Triterpenoids from the Flower of Campsis grandiflora K. Schum. as Human Acyl-CoA: Cholesterol Acyltransferase Inhibitors

Iridoids and other constituents from the leaves and stems of Valeriana officinalis var. latifolia

Fifty-nine compounds, including nineteen previously undescribed iridoids (valeriananols A-S) and an undescribed alkaloid (5'-isovaleryl uridine), were isolated from the leaves and stems of Valeriana officinalis var. latifolia. Their structures were elucidated based on Mass spectrometry and NMR spectroscopy. The absolute configuration of valeriananols A-C, E-N, P, Q and S was determined by experimental and calculated electronic circular dichroism. Structurally, valeriananols A and B were two 1,3-seco-iridoids with a 3,6-epoxy moiety, valeriananols K and L were a pair of C-4 epimers, while valeriananol S was a 4'-deoxy iridoid glycoside. In addition, valeriananol P, stenopterin A and patriscabioin C exhibited significant inhibition on nitric oxide production with IC50 values of 10.31, 3.93 and 8.69 μM, respectively. Furthermore, stenopterin A and patriscabioin C showed anti-proliferation activity on the MCF-7 cell line with IC50 values of 17.28 and 13.89 μM, respectively.

Anti-osteoporosis effects of triterpenoids from the fruit of sea buckthorn (Hippophae rhamnoides) through the promotion of osteoblast differentiation in mesenchymal stem cells, C3H10T1/2

In a previous study, we discovered that the ethanolic extract of sea buckthorn (Hippophae rhamnoides) fruits exhibited anti-osteoporosis effects both in vitro and in vivo. Through bioassay-guided fractionation, we identified the hexane fraction (HRH) as the active fraction, which was further fractionated using preparative HPLC. Among the resulting six fractions, HRHF4 showed significant activity. In the present study, we focused on the bioassay-guided isolation of bioactive compounds from the HRHF4 fraction. We successfully identified the active HRHF43 fraction, which led us to the isolation of potential bioactive compounds (1-6). The chemical structures of these compounds were determined using NMR data, LC-MS analysis, and HR-ESI-MS data as four triterpenes, ursolic acid (1), uvaol (2), oleanolic aldehyde (3), and ursolic aldehyde (4), together with two fatty acids, methyl linoleate (5) and ethyl oleate (6). To evaluate the efficacy of promoting osteoblast differentiation and the expression of mRNA biomarkers related to osteogenesis, we tested the isolated compounds in the mouse mesenchymal stem cell line, C3H10T1/2. Alkaline phosphate staining demonstrated that triterpenes (1-4) displayed osteogenic activity. Particularly noteworthy, ursolic aldehyde (4) exhibited the most potent effect, showing an 11.2-fold higher activity at a concentration of 10 μg/mL compared to the negative control. Moreover, ursolic aldehyde (4) upregulated the gene expression of bone formation-related biomarkers, including Runx2, Osterix, Alp, and Osteopontin. These findings suggest that the fruit extract of H. rhamnoides may have potential as a nutraceutical for promoting bone health, with ursolic aldehyde (4) identified as an active constituent.

In Vitro and In Silico Anti-Picornavirus Triterpene Alkanoic Acid Ester from Saudi Collection of Rhazya stricta Decne

The total alcohol extract obtained from the aerial parts of R. stricta and fractions of the liquid-liquid fractionation process were tested against picornavirus-causing foot-and-mouth disease (FMD) based on the traditional use of the plant in Saudi Arabia. The most active petroleum ether soluble fraction was subjected to chromatographic purification, and nine compounds were isolated, identified using various chemical and spectroscopic methods, and tested for their anti-viral potential. The new ester identified as α-Amyrin 3-(3'R-hydroxy)-hexadecanoate (1) was the most active compound with 51% inhibition of the viral growth and was given the name Rhazyin A. Compounds with ursane skeleton were more active than those with lupane skeleton except in the case of the acid derivatives where betulenic acid showed 26.1% inhibition against the viral growth, while ursolic acid showed only 16.6% inhibition. Moreover, molecular docking analysis using a glide extra-precision module was utilized for investigating the possible molecular interactions accounting for anti-viral activity against picornavirus of the nine isolated compounds. Molecular docking studies revealed a strong binding of the discovered hits within the active site of FMDV 3C^pro. Compound 1 showed the lowest docking score within the nine isolated compounds comparable to the two known anti-viral drugs; glycyrrhizic acid and ribavirin. The results of this research will provide lead candidates from natural origin with potential safety and efficacy compared to the synthetic ones with lower production costs for managing FMVD.

Design, synthesis, and biological evaluation of new arjunolic acid derivatives as anticancer agents

Arjunolic acid (AA) is a pentacyclic triterpenoid with promising anticancer properties. A series of novel AA derivatives containing a pentameric A-ring with an enal moiety, combined with additional modifications at C-28, were designed and prepared. The biological activity on the viability of human cancer and non-tumor cell lines was evaluated in order to identify the most promising derivatives. Additionally, a preliminary study of the structure-activity relationship was carried out. The most active derivative, derivative 26, also showed the best selectivity between malignant cells and non-malignant fibroblasts. For compound 26, the anticancer molecular mechanism of action in PANC-1 cells was further studied and the results showed that this derivative induced a cell-cycle arrest at G0/G1 phase and significantly inhibited the wound closure rate of PANC-1 cancer cells in a concentration-dependent manner. Additionally, compound 26 synergistically increased the cytotoxicity of Gemcitabine, especially at a concentration of 0.24 μM. Moreover, a preliminary pharmacological study indicated that at lower doses this compound did not demonstrate toxicity in vivo. Taken together, these findings suggest that compound 26 may be a valuable compound for the development of new pancreatic anticancer treatment, and further studies are needed to explore its full potential.

