Analytical approaches to the determination of simple biophenols in forest trees such as Acer(maple), Betula(birch), Coniferus, Eucalyptus, Juniperus(cedar), Picea(spruce) and Quercus(oak)

Phototransformation of Lignin-related Compounds in Chromophoric Dissolved Organic Matter Solutions

Lignin is a major terrestrial source of chromophoric dissolved organic matter (CDOM), and studying the phototransformation of lignin monomers and their related compounds can enhance our understanding of CDOM intramolecular interactions. Coniferyl aldehyde (Coni) and sinapaldehyde (Sina) form ground-state complexes with CDOM, with equilibrium constants of 7,800 (± 1,800) and 20,000 (± 2,000) M-1, respectively. In comparison, vanillin (Van) exhibits minimal affinity for CDOM complexation. The bimolecular reaction rate constants between singlet oxygen (1O2) and these phenolic carbonyl compounds ranged from 0.46 (± 0.02) to 1.8 (± 0.1) × 107 M-1s-1, which is approximately one order of magnitude lower than their reaction rate constants (0.51 (± 0.02)-1.25 (± 0.02) × 108 M-1s-1) with the triplet excited state of CDOM (3CDOM*). In acidic CDOM solutions (pH 5.0), 1O2, H2O2, and organic peroxyl radicals had negligible impact on the transformation. Comparing the initial transformation rate in the presence and in the absence of NaN3 or furfuryl alcohol led to an overestimation of the contribution of 1O2 to the transformation of Van, Coni, or Sina. 3CDOM* scavengers could not fully inhibit the transformation of Coni or Sina. The remaining transformation is considered to arise from either the unquenched intra-CDOM phase 3CDOM* or a fraction of Coni⊂CDOM or Sina⊂CDOM complex, which underwent intramolecular photoinduced chemical reactions.

A new method for simultaneous determination of 14 phenolic acids in agricultural soils by multiwavelength HPLC-PDA analysis

There are phenolic acids with allelopathy in the rhizosphere soil of plants. At present, the identification and quantification of phenolic acids in different matrix mixtures is usually analysed by high performance liquid chromatography, but the detection of phenolic acids in soil has rarely been studied. As well as, previous studies have evaluated a limited number of target compounds. In this work, we proposed and verified a method for quantitative determination of 14 phenolic acids, including gallic acid, vanillic acid, p-hydroxybenzoic acid, protocatechuic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, chlorogenic acid, benzoic acid, salicylic acid, 2-methoxycinnamic acid, 3-methoxycinnamic acid, and cinnamic acid, which are widely present in rhizosphere soil of plants and have allelopathy. This method used multiwavelength HPLC-PDA analysis for simultaneous determination of these compounds. The detection wavelengths selected 254 nm, 280 nm, 300 nm, and 320 nm. Chromatographic separation of all compounds was achieved using a column of Shim-pack VP-ODS (250 mm × 4.6 mm, 5 μm), kept at 30 °C. Mobile phase A was acetonitrile, B was a 0.5% acetic acid aqueous solution, and the flow rate was 1.0 mL min⁻¹. Under the condition of gradient elution, the mobile phase A was acetonitrile, B was a 0.5% acetic acid aqueous solution, and the flow rate was kept constant at 1.0 mL min⁻¹. The 14 target phenolic acids were completely separated within 45 min. All the calibration curves showed good linearity, and the correlation coefficient was 0.9994–0.9999. With the detection limit varying from 0.003 mg L⁻¹ to 0.239 mg L⁻¹. The recovery rates and the RSD of 14 phenolic acids were 80.54∼107.0% and 1.43–4.35%, respectively. This method has the characteristics of high sensitivity, high accuracy, and high recovery rate. This method is a novel technical means for the simultaneous analysis of compound phenolic acids in soil.

A method for multiple phenolic acids in soil based on HPLC-PDA multi-wavelength analysis was established. The method is high sensitivity, high accuracy and stable sample, and can be used for quantitative analysis of phenolic acids in soil.

Optimization of the process of aromatic and medicinal plant maceration in grape marc distillates to obtain herbal liqueurs and spirits

BACKGROUND

Herbal liqueurs are alcoholic beverages produced by the maceration or distillation of aromatic and medicinal plants in alcohol, and are also highly valued for their medicinal properties. The process conditions, as well as the number and quantity of the plants employed, will have a great influence on the quality of the liqueur obtained. The aim of this research was to optimize these important variables.

RESULTS

A Box-Benhken experimental design was used to evaluate the independent variables: alcohol content, amount of plant and time during the experimental maceration of plants in grape marc distillate. Four plants were assessed, with the main compound of each plant representing the dependent variable evaluated with respect to following the evolution of the maceration process. Bisabolol oxide A in Matricaria recutita L., linalool in Coriander sativum L. and eucalyptol in Eucalyptus globulus Labill. were quantified using a gas chromatography-flame ionization detector. Glycyrrhizic acid in Glycyrrhiza glabra L was determined using a high-performance liquid chromatography-diode array detector. Other dependent variables were also evaluated: total phenolic content, color parameters and consumer preference (i.e. appearance).

