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Made available in DSpace on 2021-06-25T10:47:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Casearia sylvestris is an outstanding representative of the Casearia genus. This representability comes from its distinctive chemical profile and pharmacological properties. This species is widespread from North to South America, occurring in all Brazilian biomes. Based on their morphology, 2 varieties are recognized: C. sylvestris var. sylvestris and C. sylvestris var. lingua. Despite the existence of data about their chemical composition, a deeper understanding of the specialized metabolism correlation and variation in respect to environmental factors and its repercussion over their biological activities was still pending. In this study, an UHPLC-DAD-based metabolomics approach was employed for the investigation of the chemical variation of 12 C. sylvestris populations sampled across 4? Brazilian biomes and ecotones. The correlation between infraspecific chemical variability and the cytotoxic and antioxidant activities was achieved by multivariate data analysis. The analyses showed that C. sylvestris var. lingua prevailed at Cerrado areas, and it was correlated with lower cytotoxic activity and high level of glycosylated flavonoids. Among them, narcissin and isorhamnetin-3- O-α -L-rhamnopyranosyl-(1 → 2)- α -L-arabinopyranoside showed good correlation with the antioxidant activity. Conversely, C. sylvestris var. sylvestris prevailed at the Atlantic Forest areas, and it was associated with high cytotoxic activity and high content of clerodane diterpenoids. Different casearins showed good correlation (R 2= 0.3?-?0.70) with the cytotoxic activity. These findings highlighted the great complexity among different C. sylvestris populations, their chemical profile, and the related biological activities. Consequently, it can certainly influence the medicinal properties, as well as the quality and efficacy, of C. sylvestris phytomedicines. Institute of Chemistry Department of Biochemistry and Organic Chemistry São Paulo State University (UNESP), CEP 14800-060, Rua Prof. Francisco Degni 55 Natural Products Laboratory Institute of Biology Leiden University Natl. Inst. of Alternative Technol. for Detection Toxicological Assess. Removal of Micropollutants and Radioactive Substances Araraquara Agronomic Institute of Campinas Herbarium IAC Department of Biophysics and Physiology Laboratory of Experimental Cancerology Federal University of Piauí Department of Physiology and Pharmacology Faculty of Medicine Federal University of Ceará Institute of Chemistry Department of Biochemistry and Organic Chemistry São Paulo State University (UNESP), CEP 14800-060, Rua Prof. Francisco Degni 55

Natural metabolites with their specific bioactivities are being considered as a potential source of materials for pharmacological studies. In this study, we successfully isolated and identified five known clerodane diterpenes, namely 16-oxo-cleroda-3,13(14)E-dien-15-oic acid (1), 16-hydroxy-cleroda-3,13-dien-15-oic acid (2), 16-hydroxy-cleroda-4(18),13-dien-16,15-olide (3), 3α,16α-dihydroxy-cleroda-4(18),13(14)Z-dien-15,16-olide (4), and 16α-hydroxy-cleroda-3,13(14)Z-dien-15,16-olide (5) from the methanolic extract of seeds of Polyalthia longifolia. Initially, all the isolated metabolites were investigated for COX-1, COX-2, and 5-LOX inhibitory activities using the standard inhibitory kits. Of which, compounds 3, 4, and 5 exhibited to be potent COX-1, COX-2, and 5-LOX inhibitors with the IC50 values similar or lower to those of the reference drugs. To understand the underlying mechanism, these compounds were subjected to molecular docking on COX-1, COX-2, and 5-LOX proteins. Interestingly, the in silico study results were in high accordance with in vitro studies where compounds 3, 4, and 5 hits assumed interactions and binding pattern comparable to that of reference drugs (indomethacin and diclofenac), as a co-crystallized ligand explaining their remarkable dual (COX/LOX) inhibitor actions. Taken together, our findings demonstrated that compounds 3, 4, and 5 functioned as dual inhibitors of COX/5-LOX and can contribute to the development of novel, more effective anti-inflammatory drugs with minimal side-effects.

Covering: 2000 to 2020 The hallucinogenic diterpene salvinorin A potently and selectively agonizes the human kappa-opioid receptor (KOR). Its unique attributes-lack of a basic nitrogen, rapid brain penetrance, short half-life-combined with the potential of KOR as an emerging target for analgesics have stimulated extensive medicinal chemistry based on semi-synthesis from extracts of Salvia divinorum. Total synthesis efforts have delivered multiple, orthogonal routes to salvinorin A, its congeners and related analogs with the goal of optimizing its activity towards multiple functional endpoints. Here we review total syntheses of the salvinorin chemotype and discuss outstanding problems that synthesis can address in the future.

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.

Phytochemical investigation of the leaves and twigs of Callicarpa cathayana led to the isolation of six new clerodane diterpenoids, cathayanalactones A–F (1–6), together with seven analogues (7–13). Their structures were established by extensive NMR analyses together with experimental and calculated ECD spectra analyses. Compounds 1, 2, 3, 7 and 11 showed inhibitory activities on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.

The bioactivity-guided isolation on the Scutellaria barbata extract resulted in the purification of four undescribed neo -clerodane diterpenoids, scuttenlines A-D ( 1-4 )，alone with 20 known diterpenoids ( 5-24 ). The chemical structures of them were elaborated by extensive spectroscopic means, including 1D, 2D-NMR and HR-MS. The anti-inflammatory potential ability of 1 - 24 was screened in lipopolysaccharide-stimulated mouse RAW 264.7 cells. Scuttenline C (IC 50 = 1.9 µM) and 18 (IC 50 = 3.7 µM) exhibited potent activity to inhibit NO production.

