Chemical Composition of the Essential Oils of the Iberian Peninsula Endemic Species Eryngium dilatatum Lam.

Eryngium dilatatum Lam. is a thorny Iberian Peninsula endemic species belonging to the Apiaceae family that has not been previously analysed from a chemical point of view. Following our studies on this genus, we characterized the chemical composition of the essential oils from the different parts (inflorescences, stems + leaves, and roots) of this species; these parts were gathered in Cádiz (Spain). The specimens were collected in July during the flowering period and air-dried before the oil extraction by hydro-distillation. The essential oils were analysed by gas chromatography and gas chromatography coupled with mass spectrometry. The different parts of the plant yielded low amounts of pale yellow oil, with the roots being the fraction that provided the lowest amount of oil. The chemical characterization of the essential oils showed qualitative and quantitative differences between the fractions examined, but all of them showed the same principal compound, germacrene D (9.1-46.5%). Similarly, all the fractions shared most of their representative constituents, with their percentage compositions being different from one sample to the other: α-cadinol (3.8%), bicyclogermacrene (3.5%), octanal (3.1%), and spathulenol (2.5%) were found in the inflorescences; octanal (8.1%), α-cadinol (3.7%), δ-cadinene (3.6%), (E)-caryophyllene (2.6%), bicyclogermacrene (2.5%), and spathulenol (2.4%) were found in the stems and leaves; and spathulenol (4.6%), α-cadinol (4.4%), khusinol (3.2%), α-muurolol (3.1%), and δ-cadinene (2.6%) were found in the roots. As far as we know, this is the first report about the chemical composition of this endemic species of the Iberian Peninsula. It contributes to the knowledge of this species and to the genus to which it belongs. This species could be considered as a natural source of germacrene D, which is a sesquiterpene hydrocarbon with active properties.

Review of the Leaf Essential Oils of the Genus Backhousia Sens. Lat. and a Report on the Leaf Essential Oils of B. gundarara and B. tetraptera.

A review of the leaf oils of the 13 species now recognised in the genus Backhousia is presented. This review carries on from, and incorporates data from, an earlier (1995) review of the then recognised eight species. The leaf oils of two new species of Backhousia, B. gundarara and B. tetraptera are reported for the first time. B. gundarara contains a mixture of mono- and sesquiterpenes, with α-pinene (14%) and spathulenol (11%) being the main members. In B. tetraptera, the principal component of the mainly terpenoid leaf oil is myrtenyl acetate (20-40%). The review also incorporates the two species of the genus Choricarpia, which have been subsumed into Backhousia, viz. B. leptopetala and B. subargentea. Due to its history in Backhousia, Syzygium anisatum, which has been transferred out of Backhousia, is included in the review for historical reasons.

The Essential Oil Composition of Trachymene incisa Rudge subsp. incisa Rudge from Australia.

Trachymene incisa subsp. incisa is an Australian endemic taxon that varies greatly in the abundance and length of the leaf trichomes. The essential oil composition of five populations of this subspecies, three corresponding to the typical glabrous form and two of the particularly hairy variant, has been analyzed in an attempt to determinate if that variability is also reflected in their composition. The oils have been extracted by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography coupled to Mass Spectrometry (GC-MS). The essential oils of T. incisa subsp. incisa were characterized by the high amount of sesquiterpenes that were the major fraction. The sesquiterepene hydrocarbons were significantly higher in the hairy variant in comparison to the glabrous one. According to the main compound, three different chemotypes were found: I.-ß-selinene + bicyclogermacrene and II.-γ-bisabolene + α-pinene for the typical glabrous variant and III.-bicyclogermacrene + ß-caryophyllene for the hairy variant.

Phytochemical Profile and Antibacterial and Antioxidant Activities of Medicinal Plants Used by Aboriginal People of New South Wales, Australia.

