Compounds In Propolis Research Articles

An effective concentration of propolis extract to inhibit the activity of Streptococcus mutans glucosyltransferase enzyme

Background: According to Riset Kesehatan Dasar (Riskesdas) (2013) and the World Health Organisation (WHO), caries is still a global problem and highly prevalent in Indonesia. Caries is mainly caused by Streptococcus mutans with virulence factors known as glucosyltransferase (GTF). The GTF enzyme contribute to the pathogenesis of caries by converting sucrose to fructose and glucan, which are then used in the formation of biofilms and dental plaques. Natural propolis compounds containing flavonoids, terpenoids, saponins and tannins, can inhibit GTF enzyme activity. Purpose: This study aimed to determine an effective concentration of propolis extract for inhibiting the S. mutans GTF enzyme activity. Methods: This study used propolis extract at 14 μg/ mL, 16 μg/m and 1 μg/mL to determine the inhibitory effect on S. mutans GTF enzyme activity. The GTF enzyme were obtained from the supernatant from S. mutans culture centrifugation. The GTF enzyme activity was measured using high-performance liquid chromatography (HPLC) to calculate the fructose level. Results: The mean fructose concentration at 14 μg/mL, 16 μg/mL, and 18μg/mL were 3.31%, 1.56%, and 0.29%, respectively. Conclusion: The most effective concentration of propolis extract for inhibiting the effect of S. mutans GTF enzyme activity is 14 μg/mL.

Determination of antimicrobial and anti-quorum sensing activities of water and ethanol extracts of propolis

Quorum Sensing is a special system between bacteria to communicate with the signal molecules. Propolis is a resin collected from plants by honey bees. The present study examined anti-quorum sensing and antimicrobial activities of water and ethanol extracts of propolis. The antimicrobial activities of the propolis extracts were studied against Escherichia coli ATCC 25922 Gram (-), Listeria monocytogenes ATCC 7644, Streptococcus mutans CNCTC 8/77, Staphylococcus aureus ATCC 25923 Gram (+), Candida albicans ATCC 10239 (yeast) by the well diffusion method. Anti-quorum sensing activity, violacein inhibition activity, and anti-swarming activity were studied using Chromobacterium violaceum CV026 and C. violaceum ATCC 112472, and Pseudomonas aeruginosa (PA01) respectively. Both propolis extracts were detected antibacterial activity against Gram (+) bacteria and Candida albicans. However, antibacterial activity against Gram (-) bacteria were not observed. While the antimicrobial activity of water extract propolis was determined more effectively than ethanol extract, anti-quorum sensing and anti-swarming activities less effective. It was also detected that both extracts display violacein inhibition. It was revealed that the antimicrobial, anti-quorum sensing, anti-swarming activity depended on the dose of propolis extracts. Thirty-six phenolic compounds were analysed of propolis extract by HPLC-DAD. The amount and presence of phenolic compounds in the ethanol extract were more than the water extract apart from benzoic acid, cinnamic acid, syringic acid, (±) epigallocatechin, vitexin, rutin, and trans-chalcone. Consequently, the study put forward that the phenolic compounds of propolis have antibacterial, anti- quorum sensing, violacein inhibition, and anti-swarming activities changing depend on directly the extraction solvent and phenolic compounds.

Propolis supplementation affects performance, intestinal morphology, and bacterial population of broiler chickens

A meta-analysis was conducted to examine the effect of supplementing the diet of broiler chickens with propolis on growth, bacterial population of the intestine, antiviral serum concentration, intestinal morphology, and digestive enzyme activities in broiler chickens. Forty peer-reviewed articles that had been published between 2003 and 2019 were identified using the PRISMA protocol and included in the study. Data were analysed with mixed model methodology, in which the studies were considered random effects, whereas the level of supplemental propolis was considered a fixed effect. Responses to propolis supplementation in bodyweight (BW) and average daily gain (ADG) were quadratic, but average daily feed intake (ADFI) was not affected. Propolis supplementation improved feed conversion ratio (FCR) significantly as a linear function of the level of supplement. The optimum level of supplementation was between 256 and 262 mg/kg feed and produced maximum ADG and final BW. There was a tendency for mortality to decrease because of propolis supplementation. Propolis had no detectable effect on serum antiviral concentration, intestinal bacterial population or intestinal morphology. Among digestive enzymes, only sucrase increased linearly as propolis was increased. Thus, supplementation with propolis increased the growth performance of broiler chickens positively and the effect was dose dependent. This may have been partly because of an improvement in sucrase activity and other factors related to the nutritional content of propolis. Future study to evaluate specific bioactive compounds of propolis is therefore warranted.

