Antimicrobial activity of diterpenes from Viguiera arenaria against endodontic bacteria

Six pimarane-type diterpenes isolated from Viguiera arenaria Baker and two semi-synthetic derivatives were evaluated in vitro against a panel of representative microorganisms responsible for dental root canal infections. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Porphyromonas gingivalis, Prevotella nigrescens, Prevotella intermedia, Prevotella buccae, Fusobacterium nucleatum, Bacteroides fragilis, Actinomyces naeslundii, Actinomyces viscosus, Peptostreptococcus micros, Enterococcus faecalis and Aggregatibacter actinomycetemcomitans. The compounds ent-pimara-8(14),15-dien-19-oic acid, its sodium salt and ent-8(14),15-pimaradien-3β-ol were the most active, displaying MIC values ranging from 1 to 10 μg mL-1. The results also allow us to conclude that minor structural differences among these diterpenes significantly influence their antimicrobial activity, bringing new perspectives to the discovery of new chemicals for use as a complement to instrumental endodontic procedures.     

Evaluation of cytoprotective effects of compounds isolated from Copaifera langsdorffii Desf. against induced cytotoxicity by exposure to methylmercury and lead

Abstract

Copaifera langsdorffii L. is one of the most known medicinal species in Brazil. Its leaves are rich in phenolic compounds with potential biological activities as an antioxidant and chelating agent. This paper reports the isolation of four compounds from the hydroalcoholic extract of the leaves of C. langsdorffii and the investigation of their possible cytoprotective effects against heavy metal poisoning. Quercitrin (1), afzelin (2), 3,5-di-O-(3-O-methyl galloyl) quinic acid (3) and 4,5-di-O-(3-O-methyl galloyl) quinic acid (4), were associated with toxic doses of methylmercury and lead and evaluated by Alamar blue cell viability assays in HepG2 and PC12. The compounds displayed significant cytoprotective effect for the HepG2 cell line against both metals. Compounds 1–4 did not protect PC12 cells against methylmercury induced-cytotoxicity, but at lower concentrations, they protected against lead induced-cytotoxicity. The evaluated compounds showed a promising cytoprotection effect against exposure to heavy metals and should be further investigated as protective agents.     

Chemical composition of essential oils from the vegetative and reproductive structures of Copaifera langsdorffii Desf.

GC/FID and GC–MS analysis revealed germacrene D, bicyclogermacrene, α-cadinol and cubenol as major compounds from aril. Germacrene D, bicyclogermacrene, trans-caryophyllene and δ-elemene are major compounds in fruits. Germacrene D, spathulenol, trans-caryophyllene and caryophyllene oxide are major compounds in leaves. Furthermore, multivariate analysis revealed distinct groups between the composition of essential oils from aril and fruit, when compared with terpene production found in leaves. Lipid composition found in arils could be protected by the presence of non-oxygenated sesquiterpenes, as germacrene D and bicyclogermacrene. Chemical profiles of essential oils from the fruits, arils and leaves of Copaifera langsdorffii Desf. revealed different compositions, which could be related to environmental pressures. Thereby, non-oxygenated sesquiterpenes can also work against herbivory, pathogens and predator's attack, emphasising the importance of further studies among terpenes, ecology interactions and plant physiology.     

A validated chromatographic method for the determination of flavonoids in Copaifera langsdorffii by HPLC

Hydroethanolic extracts of C. langsdorffii leaves have therapeutic potential. This work reports a validated chromatographic method for the quantification of polar compounds in the hydroethanolic extract of C. langsdorffii leaves. A reliable HPLC method was developed using two monolithic columns linked in series (100 x 4.6 mm - C18), with nonlinear gradient elution, and UV detection set at 257 nm. A procedure for the extraction of flavonols was also developed, which involved the use of 70% aqueous ethanol and the addition of benzophenone as the internal standard. The developed method led to a good detection response as the values for linearity were between 10.3 and 1000 microg/mL, and those for recovery between 84.2 and 111.1%. The detection limit ranged from 0.02 to 1.70 microg/mL and the quantitation limit from 0.07 to 5.1 microg/mL, with a maximum RSD of 5.24%. Five compounds, rutin, quercetin-3-O-alpha-L-rhamnopyranoside, kaempferol-3-O-alpha-L-rhamnopyranoside, quercetin and kaempferol, were quantified. This method could, therefore, be used for the quality control of hydroethanolic extracts of Copaifera leaves and their cosmetic and pharmaceutical products.     