Aboriginal people of Australia possess a rich knowledge on the use of medicinal plants for the treatment of sores, wounds, and skin infections, ailments which impose a high global disease burden and require effective treatments. The antibacterial and antioxidant activities and phytochemical contents of extracts, obtained from eight medicinal plants used by Aboriginal people of New South Wales, Australia, for the treatment of skin related ailments, were assessed to add value to and provide an evidence-base for their traditional uses. Extracts of Acacia implexa, Acacia falcata, Cassytha glabella, Eucalyptus haemastoma, Smilax glyciphylla, Sterculia quadrifida, and Syncarpia glomulifera were evaluated. All extracts except that of S. quadrifida showed activity against sensitive and multidrug resistant strains of Staphylococcus aureus with minimum inhibitory concentration values ranging from 7.81 to 1000 µg/mL. The sap of E. haemastoma and bark of A. implexa possessed high total phenolic contents (TPC) and strong DPPH radical scavenging abilities. A positive correlation was observed between TPC and free radical scavenging ability. GC-MS analysis of the n-hexane extract of S. glomulifera identified known antimicrobial compounds. Together, these results support the traditional uses of the examined plants for the treatment of skin related ailments and infections by Aboriginal people of New South Wales, Australia.

Coconut Laurels: The Leaf Essential Oils from Four Endemic Australian Cryptocarya Species: C. bellendenkerana, C. cocosoides, C. cunninghamii and C. lividula (Lauraceae).

The leaf oils of four species of Cryptocarya, endemic to Australia, were examined. These species are known colloquially as 'coconut laurels' due to the purported distinctive aroma from the crushed foliage. C. cocosoides produced an oil in which bicyclogermacrene (3-26%), spathulenol (16-47%), massoia lactone (6-pentyl-5,6-dihydro-2H-pyran-2-one) (11-15%), (6-heptyl-5,6-dihydro-2H-pyran-2-one (0.3-3%) and benzyl benzoate (0.2-5%) were the principal components. C. cunninghamii showed a second chemotype to that previously published, with benzyl benzoate (80.2%) being the principal component. C. bellendenkerana gave a leaf oil in which the major components were the terpenes limonene (8.3%), ß-phellandrene (11.8%) and viridiflorene (9.1%). The principal components of the leaf oil of C. lividula were bicyclogermacrene (26.1%), spathulenol (21.1%) and ß-eudesmol (6.1%). Benzaldehyde and acetophenone were both present in amounts of less than 0.7%. Only C. cocosoides and C. cunninghamii have been found to have a 'coconut' aroma mainly due to the presence of massoia lactone and homologues.

Antimicrobial and antioxidant activity and chemical characterisation of Erythrina stricta Roxb. (Fabaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: The bark of Erythrina stricta Roxb. (Fabaceae) has been used in Indian indigenous systems as a remedy for rheumatism, stomach-ache, asthma, dysentery, contact dermatitis, eczema and skin infections. However, there have been limited phytochemical or biological studies on the bark of E. stricta and there are no studies that align with its traditional medicinal uses. AIM OF THE STUDY: The aim of this study was to assess the antimicrobial and antioxidant activity of the stem bark of E. stricta to support its topical use in the treatment of contact dermatitis, eczema and skin infections and to isolate and identify any bioactive compounds. MATERIALS AND METHODS: MTT microdilution and disc diffusion assays were used to determine the antimicrobial activities of n-hexane, dichloromethane, ethyl acetate, methanol and water extracts of the bark of E. stricta. Column and preparative thin layer chromatography were used for the purification of the dichloromethane extract. The structures of the compounds isolated were elucidated by extensive 1D and 2D NMR spectroscopic techniques and comparison with published data. The antioxidant activities of the extracts were determined by DPPH free radical scavenging and FRAP assays and the antioxidant activity of the pure compounds by dot-blot and DPPH staining methods. RESULTS: The dichloromethane, ethyl acetate, and n-hexane extracts showed the most significant activity with MIC values of 7.8µg/mL, 125µg/mL, and 125µg/mL against a sensitive strain of Staphylococcus aureus. The dichloromethane and ethyl acetate extracts also showed significant activity against Candida albicans with MIC values of 125µg/mL and 1mg/mL respectively. GC-MS analysis of the n-hexane extract showed the presence of the antibacterial and antifungal compounds ß-caryophyllene, caryophyllene oxide, α-selinene, ß-selinene, selin-11-en-4-α-ol, α-copaene and δ-cadenine. Phytochemical studies of the dichloromethane extract led to the isolation of the novel compound erynone (1), together with six known compounds; wighteone (2), alpinum isoflavone (3), luteone (4), obovatin (5), erythrinassinate B (6) and isovanillin (7). Luteone (4) exhibited the most significant antibacterial activity with minimum inhibitory quantity (MIQ) values of 1.88µg, 1.88µg and 3.75µg, respectively, against sensitive (MSSA) and resistant strains (MRSA and MDRSA) of S. aureus using a TLC bioautography assay. Erynone (1) exhibited the greatest DPPH free radical scavenging activity. CONCLUSIONS: Seven compounds, including a new chromanone, were isolated from the antimicrobial dichloromethane extract of the stem bark of E. stricta. Six of the seven compounds showed antibacterial and/or antioxidant activities. These findings provide support for the customary (traditional and contemporary) use of E. stricta bark for the treatment of skin and wound infections.

