Volume 58, Issue 9-10

New and known structural and functional insights in the role of β-carotene and of α- tocopherol in photosytem II are reviewed. A concept is presented connecting the failure of P680 triplet quenching by β-carotene with the formation of singlet oxygen and its scavenging in the turnover of the D1 protein and by tocopherol in the maintenance of PS II structure and function.

The pentacyclic triterpenes rhoiptelenol and rhoiptelenone have been isolated from Sideritis macrostachya. Rhoiptelenone is a new natural compound, whose structure has been determined as D:B-friedo-urs-5-en-3-one. The 1H and 13 C NMR spectra of rhoiptelenol, rhoiptelenol acetate and glutinol have been reassigned. The natural occurrence of the D:B-friedoursene and D:B-friedo-oleanene derivatives has been examined.

Four known tropane alkaloids were isolated from the leaves of the endemic Chilean plant Latua pubiflora (Solanaceae). For the first time; 3α-cinnamoyloxitropane and apoatropine are reported in this plant. Scopolamine and hyoscyamine were previously reported.

The chemical composition of the extracted fixed oil (total fatty acid composition) and volatile oil of Nigella sativa L. seeds grown in Iran were determined by GC and GC/MS. Eight fatty acids (99.5%) and thirty- two compounds (86.7%) have been identified in the fixed and volatile oils, respectively. The main fatty acids of the fixed oil were linoleic acid (55.6%), oleic acid (23.4%), and palmitic acid (12.5%). The major compounds of the volatile oil were trans-anethole (38.3%), p-cymene (14.8%), limonene (4.3%), and carvone (4.0%).

From the underground parts of Thalictrum orientale Boiss., a new phenolic compound 1 was isolated in addition to one known cyanoglycoside, lithospermoside (2). For the structure elucidation of all compounds, 1D- and 2D-NMR techniques (DEPT, COSY, HMBC, HSQC) and MS (HR-MALDI) were used. The structure of the new compound was established as 2-(4′-hydroxyphenyl)-nitroethane-4′-O-[β-xylopyranosyl-(1→6)-β-glucopyranoside] (1).

Besides caffeic acid three pyrones have been isolated from aquous bark extracts from Acosmium panamense and their structures were determined using spectroscopical methods. Besides the already described desmethylyangonine its O 4′ -mono as well as the di(1-6)glucoside are found the first time.

Two compounds, (p-methoxyphenyl) diphenylmethanol (1) and tribenzylamine (2), were isolated from Humulus lupulus. Their structures were established on the basis of spectral evidence (MS, IR, NMR, HMBC, HMQC, 1 H- 1 H COSY experiments). Compounds 1 and 2 were found as natural products at the first time.

The floral resin of Tovomitopsis saldanhae (Guttiferae) is composed of poliisoprenylated benzophenone and the major constituent is 7-epi-nemorosone which has now been revised.

The leaves of Tillandsia brachycaulos afforded two novel tetracyclic triterpenoids identified as (24S)-24-isopropenyl-29-nor-5α-lanosta-7-en-3β-ol (1) and (24S)-24-isopropenyl-29-nor- 5α-lanosta-7-en-3-one (2), in addition to the known isopimaric acid (3) and chlorogenic acid (4). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC) and by comparison with data in the literature. The antimicrobial and antifungal activities were studied. The compounds did not show significant activity.

Hyperfoliatin, a new polyisoprenylated phloroglucinol derivative was isolated from the aerial parts of Hypericum perfoliatum (Clusiaceae) collected in Algeria. The structure of hyperfoliatin was elucidated on the basis of its spectral data, mainly MS and multiple-pulse NMR.

A new natural pyridine derivative (3-aldehyde-2-amino-6-methoxypyridine, 1) together with (R)-glycidyl octadecanoate (2) and five ergostane-type sterols (3-7) were isolated from the fruiting bodies of the basidiomycete Cortinarius umidicola Kauffm. Their structures were established by spectral methods (MS, IR, 1D and 2D-NMR experiments).

From the methanolextract of Penicillium sp. cultivated on sterilized rice for three weeks we isolated three new meroterpenes preaustinoid A1, A2 and B1. The fungus was isolated from the root bark of Melia azedarach after surface sterilization. The structures of these compounds were identified by intensive spectroscopic studies.

