A New Approach for Indexing Honey for Its Heath/Medicinal Benefits: Visualization of the Concept by Indexing Based on Antioxidant and Antibacterial Activities

Combination of stem cell-derived secretome from human exfoliated deciduous teeth with Yemeni Sidr honey on cell viability and migration: an in vitro study

INTRODUCTION

Bone diseases have a profound global impact, especially when the body's innate regenerative capacity falls short in the face of extensive damage. Stem cells from human exfoliated deciduous teeth (SHEDs), discovered in 2003, offer a promising solution for tissue repair, as they self-renew naturally and are easily obtainable. Mesenchymal stem cells (MSCs), including SHEDs, are believed to promote tissue regeneration by releasing growth factors, collectively known as the secretome.

AIMS

This study explored the potential of combining SHED-derived secretome with Yemeni Sidr honey to improve osteoblast and fibroblast cell viability and migration.

MATERIALS AND METHODS

The experiment involved treating cell cultures of two types of rat cell lines - 7F2 osteoblast and BHK-21 fibroblast immortalized cells - with SHED-derived secretome and Yemeni Sidr honey. After the treatment, cell viability was measured using the MTT assay, which calculates OD at 590 nm. Additionally, the scratch assay was conducted to evaluate cell migration, and ImageJ software was used for data processing.

RESULTS

The findings indicated that combining SHED-derived secretome and Yemeni Sidr honey enhanced osteoblast and fibroblast cell viability and migration. Furthermore, the study highlighted the difference in the stimulative potential of SHED-derived secretome, Yemeni Sidr honey, and their combination, on the viability and migration of the cultured cells.

CONCLUSION

The research concludes that combining SHED-derived secretome with Yemeni Sidr honey has the potential to promote cell viability and migration in in-vitro settings. The synergistic application of these substances has been found to be more effective -when combined in a dose-dependent manner- than their counterparts. Overall, the current study serves as a foundation for further investigations to establish if the explored substance has any useful clinical applications.

Exposure to pesticide residues in honey and its potential cancer risk assessment

Honey is the most recognized natural food by-product derived from flower nectar and the upper aero-digestive tract of the honeybees. Significance of honey for its medicinal importance are well-documented in the world's oldest medical literatures. However, the current urbanization, environmental contaminations and changes in agricultural, as well as apiculture practices has led to various types of contaminations in honey. Among all, pesticide contamination has become one of the major issues worldwide. This review focuses on the recent updates concerning pesticides occurrence in honey, as well as how the repeated use and long-term exposure to honey contaminated with pesticide residues could affect the human physiological functions, possibly leading to the development of various cancers. Our findings suggests that uncontrolled use of pesticides in farming and apiculture practices leads to the occurrence of pesticides residues in honey. Therefore, regular consumption of such honey will pose a serious threat to human health, since most of the pesticides has been reported as potential carcinogens. This review will draw the attention of honey consumers, scientific communities, apiculture farmers, as well as governing bodies to strictly monitor the pesticide usage in floriculture, agriculture as well as other related practices.

Design, Preparation, and Physicochemical Characterisation of Alginate-Based Honey-Loaded Topical Formulations

Honey has widespread use as a nutritional supplement and flavouring agent. Its diverse bioactivities, including antioxidant, antimicrobial, antidiabetic, anti-inflammatory, and anticancer properties, have also made it an aspirant natural product for therapeutic applications. Honey is highly viscous and very sticky, and its acceptance as a medicinal product will require formulation into products that are not only effective but also convenient for consumers to use. This study presents the design, preparation, and physicochemical characterisation of three types of alginate-based topical formulations incorporating a honey. The honeys applied were from Western Australia, comprising a Jarrah honey, two types of Manuka honeys, and a Coastal Peppermint honey. A New Zealand Manuka honey served as comparator honey. The three formulations were a pre-gel solution consisting of 2-3% (w/v) sodium alginate solution with 70% (w/v) honey, as well as a wet sheet and a dry sheet. The latter two formulations were obtained by further processing the respective pre-gel solutions. Physical properties of the different honey-loaded pre-gel solutions (i.e., pH, colour profile, moisture content, spreadability, and viscosity), wet sheets (i.e., dimension, morphology, and tensile strength) and dry sheets (i.e., dimension, morphology, tensile strength, and swelling index) were determined. High-Performance Thin-Layer Chromatography was applied to analyse selected non-sugar honey constituents to assess the impacts of formulation on the honey chemical composition. This study demonstrates that, irrespective of the honey type utilised, the developed manufacturing techniques yielded topical formulations with high honey content while preserving the integrity of the honey constituents. A storage stability study was conducted on formulations containing the WA Jarrah or Manuka 2 honey. The samples, appropriately packaged and stored over 6 months at 5, 30, and 40 °C, were shown to retain all physical characteristics with no loss of integrity of the monitored honey constituents.