Phytochemical investigation of the leaves and twigs of Croton yanhuii led to the isolation of seven highly modified nor-clerodane diterpenoids (1-7), including three new ones, croyanoids A-C (1-3), along with four known analogues (4-7). Compound 1 incorporates a 5,12-epoxy ring, forming a unique cage-like, 6/6/6/5-fused tetracyclic ring system. Their structures were established by extensive spectroscopic analysis, and the absolute configurations of 1-4 were determined by a combination of circular dichroism (CD) analysis and single-crystal X-ray diffraction. All compounds were tested in an array of bioassays, but were inactive. Crotoeurin A (7), a nor-clerodane dimer with a high yield of 0.2‰ isolated in current study, was considered as a chemotaxonomic marker for this species.

Dietary supplements based on Teucrium chamaedrys L. subsp. chamaedrys aerial parts were banned, due to the hepatotoxicity of furan-containing neo-clerodane constituents. Indeed, the plant leaf content in phenolic compounds could be further exploited for their antioxidant capability. Accordingly, bio-guided fractionation strategies have been applied, obtaining seven partially purified extracts. These latter were chemically investigated through 1D and 2D NMR techniques and tested for their antiradical, reducing and cytotoxic capability. Data acquired highlighted that, through a simple phytochemical approach, a progressive neo-clerodane depletion occurred, while maximizing phenylethanoid glycosides in alcoholic fractions. Thus, although the plant cannot be used as a botanical remedy as such, it is suggested as a source of healthy compounds, pure or in mixture, to be handled in pharmaceutical, nutraceutical and/or cosmeceutical sectors.

A search for bioactive natural products as anticancer lead compounds resulted in the isolation of one previously undescribed and three known clerodane diterpenoids (1–4) from Casearia kurzii. The structures of these compounds were established by analysis of their NMR, MS, and electronic circular dichroism data. The cytotoxic activities of four compounds against three human cancer cell lines were evaluated. Compound 2 was found to be the most active with an IC50 value of 4.1 μM against HeLa cells, and was selected to investigate the possible cytotoxic mechanism.

A phytochemical investigation to obtain bioactive substances as lead compounds or agents for cancer led to the obtainment of six new clerodane diterpenoids, designated as kurzipenes A–F (1–6), from the leaves of Casearia kurzii. Their structures were elucidated on the basis of NMR spectroscopic data analysis and the absolute configurations were confirmed by the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The cytotoxic activities of compounds 1–6 were evaluated against human lung cancer A549 cell line, human cervical cancer Hela cell line, and human hepatocellular carcinoma HepG2 cell line. Most diterpenoids showed potent cytotoxicities against the three selected cancer cell lines. The preliminary mechanism studies revealed that the most active compound 2, with an IC50 value of 5.3 μM against Hela cells, induced apoptosis and arrested the Hela cell cycle at the G0/G1 stage to exert cytotoxic effects.

Teucrium yemense, a medicinal plant commonly grown in Saudi Arabia and Yemen, is traditionally used to treat infections, kidney diseases, rheumatism, and diabetes. Extraction of the dried aerial parts of the plant with methanol, followed by further extraction with butanol and chromatography, gave twenty novel neoclerodanes. Their structures, relative configurations and some conformations were determined by MS and 1-D and 2-D NMR techniques. Most were fairly conventional but one contained an unusual stable orthoester, one had its (C-16)–(C-13)–(C-14)–(C-15) (tetrahydro)furan unit present as a succinic anhydride and one had a rearranged carbon skeleton resulting from ring-contraction to give a central octahydroindene bicyclic core, rather than the usual decalin. Mechanisms are proposed for the biosynthetic formation of the orthoester and for the ring-contraction. Four novel neoclerodanes increased the glucose-triggered release of insulin from isolated murine pancreatic islets by more than the standard drug tolbutamide, showing that they are potential leads for the development of new anti-diabetic drugs.

Made available in DSpace on 2020-12-11T17:20:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-20 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Rationale Clerodane-type diterpenes from Casearia species show important pharmacological activites such as antitumor, antimicrobial and anti-inflamatory. There are several mass spectrometry (MS)-based methods for identification of diterpenes; however, there is still a lack of MS procedures capable of providing characteristic fragmentation pathways for a rapid and unambiguous elucidation of casearin-like compounds. Methods Casearin-like compounds were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The fragmentation studies were carried out by tandem mass spectrometry in space (quadrupole time-of-flight (QTOF)) using different collision energies and also by tandem mass spectrometry in time (QIT) by selective isolation of product ions. Results Casearin-like compounds presented a predominance of sodium- and potassium-cationized precursor ions. Both QIT and QTOF techniques provided sequential neutral losses of esters related to the R-1 to R-5 substituents linked to the nucleus of the clerodane diterpenes. The fragmentation pathway is initiated with a cleavage of the ester moieties R-2 followed by the elimination of the ester groups R-3, both losing neutral carboxylic acids. Using QIT, it was also possible to observe the cleavage of the ester groups R-1 or R-5 by MS4 experiments. Conclusions Through a rational analysis of the fragmentation mechanisms of Casearia diterpenes it was possible to suggest an annotation strategy based on the sequential cleavages of the ester groups related to the R-2, R-3 and R-5 substituents. These results will assist studies of the dereplication and metabolomics involving casearin-like compounds present in complex extracts of Casearia species. Univ Sao Paulo, Ribeirao Preto Sch Pharmaceut Sci, Ribeirao Preto, SP, Brazil Univ Fed Uberlandia, Inst Chem, Uberlandia, MG, Brazil Sao Paulo State Univ, Sch Pharmaceut Sci, Lab Pharmacognosy, Araraquara, SP, Brazil York Univ, Dept Chem, Ctr Res Mass Spectrometry, Toronto, ON, Canada Sao Paulo State Univ, Inst Chem, Araraquara, SP, Brazil Imperial Coll London, Dept Life Sci, Silwood Pk Campus, Ascot, Berks, England Univ Fed Piaui, Chem Dept, Teresina, Piaui, Brazil Sao Paulo State Univ, Sch Pharmaceut Sci, Lab Pharmacognosy, Araraquara, SP, Brazil Sao Paulo State Univ, Inst Chem, Araraquara, SP, Brazil CNPq: 207745/2014-5 CNPq: INCT 465637/2014-0 CAPES: 001 FAPESP: 2011/21440-3 FAPESP: 2012/23775-5 FAPESP: 2013/07600-3 FAPESP: 2014/50926-0 FAPESP: 2016/13292-8 FAPESP: 2017/19702-6

