The Phenolic Compounds, Metabolites, and Antioxidant Activity of Propolis Extracted by Ultrasound‐Assisted Method

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.

The effects of ultrasound on probiotic functionality: an updated review

The effects of ultrasound (US) on probiotics, as health-promoting microbes, have attracted the attention of researchers in fermentation and healthy food production. This paper aims to review recent advances in the application of the US for enhancing probiotic cells' activity, elaborate on the mechanisms involved, explain how probiotic-related industries can benefit from this emerging food processing technology, and discuss the perspective of this innovative approach. Data showed that US could enhance fermentation, which is increasingly used to enrich agri-food products with probiotics. Among the probiotics, recent studies focused on Lactiplantibacillus plantarum, Lactobacillus brevis, Lactococcus lactis, Lactobacillus casei, Leuconostoc mesenteroides, Bifidobacteria. These bacteria proliferated in the log phase when treated with US at relatively low-intensities. Also, this non-thermal technology increased extracellular enzymes, mainly β-galactosidase, and effectively extracted antioxidants and bioactive compounds such as phenolics, flavonoids, and anthocyanins. Accordingly, better functional and physicochemical properties of prebiotic-based foods (e.g., fermented dairy products) can be expected after ultrasonication at appropriate conditions. Besides, the US improved fermentation efficiency by reducing the production time, making probiotics more viable with lower lactose content, more oligosaccharide, and reduced unpleasant taste. Also, US can enhance the rheological characteristics of probiotic-based food by altering the acidity. Optimizing US settings is suggested to preserve probiotics viability to achieve high-quality food production and contribute to food nutrition improvement and sustainable food manufacturing.

Comparative Methods to Evaluate the Antioxidant Capacity of Propolis: An Attempt to Explain the Differences

Propolis is a natural product produced by bees that contains a complex mixture of compounds, including phenolic compounds and flavonoids. These compounds contribute to its biological activities, such as antioxidant capacity. This study analysed the pollen profile, total phenolic content (TPC), antioxidant properties, and phenolic compound profile of four propolis samples from Portugal. The total phenolic compounds in the samples were determined by six different techniques: four different Folin-Ciocalteu (F-C) methods, spectrophotometry (SPECT), and voltammetry (SWV). Of the six methods, SPECT allowed the highest quantification, while SWV achieved the lowest. The mean TPC values for these methods were 422 ± 98 and 47 ± 11 mg GAE/g sample, respectively. Antioxidant capacity was determined by four different methods: DPPH, FRAP, original ferrocyanide (OFec), and modified ferrocyanide (MFec). The MFec method gave the highest antioxidant capacity for all samples, followed by the DPPH method. The study also investigated the correlation between TPC and antioxidant capacity with the presence of hydroxybenzoic acid (HBA), hydroxycinnamic acid (HCA), and flavonoids (FLAV) in propolis samples. The results showed that the concentrations of specific compounds in propolis samples can significantly impact their antioxidant capacity and TPC quantification. Analysis of the profile of phenolic compounds by the UHPLC-DAD-ESI-MS technique identified chrysin, caffeic acid isoprenyl ester, pinocembrin, galangin, pinobanksin-3-O-acetate, and caffeic acid phenyl ester as the major compounds in the four propolis samples. In conclusion, this study shows the importance of the choice of method for determining TPC and antioxidant activity in samples and the contribution of HBA and HCA content to their quantification.

Deciphering the mechanisms of Yinlan Tiaozhi capsule in treating hyperlipidemia by combining network pharmacology, molecular docking and experimental verification

