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A new clerodane diterpene, 2β-methoxyhardwickiic acid (1), and four known compounds (2–5) were isolated from the twigs of Monoon membranifolium. The structure of the new compound was determined by extensive spectroscopic methods and ESITOFMS data. The absolute configuration of 1 was established by a comparison of its ECD spectrum and specific rotation with those of related previously reported compounds. All compounds were evaluated for their nitric oxide (NO) production inhibitory activities in RAW264.7 macrophage cells. Compounds 3 and 5 inhibited NO production with IC50 values of 16.1 and 28.9 μM, respectively, which were better than that of standard compound, indomethacin (IC50 = 32.2 μM).

The rise of antibiotic resistance presents a significant healthcare challenge and precludes the use of many otherwise valuable antibiotics. One potential solution to this problem is the use of anti...

Salvia semiatrata Zucc. (Lamiaceae) is a species used as a tranquilizer and to relieve pain in folk medicine in Santiago Huauclilla, Oaxaca, Mexico. To evaluate the antinociceptive and anxiolytic-like effects of S. semiatrata extracts and identify a bioactive metabolite. The extracts were obtained by maceration of S. semiatrata aerial parts using solvents in increasing polarity (hexane, ethyl acetate and methanol). A neo-clerodane diterpene was extracted from the ethyl acetate fraction using open column chromatography. Identification of this metabolite was performed by crystallography, 1H NMR, 13C NMR, ATR-IR, ECD, MS and elemental analysis. The antinociceptive activity was explored using the writhing and formalin tests. Whereas, the anxiolytic-like responses were analysed in the open-field, hole-board and plus-maze tests. All the treatments were administered using oral gavage in male CD1 mice and explored 30 min after administration of the individual extracts (300 mg/kg) or the compound 1 (0.1, 1 or 10 mg/kg). All the extracts produced significant reduction in the nociceptive and anxiety-like behaviour compared to mice treated with the vehicle (0.5% tween 80 in saline solution). The spectroscopic analysis corroborated the presence of the neo-clerodane diterpene 7-keto-neoclerodan-3,13-dien-18,19:15,16-diolide (1), as partial responsible of the antinociceptive and anxiolytic-like effects, which produced a dose-dependent response in the writhing test with an ED50=4.15 mg/kg. Discussion and conclusions: These results reinforce the medicinal properties of S. semiatrata in folk medicine, where participation of a neo-clerodane diterpene was evidenced in the inhibitory central nervous system activity of this species.

A clerodane diterpene compound 16-hydroxycleroda-3,13-dien-15,16-olide (CD) is considered a therapeutic agent with pharmacological activities. The present study investigated the mechanisms of CD-induced apoptosis in T24 human bladder cancer cells. CD inhibited cell proliferation in a concentration and time-dependent manner. CD-induced overproduction of reactive oxygen species and reduced mitochondrial membrane potential, associated with reduced expression of Bcl-2 and increased levels of cytosolic cytochrome c, cleaved PARP-1 and caspase-3. In addition, CD treatment led to cell cycle arrest at the G0/G1 phase and inhibited expression of cyclin D1 and cyclin-dependent kinases 2 and 4 and led to increased levels of p21, p27Kip1 and p53. All of these events were accompanied with a reduction of pEGFR, pMEK1/2, pERK1/2, pAkt, pmTOR, pP70S6K1, HIF-1&alpha, c-Myc and VEGF. RNAseq-based analysis revealed that CD-induced cell death was characterised by an increased expression of stress and apoptotic-related genes as well as inhibition of the cell cycle-related genes. In summary, CD induces apoptosis in T24 bladder cancer cells through targeting multiple intracellular signaling pathways as a result of oxidative stress and cell cycle arrest.

Made available in DSpace on 2022-04-29T08:45:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Casearin X (CAS X) is the major clerodane diterpene isolated from the leaves of Casearia sylvestris and has been extensively studied due to its powerful cytotoxic activity at low concentrations. Promising results for in vivo antitumor action have also been described when CAS X was administered intraperitoneally in mice. Conversely, loss of activity was observed when orally administered. Since the advancement of natural products as drug candidates requires satisfactory bioavailability for their pharmacological effect, this work aimed to characterize the CAS X metabolism by employing an in vitro microsomal model for the prediction of preclinical pharmacokinetic data. Rat and human liver microsomes were used to assess species differences. A high-performance liquid chromatography with diode-array detection (HPLC-DAD) method for the quantification of CAS X in microsomes was developed and validated according to European Medicines Agency guidelines. CAS X was demonstrated to be a substrate for carboxylesterases via hydrolysis reaction, with a Michaelis-Menten kinetic profile. The enzyme kinetic parameters were determined, and the intrinsic clearance was 1.7-fold higher in humans than in rats. The hepatic clearance was estimated by in vitro - in vivo extrapolation, resulting in more than 90% of the hepatic blood flow for both species. A qualitative study was also carried out for the metabolite identification by mass spectrometry and indicated the formation of the inactive metabolite CAS X dialdehyde. These findings demonstrate that CAS X is susceptible to first-pass metabolism and is a substrate for specific carboxylesterases expressed in liver, which may contribute to a reduction in antitumor activity when administered by the oral route. Núcleo de Pesquisa em Produtos Naturais e Sintéticos (NPPNS) Departamento de Física e Química Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo Departamento de Química Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Universidade de São Paulo, Avenida Bandeirantes 3900 Núcleo de Bioensaios Biossíntese e Ecofisiologia de Produtos Naturais (NuBBE) Departamento de Química Orgânica Instituto de Química Universidade Do Estado de São Paulo Departamento de Química Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Universidade de São Paulo