Composition and distribution of α-dicarbonyl compounds in propolis from different plant origins and extraction processing

α-Dicarbonyl compounds (α-DCs), mainly produced during thermal treatment and storage of sugary foods, are routinely measured to evaluate food quality. Propolis is a functional food that has gained wide usage; thus, its quality control is an emerging concern. There are no reports on distribution of α-DCs in propolis. In this study, 10 main α-DCs standards of o-phenylenediamine (OPD) derivatives were prepared and confirmed by high resolution mass spectrometry. Based on these standards, an ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) was established and validated to determine the α-DCs in different propolis samples. Nine α-DCs were detected, ranging from 0.006 to 44.936 mg/kg. Methyl glyoxal (MGO), 2,3-butanedione and glucosone are rich in content, with the highest content of MGO. The level of 3-deoxypentosulose (3-DG) increased sharply with long-term storage of propolis extracts. The comparison revealed 20-fold lower levels of MGO when supercritical CO2 extraction and ethanol extraction were used, highlighting the importance of extraction techniques used in processing raw propolis. The investigation of commercially available propolis products found that α-DCs were in the range of 0.013–16.181 mg/kg. The results indicated that α-DCs can be the potential index to control propolis quality.

Potential hepatoprotective effects of flavonoids contained in propolis from South Sulawesi against chemotherapy agents.

The use of doxorubicin and epirubicin as chemotherapy agent causes side effects such as liver damage due to oxidative stress by reactive oxygen species (ROS) that cause increased of ALT and AST level as liver parameter. One source of natural antioxidants as ROS neutralizer comes from flavonoid that contain in propolis. Most researchers claim that flavonoid can be used to protect the liver. The aim of this study was to test the hepatoprotective effect of flavonoid in propolis from South Sulawesi against doxorubicin and epirubicin. The experiment included male Sprague dawley rats divided into nine groups. The rats received the microcapsule propolis or the quercetin orally for 15 days. The hepatotoxicity was promoted by injection epirubicin and doxorubicin (i.v.) with a cumulative dose of 9 mg/kg. In this study, total polyphenol and flavonoid tests of propolis have been carried out, there were 1.1% polyphenols and 2.7% flavonoids, the antioxidant activity tests showed IC50 value of 9849 ppm and LCMS/MS tests supported the presence of phenolic compounds in propolis from South Sulawesi. Liver parameter was measured and the results showed that the propolis 200 mg/kg group produced the lowest ALT and had potential protective effect against doxorubicin and epirubicin-induced hepatotoxicity.

Caffeic Acid Phenethyl Ester (CAPE), Active Phenolic Compound of Propolis Attenuates Endothelin, Prostaglandin F2α and U46619 Elicited Contractions of Isolated Human Umbilical Artery

Background: Propolis is a product of honeybees that contains a variety of different compounds, including caffeic acid phenethyl ester (CAPE). Propolis and its bioactive compounds are widely used in folk medicine and as a dietary supplement. Previously it has been shown that CAPE has antioxidant, anti-inflammatory, antimicrobial, antiviral, immunomodulatory, and anticancer activity. Objective: This in vitro study was designed to investigate the vasoactive effects of CAPE on quiescent and precontracted human umbilical arteries. Methods: Umbilical artery strips were suspended in aerated organ baths containing a buffer solution. The strips were randomly allocated to study groups (n=8). Via a transducer and computer, changes in isometric tension were recorded. The effects of cumulative CAPE (10-8-10-4M) on basal tone of the artery, and in different groups of strips, the vasodilatory effect of cumulative CAPE on the constriction elicited by endothelin (ET-1), prostaglandin F2α (PGF2α) and U46619, and the effect of incubation with NO synthase inhibitor L-NAME, were recorded. Conclusion: CAPE elicits concentration-dependent relaxation on precontracted human umbilical artery strips depending on the constrictor agent. NO plays significant role in CAPE’s vasorelaxant effect.

