4%, 48%, 4% and 24%, respectively. Further, the structure-activity relationship of these compounds was investigated.

Antidiabetic and antihyperlipidemic activity of asiatic acid in diabetic rats, role of HMG CoA: in vivo and in silico approaches

Hyperlipidemia is an associated complication of diabetes and also a major risk factor for cardiovascular diseases. The present study was designed to examine the antihyperlipidemic effect of asiatic acid (AA) in streptozotocin (STZ) induced diabetic rats. Diabetes was induced in male Wistar rats by a single intraperitoneal injection of STZ (40 mg/kg b.w.). Diabetic rats show increased plasma glucose, total cholesterol, triglycerides, free fatty acids, phospholipids, low density lipoprotein, very low density liprotein, atherogenic index and decreased insulin and high density lipoprotein in diabetic rats. The activity of 3-hydroxy 3-methylglutaryl coenzyme A (HMG CoA) reductase increased significantly in contrast to the activities of lipoprotein lipase and lecithin cholesterol acyltransferase. In addition, the molecular docking of AA against HMG CoA reductase involved in cholesterol biosynthesis using Argus software. Diabetic rats were treated with AA shifted all these parameters towards normalcy. AA has shown best ligand binding energy 11.8122 kcal/mol. The antihyperlipidemic effect of AA was compared with glibenclamide; a well-known antihyperglycemic drug. In conclusion, this study indicates that AA showed an antihyperlipidemic effect in addition to its antidiabetic effect in experimental diabetes.

Biochemical basis of the antidiabetic activity of oleanolic acid and related pentacyclic triterpenes

Oleanolic acid (OA), a natural component of many plant food and medicinal herbs, is endowed with a wide range of pharmacological properties whose therapeutic potential has only partly been exploited until now. Throughout complex and multifactorial mechanisms, OA exerts beneficial effects against diabetes and metabolic syndrome. It improves insulin response, preserves functionality and survival of β-cells, and protects against diabetes complications. OA may directly modulate enzymes connected to insulin biosynthesis, secretion, and signaling. However, its major contributions appear to be derived from the interaction with important transduction pathways, and many of its effects are consistently related to activation of the transcription factor Nrf2. Doing that, OA induces the expression of antioxidant enzymes and phase II response genes, blocks NF-κB, and represses the polyol pathway, AGEs production, and hyperlipidemia. The management of type 2 diabetes requires an integrated approach, which includes the early intervention to prevent or delay the disease progression, and the use of therapies to control glycemia and lipidemia in its late stages. In this sense, the use of functional foods or drugs containing OA is, undoubtedly, an interesting path.

New ionic derivatives of betulinic acid as highly potent anti-cancer agents

Betulinic acid is a natural compound with high in vitro cytotoxicity toward many cancer cells. However, the poor water solubility of this compound hampers an effective in vivo cancer study. We prepared new ionic derivatives of betulinic acid with higher water solubilities, without losing the structural integrity and functionality of this compound. As a result, these new ionic derivatives have shown much higher inhibitory effects against different cancer cell lines such as melanoma A375, neuroblastoma SH-SY5Y and breast adenocarcinoma MCF7. For A375 cell lines, the derivative 5 exhibited a low IC(50) value of 36 μM (vs 154 μM for betulinic acid); for MCF7 cell lines, the derivative 5 also exhibited a low IC(50) value of 25 μM (vs 112 μM for betulinic acid). The high cytotoxicity of these new derivatives can be linked to their greatly improved water solubility. Our assay method used little DMSO in aiding the dissolution of these derivatives to demonstrate the advantage of improved water solubility and to mimic the in vivo study conditions. The cell viability studies based on both MTT and LDH assay methods have confirmed the high inhibitory effect of our ionic derivatives of betulinic acid (particularly 4 and 5) against different cancer cells.