Yu-Chi Chen,1 Bu-Miin Huang,2 Wei-Chang Lee,3 Yung-Chia Chen3,4 1Department of Urology, E-Da Hospital, Kaohsiung, Taiwan; 2Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan; 3Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 4Department of Anatomy, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Background: Clerodane diterpene, 16-hydroxycleroda-3,13-dien-15,16-olide (CD) isolated from Polyalthia longifolia Benth. & Hook. f. var. pendula was found to be a potential apoptotic inducer in human leukemia, lung cancer, and colon cancer cells. However, the molecular mechanism remains elusive in renal system. Thus, in the present study, the regulatory mechanisms of CD-induced apoptosis in clear cell renal cell carcinoma (ccRCC) cells were investigated. Materials and methods: Cell proliferation was evaluated by colony formation assay and cell cycle analyses. Protein expressions of focal adhesion (FA) related complexes were examined by immunofluorescence staining and Western blot analyses. Cell migration and invasion capabilities of renal cell carcinoma (RCC) cells were determined by wound healing and Transwell assays. Results: CD inhibited cell colony formations, induced cell arrest at G2/M phase, and increased subG1 cell population both in 786-O and A-498. During CD treatment, the “rounded-up” cells were observed. The immune-staining of phosphorylated focal adhesion kinase (pFAK), vinculin, and paxillin displayed disassembly of the FA. Moreover, disruption of actin stress fibers was noted after CD treatment. Consistent with the findings, the expressions of pSrc, pFAK, FAK, vinculin, vimentin, and paxillin were all downregulated by CD. In addition, CD attenuated cell migration and invasion activities accompanied by the reductions of pNF-κB, matrix metalloproteinase (MMP)-2, MMP-9 as well as vascular endothelial growth factor expressions. Conclusion: CD induced cell cycle arrest, FA complex disassembly, and the inactivation of migratory-related signaling pathways to induce apoptosis in ccRCC cells. Keywords: focal adhesion, signaling pathway, Polyalthia longifolia, clerodane diterpene, migration, invasion, renal cell carcinoma, RCC

Background Dodonaea angustifolia is used in Ethiopian traditional medicine to treat malaria. The objective of this work was to conduct bioassay guided fractionation of the leaves of D. angustifolia using Plasmodium berghei infected mice. Method The antiplasmodial activity of the extracts and pure compounds was evaluated using the standard Peter's four-day suppressive method. The structures of isolated compounds were elucidated using chemi-cal and spectroscopic methods. Results In this study, the ethyl acetate soluble portion of the 80% aqueous MeOH extract of the leaves significantly suppressed parasitaemia in Plasmodium berghei infected mice (80.28% at 150 mg/kg). Three active compounds which exhibited significant percent suppression of parasitaemia by 81% at 40 mg/kg, 80% at 50 mg/kg and 70% at 40 mg/kg, respectively were identified. These are the flavanone pinocembrin (1), the flavanol santin (2) and the clerodane diterpene 2-hydroxy-15,16-epoxyceloda-3,13(16),14-trien-18-oic acid (3). Under similar conditions, chloroquine suppressed parasitaemia by 100% at 25 mg/kg. Chemical study of the ethanol extract of the leaves yielded 5,7,4'-trihydroxy-3,6-dimethoxyflavone (4), ent-16-hydroxy-labdan-3α,8β-dihydroxy,13(14)-en-15,16-olide (5) and 5,6,7-trihydroxy-3,4'-dimethoxyflavone (6). Compound 6 has not been reported before as a natural product. Conclusion From the leaves of D. angustifolia, three compounds with significant antiplasmodial activi-ties were isolated and characterized, with pinocembrin as the most active compound.

Systematic analyses of plants that are used in traditional medicine may lead to the discovery of novel cytotoxic secondary metabolites. Diterpene possesses multiple bioactivities; here, epoxy clerodane diterpene (ECD) was isolated from Tinospora cordifolia (Willd.) stem and shown potential antiproliferative effect in MCF-7 human breast cancer cells. The antiproliferative effect of ECD on MCF-7 cells was systematically analyzed by cell and nuclear morphology, alterations in oxidative stress, and the expression of tumor suppressor and mitochondria-mediated apoptosis-related genes. We found that the IC50 value of ECD was 3.2μM at 24h and 2.4μM at 48h. We observed that the cytotoxicity of ECD was specific to MCF-7 cells, whereas ECD was nontoxic to normal Vero and V79 cells. ECD significantly triggered intracellular ROS generation even from the lower doses of 0.6 and 1.2μM; and it is relative to higher dose of 2.4μM. Further, we used 0.6μM, 1.2μM and 2.4μM as experimental doses to analyze the relative dose-dependent effects. Nuclear staining revealed that cells treated with the 2.4μM dose exhibited characteristic apoptotic morphological changes and that 46% of the cells were apoptotic and 4% were necrotic after 48h. ECD significantly increased the expression of mitochondria-dependent apoptotic pathway-related genes after 48h; we observed significantly (p≤0.05) increased expression of CYP1A, GPX, GSK3β and TNF-α and downregulated expression of NF-κB. ECD also increased the expression of tumor suppressor genes such as Cdkn2A, Rb1 and p53. In addition, we observed that ECD treatment significantly (p≤0.001) upregulated the expression of apoptotic genes such as Bax, cas-3, cas-8, cas-9 and p21 and downregulated the expression of BCL-2, mdm2 and PCNA. In conclusion, ECD regulates the expression of Cdkn2A, p53 and mdm2 and induces apoptosis via the mitochondrial pathway in MCF-7 human breast cancer cells.

