Contribution to the characterisation of honey-based Sardinian product abbamele: Volatile aroma composition, honey marker compounds and antioxidant activity

Chemical Characterisation, Antidiabetic, Antibacterial, and In Silico Studies for Different Extracts of Haloxylon stocksii (Boiss.) Benth: A Promising Halophyte

The objective of the study is to evaluate the chemical characterisation, and biological and in silico potential of Haloxylon stocksii (Boiss.) Benth, an important halophyte commonly used in traditional medicine. The research focuses on the roots and aerial parts of the plant and extracts them using two solvents: methanol and dichloromethane. Chemical characterisation of the extracts was carried out using total phenolic contents quantification, GC-MS analysis, and LC-MS screening. The results exhibited that the aerial parts of the plant have significantly higher total phenolic content than the roots. The GC-MS and LC-MS analysis of the plant extracts revealed the identification of 18 bioactive compounds in each. The biological evaluation was performed using antioxidant, antibacterial, and in vitro antidiabetic assays. The results exhibited that the aerial parts of the plant have higher antioxidant and in vitro antidiabetic activity than the roots. Additionally, the aerial parts of the plant were most effective against Gram-positive bacteria. Molecular docking was done to evaluate the binding affinity (BA) of the bioactive compounds characterised by GC-MS with diabetic enzymes used in the in vitro assay. The results showed that the BA of γ-sitosterol was better than that of acarbose, which is used as a standard in the in vitro assay. Overall, this study suggests that the extract from aerial parts of H. stocksii using methanol as a solvent have better potential as a new medicinal plant and can provide a new aspect to develop more potent medications. The research findings contribute to the scientific data of the medicinal properties of Haloxylon stocksii and provide a basis for further evaluation of its potential as a natural remedy.

Evolution of Physicochemical Parameters during the Thermal-Based Production of Água-mel, a Traditional Portuguese Honey-Related Food Product

The purpose of this work was to investigate the physicochemical changes occurring during the thermal-based production of água-mel, a traditional Portuguese honey-related food product. The refractive index, color parameters (hue angle, H°; chroma, C*), and the content of total reducing sugars, glucose, fructose, total brown pigments, and 5-hydroxymethylfurfural were monitored along the entire production process, and their evolution was kinetically modelled. Thermal processing caused a gradual decrease in sugars, which was accompanied by the formation of brown pigments and 5-hydroxymethylfurfural, increased concentration of soluble solids as evaluated through refractive index measurements, as well as the appearance of darker colors. In particular, a zero-order kinetic model could explain the changes in H° and reducing sugars, while the evolution of refractive index, brown pigments, 5-hydroxymethylfurfural, C*, fructose, and glucose were best fitted using a first-order kinetics model.

Biotoxicological Analyses of Trimeroside from Baccharis trimera Using a Battery of In Vitro Test Systems

The use in folk medicine of Baccharis trimera and recent studies on DNA damage by oxidative stress mechanisms have motivated this study. We investigated the biotoxicological effects of trimeroside from this plant. Aqueous extract from aerial parts of B. trimera was fractioned by flash chromatography for further isolation by thin-layer chromatography. The novel nor-monoterpene glycoside, trimeroside, and three flavonoids, cirsimaritin, luteolin and quercetin, were isolated. The genotoxic and mutagenic potential of trimeroside was determined by Salmonella/microsome (TA98 and TA100), comet assay, and cytokinesis-block micronucleus cytome assay (CBMN-cyt) in HepG2 cells. We also screened trimeroside into different human tumoral cell lines by sulforhodamine B (SRB) assay. Mutagenicity was detected in TA100 strain with metabolic activation. Genotoxic effects were not observed in HepG2 by comet assay. However, a decrease in the nuclear index division in the 2.0 mg·mL⁻¹ concentration and an increase of nucleoplasmic bridges in the 1.5 mg·mL⁻¹ concentration were detected by CBMN-cyt assay indicating cytotoxic and mutagenic effects. In SRB assay, trimeroside showed weak antiproliferative activity against the cell lines.

Optimization of the Extraction of the Volatile Fraction from Honey Samples by SPME-GC-MS, Experimental Design, and Multivariate Target Functions

Head space (HS) solid phase microextraction (SPME) followed by gas chromatography with mass spectrometry detection (GC-MS) is the most widespread technique to study the volatile profile of honey samples. In this paper, the experimental SPME conditions were optimized by a multivariate strategy. Both sensitivity and repeatability were optimized by experimental design techniques considering three factors: extraction temperature (from 50°C to 70°C), time of exposition of the fiber (from 20 min to 60 min), and amount of salt added (from 0 to 27.50%). Each experiment was evaluated by Principal Component Analysis (PCA) that allows to take into consideration all the analytes at the same time, preserving the information about their different characteristics. Optimal extraction conditions were identified independently for signal intensity (extraction temperature: 70°C; extraction time: 60 min; salt percentage: 27.50% w/w) and repeatability (extraction temperature: 50°C; extraction time: 60 min; salt percentage: 27.50% w/w) and a final global compromise (extraction temperature: 70°C; extraction time: 60 min; salt percentage: 27.50% w/w) was also reached. Considerations about the choice of the best internal standards were also drawn. The whole optimized procedure was than applied to the analysis of a multiflower honey sample and more than 100 compounds were identified.

