Further antibacterial diterpenes from the bark and leaves ofJuniperus procera hochst. ex Endl

Isolation, characterization, and antimicrobial activity of communic acid from Juniperus phoenicea

OBJECTIVES

A mixture of Z and E communic acid is isolated for the first time from the cones of Juniperus phoenicea. Its biological activity was studied.

METHODS

The plant material was extracted in a Soxhlet apparatus with n-hexane, the resulting extract was subjected to column chromatography (CC) on silica gel. The structure elucidation of the constituents of the isolated fraction was identified by comparison of its spectroscopic properties ¹H and ¹³C NMR data with those reported in the literature. The antimicrobial assay of hexanic extract and isolated compounds was carried out by the disc diffusion and micro-dilution methods.

RESULTS

A mixture of two diterpene acids isomers was isolated, with a high yield (68%). Their chemical structures were confirmed after comparing their spectral data with published reports. These natural products exhibited a significant antibacterial and antifungal activity against the tested strains. Indeed, for Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa, the inhibition zone diameters (36-37 mm) was better than penicillin, novobiocin, and amoxicillin. For Candida albicans activity, it show that the mixture possess an activity similar to that of Metrazol. Against Escherichia coli, the inhibitory activity was found less than Amoxicillin. This is the first report of isolation of communic acid from J. phoenicea.

CONCLUSIONS

These results showed that the cones of J. phoenicea were an important source of communic acid, and its hexanic extract had the greatest potential antibacterial activity against both Gram-negative and Gram-positive bacteria and C. albicans.

Majra Honey Abrogated the Normal and Cancer Cells Proliferation Inhibition by Juniperus procera Extract and Extract/Honey Generated AgNPs

BACKGROUND

Juniperus procera and Majra honey are well-known as a folk medicine in many countries.

OBJECTIVES

This work aimed to study the immunomodulatory effects after mixing Majra honey, J. procera water leaves extract and silver Nanoparticles (AgNPs) on immune or cancer cells.

METHODS

Juniperus procera water leaves extract and 20% Majra honey were prepared. Both the extract and honey were used separately to synthesize AgNPs. AgNPs were characterized using UV/Vis spectrophotometry and electron microscopy. Bioactive molecules in honey and the extract were explored using Fourier Transform Infrared (FT-IR) spectroscopy. Protein profile of honey was explored using Sodium Dodecyl Sulfate- Polyacrylamide Gel Electrophoresis (SDS-PAGE) and honey sugar content was determined using High- Performance Liquid Chromatography (HPLC). Biological activities of honey and the extract were tested.

RESULTS

The results demonstrated the ability of the extract/honey to produce AgNPs in a spherical shape. The extract/honey contained many functional groups. SDS-PAGE of Majra honey showed many protein bands. HPLC revealed honey is of good quality and no external additives are added to it. The extract and extract+ AgNPs inhibited the growth of normal rat splenic cells while honey stimulated it. The extract+honey turned stimulatory to the splenic cells' growth and significantly diminished the inhibitory potential of the extract containing AgNPs. Both the extract and honey have antimicrobial activities, this potential increased in the presence of AgNPs. Honey and Honey+AgNPs inhibited HepG2 cancer cell proliferation while Hela cell growth inhibited only with honey+AgNPs.

CONCLUSION

Both honey and the extract have antibacterial and immunomodulatory potentials as well as the power to produce AgNPs. Majra honey alone showed anticancer activity against HepGe2 cells, but not against Hela cells, and when contained AgNPs had anticancer activity on both cell lines. Mixing of Majra honey with J. procera extract showed characterized immunomodulatory potentials that can be described as immunostimulant.