Geraniin and gallic acid were isolated from the alcohol extract of the aerial parts of Erodium glaucophyllum (Geraniaceae). The identity of the compounds was verified through different physical and spectrometric methods. The antibacterial and antifungal activity of geraniin is presented.

Amburana cearensis a common tree found in Northeastern Brazil is widely used in folk medicine. The present work evaluated the cytotoxicity of kaempferol, isokaempferide, amburoside A and protocatechuic acid isolated from the ethanol extract of the trunk bark of A. cearensis. The compounds were tested for their cytotoxicity on the sea urchin egg development, hemolysis assay and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay using tumor cell lines. Isokaempferide and kaempferol, but not amburoside A and protocatechuic acid, inhibited the sea urchin egg development as well as tumor cell lines, but in this assay isokaempferide was more potent than kaempferol. Protocatechuic acid was the only compound able to induce hemolysis of mouse erythrocytes, suggesting that the cytotoxicity of kaempferol and isokaempeferide was not related to membrane damage.

Essential oils of Nepeta parnassica, collected at different developmental stages, were analyzed by means of GC/MS. From the fifty-five identified constituents in samples A and B, representing 94.8% and 98.7% of the oils respectively, 4aα,7α,7aβ-nepetalactone (22.0%), 1,8-cineole (21.1%), α-pinene (9.5%) and 4aα,7β,7aβ-nepetalactone (7.9%) were the major components of sample A (vegetative stage), whereas in sample B (flowering stage) the main contributors were 1,8-cineole (34.6%), 4aα,7α,7aα-nepetalactone (17.3%), α-pinene (11.4%) and 4aα,7α,7aβ-nepetalactone (8.9%). The oils were tested on human health important insects such as the Pogonomyrmex sp. ants and the Culex pipiens molestus mosquitoes with promising results on insect repellency/toxicity.

The water-distilled essential oil the leaves of Coridothymus capitatus were analyzed by GC/MS and also analyzed by direct thermal desorption GC/MS. Comparison was made between two analyses techniques. The essential oil consisted mainly of monoterpenes 98.9%, while oxygenated hydrocarbons were identified as 55.6% and non-oxygenated hydrocarbons as 43.6%. As major components were found carvacrol (35.6%), p-cymene (21.0%), thymol (18.6%), γ-terpinene (12.3%), α-terpinene (3.2%), β-myrcene (3.0%) and α-thujene (1.3%) by hydrodistillation and by the GC/MS method. The direct thermal desorption GC/MS analysis also showed the same major components, namely carvacrol (51.6%), thymol (21.7%), pcymene (9.7%) γ-terpinene (8.2%), α-terpinene (1.64%). The essential oil of C. capitatus showed strong activity against S. aureus, P. vulgaris, P. aeruginosa, E. coli, K. pneumonia, B. subtilis, E. faecalis, S. epidermidis and C. albicans.

A simple stereoselective synthesis of montroumarin [(3S)-6,8-dihydroxy-3-phenyl-3,4-dihydroisocoumarin] isolated from Montrouziera sphaeroidea has been achieved. Condensation of benzoyl chloride with 3,5-dimethoxyhomophthalic acid afforded 6,8-dimethoxy-3-phenylisocoumarin (3) which on sequential saponification and esterification yielded the keto ester 5. Enantioselective reduction of the latter with baker’s yeast directly furnished the (3S)-6,8- dimethoxy-3-phenyl-3,4-dihydroisocoumarin (6) in good enantioselectivity which on demethylation provided montroumarin. All of the synthesized compounds were examined in vitro for antifungal activity.

Sterols, triterpenes, volatiles, polar and other constituents in aerial parts of Carthamus lanatus were analyzed by gas chromatography-mass spectrometry. Over 90 compounds were identified most of them new for the species. Sitosterol and stigmasterol were the most abundant of 10 sterols identified in the sterol fraction. Taraxasterol, α- and β-amyrine prevailed in the triterpene fraction. Volatiles, sterols and a fraction of the dichloromethane extract showed strong cytotoxicity (Artemia salina assay).