Predicting the potential distribution of Campsis grandiflora in China under climate change

Because the research on the geographical distribution of species significantly influences people's understanding of species protection and utilization, it is important to study the influence of climate change on plants' geographical distribution patterns. Based on 166 distribution records and 11 climate and terrain variables, we used MaxEnt (Maximum Entropy) model and ArcGIS software to predict the potential distribution of Campsis grandiflora under climate change and then determined the dominant climate variables that significantly affected its geographical distribution. In our study, the area under the curve (AUC) value of the training data was 0.939, proving the accuracy of our prediction. Under current climate conditions, the area of potentially suitable habitat is 238.29 × 10⁴ km², mainly distributed in northern, central, southern, and eastern China. The dominant variables that affect the geographical distribution of C. grandiflora are temperature, precipitation and altitude. In the future climate change scenario, the total area of suitable habitat and highly suitable habitat will increase, whereas the area of moderately suitable habitat and poorly suitable habitat will decrease. In addition, the centroid of the potentially suitable area of C. grandiflora will migrate to higher latitude and higher altitudes areas. The results could give strategic guidance for development, protection, and utilization of C. grandiflora in China.

Sorbus intermedia (EHRH.) PERS. fruits as a novel source of biologically active triterpenoids - Comparative studies of ursolic acid derivatives with cytotoxic potential

In the current study, the fruits of a popular ornamental tree, Sorbus intermedia, were investigated phytochemically and biologically as potential source of bioactive triterpenes. Six terpenoids were isolated and examined with respect to their cytotoxic activity using a broad screening in vitro model and multivariate analysis for better demonstration of the effects on cancer cells. This chemometric approach allowed us to confirm that the structural characteristics of the compounds significantly affected their impact on cell lines. Ursolic acid was found to be the most potent cytotoxic agent with IC₅₀ predominantly < 10 μg/mL after 24 h of incubation. Its 3-acetoxy derivative was less active, however, an improvement in selectivity with regard to prostate panel was observed. Reduction of the carboxylic moiety at C28, as well as introduction of the hydroxyl group at 19α position led to complete loss of cytotoxic activity.

In vitro evaluation of the involvement of Nrf2 in maslinic acid-mediated anti-inflammatory effects in atheroma pathogenesis

AIMS

Maslinic acid (MA) is a naturally occurring pentacyclic triterpene known to exert cardioprotective effects. This study aims to investigate the involvement of nuclear factor erythroid 2-related factor 2 (Nrf2) for MA-mediated anti-inflammatory effects in atheroma pathogenesis in vitro, including evaluation of tumor necrosis factor-alpha (TNF-α)-induced monocyte recruitment, oxidized low-density lipoprotein (oxLDL)-induced scavenger receptors expression, and nuclear factor-kappa B (NF-ĸB) activity in human umbilical vein endothelial cells (HUVECS) and human acute monocytic leukemia cell line (THP-1) macrophages.

MATERIALS AND METHODS

An in vitro monocyte recruitment model utilizing THP-1 and HUVECs was developed to evaluate TNF-α-induced monocyte adhesion and trans-endothelial migration. To study the role of Nrf2 for MA-mediated anti-inflammatory effects, Nrf2 inhibitor ML385 was used as the pharmacological inhibitor. The expression of Nrf2, monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1), cluster of differentiation 36 (CD36), and scavenger receptor type A (SR-A) in HUVECs and THP-1 macrophages were investigated using RT-qPCR and Western blotting. The NF-κB activity was determined using NF-κB (p65) Transcription Factor Assay Kit.

KEY FINDINGS

The results showed opposing effects of MA on Nrf2 expression in HUVECs and THP-1 macrophages. MA suppressed TNF-α-induced Nrf2 expression in HUVECs, but enhanced its expression in THP-1 macrophages. Combined effects of MA and ML385 suppressed MCP-1, VCAM-1, and SR-A expressions. Intriguingly, at the protein level, ML385 selectively inhibited SR-A but enhanced CD36 expression. Meanwhile, ML385 further enhanced MA-mediated inhibition of NF-κB activity in HUVECs. This effect, however, was not observed in THP-1 macrophages.

SIGNIFICANCE

MA attenuated foam cell formation by suppressing VCAM-1, MCP-1, and SR-A expression, as well as NF-κB activity, possibly through Nrf2 inhibition. The involvement of Nrf2 for MA-mediated anti-inflammatory effects however differs between HUVECs and macrophages. Future investigations are warranted for a detailed evaluation of the contributing roles of Nrf2 in foam cells formation.

