Antioxidant Activity and Phenolic Compound Identification and Quantification in Western Australian Honeys

UPLC-Q-TOF-MS/MS identification, antioxidant, and alpha-glucosidase inhibition activities of three forms of phenolic compounds from Yemeni jujube fruit: In vitro and in silico investigations

Jujube fruits have rich medicinal value due to their biological properties which are affected mainly by geographical locations. This study investigates the antioxidant properties of free fraction (FF), esterified fraction (EF), bound fraction (BF), and other metabolites prepared from dried Yemeni jujube fruit and compare to those previously reported in the literature. Results from UPLC-Q-TOF-MS/MS analysis showed that this fruit consists of a total of 33, 26, and 27 free, esterified, and bound compounds identified, respectively. In terms of ABTS, DPPH, FRAP, and H2O2 assays, the BF exhibited values 1.2, 1.3,1.3, and 1.4 times higher than those of the FF, and similarly, 1.8, 1.9,2.0, and 2.5 times higher than the EF. A similar trend was observed in the inhibition of α-glucosidase (α-Glu), where the BF was 1.6, and 2.4 times more effective compared to the FF and EF, respectively. In silico analysis showed that flavonoids, the key active compounds, had substantial α-glucosidase binding capacity. In the meat model, all fractions inhibited protein and lipid oxidation during storage, and the BF exhibited the highest antioxidant capacity. This study provides the first investigation of the structure of active compounds and their biological properties in Yemeni jujube fruit. Yemeni fruits can be utilized as natural antioxidants, and nutraceuticals in food preservation, and medicine respectively.

Chemical Profiles and Biological Effects of Polyphenols in Eucalyptus Genus: A Comprehensive Review on Their Applications in Human Health and the Food Industry

The genus Eucalyptus is an important member of the family Myrtaceae. Eucalyptus plants contain unique and diverse phytochemicals, contributing to their remarkable ecological and economic values. Although the chemical components of several Eucalyptus food products (e.g., essential oil, honey, and wax) have been studied, research efforts are directed to other less characterized Eucalyptus phytochemicals, particularly polyphenols. Notably, some Eucalyptus polyphenols, such as formyl phloroglucinol meroterpenoids, have unique chemical structures with promising health-promoting effects. Thus, chemical characterization and biological evaluation of Eucalyptus polyphenols are critical to promoting their applications. Herein, this review provides a comprehensive summary of the phytochemical studies of Eucalyptus polyphenols and their biological activities, including antimicrobial, antiviral, anticancer, antioxidant, and anti-inflammatory effects. Eucalyptus polyphenols' structure-activity relationship is analyzed in the context of the development of their biological applications. In addition, the utilization of polyphenols from Eucalyptus plants in food preservation and production is summarized.

Antioxidant, anti-inflammatory, and anti-apoptotic activities of saffron and eryngium honey extracts

Saffron and Eryngium honeys are unique types of monofloral honeys collected from eastern and center of Iran. In present study, first, we investigated melissopalynological and physicochemical parameters in honey samples. Then we extracted the phenolic compounds and evaluated in vitro antioxidant by FRAP assay and anti-inflammatory activities by lipopolysaccharide induced RAW 264.7 macrophage cells. Phenolic extracts reduced nitric oxide and the secretion of the inflammatory cytokines IL-6 and TNFSF9 in the inflamed cells, and by reducing the NF-kB and increasing Nrf2 gene expression, showed an anti-inflammatory effect, but in general, Eryngium honey showed higher anti-inflammatory properties. Also, by studying the expression of Bcl-2, Bax and HO-1 genes, we showed that there is a relationship between inflammation and apoptosis in macrophage cells that the phenolic compounds showed their anti-apoptotic properties. Eryngium honey had a better performance in anti-apoptotic properties. Moreover, promising results indicate that Iranian honeys could be an important source of phenolic compounds presenting antioxidant and anti-inflammatory activity, which can have health-promoting properties if included in the diet and medicine.