Isoform-specific inhibitors of ACATs: recent advances and promising developments

Acyl-CoA:cholesterol acyltransferase (ACAT) is a promising therapeutic target for cardiovascular diseases. Although a number of synthetic ACAT inhibitors have been developed, they have failed to show efficacy in clinical trials. Now, the presence of two ACAT isoforms with distinct functions, ACAT1 and ACAT2, has been discovered. Thus, the selectivity of ACAT inhibitors toward the two isoforms is important for their development as novel anti-atherosclerotic agents. The selectivity study indicated that fungal pyripyropene A (PPPA) is only an ACAT2-specific inhibitor. Furthermore, PPPA proved orally active in atherogenic mouse models, indicating it possessed cholesterol-lowering and atheroprotective activities. Certain PPPA derivatives, semi-synthetically prepared, possessed more potent and selective in vitro activity than PPPA against ACAT2. This review covers these studies and describes the future prospects of ACAT2-specific inhibitors.

Clinically useful anticancer, antitumor, and antiwrinkle agent, ursolic acid and related derivatives as medicinally important natural product

Medicinal plants are becoming an important research area for novel and bioactive molecules for drug discovery. Novel therapeutic strategies and agents are urgently needed to treat different incurable diseases. Many plant derived active compounds are in human clinical trials. Currently ursolic acid is in human clinical trial for treating cancer, tumor, and skin wrinkles. This review includes the clinical use of ursolic acid in various diseases including anticancer, antitumor, and antiwrinkle chemotherapies, and the isolation and purification of this tritepernoid from various plants to update current knowledge on the rapid analysis of ursolic acid by using analytical methods. In addition, the chemical modifications of ursolic acid to make more effective and water soluble derivatives, previous and current information regarding, its natural and semisynthetic analogs, focusing on its anticancer, cytotoxic, antitumor, antioxidant, anti-inflammatory, anti-HIV, acetyl cholinesterase, α-glucosidase, antimicrobial, and hepatoprotective activities, briefly discussion is attempted here for its research perspectives. This review article contains fourteen medicinally important ursolic acid derivatives and 351 references.

Triterpenoids isolated from Zizyphus jujuba inhibit foam cell formation in macrophages

Because foam cell formation in macrophages is believed to play an essential role in the progression of early atherosclerotic lesions in vivo, prevention of foam cell formation is considered to be one of the major targets for the treatment of atherosclerosis. The present study examined the inhibitory effect of 50 crude plant extracts on foam cell formation. Among those crude extracts, Zizyphi Fructus (ZF) and Zizyphi Semen (ZS) extracts significantly inhibited the foam cell formation induced by acetylated LDL. Furthermore, triterpenoids such as oleanonic acid, pomolic acid, and pomonic acid were the major active compounds, and triterpenoids containing a carboxylic acid at C-28 play an important role in the inhibitory effect on foam cell formation in human macrophages. These data suggest that triterpenoids in Zizyphus jujuba , the plant source of ZF and ZS, may therefore be useful for the prevention of atherosclerosis.

Triterpenic Acids Present in Hawthorn Lower Plasma Cholesterol by Inhibiting Intestinal ACAT Activity in Hamsters

Hawthorn (Crataegus pinnatifida) is an edible fruit used in traditional Chinese medicine to lower plasma lipids. This study explored lipid-lowering compounds and underlying mechanisms of action of hawthorn. Hawthorn powder extracts inhibited acylCoA:cholesterol acyltransferase (ACAT) activity in Caco-2 cells. The inhibitory activity was positively associated with triterpenic acid (i.e., oleanolic acid (OA) and ursolic acid (UA)) contents in the extracts. Cholesterol lowering effects of hawthorn and its potential additive effect in combination with plant sterol esters (PSE) were further studied in hamsters. Animals were fed a semi-synthetic diet containing 0.08% (w/w) cholesterol (control) or the same diet supplemented with (i) 0.37% hawthorn dichloromethane extract, (ii) 0.24% PSE, (iii) hawthorn dichloromethane extract (0.37%) plus PSE (0.24%) or (iv) OA/UA mixture (0.01%) for 4 weeks. Compared to the control diet, hawthorn, PSE, hawthorn plus PSE and OA/UA significantly lowered plasma non-HDL (VLDL + LDL) cholesterol concentrations by 8%, 9%, 21% and 6% and decreased hepatic cholesterol ester content by 9%, 23%, 46% and 22%, respectively. The cholesterol lowering effects of these ingredients were conversely associated with their capacities in increasing fecal neutral sterol excretion. In conclusion, OA and UA are responsible for the cholesterol lowering effect of hawthorn by inhibiting intestinal ACAT activity. In addition, hawthorn and particularly its bioactive compounds (OA and UA) enhanced the cholesterol lowering effect of plant sterols.