Increased Stress Resistance and Lifespan in Chaenorhabditis elegans Wildtype and Knockout Mutants-Implications for Depression Treatment by Medicinal Herbs

Depression and anxiety disorders are widespread diseases, and they belong to the leading causes of disability and greatest burdens on healthcare systems worldwide. It is expected that the numbers will dramatically rise during the COVID-19 pandemic. Established medications are not sufficient to adequately treat depression and are not available for everyone. Plants from traditional medicine may be promising alternatives to treat depressive symptoms. The model organism Chaenorhabditis elegans was used to assess the stress reducing effects of methanol/dichlormethane extracts from plants used in traditional medicine. After initial screening for antioxidant activity, nine extracts were selected for in vivo testing in oxidative stress, heat stress, and osmotic stress assays. Additionally, anti-aging properties were evaluated in lifespan assay. The extracts from Acanthopanax senticosus, Campsis grandiflora, Centella asiatica, Corydalis yanhusuo, Dan Zhi, Houttuynia cordata, Psoralea corylifolia, Valeriana officinalis, and Withaniasomnifera showed antioxidant activity of more than 15 Trolox equivalents per mg extract. The extracts significantly lowered ROS in mutants, increased resistance to heat stress and osmotic stress, and the extended lifespan of the nematodes. The plant extracts tested showed promising results in increasing stress resistance in the nematode model. Further analyses are needed, in order to unravel underlying mechanisms and transfer results to humans.

Natural pentacyclic triterpenoid acids potentially useful as biocompatible nanocarriers

The importance of natural raw materials has grown recently because of their ready availability, renewable nature, biocompatibility and controllable degradability. One such group of plant-derived substances includes the triterpenoid acids, terpenic compounds consisting of six isoprene units, a carboxyl group and other functional groups producing various isomers. Most can be easily extracted from different parts of the plant and modified successfully. By themselves or as aglycones (genins) of triterpene saponins, they have potentially useful pharmaceutical activity. This review focuses on the supramolecular properties of triterpenoid acids with regard to their subsequent use as biocompatible nanocarriers. The review also considers the current list of pentacyclic triterpene acids for which molecular self-assembly has been confirmed without the need for structural modification.

Pentacyclic triterpenes with nitric oxide inhibitory activity from Potentilla chinensis

Three new ursane-type triterpenes (1-3) and twenty-one known triterpenoids (4-24) were isolated from the methanolic extract of the whole plants of Potentilla chinensis. Their structures were elucidated by extensive spectroscopic analysis of 1D and 2D NMR (HSQC, HMBC, COSY and ROESY) and HRESIMS data. The bioassay screening revealed the inhibitory effects on nitric oxide production of compounds 2, 5, 7, 9, 10, and 13-24 in LPS-induced RAW264.7 macrophages.

Biological effects of corosolic acid as an anti-inflammatory, anti-metabolic syndrome and anti-neoplasic natural compound

Accumulating evidence has indicated that corosolic acid exerts anti-diabetic, anti-obesity, anti-inflammatory, anti-hyperlipidemic and anti-viral effects. More importantly, corosolic acid has recently attracted much attention due to its anticancer properties and innocuous effects on normal cells. Furthermore, the increasing proportion of obese and/or diabetic populations has led to an epidemic of non-alcoholic fatty liver disease (NAFLD), which frequently progresses to hepatocellular carcinoma (HCC). Evidence has indicated that NAFLD is closely associated with the development of HCC and comprises a high risk factor. The present review summarizes the anticancer effects of corosolic acid in vitro and in vivo, and its related molecular mechanisms. It also describes the inhibitory effects of corosolic acid on the progression of NAFLD and its associated molecular mechanisms, providing guidance for future research on corosolic acid in NAFLD-related HCC prevention and treatment. To the best of our knowledge, a review of corosolic acid as an anticancer agent has not yet been reported. Due to its multitargeted activity in cancer cells, corosolic acid exerts anticancer effects when administered alone, and acts synergistically when administered with chemotherapeutic drugs, even in drug-resistant cells. In addition, as a novel tool to treat metabolic syndromes, corosolic acid uses the same mechanism in its action against cancer as that used in the progression of NAFLD-related HCC. Therefore, corosolic acid has been suggested as an agent for the prevention and treatment of NAFLD-related HCC.

Self assembled arjunolic acid acts as a smart weapon against cancer through TNF- α mediated ROS generation

Arjunolic acid (AA) a plant derived pentacyclic triterpenoid which showed effective anticancer activity against MCF-7 and HeLa cells as well as no significant toxic effect was observed against normal lymphocytes. In the current study the self assemble property of arjunolic acid gives an extra emphasis on anticancer activity which was proved by several fluorescence studies like ROS generation, EtBr/AO and DAPI staining. At a selected dose of 50μg/ml AA disrupt the redox balance inside the cancer cells by producing reactive oxygen species. The apoptotic event was mediated by two key regulator proteins TNF-α and NF-κß which was proved here. The increment of the pro-inflammatory cytokines indicates the ROS mediated pathway of cancer cell apoptosis.

