A new HPLC-ELSD method to quantify indican in Polygonum tinctorium L. and to evaluate beta-glucosidase hydrolysis of indican for indigo production.

A method to quantify the indigo precursor indican (indoxyl-beta-D-glucoside) in Polygonum tinctorium L. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native beta-glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond beta-glucosidase and Novarom G preparation, were compared with P. tinctorium native beta-glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond beta-glucosidase <or= Novarom G

A new HPLC-ELSD method to quantify indican in Polygonum tinctorium L. and to evaluate beta-glucosidase hydrolysis of indican for indigo production.

A method to quantify the indigo precursor indican (indoxyl-beta-D-glucoside) in Polygonum tinctorium L. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native beta-glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond beta-glucosidase and Novarom G preparation, were compared with P. tinctorium native beta-glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond beta-glucosidas

Can volatile organic metabolites be used to simultaneously assess microbial and mite contamination level in cereal grains and coffee beans?

A novel approach based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-ToFMS) was developed for the simultaneous screening of microbial and mite contamination level in cereals and coffee beans. The proposed approach emerges as a powerful tool for the rapid assessment of the microbial contamination level (ca. 70 min versus ca. 72 to 120 h for bacteria and fungi, respectively, using conventional plate counts), and mite contamination (ca. 70 min versus ca. 24 h). A full-factorial design was performed for optimization of the SPME experimental parameters. The methodology was applied to three types of rice (rough, brown, and white rice), oat, wheat, and green and roasted coffee beans. Simultaneously, microbiological analysis of the samples (total aerobic microorganisms, moulds, and yeasts) was performed by conventional plate counts. A set of 54 volatile markers was selected among all the compounds detected by GC×GC-ToFMS. Principal Component Analysis (PCA) was applied in order to establish a relationship between potential volatile markers and the level of microbial contamination. Methylbenzene, 3-octanone, 2-nonanone, 2-methyl-3-pentanol, 1-octen-3-ol, and 2-hexanone were associated to samples with higher microbial contamination level, especially in rough rice. Moreover, oat exhibited a high GC peak area of 2-hydroxy-6-methylbenzaldehyde, a sexual and alarm pheromone for adult mites, which in the other matrices appeared as a trace component. The number of mites detected in oat grains was correlated to the GC peak area of the pheromone. The HS-SPME/GC×GC-ToFMS methodology can be regarded as the basis for the development of a rapid and versatile method that can be applied in industry to the simultaneous assessment the level of microbiological contamination and for detection of mites in cereals grains and coffee beans

Seasonal variation of indigo precursors in Isatis tinctoria L. and Polygonum tinctorium Ait. as affected by water deficit

In order to identify new crops suitable for indigo production in Italy, seasonal variation in productivity of indigo precursors was studied in woad (Isatis tinctoria L., Family Cruciferae) and in dyer’s knotweed (Polygonum tinctorium Ait., Family Polygonaceae), grown in central Italy under temperate climate. Indigo precursors, indoxyl-3-ketogluconate (isatan B) and indoxyl-β-D-glucoside (indican), were measured in leaves by HPLC analysis under well watered versus rain fed field conditions, and the amount of indigo derived by stoichiometric calculations. Woad showed lower indigo potential than dyer’s knotweed, evaluated as either amount of indigo either per leaf weight or per plant. However, in water stress conditions, woad appeared to be drought tolerant as opposed to dyer’s knotweed revealed very sensitive. In fact, in dyer’s knotweed leaf yield was over 50% reduced in water stress field conditions, characterizing central and southern Italy during July and August, as compared to some 30% in woad. Dyer’s knotweed appears to be more productive, providing water is supplied appropriately, thus making proper irrigation plans necessary to achieve sustainable high yields

Volatile compounds from three cultivars of Olea europaea from Italy

The chemical compositions of the volatile fractions from three Olea europaea L. cultivars (Leccino, Frantoio, and Cipressino) were examined by GC and GC-MS. The results showed that the cultivars can be distinguished on the basis of the volatile fraction composition

VASODILATOR ACTIVITY OF MICHELIA FIGO SPRENG (MAGNOLIACEAE) BY IN VITRO FUNCTIONAL STUDY

The methanolic extract of leaves of Michelia figo Spreng. (Magnoliaceae), as well as several purified fractions, showed a concentration-dependent vasorelaxing effect on aortic rings endothelium-deprived and pre-contracted by norepinephrine (NE). For further pharmacological investigation on the mechanism of action, the fraction S4 was selected, since it showed the best vasodilator properties. The pharmacological effect was not produced through the stimulation of cyclooxygenase, adenyl cyclase, or guanylyl cyclase, since selective inhibitors did not prevent the fraction S4-induced effects. Moreover, the vasorelaxing effect of the fraction was resistant to the block of nifedipine-sensitive Ca2+ channels. The fraction S4 (10(-4) g/ml) produced a shift towards the right of the concentration-contractile response curve to NE, in normal conditions, and the shift was more evident in Ca2+-free Tyrode Solution, Suggesting an action on intracellular Ca2+-channels. The vasodilator action of fraction S4 on NE pre-contracted rings was not prevented by cyclopiazonic acid (blocker of Ca2+/ATPase), which excludes a role for mechanisms involving the storage of Ca2+ in the sarcoplasmic reticulum. The reduction of the contraction elicited by caffeine, an opener of ryanodine-sensitive receptors suggests that the fraction S4 of Michelia figo leaves could produce the vasorelaxing response by the blockade of ryanodine-sensitive Ca2+ channels of the sarcoplasmic reticulum. (C) 2004 Elsevier Ireland Ltd. All rights reserved

Flavonoids analysis of four Vicia species of Narbonensis complex in two different vegetative phases

A qualitative analysis of flavonoids has been carried out for Vicia eristalioides Maxt., V. kalakhensis Khatt., Maxt. and Bisby, V. narbonensis L. and V. galilaea Plitm. et Zoh in two different vegetative phases. Free aglycones were consistently absent and there was no evidence of flavone glycosides, whereas kaempferol and quercetin glycosides were present in different amounts, according to the species. The flavonoid patterns of the four species were compared and differences were present among them and also within the same species during the two vegetative phases. The results indicate that flavonoid data may be used in the study of the organisation and evolution in Narbonensis comple