Chemical Characterization, α-Glucosidase, α-Amylase and Lipase Inhibitory Properties of the Australian Honey Bee Propolis

Bioactive Polyphenolic Compounds from Propolis of Tetragonula carbonaria in the Gibberagee Region, New South Wales, Australia

Stingless bee propolis has emerged globally as a new source of bioactive molecules that can advance human health. However, limited research has been conducted on Australian stingless bee propolis. This study investigated the chemical composition and biological activity of the propolis produced by the stingless bees Tetragonula carbonaria from Gibberagee, a distinct region of New South Wales state in Australia. Using bioassay-guided fractionation, twelve compounds were isolated, including six A-ring methylated flavonoids. Nine of these compounds demonstrated strong scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radicals, with five exhibiting greater potency than vitamin C. Chemical structures of seven additional minor flavonoids were determined through an intensive MS/MS data analysis. In silico screening of these 19 compounds revealed that all, except for gallic acid, displayed a higher binding affinity to α-glucosidase than the antidiabetic drug, voglibose. This study showed that the Gibberagee stingless bee propolis is a promising source for nutraceutical and cosmeceutical applications owing to its strong antioxidant and antidiabetic properties. The unique profile of A-ring C-methylated flavonoids potentially provides valuable insights into its botanical origin.

Alsfouk B, Eddamsyry B, Khamar H, Zair T, Alaoui El Belghiti M. Chemical composition, antimicrobial, and antioxidant properties of essential oils from Artemisia herba-alba asso. and Artemisia huguetii caball. from Morocco: in vitro and in silico evaluation

Introduction

Morocco is home to a remarkable diversity of flora, including several species from the Artemisia genus. This study aims to thoroughly examine the chemical composition of essential oils derived from Artemisia species and assess their antibacterial and antioxidant properties through in vitro experiments and in silico simulations.

Methods

Samples of Artemisia herba-alba Asso. were collected from Boulemane and Ifrane in Morocco, while Artemisia huguetii Caball. was sampled from Tata, representing regions of the Central Middle Atlas and Western Anti-Atlas. Essential oils were extracted using hydrodistillation, and their chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Antibacterial and antifungal activities were evaluated, and antioxidant properties were assessed using the DPPH assay. In silico predictions of antibacterial and antioxidant activities were performed using computational models.

Results

The extraction yields varied depending on the geographical origin, ranging from 1.54% to 2.78%. GC-MS analysis revealed significant differences in the chemical composition of the oils from different Artemisia species and regions, with a notable prevalence of oxygenated monoterpenes. Specifically, the oil from Boulemane was rich in thujone, the oil from Ifrane was predominantly composed of camphor, and the oil from Tata contained both camphor and thujone. The oils exhibited stronger antifungal than antibacterial properties, with Enterobacter cloacae strains showing high sensitivity, with minimum inhibitory concentrations (MIC) of approximately 12.5 mg/mL. The Boulemane oil of A. herba-alba displayed the highest antioxidant activity, effectively inhibiting DPPH at a concentration of 13.501 μg/mL.

Discussion

The in silico simulations predicted that the primary compounds in these essential oils, such as davanone, eucalyptol, camphor, and thujone, would exhibit potent antibacterial and antioxidant properties. These compounds were found to have favorable ADMET characteristics, including good blood-brain barrier permeability, gastrointestinal absorption, and skin penetration. Molecular docking studies revealed strong interactions between these compounds and key target proteins, such as NADPH-dependent catalase and dihydrofolate reductase. The stability of the protein-ligand complexes was confirmed by molecular dynamics, with davanone showing a significant impact. Overall, this study provides a comprehensive understanding of the biological potential of Artemisia essential oils, highlighting davanone as a promising molecule for medicinal or pharmaceutical applications.