High-throughput subzero-temperature assisted homogenous liquid-liquid extraction for the fast sample preparation of multiple phenolic compounds in propolis

In the present study, a high-throughput homogenous liquid-liquid extraction method was developed for fast sample preparation of multiple phenolic compounds in propolis. This method was proposed based on cooling samples array in subzero temperature to induce phase separation of ACN-H2O extractant. Due to the high-throughput ability, optimization of extraction parameters was rapidly achieved by using a 5 × 4 × 3 samples array. In addition, multiple arrays were investigated for evaluating the analytical performance of the high-throughput method, which indicated that limits of detection and quantification were ranged from 0.04 to 0.35 µg/mL and 0.12 to 1.05 µg/mL, respectively. Recoveries and precisions in inter-day high-throughput studies were in the range of 90.55–105.50% and 2.58–4.30%, respectively. Comparing with the conventional liquid extraction method, this ecofriendly high-throughput method presented remarkable advantages in reducing sample and chemical consumption, as well as saving labor and time cost. The proposed method might provide a valuable strategy for the design of high-throughput extraction procedures.

Effects of propolis and its bioactive components on breast cancer cell pathways and the molecular mechanisms involved.

Breast cancer is a female malignancy that is a significant cause of mortality worldwide. Currently, investigations on natural ingredients as new candidates for chemopreventive agents and breast cancer chemotherapies are increasing. Propolis is a natural resinous material produced by honeybees that exhibit anticancer potential. Several studies have mentioned the major bioactive compounds of propolis, but their mechanism of action is not clearly understood. The purpose of this review is to collect and summarize the evidence related to the effectiveness of propolis and its bioactive contents as candidates for breast cancer therapy and analyze the molecular mechanisms involved in their therapeutic pathways. We reviewed 94 articles from journals and databases, extracted the results, and produced summaries and conclusions. Propolis and its bioactive ingredients show cytotoxic, anti-proliferative, pro-autophagic, anti-metastatic, and antioxidant activities, as well as synergistic effects with chemotherapy or radiotherapy in breast cancer. Its therapeutic activity involves various target molecules, including NF-κβ, Fas receptors, p53, TLR4, ANXA7, and voltage-gated Na+ channel (VGSC). The bioactive components of propolis and the target molecules involved need to be explored further to develop new breast cancer therapies and overcome the problem of chemoradiation resistance.

Green Propolis Compounds (Baccarin and p-Coumaric Acid) Show Beneficial Effects in Mice for Melanoma Induced by B16f10.

: Background: Cutaneous melanoma is the most aggressive form of skin cancer, with the worst prognosis, and it affects a younger population than most cancers. The high metastatic index, in more advanced stages, and the high aggressiveness decrease the effectiveness of currently used therapies, such as surgical removal, radiotherapy, cryotherapy, and chemotherapy, used alone or in combination. Based on these disadvantages, research focused on alternative medicine offers great potential for therapeutic innovation. Medicinal plants represent a remarkable source of compounds for the treatment of various diseases. Methods: In this study, we investigated the tumoral behavior of melanoma under treatment with the compounds baccharin and p-coumaric acid, extracted from green propolis, in mice inoculated with B16F10 cells for 26 days. Results: A significant modulation in the number of inflammatory cells recruited to the tumor region and blood in the groups treated with the compounds was observed. In addition, a significant reduction in the amount of blood vessels and mitosis in the neoplastic area was noticed. Conclusions: Through our research, we confirmed that baccharin and coumaric acid, isolated substances from Brazilian green propolis, have a promising anticarcinogenic potential to be explored for the development of new antitumor agents, adhering to the trend of drugs with greater tolerance and biological effectiveness.

Propolis microencapsulation by double emulsion solvent evaporation approach: Comparison of different polymeric matrices and extract to polymer ratio

Propolis, a heterogeneous matrix produced by honeybees, is an antioxidant amongst other valuable biological properties. Nevertheless, the practical application of propolis, especially for the food industry, is still limited due to its relative high hydrophilicity and strong/unpleasant taste and aroma. Accordingly, microencapsulation arises a potential alternative approach to protect propolis compounds while allowing to mask its unpleasant sensory properties.The purpose of this study was to microencapsulate propolis extracts in lipophilic polymer-carriers using alternative propolis extract to polymer ratios – 1/4, 1/2 and 3/4 – by double emulsion solvent evaporation approach. The product yield was higher than the previously reported in the literature (80.3±3.7% versus 68%).The encapsulation efficiencies (considering the encapsulated antioxidants and phenolic compounds) were independent from the propolis extract to polymer ratio, for the studied lipophilic polymer-carriers. The results of this work provide promising approaches for the manufacture of propolis extracts-loaded microparticles for further incorporation in functional matrices.