Physicochemical Characteristics, Antioxidant Properties, and Identification of Bioactive Compounds in Australian Stingless Bee Honey Using High-Performance Thin-Layer Chromatography

This study investigates the physiochemical properties, chemical composition, and antioxidant activity of Australian stingless bee honey blends from two bee species, Tetragonula carbonaria and Tetragonula hockingsi, harvested in Burpengary East, Queensland at different times of the year. The moisture content of the honey samples ranged from 26.5% to 30.0%, total soluble solids from 70.0 to 73.5° Brix, and pH from 3.57 to 4.19. The main sugars identified were trehalulose (13.9 to 30.3 g/100 g), fructose (12.9 to 32.3 g/100 g), and glucose (4.80 to 23.7 g/100 g). The total phenolic content (TPC), measured using the Folin-Ciocalteu assay, ranged from 26.1 to 58.6 mg of gallic acid equivalents/100 g. The antioxidant activity was investigated with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, with values ranging from 1.39 to 6.08 mmol of Trolox equivalents/kg. Antioxidant constituents were determined using a High-Performance Thin-Layer Chromatography (HPTLC)-DPPH assay. The HPTLC-DPPH analysis revealed that honey samples collected in May 2022 contained the highest number of antioxidant compounds. Some constituents were identified using an HPTLC-derived database and also quantified utilising HPTLC analysis. Lumichrome was present in all honey samples, while luteolin and kaempferide were detected only in some. Kaempferol or isorhamnetin was also found to be present, although a definitive distinction between these two chemically closely related compounds could not be made by HPTLC analysis. The results showed that honey produced by Tetragonula hockingsi and Tetragonula carbonaria shares similar properties and composition when harvested at the same time, with only minor differences in moisture, fructose, and glucose content.

Phenolic Acid and Flavonoid Content Analysis with Antioxidant Activity Assessment in Chinese C. pi. Shen Honey

The nutritional value of honey is closely related to its components, which are highly influenced by the botanic origin. C. pi. Shen (Codonopsis pilosula (Franch.) var. modesta (Nannf.) L. T. Shen), a key plant in traditional Chinese medicine, mainly produced in Gansu Province of China, has attracted much attention for its medicinal value. However, there are few reports about C. pi. Shen honey. Therefore, this study aimed to evaluate the contents of phenolic profiles and antioxidant activities in C. pi. Shen honey by colorimetric, UPLC-MS/MS, Ferric ion Reducing Antioxidant Power (FRAP), 2,2-bisazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) (ABTS) free radical capacity, and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) scavenging ability methods. In comparison with four other high-yield unifloral honeys in China (Acacia honey, linden honey, rape honey, and jujube honey), C. pi. Shen honey demonstrated remarkable advantages. Specifically, the levels of total phenolic acids, total flavonoids, and phenolic components of C. pi. Shen honey were significantly pronounced, especially protocatechuic acid and kaempferol. Furthermore, the antioxidant activity of C. pi. Shen honey was also excellent, which was attributed to its phenolic compounds, underscoring its potential biological value. This study is anticipated to serve as a reference for the identification, nutritional assessment, and functional advancement of C. pi. Shen honey.

Correlation between Honey Parameters and Wound Healing Properties: The Case of Piedmont (Italy) Samples

INTRODUCTION

Honey possesses several positive properties, making it effective in wound healing mechanisms. However, very little information is available on the different honey types for wound healing activity.

METHOD

In the first "Academy of Sciences", a public engagement project with high school students, we assessed the properties of thirteen kinds of honey from the Piedmont area (Nord West Italy). In particular, we characterized the color intensity (by Pfund scale), total phenolic content (TPC), total flavonoid content (TFC), H2O2 production, and wound closure rate.

RESULTS

Then, we tried to verify the presence of a correlation between these parameters, finding a positive correlation between H2O2 and wound closure rate.

CONCLUSION

These data pave the way to characterize different types of Italian honey to completely understand its potential.