The discovery of potent cytotoxic isolates from botanicals provides an opportunity to explore this viable tool for cancer chemoprevention. The antileukemic potential of clerodane diterpene from Polyalthia longifolia leaves has already been established. However, in this present study, utilizing chromatographic techniques we report for the first time, the isolation of a rare tetranorditerpene (compound 1) from P. longifolia. The structure of compound 1 was elucidated and confirmed by spectrophotometric data. UPLC-MS analysis was conducted on the methanolic extract, ethyl acetate fraction, and isolated tetranorditerpene showed that the tetranorditerpene is one of the major constituents of the plant with a retention time of 30.78 min. In addition, a methyl ester derivative (compound 2) of the isolated tetranorditerpene was synthesized. Using the CCK-8 assay, we compared the cytotoxic potential of isolated tetranorditerpene (1) and methyl ester derivative (2) with the previously isolated clerodane diterpenes. Our results showed that the methyl ester derivative (2) displayed the highest inhibitory activity against human leukemia HL-60 cells. The isolated tetranorditerpene (1) did not exhibit significant inhibitory effect against HL-60 cells. Morphological examination indicated chromatin condensation and nuclear fragmentation suggesting induction of apoptosis in compound 2 treated HL-60 cells. The methyl esterification of the isolated tetranorditerpene (1) conferred on it a significant level of antileukemic activity suggesting the possibility of a synergistic relationship between pure compound isolation and synthetic reaction in the discovery of new chemopreventive agents.

Made available in DSpace on 2019-10-06T16:34:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Clerodane diterpenes from Casearia sylvestris are antiulcerogenic and anti-inflammatory. The finding that they may undergo acid degradation or hepatic metabolization led to an investigation of their degradation products. Purified clerodane diterpenes (casearins J and O) were subjected to in vitro assays to simulate their oral administration. Resulting derivatives were identified using chromatographic and spectrometric techniques. Nitric oxide synthesis by LPS-stimulated macrophages was assayed to verify whether structural modifications alter the anti-inflammatory activity of diterpenes. Nine compounds (1–9) were identified after acid degradation remaining 5.05% of casearin J. Besides the remaining casearin O (13.1%), eight compounds (10–17) were identified. The dialdehydes from each casearin were the major constituents. S9 rat liver treatment of casearins J and O generated two compounds identical to some of those produced by acid degradation, which remained 36.8% and 36.5% intact, respectively. Both casearins and its derivatives were not cytotoxicity at concentrations lower than 0.312 μg/mL (0.555 μM for casearin J and 0.516 μM for casearin O) and did not inhibit the nitric oxide production in this concentration. Thus, the structural modifications conducted did not alter the activity of casearins and the anti-inflammatory pathway of diterpenes probably is not involved on nitric oxide modulation. São Paulo State University (Unesp) School of Pharmaceutical Sciences Department of Natural Principles and Toxicology University of São Paulo (USP) Faculty of Philosophy Sciences and Letters Department of Chemistry São Paulo State University (Unesp) School of Pharmaceutical Sciences Department of Biological Sciences University of Araraquara Department of Health and Biological Sciences São Paulo State University (Unesp) School of Pharmaceutical Sciences Department of Natural Principles and Toxicology São Paulo State University (Unesp) School of Pharmaceutical Sciences Department of Biological Sciences

Serine protease dipeptidyl peptidase 4 (DPP-4) is involved in self/non-self-recognition and insulin sensitivity. DPP-4 inhibitors are conventional choices for diabetic treatment, however, side effects such as headache, bronchus infection, and nasopharyngitis might affect the daily lives of diabetic patients. Notably, natural compounds are believed to have a similar efficacy with lower adverse effects. This study aimed to validate the DPP-4 inhibitory activity of clerodane diterpene 16-hydroxycleroda-3,13-dien-15,16-olide (HCD) from Polyalthia longifolia, rutin, quercetin, and berberine, previously selected through molecular docking. The inhibitory potency of natural DPP-4 candidates was further determined by enzymatic, in vitro Caco-2, and ERK/PKA activation in myocyte and pancreatic cells. The hypoglycemic efficacy of the natural compounds was consecutively analyzed by single-dose and multiple-dose administration in diet-induced obese diabetic mice. All the natural-compounds could directly inhibit DPP-4 activity in enzymatic assay and Caco-2 inhibition assay, and HCD showed the highest inhibition of the compounds. HCD down-regulated LPS-induced ERK phosphorylation in myocyte but blocked GLP-1 induced PKA expression. For in vivo tests, HCD showed hypoglycemic efficacy only in single-dose administration. After 28-days administration, HCD exhibited hypolipidemic and hepatoprotective efficacy. These results revealed that HCD performed potential antidiabetic activity via inhibition of single-dose and long-term administrations, and could be a new prospective anti-diabetic drug candidate.