Identification and Quantitation of Ursolic and Oleanolic Acids in Ilex aquifolium L. Leaf Extracts Using 13C and 1H-NMR Spectroscopy

Leaves of Ilex aquifolium L. have been used for their therapeutic properties. In previous studies, components contained in the leaves were first isolated by various chromatographic techniques. Then, quantitation of oleanolic and ursolic acids, which are responsible for the biological and therapeutic activities of the plant, was performed by HPLC, HPTLC, and somewhat by GC-MS. Our objective was to develop a simple method that allows the identification of compounds contained in the leaves of Corsican I. aquifolium and to quantify ursolic and oleanolic acids. Leaves were successively extracted with hexane and dichloromethane. The extracts were chromatographed on silica gel and the fractions of column chromatography submitted to 13C-NMR analysis, following a computerized method developed in the laboratory. 13C-NMR allowed the identification of various triterpenes including ursolic acid and oleanolic acid. Quantitation of both acids was achieved, for the first time, by 1H-NMR after validation of the method (accuracy, precision, linearity, limit of detection and limit of quantitation). Ursolic and oleanolic acids accounted for 55.3% and 20.8% of the dichloromethane extract, respectively. This represents 1.3% and 0.5% of the mass of dried leaves. 1H-NMR spectroscopy appeared as a powerful tool for a rapid quantitation of biologically active compounds from I. aquifolium.

Triterpenes from the fruit of Camptotheca acuminata suppress human hepatocellular carcinoma cell proliferation through apoptosis induction

The fruit of Camptotheca acuminata, a kind of mainly medicinal plant, possesses good antitumor properties. In order to explore the bioactive compounds for the treatment of hepatocellular carcinoma, the study focused on the isolation of cytotoxic compounds from the fruit of Camptotheca acuminata, which led to the discovery of fourteen compounds, including one new triterpene, 3β,20-dihydroxy-30α-methyl,17(29)-β-epoxy-28-norlupane (1), together with thirteen known compounds (2-14). The structures of isolated compounds were demonstrated by spectroscopic methods including 1D and 2D NMR spectroscopy. Moreover, all triterpenes were evaluated for antiproliferative activities against two human hepatocellular carcinoma cell lines, HepG2 and Hep3B. Compound 3 showed the strongest cytotoxic activity against the HepG2 with IC₅₀ value at 29.6 μM. Further study demonstrated that compound 3 exhibited cytotoxic activity through the induction of apoptosis.

Identification of Novel Melanin Synthesis Inhibitors From Crataegus pycnoloba Using an in Vivo Zebrafish Phenotypic Assay

Zebrafish has emerged as a powerful model organism for high throughput drug screening. Several morphological criteria, transgenic lines and in situ expression screens have been developed to identify novel bioactive compounds and their mechanism of action. Here, we used the inhibition of melanogenesis during early zebrafish embryo development to identify natural compounds that block melanogenesis. We identified an extract from the Greek hawthorn Crataegus pycnoloba as a potent inhibitor of melanin synthesis and used activity based subfractionation to identify active subfractions and eventually three single compounds of the same family (dibenzofurans). These compounds show reversible inhibition of melanin synthesis and do not act via inhibition of tyrosinase. We also showed that they do not interfere with neural crest differentiation or migration. We identified via in silico modeling that the compounds can bind to the aryl hydrocarbon receptor (AHR) and verified activation of the Ahr signaling pathway showing the induction of the expression of target genes.

Antihyperlipidaemic effect of triterpenic acid-enriched fraction from Cyclocarya paliurus leaves in hyperlipidaemic rats

CONTEXT

Cyclocarya paliurus (Batal) Iljinskaja (Juglandaceae) is an edible and medicinal plant; the leaves are used in Chinese folkloric medicine to treat dyslipidaemia and diabetes.

OBJECTIVE

This study evaluates the antihyperlipidaemic potential of the triterpenic acid-enriched fraction (TAE) from C. paliurus and the underlying mechanism.

MATERIALS AND METHODS

The hyperlipidaemic rats were induced by high fat diet for 6 weeks. After oral administration of TAE (200 and 400 mg/kg), the neutral fraction (150 and 300 mg/kg) and statin (4 mg/kg) to the hyperlipidaemic rats for 4 weeks, lipid profile and apolipoprotein (apoB48) level in plasma, and the expression levels of apoB48, microsomal triglyceride transfer protein (MTP), phosphorylation of mitogen-activated protein kinase (MAPK) and tumour necrosis factor α (TNF-α) in intestine were examined. The main constituents in the TAE were identified by HPLC-MS.

RESULTS

TAE administration (400 mg/kg) decreased the levels of atherogenic lipids in serum and liver (p < 0.05) and increased serum high-density lipoprotein cholesterol by 19.7%. Furthermore, TAE treatment (200 and 400 mg/kg) decreased plasma apoB48 level by 15.3 and 19.5%, downregulated intestinal apoB48 and MTP expression levels (p < 0.05), and inhibited TNF-α expression by 36.2 and 56.2% and the phosphorylation level of MAPK by 8.8 and 13.2%, respectively. HPLC analysis revealed the presence of pentacyclic- and tetracyclic-triterpene acids in TAE.

CONCLUSION AND DISCUSSION

These findings suggested that TAE possessed antihyperlipidaemic activity partially involved in the inhibitory effect on apoB48 overproduction, which may provide evidence about its potential role in ameliorating dyslipidaemia.