Diversity of Monofloral Honey Based on the Antimicrobial and Antioxidant Potential

This study aimed to investigate the antioxidant profile and the antimicrobial activity of four different types of monofloral honey (manuka (MH), brassica rapeseed (BH), acacia (AH), and linden honey (LH)) against some bacterial/fungal ATCC strains and some multidrug-resistant strains isolated from chronic otitis in dogs. For the characterisation of the antioxidant profile of each honey, we extracted the honey samples by hydroalcoholic extraction and analysed them in terms of total polyphenols (TPC), total flavonoids (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) using the spectrophotometric method. The antimicrobial activity was determined using the microdilution method at concentrations of 10%, 15%, and 20%, with the results expressed in OD (optical density) calculated as BIR% (bacterial inhibition rate)/MIR% (mycelial inhibition rate). The antioxidant characterisation of the analysed honey samples showed the highest antioxidant activity and concentrations of TPC and TFC in MH, followed by LH. MH was proven to be the most effective on most clinical isolates concerning the antimicrobial activity in comparison with BH, AH, and LH. Except for B. cepacia and P. vulgaris, all the clinical isolates were sensitive to the antibacterial activity of honey. Regarding the ATCC strains, MH 10% was the most effective in inhibiting all the strains tested except for P. aeruginosa. In conclusion, the efficacy classification in our study was MH > BH > AH > LH.

Potent antioxidant peptides derived from honey major protein enhance tolerance of eukaryotic cells toward oxidative stress

Honey is known for its medicinal benefits and receiving renewed attention as natural medicine. Studies on health benefits of honey attributed its antioxidant activity to phenolic compounds, but the contribution of proteins and peptides to the antioxidant activity of honey is lacking. The aim of this study was to explore the contribution of proteins and peptides to the antioxidant activity of honey, which remained obscure for decades.

Total honey proteins (THP) were isolated by dialysis method and hydrolyzed through simulated gastrointestinal digestion. The hydrolysates were fractionated using size-exclusion chromatography. The antioxidant activity was determined by using superoxide radical-scavenging, DPPH reduction and intracellular ROS assays.

THP was shown to exhibit superoxide-scavenging activity but its pepsin-hydrolysate (HP-p) showed superior scavenging activity. The HP-p produced five peptide fractions (P1~P5) when fractionated on Sephacryl S-100 size-exclusion column. The five fractions showed superoxide-scavenging activities and DPPH reducing activities, whereas the slow-eluting peptide fractions (P3 and P4) were the most potent. MALDI-TOF/MS analysis identified a pentapeptide (TSNTF) as the dominant peptide in the active fractions P3 and P4. Human colonic epithelial cells treated with P3 and P4 peptides exhibited lower intracellular ROS, when oxidative stress was induced by H2O2 or diethyl maleate (DEM), indicating strong tolerance to oxidative stress. The viabilities of human cells or yeast cells were largely decreases under oxidative stress, but treated cells with P3 and P4 showed higher viability compared with the untreated cells. The results are the first to describe a novel antioxidant peptide from honey that confer ex vivo anti-oxidative function within a complicated milieu of eukaryotic cells and pave the way for its potential as nutraceutical or therapeutic peptide for risk-reduction of oxidative-stress and related diseases.