Nonclinical Toxicological Studies of Brazilian Red Propolis and Its Primary Botanical Source Dalbergia ecastaphyllum.

Propolis is one of the most widely used products in traditional medicine. One of the most prominent types of Brazilian propolis is the red one, whose primary botanical source is Dalbergia ecastaphyllum (L.) Taub. Despite the potential of Brazilian red propolis for developing new products with pharmacological activity, few studies guarantee safety in its use. The objective of this study was the evaluation of the possible toxic effects of Brazilian red propolis and D. ecastaphyllum, as well as the cytotoxicity assessment of the main compounds of red propolis on tumoral cell lines. Hydroalcoholic extracts of the Brazilian red propolis (BRPE) and D. ecastaphyllum stems (DSE) and leaves (DLE) were prepared and chromatographed for isolation of the major compounds. RP-HPLC-DAD was used to quantify the major compounds in the obtained extracts. The XTT assay was used to evaluate the cytotoxic activity of the extracts in the human fibroblast cell line (GM07492A). The results revealed IC50 values of 102.7, 143.4, and 253.1 μg/mL for BRPE, DSE, and DLE, respectively. The extracts were also evaluated for their genotoxic potential in the micronucleus assay in Chinese hamster lung fibroblasts cells (V79), showing the absence of genotoxicity. The BRPE was investigated for its potential in vivo toxicity in the zebrafish model. Concentrations of 0.8-6.3 mg/L were safe for the animals, with a LC50 of 9.37 mg/L. Of the 11 compounds isolated from BRPE, medicarpin showed a selective cytotoxic effect against the HeLa cell line. These are the initial steps to determine the toxicological potential of Brazilian red propolis.

A Narrative and Meta‑Analytic Study of in vivo Efficiency of the Bioactive Compounds of Propolis in Tooth Decay

A Narrative and Meta‑Analytic Study of in vivo Efficiency of the Bioactive Compounds of Propolis in Tooth Decay

Co-crystallized sucrose with propolis extract as a food ingredient: Powder characterization and antioxidant stability

Propolis possesses health beneficial properties due to its antioxidant compounds; however, its solubility in alcohol and its strong and unpleasant taste limit the use of propolis extract in foods. This study explores the encapsulation of a propolis ethanolic extract by co-crystallization in a sucrose matrix to eliminate the alcohol and to obtain a propolis powder with suitable technological properties and high antioxidant activity to be used as a food ingredient. The effect of the propolis extract on colour, moisture content, solubility, particle size distribution, flow properties and spectroscopic characteristics (FTIR) of the co-crystallized powders was determined. Polyphenols and flavonoids content and antioxidant capacity (ABTS and DPPH) during storage of the powders were also analysed. The propolis co-crystallized powders showed moisture contents below 2% and good flow properties, except at the higher content of the extract. The FTIR results showed that the presence of propolis did not alter the crystalline sucrose structure. Entrapment yields higher than 84% (flavonoids) and 78% (polyphenols) were obtained. During storage of the powders high stability of these compounds was observed at light, darkness and refrigeration conditions. Thus, co-crystallization technique constitutes a low cost alternative for the protection of bioactive compounds of propolis.

Phenolic Compounds of Propolis Alleviate Lipid Metabolism Disorder.

Lipid metabolism disorder is one of the significant risk factors for a multitude of human diseases and has become a serious threat to human health. The present study aimed to evaluate the effects of phenolics from poplar-type propolis on regulating lipid metabolism by using cell models of steatosis induced by palmitic acid (PA). Our study shows that phenolic esters have higher lipid-lowering activities than phenolic acids, especially for three caffeic acid esters, including caffeic acid phenethyl ester (CAPE), caffeic acid cinnamyl ester (CACE), and caffeic acid benzyl ester (CABE). Most notably, CACE presents prominent properties to prevent intracellular lipid accumulation and to amend extracellular adipokine secretion abnormalities. In addition, our results firstly reveal that CACE can alleviate lipid metabolism disorder through mediating protein kinase RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6) signaling pathway-associated protein expression, suppressing endoplasmic reticulum (ER) stress, and activating peroxisome proliferator-activated receptors (PPARs) by distinct upregulation of PPARα and downregulation of PPARγ.