Enzyme Inhibitory, Physicochemical, and Phytochemical Properties and Botanical Sources of Honey, Bee Pollen, Bee Bread, and Propolis Obtained from the Same Apiary

Bee products are an important source of nutrients and bioactive phytochemicals. This study aimed to determine the chemical composition (proximate composition, general phytochemical composition, sugar, and phenolic profiles) of four different products (honey, bee pollen, bee bread, and propolis), obtained from the same apiary, as well as to assess their biological activity through antioxidant and enzyme inhibition assays (α-amylase, α-glucosidase, lipase, AchE, neuraminidase, angiotensin-converting enzyme, urease, trypsin, tyrosinase, carbonic anhydrase, thioredoxin reductase, adenosine deaminase). Clear differences were observed among the samples in terms of both chemical composition and biological activity. The analysis revealed that bee pollen exhibited the highest carbohydrate content (87.9%), while propolis was identified as the richest source of phenolic compounds (14,858.9 mg/kg) among the analyzed samples. Propolis exhibited the highest biological activity in all applied antioxidant assays (CUPRAC, DPPH•, and ABTS•+) and in most enzyme inhibition assays. Notably, the α-glucosidase inhibition activity of propolis was comparable to that of the reference standard. In addition, honey exhibited remarkable trypsin inhibition, also comparable to the applied standard. These findings highlight the diverse bioactivities of hive products, which could play a key role in promoting health and preventing diseases.

Isolation and purification of polyphenols, hypoglycemic and hypolipidemic and active constituent analysis of walnut septum polyphenols

Walnut septum is rich in polyphenolic substances, but the hypoglycaemic and hypolipidemic effects of walnut septum polyphenols (WSP) and the main active compounds responsible for these effects are still unknown. In the present study, WSP was firstly extracted, and then purified using D101 macroporous resin, and the purity of WSP obtained was 87.36 %. WSP inhibited the activity of α-glucosidase and pancreatic lipase with IC50 values of 36.2 μg/mL and 155.9 μg/mL, respectively. Furthermore, WSP increased glucose consumption and decreased oxidative stress in insulin-resistant C2C12 cells, as well as inhibited lipid accumulation in 3 T3-L1 adipocytes. Eight naturally active ligands for α-glucosidase and pancreatic lipase were identified from WSP by affinity ultrafiltration combined with liquid chromatography-mass spectrometry analytical methods. Further molecular docking showed strong binding between these eight ligands and the enzyme. The results of the study lay a scientific foundation for the development of walnut septum as a functional food for hypoglycemic and hypolipidemic.

Novel carbazole-oxadiazole derivatives as anti-α-glucosidase and anti-α-amylase agents: Design, synthesis, molecular docking, and biological evaluation

To find novel inhibitors of α-glucosidase and α-amylase, a series of new carbazole-oxadiazole derivatives (6a-6n) were prepared, and screened for their anti-α-glucosidase and anti-α-amylase effects. Most of the tested derivatives showed different degrees of α-glucosidase and α-amylase inhibitory activity (IC50: 21.39 ± 0.69-92.05 ± 1.54 μM, 45.53 ± 1.50-126.14 ± 6.33 μM, respectively) compared to the standard acarbose (IC50: 427.00 ± 9.56 μM, 24.68 ± 1.10 μM, respectively). Thereinto, 6c (IC50 = 21.39 ± 0.69 μM) displayed the most effective anti-α-glucosidase activity and 6e presented the best anti-α-amylase activity with an IC50 value of 45.53 ± 1.50 μM. Lineweaver-Burk plot analysis suggested that 6c and 6e behaved as mixed α-glucosidase inhibitor and mixed α-amylase inhibitor, respectively. The results of circular dichroism, atomic force microscope, and molecular docking simulation exposed interaction mechanisms between two preferred compounds (6c and 6e) and their corresponding enzymes. Combined with the possible properties of reducing the elevation in postprandial blood glucose, oral activity, positive bioavailability, and low cytotoxicity of 6c and 6e, it could be concluded that the target derivatives may be able to act as lead molecules for the development of new hypoglycemic agents.