Graphical abstract

Antioxidant HPTLC-DPPH Fingerprinting of Honeys and Tracking of Antioxidant Constituents Upon Thermal Exposure

The use of High-Performance Thin-Layer Chromatography (HPTLC) coupled with the use of DPPH* (2,2-diphenyl-1-picrylhydrazyl) as a derivatisation reagent is a novel approach to the analysis of antioxidant activity of honeys. The method facilitates the visualisation of individual constituents that contribute to the overall antioxidant activity of the honey, even if they are not yet chemically identified, and allows for the quantification of their antioxidant activity as gallic acid equivalents. The method supports a more in-depth study of the antioxidant activity of honey as it allows for a comparative analysis of the antioxidant fingerprints of honeys of different floral origin and is able to capture differences in their individual bioactive constituents. Further, it supports the tracking of changes in antioxidant activity of individual honey constituents over time upon exposure to different temperature conditions, which demonstrates the potential value of the method for in-process quality control.

Lauryl Gallate Activity and Streptococcus mutans: Its Effects on Biofilm Formation, Acidogenicity and Gene Expression

Streptococcus mutans bacterium is implicated in the pathogenesis of dental caries due to the production of biofilm and organic acids from dietary sucrose. Despite the availability of various means of prophylaxis, caries still has a high worldwide prevalence. Therefore, it is important to find new pharmaceuticals to inhibit S. mutans biofilm formation and acidogenicity. The aim of the current study was to evaluate the activity of lauryl gallate (dodecyl gallate) against S. mutans acidogenicity, the expression of biofilm-associated genes, and biofilm development on solid surfaces (polystyrene, glass). The biofilm quantities produced by S. mutans bacteria were assessed using colorimetric and optical profilometry techniques. Acidogenicity was evaluated by measuring the pH of the biofilm growth medium with microelectrode. Assessment of the expression of gene coding for glucan-binding protein B (gbpB), glucosyltranferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of F₁ protein (atpD) was carried out using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The results demonstrate the capacity of lauryl gallate to significantly inhibit S. mutans acidogenicity and biofilm development on solid surfaces, in a dose-dependent manner, compared to untreated bacteria (p < 0.05). The highest activity of lauryl gallate occurred at a concentration of 98.98 µM, at which it suppressed biofilm formation by 100% and lowered pH levels by 98%. The effect of lauryl gallate treatment on gene expression changes, as demonstrated by our RT-qPCR data, was limited to the gtfD gene only, was a significant (48%) decrease in gene expression, obtained for the biofilm-producing bacteria, while a 300% increase in fold change for the same gene occurred in the planktonic cells. It is important to note that in previous studies we showed a broader effect of related derivatives. However, a similar magnitude of difference in effects between biofilm and planktonic cells for the atpD gene was obtained after treatment with octyl gallate and reverse magnitude for the same gene after treatment with ethyl gallate. Therefore, to ascertain the possible direct or indirect effects of lauryl gallate, as well as octyl gallate and ethyl gallate, more research is needed to examine the effects on the amount of enzymes and on the enzymatic activity of the products of the affected genes that are involved in the production and maintenance of biofilm by S. mutans.

Botanical Origin, Pollen Profile, and Physicochemical Properties of Algerian Honey from Different Bioclimatic Areas

The palynological and physicochemical analysis of 62 honey samples produced in different biogeographical areas of Algeria was conducted. Results showed high variety in the botanical origin of samples and their physicochemical profile. Twenty-six samples were polyfloral honey, 30 were unifloral honey from different botanical sources such as Eucalyptus, Citrus, Apiaceae, Punica, Erica, Rosmarinus, Eriobotrya, or Hedysarum, and 6 were characterized as honeydew honey. Pollen analysis allowed the identification of 104 pollen types belonging to 51 botanical families, whereas the physicochemical profile showed important variations between samples. Multivariate techniques were used to compare the characteristics of samples from different biogeographical areas, showing significant differences between humid-area samples, located in the northeast of the country, and samples taken in semiarid, subhumid, and arid zones. Principal-component analysis (PCA) extracted nine components explaining 72% of data variance, being 30%, the sum of Component 1 and Component 2. The plot of both components showed samples grouped upon botanical and geographical origin. The results of this paper highlighted the great variability in honey production of Algeria, evidencing the importance of honey characterization to guarantee authenticity and to valorize local production.