Two flavonoid aglycons, eight flavonoid glycosides, chlorogenic acid and syringin were isolated from aerial parts of Carthamus lanatus. Isorhamnetin 3-O-β-ᴅ-glucoside and chlorogenic acid were found for the first time in the genus Carthamus and respectively, quercimeritrin, astragalin, kaempferol 3-O-β-ᴅ-sophoroside and syringin in the species. The ethyl acetate fraction of the methanol extract exhibited a higher antioxidant activity than the butanol fraction measured by the α,α-diphenyl-β-picrazylhydrazyl (DPPH) free radical scavenging assay. Cytotoxicity and antioxidant activities of the main constituent, luteolin 7-O-β-D-glucoside, were evaluated.

It was the objective of the present study to increase the production of glucoamylase by Aspergillus awamori through solid state fermentation, using wheat bran as the main carbon source and (NH 4 ) 2 SO 4 , urea, KH 2 PO 4 , glucose, maltose and starch as additional nitrogen, phosphorus, and carbon sources. The production of glucoamylase is strongly influenced by N and C sources. A 100% increase was observed when the (NH 4 ) 2 SO 4 was replaced by urea, with C/N = 4.8, using maltose as the additional carbon source. C/P ratios in a range of 5.1 to 28.7 did not induce glucoamylase production under the studied conditions.

Anisic acid (p-methoxybenzoic acid) was characterized as a tyrosinase inhibitor from aniseed, a common food spice. It inhibited the oxidation of l-3,4-dihydroxyphenylalanine (ʟ- DOPA) catalyzed by tyrosinase with an IC 50 of 0.60 mᴍ. The inhibition of tyrosinase by anisic acid is a reversible reaction with residual enzyme activity. This phenolic acid was found to be a classical noncompetitive inhibitor and the inhibition constant K I was obtained as 0.603 mᴍ. Anisic acid also inhibited the hydroxylation of ʟ-tyrosine catalyzed by tyrosinase. The lag phase caused by the monophenolase activity was lengthened and the steady-state activity of the enzyme was decreased by anisic acid.

As a defense mechanism of the leaves of Rhus javanica (Anacardiaceae) against the aphid Melaphis chinensis (Aphididae) attack, tannic acid is rapidly accumulated and forms galls along the midrib of the leaves resulting in a unique natural medicine Gallae Rhois. Tannic acid was found to inhibit the oxidation of ʟ-3,4-dihydroxyphenylalanine (ʟ-DOPA) catalyzed by tyrosinase (EC 1.14.18.1) with an IC 50 of 22 μᴍ. The aphid would detoxify the ingested toxic tannic acid to relatively nontoxic gallic acid, whereas the non-adapted pink bollworm Pectinophora gossypiella larvae are sensitive to the ingested tannic acid.

Naphthalene degradation by freely suspended and immobilized cells of Pseudomonas sp. isolated from contaminated effluents has been investigated in batch cultures and continuously in a packed bed reactor. Naphthalene concentration was varied from 25 mᴍ to 75 mᴍ, the temperature (30 °C) and pH (7.0) were kept constant. The results showed good acclimation of the strain to carbon source and degradation rate was highly affected by initial concentration. Alginate-entrapped cells have given good yields although initial rates were not as high as those encountered with free cells. A first order exponential decay kinetic model was proposed with values of parameters for each initial concentration. A laboratory scale packedbed bioreactor was designed using parameters calculated above and continuous experiments were realized at different flow rates (100 to 200 ml/h), with different feed concentrations and operating during 30 days. The conversion at low feed concentrations and low flow rates was complete whereas at high flow rates and high concentrations it was less efficient because of diffusional limitations and short residence time.

Mouse erythroleukemic F4 N cells were treated with mimosine, etoposide, Fe(II)-EDTA, and Cu(II) in the presence of ascorbate. DNA was isolated and subjected to agarose gel electrophoresis and the size and distribution of the DNA fragments produced by the agents were compared. With increasing concentration of Cu(II) the production of DNA fragments was increased without decrease of the average length of the fragments, and their sizes were similar to those produced by etoposide as expected for cleavage of DNA at the nuclear matrix attachments sites. In contrast, mimosine and Fe(II) produced fragments of random size and with the progression of the reaction the average length of the fragments decreased. These results indicate that mimosine cuts DNA in a random fashion, regardless of its higher order chromatin organization. A conclusion is drawn that the DNA fragments obtained after mimosine treatment are a result of mimosine-assisted, Fe(II) dependent Fenton-like reactions randomly cutting chromosomal DNA.