Triterpenoids from Cyclocarya paliurus and their inhibitory effect on the secretion of apoliprotein B48 in Caco-2 cells

Five previously undescribed compounds including two triterpenoid aglycones, 3β,23-dihydroxy-1,12-dioxo-olean-28-oic acid and 3β,23,27-trihydroxy-1-oxo-olean-12-ene-28-oic acid, and three triterpenoid glucosides cyclocarioside L-N, along with 17 known compounds were isolated from a CH₃Cl-soluble extract of the leaves of Cyclocarya paliurus. Two 27-nor-triterpenoid glycosides were isolated from the genus for the first time. Furthermore, the characterized compounds were tested for the inhibitory effects on apoliprotein B48 secretion in Caco-2 cells. Seven triterpenoid aglycones together with four triterpenoid saponins significantly decreased the apoliprotein B48 oversecretion induced by oleic acid in Caco-2 cells.

Hypolipidemic effect of oleanolic acid is mediated by the miR-98-5p/PGC-1β axis in high-fat diet-induced hyperlipidemic mice

Oleanolic acid (OA) is an active component of the traditional Chinese herb Olea europaea L. and has been found to exhibit a significant lipid-lowering effect; however, its direct molecular target is still unknown, which limits its clinical application and the possible structure modification to improve its beneficial functions. In this regard, we carried out the present study to identify potential hepatic targets of OA to mediate its lipid-lowering effect. We found that both acute and chronic OA treatments reduced serum levels of triglycerides, total cholesterol, and LDL cholesterol, and decreased hepatic expression levels of peroxisome proliferator-activated receptor-γ coactivator-1β (PGC-1β), which is an important regulator in maintaining hepatic lipid homeostasis, and its downstream target genes. Of note, liver-specific knockdown of PGC-1β recapitulated the hypolipidemic effects of OA. At the molecular level, OA accelerated mRNA degradation of PGC-1β. Microarray analysis revealed a host of microRNAs that potentially mediate OA-induced PGC-1β mRNA degradation, among which, miR-98-5p significantly inhibited activity of Pgc-1β 3' UTR as well as PGC-1β expression and promoted its mRNA degradation. Conversely, miR-98-5p inhibitors blunted the inhibitory effects of OA on PGC-1β expression. Collectively, our data demonstrated that OA ameliorated hyperlipidemia, likely via regulation of the miR-98-5p/PGC-1β axis.-Chen, S., Wen, X., Zhang, W., Wang, C., Liu, J., Liu, C. Hypolipidemic effect of oleanolic acid is mediated by the miR-98-5p/PGC-1β axis in high-fat diet-induced hyperlipidemic mice.

Cholesterol-lowering effects and potential mechanisms of different polar extracts from Cyclocarya paliurus leave in hyperlipidemic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cyclocarya paliurus Batal., native only to China, is widely consumed as a Chinese traditional folk medicine for the prevention and treatment of hyperlipidemia, obesity, and diabetes. The aim of the study is to investigate the cholesterol-lowering effect and potential mechanisms of different polar extracts from Cyclocarya paliurus leaves in mice fed with high-fat-diet.

MATERIALS AND METHODS

Cyclocarya paliurus leaves extracts were orally administered to diet-induced hyperlipidemic mice for 4 weeks. Simvastatin was used as a positive control. Body weight, food intake, histopathology of liver and adipose tissues, hepatic and renal function indices, lipid profiles in the serum and liver were evaluated. Total bile acid concentrations of the liver and feces were also measured. Furthermore, the activities and mRNA expression of cholesterol metabolism-related enzymes including 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase (CYP7A1) and acyl-CoA cholesterol acyltransferase 2 (ACAT2) in the livers of the mice were analyzed. LC-MS detection was performed to identify the components in the active fraction of Cyclocarya paliurus extracts.

RESULTS

Different Cyclocarya paliurus polar extracts, especially ChE reduced the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and hepatic TC and TG, enhanced the level of serum high-density lipoprotein cholesterol (HDL-C), restored hepatic and renal function indices and histomorphology. HMG-CoA reductase activity and mRNA expression were decreased, while CYP7A1 activity and mRNA expression as well as the level of fecal and hepatic bile acid were increased by ChE. LC-MS analysis of ChE revealed the presence of six main triterpenoids, which might be responsible for its antihyperlipidemic bioactivity.

CONCLUSIONS

Evidently ChE possesses the best antihyperlipidemic activity, and the cholesterol-lowering effect is at least partly attributed to its role in promoting the conversion of cholesterol into bile acids by upgrading the activity and mRNA expression of CYP7A1 and inhibiting those of HMG-CoA reductase to lower the cholesterol biosynthesis.

Mechanistic Perspectives of Maslinic Acid in Targeting Inflammation

Chronic inflammation drives the development of various pathological diseases such as rheumatoid arthritis, atherosclerosis, multiple sclerosis, and cancer. The arachidonic acid pathway represents one of the major mechanisms for inflammation. Prostaglandins (PGs) are lipid products generated from arachidonic acid by the action of cyclooxygenase (COX) enzymes and their activity is blocked by nonsteroidal anti-inflammatory drugs (NSAIDS). The use of natural compounds in regulation of COX activity/prostaglandins production is receiving increasing attention. In Mediterranean diet, olive oil and table olives contain significant dietary sources of maslinic acid. Maslinic acid is arising as a safe and novel natural pentacyclic triterpene which has protective effects against chronic inflammatory diseases in various in vivo and in vitro experimental models. Understanding the anti-inflammatory mechanism of maslinic acid is crucial for its development as a potential dietary nutraceutical. This review focuses on the mechanistic action of maslinic acid in regulating the inflammation pathways through modulation of the arachidonic acid metabolism including the nuclear factor-kappa B (NF-κB)/COX-2 expression, upstream protein kinase signaling, and phospholipase A₂ enzyme activity. Further investigations may provide insight into the mechanism of maslinic acid in regulating the molecular targets and their associated pathways in response to specific inflammatory stimuli.