The phytochemical study of Uruguayan specimens of Allophylus edulis (Sapindaceae) yielded the isolation of various natural products being some of them reported for the first time in this species. Although most of them are ubiquitous in the plant kingdom, some revealed in this study to have anti insect properties. Two sesquiterpenes (6,7-Epoxicaryophyllene and spathulenol), two phytosterols (sitosterone and sitosterol), a pentacyclic triterpene (lupeol) and a clerodane diterpene were isolated. 6,7-Epoxycaryophyllene, lupeol and sitosterol showed to be deterrent against the aphid Myzus persicae and the coleopteran Epilachna paenulata. Moreover, the crude ethanolic extract of twigs of A. edulis showed to be deterrent against both insect species being some of its fractions also active against another aphid, Rhopalosiphum padi. Various active compounds against different insect models have been isolated from the twigs extract of A. edulis. The results evidenced synergic as well as antagonistic effects in the mixture, summed to differential activity against the insects, a desirable attribute when developing botanical pesticides.

Two new neo-clerodane diterpenoids, teucvisins A and B (1, 2), and three new 19-nor-neoclerodane diterpenoids, teucvisins C-E (3-5), together with ten known constituents (6-15) were isolated from the whole plants of Teucrium viscidum. All the isolates were evaluated for their inhibitory activities of lipopolysaccharide (LPS)-induced nitric oxide production in RAW264.7 macrophages. The results indicated that compounds 11 and 15 showed moderate inhibition with an IC50 value of 21.9 and 22.4 µM, respectively.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:28:34Z No. of bitstreams: 0 Made available in DSpace on 2014-05-27T11:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-03-01 Studies have shown that Casearia sylvestris compounds protect DNA from damage both in vitro and in vivo. Complementarily, the aim of the present study was to assess the chemopreventive effect of casearin B (CASB) against DNA damage using the Ames test, the comet assay and the DCFDA antioxidant assay. The genotoxicity was assessed by the comet assay in HepG2 cells. CASB was genotoxic at concentrations higher than 0.30μM when incubated with the FPG (formamidopyrimidine-DNA glycosylase) enzyme. For the antigenotoxicity comet assay, CASB protected the DNA from damage caused by H2O2 in the HepG2 cell line in concentrations above 0.04μM with post-treatment, and above 0.08μM with pre-treatment. CASB was not mutagenic (Ames test) in TA 98 and TA 102. In the antimutagenicity assays, the compound was a strong inhibitor against aflatoxin B1 (AFB) in TA 98 (>88.8%), whereas it was moderate (42.7-59.4%) inhibitor against mytomicin C (MMC) in TA 102. Additionally, in the antioxidant assay using DCFDA, CASB reduced reactive oxygen species (ROS) generated by H2O2. In conclusion, CASB was genotoxic to HepG2 cells at high concentrations; was protective of DNA at low concentrations, as shown by the Ames test and comet assay; and was also antioxidant. © 2012 Elsevier Ltd. UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Clinical Analysis, Rua Expedicionários do Brasil 1621, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Natural Principles and Toxicology, Rodovia Araraquara-Jaú km 01, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Biological Sciences, Rodovia Araraquara-Jaú km 1, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara Chemistry Institute, Rua Prof. Francisco Degni, s/n, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Clinical Analysis, Rua Expedicionários do Brasil 1621, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Natural Principles and Toxicology, Rodovia Araraquara-Jaú km 01, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara School of Pharmaceutical Sciences Department of Biological Sciences, Rodovia Araraquara-Jaú km 1, Araraquara, SP UNESP - Univ. Estadual Paulista, Araraquara Chemistry Institute, Rua Prof. Francisco Degni, s/n, Araraquara, SP

Polyalthia is a versatile genus of shrubs and trees found in tropic and sub-tropic regions. In this study, three clerodane diterpenes, kolavenic acid (1), polyalthialdoic acid (2), and 16α-hydroxy-cleroda-3,13(14)Z-dien-15,16-olide (3) isolated from Polyalthia longifolia leaves were evaluated for their apoptotic potential against human leukemia HL-60 cells. Compounds 2 and 3 inhibited cell proliferation with IC₅₀ values of 21.8 and 13.7 μM, respectively. Morphological changes and DNA fragmentation analysis indicated that these diterpenes induce apoptotic cell death in the HL-60 cells. Our results revealed the importance of P. longifolia as a chemopreventive medicinal plant.