Taicrypnacids A and B, a Pair of C37 Heterodimeric Diterpenoid Stereoisomers from Taiwania cryptomerioides

Two uncommon C₃₇ heterodimeric diterpenoids, taicrypnacids A (1) and B (2), and a known labdane-type diterpenoid (3) were isolated from the leaves of Taiwania cryptomerioides. Several techniques, such as comprehensive spectroscopic analysis, chemical conversion, X-ray crystallography, and ECD data, were employed to define the structures. The two new compounds displayed cytotoxicity against human breast cancer (MCF-7), osteosarcoma (U-2 OS), and human colon carcinoma (HCT-116) cell lines, while the methyl ester 1a showed no activity. Compound 1 induced Ca²⁺-ROS pathway-mediated endoplasmic reticulum stress, and excessive stress led to cell death by activating apoptosis and autophagy.

Traditional use of ethnomedicinal native plants in the Kingdom of Saudi Arabia

The Arabian Peninsula is recognized as an arid area dominated by deserts and poor biodiversity. However, the Kingdom of Saudi Arabia (henceforth abbreviated into KSA) has a wide range of flora, consisting of different species of trees, herbs, and shrubs and containing numerous edible and medicinal plants. The KSA is characterized by its vast area of diverse geographical landscapes and climates. Consequently, there is enormous variation in the distribution of plants across the Kingdom. The traditional use of ethnomedical plants in the KSA represents a strong interconnection among familiar remedies, health, diet, and traditional healing practices characterized by specific cultures. The present paper reviews a collection of medicinal plants in KSA used in ethnomedicine. This review might be useful in developing strategies for the sustainable use of medicinal plants which are among the threatened important natural resources in folk medicine in the KSA. The present study reports 309 genera which cover 471 species from a total of 2253 known species belonging to 89 families. The most dominating families are Asteraceae, Fabaceae, Lamiaceae, Euphorbiaceae, Solanaceae, Apiaceae, Brassicaceae, Chenopodiaceae, Poaceae, Amaranthaceae, Boraginaceae, Apocynaceae, Convolvoulaceae, Asclepiadaceae, Capparaceae, Polygonaceae, and Zygophyllaceae.

Taiwanoids A-D, four dimeric diterpenoids featuring tetracyclic [7. 75, 9. 4. 05, 10. 08, 9] octodecane from Taiwania cryptomerioidesim

Biogenesis-inspired chemical research of the leaves of Taiwania cryptomerioides afforded four unprecedented dimeric diterpenes, featuring a tetracyclic [7. 75, 9. 4. 05, 10. 08, 9] octodecane core: taiwanoids A-D (1-4). The structures of these compounds were determined on the basis of comprehensive spectral analysis, chemical conversions and X-ray crystallography. A possible biosynthetic pathway for compounds 1-4 was proposed. Compounds 2 and 3 exerted a 5.37 and 6.26-fold potentiation effect on bortezmib (BTZ) susceptibility at a tested concentration of 20 μM, respectively.

Cellular proliferation/cytotoxicity and antimicrobial potentials of green synthesized silver nanoparticles (AgNPs) using Juniperus procera

Juniperus spp. are used as medicinal plants in many countries like Bosnia, Lebanon, and Turkey. In folk medicines, these plants have been used for treating skin and respiratory tract diseases, urinary problems, rheumatism and gall bladder stones. The objectives of this work were to synthesize silver nanoparticles (AgNPs) using a coniferous tree, Juniperus procera leaf extract and testing the synthesized AgNPs for its antimicrobial potentials, hemolytic activity, toxicity and the proliferative effects against normal and activated rat splenic cells. Leaf extract was prepared using acetone and ethanol as solvents. AgNPs were prepared using the acetone extract. AgNPs were validated using UV–Vis spectroscopy and scanning electron microscopy (SEM). Functional groups in the extract were identified using Fourier Transform Infrared (FT-IR) spectroscopy. SEM images of AgNPs showed spherical and cubic shapes with a uniform size distribution with an average size of 30–90 nm. FT-IR spectroscopy showed the presence of many functional groups in the plant extract. AgNPs showed promising antimicrobial activity against tested bacteria and fungus. AgNPs also expressed a stimulating activity towards the rat splenic cells in a dose dependent manner. Acetone as solvent was safer on cells than ethanol. Green synthesized AgNPs using J. procera might be used as a broad-spectrum therapeutic agent against microorganisms and as an immunostimulant agent.

Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K

Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression.

Preparative mass-spectrometry profiling of bioactive metabolites in Saudi-Arabian propolis fractionated by high-speed countercurrent chromatography and off-line atmospheric pressure chemical ionization mass-spectrometry injection

Propolis is a glue material collected by honeybees which is used to seal cracks in beehives and to protect the bee population from infections. Propolis resins have a long history in medicinal use as a natural remedy. The multiple biological properties are related to variations in their chemical compositions. Geographical settings and availability of plant sources are important factors for the occurrence of specific natural products in propolis. A propolis ethylacetate extract (800mg) from Saudi Arabia (Al-Baha region) was separated by preparative scale high-speed countercurrent chromatography (HSCCC) using a non-aqueous solvent system n-hexane-ACN (1:1, v/v). For multiple metabolite detection, the resulting HSCCC-fractions were sequentially injected off-line into an atmospheric pressure chemical ionization mass-spectrometry (APCI-MS/MS) device, and a reconstituted mass spectrometry profile of the preparative run was visualized by selected ion traces. Best ion-intensities for detected compounds were obtained in the negative APCI mode and monitored occurring co-elution effects. HSCCC and successive purification steps resulted in the isolation and characterization of various bioactive natural products such as (12E)- and (12Z)-communic acid, sandaracopimaric acid, (+)-ferruginol, (+)-totarol, and 3β-acetoxy-19(29)-taraxasten-20a-ol using EI-, APCI-MS and 1D/2D-NMR. Cycloartenol-derivatives and triterpene acetates were isolated in mixtures and elucidated by EI-MS and 1D-NMR. Free fatty acids, and two labdane fatty acid esters were identified by APCI-MS/MS. In total 19 metabolites have been identified. The novel combination of HSCCC fractionation, and APCI-MS-target-guided molecular mass profiling improve efficiency of lead-structure identification.

UPLC-MS-ELSD-PDA as a powerful dereplication tool to facilitate compound identification from small-molecule natural product libraries

The generation of natural product libraries containing column fractions, each with only a few small molecules, using a high-throughput, automated fractionation system, has made it possible to implement an improved dereplication strategy for selection and prioritization of leads in a natural product discovery program. Analysis of databased UPLC-MS-ELSD-PDA information of three leads from a biological screen employing the ependymoma cell line EphB2-EPD generated details on the possible structures of active compounds present. The procedure allows the rapid identification of known compounds and guides the isolation of unknown compounds of interest. Three previously known flavanone-type compounds, homoeriodictyol (1), hesperetin (2), and sterubin (3), were identified in a selected fraction derived from the leaves of Eriodictyon angustifolium. The lignan compound deoxypodophyllotoxin (8) was confirmed to be an active constituent in two lead fractions derived from the bark and leaves of Thuja occidentalis. In addition, two new but inactive labdane-type diterpenoids with an uncommon triol side chain were also identified as coexisting with deoxypodophyllotoxin in a lead fraction from the bark of T. occidentalis. Both diterpenoids were isolated in acetylated form, and their structures were determined as 14S,15-diacetoxy-13R-hydroxylabd-8(17)-en-19-oic acid (9) and 14R,15-diacetoxy-13S-hydroxylabd-8(17)-en-19-oic acid (10), respectively, by spectroscopic data interpretation and X-ray crystallography. This work demonstrates that a UPLC-MS-ELSD-PDA database produced during fractionation may be used as a powerful dereplication tool to facilitate compound identification from chromatographically tractable small-molecule natural product libraries.