IDENTIFYING PROPOLIS COMPOUNDS POTENTIAL TO BE COVID-19 THERAPIES BY TARGETING SARS-COV-2 MAIN PROTEASE

Objective: The study aims to perform molecular docking to examine the interaction between propolis compound and SARS-CoV-2 main protease.
 Methods: The protein target of this research was the crystal structure of SARS-CoV-2 main protease in complex with an inhibitor N3 (PDB ID: 6LU7). The ligand of this research was the bioactive compounds from Propolis of Tetragonula aff. biroi. 
 Results: The results showed that propolis compound which has the potential to inhibit SARS-CoV-2 protease activity was Sulabiroins A (binding affinity-8.1 kcal/mol), following by (2S)-5,7-dihydroxy-4'-methoxy-8-prenylflavanone acid and broussoflavonol F (binding affinity-7.9 kcal/mol) with binding similarity more than 50% compared to N3-main protease interaction.
 Conclusion: Molecular docking showed propolis compounds of Tetragonula aff. biroi potential to inhibit SARS-CoV-2 main protease activity. The highest binding affinity presented by Sulabiroins A, following by (2S)-5,7-dihydroxy-4'-methoxy-8-prenylflavanone acid and broussoflavonol F, with values of-8.1 kcal/mol,-7.9 kcal/mol, and-7.9 kcal/mol, respectively, with binding similarity more than 50% compared to N3 and SARS-CoV-2 main protease interaction.

Bending Strength of Wood Treated with Propolis Extract and Silicon Compounds.

The modification of wood and its treatment with various preservatives may affect its mechanical properties, hence the knowledge of the character changes in wood caused by impregnation is of great importance. Therefore, the aim of the research was to determine the effect of impregnation, with the propolis-silane preparation (EEP-MPTMOS/TEOS) consisting of the propolis extract (EEP) and silicon compounds: 3-(trimethoxysilyl)propyl methacrylate (MPTMOS) and tetraethoxysilane (TEOS), on the bending strength of treated wood. Moreover, in the study wood treated with components of the propolis-silane formulation was used, namely 70% ethanol, the propolis extract, and silanes (MPTMOS/TEOS). In order to determine whether the impregnation of wood affects its long-term bending, creep tests were performed depending on the humidity. The impregnation of wood with the propolis extract and the propolis-silane preparation (EEP-MPTMOS/TEOS) contributed to the increase in modulus of rapture and work to maximum load values compared to the untreated wood. In dry wood condition, the wood treated with EEP and EEP-MPTMOS/TEOS was characterized by lower modulus of elasticity values than the control samples. In turn, in wet wood condition, wood treated with the propolis-silane preparation showed an increase in the MOE value. Moreover, the impregnation of wood had an influence on the wood creep process under bending loads. The treated wood was characterized by higher relative creep compliance than the untreated wood. The exception was the wood impregnated with EEP-MPTMOS/TEOS, which showed comparable relative creep compliance to the control samples. The presented results indicate that wood treated with a bio-friendly preparation based on propolis and silicon compounds can be used in various application and also in variable humidity conditions.

New Insights Into Potential Benefits of Bioactive Compounds of Bee Products on COVID-19: A Review and Assessment of Recent Research.

The recent emergence of COVID‐19 represents one of the biggest challenges facing the world today. Despite the recent attempts to understand the epidemiological pattern and pathogenesis of the disease, detailed data about the physiology and pathology of the disease is still out of reach. Moreover, the lack of a widespread vaccine prompts an urgent call for developing a proper intervention strategy against the virus. Importantly, identification of novel molecules that target replication of the virus represents one of the promising strategies for the control this pandemic crisis. Among others, honey bee products contain numerous bioactive compounds such as propolis and several phenolic compounds that possess a wide range of therapeutic properties for combating various pathological disorders and infectious agents. The intention of the present review is to highlight the stages of SARS-CoV-2 lifecycle, the molecular mechanisms explaining the health benefits of honey bee products on COVID‐19 physiology and pathology and the possible limitations. Further future research is suggested to explore more about bee natural bioactive compounds as potential candidates against SARS-CoV-2.

Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal.