Intake of imidacloprid in lethal and sublethal doses alters gene expression in Apis mellifera bees

Bees are important pollinators for ecosystems and agriculture; however, populations have suffered a decline that may be associated with several factors, including habitat loss, climate change, increased vulnerability to diseases and parasites and use of pesticides. The extensive use of neonicotinoids, including imidacloprid, as agricultural pesticides, leads to their persistence in the environment and accumulation in bees, pollen, nectar, and honey, thereby inducing deleterious effects. Forager honey bees face significant exposure to pesticide residues while searching for resources outside the hive, particularly systemic pesticides like imidacloprid. In this study, 360 Apis mellifera bees, twenty-one days old (supposed to be in the forager phase) previously marked were fed syrup (honey and water, 1:1 m/v) containing a lethal dose (0.081 μg/bee) or sublethal dose (0.00081 μg/bee) of imidacloprid. The syrup was provided in plastic troughs, with 250 μL added per trough onto each plastic Petri dish containing 5 bees (50 μL per bee). The bees were kept in the plastic Petri dishes inside an incubator, and after 1 and 4 h of ingestion, the bees were euthanised and stored in an ultra-freezer (-80 °C) for transcriptome analysis. Following the 1-h ingestion of imidacloprid, 1516 genes (73 from lethal dose; 1509 from sublethal dose) showed differential expression compared to the control, while after 4 h, 758 genes (733 from lethal dose; 25 from sublethal) exhibited differential expression compared to the control. All differentially expressed genes found in the brain tissue transcripts of forager bees were categorised based on gene ontology into functional groups encompassing biological processes, molecular functions, and cellular components. These analyses revealed that sublethal doses might be capable of altering more genes than lethal doses, potentially associated with a phenomenon known as insecticide-induced hormesis. Alterations in genes related to areas such as the immune system, nutritional metabolism, detoxification system, circadian rhythm, odour detection, foraging activity, and memory in bees were present after exposure to the pesticide. These findings underscore the detrimental effects of both lethal and sublethal doses of imidacloprid, thereby providing valuable insights for establishing public policies regarding the use of neonicotinoids, which are directly implicated in the compromised health of Apis mellifera bees.

Propolis in the management of cardiovascular disease

BACKGROUND

Propolis is a resinous compound that is obtained from honey bees. It consists of numerous chemical constituents that impart different therapeutic action. The heart is the core of the body and cardiovascular disease (CVD) is a burden for the human being. This article emphasizes how propolis is fruitful in the management of various CVDs.

SCOPE AND APPROACH

This review focuses on how various constituents of the propolis (such as terpenes, flavonoids, phenolics, etc.) impart cardio protective actions.

KEY FINDING AND CONCLUSION

With the support of various clinical trials and research outcomes, it was concluded that propolis owns niche cardio protective properties that can be a boon for various cardiac problems (both in preventive and therapeutic action) such as atherosclerosis, excessive angiogenesis, hypertension, and many more.

Antiobesity effect of healthy food crops and functional foods: A systematic review of their mechanisms

Diet is a modifiable risk factor in the prevention and management of obesity, and various foods have the potential to aid in obesity management by modulating different pathways involved in the disease's pathology. We performed a systematic review of literature, using CINAHL, PubMed, and Google Scholar, focusing on the antiobesity potential of foods crops and functional food products, and their mechanisms of action and clinical evidence. Sixty-four articles were identified, of which 41 investigated food crops, while 23 investigated functional products. Food crops, such as cereals, vegetables, fruits, mushrooms, seaweeds, legumes, herbs, spices, and cocoa seeds, have antiobesity effects through mechanisms such as altering the metabolism of glucolipids by inhibiting enzymes like α-amylase and α-glucosidase, stimulating the bioenergetics of thermogenic fat, modulating gut microbiota, and inhibiting lipogenesis and storage. In addition, developed functional teas, beverages, and yoghurt have antiobesity effects through similar or different mechanisms, such as enhancing energy expenditure and satiety, suppressing adipogenesis and lipolysis, improving glucose and lipid metabolism, and altering hormonal secretion. This review reemphasized the significance of food in the control of obesity, and highlights the distinct methods these explored foods exert their antiobesity effects. In conclusion, foods are safe and effective means of combating obesity without the side effects of conventional drugs, which can help inform dietary choices, assist professionals in providing more accurate advice, and also lead to better understanding of food and its effect on overall health of the public. This approach will eradicate global diseases, especially if more underutilized and indigenous food crops are extensively researched.