Tinospora crispa is a popular traditional herbal plant commonly used throughout the world for treatment of various diseases, in particular type 2 diabetes mellitus. We report here a new case of toxic hepatitis in a 57-year old male patient in the French West Indies following the consumption of two aqueous extracts of fresh Tinospora crispa stems. It thus differs from two previously reported cases that concerned the chronic intake of powdered dry stems delivered in solid oral dosage forms (i.e. pellets and tablets). Liquid Chromatography-Diode Array Detection-Mass Spectrometry (LC/DAD/MS) analyses were performed on an aqueous extract of the offending sample that mimics the swallowed preparation. They revealed the presence of species-specific molecular marker borapetoside C (1) and thus enabled an unambiguous phytochemical identification. The exploration of tandem MS/MS data obtained by ultra-high performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-HRMS) allowed the identification of 17 additional cis-clerodane-type furanoditerpenoid lactones, analogues of 1. These results support the hypothesis that the mechanisms underlying hepatotoxicity of Tinospora crispa are the same as those encountered with furanoditerpenoids-containing plants such as Teucrium chamaedrys or Dioscorea bulbifera. In the context of type 2 diabetes treatment, we recommend that Tinospora crispa intake should be more closely monitored for signs of hepatotoxicity.

Detailed phytochemical investigation of the roots of Erythrophleum fordii furnished seven undescribed cassane-type diterpenoids, erythrocassanoids A-E and erythro-norcassanoids A, B and two known clerodane diterpenes, 15-hydroxy-3-cleroden-2-one and methyl ester of 2-oxopopulifolic acid. Their structures were determined by 1D, 2D NMR and HRESIMS analysis. The antiviral activities of these compounds were evaluated. Among them, 15-hydroxy-3-cleroden-2-one and methyl ester of 2-oxopopulifolic acid showed antiviral activities against influenza virus and coxsackie virus with IC50 values ranging from 11.11 to 29.60 μM.

Natural products have made remarkable contributions to drug discovery and therapy. In this work we exploited various biochemical approaches to investigate the mode of action of 16-α-hydroxy-cleroda-3,13 (14)-Z-dien-15,16-olide (HDK-20), which we recently isolated from Polyalthia longifolia, on Trypanosoma brucei bloodstream trypomastigotes. HDK20 at concentrations ≥ EC50 (0.4 μg/ml) was trypanocidal, with its effect irreversible after only a brief exposure time (T. brucei. Overall, HDK20 showed a multi-target mechanism of action, which provides a biochemical explanation for the promising anti-trypanosomatid activity in our previous report.

The isolation studies of a crude MeOH/ CH(2)Cl(2) (1:1) extract (N005829) of the bark of Laetia corymbulosa yielded 15 new clerodane diterpenes, designated corymbulosins I−W (1−15), as well as four known diterpenes, 16−19. The structures of 1−15 were characterized on the basis of extensive 1D and 2D NMR and HRMS analyses. The absolute configurations of newly isolated compounds 1−15, as well as known 16−19, which were reported previously with only relative configurations, were determined through ECD experiments, X-ray analysis, chemical methods, including Mosher esterification, and comparison of their spectroscopic data. The isolated compounds were evaluated for cytotoxicity against human cancer cell lines. Flow cytometric and immunocytochemical observations of cells treated with cytotoxic clerodanes demonstrated that the chromatin was fragmented and dispersed with formation of apoptotic microtubules.

Scuteformoids A-J, ten previously undescribed neo- clerodane diterpenoids along with one known analogue, were isolated from petroleum ether soluable fraction of the whole plants of Scutellaria formosana . The differences among these compounds are the substituents and stereochemistry at C-13. Their structures were elucidated by 1D and 2D NMR experiments, and the absolute configurations of Scuteformoids A, C, E, F, and I were further confirmed by single-crystal X-ray diffraction. Scuteformoids A, C, D, F, H, and I were evaluated for their inhibitory effects against HIV lytic replication and cytotoxic activities. All of them showed weak anti-HIV activities, with EC 50 values ranging from 48.24 to 79.17 μg/mL.

A phytochemical study on Scutellaria formosana afforded five previously undescribed spiro-diterpenoids, scutellapenes A−E. The structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established by the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. Scutellapenes B−E possess a spiro-diterpenoid skeleton. All of the compounds showed inhibitory effects on LPS-induced nitric oxide (NO) production in murine microglial BV-2 cells. The further molecular docking studies revealed that these bioactive compounds had strong interactions with the iNOS protein.

Five new neo-clerodane diterpenoids, tiliifolins A-E (1-5), along with ten known ones, were isolated from the aerial part of Salvia tiliifolia. Their structures were proposed based on 1D and 2D NMR spectroscopic data analysis. All new compounds were evaluated for their neurotrophic activity on PC12 cells and cytotoxicity against five human cancer cell lines (HL-60, A-549, SMMC-7721, MCF-7, and SW480), and compound 5 showed statistically significant neuroprotective effect in vitro assay.

The first phytochemical investigation from the stems of Croton krabas resulted in the isolation of three new ent-clerodane diterpenoids, crotonkrabases A–C (1–3), along with two known compounds, 12-oxohardwickiic acid (4) and crotonpyrone B (5). Their structures were elucidated using extensive spectroscopic methods. The structure of 3 was unambiguously proven by X-ray crystallography. Furthermore, the absolute configurations of compounds 1–3 were identified by NOESY and the comparison of their experimental ECD spectra with those of calculated ECD spectra reported in the literature. Compounds 1, 2, and 5 showed antibacterial activities against two Gram-positive bacteria (Bacillus cereus and Bacillus subtilis); whereas compound 4 exhibited weak antibacterial against B. cereus. In addition, compound 4 showed potent α-glucosidase inhibitory activity, which was lower than the reference standard acarbose.

