Current Bioactive Compounds - Volume 8, Issue 3, 2012

Guaiacol and 4-methylguaiacol are routinely used as markers to determine extent of smoke impact on winegrapes and wines. However, smoke contains a complex group of compounds that may contribute to smoke taint in winegrapes and wine. In this study, a gas chromatography-mass spectrometry (GC-MS) based analytical method was developed and validated for the profiling of various smoke taint compounds in wines made from smoke affected fruit. A total of 22 analytes were separated and identified in the GC-MS chromatogram, all of which were selected to evaluate the samples and precision of the method. The GC-MS method showed good repeatability/reproducibility with intra- and inter-day relative standard deviation (RSD) of ±14%. The method was used to demonstrate that the smoked grapes and resultant wines, compared to unsmoked wines, contained significantly enhanced levels of guaiacol and 4-methylguaiacol along with other lignin derived phenols such as cresols and syringol. In smoke affected grapes and young wines, volatile phenols exist as glyco-conjugates (potential taint), which hydrolyse slowly leading to unacceptable levels of taint accumulation in wine during storage. The GC-MS method reported here, in conjunction with the optimised acid hydrolysis of phenol glycoconjugates, was successfully used to determine potential levels of smoke taint compounds in wines. Thus, the method can be used for screening smoke exposed grapes for potential taint levels prior to wine making. The results presented here highlight the need to include an array of smoke derived phenols to develop a complete picture of smoke taint and associated aroma in affected grapes and wines.

Grape tannin content and composition studies have been limited to a few varieties. To determine whether grape tannin composition was generic or variety specific, we examined skin tannins in 36 cultivars. Tannins were analyzed by phloroglucinolysis and gel permeation chromatography (GPC). Concentration ranged from 1.3 (Malbec) to 15.6 mg/g fresh weight of skin (Red Emperor). Catechin terminal subunits ranged from 45.6% (Lagrein) to 78.5% (Black Rose), epicatechin from 19.0% (Black Rose) to 49.7% (Lagrein) and epicatechin-gallate from 1.0% (Muscat Hamburg) to 8.4% (Barbera). Epigallocatechin was not observed as a terminal subunit. Catechin extension subunits ranged from 1.4% (Pinot Gris) to 6.2% (Beauty Seedless), epicatechin from 36.3% (Cienna) to 69.1% (Cardinal), epicatechin-gallate from 2.3% (Pinot Gris) to 11.5% (Beauty Seedless) and epigallocatechin from 22.6% (Cardinal) to 53.7% (Cienna). Average polymer length by phloroglucinolysis ranged from 6.6 (Malbec) to 46.1 subunits (Lagrein). In the GPC fraction containing the largest polymers, lengths ranged from 38.1 (Barbera) to 112.4 subunits (Flame Seedless). Polymer lengths were in many cases greater than previous reports. While there was inter-specific variation in tannin content and composition, terminal units were generally catechin or epicatechin and extension subunits epicatechin or epigallocatechin. A weak relationship was observed between total tannin and average polymer length (R2=0.46). Tannin content and polymer length was often higher in table grapes than winegrapes. Understanding tannin diversity between grape varieties underpins planting, harvesting and blending decisions to produce wines that meet consumer expectations.

Agave has been used as a raw material for food and folklore medicinal purposes. Traditional processing involves the use of agave as a source of carbohydrate-rich syrups for direct use or as substrate to yield hydrolyzed fermented products and spirits. Agave plants can accumulate significant amounts of inulin, important molecule with prebiotic activity. The agave plant has been used to feed ruminants in arid areas where drought episodes are prevalent. This plant is an important source of saponins, considered as antinutritional factors but also as anticancer, antifungal, and antiinflammatory agents. Considering the low hydrosolubility of saponins, these compounds are not being recovered from the plant and alternative processes need to be devised. Agave also contains polyphenols with activities such as: anticancer, antioxidant, antidiabetic, anti-inflammatory, antiparasitical, antimicrobial, prebiotics and coadjuvant in mineral absorption. The full phytochemical characterization of the sap, leaves and byproducts generated from the traditional food uses is needed to validate the beneficial effects of agave consumption and its potential use as a source of functional ingredients.

Olive biophenols affect the organoleptic and nutraceutical properties of fruits; therefore, it is an emerging research field. In addition, a plethora of health-promoting properties have been attributed to the phenolic content of olive fruits. The main biophenols can be divided into different sub-groups such as phenolic acids and alcohols, flavonoids, lignans and secoiridoids. The latter sub-group of biophenols is typical in olive fruits, since oleuropein and the products of its biotransformation characterize olive fruit. An array of genetic, agronomic and technological factors that affect the rate of synthesis and biotransformation of secoiridoids in olive fruits is discussed. Furthermore, the relationship between antioxidant activity and structures of olive biophenols is explored.