Plant-derived and dietary phenolic cinnamic acid derivatives: Anti-inflammatory properties

Cinnamic acids are aromatic acids primarily found in plants and plant-derived food. Phenolic cinnamic acids, with one or more hydroxyl groups in the aromatic ring, often contribute to the biological activities attributed to these compounds. The presence of hydroxyl groups and a carboxyl group makes cinnamic acids very hydrophilic, preventing them from crossing biological membranes and exerting their biological activities. To alleviate this condition, a panel of synthetic modifications have been made leading to a diverse set of phenolic cinnamic structures. In this review, an overview of the natural phenolic cinnamic acid derivatives and their plant sources (more than 200) is described. The synthetic approaches to obtain the referred derivatives (more than 200) namely esters and amides are reviewed. Further, their anti-inflammatory activity (more than 70 compounds) is scrutinized. Finally, future directions will be indicated to translate the research on phenolic cinnamic derivatives into potentially effective anti-inflammatory drugs.

Effects of Different Packaging Types and Storage Periods on Physicochemical and Antioxidant Properties of Honeys

Preserving the nutritional value of honey without compromising its properties until consumption is crucial. However, different types of honey may respond differently to packaging and storage conditions. This study aimed to assess the effects of different packaging materials (tin cans, light-colored glass jars, and dark-colored glass jars) and storage durations (initial, 6 months, and 12 months) on the physicochemical and antioxidant properties of pine, flower, and thyme honey. Nine samples were collected to conduct study on the three different types of honey. Honey samples were packaged in these materials and analyzed at the start, after 6 months, and after 12 months. The results showed that the moisture, proline content, sugar, total oxidant status (TOS), and oxidative stress index (OSI) levels were unaffected by honey type. Over time, there was a decrease in moisture, pH, proline content, diastase number, sugar, total phenolic content (TPC), total antioxidant status (TAS), and catalase activity, alongside an increase in the electrical conductivity, hydroxymethylfurfural (HMF), free acidity, TOS, and OSI levels. The packaging type did not influence the moisture, pH, electrical conductivity, proline content, diastase number, sugar, HMF, TPC, TAS, TOS, OSI, or catalase activity levels. The findings suggest that storing pine, flower, and thyme honey in light- or dark-colored glass jars or tin cans for 12 months does not significantly impact these properties. However, given the reduction in TPC and TAS across all honey types and packaging methods after 12 months, further studies are needed to explore ways to maintain honey quality in this regard.

Investigating Flavonoids by HPTLC Analysis Using Aluminium Chloride as Derivatization Reagent

This is the first study to report on high performance thin layer chromatography (HPTLC) generated spectrophotometric data to systematically capture flavonoid compounds using optimized derivatization with either AlCl3 or NaNO2-AlCl3-NaOH as visualisation reagents. While the traditional AlCl3 colorimetric method using UV-Vis analysis provides valuable insights into the presence of flavonoids and allows derivation of the total flavonoid content (TFC) of a sample, HPTLC fingerprints obtained after spraying with AlCl3 or NaNO2-AlCl3-NaOH enable the visualization of the various flavonoids present in a sample based on their respective absorption shifts, thus complementing the traditional TFC assay. In this study, 40 different flavonoids representing different classes (flavonols, flavanolols, flavan-3-ol, flavones, flavanones, and isoflavonoids) were analysed. Upon derivatization with AlCl3 most of the investigated flavonoids recorded bathochromic shifts, yielding characteristic λmax values between 370 and 420 nm, while spraying with NaNO2-AlCl3-NaOH triggered hyperchromic shifts, and thus an increase in absorbance intensity in flavonoids with particular substitution patterns. A few non-flavonoid components with structural similarities to flavonoids (e.g., rosmarinic acid, gallic acid, aspirin, salicylic acid) served as the negative control in this study to determine whether the derivatization reagents allowed exclusive detection of flavonoids. The method was then applied to the analysis of flavonoid containing supplements as well as red clover honey to demonstrate the method's application in the analysis of natural products.

The Potential Health Benefits of Gallic Acid: Therapeutic and Food Applications

Gallic acid (GA), a phenolic acid found in fruits and vegetables, has been consumed by humans for centuries. Its extensive health benefits, such as antimicrobial, antioxidant, anticancer, anti-inflammatory, and antiviral properties, have been well-documented. GA's potent antioxidant capabilities enable it to neutralize free radicals, reduce oxidative stress, and protect cells from damage. Additionally, GA exerts anti-inflammatory effects by inhibiting inflammatory cytokines and enzymes, making it a potential therapeutic agent for inflammatory diseases. It also demonstrates anticancer properties by inhibiting cancer cell growth and promoting apoptosis. Furthermore, GA offers cardiovascular benefits, such as lowering blood pressure, decreasing cholesterol, and enhancing endothelial function, which may aid in the prevention and management of cardiovascular diseases. This review covers the chemical structure, sources, identification and quantification methods, and biological and therapeutic properties of GA, along with its applications in food. As research progresses, the future for GA appears promising, with potential uses in functional foods, pharmaceuticals, and nutraceuticals aimed at improving overall health and preventing disease. However, ongoing research and innovation are necessary to fully understand its functional benefits, address current challenges, and establish GA as a mainstay in therapeutic and nutritional interventions.