Three unprecedented dimeric clerodane diterpenoids, dodovisdimers A-C (1-3), along with six known clerodane monomers (4-9), were isolated from Dodonaea viscosa. Compounds 1-3 may be biosynthetically formed via an intermolecular Diels-Alder [4+2] cycloaddition between the coexisting monomers 4-7. The structures of these clerodanes were characterized by spectroscopic techniques, X-ray crystallographic study, and ECD calculations. Some isolates exerted antiviral effects on human influenza A virus (H3N2) in vitro.

The Lamiaceae plant Ajuga forrestii Diels is a traditional Chinese herbal medicine with abundant glandular trichomes (GTs), but their chemistry and biological functions remain uninvestigated. Here, a panel of six highly functionalized neo-clerodane diterpenoids was localized to the peltate GTs of A. forrestii using laser microdissection coupled with HPLC analysis, indicating that the GTs of A. forrestii are an excellent material for the elucidation of the yet unclear biosynthetic pathway of natural neo-clerodane diterpenoids. In addition, four undescribed neo-clerodane diterpenoids with an acyclic C-9 side chain including two pairs of 1:1 mixture of inseparable diastereomers, ajuforrestins D-G, were isolated from the fresh leaves of A. forrestii together with six known compounds. The structures of the undescribed compounds were elucidated by spectroscopic (including 1D and 2D NMR and HR-ESI-MS) analyses. Biological assays indicated that the major GT compound ajugacumbin B and undescribed ajuforrestins D/E showed antifeedant activity against Helicoverpa armigera, suggesting that neo-clerodanes in A. forrestii should be involved in plant defence against insects. Moreover, the abietane diterpenoid ajuforrestin B exhibited significant anti-inflammatory activity on the secretion of interleukin-2 (IL-2) and cytotoxicity against three cancer cell lines, NCI-H1975, HepG2 and MCF-7, suggesting that ajuforrestin B could positively contribute to the therapeutic effects of this traditional Chinese medicine.

Eleven new compounds, including six labdane (1-6), three halimane (7-9), and two clerodane (10-11) diterpenoids and 16 known analogues (12-27), were isolated from the leaves of Vitex trifolia. The structures of 1-11 were established by extensive 1D- and 2D-NMR and HRMS spectroscopic data. The absolute configurations of compounds 3, 7, and 10 were assigned using X-ray diffraction. Compounds 1-27 were evaluated for DNA topoisomerases I (Top1) inhibitory activity and cytotoxicity against HCT 116 cells. Compounds 8 and 11 exhibited equipotent Top1 inhibitory activity to the positive control, camptothecin (CPT), at 100μM. Compounds 8, 9, 16, and 27 showed moderate cytotoxicity at low micromolar concentrations.

We developed an immunochromatographic assay (ICA) that enables rapid analysis of salvinorin A (Sal A) in Salvia divinorum within 10 min. The result shows that no Sal A in other samples of Lamiaceae plants was detected, but it could recognize Sal A among other substances in complex samples. The main advantage of the ICA is its high performance in combination with low cost, simplicity, and speed. Our newly developed combined ICA/indirect competitive ELISA(icELISA) system enables analysis of large numbers of samples over short periods of time without cumbersome pretreatments in complex mixtures. This method can complement other instrumental analyses for salvinorins, and could be used to deter S. divinorum abuse.

Until the mid-60s, only the Mazatecs, an indigenous group from Oaxaca, Mexico, used Salvia Divinorum (S. divinorum ) due to its hallucinogen properties. Later it was found that the hallucinogen effects of this plant were caused by the presence of a neoclerodane diterpene Salvinorin A (salvinorin A), which is a highly selective agonist of kappa -opioid receptor (KOR) that cause more intense hallucinations than the common hallucinogens as lysergic acid, mushrooms, ecstasy and others. In fact, smoking of only 200–500 μg of S. divinorum leaves is enough to produce these effects thus making it the most potent natural occurring hallucinogen known. Due to its legal status in various countries, this compound has gained a worldwide popularity as a drug of abuse with an easy access through smartshops and internet. Furthermore, salvinorin A gathered an increased interest in the scientific community thanks to its unique structure and properties, and various studies demonstrated that salvinorin A has antinociceptive, antidepressant, in some circumstances pro-depressant and anti-addictive effects that have yielded potential new avenues for research underlying salvinorin A and its semi-synthetic analogs as therapeutic agents.

A bioactive CH3OH–CH2Cl2 (1:1) extract of the bark of Laetia corymbulosa provided five new clerodane diterpenes with an isozuelanin skeleton, designated as corymbulosins D–H (1–5), as well as the known corymbulosins B (6) and C (7), for which the relative configurations were not previously determined. The structures of 1–5 were characterized on the basis of 1D and 2D NMR spectroscopic and HRMS analysis. The absolute configurations of all isolated compounds 1–7 were verified through chemical methods, including modified Mosher esterifications or oxidation of the hydroxy group at C-2, ECD experiments, and spectroscopic data comparison. The isolated compounds were evaluated for antiproliferative activity against a small panel of human cancer cell lines.

