Pectic enzymes as potential enhancers of ascorbic acid production through the D-galacturonate pathway in Solanaceae

The increase of L-Ascorbic Acid (AsA) content in tomato (Solanum lycopersicum) is a common goal in breeding programs due to its beneficial effect on human health. To shed light into the regulation of fruit AsA content, we exploited a Solanum pennellii introgression line (IL12-4-SL) harbouring one quantitative trait locus that increases the content of total AsA in the fruit. Biochemical and transcriptomic analyses were carried out in fruits of IL12-4-SL in comparison with the cultivated line M82 at different stages of ripening. AsA content was studied in relation with pectin methylesterase (PME) activity and the degree of pectin methylesterification (DME). Our results indicated that the increase of AsA content in IL12-4-SL fruits was related with pectin de-methylesterification/degradation. Specific PME, polygalacturonase (PG) and UDP-D-glucuronic-acid-4-epimerase (UGlcAE) isoforms were proposed as components of the D-galacturonate pathway leading to AsA biosynthesis. The relationship between AsA content and PME activity was also exploited in PMEI tobacco plants expressing a specific PME inhibitor (PMEI). Here we report that tobacco PMEI plants, altered in PME activity and degree of pectin methylesterification, showed a reduction in low methylesterified pectic domains and exhibited a reduced AsA content. Overall, our results provide novel biochemical and genetic traits for increasing antioxidant content by marker-assisted selection in the Solanaceae family

Inhibition of inducible Nitric Oxide Synthase expression by an acetonic extract from Feijoa sellowiana Berg. fruits.

Feijoa sellowiana Berg. fruits and especially the acetonic extract have been shown to possess biological activities, although the responsible compounds have never been identified. The present study was designed to evaluate the anti-inflammatory activity of an acetonic extract from F. sellowiana Berg. fruits on the nitric oxide (NO) pathway, which plays an important role in inflammation. To this aim the J774 cell line, which expresses inducible nitric oxide synthase (iNOS) following stimulation with lipopolysaccharide (LPS), has been utilized, and the effects of this extract and its fractions on NO production, iNOS protein expression, and signal pathways involved in its regulation have been evaluated. This study demonstrates that at least some part of the anti-inflammatory activity of the acetonic extract is due to the suppression of NO production by flavone and stearic acid. The mechanism of this inhibition seems to be related to an action on the expression of the enzyme iNOS through the attenuation of nuclear factor κB (NF-κB) and/or mitogen-activated protein kinase (MAPK) activation

GC and GC-–MS Analysis of Volatile Compounds From Ballota nigra subsp. uncinata Collected in Aeolian Islands, Sicily (Southern Italy)

In the present study, the chemical composition of the essential oils from aerial parts of Ballota nigra subsp. uncinata (Beg.) Patzak collected in Sicily was evaluated by gas chromatography (GC) and GC-mass spectrometry. The main components of the oil were (E)-phytol (20.0%), alpha-pinene (9.0%), hexahydrofarnesyl acetone (5.7%), and alpha-selinene (5.1%). Cluster analysis of the essential oil compositions of all the taxa belonging to B. nigra s.l. group was performed

Analysis of essential oils from Scutellaria orientalis ssp. alpina and S. utriculata by GC and GC-MS.

The chemical composition of the essential oils obtained from aerial parts of Scutellaria orientalis L. ssp. alpina (Boiss.) O. Schwarz and S. utriculata Labill. growing wild in Lebanon, were analyzed by GC and GC-MS. In S. orientalis ssp. alpina, strongly characterized by sesquiterpenes (41.2%) and particularly sesquiterpene hydrocarbons (31.7%), hexahydrofarnesylacetone (11.7%) was recognized as the main constituent, together with hexadecanoic acid (7.6%), caryophyllene (7.4%), caryophyllene oxide (6.8%), 4-vinylguaiacol (5.4%) and germacrene D (5.4%). S. utriculata oil was instead constituted above all by monoterpenes (42.2%), particularly oxygen containing monoterpenes (39.9%), and in this oil the main compounds were linalool (20.1%), 4-vinyl guaiacol (15.5%), α-terpineol (8.9%), ( E)-nerolidol (8.9%) and geraniol (8.2%)

Cytotoxic properties of Marrubium globosum ssp. libanoticum and its bioactive components

Marrubium globosum Montbr. et Auch. ex Benth. ssp. libanoticum Boiss. (Lamiaceae) is a medicinal plant used in Lebanon for the treatment of inflammatory diseases, asthma, coughs and other pulmonary and urinary problems. The goal of our study was to assess the biological activity of M. globosum by testing different extracts of the aerial parts for their antiproliferative activity against human melanoma cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The chloroform fraction showed the greatest activity. The compounds isolated from the extracts were also tested: the mixture of (13 S)-9α,13α-epoxylabda-6β(19),16(15)-diol dilactone and (13 R)-9α,13α-epoxylabda-6β(19),16(15)-diol dilactone was the most active fraction, with an IC50 value of 29.2 ± 0.06 μg/mL