Antidepressant-like and anti-oxidative efficacy of Campsis grandiflora flower

OBJECTIVES

Our study aimed to investigate the antidepressant-like effect of ethyl acetate extract of the flowers of Campsis grandiflora (EFCG) in a mice model of chronic unpredictable mild stress (CUMS).

METHODS

HPLC-Q-TOF-MS was used to identify the chemical constituents of EFCG. The DPPH assay and ABTS radical-scavenging assay were performed to measure the antioxidant properties. The protective properties of EFCG against H2 O2 -induced oxidative damage were analysed in PC12 cells. The changes of behaviour profiles were investigated by using open-field test, sucrose preference test, forced swimming test (FST) and tail suspension test (TST). Brain tissue samples of mice were collected, and antioxidative measure levels were measured.

KEY FINDINGS

The result showed that EFCG had the most active anti-oxidative effect and the protective effect against H2 O2 oxidative injury in PC12 cells. Treatment with the EFCG significantly reduced the depressant-like severity and immobility period as compared with untreated CUMS mice in FST and TST. Moreover, EFCG significantly elevated the contents of superoxide dismutase, Glutathione Peroxidase and decreased the contents of Malonaldehyde (MDA) in mice brain.

CONCLUSIONS

Our study found first the antidepressant activity of the EFCG. The results suggested the therapeutic potential of EFCG for depressive disorder.

Maslinic acid, a natural phytoalexin-type triterpene from olives--a promising nutraceutical?

Maslinic acid is a pentacyclic triterpene found in a variety of natural sources, ranging from herbal remedies used in traditional Asian medicine to edible vegetables and fruits present in the Mediterranean diet. In recent years, several studies have proved that maslinic acid exerts a wide range of biological activities, i.e. antitumor, antidiabetic, antioxidant, cardioprotective, neuroprotective, antiparasitic and growth-stimulating. Experimental models used for the assessment of maslinic acid effects include established cell lines, which have been often used to elucidate the underlying mechanisms of action, and also animal models of different disorders, which have confirmed the effects of the triterpene in vivo. Overall, and supported by the lack of adverse effects in mice, the results provide evidence of the potential of maslinic acid as a nutraceutical, not only for health promotion, but also as a therapeutic adjuvant in the treatment of several disorders.

C-4 gem-dimethylated oleanes of Gymnema sylvestre and their pharmacological activities

Gymnema sylvestre R. Br., one of the most important medicinal plants of the Asclepiadaceae family, is a herb distributed throughout the World, predominantly in tropical countries. The plant, widely used for the treatment of diabetes and as a diuretic in Indian proprietary medicines, possesses beneficial digestive, anti-inflammatory, hypoglycemic and anti-helmentic effects. Furthermore, it is believed to be useful in the treatment of dyspepsia, constipation, jaundice, hemorrhoids, cardiopathy, asthma, bronchitis and leucoderma. A literature survey revealed that some other notable pharmacological activities of the plant such as anti-obesity, hypolipidemic, antimicrobial, free radical scavenging and anti-inflammatory properties have been proven too. This paper aims to summarize the chemical and pharmacological reports on a large group of C-4 gem-dimethylated pentacyclic triterpenoids from Gymnema sylvestre.

Arjunolic acid: a new multifunctional therapeutic promise of alternative medicine

IMPORTANCE OF THE FIELD

In recent years, a number of studies describing the effective therapeutic strategies of medicinal plants and their active constituents in traditional medicine have been reported. Indeed, tremendous demand for the development and implementation of these plant derived biomolecules in complementary and alternative medicine is increasing and appear to be promising candidates for pharmaceutical industrial research. These new molecules, especially those from natural resources, are considered as potential therapeutic targets, because they are derived from commonly consumed foodstuff and are considered to be safe for humans.

AREAS COVERED IN THIS REVIEW

This review highlights the beneficial role of arjunolic acid, a naturally occurring chiral triterpenoid saponin, in various organ pathophysiology and the underlying mechanism of its protective action. Studies on the biochemistry and pharmacology suggest the potential use of arjunolic acid as a novel promising therapeutic strategy.