Summary Salvia divinorum commonly known as diviner's sage, is an ethnomedicinal plant of the mint family (Lamiaceae). S. divinorum is rich in clerodane-type diterpenoids, which accumulate predominantly in leaf glandular trichomes. The main bioactive metabolite, salvinorin A, is the first non-nitrogenous natural compound known to function as an opioid-receptor agonist, and is undergoing clinical trials for potential use in treating neuropsychiatric diseases and drug addictions. We report here the discovery and functional characterization of two S. divinorum diterpene synthases (diTPSs), the ent-copalyl diphosphate (ent-CPP) synthase SdCPS1, and the clerodienyl diphosphate (CLPP) synthase SdCPS2. Mining of leaf- and trichome-specific transcriptomes revealed five diTPSs, two of which are class II diTPSs (SdCPS1-2) and three are class I enzymes (SdKSL1-3). Of the class II diTPSs, transient expression in Nicotiana benthamiana identified SdCPS1 as an ent-CPP synthase, which is prevalent in roots and, together with SdKSL1, exhibits a possible dual role in general and specialized metabolism. In vivo co-expression and in vitro assays combined with NMR analysis identified SdCPS2 as a CLPP synthase. A role of SdCPS2 in catalyzing the committed step in salvinorin A biosynthesis is supported by its biochemical function, trichome-specific expression and absence of additional class II diTPSs in S. divinorum. Structure-guided mutagenesis revealed four catalytic residues that enabled the re-programming of SdCPS2 activity to afford four distinct products, thus advancing our understanding of how neo-functionalization events have shaped the array of different class II diTPS functions in plants, and may promote synthetic biology platforms for a broader spectrum of diterpenoid bioproducts. This article is protected by copyright. All rights reserved.

Highlight The class II diterpene synthase that catalyzes the first committed reaction of the virtually unknown biosynthetic pathway of salvinorin A in Salvia divinorum is identified and the structural basis for product specificity of this enzyme is elucidated., Salvia divinorum (Lamiaceae) is an annual herb used by indigenous cultures of Mexico for medicinal and ritual purposes. The biosynthesis of salvinorin A, its major bioactive neo-clerodane diterpenoid, remains virtually unknown. This investigation aimed to identify the enzyme that catalyzes the first reaction of salvinorin A biosynthesis, the formation of (–)-kolavenyl diphosphate [(–)-KPP], which is subsequently dephosphorylated to afford (–)-kolavenol. Peltate glandular trichomes were identified as the major and perhaps exclusive site of salvinorin accumulation in S. divinorum. The trichome-specific transcriptome was used to identify candidate diterpene synthases (diTPSs). In vitro and in planta characterization of a class II diTPS designated as SdKPS confirmed its activity as (–)-KPP synthase and its involvement in salvinorin A biosynthesis. Mutation of a phenylalanine into histidine in the active site of SdKPS completely converts the product from (–)-KPP into ent-copalyl diphosphate. Structural elements were identified that mediate the natural formation of the neo-clerodane backbone by this enzyme and suggest how SdKPS and other diTPSs may have evolved from ent-copalyl diphosphate synthase.

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.

Opioids are widely used to treat millions suffering from pain, but their analgesic utility is limited due to associated side effects. Herein we report the development and evaluation of a chemical probe exhibiting analgesia and reduced opioid-induced side effects. This compound, kurkinorin (5), is a potent and selective µ-opioid receptor (MOR) agonist (EC50 = 1.2 nM, >8,000 µ/κ selectivity). 5 is a biased activator of MOR-induced G-protein signaling over β-arrestin-2 recruitment. Metadynamics simulations of 5’s binding to a MOR crystal structure suggest energetically preferred binding modes that differ from crystallographic ligands. In vivo studies with 5 demonstrate centrally-mediated antinociception, significantly reduced rewarding effects, tolerance, and sedation. We propose that this novel MOR agonist may represent a valuable tool in distinguishing the pathways involved in MOR-induced analgesia from its side effects.

Made available in DSpace on 2020-12-11T10:26:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 INCT Program [INCT-BioNat] Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Centre for Scientific Computing (NCC/GridUNESP) of Sao Paulo State University (UNESP) Ethnopharmacological relevance: Croton floribundus Spreng. (Euphorbiaceae), popularly known as Capixingui, stands out due to its widespread use in traditional medicine to treat wounds, syphilis, hemorrhoids, eye diseases and as a purgative. Aim of the study: To characterize clerodanes diterpenes from C. floribundus and to evaluate the effects of the fraction and diterpenes (1-5) on inhibition of nitrite production. Materials and methods: The hydroethanolic root extract of C. floribundus was fractionated on a solid phase extraction column to obtain the fraction named Fr80%. From this, five compounds were obtained and characterized. The absolute configuration of compound 1 was determined by a combination of electronic and vibrational circular dichroism spectroscopies. Additionally, compounds 1-5 were evaluated for their inhibitory effects on nitrite production induced by lipopolysaccharide (LPS) in RAW 264 macrophage cell. Results: Five clerodane diterpenoids were characterized, and the absolute stereochemistry of 1 was established as 3R,4R,5R,8R,9R,10S,12S. The IC50 values obtained through inhibition of nitrite production were 28.52 +/- 2.21 mu M (1), 40.26 +/- 2.79 mu M (2), 25.47 +/- 2.16 mu M (3), 35.78 +/- 2.93 mu M (4) and 40.58 +/- 4.78 mu M (5). In the tested concentrations, the samples presented low toxicity in macrophages. Conclusions: Four new diterpenes were characterized from C. floribundus, these being croflorins A-D (1-4) and a known halimane (5). These compounds exhibited inhibitory effect on nitrite production. Sao Paulo State Univ, Inst Chem, BR-14800060 Araraquara, SP, Brazil Fluminense Fed Univ, Inst Chem, BR-24020141 Niteroi, RJ, Brazil Univ Fed Sao Paulo, Inst Sci & Technol, BR-12231280 Sao Jose Dos Campos, SP, Brazil Sao Paulo State Univ, Sch Pharmaceut Sci, BR-01049010 Araraquara, SP, Brazil Sao Paulo State Univ, Inst Chem, BR-14800060 Araraquara, SP, Brazil Sao Paulo State Univ, Sch Pharmaceut Sci, BR-01049010 Araraquara, SP, Brazil INCT Program [INCT-BioNat]: 465637/2014-0 INCT Program [INCT-BioNat]: 2014/50926-0 FAPESP: 2013/07600-3 FAPESP: 2014/25222-9 FAPESP: 2017/19870-6 CAPES: 001 CAPES: 88887.313278/2019-00 CNPq: 142286/2016-8 CNPq: 142014/2018-4 FAPESP: 2017/17098-4 FAPESP: 2019/04381-5 FAPESP: 2017/18807-9

