A Comprehensive Review on Chemotaxonomic and Phytochemical Aspects of Homoisoflavonoids,as Rare Flavonoid Derivatives

Homoisoflavonoids (3-benzylidene-4-chromanones) are considered as an infrequent flavonoid class, possessing multi-beneficial bioactivities. The present study gives an overview on phytochemical aspects of homoisoflavonoids, including utilized plant species, parts, extracts, and separation techniques. Overall, these compounds have mainly been isolated and identified from bulbs and rhizomes of the plants belonging to Asparagaceae and Fabaceae families, particularly the genera of Ophiopogon, Dracaena, Scilla, Polygonatum, and Caesalpinia.     

Multivariate analysis of the correlation between noctuidae subfamilies and the chemical structure of their sex pheromones or male attractants

Female-emitted pheromones and sex attractants of Noctuidae were investigated using a specific computer procedure to analyze data collected from the literature. Correspondence analysis was used to survey the structure-activity relationships of sex pheromones in seven subfamilies. Structural, stereochemical, and functional features of active molecules were related to taxonomy. This multidimensional analysis revealed that the prevalent chemical frame of noctuid moth pheromones was a monounsaturated acetate withZ stereochemistry and a double bond on the fifth carbon closest to the nonfunctional branch of the molecule. Possible phylogenetic relationships within Noctuidae and between Noctuidae and other families are discussed in light of the sex pheromone biochemistry. Female sex pheromones appeared to be an additional character to be considered in the classification of noctuid moths.     

γ-Linolenic and stearidonic acids in Mongolian Boraginaceae

Seeds of nine Central Asian species of Boraginaceae were investigated for the first time for their oil content and for the fatty acid composition of their seed oils by capillary gas chromatography. Levels of γ-linolenic acid ranged from 6.6 to 13.0% and levels of stearidonic acid ranged from 2.4 to 21.4% of total seed fatty acids. The seed oil ofHackelia deflexa exhibited the highest stearidonic acid content (21.4%) that has been found so far in nature. Other high contents of this fatty acid were in threeLappula species (17.2 to 18.1%). Seed oils ofCynoglossum divaricatum andAmblynotus rupestris contain considerable amounts ofcis-11-eicosenoic (5.3 to 5.8%) andcis-13-docosenoic acid (7.0 to 9.7%) besides γ-linolenic (10.2 to 13.0%) and stearidonic acid (2.4 to 6.5%), which distinguish these oils from those of other Boraginaceae genera. This paper was presented as a poster at 10th Minisymposium and Workshop on Plant Lipids, Sept. 3–6, 1995, in Berne, Switzerland.     

Species-specific composition of free amino acids on the leaf surface of fourSenecio species

The specificity of the chemical composition of the leaf surface of fourSenecio species was studied in order to understand the host selection ofTyria jacobaeae, a monophagous moth that hasSenecio jacobaea as its principal host plant. Pyrrolizidine alkaloids characteristic forSenecio species were not detected in water and sulfuric acid extracts of the leaf surface ofSenecio jacobaea. Water extracts of the leaf surfaces ofS. jacobaea, S. vulgaris, S. viscosus, andS. sylvaticus contained low concentrations of free amino acids. The proportions of these amino acids were very different from those inside the leaf tissues. In a discriminant analysis, the four species could be completely separated on the basis of the relative proportions of amino acids on the leaf surface.     

CHARACTERIZATION OF BREWING YEAST STRAINS BY NUMERICAL ANALYSIS OF TOTAL SOLUBLE CELL PROTEIN PATTERNS

Total soluble cell proteins from 33 yeast strains from the brewing industry were extracted and subjected to polyacrylamide gel electrophoresis. Yeast strains were grouped by computerized numerical analysis of protein banding patterns. Three clusters were obtained at r>0.90. Cluster I contained 21 Saccharomyces cerevisiae lager beer strains. Cluster II comprised two strains isolated from beer with a phenolic off flavour and a third strain used for lager beer brewing. Cluster III consisted of two bottom ale yeasts. Protein patterns of yeast strains within each cluster corresponded closely or were identical. However, the intensity of certain bands often varied and the number of peaks recorded was not identical. These minor differences were reproducible and regarded as characteristic for the specific strains. Protein patterns can therefore be used to characterize or fingerprint individual yeast strains.     

The use of glucosinolates for cultivar identification in swede,Brassica napus L var napobmssica (L) peterm

A quantitative study of the glucosinolates in the seed, cortex and medulla (peeled root) from nine cultivars (cvs) of swede, Brassica napus L var napobrassica (L) Peterm using high performance liquid chromatography was undertaken to see whether such characteristics could be used as a biochemical index of cultivar identity. All nine cultivars could be distinguished following an analysis of medulla glucosinolates, but the analysis of seed and cortex glucosinolates yielded no such useful information.     

