César A.N. Catalán

Comparative study of chemical composition and antioxidant activity of fresh and dry rhizomes of turmeric (Curcuma longa Linn.).

The phytoconstituents of essential oil and ethanol oleoresin of fresh and dry rhizomes of turmeric (Curcuma longa Linn.) were analyzed by GC-MS. The major constituents were aromatic-turmerone (24.4%), alpha-turmerone (20.5%) and beta-turmerone (11.1%) in fresh rhizome and aromatic-turmerone (21.4%), alpha-santalene (7.2%) and aromatic-curcumene (6.6%) in dry rhizome oil. Whereas, in oleoresins, the major components were alpha-turmerone (53.4%), beta-turmerone (18.1%) and aromatic-turmerone (6.2%) in fresh and aromatic-turmerone (9.6%), alpha-santalene (7.8%) and alpha-turmerone (6.5%) in dry rhizome. Results showed that alpha-turmerone, a major component in fresh rhizomes is only minor one in dry rhizomes. Also, the content of beta-turmerone in dry rhizomes is less than a half amount found in fresh rhizomes. The antioxidant properties have been assessed by various lipid peroxidation assays as well as DPPH radical scavenging and metal chelating methods. The essential oil and ethanol oleoresin of fresh rhizomes have higher antioxidant properties as compared dry ones.

Hypoglycemic activity of leaf organic extracts from Smallanthus sonchifolius: Constituents of the most active fractions.

The aim of the present study was to determine the in vivo hypoglycemic activity of five organic extracts and enhydrin obtained from yacon leaves. The main constituents of the most active fraction were identified. Five organic extracts and pure crystalline enhydrin were administered to normoglycemic, transiently hyperglycemic and streptozotocin (STZ)-diabetic rats. The fasting and post-prandial blood glucose, and serum insulin levels were estimated and an oral glucose tolerance test (OGTT) was performed for the evaluation of hypoglycemic activity and dose optimization of each extract. We found that the methanol, butanol and chloroform extracts showed effective hypoglycemic activity at minimum doses of 50, 10 and 20mg/kg body weight, respectively, and were selected for further experiments. Oral administration of a single-dose of each extract produced a slight lowering effect in the fasting blood glucose level of normal healthy rats, whereas each extract tempered significantly the hyperglycemic peak after food ingestion. Daily administration of each extract for 8 weeks produced an effective glycemic control in diabetic animals with an increase in the plasma insulin level. Phytochemical analysis of the most active fraction, the butanol extract, showed that caffeic, chlorogenic and three dicaffeoilquinic acids were significant components. Additionally, enhydrin, the major sesquiterpene lactone of yacon leaves, was also effective to reduce post-prandial glucose and useful in the treatment of diabetic animals (minimum dose: 0.8mg/kg body weight). The results presented here strongly support the notion that the phenolic compounds above as well as enhydrin are important hypoglycemic principles of yacon leaves that could ameliorate the diabetic state.

Biosynthetic studies of marine lipids—3 : Experimental demonstration of the course of side chain extension in marine sterols

Abstract The Pacific sponge Aplysina fistularis was fed cholesterol-[4- 14 C],(24 R )-methyl-25-dehydrocholesterol-[26- 14 C] (epicodisterol[26- 14 C]), (24 S )-methyl-25-dehydrocholesterol-[26- 14 C] (codisterol-[26- 14 C]), and 24-methylenecholesterol-[28- 14 C]. Only epicodisterol, which has the same stereochemistry at C-24 as (24 R ,25 S )-24,26-dimethylcholesterol (aplysterol), was converted with high efficiency into (24 R )-24,27-dimethyl-25-dehydrocholesterol (25-dehydroaplysterol). Further side chain extension [to E -(24 R )-24,26,27-trimethyl-25-dehydrocholesterol (verongulasterol)] could also be demonstrated.

Species diversity and toxigenic potential of Fusarium graminearum complex isolates from maize fields in northwest Argentina.

Members of the Fusarium graminearum species complex (Fg complex) are the causal agents of ear rot in maize and Fusarium head blight of wheat and other small grain cereals. The potential of these pathogens to contaminate cereals with trichothecene mycotoxins is a health risk for both humans and animals. A survey of ear rot isolates from maize collected in northwest Argentina recovered 66 isolates belonging to the Fg complex. A multilocus genotyping (MLGT) assay for determination of Fg complex species and trichothecene chemotypes was used to identify 56 of these isolates as F. meridionale and 10 isolates as F. boothii. F. meridionale was fixed for the nivalenol (NIV) chemotype, and all of the F. boothii isolates had the 15-acetyldeoxynivalenol (15ADON) chemotype. The results of genetic diversity analysis based on nine variable number tandem repeat (VNTR) loci supported the hypothesis of genetic isolation between F. meridionale and F. boothii, and provided little evidence of geographic substructure among populations of the dominant pathogen species, F. meridionale. This is the first study to indicate that F. meridionale and F. boothii may play a substantial role in the infection and trichothecene contamination of maize in Argentina. In addition, dominance of the NIV chemotype among Fg complex isolates from Argentina is unprecedented, and of significant concern to food safety and animal production.