Yinlan Tiaozhi capsule (YLTZC) has been widely used to treat hyperlipidemia (HLP). However, its material basis and underlying pharmacological effects remain unclean. The current study aimed to explore the mechanisms involved in the treatment of YLTZC on HLP based on network pharmacology, molecular docking, and experimental verification. Firstly, UPLC-Q-TOF-MS/MS was used to comprehensively analyze and identify the chemical constituents in YLTZC. A total of 66 compounds, mainly including flavonoids, saponins, coumarins, lactones, organic acids, and limonin were characterized and classified. Simultaneously, the mass fragmentation pattern of different types of representative compounds was further explored. By network pharmacology analysis, naringenin and ferulic acid may be the core constituents. The 52 potential targets of YLTZC, including ALB, IL-6, TNF, and VEGFA, were considered potential therapeutic targets. Molecular docking results showed that the core active constituents of YLTZC (naringenin and ferulic acid) have a strong affinity with the core targets of HLP. Lastly, animal experiments confirmed that naringenin and ferulic acid significantly upregulated the mRNA expression of ALB and downregulated the mRNA expression of IL-6, TNF, and VEGFA. In sum, the constituents of YLTZC, such as naringenin and ferulic acid, might treat HLP by regulating the mechanism of angiogenesis and inhibiting inflammatory responses. Furthermore, our data fills the gap in the material basis of YLTZC.

Ultrasound-assisted extraction of polyphenols from Chinese propolis

Introduction

Propolis is a beneficial bioactive food with rich polyphenols content. Nowadays, an increasing interest is attracted to the extraction of polyphenols from raw propolis. This study utilized the novel ultrasound-assisted approach for polyphenol extraction from Chinese propolis, aiming to improve its extraction yield and reveal the relevant mechanisms via extraction kinetic study as well as the compositional and structural analysis.

Methods

The optimum ultrasound-assisted extraction conditions were optimized according to the total phenolic content and total flavonoids content. Compositional and structural analysis were conducted using high performance liquid chromatography-quadrupole-time of flight tandem mass spectrometry, high-performance liquid chromatography, Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM).

Results and discussion

The optimum ultrasound-assisted extraction conditions were as follows: ratio of liquid to solid, 60:1; ultrasound power, 135 W; ultrasound duration, 20 min. Under the optimum conditions, the antioxidant activities of the extract were increased by 95.55% and 64.46% by 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability assay and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging ability assay, respectively, compared to those obtained by traditional maceration. The second-order kinetics model was employed to study the extraction process; it was found that ultrasound significantly accelerated the extraction of propolis and increased the maximum extraction volume of phenolic compounds. The qualitative and quantitative analysis of polyphenol compositions showed that ultrasound did not change the polyphenol types in the extract but it significantly improved the contents of various flavonoids and phenolic acids such as galangin, chrysin, pinocembrin, pinobanksin and isoferulic acid. Likewise, the FT-IR analysis indicated that the types of functional groups were similar in the two extracts. The SEM analysis revealed that the ultrasound-assisted extraction enhanced the contact areas between propolis and ethanol by breaking down the propolis particles and eroding the propolis surface.

Impact of particle size on the nutrition release and antioxidant activity of rape, buckwheat and rose bee pollens

In this study, the effects of particle size on the microstructure, nutrient components and antioxidant activities of bee pollen were evaluated. Moreover, the in vitro simulated digestion model was used to explore whether there was a size effect on the release behavior of phenolic compounds from the bee pollen matrix. Results showed that the greater the damage degree of the bee pollen wall, the smaller the bee pollen particle became. The decrease in the bee pollen particle size promoted the release and extractability of sugar, protein, phenolics and flavonoids, and improved their antioxidant activities. In addition, during simulated digestion, the dissolution of total phenolics and flavonoids, as well as the antioxidant activities of bee pollen, increased with the decrease in the particle size. Results showed that minimizing the particle size of bee pollen was not always beneficial for bioaccessible phenolic compounds because their content and bioavailability decreased when the particle size became smaller than 200 μm.

Brazilian green propolis extracts modulate cholesterol homeostasis in a preclinical guinea pig model: an in vitro and in vivo study