Three new ingol diterpenes from Euphorbia nivulia: evaluation of cytotoxic activity

The latex of Euphorbia nivulia afforded three new ingol diterpenes, 3-acetyl-8-methoxyl-7-angolyl-12-hydroxylingol (7), 3,12-diacetyl-7-hydroxy-8-methoxylingol (8), and 3,12-diacetyl-7-angolyl-8-hydroxylingol (9) along with five known ingol diterpenes 2-6 and a known triterpene cyclonivulinol (1). Their structures were established by means of spectroscopic analysis. Diterpenes 2-9 were evaluated for their cytotoxic activity.     

Dehydroabietane from the oleoresin of Pinus pallasiana

Summary The known diterpene hydrocarbon dehydroabietane has been isolated from a natural source — the oleoresin of the Crimean pine — for the first time.Institute of Chemistry, Academy of Sciences of the Moldavian SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 20–22, January, 1971.     

New sesquiterpenoids from the oleoresin of Abies alba

The structures of four new sesquiterpenoids from the oleoresin ofAbies alba have been studied. On the basis of various spectral characteristics, the structures of (10S, 11S)-himachala-2,4-diene, (10S, 11S)-himachala-3(12), 4-diene, humula-4,9-dien-8-ol, and (4S, 5S, 10S)-selina-6-en-4-ol have been proposed for the compounds isolated. The stereochemistry of the asymmetric centers was determined by the conversion of these compounds into known sesquiterpenes and also by analysis of PMR spectra with a shift reagent.Novosibirsk Institute of Organic Chemistry, Siberian Branch, USSR Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 712–718, September–October, 1988.     

Three abietane diterpenes and two diterpenes incorporated sesquiterpenes from the bark of Cryptomeria japonica

Three new abietane diterpenes, sugikurojins D (1), E (2), and F (3), and two new abietanes which incorporate cadinane, sugikurojins G (4) and H (5) were isolated from the bark of Cryptomeria japonica. These structures were elucidated primarily by extensive NMR experiments. The structure of sugikurojin D (1) was deduced to be 6alpha-acetoxy-7beta,11-dihydroxy-12-methoxy-8,11,13-abietatriene. Sugikurojin E (2) was deduced to be 6alpha-acetoxy-7beta,12-dihydroxy-8,11,13-abietatriene. Sugikurojin F (3) was 7alpha-methoxy-8,13-abietadien-11,12-dione. Sugikurojins G (4) and H (5) had a unique skeleton incorporating an alpha-cadinol or a 1alpha-hydroxy-T-cadinol in ferruginol, respectively. Also obtained in this investigation were the known diterpenes (6-14). An antibacterial activity of ten among these against Staphylococcus aureus and Escherichia coli was inactive at the (MIC: 125 microg/ml) level. Meanwhile, in the cytotoxic activity against HL-60, compounds 4, 8, and 11 showed moderate (IC50: 4, 35.4; 8, 28.0; 11, 52.4 microM) though weak (IC50: 4, 100; 8, 80.8; 11, 100 microM) activity against HCT-15.     

Chip-calorimetric evaluation of the efficacy of antibiotics and bacteriophages against bacteria on a minute-timescale

Rapid detection of antibiotic resistances of clinical bacterial strains would allow an early selective antibiotic therapy and a faster intervention and implementation of infection control measurements. In clinical practice, however, conventional antibiotic susceptibility tests of bacteria often need 24 h until the results are obtained. The metabolic heat production of bacteria is an excellent possibility to record their physiological activities and could therefore be used for a rapid discrimination of bacterial strains which are resistant or non-resistant to antibiotics and also to lytic bacteriophages, respectively. Unfortunately, conventional calorimeters suffer from need of comparably large volumes of bacterial suspensions are characterised by slow operation and high costs which restrict their application in clinical laboratories. The present paper demonstrates that a new type of calorimeters developed on silicon-chip technology enables the detection of antibiotic resistances on a minute-timescale. For this reasons, a prototype chip calorimeter was used which sensitivity is 20 nW related to the heat production of about 10⁴ bacteria. For a clear discrimination of antibiotic resistance about 10⁵ bacteria are required. The antibiotic resistances and susceptibilities of different strains of Staphylococcus aureus to cefoxitin and the sensitivities of S. aureus DSM 18421 and E. coli DSM 498 to a mixture of two bacteriophages were studied. Comparing the heat productions of cultures incubated with antibiotics or bacteriophages to those without these antibacterial preparations enabled a clear discrimination of resistant and non-resistant strains already after totally 2 h.     