Betulinic acid, a natural compound with potent anticancer effects

New therapies using novel mechanisms to induce tumor cell death are needed with plants playing a crucial role as a source for potential anticancer compounds. One highly promising class of natural compounds are the triterpenoids with betulinic acid (BetA) as the most prominent representative. In-vitro studies have identified this agent as potently effective against a wide variety of cancer cells, also those derived from therapy-resistant and refractory tumors, whereas it has been found to be relatively nontoxic for healthy cells. In-vivo preclinically applied BetA showed some remarkable anticancer effects and a complete absence of systemic toxicity in rodents. BetA also cooperated with other therapies to induce tumor cell death and several potent derivatives have been discovered. Its antitumor activity has been related to its direct effects on mitochondria where it induces Bax/Bak-independent cytochrome-c release.

Hyaluronidase inhibitors from Takuran, Lycopus lucidus

Takuran is a traditional herbal medicine that is produced from the herbal plant Lycopus lucidas TURCZ. (Lamiaceae). Takuran is used as a treatment for diseases in women. From Takuran, four new phenylpropanoids along with 18 known compounds were isolated, and their structures were elucidated by spectroscopic analyses. Five phenylpropanoids isolated from the plant showed hyaluronidase inhibitory activity comparable to that of rosmarinic acid.

Protective role of betulinic acid on TNF-alpha-induced cell adhesion molecules in vascular endothelial cells

Vascular inflammation is an important event in the development of vascular diseases such as tumor progression and atherosclerosis. In the present study, betulinic acid (BA) treatment was found to show potent inhibitory effect on vascular inflammation process by TNF-alpha in human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with BA was blocked TNF-alpha induced expression level of cell adhesion molecules such as intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial cell selectin (E-selectin) as well as gelatinase in TNF-alpha-activated HUVEC in a dose-dependent manner. When preincubated with BA, the adhesion of HL-60 cells to TNF-alpha-induced HUVEC was significantly decreased in a concentration-dependent manner. TNF-alpha-induced intracellular ROS was markedly decreased by pretreatment with BA. Furthermore, BA significantly inhibited the translocation and transcriptional activity of NF-kappaB increased by TNF-alpha. In conclusion, these results suggested a vascular protective role of BA via inhibition of ROS and NF-kappaB activation in HUVEC.

Characterization of NVX-207, a novel betulinic acid-derived anti-cancer compound

BACKGROUND

Development of betulinic acid derivatives for clinical use has been hampered by adverse pharmacological and physico-chemical characteristics of this class of compounds. We here present a novel semi-synthetic betulinic acid-derived drug candidate well suited for further clinical development.

MATERIALS AND METHODS

In vitro activity and mode of action of NVX-207 were determined using normal as well as cancer cell lines. Gene expression profiling was performed with Affymetrix U133 microarrays. NVX-207 binding partners were identified using a heterobifunctional chemical crosslinker system. Potential binding proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Clinical studies were conducted in canine cancer patients suffering from spontaneously arising pre-treated tumours.

RESULTS

NVX-207 showed anti-tumour activity (mean IC(50) = 3.5 microM) against various human and canine cell lines. NVX-207-induced apoptosis was associated with activation of the intrinsic apoptotic pathway via cleavage of caspases -9, -3, -7 and of poly (ADP-ribose) polymerase (PARP). Global gene expression profiling demonstrated regulation of genes associated with lipid metabolism, most notably an upregulation of genes coding for insulin-induced gene 1 (Insig-1), low-density lipoprotein receptor (LDL-R) and of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA). NVX-207 bound to apolipoprotein A-I, a major regulator of lipid metabolism and cholesterol transport. A phase I/II study in dogs suffering from naturally occurring cancer receiving local treatment of NVX-207 (10 mg mL(-1)) showed excellent clinical responses including a complete remission in so far 5/5 treated animals.