Physicochemical Properties, Antioxidant Activity, and High-Performance Thin-Layer Chromatography Profiling of Propolis Samples from Western Australia

This study reports on the physicochemical and antioxidant properties of propolis samples from various regions across Western Australia and identifies some phenolic constituents using high-performance thin-layer chromatography (HPTLC). Total phenolic content (TPC) was determined using a modified Folin-Ciocalteu assay, and antioxidant activity was investigated with the Ferric Reducing Antioxidant Power (FRAP) assay and also visualised and semi-quantified by HPTLC-DPPH analysis. TPC values ranged from 9.26 to 59.3 mg gallic acid equivalent/g of raw propolis and FRAP assay data from 4.34 to 53.8 mmol Fe2+ mmol/kg of raw propolis, although some of these variations might be related to differences in extraction yields obtained with 70% ethanol. The presence of luteolin, taxifolin, naringenin, and 4-hydroxyphenylacetic acid was confirmed based on a comprehensive, validated matching approach against an HPTLC-derived database. The findings of the study highlight the importance of future research on the chemical composition and bioactivity of Western Australian propolis.

Preliminary Identification and Quantification of Individual Polyphenols in Fallopia japonica Plants and Honey and Their Influence on Antimicrobial and Antibiofilm Activities

Fallopia japonica (FJ), an invasive plant species known for its rich bioactive compounds, has been used for centuries in traditional Chinese medicine. Despite its significant beekeeping potential, this aspect of FJ remains underexplored. This research aims to investigate the antimicrobial and antibiofilm properties of FJ plants and honey. Notably, this study is the first to identify individual phenolic compounds in both FJ plant tissues and FJ honey, highlighting resveratrol as a marker of FJ honey. The study tested inhibitory activity against seven bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Salmonella enteritidis, and the yeast Candida albicans. Disk diffusion and microdilution methods were used to assess antimicrobial activity, while the crystal violet staining test evaluated antibiofilm activity. Results showed that FJ plant tissues and honey exhibited strong inhibition, particularly against Gram-negative bacterial strains. The most significant inhibition of biofilm formation, by both FJ plant tissues and honey, was observed against Staphylococcus aureus and Escherichia coli. A significant positive correlation was found between antimicrobial activity and individual polyphenols, especially resveratrol. The antibacterial and antibiofilm potential of FJ plant tissues and honey suggests promising applications in sustainable beekeeping. Further research is necessary to evaluate the bioactive compounds found in FJ honey and their health effects.

Diversity in Pyracantha fortuneana fruits maturity stages enables discrepancy in the phenolic compounds, antioxidant activity, and tyrosinase inhibitory activity

Pyracantha fortuneana (P. fortuneana) fruit is a wild fruit that is popular because of its delicious taste and numerous nutrients, and phenolic compounds are considered to be the main bioactive components in P. fortuneana fruits. However, the relationship between phenolic compounds and their antioxidant and tyrosinase (TYR) inhibitory activities during the ripening process is still unclear. The study compared the influence of the five developmental stages on the accumulation of phenolic compounds, antioxidant activity, and TYR inhibitory activity in the fruits of P. fortuneana. The compounds were identified by offline two-dimensional liquid chromatography-electrochemical detection (2D-LC-ECD) combined with liquid chromatography-tandem mass spectrometry, and the main active ingredients were quantified. The results showed that stage II had higher total phenolic and flavonoid content, as well as higher antioxidant and TYR inhibitory activity, but the total anthocyanin content was lowest at this stage. A total of 30 compounds were identified by 2D-LC-ECD. Orthogonal partial least squares discriminant analysis screened out six major potential markers, including phenolic acids, procyanidins, and flavonoids. In addition, it was found that caffeoylquinic acids, procyanidins, and flavonoids were higher in stage II than in stages I, III, IV, and V, whereas anthocyanins accumulated gradually from stages III to V. Therefore, this study suggests that the changes in antioxidant and TYR inhibitory activities of P. fortuneana during the five developmental stages may be due to the transformation of procyanidins, caffeoylquinic acids, and phenolic glycosides into other forms during the fruit maturation process. Practical Application: Differences in chemical constituents, antioxidant, and tyrosinase inhibitory activities in fruit maturity stages of P. fortuneana were elucidated to provide reference for rational harvesting and utilization of the fruits and their bioactive components. These findings are expected to provide a comprehensive assessment of the bioactive profile and guide the food industrial production.