Bioactivity and chemical characterisation of Lophostemon suaveolens--an endemic Australian Aboriginal traditional medicinal plant.

Lophostemon suaveolens is a relatively unexplored endemic medicinal plant of Australia. Extracts of fresh leaves of L. suaveolens obtained from sequential extraction with n-hexane and dichloromethane exhibited antibacterial activity in the disc diffusion and MTT microdilution assays against Streptococcus pyogenes and methicillin sensitive and resistant strains of Staphylococcus aureus (minimum bactericidal concentration < 63 µg/mL). The dichloromethane extract and chromatographic fractions therein inhibited nitric oxide in RAW264.7 murine macrophages (IC50 3.7-11.6 µg/mL) and also PGE2 in 3T3 murine fibroblasts (IC50 2.8-19.7 µg/mL). The crude n-hexane, dichloromethane and water extracts of the leaves and chromatographic fractions from the dichloromethane extract also showed modest antioxidant activity in the ORAC assay. GC-MS analysis of the n-hexane fraction showed the presence of the antibacterial compounds aromadendrene, spathulenol, ß-caryophyllene, α-humulene and α-pinene and the anti-inflammatory compounds ß-caryophyllene and spathulenol. Fractionation of the dichloromethane extract led to the isolation of eucalyptin and the known anti-inflammatory compound betulinic acid.

The Leaf Essential Oil of Eugenia reinwardtiana Growing in Australia.

The leaf essential oils of the two chemotypes of Eugenia reinwardtiana (Blume) DC growing in Australia have been investigated. Chemotype 1, isolated in 0.2% yield, w/w, dry weight, contained major amounts of α-pinene (10-26%), limonene (1-15%), ß-caryophyllene (0.7-11%), α-humulene (0.9-16%) and bicyclogermacrene (1-23%). The second chemotype, found only on coastal dunes SW of Lockerbie Qld, and isolated in 0.4-0.6% (w/w, dry weight), contained α-pinene (tr-8.5%) ß-caryophyllene (12-27%) and α-humulene (1-17%) as the major terpenes. This chemotype also contained the novel aliphatic diketone, 2-butyl-2,4,4-trimethyl-5-methoxycyclohex-5-en-1,3-dione (18-33%), whose structure determination is reported herein.

Essential oil composition of the different parts of Eryngium aquifolium from Spain.