GRP94 (glucose regulated protein 94) gene expression in the ischemic-hippocampus of gerbils, which was induced by a temporary occlusion of the bilateral common carotid arteries (CCAs), was tested by Northern blot analysis. The maximum GRP94 gene expression level was detected at the occipital lobe 10 min after the induction of ischemia. In the hippocampus, GRP94 gene expression reached a maximum 15 min after inducing ischemia. Following reperfusion, the maximum expression level was shown at 12 h and continuing thereafter.

A new cyclotetrapeptide 1, together with three known cyclopeptides were isolated from the exo-cellular extract of Pseudomonas sp. a bacterium associated with the sponge Ircinia muscarum. The structure of 1 was suggested on the basis of spectroscopic analytical data and chemical degradation.

The production of antimicrobial compounds by fungi associated with Clusia spp. pollinating bees (Trigona sp., Trigonini) was investigated in order to approach natural mechanisms of microbial density control within nest environment. By using a bioassay-guided approach based on bioautography and minimal inhibitory concentration (MIC), known α,β-dehydrocurvularin and curvularin were isolated from Curvularia eragrostidis (CCT 5634) and Curvularia pallescens (CCT 5654), and known cochlioquinone A and isocochlioquinone A were isolated from Drechslera dematioidea (CCT 5631).

Recent investigations of scrapie, Creutzfeldt-Jakob disease (CJD), and chronic wasting disease (CWD) clusters in Iceland, Slovakia and Colorado, respectively, have indicated that the soil in these regions is low in copper and higher in manganese, and it has been well-known that patients of ALS or Parkinson’s disease were collectively found in the New Guinea and Papua islands, where the subterranean water (drinking water) contains much Al 3+ and Mn 2+ ions. Above facts suggest that these neurodegenerative diseases are closely related with the function of a metal ion. We have investigated the chemical functions of the metal ions in detail and established the unique mechanism of the oxygen activation by the transition metal ions such as iron and copper, and pointed out the notable difference in the mechanism among iron, aluminum and manganese ions. Based on these results, it has become apparent that the incorporation of Al(III) or Mn(II) in the cells induces the “iron-overload syndrome”, which is mainly due to the difference in an oxygen activation mechanism between the iron ion and Al(III) or the Mn(II) ion. This syndrome highly promotes formation of hydrogen peroxide, and hydrogen peroxide thus produced can be a main factor to cause serious damages to DNA and proteins (oxidative stress), yielding a copper(II)-or manganese(II)-peptide complex and its peroxide adduct, which are the serious agents to induce the structural changes from the normal prion protein (PrP C ) to abnormal disease-causing isoforms, PrP Sc , or the formation of PrP 27Ð30 (abnormal cleavage at site 90 of the prion protein). It seems reasonable to consider that the essential origin for the transmissible spongiform encephalopathies (TSEs) should be the incorporation and accumulation of Al(III) and Mn(II) ions in the cells, and the sudden and explosive increase of scrapie and bovine spongiform encephalopathy (BSE) in the last decade may be partially due to “acid rain”, because the acid rain makes Al(III) and Mn(II) ions soluble in the subterranean aquifers.

A new sweet dihydrochalcone-glucoside, trilobatin 2″- acetate (1), was isolated from the leaves of Lithocarpus pachyphyllus, together with phlorizin and trilobatin. The structures were established by spectroscopic methods, including one- and two-dimensional NMR (COSY, HMQC and HMBC).

The quantitative determination of flavonoid compounds in flowers and leaves of Ficaria verna Huds. (Ranunculaceae) was carried out in different growing seasons of the plant, using Christ-Müller’s method (Polish Pharmacopoeia, 1999) and high performance liquid chromatography (HPLC) analysis after acid hydrolysis. The flavonoid content was much higher in flowers than in leaves.