Background: Tinospora crispa (L.) is used to alleviate the symptoms of diabetes mellitus in folk medicine. It is also used for hypertension and to treat malaria, remedy for diarrhea, and as vermifuge. Materials and Methods: Stems of T. crispa were collected, sun dried for several days followed by oven dried for 24 h at a considerably low temperature and then ground into coarse powder. The powdered stems were soaked in methanol at room temperature for 14 days with occasional shaking. The extract was collected by filtration, and the solvent was evaporated under reduced pressure in a rotary evaporator to obtain a solid residue which was then subjected to fractionation using the modified Kupchan partitioning method into n-hexane, CCl4, CHCl3 and aqueous soluble fractions. The n-hexane soluble fraction was chromatographed over sephadex (LH-20) and the column was eluted with n-hexane: CH2Cl2:MeOH (2:5:1) followed by CH2Cl2:MeOH (9:1) and MeOH (100%) in order to increase the polarities. The column fractions were then concentrated and subjected to thin layer chromatography screening and the fractions with a satisfactory resolution of compounds were rechromatographed over silica gel to isolate the pure compounds. Results: Four new furanoid diterpenes of clerodane types, Crispene A, B, C, and D (1–4), including one known furanoid diterpene glucoside, borapetoside E (5), were isolated from the stems of T. crispa. The structures of these compounds were elucidated by means of extensive spectroscopic analysis and by comparison of their spectral data with closely related compounds. Conclusion: We have reported four new furanoid diterpenes of clerodane types, including one known furanoid diterpene glucoside. This is the first report of any clerodane diterpene having olefinic bond between C-6 and C-7. SUMMARY Crispene A, B, C, and D, four new furanoid diterpenes of clerodane types from Tinospora crispaCrispene C, an unusual furanoid diterpene with olifinic bond between C-6 and C-7First report of Crispene D as a free aglycone, though it was earlier reported as an enzymatic hydrolysis product. Abbreviation used: TLC: Thin layer chromatography, NMR: Nuclear magnetic resonance, COSY: Correlation spectroscopy, NOE: Nuclear overhauser effect, HPLC: High-performance liquid chromatography, ESI-MS: Electrospray ionization mass spectroscopy

The clerodane diterpene casearin X (1), isolated from the leaves of Casearia sylvestris, is a potential new drug candidate due to its potent in vitro cytotoxic activity. In this work, the intestinal absorption mechanism of 1 was evaluated using Caco-2 cells with and without active carboxylesterases (CES). An LC-MS method was developed and validated for the quantification of 1. The estimation of permeability coefficients was possible only under CES-inhibited conditions in which 1 is able to cross the Caco-2 cell monolayer. The mechanism is probably by active transport, with no significant efflux, but with a high retention of the compound inside the cells. The enzymatic hydrolysis assay demonstrates the susceptibility of 1 to first-pass metabolism as substrate for specific CES expressed in human intestine.

A new clerodane-type diterpenoid, echinoclerodane A (1), was isolated from a Formosan gorgonian coral Echinomuricea sp. The structure of 1 was elucidated by spectroscopic methods. Echinoclerodane A (1) is the first clerodane-type compound obtained from the marine organisms belonging to the phylum Cnidaria. Echinoclerodane A (1) exhibited moderate cytotoxicity toward MOLT-4, HL-60, DLD-1 and LoVo tumor cells and inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils.

Ethnopharmacological relevance Baccharis trimera (Less.) DC. (Asteraceae) is a species native to South America used in Brazilian folk medicine to treat gastrointestinal and liver diseases, kidney disorders and diabetes. Previous studies from this laboratory confirmed the antacid and antiulcer activities of the plant aqueous extract (AE) in rat and mouse models. Aim of the study To investigate the mechanisms involved in the antacid action of AE and isolated compounds from Baccharis trimera. Materials and methods AE was assayed in vivo in cold-restraint stress gastric ulcers and in pylorus-ligated mice. Nine fractions (F2–F10) previously isolated from AE were assayed in vitro on acid secretion measured as [ 14 C]-aminopyrine ([ 14 C]-AP) accumulation in rabbit gastric glands, and on gastric microsomal H + , K + -ATPase preparations. Chlorogenic acids (F2, F3, F6, F7), flavonoids (F9), an ent -clerodane diterpene (F8) and a dilactonic neo -clerodane diterpene (F10) have been identified in these fractions. Results Intraduodenal injection of AE (1.0 and 2.0 g/kg) in 4 h pylorus-ligated mice decreased the volume (20 and 50%) and total acidity (34 and 50%) of acid secretion compared to control values. Administered orally at the same doses AE protected against gastric mucosal lesions induced in mice by restraint at 4 °C. Exposure of isolated rabbit gastric glands to fractions F8 (10–100 μM) and F9 (10–300 μg/ml) decreased the basal [ 14 C]-AP uptake by 50 and 60% of control (Ratio = 6.2 ± 1.1), whereas the remaining fractions were inactive. In the presence of the secretagogues F2 and F4 (30–300 μg/ml) decreased the [ 14 C]-AP uptake induced by histamine (His) with a 100-fold lower potency than that of ranitidine. F5 and F6 reduced the [ 14 C]-AP uptake stimulated by carbachol (CCh), but they were 10 to 20-fold less potent than atropine. F8 (diterpene 2 ) and F9 (flavonoids) decreased both the His- and CCh-induced [ 14 C]-AP uptake, whereas F10 (diterpene 1 ) was inactive against the [ 14 C]-AP uptake stimulated by secretagogues. Diterpene 2 was the most active of all tested compounds being 7-fold less potent than ranitidine and equipotent to atropine in reducing acid secretion in vitro . This compound also reduced the gastric H + , K + -ATPase activity by 20% of control, while the remaining fractions were inactive on the proton pump in vitro . Conclusions The results indicate that Baccharis trimera presents constituents that inhibit gastric acid secretion by acting mainly on the cholinergic regulatory pathway. The plant extract also contains compounds that exert moderate inhibition of the histaminergic regulatory pathway of acid secretion and the gastric proton pump. Altogether these active constituents appear to provide effective inhibition of acid secretion in vivo , which may explain the reputed antiulcer activity of the plant extract.