Correlation between cytotoxicity in cancer cells and free radical-scavenging activity: In vitro evaluation of 57 medicinal and edible plant extracts

Cancer is a complex interaction among multiple signaling pathways involving a variety of target molecules. Cancer causes morbidity and mortality in millions of people worldwide, and due to its prevalence, the discovery of novel anticancer drugs is urgently required. Nature is considered an important source of the discovery of anticancer treatments, and many of the cytotoxic medicines in clinics today are derived from plants and other natural sources. Reactive oxygen species (ROS) induce a variety of human cancers, and antioxidants or scavengers are used to counteract them. The current study reports on the screening of extracts from 57 plants that are used in the galilee district as a food and/or for traditional medicine. Investigating the free radical scavenging capacity and these plants, and their cytotoxicity, may prove helpful to high-throughput screening projects that use antioxidants and cytotoxic natural products. The current study assessed the correlation between free radical scavenging and cytotoxicity. Correlational analysis is important for increasing the efficiency of the screening process. In the present study, free radical scavenging was assessed using a DPPH assay, while cytotoxicity was measured using a XTT assay. A total of 9 extracts were indicated to exhibit EC₅₀ values <250 µg/ml, and 4 others exhibited a high antioxidant content, with EC₅₀ values, for free radical scavenging, of <0.5 µg/ml. An in-depth analysis of the results revealed that the extracts of plants that exhibit an EC₅₀ of free radical scavenging ≤10 µg/ml show a degree of enrichment toward increased cytotoxicity. It is recommended that future studies test the validity of the conclusions of the current study on other cancer cell-lines, and isolate and identify the bioactive agents that are found in the most cytotoxic extracts of plants.

Suppressive Effects of Octyl Gallate on Streptococcus mutans Biofilm Formation, Acidogenicity, and Gene Expression

The accumulation of biofilm by Streptococcus mutans bacteria on hard tooth tissues leads to dental caries, which remains one of the most prevalent oral diseases. Hence, the development of new antibiofilm agents is of critical importance. The current study reports the results from testing the effectiveness of octyl gallate (C8-OG) against: (1) S. mutans biofilm formation on solid surfaces (polystyrene, glass), (2) acidogenicity, (3) and the expression of biofilm-related genes. The amount of biofilm formed by S. mutans bacteria was evaluated using the colorimetric method and optical profilometry. The pH of the biofilm growth medium was measured with microelectrode. A quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to assess the expression of genes encoding glucan binding protein B (gbpB), glucosyltransferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of the F₁ protein (atpD). The results show that C8-OG significantly diminished biofilm formation by exposed S. mutans on solid surfaces and suppressed acidogenicity in a dose-dependent manner, compared to unexposed bacteria (p < 0.05). The C8-OG concentration of 100.24 µM inhibited S. mutans biofilm development on solid surfaces by 100% and prevented a decrease in pH levels by 99%. In addition, the RT-qPCR data demonstrate that the biofilm-producing bacteria treated with C8-OG underwent a significant reduction in gene expression in the case of the four genes under study (gbpB, gtfC, gtfD, and atpD), and there was a slight decrease in expression of the gtfB gene. However, C8-OG treatments did not produce significant expression change compared to the control for the planktonic cells, although there was a significant increase for the atpD gene. Therefore, C8-OG might be a potent antibiofilm and/or anticaries agent for oral formulations that aim to reduce the prevalence of dental caries.