Anti-mycobacterial natural products from the Canadian medicinal plant Juniperus communis

ETHNOPHARMACOLOGICAL RELEVANCE

Common juniper, Juniperus communis, is amongst the plants most frequently used by the indigenous peoples of North America for medicinal purposes. The First Nations of the Canadian Maritimes use infusions of juniper primarily as a tonic and for the treatment of tuberculosis. Previous investigations of extracts derived from the aerial parts of J. communis have shown it to possess anti-mycobacterial activity. The aim of the study is to isolate and identify anti-mycobacterial constituents from the aerial parts of J. communis.

MATERIALS AND METHODS

Methanolic extracts of J. communis needles and branches were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The anti-mycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

The diterpenes isocupressic acid and communic acid and the aryltetralin lignan deoxypodophyllotoxin were isolated from the J. communis extract. Isocupressic acid and communic acid (isolated as an inseparable 3:2 mixture of cis and trans isomers) displayed MICs of 78 μM and 31 μM and IC(50)s of 46 μM and 15 μM against M. tuberculosis H37Ra respectively. Deoxypodophyllotoxin was less active, with a MIC of 1004 μM and an IC(50) of 287 μM.

CONCLUSIONS

Isocupressic acid, communic acid and deoxypodophyllotoxin were identified as the principal constituents responsible for the anti-mycobacterial activity of the aerial parts of J. communis. Although further research will be required to evaluate the relative activities of the two communic acid isomers, this work validates an ethnopharmacological use of this plant by Canadian First Nations and Native American communities.

Communic acids: occurrence, properties and use as chirons for the synthesis of bioactive compounds

Communic acids are diterpenes with labdane skeletons found in many plant species, mainly conifers, predominating in the genus Juniperus (fam. Cupresaceae). In this review we briefly describe their distribution and different biological activities (anti- bacterial, antitumoral, hypolipidemic, relaxing smooth muscle, etc.). This paper also includes a detailed explanation of their use as chiral building blocks for the synthesis of bioactive natural products. Among other uses, communic acids have proven useful as chirons for the synthesis of quassinoids (formal), abietane antioxidants, ambrox and other perfume fixatives, podolactone herbicides, etc., featuring shorter and more efficient processes.

Pharmacological explanation for the medicinal use of Juniperus excelsa in hyperactive gastrointestinal and respiratory disorders

Crude extract of Juniperus excelsa (JeExt), which tested positive for the presence of anthraquinone, flavonoids, saponins, sterols, terpenes and tannin, exhibited a protective effect against castor oil-induced diarrhoea in mice at 100-1000 mg/kg. In rabbit jejunum preparations, JeExt (0.01-1.0 mg/mL) caused relaxation of spontaneous and K(+) (80 mM)-induced contractions at similar concentrations to papaverine, whereas verapamil was relatively more potent against K(+). JeExt (0.03-0.3 mg/mL) shifted Ca(2+) concentration-response curves to the right, like papaverine or verapamil. JeExt (0.003-0.01 mg/mL) caused a leftward shift of isoprenaline-induced inhibitory concentration-response curves, similar to papaverine. JeExt (1.0-30 mg/kg) caused suppression of carbachol (CCh, 100 μg/kg)-induced increase in inspiratory pressure of anaesthetized rats. In guinea-pig trachea, JeExt (0.001-3.0 mg/mL) relaxed CCh (1 μM)- and high K(+)-induced contractions and shifted isoprenaline-induced inhibitory curves to the left. This study suggests that Juniperus excelsa possibly exhibits a combination of Ca(2+) antagonist and phosphodiesterase inhibitory effects, which provides a pharmacological basis for its traditional use in disorders of gut and airways hyperactivity, such as diarrhoea, colic and asthma.

Antimycobacterial terpenoids from Juniperus communis L. (Cuppressaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Juniperus communis is a plant which has been reported as a traditional cure for tuberculosis (TB) and other respiratory diseases.