A Rapid Procedure for the Simultaneous Determination of Eugenol, Linalool and Fatty Acid Composition in Basil Leaves

Eugenol and linalool are often the most abundant volatile compounds found in basil (Ocimum basilicum L., Lamiaceae) leaves, and they are interesting for the aroma they provide and for their numerous beneficial bioactivities. Their determination is thus needed for several purposes. In the present study, to avoid the previous isolation of essential oil, the direct solvent extraction is proposed coupled with a transmethylation to convert acyl lipids into fatty acids methyl esters (FAMEs), thus assessing the possible simultaneous analysis of eugenol and linalool with FAMEs by gas chromatography coupled to flame ionization detector (GC-FID). The method has been validated and applied to ten basil leaves samples in which eugenol and linalool were found in mean concentrations of 2.80 +/- 0.15 and 1.01 +/- 0.04 g kg(-1) (dry weight), respectively. FAMEs composition was dominated by linolenic acid (52.1-56.1%) followed by palmitic acid (19.3-22.4%) and linoleic acid (9.6-11.3%). The ratio of n6-polyunsaturated fatty acids (PUFAs)/n3-PUFAs was in the range of 0.17-0.20 in the investigated samples. The proposed method exploits a rapid procedure requiring 40 min, making use of a small amount of solvent and allowing the simultaneous determination of molecules contributing to assess the quality of this worldwide appreciated herb

Chemical Composition of the Essential Oil from Aerial Parts of Stachys palustris L. (Lamiaceae) Growing Wild in Southern Italy

The paper reports the composition of the essential oil from aerial parts of Stachys palustris L. (Lamiaceae) from Southern Italy. The essential oil was extracted by hydrodistillation from selected plants and its chemical composition was determined by the GC-MS system on two fused- silica capillary columns of different polarity. The mass fraction of oil was 0.21 % on a dry weight basis. Altogether, 92 compounds were identified accounting for 93.6 % of the total oil, which was characterized mainly by carbonylic compounds (25.4 %), fatty acids and their esters (24.2 %), along with sesquiterpenoidic compounds (16.0 %) and phenols (11.2 %). The major components of the sample were caryophyllene oxide (7.8 %), hexahydrofarnesyl acetone (7.4 %), hexadecanoic acid (6.8 %), (Z,Z,Z)-9,12,15-octadecatrienoic acid (6.7 %), (Z)-phytol (6.4 %), thymol (5.8 %), p-methoxyacetophenone (5.1 %), 4-vinylguiacole (3. %), tetradecanoic acid (3.8 %), (E)-caryophyllene (3.6 %), b-ionone (3.3 %) and b-damascenone (3.0 %)

Anticancer activities of anthocyanin extract from genotyped Solanum tuberosum L. "Vitelotte"

n/

Controlled synthesis of the DSF cell–cell signal is required for biofilm formation and virulence in Xanthomonas campestris

Virulence of the black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is regulated by cell–cell signalling involving the diffusible signal factor DSF. Synthesis and perception of DSF require products of genes within the rpf cluster (for regulation of pathogenicity factors). RpfF directs DSF synthesis whereas RpfC and RpfG are involved in DSF perception. Here we have examined the role of the rpf/DSF system in biofilm formation in minimal medium using confocal laser-scanning microscopy of GFP-labelled bacteria. Wild-type Xcc formed microcolonies that developed into a structured biofilm. In contrast, an rpfF mutant (DSF-minus) and an rpfC mutant (DSF overproducer) formed only unstructured arrangements of bacteria. A gumB mutant, defective in xanthan biosynthesis, was also unable to develop the typical wild-type biofilm. Mixed cultures of gumB and rpfF mutants formed a typical biofilm in vitro. In contrast, in mixed cultures the rpfC mutant prevented the formation of the structured biofilm by the wild-type and did not restore wild-type biofilm phenotypes to gumB or rpfF mutants. These effects on structured biofilm formation were correlated with growth and disease development by Xcc strains in Nicotiana benthamiana leaves. These findings suggest that DSF signalling is finely balanced during both biofilm formation and virulence

Salicylic acid and melatonin alleviate the effects of heat stress on essential oil composition and antioxidant enzyme activity in Mentha × piperita and Mentha arvensis L

The aim of this study was to evaluate changes in the chemical profile of essential oils and antioxidant enzymes activity (catalase CAT, superoxide dismutase SOD, Glutathione S-transferases GST, and Peroxidase POX) in Mentha × piperita L. (Mitcham variety) and Mentha arvensis L. (var. piperascens), in response to heat stress. In addition, we used salicylic acid (SA) and melatonin (M), two brassinosteroids that play an important role in regulating physiological processes, to assess their potential to mitigate heat stress. In both species, the heat stress caused a variation in the composition of the essential oils and in the antioxidant enzymatic activity. Furthermore both Salicylic acid (SA) and melatonin (M) alleviated the effect of heat stress