Ethnopharmacological relevance Salvia divinorum Epling & Jativa is a Mexican plant used not only in rituals but also in traditional medicine for pain relief. One of the most known bioactive compounds is salvinorin A, which acts centrally in kappa-type opioid receptors. Aim of the study Despite its traditional use as a medicinal plant, there is not enough scientific investigation to reinforce its potential as analgesic. In this study, Salvia divinorum antinociceptive activity was evaluated in experimental models of nociceptive pain; the writhing test and formalin-induced licking behavior in mice. Material and methods Different Salvia divinorum extracts were prepared by maceration at room temperature in increased polarity (hexane, ethyl acetate and methanol). The ethyl acetate extract (EAEx) was chosen in order to be fractioned and to obtain a mixture of salvinorins. The antinociceptive effect of EAEx (3, 10, 30, and 100 mg/kg, i.p.) was compared with that of tramadol (a partial opioid agonist analgesic drug, 30 mg/kg, i.p.) and the mixture of salvinorins (30 mg/kg, i.p.). In addition, a participation of opioids (naloxone, NX 1 and/or 3 mg/kg, i.p.) and serotonin 5-HT1A receptors (WAY100635, 0.32 mg/kg, i.p.) was investigated as possible inhibitory neurotransmission involved. Results As a result, the EAEx produced significant and dose-dependent antinociceptive effect concerning salvinorins constituents. This effect was blocked in the presence of NX and WAY100635 in the abdominal test, but only by NX in the formalin-induced licking behavior. Whereas, the effect of salvinorins mixture involved opioids and serotonin 5-HT1A receptors. Conclusion Data provide evidence of the potential of this species, where salvinorin A is in part responsible bioactive constituent involving participation of the opioids and/or 5-HT1A serotonin receptors depending on the kind of pain model explored.

The marine sponge Raspailia bouryesnaultae, collected in South Brazil, was selected for detailed investigation considering the results of a screening that pointed to an in vitro antiproliferative effect against non-small cells of human lung cancer (A549) and anti-herpes activity against Herpes Simplex virus type 1 (KOS and 29R strains) of ethanolic extracts. The fractionation and chemical investigation of the sponge&rsquo, s hexanic fraction led to the isolation and structural elucidation of six clerodane diterpenes. The main component was identified as the already-reported raspailol (1), isolated from a sponge of the same genus collected in New Zealand. The structure of a new diterpene (2) with a rearranged skeleton was established by high-resolution mass spectrometry (HRMS) and 1D and 2D Nuclear magnetic resonance spectroscopy (NMR) experiments, and named here as raspadiene. Furthermore, four diterpenes were elucidated as isomers of clerodane diterpenes previously obtained from plants, namely kerlinic acid (3), kerlinic acid methyl ester (4), annonene (5), and 6-hydroxyannonene (6). They differ in their stereochemistry, since these diterpenes are characterized by a trans ring fusion at the decalin moiety and the relative configuration of the two methyl groups at C-8 and C-9 in a cis relationship (type trans/cis). The Raspailia diterpenes have a cis ring fusion at the decalin moiety, and the two methyl groups at C-8 and C-9 are in a trans relationship (type cis/trans). The isolated compounds were evaluated for their potential antiproliferative effects on human cancer cell line A549, and it was observed that the diterpenes bearing a hydroxyl group at C-6 exhibited moderate cytotoxic activity, with 50% inhibitory concentration (IC50) values lower than 25 &mu, M. The evaluation of the potential anti-herpes activity against Herpes Simplex Virus type 1 (HSV-1, KOS and 29R strains) showed that the more promising results were observed for the new compound 2, since it inhibited HSV-1 (KOS and 29R strains) replication by 83% and 74%, respectively.

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.

Six undescribed clerodane diterpenoids, dodovisins A−F, together with nine known ones, were isolated from the aerial parts of Dodonaea viscosa (L.) Jacq. Their structures were elucidated by extensive spectroscopic techniques, X-ray crystallographic analysis, and ECD calculation. Dodovisins A and B possess a rare carbon skeleton featuring a bicyclo[6.2.0]decane motif. Dodovisins C−E represent the first clerodane diterpenoids with a 4(5 → 19)-abeo-2,4,10(1)-triene moiety. Dodovisins A, E, and strictic acid showed potent inhibitory activities against ATP citrate lyase.

Ethnopharmacological relevance Mexico is considered an ancestral center of diversity of Salvia species, however many of them lack scientific information. Salvia circinnata Cav. (syn. Salvia amarissima Ortega) is an endemic species used in traditional medicine to treat disorders attributed to a cold state like anxiety in the central nervous system, as well as gastrointestinal ailments and pain relief. Aim of the study To give preclinical evidence about the pharmacological properties of this species by investigating its antinociceptive and anti-inflammatory effects, the chemical nature of at least one metabolite, and a possible mechanism of action and adverse effects, using different experimental models of pain. Material and methods Different crude extracts of Salvia circinnata Cav. aerial parts were prepared using increasing polarity and evaluated in the formalin test in mice. This screening allowed to select and evaluate an ethyl acetate extract (EtOAc), as the most bioactive extract, and a metabolite. Antinociceptive and anti-inflammatory activities were confirmed using the plantar test and carrageenan-induced edema. The antinociceptive effects of the extracts were compared to that observed with morphine (1 mg/kg), tramadol (20 mg/kg) or indomethacin (20 mg/kg) as reference drugs. Participation of opioids and TRPV1 receptors was investigated, as well as acute toxicity and adverse effects of sedation and gastric damage. Results EtOAc (0.1–10 mg/kg) of S. circinnata Cav. showed a dose-dependent and significant antinociceptive activity, associated in part with the presence of a neo-clerodane glycoside amarisolide A (0.01–1 mg/kg), in the neurogenic and inflammatory phases of the formalin test. Central action of both treatments was corroborated in the plantar test, whereas anti-inflammatory effects were confirmed with the extract (1 and 10 mg/kg) and amarisolide A (1 mg/kg) in the carrageenan-induced edema test. An opioid mechanism in both treatments, and the TRPV1 receptor modulation in the extract were involved. No acute toxicity and adverse effects were noticed with the extract and pure compound in comparison to the reference drugs. Conclusion These results provide preclinical evidence of the ethnopharmacological antinociceptive S. circinnata Cav. properties, in which the neo-clerodane diterpene glycoside amarisolide A was partially responsible involving the participation of the opioid receptors, while TRPV1 receptor modulation was implicated in the anti-inflammatory activity may be because of the presence of other constituents. This information supports the use of this species in folk medicine for pain therapy.