The essential oils from the different parts [inflorescences (E.a.I), stems + leaves (E.a.SL) and roots (E.a.R)] of E. aquifolium Cav. gathered in Cádiz (Spain), have been extracted by steam distillation and analyzed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative and qualitative differences have been found between the analyzed plant parts. A total of 107 compounds have been identified. The main constituents were germacrene D (30.3%) and sesquicineole (26.7%) for E.a.I fraction, germacrene D (46.0%) and myrcene (13.8%) in the E.a.SL, while E.a.R showed phyllocladene isomer (63.6%) as a unique major compound. The percentage composition of the other constituents was lower than 5.5% in all the analyzed fractions. In agreement with other Eryngium species, no specific compound could be used as a marker for the chemotaxonomy of E. aquifolium. However, similarities in volatile composition were found between E. aquifolium and other species growing under similar environmental conditions. As far as we know, this is the first report on the essential oil of this species.

Essential oil composition of three Australian endemic species of Darwinia (Myrtaceae).

The essential oils from the aerial parts of three rare Australian endemic species of Darwinia have been extracted by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). In D. procera, myrtenyl acetate (6.1-29.6%), alpha-pinene (6.9-25.1%), gamma-terpinene (6.2-13.6%), bicyclogermacrene (5.5-10.8%) and (E)-nerolidol (3.4-9.7%) were the principal components detected. D. fascicularis ssp. fascicularis produced an oil in which (E)-nerolidol (33.0%), alpha-pinene (15.1%) and gamma-terpinene (10.2%) were the principal components. In D. peduncularis the major constituents were alpha-pinene (33.5%), gamma-terpinene (23.1%) and bicyclogermacrene (6.7%).

Essential oil composition of two new species of Phebalium (Rutaceae) from north-eastern NSW, Australia.

The composition of the essential oil steam distilled with cohobation from the aerial parts of two new undescribed species of Phelabium, P. stellatum I. Telford & J.J. Bruhl ined. and P. sylvaticum I. Telford & J.J. Bruhl ined., has been analyzed by gas chromatography and gas chromatography coupled to mass spectrometry. Both species were found to have a similar chemical composition. The essential oil of P. stellatum was characterized by high amounts of elemol (24.6-30.8%), beta-phellandrene (5.2-10.8%), beta-eudesmol (6.1-10.0%), hedycaryol (4.5-9.8%), and delta-3-carene (4.4-13.7%). The main compounds of the samples of P. sylvaticum were identified as myrcene (10.6-23.0%), elemol (11.3-14.6%), beta-phellandrene (0.5-14.8%), delta-3-carene (8.0-11.5%), beta-eudesmol (6.7-9.1%), hedycaryol (7.4-9.7%) and alpha-pinene (7.1-8.9%). This is the first report of the volatile components of these two new species.

Essential oil composition of the different parts of Eryngium corniculatum Lam. (Apiaceae) from Spain.

The essential oil from the different parts (inflorescences, stems+leaves and roots) of E. corniculatum Lam. gathered in Guadalajara (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative and qualitative differences have been found between the analysed parts, although all of them contained the same principal compound, 2,4,6-trimethylbenzaldehyde, representing the 50.8%, 50.0%, and 29.8% of the total oil for inflorescences, stems+leaves and roots, respectively. Other representative constituents of the oil were similar in the different fractions: in the inflorescences compounds were found to be alpha-pinene (4.0%), chrysanthenyl acetate (4.0%), 2,4,5-trimethylbenzaldehyde (3.3%), (2Z,6E)-farnesol (2.0%), (E)-nerolidol (2.1%) and (Z)-beta-ocimene (2.1%), while the stems+leaves oil showed 2,4,5-trimethylbenzaldehyde (3.8%), alpha-pinene (3.4%), (E)-nerolidol (2.4%) and (2Z,6E)-farnesol (2.1%), and in the roots oil a phyllocladene isomer (13.0%), (E)-nerolidol (9.4%), beta-eudesmol (4.1%) and (2Z,6E)-farnesol (2.1%) were found. The presence of C-10 compounds as the main fraction for an Eryngium species is worth mentioning. This is the first report on the chemical composition of this Mediterranean endemic species.