WHAT THE READERS WILL GAIN

The multifunctional therapeutic application of arjunolic acid has already been documented by its various biological functions including antioxidant, anti-fungal, anti-bacterial, anticholinesterase, antitumor, antiasthmatic, wound healing and insect growth inhibitor activities. The scientific basis behind its therapeutic application as a cardioprotective agent in traditional medicine is justified by its ability to prevent myocardial necrosis and apoptosis, platelet aggregation, coagulation and lowering of blood pressure, heart rate, as well as cholesterol levels. Its antioxidant property coupled with metal chelating property (by its two hydroxyl groups) protects different organs from metal and drug-induced organ pathophysiology. Arjunolic acid also plays a beneficial role in the pathogenesis of diabetes and its associated complications. The mechanism of cytoprotection of arjunolic acid, at least in part, results from the detoxification of reactive oxygen species (ROS) produced in the respective pathophysiology. In addition to its other biological functions, it also possesses vibrant insecticidal properties and it has the potential to be used as a structural molecular framework for the design of molecular receptors in the general area of supramolecular chemistry and nanochemistry. Esters of arjunolic acid function as organogelators which has wide application in designing thermochromic switches and sensor devices. Arjunolic acid derived crown ether is an attractive candidate for the design of molecular receptors, biomimetics and supramolecular systems capable of performing some biological functions.

HOME MESSAGE

This review would provide useful information about the recent progress of natural product research in the domain of clinical science. This review also aims to untie the multifunctional therapeutic application of arjunolic acid, a nanometer-long naturally occurring chiral triterpenoid biomolecule.

Isolation and quantitation of ecologically important phloroglucinols and other compounds from Eucalyptus jensenii

INTRODUCTION

Eucalyptus jensenii has not been explored for its phytoconstituents except for its essential oil although a formylated phloroglucinol compound jensenone has been the focus of several ecological studies.

OBJECTIVE

i) To optimise the extraction conditions for preparative scale isolation of jensenone and other secondary metabolites from leaves. (ii) To develop an RP-HPLC method for simultaneous determination of phloroglucinols and other compounds in Eucalyptus leaves.

METHODOLOGY

Jensenone and other compounds were isolated from acetone extract using VLC over TLC grade silica. HPLC quantitation of isolated compounds was undertaken on a C₁₈-column using acetonitrile-water (2% formic acid) gradient elution.

RESULTS

Extraction conditions for isolation of jensenone were optimised and more than 99% pure jensenone was obtained in a yield of 2.1% from the dried leaves. Ten phloroglucinol compounds, including a new nuclear methylated phloroglucinol named 4-O-demethyl miniatone, and two triterpenoids were also isolated. A RP-HPLC method was developed for simultaneous quantitation of phloroglucinols and other compounds in different extracts of E. jensenii leaves. A total of 19 compounds reported from different species of Eucalyptus was separated by this method.

CONCLUSION

The method described for isolation of jensenone is a simple, rapid and low-cost procedure amenable to the preparative scale. A new monomeric phloroglucinol compound was isolated and characterised from the acetone extract of E. jensenii leaves. The HPLC method developed can be applied successfully to different eucalypt matrices for precise and accurate determination of 19 secondary metabolites belonging to different chemical classes.

Arjunolic acid: beneficial role in type 1 diabetes and its associated organ pathophysiology

In this review article, we describe the most recent development of the beneficial effect of arjunolic acid (AA) in reducing type 1 diabetic pathophysiology. Diabetic mellitus is a serious and growing health problem worldwide. Increasing evidence suggest that oxidative stress plays a pivotal role in the pathogenesis of diabetes and its associated complications. Use of antioxidant supplements as a complimentary therapeutic approach in diabetes has, therefore, been seriously considered worldwide. AA, a natural pentacyclic triterpenoid saponin, is well known for various biological functions including antioxidant activity. It could prevent the increased production of ROS, RNS, AGEs, and the 8OHdG/2dG ratio and increase the intracellular antioxidant defence system. Signal transduction studies showed that AA could prevent hyperglycaemia induced activation of MAPKs, PKC, NF-κB signalling cascades and apoptotic cell death. Combining, AA supplements could be regarded as beneficial therapeutics in the treatment of diabetes and its associated complications.

Bignoniaceae metabolites as semiochemicals

Members of the family Bignoniaceae are mostly found in tropical and neo-tropical regions in America, Asia and Africa, although some of them are cultivated in other regions as ornamentals. Species belonging to this family have been extensively studied in regard to their pharmacological properties (as extracts and isolated compounds). The aim of this review is to summarize the reported scientific evidence about the chemical properties as well as that of the extracts and isolated compounds from species of this family, focusing mainly in insect-plant interactions. As it is known, this family is recognized for the presence of iridoids which are markers of oviposition and feeding preference to species which have became specialist feeders. Some herbivore species have also evolved to the point of been able to sequester iridoids and use them as defenses against their predators. However, iridoids also exhibit anti-insect properties, and therefore they may be good lead molecules to develop botanical pesticides. Other secondary metabolites, such as quinones, and whole extracts have also shown potential as anti-insect agents.

Dietary corosolic acid ameliorates obesity and hepatic steatosis in KK-Ay mice

Corosolic acid (CRA), a constituent of Banaba leaves, has been reported to exert anti-hypertension, anti-hyperinsulinemia, anti-hyperglycemia, and anti-hyperlipidemia effects as well as to induce anti-inflammatory and anti-oxidative activities. The aim of this study was to investigate the inhibitory effects of CRA on the development of obesity and hepatic steatosis in KK-Ay mice, a genetically obese mouse model. Six-week-old KK-Ay mice were fed a high fat diet for 9 weeks with or without 0.023% CRA. Nine-week CRA treatment resulted in 10% lower body weight and 15% lower total fat (visceral plus subcutaneous fat) mass than in control mice. CRA treatment reduced fasting plasma levels of glucose, insulin, and triglyceride by 23%, 41%, and 22%, respectively. The improved insulin sensitivity in CRA-treated mice may be due on part to the increased plasma adiponectin and white adipose tissue (WAT) AdipoR1 levels. In addition, CRA treatment increased the expression of peroxisome proliferator-activated receptor (PPAR) alpha in liver and PPAR gamma in WAT. This is the first study to show that CRA treatment can contribute to reduced body weight and amelioration of hepatic steatosis in mice fed a high fat diet, due in part to increased expression of PPAR alpha in liver and PPAR gamma in WAT.