Flavonoids are a broad class of polyphenolic secondary metabolites widely dispersed throughout the plant kingdom and found in substantial levels in commonly consumed fruits, vegetables and beverages. These compounds have aroused considerable interest because of their potential beneficial biochemical and antioxidant effects on human health. The structures of flavonoids are characterized by a fifteen-carbon backbone consisting of two aromatic and one oxygenated rings. Flavonoids could be divided into various types of monomeric aglycones, bi-, tri-, and oligo-flavonoids including proanthocyanidins. Owing to the importance of flavonoids, isolation and structural elucidation of natural flavonoids play an important role in many areas of science. This is generally performed by a combination of chromatographic and spectroscopic methods, including ultraviolet, nuclear magnetic resonance and mass spectrometry. Among all these techniques, mass spectrometry remains an important tool for the identification and structural determination of flavonoids. Its advantages are high sensitivity and possibilities of hyphenation with liquid chromatographic methods for the analysis of mixtures of compounds. Different desorption ionization methods allow the analysis of underivatized glycosides. Advances in mass spectrometry methodology have been shown to be extremely valuable for flavonoid analysis especially the use of mild ionization techniques, which have improved the possibility of recording molecular ions and suppressed the detection limits by several orders of magnitude. Detailed structural information can be obtained by resorting to cone voltage fragmentation and use of various types of mass analyzers. In this chapter, examples of the usefulness of mass spectroscopy techniques to the structural characterization of various flavonoids will be presented. In particular analysis of flavonoid aglycones and mono and di-O-glycosides, oligomeric and polymeric procyanidins using electropsray (ESI), matrix-assisted laser desorption ionization (MALDI), and tandem (MS/MS) mass spectrometry will be also presented.

The discovery of Helicobacter pylori (H. pylori), the curved or spiral shaped bacteria, as the main etiologic organism of chronic gastritis, peptic ulcer disease, and gastric cancer was one the most significant discoveries in gastroenterology of the twentieth century. Helicobacter infections promote infiltration of the gastric mucosa by neutrophils, macrophages, and T and B lymphocytes, and leaves the host prone to complications resulting from chronic inflammation. If left untreated, persistent gastrointestinal infections and chronic gastritis may evolve into more severe diseases, such as peptic ulcer or atrophic gastritis. In addition, infection with H. pylori increases the risk of developing gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. Helicobacter pylori infections are of great concern worldwide due to increasing antimicrobial resistance and high re-infection rates. In the 1990's scientific evaluation of natural products and ethnomedicines for the treatment of H. pylori infections began in earnest, and many natural products have been investigated over the past 20 years with promising in vitro results. This review highlights these achievements and the classes of naturally occurring compounds with activity against H. pylori. It also points out the critical need of new treatments for H. pylori infections due to increasing global resistance.

Annona species have been used as a natural remedy for a variety of illnesses with antiparasitic, antispasmodic, antidiarrheal, antiulcer, sedative, analgesic, hypotensive, and vermifugal effects. These properties are due to the presence of a number of bioactive compounds on the leaves, fruit, seeds, and stem. The aim of this review is to show the main species of Annona, their medicinal properties and the chemical constituents that may be related to these effects. In the leaves it is possible to find acetogenins, annopentocins A, B, and C, cis- and trans-annomuricin-D-ones, goniothalamicin, arianacin, and javoricin, related to anticancer properties. Quercetin-3-O-glucoside, also found in the leaves mediates antidiabetic and antioxidative effects. In the fruit are found annonaine, nornuciferine and asimilobine, associated to antidepressive effects. In the seeds are found muricatetrocin A and muricatetrocin B, longifolicin, corossolin, corossolone, uvarigrandin A, bullatacin, squamotatin. These acetogenins are associated with anticancer effects. Cyclosquamosin B, quercetin, and cyclosquamosin from the seeds have respectively vasorelaxant, antithyroidal and, antiinflammatory activity. In the stem parts there are several components as N-trans-feruloyltyramine, N-p-coumaroyltyramine, and N-trans-caffeoyltyramine, lignans, syringaresinol, syringaldehyde, beta-sitosterol and beta-sitosterol-beta-D-glucoside which exhibit antiplatelet aggregation activity. Copaene, patchoulane, 1H-cycloprop (e) azulene and kaur-16-en-19-oic acid found in the barks exhibit significant central as well as peripheral analgesic and antiinflammatory activities. The properties of the biological compounds in Annona species support information that may provide validation for its medicinal uses, but further studies should be performed to establish ideal and safe doses of consumption to ensure the effectiveness of the benefits.

Bioactivity of the cytoskeleton proteins such as actin, myosin and titin that have been extracted from the rabbit muscle was analyzed on plant misrospores as unicellular biosensors. The fibrillar forms of the proteins stimulated the germination of vegetative microspores from horsetail Equisetum arvense and generative (pollen) microspores from knight’s star Hippeastrum hybridum. In special experiments the proteins tested were able to reverse the blockade of ion channels by drugs d-tubocurarine and α-bungarotoxin, acting on cholinoreceptors, or verapamil, regulating Ca2+-channels.

The antifeedant activities of camptothecin 1 and its semisynthetic derivatives 2-12 were evaluated against an economically important pest, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Simple chemical conversions were carried out on the natural camptothecin obtained from a Chinese medicinal plant Camptotheca acuminate. These conversions focused on different functional modified sites in the camptothecin skeleton considered to be important for the biological activity. Among all the tested compounds, compounds 4, 5, 7 and 8 displayed more promising antifeedant activity than camptothecin 1. Especially compound 7 was found to exhibit exceptionally potent antifeedant activity with AFC50 values of 92.03μg/mL, compared to 1 and toosendanin, a commercial insecticide derived from Melia azedarach (IC50 528.40μg/mL and 91.68μg/mL, respectively). The different antifeedant activity range of compounds 1-12 indicated that variation of chemical structures in the camptothecin skeleton markedly affected the activity profiles of this compound class, and some preliminary SAR information has been observed from it.