Cuticular hydrocarbons and defensive compounds ofReticulitermes flavipes (Kollar) andR. santonensis (feytaud): Polymorphism and chemotaxonomy

Colonies ofReticulitermes flavipes andR. santonensis were collected from the southeastern United States (Georgia) and the southwest of France (Charente-maritime). Defensive compounds and cuticular hydrocarbons were identified by gas chromatography-mass spectrometry and quantified by gas chromatography using an internal standard for each caste and all colonies. These analyses show that although the cuticular hydrocarbons ofR. santonensis in Europe andR. flavipes in Georgia are identical, their relative proportions are different. However, the defensive compounds synthesized by their soldiers are different. A strong chemical polymorphism between sympatric colonies ofR. flavipes in the SW United States was detected in terms of both the hydrocarbons of the workers and soldiers and in the defensive secretions of the soldiers. The six defensive secretion phenotypes are based on the presence or absence of terpenes whereas the cuticular hydrocarbon phenotypes are based on significant differences in the proportions of the various components. A multivariate analysis (analysis of principal components) clearly permitted discrimination of four phenotypes (three inR. flavipes and one inR. santonensis) without intermediates. The hydrocarbons responsible for these variations were identified, and it was shown that the variations are neither seasonal nor geographic. The phenotypes of the cuticular hydrocarbons (workers and soldiers) and defensive compounds are linked in each colony, forming in three groups inR. flavipes Georgia, one subdivided into four subgroups according to the defensive secretion phenotypes. The role of these polymorphisms is discussed and ethological tests indicate that the chemical polymorphism do not determine aggressive behavior. The taxonomic significance of these results is considered and two hypothesis are formulated: (1) We only detected a strong genetic polymorphism in one unique species, and we believe thatR. santonensis was introduced into Europe in the last century from oneR. flavipes colony. (2) Chemical variability characterizes the sibling species that can be grouped into the same subspeciesR. flavipes. Unknown mechanisms of reproductive isolation separate them.     

The Chemistry of Exploding Ants, Camponotus SPP. (Cylindricus COMPLEX)

A detailed comparative analysis of the exocrine chemistry of nine Bruneian Camponotus species in the cylindricus complex is reported. Workers of these species are known to have hypertrophied mandibular glands and release their glandular contents suicidally from the head by rupturing the intersegmental membrane of the gaster. All of the species produce mixtures of polyacetate-derived aromatics, including hydroxyacetophenones, which display pH-dependent color changes, and aliphatic hydrocarbons and alcohols. In addition, three species contained (6R)-2,6-dimethyl-(2E)-octen-1,8-dioic acid (9) or (3S)-8-hydroxycitro-nellic acid (10a), previously unreported from insects. These compounds were characterized from their spectral data, and confirmed by comparison with synthetic samples. The allomonal role of these compounds is based on numerous field observations, and their chemotaxonomic value is presented.     

The Venom Alkaloids from Some African Monomorium Species

A comparative analysis of the venom alkaloids of 13 species of ants in the genus Monomorium collected in Africa was undertaken. Ants were collected in Kenya and South Africa. Most species produced 2,5-dialkylpyrrolidines and some of their analogous 1-pyrrolines. No alkaloids were detected in two species. M. robustior and M. macrops. Additionally, a novel 2-alkyl-1-pyrroline, whose structure was established by synthesis, was detected in M. notulum. This compound and others like it may serve as biosynthetic precursors for the formation of the 2,5-dialkylpyrrolidines found in many Myrmicine ant species.     

Oil Content and Fatty Acid Composition of Seeds of Guizotia Cass (Compositae)

Seeds of Guizotia abyssinica and wild Guizotia were analysed for oil content and fatty acid composition by multisequential and gas chromatographic methods, respectively. The oil content of G abyssinica ranged from 416 to 436 g kg^-1 (weight per kg dry matter of seeds) and that of the wild Guizotia taxa from 214 to 328 g kg^-1. Two unsaturated fatty acids (linoleic (54·3–72·8, weight percent of total oil) and oleic (5·4–26·8% of oil by wt) and two saturated fatty acids (palmitic (7·8–10%) and stearic (5·5–8·1%)) were about 91–97% of the fatty acids present. Palmitoleic, linolenic, arachidic, eicosenoic, behenic, erucic and lignoceric acids constituted about 2–3%. An unidentified fatty acid, probably an epoxy form of C: 20 or C: 22, has been found in all the materials and it was 1·1–6·6%. Total saturated and unsaturated fatty acids were about 74–84% and 15–20%, respectively. Differentiation in fatty acid composition between the taxa is too small to be of taxonomic use. It is inferred that when gene transfer is desired hybridisation between the wild and cultivated taxa may not affect the oil quality of the latter and the oils of the wild taxa are possibly safe for human consumption. © 1997 SCI.