Identification of isobenzofuranone derivatives as promising antidiabetic agents: Synthesis, in vitro and in vivo inhibition of α-glucosidase and α-amylase, computational docking analysis and molecular dynamics simulations

Diabetes mellitus, one of the major health challenges of the 21st century, is associated with numerous biomedical complications including retinopathy, neuropathy, nephropathy, cardiovascular diseases and liver disorders. To control the chronic hyperglycemic condition, the development of potential inhibitors of drug targets such as α-glucosidase and α-amylase remains a promising strategy and focus of continuous efforts. Therefore, in the present work, a concise library of isobenzofuranone derivatives (3a-q) was designed and synthesized using Suzuki-Miyaura cross-coupling approach. The biological potential of these heterocyclic compounds against carbohydrate-hydrolyzing enzymes; α-glucosidase and α-amylase, was examined. In vitro inhibitory results demonstrated that the tested isobenzofuranones were considerably more effective and potent inhibitors than the standard drug, acarbose. Compound 3d having an IC50 value of 6.82 ± 0.02 μM was emerged as the lead candidate against α-glucosidase with ⁓127-folds strong inhibition than acarbose. Similarly, compound 3g demonstrated ⁓11-folds higher inhibition strength against α-amylase when compared with acarbose. Both compounds were tested in vivo and results demonstrate that the treatment of diabetic rats with α-amylase inhibitor show more pronounced histopathological normalization in kidney and liver than with α-glucosidase inhibitor. The Lineweaver-Burk plot revealed an uncompetitive mode of inhibition for 3d against α-glucosidase whereas compound 3g exhibited mixed inhibition against α-amylase. Furthermore, in silico molecular docking and dynamics simulations validated the in vitro data for these compounds whereas pharmacokinetics profile revealed the druglike properties of potent inhibitors.

Characterization and bioactivities of coffee husks extract encapsulated with polyvinylpyrrolidone

Coffee processing generates large amounts of residues of which a portion still has bioactive properties due to their richness in phenolic compounds. This study aimed to obtain a coffee husks extract (CHE) and to encapsulate it (ECHE) with polyvinylpyrrolidone using a one-step procedure of solid dispersion. The extraction and encapsulation yields were 9.1% and 92%, respectively. Thermal analyses revealed that the encapsulation increased the thermal stability of CHE and dynamic light scattering analyses showed a bimodal distribution of size with 81% of the ECHE particles measuring approximately 711 nm. Trigonelline and caffeine were the main alkaloids and quercetin the main phenolic compound in CHE, and the encapsulation tripled quercetin extraction. The total phenolics content and the antioxidant activity of ECHE, assayed with three different procedures, were higher than those of CHE. The antioxidant activity and the bioaccessibility of the phenolic compounds of ECHE were also higher than those of CHE following simulated gastrointestinal digestion (SGID). Both CHE and ECHE were not toxic against Alliumcepa cells and showed similar capacities for inhibiting the pancreatic α-amylase in vitro. After SGID, however, ECHE became a 1.9-times stronger inhibitor of the α-amylase activity in vitro (IC50 = 8.5 mg/mL) when compared to CHE. Kinetic analysis revealed a non-competitive mechanism of inhibition and in silico docking simulation suggests that quercetin could be contributing significantly to the inhibitory action of both ECHE and CHE. In addition, ECHE (400 mg/kg) was able to delay by 50% the increases of blood glucose in vivo after oral administration of starch to rats. This finding shows that ECHE may be a candidate ingredient in dietary supplements used as an adjuvant for the treatment of diabetes.