CONCLUSIONS

NVX-207 is well tolerated and has significant anti-cancer activity in vitro and in vivo in dogs with treatment-resistant malignancies.

Antiatherogenic property of triterpenoids-enriched extract from the aerial parts of Salvia miltiorrhiza

This study investigated the antiatherogenic activity and the chemical constituents of a triterpenoids-enriched extract from the aerial parts of Salvia miltiorrhiza Bunge. The extract displayed a significant, dose-responsive antiatherogenic effect on LDLR(-/-) mice after a 24-week application in a daily dose 50, 100, 200, 1000 mg/kg, respectively. Pronounced systemic inflammation and cutaneous xanthomatosis inhibition effects of the extract, combined with hypocholesteremic and plaque stable properties, were shown in this study. At 200 mg/kg in the high dose treated group, the percent inhibitions of two inflammatory markers in serum, CRP and MCP-1, were 47.6 +/- 4.2% and 36.8 +/- 5.0%, and significant reductions in aortic atherosclerotic lesion areas were 62.3 +/- 3.9% (en face) and 77.8 +/- 3.1% (cross section) compared with the model group. No abnormal behavior or lethality were observed with the extract up to 1000 mg/kg. Fifteen triterpenoids were separated and identified from the extract. This study provided new evidence of the antiatherogenic property of S. miltiorrhiza correlated with triterpenoids by an antiinflammatory mechanism.

Oleanolic acid induces prostacyclin release in human vascular smooth muscle cells through a cyclooxygenase-2-dependent mechanism

Oleanolic acid is a triterpenoid that may contribute to the cardio-protective effects of olive oil. Our goal was to assess whether oleanolic acid could modulate eicosanoid biosynthesis and to determine the mechanism involved in this effect. Human coronary smooth muscle cells (SMC) were treated with oleanolic acid, erythrodiol, or hydroxytyrosol and eicosanoid release was measured by enzyme immunoassay. Cyclooxygenase (Cox)-1 and Cox-2 protein and messenger sRNA levels were analyzed by Western blot and real-time PCR, respectively. Mitogen-activated protein kinase (MAPK) pathways were assessed using specific antibodies. Oleanolic acid induced prostaglandin I2 (PGI2) release by human coronary SMC, an effect that was prevented by celecoxib (a specific inhibitor of Cox-2). The increased PGI2 was time-and dose-dependent and was associated to the up-regulation of Cox-2. No effects were observed on thromboxane A2. Erythrodiol but not hydroxytyrosol upregulated Cox-2 expression and induced PGI2 synthesis. Oleanolic acid induced an early phosphorylation of p38 MAPK and p42/44 MAPK but not c-Jun N-terminal kinase-1 (JNK-1). SB203580 (p38MAPK inhibitor) and U0126 (MAPK kinase1/2 inhibitor) abrogated the upregulation of Cox-2 and PGI2 release induced by oleanolic acid. A peptide inhibitor of JNK-1 (L-JNKI1) did not produce any effect. The induction of Cox-2 was preceded by an early activation of cAMP regulatory element-binding protein, a key transcription factor involved in Cox-2 transcriptional upregulation. Therefore, oleanolic acid contributes to vascular homeostasis by inducing PGI2 release in a Cox-2-dependent manner. Oleanolic acid could be regarded as a bioactive molecule that may contribute to the beneficial effects of the Mediterranean diet.

Ursane triterpenoids inhibit atherosclerosis and xanthoma in LDL receptor knockout mice

INTRODUCTION

In order to determine the mechanism of triterpenes, a class of secondary metabolites in plants, in modulating progression of vascular atherosclerotic lesions, we isolated three ursane triterpenoids (euscaphic acid, tormentic acid and 2alpha-hydroxyursolic acid) from aerial part of Salvia miltirrhiza Bge. and fed LDLr(-/-) mice the isolated compounds at a dose of 10 mg/kg p.o. for 24 weeks.