A linear sesterterpene, two squalene derivatives and two peptide derivatives from Croton hieronymi.

Aerial parts of Croton hieronymi furnished in addition to a large number of plant sterols and triterpenes the C-25 analog of trans-phytol, the squalene derivatives all-trans-2,6,15,19,23-pentamethyltetracosa-2,6,10,(28),14,22,28-hexaene-11-ol and all-trans-10-methylene-2,6,10,14,18,22-pentamethyltetracosa-1,6,10,14,18,22-hexaen-3-ol, the sesquiterpenes epicubenol and T-cadinol, the acetophenone derivative xanthoxylin and the peptide derivatives aurentiamide acetate and N-benzoylphenylalanyl-N-benzoylphenylalaninate.

Composition, In Vitro Antioxidant and Antimicrobial Activities of Essential Oil and Oleoresins Obtained from Black Cumin Seeds (Nigella sativa L.)

Gas chromatography-mass spectrometry (GC-MS) analysis revealed the major components in black cumin essential oils which were thymoquinone (37.6%) followed by p-cymene (31.2%), α-thujene (5.6%), thymohydroquinone (3.4%), and longifolene (2.0%), whereas the oleoresins extracted in different solvents contain linoleic acid as a major component. The antioxidant activity of essential oil and oleoresins was evaluated against linseed oil system at 200 ppm concentration by peroxide value, thiobarbituric acid value, ferric thiocyanate, ferrous ion chelating activity, and 1,1-diphenyl-2-picrylhydrazyl radical scavenging methods. The essential oil and ethyl acetate oleoresin were found to be better than synthetic antioxidants. The total phenol contents (gallic acid equivalents, mg GAE per g) in black cumin essential oil, ethyl acetate, ethanol, and n-hexane oleoresins were calculated as 11.47 ± 0.05, 10.88 ± 0.9, 9.68 ± 0.06, and 8.33 ± 0.01, respectively, by Folin-Ciocalteau method. The essential oil showed up to 90% zone inhibition against Fusarium moniliforme in inverted petri plate method. Using agar well diffusion method for evaluating antibacterial activity, the essential oil was found to be highly effective against Gram-positive bacteria.

GLAUCOLIDES, HIRSUTINOLIDES AND OTHER SESQUITERPENE LACTONES FROM VERNONANTHURA PINGUIS

Aerial parts of Vernonanthura pinguis contained nine known and five new glaucolides, two known and five new hirsutinolides, two new 1-deoxyhirsutinolides, one vernomargolide analogue and one eudesmanolide. The possibility that the hirsutinolides are artifacts of the isolation procedure is discussed.

Piptocarphols and other constituents of Chrysolaena verbascifolia and Lessingianthus rubricaulis

Abstract Extraction of the aerial parts of Chrysolaena verbascifolia afforded a number of new piptocarphols (hirsutinolides), two new cadinanolides, two rare lignans and several common plant constituents, while the aerial parts of Lessingianthus rubricaulis furnished a new cadinanolide, vomifoliol and several triterpenes. Structures were established by high resolution NMR spectrometry. The possibility that the isolated sesquiterpene lactones are artefacts formed during the isolation process is discussed.

Glaucolides and related sesquiterpene lactones from Vernonia nudiflora and Chrysolaena propinqua

Abstract Aerial parts of Vernonia nudiflora furnished glaucolides A and B, one known and one new glaucolide derivative, one known and three new hirsutinolide derivatives and two new cadinanolides as well as several flavonoids and other common plant constituents. Aerial parts of Chrysolaena propinqua gave glaucolide B, one known and one new hirsutinolide and common plant constituents.

Effect of biosynthetic intermediates and citrate on the phenyllactic and hydroxyphenyllactic acids production by Lactobacillus plantarum CRL 778

Aim:  To evaluate the influence of biosynthetic precursors, intermediates and electron acceptors on the production of antifungal compounds [phenyllactic acid (PLA) and hydroxyphenyllactic acid (OH‐PLA)] by Lactobacillus plantarum CRL 778, a strain isolated from home‐made sourdough.