The stem bark and root bark extracts of Croton dictyophlebodes (Euphorbiaceae) yielded seven undescribed ent-clerodanes: 15,16-epoxy-17,12(S)-olide-ent-cleroda-1,3,13(16),14-tetraen-18-oic acid methyl ester (crotodictyo A), 3β,4β:15,16-diepoxy-ent-cleroda-13(16),14-dien-20-al (crotodictyo B), 3β,4β:15,16-diepoxy-ent-cleroda-13(16),14-dien-19,20-dioic acid (crotodictyo C), 3β,4β:15,16-diepoxy-ent-cleroda-13(16),14-dien-20,19-olide (crotodictyo D), 3β,4β:15,16-diepoxy-20,12(R)-olide ent-cleroda-13(16),14-dien-19-oic acid methyl ester (crotodictyo E), 15,16-epoxy-ent-cleroda-3,13(16),14-trien-12-oxo-18-oic acid (crotodictyo F) and 15,16-epoxy-ent-cleroda-1,3,13(16),14-tetraen-12-oxo-18-oic acid (crotodictyo G), in addition to 15,16-epoxy- ent-cleroda-3,13(16),14-trien-12-oxo-18-oic acid methyl ester (crotodictyo H), reported previously as a synthetic derivative, and acetyl aleuritolic acid. The root extract yielded two ent-trachylobanes, ent-trachylobane-18,19-diol, the undescribed ent-trachylobane-2α,19-diol, along with ent-kaur-16-en-19-oic acid and 2-methoxybenzyl benzoate. Compounds were evaluated against the NCI 60 panel of human tumour cell lines at a single dose of 10−5 M, but showed no significant activity.

Ten new (1-10) and seventeen known (11-27) neo-clerodane diterpenoids substituted with nicotinoyloxyl were isolated from the plant Scutellaria barbata and their structures were established by extensive spectroscopic analysis. Chemoreversal effects of these neo-clerodane diterpenoids on multidrug resistance were evaluated in breast cancer multidrug-resistant MCF-7/ADR cells that overexpress P-glycoprotein. Four compounds (11, 14, 16, and 18) exhibited better chemoreversal abilities than the classical P-gp inhibitor verapamil and the most potent compound 11 reduced IC50 value of adriamycin in MCF-7/ADR cells from 58.8 μM to 1.3 μM. Mechanistic investigations showed that compound 11 reversed multidrug resistance through suppressing the activity of P-gp and restraining the expression of P-glycoprotein. In the present study, the structure-activity relationships of neo-clerodane diterpenoids were also discussed.

Three new neo-clerodane diterpenoids, named scutestrigillosins A-C (1-3), were isolated from the whole plant of Scutellaria strigillosa. Their chemical structures including absolute configurations were established on the basis of detailed physical data analyses. In vitro, the isolated three new compounds exhibited significant cytotoxic activities against four tumor cell lines (HONE-1, P-388, MCF7 and HT29), and gave IC50 values in the range 3.5-7.7μM.

Twenty new neo-clerodane type diterpenoids, scutefolides G1-S (1-20), were isolated from the 70 % aqueous acetone extract of the aerial parts of Scutellaria coleifolia. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of 1, 2, 7, 8, 14 and 15 were determined by means of the CD exciton chirality method. Compounds 1, 2, 5, 7, 8, 12, 14, 15, 18 and 19 were evaluated for their cytotoxic activities against four human cancer cell lines, and anti-bacterial activities against methicillin-resistant Staphylococcus aureus.

Two new neo-clerodane diterpenoids, named scutestrigillosins D and E (1 and 2), were isolated from the whole plant Scutellaria strigillosa. Their structures were established on the basis of detailed physical data analyses. In vitro, two new compounds exhibited cytotoxic activities against four tumor cell lines (HONE-1, P-388, MCF7, and HT29), and gave IC50 values in the range of 3.4-8.9 μΜ.

Covering: 1990 to 2015 The clerodane diterpenoids are a widespread class of secondary metabolites and have been found in several hundreds of plant species from various families and in organisms from other taxonomic groups. These substances have attracted interest in recent years due to their notable biological activities, particularly insect antifeedant properties. In addition, the major active clerodanes of Salvia divinorum can be used as novel opioid receptor probes, allowing greater insight into opioid receptor-mediated phenomena, as well as opening additional areas for chemical investigation. This article provides extensive coverage of naturally occurring clerodane diterpenes discovered from 1990 until 2015, and follows up on the 1992 review by Merritt and Ley in this same journal. The distribution, chemotaxonomic significance, chemical structures, and biological activities of clerodane diterpenes are summarized. In the cases where sufficient information is available, structure activity relationship (SAR) correlations and mode of action of active clerodanes have been presented.

Two new clerodane diterpenoids (1-2), one new clerodane diterpenoid alkaloid (3), as well as thirteen known compounds were isolated from Croton crassifolius. The structures of new compounds were established by a combination of spectroscopic methods, including HRMS, (1)H NMR, (13)C NMR, (1)H (1)H COSY, HSQC, HMBC, NOESY and X-ray crystallographic analysis. Compound 3 is firstly reported as the clerodane-type diterpenoid alkaloid in natural products. All of the compounds were evaluated for in vitro cytotoxic activities against CT26.WT cell using the MTT method.