AIM OF THE STUDY

The aim of this study was to isolate and identify the constituents responsible for the activity of the n-hexane extract of Juniperus communis roots against Mycobacterium tuberculosis H(37)Rv and Juniperus communis aerial parts against Mycobacterium aurum. Subsequently, it was to evaluate the activity of the pure isolated compounds against (i) drug-resistant Mycobacterium tuberculosis variants, (ii) non-replicating Mycobacterium tuberculosis and (iii) a range of non-tuberculous mycobacteria (NTM).

MATERIALS AND METHODS

The antimycobacterial activity of Juniperus communis extracts, fractions and constituents was determined against Mycobacterium tuberculosis H(37)Rv, and against rifampicin-, isoniazid-, streptomycin- and moxifloxacin-resistant variants, using the microplate broth Alamar Blue assay (MABA) method. Isolated constituents were tested against non-replicating Mycobacterium tuberculosis H(37)Rv, using the low oxygen recovery assay (LORA), and against NTM (Mycobacterium aurum, Mycobacterium phlei, Mycobacterium fortuitum and Mycobacterium smegmatis), using a broth microdilution method. Cytotoxicity studies were performed using mammalian Vero cells.

RESULTS

The antimycobacterial activity of Juniperus communis was attributed to a sesquiterpene identified as longifolene (1) and two diterpenes, characterised as totarol (2) and trans-communic acid (3). All compounds were identified following analysis of their spectroscopic data (1D- and 2D-NMR, MS) and by comparison with the literature and commercial authentic standards when available. Revised assignments for 3 are reported. Totarol showed the best activity against Mycobacterium tuberculosis H(37)Rv (MIC of 73.7 microM). It was also most active against the isoniazid-, streptomycin-, and moxifloxacin-resistant variants (MIC of 38.4, 83.4 and 60 microM, respectively). Longifolene and totarol were most active against the rifampicin-resistant variant (MICs of 24 and 20.2 microM, respectively). Totarol showed the best activity in the LORA assay (MIC of 81.3 microM) and against all NTM species (MICs in the range of 7-14 microM). Trans-communic acid showed good activity against Mycobacterium aurum (MIC of 13.2 microM). The low selectivity indices (SI) obtained following cytotoxicity studies indicated that the isolated terpenoids were relatively toxic towards mammalian cells. This is the first report of the isolation of (1) and (2) from Juniperus communis roots, and of (3) from the aerial parts. The antimycobacterial activity of (1) and (3), and the activity of (2) against Mycobacterium aurum, Mycobacterium fortuitum and Mycobacterium phlei, is reported for the first time. The effect of totarol on drug-resistant variants and non-replicating Mycobacterium tuberculosis has never been published.

CONCLUSIONS

The presence of antimycobacterial terpenoids in Juniperus communis aerial parts and roots justifies, to some extent, the ethnomedicinal use of this species as a traditional anti-TB remedy.

Antiparasitic, nematicidal and antifouling constituents from Juniperus berries

A bioassay-guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta-7,13-diene (1) demonstrated in vitro antimalarial activity against Plasmodium falciparum D6 and W2 strains (IC(50) = 1.9 and 2.0 microg/mL, respectively), while totarol (6), ferruginol (7) and 7beta-hydroxyabieta-8,13-diene-11,12-dione (8) inhibited Leishmania donovani promastigotes with IC(50) values of 3.5-4.6 microg/mL. In addition, totarol demonstrated nematicidal and antifouling activities against Caenorhabditis elegans and Artemia salina at a concentration of 80 microg/mL and 1 microg/mL, respectively. The resinous exudate of J. virginiana afforded known antibacterial E-communic acid (4) and 4-epi-abietic acid (5), while the volatile oil from its trunk wood revealed large quantities of cedrol (9). Using GC/MS, the two known abietanes totarol (6) and ferruginol (7) were identified from the berries of J. procera, J. excelsa and J. phoenicea.