Effect of corosolic acid on gluconeogenesis in rat liver

Corosolic acid (CRA), an active component of Banaba leaves (Lagerstroemia speciosa L.), decreases blood glucose in diabetic animals and humans. In this study, we investigated the mechanism of action of CRA on gluconeogenesis in rat liver. CRA (20-100 microM) dose-dependently decreased gluconeogenesis in perfused liver and in isolated hepatocytes. Fructose-2,6-bisphosphate (F-2,6-BP), a gluconeogenic intermediate, plays a critical role in hepatic glucose output by regulating gluconeogenesis and glycolysis in the liver. CRA increased the production of F-2,6-BP along with a decrease in intracellular levels of cAMP both in the presence and in the absence of forskolin in isolated hepatocytes. While a cAMP-dependent protein kinase (PKA) inhibitor inhibited hepatic gluconeogenesis, the drug did not intensify the inhibitory effect of CRA on hepatic gluconeogenesis in isolated hepatocytes. These results indicate that CRA inhibits gluconeogenesis by increasing the production of F-2,6-BP by lowering the cAMP level and inhibiting PKA activity in isolated hepatocytes. Furthermore, CRA increased glucokinase activity in isolated hepatocytes without affecting glucose-6-phosphatase activity, suggesting the promotion of glycolysis. These effects on hepatic glucose metabolism may underlie the various anti-diabetic actions of CRA.

Insulin-mimetic and insulin-sensitizing activities of a pentacyclic triterpenoid insulin receptor activator

Five pentacyclic triterpenoids isolated from Campsis grandiflora were tested for insulin-mimetic and insulin-sensitizing activity. The compounds enhanced the activity of insulin on tyrosine phosphorylation of the IR (insulin receptor) beta-subunit in CHO/IR (Chinese-hamster ovary cells expressing human IR). Among the compounds tested, CG7 (ursolic acid) showed the greatest enhancement and CG11 (myrianthic acid) the least. We characterized the effect of CG7 further, and showed that it acted as an effective insulin-mimetic agent at doses above 50 mug/ml and as an insulin-sensitizer at doses as low as 1 mug/ml. Additional experiments showed that CG7 increased the number of IRs that were activated by insulin. This indicates that a major mechanism by which CG7 enhances total IR auto-phosphorylation is by promoting the tyrosine phosphorylation of additional IRs. CG7 not only potentiated insulin-mediated signalling (tyrosine phosphorylation of the IR beta-subunit, phosphorylation of Akt and glycogen synthase kinase-3beta), but also enhanced the effect of insulin on translocation of glucose transporter 4 in a classical insulin-sensitive cell line, 3T3-L1 adipocytes. The results of the present study demonstrate that a specific pentacyclic triterpenoid, CG7, exerts an insulin-sensitizing effect as an IR activator in CHO/IR cells and adipocytes. The enhancement of insulin activity by CG7 may be useful for developing a new class of specific IR activators for treatment of Type 1 and Type 2 diabetes.

Corosolic acid prevents oxidative stress, inflammation and hypertension in SHR/NDmcr-cp rats, a model of metabolic syndrome

Corosolic acid (CRA), a constituent of banaba leaves, has been reported to have anti-inflammatory and hypoglycemic activities. The aim of this study was to determine the effects of CRA on metabolic risk factors including obesity, hypertension, hyperinsulinemia, hyperglycemia, and hyperlipidemia together with oxidative stress and inflammation, all of which are characteristic of the SHR/NDmcr-cp (cp/cp) (SHR-cp) rat, an animal model of metabolic syndrome. Six-week-old male SHR-cp rats were fed a high fat diet containing 0.072% CRA for 14 weeks. Treatment with CRA lowered blood pressure, which was elevated in control animals, by 10% after 8 weeks, and serum free fatty acids by 21% after 2 weeks. CRA treatment resulted in decreases in the levels of the oxidative stress markers thiobarbituric acid-reactive substances and 8-hydroxydeoxyguanosine by 27% and 59%, respectively, after 2 weeks. CRA treatment also reduced the levels of myeloperoxidase markers, 3-nitrotyrosine and 3-chlorotyrosine by 38% and 39%, respectively, after 10 weeks, and tended to decrease the levels of high sensitivity C-reactive protein, a marker of inflammation, after 6 weeks. However, CRA had no effect on weight gain or hyperglycemia. These results demonstrate that CRA can ameliorate hypertension, abnormal lipid metabolism, and oxidative stress as well as the inflammatory state in SHR-cp rats. This implies that CRA can be beneficial for preventing atherosclerosis-related diseases that are an increasing health care problem worldwide.