A bioassay-guided phytochemical investigation of the leaves of Casearia balansae led to the isolation of six new cucurbitane-type triterpenoid derivatives (balanterpenes A-F, 1-6) and four new clerdoane-type diterpenoids (balanterpenes G-J, 7-10). The structures of 1-10 were established on the basis of extensive analysis of NMR spectroscopic data, X-ray crystallography, and experimental and calculated electronic circular dichroism spectra. Compound 1 features a ring-expanded triterpenoid skeleton with the C-19 methyl involved in the ring formation, compound 6 possesses a rare hexanortriterpenoid scaffold, and compounds 7-10 may be four new diterpenoid artifacts presumably formed during the extraction and purification processes. Compounds 3 and 7-10 showed promoting effects on neurite outgrowth of PC12 cells with EC50 values in the range 2.9-10.0 μM.

Seven neo-clerodane diterpenes, teufruintins A-G (1-7), together with eight known compounds (8-15) were isolated from the CHCl3-soluble fraction of the aerial parts of Teucrium fruticans cultivated in China. The chemical structures of the isolated compounds were elucidated using different spectroscopic methods. All of the isolated diterpenes were evaluated for their cytotoxic activities on three human cancer cell lines, and for their ability to inhibit LPS-induced nitric oxide production in RAW 264.7 macrophages. None of the compounds displayed cytotoxic activities on the cancer cell lines, and only 15 showed weak NO inhibitory activity.

A phytochemical survey to obtain bioactive natural products from Ajuga pantantha afforded five new neo-clerodane diterpenoids (1–5). The structures were established by analysis of their NMR spectroscopic data, and electronic circular dichroism calculations were applied to define their absolute configurations. Compounds 2 and 5 were found to have the property of inhibiting NO production (IC50 values

In this study, 14 previously undescribed terpenoids were isolated from the Chinese liverwort Heteroscyphus coalitus (Hook.) Schiffner, including a rare harziane type diterpenoid, heteroscyphsic acid A; eight ent-clerodane diterpenoids, heteroscyphsic acids B–I; four labdane diterpenoids, heteroscyphins A–D; and one guaiane sesquiterpene, heteroscyphin E; as well as a known ent-junceic acid. Their structures were determined by a combination of MS, NMR spectroscopy, electronic circular dichroism (ECD) and single crystal X-ray diffraction analyses. The anti-virulence activity of the isolated compounds against Candida albicans DSY654 demonstrated that most of them could block hyphal growth at concentrations ranging from 4–32 μg/ml. Further investigation of the most active compound, heteroscyphin D, revealed that it could suppress the ability of C. albicans DSY654 to adhere to A549 cells and form biofilms, and modulate the transcription of related genes in this fungus.

Plants of the genus Callicarpa are known to possess several medicinal effects. The constituents of the Taiwan endemic plant Callicarpa hypoleucophylla have never been studied. Therefore, C. hypoleucophylla was selected for our phytochemical investigation. Two new clerodane-type diterpenoids, named callihypolins A (1) and B (2), along with seven known compounds were isolated from the leaves and twigs of the Lamiaceae plant C. hypoleucophylla and then characterized. The structures of compounds 1 and 2 were elucidated by spectroscopic data analysis, specifically, two-dimension nuclear magnetic resonance (NMR). The anti-inflammatory activity of compounds 1&ndash, 9 based on the suppression of superoxide anion generation and elastase release was evaluated. Among the isolates, compounds 2&ndash, 4 showed anti-inflammatory activity (9.52&minus, 32.48% inhibition at the concentration 10 &mu, m) by suppressing superoxide anion generation and elastase release. Our findings not only expand the description of the structural diversity of the compounds present in plants of the genus Callicarpa but also highlight the possibility of developing anti-inflammatory agents from Callicarpa endemic species.

Bioactivity guided the isolation of extracts from the aerial parts Scutellaria barbata D. Don to discover neo-clerodane diterpenoids with potent phytotoxic activity. Of the 34 isolates, 13 neo-clerodane diterpenoids were described for the first time. The structures of these undescribed compounds were elucidated by extensive analysis of NMR spectroscopic data, and the absolute configurations of scutebarbolides A and L and scutebata W were determined by X-ray diffraction. The phytotoxic activity of all compounds against the growth of the roots and shoots of L. perenne and L. sativa seedlings were first reported, and some compounds showed considerable inhibitory effects, especially scutebarbolide K, whose inhibition rates were higher than those of the positive control at concentrations ranging from 25 to 200 μg/mL. When L. perenne and L. sativa seedlings were treated at a concentration of 200 μg/mL, scutebarbolide K caused wilting symptoms on and finally death of these two tested plant seedlings. In addition, the structure-activity relationships of these neo-clerodane diterpenoids were also discussed.

A new neo-clerodane diterpenoid, barbatin H (1), together with fifteen known analogues (2-16) were isolated from Scutellaria barbata D.Don. Their structures were determined on the basis of NMR and HR-MS spectral analysis and comparison with the reported data. All of those compounds were comparatively predicted for their cytotoxic activities against four human tumor cell lines, i. e. LoVo (colon cancer), MCF-7 (breast cancer), SMMC-7721 (hepatoma cancer), and HCT-116 (colon cancer) cells by MTT method in vitro. The results turned out that the series of neo-clerodane diterpenoids exhibited varying degrees of cytotoxic activities against the growth of the tested tumor cell lines, and most of them exhibited selective cytotoxicity against LoVo cell lines. Scutebata A (14) showed significant cytotoxic activities against four tested tumor cells with IC50 values of 4.57, 7.68, 5.31, and 6.23 μm, respectively, which indicated that it might be a potential chemotherapeutic agent.