The chemical composition of hexane extract from bark of Juniperus brevifolia

The phytochemical analysis of the bark of Juniperus brevifolia was undertaken for the first time. The GC-MS analysis of the hexane extract from bark of "cedro-do-mato" (J. brevifolia) allowed to identify three rare compounds for the first time in Juniperus genus: 6,7-dehydroferrugin-12-methyl ether, 11-hydroxy-6,7-dehydroferruginol and 6,7-dehydrohinokiol. The results also showed that the chemical composition of the extract were essentially abietane-type diterpenoids with alcohol function (44.9%) and with carbonyl function (8.6%). Fatty acids such palmitic, oleic, stearic and docosanoic acids were the second most abundant family of identified compounds (9.5%) and its value increased (12.7%) after alkaline hydrolysis, mainly due to docosanoic and tetradocosanoic acids. Sterols like sitosterol and stigmast-4-en-3-one, were also present (6.6%), along with esters of sterols (8.4%). Significant quantities of the long-chain aliphatic alcohols (ca 3.7%) were identified in the hexane extract only after alkaline hydrolysis.

Diterpene constituents of leaves from Juniperus brevifolia

The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3beta-hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta-8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported (13)C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other diterpenoid compounds.

Sesquiterpenoids and cytotoxic lignans from the bark of Libocedrus chevalieri

Investigation of an EtOAc extract of the bark of Libocedrus chevalieri led to the isolation of a new cytotoxic lignan, 5-methoxy-4-epipodophyllotoxin (1), and three known podophyllotoxin analogues, 5-methoxypodophyllotoxin, 5-methoxypodophyllotoxin-4-O-beta-D-glucoside, and podophyllotoxin-4-O-beta-D-glucoside. Six sesquiterpenoids and a diterpenoid were also obtained. Of these, compounds 2-4 are new sesquiterpenoids, named libocedrines A-C, and 3beta-hydroxyilicic alcohol was isolated for the first time from a higher plant. Structures of the new compounds were determined on the basis of spectroscopic methods. Cytotoxicity of the isolated compounds against KB and L1210 cells and their effects on tubulin assembly were evaluated.

Antibacterials and modulators of bacterial resistance from the immature cones of Chamaecyparis lawsoniana

As part of an on-going project to characterize compounds from immature conifer cones with antibacterial or modulatory activity against multidrug-resistant (MDR) strains of Staphylococcus aureus, eight compounds were isolated from the cones of Chamaecyparis lawsoniana. The active compounds were mainly diterpenes, with minimum inhibitory concentrations ranging from 4 to 128 microg/ml against MDR effluxing S. aureus strains and two epidemic methicillin-resistant (EMRSA) clinical isolates. The compounds extracted were the diterpenes ferruginol, pisiferol and its epimer 5-epipisiferol, formosanoxide, trans-communic acid and torulosal, the sesquiterpene oplopanonyl acetate and the germacrane 4beta-hydroxygermacra-1(10)-5-diene. Some of these compounds also exhibited modulatory activity in potentiating antibiotic activity against effluxing strains and ferruginol, used at a sub-inhibitory concentration, resulted in an 80-fold potentiation of oxacillin activity against strain EMRSA-15. An efflux inhibition assay using an S. aureus strain possessing the MDR NorA efflux pump resulted in 40% inhibition of ethidium bromide efflux at 10 microM ferruginol (2.86 microg/ml). We report the (1)H and (13)C NMR data for the cis A/B ring junction epimer of pisiferol which we have named 5-epipisiferol. We also unambiguously assign all (1)H and (13)C NMR resonances for trans-communic acid.

Antineoplastic agents. 529. Isolation and structure of nootkastatins 1 and 2 from the Alaskan yellow cedar Chamaecyparis nootkatensis

The yellow cedar tree, Chamaecyparis nootkatensis, collected in southeast Alaska was evaluated as a potential source of new anticancer agents. Two new diterpene anticancer constituents termed nootkastatins 1 (4) and 2 (5) were isolated along with three previously known diterpene cancer cell growth inhibitors where two were reported as synthetic modifications of totarol and not previously found in nature. All five diterpene structures were established by HRMS and 1D and 2D NMR spectroscopic analyses combined with three X-ray crystal structure determinations (2, 3, and 5). Against a panel of six human cancer cell lines, this series of diterpenes exhibited inhibition over the range GI(50) 0.75-2.0 microg/mL, and all inhibited the growth of Gram-positive bacteria and fungi.