A clerodane diterpene (plaunol A) and three flavonoids (vitexin; luteolin-7-O-β-D-glucoside and luteolin-4'-O-glucoside) were isolated from stems and leaves of Croton stellatoliosus Ohba, using series of chromatographic techniques. Evaluation for anti-inflammatory activity in LPS-induced RAW264.7 cells revealed that, only plaunol A exhibited the inhibitory activity on nitric oxide production with the IC50 of 11.69 μM. This was no cytotoxic effect to the cells at a concentration of 100 μM, by MTT assay. Determination of mRNA levels by qRT-PCR, indicated that plaunol A suppressed the expressions of inducible nitric oxide synthase and cyclooxygenase-2 in lipopolysaccharide-induced RAW264.7 cells.

Two new clerodane diterpenes 4 and 3, along with four known constituents, including neocleroda- 3,13-diene-15,16-olide-18-oic acid (1), stictic acid (2), hautriwaic acid (5), and 15,16-epoxy-19- hydroxy-1,3,13(16),14-clerodatetraen-18-oic acid (6), were isolated from stems and leaves of Dodonaea viscosa. Their structures were elucidated by spectroscopic methods, including one- and twodimensional NMR experiments (COSY, HMBC, HMQC, and ROESY)

About 20 species from Callicarpa have reported ethnobotanical and ethnomedical uses, and several members of this genus are well known in the traditional medical systems of China and South Asia. Ethnomedical reports indicate their use in the treatment of hepatitis, rheumatism, fever, headache, indigestion, and other ailments. Several species of Callicarpa have been reported to be used against cancer (e.g., Callicarpa americana root to treat skin cancer and Callicarpa rubella bark to treat tumors of the large intestine). Extracts from about 14 species in this genus have been evaluated for biological activity, including antibacterial, antifungal, anti-insect growth, cytotoxic, and phytotoxic activities. In addition to amino acids, benzenoids, simple carbohydrates, and lipids, numerous diterpenes, flavonoids, phenylpropanoids, phytosterols, sesquiterpenes, and triterpenes have been detected in or isolated from the genus Callicarpa. The essential oils of Callicarpa americana have recently been reported to have antialgal and phytotoxic activities, and several isolates from this species (and C. japonica) were identified as contributing to the mosquito bite-deterrent activity that was first indicated by folkloric usage. Recent bioassay-guided investigations of C. americana extracts have resulted in the isolation of several active compounds, mainly of the clerodane diterpene structural type.

Staphylococcus aureus infections are raising serious concern across the world. The effectiveness of conventional drugs is continuously decreasing due to global emergence of multidrug resistance (MDR) and therefore, new resistance-modifying agents (RMAs) are highly needed.Clerodane diterpene 16α-hydroxycleroda-3,13(14)-Z-dien-15,16-olide (CD) from leaves of Polyalthia longifolia (Sonn.) Thwaites (Annonaceae) as RAM will be useful in improving the current treatment strategies for staphylococcal infections.In the present study, we determine the resistance-modifying activity of CD using clinical isolates of MRSA. Further, the influence of CD on innate immune response was also evaluated in vitro and in vivo. The nature of potential interactions was determined by fractional inhibitory concentration indices (FICIs) calculated from microdilution assays and time-kill curves.The result of in vitro combination study showed that CD significantly reduced MIC of fluoroquinolones up to 16-folds (FICI 0.315-0.500), while in S. aureus infected Swiss albino mice model, combination of CD with norfloxacin, significantly (p0.01, p0.001) lowered the systemic microbial burden in blood, liver, kidney, lung and spleen tissues in comparison to CD, norfloxacin alone as well as untreated control. Flow cytometry analysis clearly showed that CD significantly inhibited EtBr efflux and extended post-antibiotic effect. In qRT-PCR analysis, CD alone as well as in combination, significantly modulated the expression of various efflux pump genes including norA up to 2-fold in clinical isolate MRSA-ST2071. Further, the in vitro combination study of the CD (10, 5, 2.5µg/ml) along with the norfloxacin (10µg/ml) depicted a significant decline in the pro-inflammatory cytokines, IL6 and TNF-α. In septic shock mice model, CD did not exhibit any significant changes in the level of pro-inflammatory cytokines.This is the first report on drug resistance-modifying potential of CD through inhibition of MDR efflux pump.