To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I—saline; group II—propolis 100 µg/mL; group III—propolis 300 µg/mL; group IV—propolis nanoparticle 100 µg/mL; group V—propolis nanoparticle 300µg/mL; group VI—6% sodium hypochlorite; group VII—2% chlorhexidine. Dentin shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal–Wallis and Mann–Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and β-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm−1 band and an increase in the 870 cm−1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.

Evaluating the potency of Sulawesi propolis compounds as ACE-2 inhibitors through molecular docking for COVID-19 drug discovery preliminary study

Coronavirus disease (COVID-19) is a global pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Up to date, there has been no specific cure to treat the disease. Indonesia is one of the countries that is still fighting to control virus transmission. Yet, at the same time, Indonesia has a rich biodiversity of natural medicinal products that potentially become an alternative cure. Thus, this study examined the potency of a natural medicinal product, Sulawesi propolis compounds produced by Tetragonula sapiens, inhibiting angiotensin-converting activity enzyme-2 (ACE-2), a receptor of SARS-CoV-2 in the human body. In this study, molecular docking was done to analyze the docking scores as the representation of binding affinity and the interaction profiles of propolis compounds toward ACE-2. The results illustrated that by considering the docking score and the presence of interaction with targeted sites, five compounds, namely glyasperin A, broussoflavonol F, sulabiroins A, (2S)-5,7-dihydroxy-4′-methoxy-8-prenylflavanone and isorhamnetin are potential to inhibit the binding of ACE-2 and SARS-CoV-2, with the docking score of −10.8, −9.9, −9.5, −9.3 and −9.2 kcal/mol respectively. The docking scores are considered to be more favorable compared to MLN-4760 as a potent inhibitor.

Selection and evaluation of quality control markers in propolis based on its hyperlipidemia therapy via regulating PXR/CYP3A4 expression

BackgroundPropolis and its preparations are components of TCM and functional food sources for antihyperlipidemia therapy. However, due to the metabolic properties of propolis, its individual components remain ambiguous, especially those that are therapeutically active. PurposeThe study presented here identified the primary target (PXR/CYP3A4) of propolis activity against hyperlipidemia and evaluated individual compounds of propolis to select a quality control marker based on this activity. MethodsMice fed a high-fat diet were used to study the efficacy of propolis, followed by identification of substantially influenced glycolipid regulatory target(s) by propolis. Since propolis had the strongest effect on PXR expression, we took advantage of its downstream target CYP3A4, the drug metabolism activity of such enzyme is affected by alterations in PXR expression. Thus, we used the production of 1’-hydroxy-midazolam as an indicator. Compounds found by UHPLC-TOF-MS were added to a HepG2 cell solution (transfected by PXR mRNA and the CYP3A4 plasmid to simulate drug metabolism in the body) in the form of a monomer, followed by the addition of midazolam. Changes in the amount of “indicator” were used to investigate each compound's qualitative (promote or suppress) and quantitative activity. Compounds with obvious effects were quantified in propolis extract, as confirmed via Western Blot analysis regarding their PXR regulatory activity, and subjected to pharmacokinetic analysis to biter understand their metabolism in the body. Finally, components passing these screens could be regarded as quality control markers capable of indicating the efficacy of antihyperlipidemic activity via PXR/CYP3A4 regulation. ResultsThe use of propolis was effective in lowering TG and TC levels in mice, as well as in repairing their injured livers; its activity was comparable to the chemical and TCM positive controls. Propolis mainly suppressed PXR expression compared with other regulatory targets that were tested. Most of the individual compounds from propolis (13 out of 15) showed obvious regulatory activity of PXR/CYP3A4; however, content quantification and pharmacokinetic analyses narrowed the selection to 2 compounds, kaempferol and chrysin, as the main active components responsible for the antihyperlipidemic effect of propolis. In other words, this study suggested that propolis mainly acts on the PXR/CYP3A4 pathway to regulate glycolipid metabolism, and the 2 compounds mentioned above can be used as quality control markers (QM) to evaluate the efficacy of this activity. ConclusionPropolis's antihyperlipidemic effect relies on its regulation of PXR/CYP3A4 expression. Kaempferol and chrysin can be regarded as QMs. In addition, the metabolite-based method for evaluating regulatory activity is much faster, more effective, and more reliable than the conventional screening method, paving the way for its future applications.