Antimycobacterial constituents fromJuniperus procera, Ferula communis andPlumbago zeylanica and theirin vitro synergistic activity with isonicotinic acid hydrazide

The synergistic activity of antimycobacterial constituents from Saudi plants was evaluated in combination with isonicotinic acid hydrazide (INH) against four atypical organisms, namely, Mycobacterium intracellulare, M. smegmatis, M. xenopei and M. chelonei. The potency of INH was increased four-fold, using an in vitro checkerboard method, against each mycobacteria when tested with a subtoxic concentration of the totarol, isolated from J. procera. The MIC values of totarol, ferulenol (from Ferula communis) and plumbagin (from Plumbago zeylanica) were thus lowered from 1.25-2.5 to 0.15-0.3 microg/mL due to synergism with INH. When tested against the resistant strain of M. tuberculosis H37Rv, plumbagin and 7beta-hydroxyabieta-8,13-dien-11,12-dione exhibited inhibitory activity at <12.5 microg/mL, while others were inactive at this concentration.

(+)-Totarol from Chamaecyparis nootkatensis and activity against Mycobacterium tuberculosis

The isolation of (+)-totarol as active compound against Mycobacterium tuberculosis is reported from Chamaecyparis nootkatensis outerbark.

The synthesis and antibacterial activity of totarol derivatives. Part 2: Modifications at C-12 and O-13

Alterations of the C-12 and C-13 aromatic ring substituents of totarol (1) afforded the series of derivatives 2-14, and introduction of substituents at C-12 gave exclusively 2a-14a. The majority of these analogues were tested in vitro against the following organisms: beta-lactamase-positive and high level gentamycin-resistant Enterococcus faecalis, penicillin-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA), and multiresistant Klebsiella pneumoniae. The results were evaluated in terms of structure-activity relationship which reveals that: (a) the phenolic moiety at C-13, in general, is essential for antibacterial activity at < 32 microg/mL against gram-positive species, and (b) derivatization at C-12 has an undesirable effect on the antibacterial activity of this class of compounds, while (c) all compounds tested are ineffective against the gram-negative Klebsiella pneumoniae.

The synthesis and antibacterial activity of totarol derivatives. Part 1: modifications of ring-C and pro-drugs

A series of analogues of, and potential pro-drugs derived from, the potent antibacterial diterpene totarol (1) were synthesized in order to elucidate the minimum structural requirements for antibacterial activity and to seek compounds with good bioavailability in vivo. These analogues varied in the structural features of their aromatic rings and the prodrugs were O-glycosylated derivatives. They were tested in vitro against three gram-positive bacteria: beta-lactamase-positive and high level gentamycin-resistant Enterococcus faecalis, penicillin-resistant Streptococcus pneumoniae, and methicillin-resistant Staphylococcus aureus (MRSA); and against the gram-negative multi-drug-resistant Klebsiella pneumoniae. None of the analogues was more potent than totarol itself, which is effective against these gram-positive bacteria at MIC values of 7 microM. The results were evaluated in terms of a structure-activity relationship and this showed that a phenolic moiety was essential for potent antibacterial activity. Amongst the pro-drugs, totaryl alpha-D-mannopyranoside (22) proved the most active in vitro (MIC 18 microM). The in vivo antibacterial activities of compounds 1, 22 and totarol beta-lactoside (23) were assessed in a mouse model of infection, but they were found to be ineffective. Compounds 1 and 22 were shown to be cytotoxic towards proliferating human cell cultures, CH 2983, HeLa, and MG 63, but only at concentrations of > 30 microM.