Potential Antidiabetic Activity of Apis mellifera Propolis Extraction Obtained with Ultrasound

Recent studies have linked phenolic compounds to the inhibition of digestive enzymes. Propolis extract is consumed or applied as a traditional treatment for some diseases. More than 500 chemical compounds have been identified in propolis composition worldwide. This research aimed to determine Mexican propolis extracts' total phenolic content, total flavonoid content, antioxidant activity, and digestive enzyme inhibitory activity (ɑ-amylase and ɑ-glucosidase). In vitro assays measured the possible effect on bioactive compounds after digestion. Four samples of propolis from different regions of the state of Oaxaca (Mexico) were tested (Eloxochitlán (PE), Teotitlán (PT), San Pedro (PSP), and San Jerónimo (PSJ)). Ethanol extractions were performed using ultrasound. The extract with the highest phenolic content was PE with 15,362.4 ± 225 mg GAE/100 g. Regarding the flavonoid content, the highest amount was found in PT with 8084.6 ± 19 mg QE/100 g. ABTS•+ and DPPH• radicals were evaluated. The extract with the best inhibition concentration was PE with 33,307.1 ± 567 mg ET/100 g. After simulated digestion, phenolics, flavonoids, and antioxidant activity decreased by 96%. In contrast, antidiabetic activity, quantified as inhibition of ɑ-amylase and ɑ-glucosidase, showed a mean decrease in enzyme activity of approximately 50% after the intestinal phase. Therefore, it is concluded that propolis extracts could be a natural alternative for treating diabetes, and it would be necessary to develop a protective mechanism to incorporate them into foods.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA .

Antiobesity Drug Discovery Research: In vitro Models for Shortening the Drug Discovery Pipeline

Obesity is a growing global health problem, leading to various chronic diseases. Despite standard treatment options, the prevalence of obesity continues to rise, emphasizing the need for new drugs. in vitro methods of drug discovery research provide a time and cost-saving platform to identify new antiobesity drugs. The review covers various aspects of obesity and drug discovery research using in vitro models. Besides discussing causes, diagnosis, prevention, and treatment, the review focuses on the advantages and limitations of in vitro studies and exhaustively covers models based on enzymes and cell lines from different animal species and humans. In contrast to conventional in vivo animal investigations, in vitro preclinical tests using enzyme- and cell line-based assays provide several advantages in development of antiobesity drugs. These methods are quick, affordable, and provide high-throughput screening. They can also yield insightful information about drug-target interactions, modes of action, and toxicity profiles. By shedding light on the factors that lead to obesity, in vitro tests can also present a chance for personalized therapy. Technology will continue to evolve, leading to the creation of more precise and trustworthy in vitro assays, which will become more and more crucial in the search for novel antiobesity medications.

Propolis and its constituents against cardiovascular risk factors including obesity, hypertension, atherosclerosis, diabetes, and dyslipidemia: A comprehensive review

Cardiovascular diseases (CVDs) are some of the major causes of death worldwide. The modern lifestyle elevates the risk of CVDs. CVDs have several risk factors such as obesity, dyslipidemia, atherosclerosis, hypertension, and diabetes. Using herbal and natural products plays a pivotal role in the treatment of different diseases such as CVDs, diabetes, and metabolic syndrome. Propolis, a natural resinous mixture, is made by honey bees. Its main components are phenolics and terpenoid compounds such as caffeic acid phenethyl ester, chrysin, and quercetin. In this review, multiple studies regarding the pharmacological impacts of propolis and its constituents with their related mechanisms of action against mentioned CVD risk factors have been discussed in detail. Here, we used electronic databases or search engines such as Scopus, Web of Science, Pubmed, and Google Scholar without time limitations. The primary components of propolis are phenolics and terpenoid compounds such as caffeic acid phenethyl ester, chrysin and quercetin. Propolis and its constituents have been found to exhibit anti-obesity, anti-hypertension, anti-dyslipidemic, anti-atherosclerosis, and anti-diabetic effects. The vast majority of studies discussed in this review demonstrate that propolis and its constituents could have therapeutic effects against mentioned CVD risk factors via several mechanisms such as antioxidant, anti-inflammatory, reducing adipogenesis, HMG-CoA reductase inhibitory effect, inhibition of the ACE, increasing insulin secretion, NO level, etc.