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.

Ianthellamide A, a selective kynurenine-3-hydroxylase inhibitor from the Australian marine sponge Ianthella quadrangulata.

Ianthellamide A (1), a novel octopamine derivative, was isolated from the Australian marine sponge Ianthella quadrangulata. Compound 1 selectively inhibited the activity of kynurenine 3-hydroxylase with an IC(50) value of 1.5 µM. It also significantly increased the level of endogenous kynurenic acid in rat brain and hence has the potential as a neuroprotective agent in the treatment of neurodegenerative disorders.

Eusynstyelamides A, B, and C, nNOS inhibitors, from the ascidian Eusynstyela latericius.

Eusynstyelamides A-C (1-3) were isolated from the Great Barrier Reef ascidian Eusynstyela latericius, together with the known metabolites homarine and trigonelline. The structures of 1-3, with relative configurations, were elucidated by interpretation of their spectroscopic data (NMR, MS, UV, IR, and CD). The NMR data of 1 were found to be virtually identical to that reported for eusynstyelamide (4), isolated from E. misakiensis, indicating that a revision of the structure of 4 is needed. Eusynstyelamides A-C exhibited inhibitory activity against neuronal nitric oxide synthase (nNOS), with IC(50) values of 41.7, 4.3, and 5.8 microM, respectively, whereas they were found to be nontoxic toward the three human tumor cell lines MCF-7 (breast), SF-268 (CNS), and H-460 (lung). Compounds 1 and 2 displayed mild inhibitory activity toward Staphylococcus aureus (IC(50) 5.6 and 6.5 mM, respectively) and mild inhibitory activity toward the C(4) plant regulatory enzyme pyruvate phosphate dikinase (PPDK) (IC(50) values of 19 and 20 mM, respectively).

A new rearranged dolabellane diterpene from the soft coral Clavularia inflata.

A new dolabellane type diterpene 1 has been isolated through its acetate 1a. The structure of 1a was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry. The structure of 1 was deduced by comparison of its NMR spectral data with those of 1a, while its relative stereochemistry was deduced by NOESY. The absolute stereochemistry of C-7 was determined by analyses of 1 separately esterified with R and S O-mandelic acids.

A marine verticillane diterpenoid from Cespitularia erecta.

The dichloromethane extract of Cespitularia erecta afforded a new verticillane diterpenoid (1) and sarcophytol A (2) by silica gel chromatography. The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy.

Nordehydrocyclodercitin, a hexacyclic pyridoacridine alkaloid from the marine ascidian, Aplidium sp.

A new hexacyclic pyridoacridine alkaloid, nordehydrocyclodercitin (1), from an ascidian, Aplidium sp., cf. Aplidium cratiferum collected at Arab Reef, Great Barrier Reef, Australia is reported. Nordehydrocyclodercitin is structurally related to stellettamine (2) and cyclodercitin (3), which are sponge metabolites, and cycloshermilamine D (4) which was isolated from the marine tunicate Cystodytes violatinctus. The structure of nordehydrocyclodercitin was determined by interpretation of spectroscopic data, particularly those obtained from HMBC correlations, and by comparison with reported data for known related pyridoacridine alkaloids.

New xenicanes from Xenia viridis.

The dichloromethane extract of Xenia viridis afforded two new xenicane diterpenoids (3 and 4) by silica gel chromatography. The oxirane ring of 3 was found to be susceptible to a slow ring opening under acidic conditions to afford 5. Their structures were elucidated by extensive 1D and 2D NMR spectroscopy.

Effects of dietary leucine supplementation on exercise performance.

Branched chain amino acids (BCAA), particularly leucine, have been suggested to be ergogenic for both endurance and strength/power performance. This study investigated the effects of dietary leucine supplementation on the exercise performance of outrigger canoeists. Thirteen (ten female, three male) competitive outrigger canoeists [aged 31.6 (2.2) year, VO(2max) 47.1 (2.0) ml kg(-1) min(-1)] underwent testing before and after 6-week supplementation with either capsulated L: -leucine (45 mg kg(-1) d(-1); n = 6) or placebo (cornflour; n = 7). Testing included anthropometry, 10 s upper body power and work and a row to exhaustion at 70-75% maximal aerobic power where perceived exertion (RPE), heart rate (HR) and plasma BCAA and tryptophan concentrations were assessed. Leucine supplementation resulted in significant increases in plasma leucine and total BCAA concentrations. Upper body power and work significantly increased in both groups after supplementation but power was significantly greater after leucine supplementation compared to the placebo [6.7 (0.7) v. 6.0 (0.7) W kg(-1)]. Rowing time significantly increased [77.6 (6.3)-88.3 (7.3) min] and average RPE significantly decreased [14.5 (1.5)-12.9 (1.4)] with leucine supplementation while these variables were unchanged with the placebo. Leucine supplementation had no effect on the plasma tryptophan to BCAA ratio, HR or anthropometric variables. Six weeks' dietary leucine supplementation significantly improved endurance performance and upper body power in outrigger canoeists without significant change in the plasma ratio of tryptophan to BCAA.

Lihouidine, a novel spiro polycyclic aromatic alkaloid from the marine sponge Suberea n. sp. (Aplysinellidae, Verongida).

An investigation of a new species of sponge from the genus Suberea collected at Lihou Reef in the Coral Sea afforded lihouidine, an unprecedented cytotoxic spiro nonacyclic polyaromatic alkaloid. The structure of the alkaloid, which was racemic, was determined by a combination of 1D and 2D NMR techniques and single-crystal X-ray structural analysis.

Studies of Australian Ascidians. 5. Virenamides A-C, New Cytotoxic Linear Peptides from the Colonial Didemnid Ascidian Diplosoma virens.

Three new linear cytotoxic tripeptides, virenamides A-C have been isolated from extracts of the Didemnid ascidian Diplosoma virens collected on the Great Barrier Reef, Australia. Their structures were deduced from 1D and 2D NMR spectral data and confirmed by HPLC analysis of the constituent amino acids after hydrolysis of the peptides and derivatization with 1-fluoro-2,4-dinitrophen-5-yl-L-alanine amide using Marfey's procedure.