Volatiles, color characteristics and other physico-chemical parameters of commercial Moroccan honeys

Seven commercial Moroccan honeys were considered for chemical characterisation. Volatile fraction, total polyphenols content, antioxidant and antiradical activities were evaluated by employing different analytical methodologies. Several physical parameters such as refractive index, pH, water content, solids content and colour were measured. Volatile fraction revealed an abundant presence of cis- and trans-linalool oxide in the seven studied samples. The presence of high levels of compounds related to the Maillard reaction, like furfural and hydroxymethylfurfural, could be the result of thermal treatments used to liquefy commercial honeys or of long storage times. The CIE L*a*b*C*(ab)h°(ab) chromatic coordinates confirmed the advanced stage of the Maillard reaction, showing L* values lower than the common values found for honey of similar typologies.

Physicochemical Parameters and Bioactive Compounds of Strawberry Tree (Arbutus unedoL.) Honey

Botanical origin, physicochemical properties (ash, colour, diastase activity, electrical conductivity (EC), hydroxymethylfurfural (HMF), moisture, optical rotation (OP), pH, reducing sugars, total acidity, total soluble solids, and water activity), bioactive compounds (BC), and antioxidant activity obtained from strawberry tree honey from South Portugal were investigated. Results showed that the pollen analysis and physicochemical parameters were found within to meet international honey specifications. Significant differences (P<0.05) in results of ash content, EC, HMF, OP and colour when were compared with analogous famous Italian honey (Sardinia island). For BC, total phenolic and total flavonoid content were 94.47 mg gallic acid/100 g and 5.33 mg quercetin/100 g, respectively. Concerning Portuguese honey, it was also found that radical scavenging activity (DPPH assay) was 43.46% and antioxidant activity was 18.85 mg ascorbic acid equivalent/100 g and 9.92 mg quercetin equivalent/100 g. These results confirmed that Portuguese strawberry tree honey has the highest antioxidant activity, when compared with other kinds of honey. This complete report demonstrates advantages and can help to promote consumption and shown their benefical properties (e.g., antioxidant); which will may increase the commercial value.

Comparative analysis of Tunisian wild Crataegus azarolus (yellow azarole) and Crataegus monogyna (red azarole) leaf, fruit, and traditionally derived syrup: phenolic profiles and antioxidant and antimicrobial activities of the aqueous-acetone extracts

Quantitative and qualitative analyses of the yellow and red azarole phenolic extracts prepared from leaf, fruit peel/pulp, and syrup were comparatively investigated. The yellow azarole was found significantly richer in polyphenols than the red-fruit species. Hyperoside was the main phenolic in both yellow and red azarole leaves and only in yellow fruits, whereas procyanidin B2 was the major compound in red fruits. Yellow azarole leaf and fruit peel extracts exhibited the strongest antioxidant activities using DPPH (≈168 and 79 μmol TEAC/g fw, respectively) and FRAP (≈378 and 161 μmol Fe(2+)/g fw, respectively) assays. The highest antibacterial activities were recorded for the yellow azarole leaf and fruit peel extracts, especially against Staphylococcus aureus and Streptococcus faecalis . The low phenolic content of the syrups contrasted with their significant antioxidant and antimicrobial potentials, which were correlated to their hydroxymethylfurfural (HMF) (furan derivative amounts) content.

Analysis of the flavonoid component of bioactive New Zealand mānuka (Leptospermum scoparium) honey and the isolation, characterisation and synthesis of an unusual pyrrole

The flavonoid components of New Zealand mānuka (Leptospermum scoparium) honey have been quantified in a series of 31 honeys of varying non-peroxide antibacterial activity to clarify discrepancies between previous studies reported in the literature. Total flavonoid content was 1.16 mg/100 g honey. The principal flavonoids present were pinobanksin, pinocembrin, luteolin and chrysin and together these represented 61% of the total flavonoid content. 1, 2-formyl-5-(2-methoxyphenyl)-pyrrole, which was weakly correlated with the non-peroxide antibacterial activity, was isolated from the flavonoid fraction and separately synthesised. 1 did not display inhibitory activity against Staphylococcus aureus in vitro and thus the origin of the correlation, which is still unknown, is not a direct contribution.