Estrogenic Isoflavones in Clover Plants, Flower Nectar, Unripe Honeys and Mature Honeys: A Natural Biochemical Transformation of Isoflavones by Honeybees

This study is the first to report on the presence of oestrogenic compounds in different clover flower nectar samples, in bee-deposited nectars collected from hive combs (unripe honey) and in mature honeys harvested from the same hives. The clover species investigated were two red clover (Trifolium pratense) cultivars, bred specifically for high isoflavone content, alongside a sainfoin (Onobrychis viciifolia) and a purple clover (T. purpureum) cultivar. A total of eight isoflavones, four of them non-glycosidic (biochanin A, formononetin, genistein and daidzein) the others glycosidic (sissotrin, ononin, genistin and daidzin), were targeted for identification and quantification in this study using high-performance thin-layer chromatography (HPTLC). Leaves and flower bracts of the clover samples were also investigated. Different isoflavone profiles were found across the four clover species and also in the different samples collected from each species indicating that, most likely due to the activity of honeybee (Apis mellifera) salivary enzymes, biochemical conversions take place when these bioactive compounds transition from flower nectar into ripe honey. Among the four investigated clover species, the two red clover cultivars, including their honeys, were found to contain higher levels of estrogenic compounds compared to other two cultivars.

Antioxidant Activity, Physicochemical and Sensory Properties of Stingless Bee Honey from Australia

This study reports on the physicochemical and sensory attributes, total phenolic content, and antioxidant activity of 36 honey samples produced by two different stingless bee species (Tetragonula carbonaria and Tetragonula hockingsi) from Australia. The findings reveal moisture content across all samples ranges from 24.9% to 30.8% (w/w), electrical conductivity from 1.02 to 2.15 mS/cm, pH levels between 3.57 and 6.54, soluble solids from 69.2 to 75.1 °Brix, trehalulose concentrations from 6.20 to 38.2 g/100 g, fructose levels from 7.79 to 33.4 g/100 g, and glucose content from 3.36 to 26.8 g/100 g. Sucrose was undetectable in all investigated samples. In a sensory analysis involving 30 participants, Australian stingless bee honey was perceived as having a more pronounced sourness compared with New Zealand Manuka honey. The study reveals considerable variability in the composition of Australian stingless bee honey, influenced by factors such as floral availability, geographical origin, and time of harvest. It also demonstrates the presence of phenolic compounds and antioxidant activity in stingless bee honey, underlining their potential as a natural source of antioxidants. All investigated samples contain trehalulose, which supports the findings of other recent studies that propose this unusual disaccharide as a marker compound of stingless bee honey.

Determination of Physicochemical Characteristics, Phytochemical Profile and Antioxidant Activity of Various Clover Honeys