Column chromatography of the ethyl acetate extract of the seed pod resin of Hymenaea courbaril var. stilbocarpa furnished a fraction containing a mixture of two new clerodanes and a known clerodane diterpene. Due to the similarity of the structures, they could not be separated by ordinary chromatography even using silica gel impregnated with AgNO3. Thus, an intense study was made in order to optimize the semipreparative separation of this mixture by HPLC (high performance liquid chromatograph) using several different stationary and mobile phases. The best conditions for separation of these diterpenes was on octadecyl-bonded silica with methanol:water:formic acid (85:15:1, v/v/v) as mobile phase, flow rate at 2 mL/min, and UV detection at 240 nm. The fractions obtained were analyzed by gas chromatography-mass spectrometry (GC-MS).

A new neo-clerodane diterpene, named ajugacumbin J (1), together with 13 known compounds (2–14) was isolated from Ajuga decumbens. The structure of ajugacumbin J (1) was elucidated by 1D and 2D NMR spectra and MS. Ajugacumbin J (1) and ajugacumbin D (5) exhibited inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages with an IC50 value of 46.2 and 35.9 μM, respectively.

The clerodane diterpene trans-dehydrocrotonin extracted and isolated from the stem bark of Croton cajucara Benth. was investigated for its lipid-lowering effect in mice fed on a high-fat diet. Mice fed on a high-fat diet for a two-week period demonstrated significantly increased blood levels of total cholesterol and triglycerides, compared with normal controls. Oral treatment with trans-dehydrocrotonin at a dose of 25 or 50 mg kg−1 daily markedly suppressed the high-fat-diet associated rise in total cholesterol and triglyceride levels. The hypocholesterolaemic effect of trans-dehydrocrotonin was more prominent at the dose of 50 mg kg−1 with significant decreases in high-density lipoprotein, very-low-density lipoprotein and low-density lipoprotein cholesterol levels. The lower atherogenic index of the trans-dehydrocrotonin-treated groups suggests the hypolipidaemic potential of this plant-based drug. These results indicate that orally administered trans-dehydrocrotonin is effective in suppressing high-fat-diet-induced hyperlipidaemia in mice and suggest its likely beneficial use as anti-atherogenic agent.

Aparisthmium cordatum (JUSS.) BAIL. (Euphorbiaceae) is a medium sized tree native to the North Brazilian coastal region, which is known in the State of Para as "ariquena queimosa." To our knowledge it has no popular use. Phytochemical studies of the benzene extract of the bark of A. cordatum yielded a futan diterpene with a clerodane skeleton, called cordatin. Recently, we reported the antiulcerogenic activity of trans-dehydrocrotonin (DHC), another furan diterpene isolated from Croton cajucara bark, in different ulcerogenic models in mice and rats. The aim of the present study was to assess the possible antiulcerogenic activity of cordatin, another compound of the clerodane diterpene group present in A. cordatum bark. When previously administered (p.o.) at the doses of 100 mg/kg, cordatin significantly reduced (p

A new clerodane diterpene, 15-hydroxy-16-acetoxy-ent-clerod-3-en-18-oic acid (1), together with three known clerodane diterpenes (2-4) and three known flavones (5-7), were isolated from the aerial parts of Baccharis gaudichaudiana. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 2, 3, and 5 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.

The structure of the clerodane diterpene C21H30O5, with modest antibacterial activity and isolated from the plant Pulicaria wightiana, was established to be meth­yl 6α-hydr­oxy-3,13-clerodadien-15,16-olid-18-oate. The fused six-membered rings of the deca­lin system have sofa and chair conformations. The furan­one side chain is in an antiperiplanar conformation. The mol­ecules in the crystal structure are stabilized by an intra­molecular O—H⋯O hydrogen bond and a chain of inter­molecular C—H⋯O inter­actions.

The present study evaluated the gastroprotective effect of epoxy clerodane diterpene (ECD), isolated from Tinospora cordifolia on indomethacin-induced gastric ulcer in rats. Administration of indomethacin exhibits extreme levels of ulcer index (UI) and myeloperoxidase (MPO) activity. Indomethacin down regulated PGE2, anti-inflammatory cytokines (IL-4, IL-10) and pro-angiogenic factors (VEGF and EGF). The ECD pretreatment considerably increased the levels of PGE2, anti-inflammatory cytokines and pro-angiogenic factors. The ulcer-healing activity of ECD was inhibited by pre-administration of the specific COX-1 inhibitor (SC560) and nonspecific NOS inhibitor (L-NAME), which indicates the involvement of PGE2 and NOS in ECD induced ulcer healing activity. These findings suggest that ECD exerts its antiulcer activity by reinforcement of defensive elements and diminishing the offensive elements.