CONCLUSION

The experimental designs allowed the selection of the optimal maceration conditions for each parameter, including the preference score of consumers: 70% (v/v) of ethanol, 40 g L^-1 plant concentration and a maceration process of 3 weeks. © 2016 Society of Chemical Industry.

Exploration of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays

AIM

To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.

METHODS

The leaf extracts of the three different Eucalyptus species [E. globulus (EG), E. citriodora (EC), E. camaldulensis (ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors (NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.

RESULTS

Major bioactive compounds like polyphenols (341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids (4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation (R(2) = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.

CONCLUSION

These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.

Exploration of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays

AIM

To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.

METHODS

The leaf extracts of the three different Eucalyptus species [E. globulus (EG), E. citriodora (EC), E. camaldulensis (ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors (NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.

RESULTS

Major bioactive compounds like polyphenols (341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids (4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation (R(2) = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.

CONCLUSION

These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.

Chemo-profiling of eucalyptus and study of its hypoglycemic potential

Constant escalations in the number of diabetics world-wide and the failure of conventional therapy to restore normoglycemia without adverse effects, in spite of tremendous strides in modern medicine, calls for naturopathy and alternative medicine. Because diabetes is multi-factorial and has secondary complications, prevention of hyperglycemia is the central dogma for its management. To date, no oral hypoglycemic exists which can achieve tight glycemic control without side effects. Dietary adjuncts, lifestyle interventions and a resurgence of interest in phyto-therapy have consequently gained ground. Natural hypoglycemics have attracted attention due to ease of incorporation in everyday diet, affordability, less adverse effects, and long term safety. Ethno botanical literature reports more than 800 anti-diabetic plants species. Eucalyptus is well represented in the Aboriginal Pharmacopoeias for its various pharmacological activities. Its hot aqueous decoction has been used as a hypoglycemic in various regions of world. This editorial attempts to summarize the data on the hypoglycemic potential of the different eucalyptus species, highlight the value of its natural biomolecules for the prophylaxis and treatment of type 2 diabetes, describe their mechanistic actions, shed light on the posology and safety aspects of eucalyptus and assess its applicability as a reinforcement to currently used therapy.

Phenols in leaves and bark of Fagus sylvatica as determinants of insect occurrences

Beech forests play an important role in temperate and north Mediterranean ecosystems in Greece since they occupy infertile montane soils. In the last glacial maximum, Fagus sylvatica (beech) was confined to Southern Europe where it was dominant and in the last thousand years has expanded its range to dominate central Europe. We sampled four different beech forest types. We found 298 insect species associated with beech trees and dead beech wood. While F. sylvatica and Quercus (oak) are confamilial, there are great differences in richness of the associated entomofauna. Insect species that inhabit beech forests are less than one fifth of those species living in oak dominated forests despite the fact that beech is the most abundant central and north European tree. There is a distinct paucity of monophagous species on beech trees and most insect species are shared between co-occurring deciduous tree species and beech. This lack of species is attributed to the vegetation history and secondary plant chemistry. Bark and leaf biophenols from beech indicate that differences in plant secondary metabolites may be responsible for the differences in the richness of entomofauna in communities dominated by beech and other deciduous trees.

Flavonol quantification and stability of phenolics in fermented extracts from fresh Betula pendula leaves

An HPLC method, which allows reliable quantitation of flavonols and other phenolics in birch leaf extracts, was developed and validated. The method was applied to study the bioconversion of flavonols in fermented aqueous extracts. Almost 100% of the flavonols were converted during the 12 months observation period. The generated phenolics as well as consecutive conversion products were identified by HPLC-DAD, LC-MS and GC-MS techniques.

Utilizing of Square Wave Voltammetry to Detect Flavonoids in the Presence of Human Urine

About biological affecting of flavonoids on animal organisms is known less, thus we selected flavonoids, flavanones and flavones, and their glycosides, which were examined as potential inducers of cytochrome(s) P450 when administrated by gavages into experimental male rats. The study was focused on induction of CYP1A1, the major cytochrome P450 involved in carcinogen activation. The data obtained demonstrate the necessity of taking into account not only ability of flavonoids to bind to Ah receptor (induction factor) but also to concentrate on their distribution and metabolism (including colon microflora) in the body. After that we examined certain flavonoids as potential inducers of cytochrome P450, we wanted to suggest and optimize suitable electrochemical technique for determination of selected flavonoids (quercetin, quercitrin, rutin, chrysin and diosmin) in body liquids. For these purposes, we selected square wave voltannetry using carbon paste electrode. Primarily we aimed on investigation of their basic electrochemical behaviour. After that we have optimized frequency, step potential and supporting electrolyte. Based on the results obtained, we selected the most suitable conditions for determination of the flavonoids as follows: frequency 180 Hz, step potential 1.95 mV/s and phosphate buffer of pH 7 as supporting electrolyte. Detection limits (3 S/N) of the flavonoids were from units to tens of nM except diosmin, where the limit were higher than μM. In addition, we attempted to suggest a sensor for analysis of flavonoids in urine. It clearly follows from the results obtained that flavonoids can be analysed in the presence of animal urine, because urine did not influence much the signals of flavonoids (recoveries of the signals were about 90 %).