This paper reports on some physicochemical and phytochemical characteristics (i. e. pH, electrical conductivity, colour, moisture content, total phenolic content, sugar profile) and in vitro antioxidant activity of honeys harvested from five legume species, red clover (Trifolium pratense), balansa clover (T. michelianum), Persian clover (T. resupinatum), purple clover (T. purpureum) and sanfoin, also known as holy clover (Onobrychis viciifolia), that were grown in enclosed shade houses to ensure that the honeys' characteristics are reflective of a truly monofloral honey. Glucose and fructose, determined via High-Performance Thin-Layer Chromatography (HPTLC) analysis, were found as the main sugars in all investigated honeys with the ratio of fructose to glucose ranging from 1 : 1.2 to 1 : 1.6. The honeys' pH values ranged from 3.9 to 4.6 which met Codes Alimentarius (CA) requirements. The moisture content was found to be between 17.6 and 22.2 % which in some cases was slightly higher than CA requirements (≤20 %). The honeys' colour values, prior and after filtration, were between 825.5-1149.5 mAU and 532.4-824.8 mAU respectively, illustrating golden yellow to deep yellow hues. The total phenolic content (TPC) of the honeys was determined using a modified Folin-Ciocalteu assay. Their antioxidant activity was captured by the Ferric Reducing-Antioxidant Power (FRAP) assay as well as HPTLC analysis coupled with 2,2-diphenyl-1-picrylhydrazyl (DPPH) derivatisation. The highest total phenolic content was found in red clover honey (45.4 mg GAE/100 g) whereas purple clover honey showed the highest level of activity in the FRAP assay (7.3 mmol Fe2+/kg). HPTLC-DPPH analysis of the honeys' organic extracts demonstrated the presence of various bioactive compounds that contribute to their overall antioxidant activity. This study developed a methodology for producing monofloral clover honeys in a space limited, enclosed production system, which allowed to collate important baseline data for these honeys that can serve as the foundation for their potential future development into commercial honeys, including honeys that can be used for medicinal purposes.

Honey as a Natural Nutraceutical: Its Combinational Therapeutic Strategies Applicable to Blood Infections-Septicemia, HIV, SARS-CoV-2, Malaria

Honey is a natural substance that has existed alongside humanity since the time of antiquity, acting then as a source of nutrition, as well as a source of medicinal aid for people. Ancient civilizations from multiple nations of the world, from ancient China to ancient Greece and Egypt, utilized the supposed healing properties of honey to treat lacerations and wounds, as well as for internal pathologies such as intestinal disease. At present, honey has entered the modern scientific research program in search of novel antibiotics. In recent research, honey has demonstrated its potential use for static and/or cidal effects on microbial strains which are becoming resistant to chemical antibiotics. Additionally, the use of honey as an agent of treatment for more severe infections, namely blood infections pertaining to septicemia, HIV, and SARS-CoV-2, as well as parasitic infections such as malaria, have also been investigated in recent years. In this article, the literature has been reviewed on some of the therapeutic properties of natural nutraceutical honey, where it has been observed to act as a potential ameliorating agent; reducing the severity of such conditions that may amplify a disease, as well as reducing the progression of the disease and its symptoms.

Differential Apoptotic Effects of Bee Product Mixtures on Normal and Cancer Hepatic Cells

Most effective anticancer drugs normally generate considerable cytotoxicity in normal cells; therefore, the preferential activation of apoptosis in cancer cells and the reduction of toxicity in normal cells is a great challenge in cancer research. Natural products with selective anticancer properties used as complementary medicine can help to achieve this goal. The aim of the present study was to analyze the effect of the addition of bee products [propolis (PR) or royal jelly (RJ) or propolis and royal jelly (PR+RJ), 2-10%] to thyme (TH) and chestnut honeys (CH) on the differential anticancer properties, mainly the cytotoxic and pro-apoptotic effects, in normal and cancer hepatic cells. The cytotoxic effects of samples were analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay (0-250 mg/mL) and the effects on apoptosis were analyzed using cell cycle analysis, TdT-dUTP terminal nick-end labeling (TUNEL) assay, DR5 (Death Receptor 5) and BAX (BCL-2-Associated X) activation, and caspases 8, 9, and 3 activities. Both honey samples alone and honey mixtures had no or very little apoptotic effect on normal cells. Antioxidant honey mixtures enhanced the apoptotic capacity of the corresponding honey alone via both extrinsic and intrinsic pathways. Of all the samples, chestnut honey enriched with 10% royal jelly and 10% propolis (sample 14, CH+10RJ+10PR) showed the highest apoptotic effect on tumor liver cells. The enrichment of monofloral honey with bee products could be used together with conventional anticancer treatments as a dietary supplement without side effects. On the other hand, it could be included in the diet as a natural sweetener with high added value.