MATERIALS AND METHODS

The treated mice were raised with a cholesterol-enriched (1.25%) diet. Implying serum and aorta MCP-1 analysis, we found that all mice treated with the compounds exhibited a significant reduction of whole body and vascular inflammation.

RESULTS

The reduction of macrophage cells' number in aortic atherosclerotic lesions suggests that triterpenes treatment results in the development of a more stable plaque phenotype. Analysis of the structure-activity relationships demonstrates that compounds with a beta-orientated hydrogen-bond forming group at C-3 exhibit more potent anti-atherogenic effect than the alpha-counterpart on the development of atherosclerosis and xanthoma. However, the biological activities of the compounds are significantly reduced when they have C-19 hydrogen-bonds.

CONCLUSION

These Results suggest that down-regulation of MCP-1 is the main mechanism for antiatherogenic activity of triterpenes and MCP-1 might play important roles in the development of atherosclerosis and xanthoma.

Human acyl-CoA: cholesterol acyltransferase inhibitory activities of aliphatic acid amides from Zanthoxylum piperitum DC

Acyl-CoA: cholesterol acyltransferase (ACAT) plays an important role in the esterification of cholesterol with its substrates, cholesterol and fatty acyl coenzyme A, to facilitate both intracellular storage and intercellular transport. ACAT-1 is more involved in macrophage foam cell formation and ACAT-2 plays a critical role in the cholesterol absorption process in intestinal enterocytes. Three aliphatic acid amides, beta-sanshool (1), gamma-sanshool (2), and hydroxy-beta-sanshool (3), were isolated by bioassay-guided fractionation of the ethanolic extracts of Zanthoxylum piperitum DC. Compounds 1 and 2 inhibited human ACAT-1 and -2 activities with IC50 values of 39.0 and 79.7 microM for 1 and of 12.0 and 82.6 microM for 2, respectively. However, the hACAT-1 and -2 inhibitory activities of compound 3 having hydroxyl group were relatively less than those of compounds 1 and 2. A semi-synthetic compound 4, which has acetyl residue at 2'-OH of compound 3, exhibited the increased hACAT-1 and -2 inhibitory activities with IC50 values of 28.1 and 87.5 microM, respectively.

Effect of lupeol and lupeol linoleate on lipemic – hepatocellular aberrations in rats fed a high cholesterol diet

Cholesterol feeding has been often used to study the etiology of hypercholesterolaemia-related metabolic disturbances. The aim of the present study is to investigate the effects of a pentacyclic triterpene, lupeol, and its ester derivative on hepatic abnormalities associated with hypercholesterolemic rats. Hypercholesterolaemia was induced in male Wistar rats by feeding them with a high cholesterol diet (HCD) containing normal rat chow supplemented with 4% cholesterol and 1% cholic acid, for 30 days. Lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) during the last 15 days. Increased hepatic lipid profile along with abnormalities in lipid-metabolizing enzyme activities were seen in hypercholesterolemic rats. An apparent increase in the expression of Acyl-CoA cholesterol acyltransferase mRNA was seen in HCD fed rats. The activities of hepatic marker enzymes, which serve as indices of cellular injury, were altered in HCD fed rats. Treatment with triterpenes significantly modulated the abnormalities induced by hypercholesterolaemia. Also, an increased (P >0.001) faecal excretion of cholesterol and bile acids were observed in lupeol and lupeol linoleate group when compared with HCD fed group. Therefore, it can be concluded that triterpenes treatment afforded substantial protection against the anomalies, which are manifested during the early stage of hypercholesterolemic atherogenesis.

Birch bark research and development

This review will detail progress made in the previous decade on the chemistry and bioactivity of birch bark extractive products. Current and future applications of birch bark natural products in pharmaceuticals, cosmetics, and dietary supplements for the prevention and treatment of cancer, HIV,and other human pathogens are reviewed. Current developments in the technology of birch bark processing are discussed. New approaches for the synthesis of potentially valuable birch bark triterpenoid derivatives are also reviewed.