The new clerodane diterpene methyl 3-oxo-12-epibarbascoate was isolated from the stem barks of Croton urucurana together with the known diterpene methyl 12-epibarbascoate. The structures of these compounds were elucidated by spectroscopic techniques and comparison with the literature data. The obtainment of crystals allowed the crystallographic analysis of X-ray diffraction of diterpenes, thus confirming the proposed structures. O novo diterpeno clerodano 3-oxo-12-epibarbascoato de metila foi isolado das cascas do caule de Croton urucurana, juntamente com o diterpeno conhecido como 12-epibarbascoato de metila. As estruturas destes compostos foram elucidadas através de técnicas espectroscópicas e por comparação com dados da literatura. A obtenção de cristais possibilitou a análise cristalográfica da difração de raios X dos diterpenos, confirmando assim as estruturas propostas.

The new clerodane diterpene methyl 3-oxo-12-epibarbascoate was isolated from the stem barks of Croton urucurana together with the known diterpene methyl 12-epibarbascoate. The structures of these compounds were elucidated by spectroscopic techniques and comparison with the literature data. The obtainment of crystals allowed the crystallographic analysis of X-ray diffraction of diterpenes, thus confirming the proposed structures.

The first phytochemical investigation of Casearia graveolens twigs led to the isolation and identification of a new clerodane diterpene, caseariagraveolin (1), together with six known compounds (2–7). Their structures were elucidated by intensive analysis of their spectroscopic data. Compound 1 showed strong cytotoxicity against oral cavity and breast cancer cell lines with IC50 values of 2.48 and 6.63 μM, respectively.

A neo-clerodane diterpene, 15-hydroxy-15,16-epoxy-6α-neo-cleroda-3,13(16),14-triene-18,19:20,12-diolide, C20H22O6, showing antifeedant activity against lepidopterous pests, has been isolated from Teucrium tomentosum and characterized by NMR and X-ray crystallographic methods. The crystallographic studies reveal that the cyclo­hexene and cyclo­hexane rings adopt a half-chair and a chair conformation, respectively. The furan ring exhibits rotational disorder. The mol­ecules in the crystal structure are stabilized by a network of O—H⋯O and C—H⋯O hydrogen bonds.

A new diterpene, viz. 3beta-acetoxy-4alpha,18:15,16-diepoxy-6beta,12-dihydroxyneocleroda-13(16),14-dien-19,20-olide, C(22)H(28)O(8), exhibiting antifeedant activity against Spodoptera litura was isolated from the aerial parts of Teucrium tomentosum and its structure is reported. One of the two fused rings has a distorted-chair conformation and the other has a chair conformation. The molecules in the crystal are stabilized via O--H...O and C--H...O hydrogen bonds.

A new ent-clerodane diterpene, named bacchariol (1) was isolated from the aerial parts of Baccharis gaudichaudiana DC. (Compositae), together with known ent-clerodane diterpenes (2, 3), eight known flavonoids (4-11) and 3, 5-dicaffeoylquinic acid (12). Their structures were determined by spectroscopic analyses. Flavonoids (7, 8, 11) and 12 showed moderate scavenging activities toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals.

Cordifolide A (1), a novel unprecedented sulfur-containing clerodane diterpene glycoside, together with other two new diterpene glycosides, cordifolides B (2) and C (3), and four known analogues, was isolated from a methanol-soluble extract of the stems of Tinospora cordifolia. The structures of the new compounds were determined on the basis of spectroscopic data interpretation, with that of cordifolide A (1) confirmed by a single-crystal X-ray crystallographic analysis. All isolates were evaluated for their in vitro immunomodulatory activity using mouse bone marrow-derived dentritic cells (BMDCs). (Supported by grant RC4 AI092624, from NIAID, NIH)

Seven new clerodane-type diterpenoids, named peronemins B2 (1), A2 (2), B1 (3), C1 (4), B3 (5), A3 (6), and D1 (7), were isolated from the leaves of Peronema canescens (Verbenaceae), an Indonesian medicinal plant collected in Bengkulu, Sumatera Island, Indonesia. The chemical structures of 1-7 have been elucidated on the basis of their chemical and physicochemical properties.

A new ent-clerodane and two known ent-labdanes were isolated from the barks of Hymenaea courbaril var. altissima (Ducke). The new diterpene was identified, after esterification with diazomethane, as methyl (-)-(5R,8S,9S,10R)-clerod-3-en-15-oate and known diterpenes were identified as methyl (-)-copalate and methyl (-)-eperuate. From the EtOAc extract of seed pods a known methyl (-)-zanzibarate was isolated. The structures of isolated compounds were elucidated based on spectroscopic studies. Da casca do tronco de Hymenaea courbaril var. altissima (Ducke) foi isolado um novo ent-clerodano na forma de éster metílico, após esterificação com diazometano, o (-)-(5R,8S,9S,10R)-clerod-3-en-15-oato de metila. Foram isolados também dois ent-labdanos conhecidos: o (-)-copalato de metila e (-)-eperuato de metila. Do extrato AcOEt do epicarpo foi isolado, após esterificação com diazometano, o (-)-zanzibarato de metila. As estruturas dos compostos foram elucidadas com base na análise de dados espectroscópicos.

Diethylether extracts of New Zealand liverworts Jamesoniella colorata and Bazzania novae-zelandiae were investigated to reveal novel terpenoids. The former extract afforded a new modified clerodane-type diterpenoid, and the latter gave a degraded clerodane (rearranged drimane) type sesquiterpenoid. The structures of those new compounds were established by 2D NMR spectra.