Phytochemical Composition and Biological Activities of Wild Scolymus maculatus L

Background: The wild population of spotted golden thistle, Scolymus maculatus, which belongs to the Compositae family, is believed to be one of the multi-curative wild plants mentioned in Flora Palaestina. This study aims to disclose the phytochemical composition, antioxidant potential, and antimicrobial activity of wild S. maculatus collected from the farms of Kabul, a village in northwest Galilee, for the first time. Methods: The phytochemical components of crude S. maculatus extracts from methanol, ethyl acetate, and n-hexane solvents were separated and identified using gas chromatography-mass spectrometry (GC-MS) in the electron impact (EI) mode. The free radical scavenging of the plant extracts was measured by DPPH assay. The microdilution test was used to determine the minimum inhibitory concentrations (MICs) of different S. maculatus extracts and to evaluate their antimicrobial activities. Results: Thirty-two phytochemicals were found in S. maculatus extracts including stigmasterol, γ-sitosterol, lupeol, lupeol acetate, and β-amyrin. Phytochemicals, such as 2-linoleoylglycerol, γ-sitosterol, β-amyrin, lupeol, (3α)-12-oleanen-3-yl acetate, and lupenyl acetate, were found to dominate the methanol extract. Most of these compounds were also observed in ethyl acetate and n-hexane extracts, but at different levels, in addition to some other minor compounds. The various extracts were investigated for their antioxidant and antimicrobial activity. The ethanolic and the methanolic extracts were shown to exhibit the highest free radical scavenging by DPPH assay with a half-maximally effective concentration (EC₅₀) of 0.37 and 0.65 mg/mL respectively, while the other three extracts (aqueous, ethyl acetate and n-hexane) were less active and their EC₅₀ (effective concentration at which DPPH radical was scavenged by 50%) were above 1.0 mg/mL. Moreover, MICs were determined to be effective against Staphylococcus aureus, Salmonella typhimurium, and Candida albicans microorganisms. Ethyl acetate and the ethanolic extracts are active against the three types of microorganisms at a minimum inhibitory concentration (MIC) of 0.5 mg/mL, while aqueous and the n-hexane extracts are inactive against Salmonella typhimurium. Conclusions: The results show that S. maculatus extracts are a rich source of compounds that can play an important role in human health, and in a broader context, in the treatment of various diseases, such antimicrobial and antioxidant-related ailments.

Inhibitory Effects of Ethyl Gallate on Streptococcus mutans Biofilm Formation by Optical Profilometry and Gene Expression Analysis

This study aimed to test the effectiveness of ethyl gallate (EG) against S. mutans biofilm formation on solid surfaces (polystyrene, glass) and acidogenicity, and to examine the effect on expression of related genes. The biofilm that is formed by S. mutans bacteria was evaluated using colorimetric assay and optical profilometry, while the pH of the biofilm growth medium was measured with microelectrode. The expression of genes encoding glucan binding protein B (gbpB), glucosyltranferases B, -C, -D (gtfB, -C, -D) and F-ATPase (atpD, atpF) was assessed using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). It was revealed that all of the EG concentrations significantly suppressed S. mutans biofilm build-up on polystyrene and glass surfaces, and inhibited acidogenicity, in a dose-dependent manner, compared to the activity of untreated bacteria (p < 0.05). The highest concentration of EG (3.53 mM) reduced biofilm formation on polystyrene and glass surfaces by 68% and more than 91%, respectively, and prevented a decrease in pH levels by 95%. The RT-qPCR data demonstrate that the biofilm-producing bacteria treated with EG underwent significant gene expression changes involving the gtfC (a 98.6 increase in fold change), gtfB gene (a 47.5 increase in fold change) and the gbpB gene (a 13.8 increase in fold change). However, for the other genes tested (gtfD, atpD and atpF), the EG treatments did not produce significant expression change compared to the control. EG produced significant gene expression change in three genes—gtfC,gtfB, and gbpB; it has the capacity to inhibit S. mutans biofilm formation on solid surfaces (polystyrene, glass), as well as acidogenicity. Therefore, EG might be used as an antibiofilm and/or anticaries agent for oral formulations in order to reduce the prevalence of dental caries.