New cassane-type diterpenes of Caesalpinia crista from Myanmar

Seven new cassane-type diterpenes, caesalpinin MF-ML (1-7), and a new norcassane-type diterpene, norcaesalpinin MD (8), have been isolated from the CH2Cl2 extract of seed kernels of Caesalpinia crista from Myanmar, together with sixteen known cassane-type diterpenes, 7-acetoxybonducellpin C, caesaldekarin e, caesalmin C, caesalmin G, 2-acetoxycaesaldekarin e, zeta-caesalpin, caesalpinin D, caesalpinin E, caesalpinin F, caesalpinin H, caesalpinin I, caesalpinin J, caesalpinin K, caesalpinin M, caesalpinin N, and caesalpinin O. The structures of the isolated compounds were elucidated by the use of spectroscopic techniques.     

Labdane diterpenes from the rhizomes of Hedychium coronarium

A new labdane diterpenoid, (E)-labda-8(17),12-dien-15,16-olide (1) together with eight known compounds, coronarin D (2), coronarin D methyl ether (3), coronarin D ethyl ether (4), isocoronarin D (5), coronarin B (6), labda-8(17),11,13-trien-15,16-olide (7), (E)-labda-8(17),12-diene-15,16-dial (8) and 16-hydroxylabda-8(17),11,13-trien-15,16-olide (9), are isolated from the rhizomes of Hedychium coronarium. Compounds 2-4, 5 and 9 are isolated as mixtures of C-15, C-14 and C-16 epimers, respectively. Their structures are determined on the basis of their spectroscopic data. The epimeric mixtures of 2 and 3 have not been reported before. Some of them were evaluated for their cytotoxicity.     

Structure elucidation of casbane diterpenes from Croton argyrophyllus

Two novel casbane diterpenes 1-hydroxy-(2E,6Z,12E)-casba-2,6,12-triene-4,5-dione (1) and 6E,12E-casba-1,3,6,12-tetraen-1,4-epoxy-5-one (2) were isolated from the ethanol extract of the stems of Croton argyrophyllus. Structural characterization including the relative stereochemistry of all compounds was established on the basis of spectroscopic methods, mainly 1D and 2D NMR, and HRESIMS.     

Capillary electrophoretic separation of phenolic diterpenes from rosemary

The major phenolic diterpenes responsible for the antioxidant properties of rosemary extracts, namely carnosol and carnosic acid, were separated by capillary zone electrophoresis (CZE) using a 56 cm long uncoated fused-silica capillary and a 50 mM disodium tetraborate buffer of pH 10.1. The effect of the buffer type, pH and concentration, and the capillary length on the separation, was studied. Carnosol and carnosic acid were identified in the electrophoregrams of rosemary extracts through their migration times and UV spectra obtained by CZE analysis of pure compounds isolated from a rosemary extract by HPLC fractionation. The CZE method had good reproducibility (relative standard deviation less than 5%) and was applied to compare the contents of carnosol and carnosic acid in solid and oil-dispersed commercial extracts of rosemary and in rosemary leaves. The separation of carnosol and carnosic acid was accomplished in less than 11 min.     

Bioactive clerodane diterpenes from roots of Carex distachya

Two new clerodane diterpenes were isolated from roots of Carex distachya Desf., a perennial plant widely distributed in the coastal area of the Mediterranean basin. Chemical characterization of the metabolites was carried out mainly by 1D and 2D NMR spectroscopy. The isolated compounds influenced either positively or negatively the plant growth (root and shoot elongation) of three coexisting herbaceous species.