Triumphalone, a diketone from the volatile oil of the leaves of Melaleuca triumphalis, and its spontaneous conversion into isotriumphalone.

The major component (35-65%) of the volatile oil obtained by steam distillation of the leaves of Melaleuca triumphalis has been identified as (rel)-1beta-pentyl-1alpha,6alpha-dihydroxy-3,3,5,5-tetramethylcyclohexa-2,4-dione (trivial name triumphalone). Relative stereochemistry was established by nuclear Overhauser experiments and X-ray studies on the 2-(3,5-dinitrobenzoic acid) derivative. The remainder of the oil was composed of mono- and sesquiterpene hydrocarbons and alcohols. On prolonged standing the presence of a rearrangement product of triumphalone was observed which was characterized as (rel)-1beta-pentyl-1alpha,3alpha-dihydroxy-4,4,6,6-tetramethylcyclohexa-2,5-dione (trivial name isotriumphalone), presumably arising from an acid catalyzed shift of the pentyl group from C-1 to C-2.

Analysis of the essential oil composition from the different parts of Eryngiumglaciale Boiss. from Spain.

The essential oil from the different parts (inflorescences, stems + leaves and roots) of Eryngium glaciale Boiss. gathered in Sierra Nevada (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene isomer (43.5%), (E)-caryophyllene (15.2%) and valencene (11.5%), while the oil from stems and leaves only showed phyllocladene isomer (41.3%) as main one. The oil from the roots presented phyllocladene isomer (49.4%) and linalool (19.1%) as major constituents. This is the first report on the chemical composition of this species.

Indole alkaloids from the leaves of Philippine Alstonia scholaris.

The first seco-uleine alkaloids, manilamine (1) (18-hydroxy-19,20-dehydro-7,21-seco-uleine) and N4-methyl angustilobine B (2), were isolated from the (pH 5) alkaloid extract of Philippine Alstonia scholaris leaves together with the known indole alkaloids 19,20-(E)-vallesamine (3), angustilobine B N4-oxide (4), 20(S)-tubotaiwine (5), and 6,7-seco-angustilobine B (6). The structure of the alkaloids was established from MS and NMR experiments.

Essential oil composition of the different parts of Eryngium bourgatii Gouan from Spain.

The essential oil extracted from the different parts of Eryngium bourgatii Gouan: stems + leaves (E.b.SL), inflorescences (E.b.I) and roots (E.b.R), have been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene (37.6%) and bicyclogermacrene (15.1%), while the oil from stems and leaves showed phyllocladene (20.4%), gamma-muurolene (11.8%) and (E)-caryophyllene (10.1%) as main ones. The oil from the roots presented gamma-muurolene (15.4%) and phyllocladene (15.0%) as major constituents. It is worth mentioning the presence of a diterpene, phyllocladene, as main compound of the essential oil. This is the first report on the essential oil of this species.

Antiherbivore chemistry of Eucalyptus-cues and deterrents for marsupial folivores.

Formylated phloroglucinol compounds (FPCs) are the single most important factor determining the amount of foliage that marsupial folivores eat from individual Eucalyptus trees. Folivores need to recognize which trees contain FPCs if they are to avoid them and forage efficiently, they are challenged by great diversity in the types and quantities of FPCs present, even within eucalypt species. We investigated the relationship between FPCs and terpenoids in species with both simple and complex FPC profiles and found strong positive correlations between terpenes generally, and several monoterpenes in particular, and FPCs. Terpene cues also indicated qualitative differences in trees' FPC profiles. We describe significant qualitative and quantitative variation in FPCs in several species that are important food sources for marsupial folivores. New discoveries include the fact that macrocarpals occur as two major, distinct groups and several new dimeric acylphloroglucinols from Eucalyptus strzeleckii. These patterns add to the chemical complexity of the foraging environment for folivores.