Green propolis produced by Apis melífera bees, having Baccharis dracunculifolia D.C. (Asteraceae) as the primary botanical source, has been used in traditional medicine to treat numerous disorders. However, studies evaluating propolis' potential in treating cardiovascular diseases via its effects on cholesterol metabolism are lacking. Therefore, this study investigated the effects of green propolis extracts on lipid metabolism in hypercholesterolemic guinea pigs. Chemical characterization of ethanolic extracts of green propolis samples was undertaken using HPLC. The in vitro characterization included an evaluation of the antioxidant capacity of the hydroalcoholic extract of green propolis (DPPH and FRAP assays) and its ability to act as an inhibitor of the HMG-CoA reductase enzyme. In vivo, we investigated the effect of the hydroalcoholic extract of green propolis on lipid metabolism in hypercholesterolemic guinea pigs. Results obtained validated previous reports of significant antioxidant activity. HPLC analysis confirmed that coumaric acid, artepillin C, and baccharin were the most common and abundant compounds in green propolis samples among the studied compounds. Furthermore, the compounds in these extracts acted as effective HMG-CoA reductase inhibitors in vitro. In vivo assays demonstrated that a hypercholesterolemic diet significantly reduced serum levels of the HDL cholesterol fraction. Simvastatin and propolis hydroalcoholic extracts promoted a significant increase in HDL cholesterol, suggesting that these extracts can improve the serum lipid profile of hypercholesterolemic guinea pigs. Results obtained in this study provide a perspective on the possible hypocholesterolemic effect of green propolis, suggesting that it can improve the serum lipid profile in hypercholesterolemic guinea pigs.

Phenolic Constituents, Antioxidant and Antimicrobial Activity and Clustering Analysis of Propolis Samples Based on PCA from Different Regions of Anatolia

This study aimed to evaluate the biochemical composition and biological activity of propolis samples from different regions of Türkiye to characterize and classify 24 Anatolian propolis samples according to their geographical origin. Chemometric techniques, namely, principal component analysis (PCA) and a hierarchical clustering algorithm (HCA), were applied for the first time to all data, including antioxidant capacity, individual phenolic constituents, and the antimicrobial activity of propolis to reveal the possible clustering of Anatolian propolis samples according to their geographical origin. As a result, the total phenolic content (TPC) of the propolis samples varied from 16.73 to 125.83 mg gallic acid equivalent per gram (GAE/g) sample, while the number of total flavonoids varied from 57.98 to 327.38 mg quercetin equivalent per gram (QE/g) sample. The identified constituents of propolis were phenolic/aromatic acids (chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, and trans-cinnamic acid), phenolic aldehyde (vanillin), and flavonoids (pinocembrin, kaempferol, pinobanksin, and apigenin). This study has shown that the application of the PCA chemometric method to the biochemical composition and biological activity of propolis allows for the successful clustering of Anatolian propolis samples from different regions of Türkiye, except for samples from the Black Sea region.

The Antioxidant and Anti-Inflammatory Effects of Flavonoids from Propolis via Nrf2 and NF-κB Pathways

Accumulating evidence shows that oxidative stress and inflammation contribute to the development of cardiovascular disease. It has been suggested that propolis possesses antioxidant and anti-inflammatory activities. In this study, the antioxidant and anti-inflammatory effects of the main flavonoids of propolis (chrysin, pinocembrin, galangin, and pinobanksin) and propolis extract were researched. The results showed that the cellular ROS (Reactive oxygen species) levels, antioxidant enzymes, Nrf2 (Nuclear factor erythroid 2-related factor 2) nuclear translocation, and the expression of NQO1 (NAD(P)H:quinone oxidoreductase 1) and HO-1 (heme oxygenase 1) were regulated by different concentrations of individual flavonoids and propolis extract, which showed good antioxidant and pro-oxidant effects. For example, ROS levels were decreased; SOD and CAT activities were increased; and the expression of HO-1 protein was increased by chrysin. The results demonstrated that NO (Nitric Oxide), NOS (Nitric Oxide Synthase), and the activation of the NF-κB signaling pathway were inhibited in a dose-dependent manner by different concentrations of individual flavonoids and propolis extract. Moreover, the results revealed that the phytochemicals presented antioxidant effects at lower concentrations but pro-oxidant effects and stronger anti-inflammatory effects at higher concentrations. To maintain the balance of antioxidant and anti-inflammatory effects, it is possible that phytochemicals activate the Nrf2 pathway and inhibited the NF-κB (Nuclear factor kappa B) pathway.

Pharmacokinetics, Prostate Distribution and Metabolic Characteristics of Four Representative Flavones after Oral Administration of the Aerial Part of Glycyrrhiza uralensis in Rats

(1) Background: The aerial part of G. uralensis had pharmacological effects against chronic non-bacterial prostatitis (CNP), and flavonoids are the main efficacy components. The purpose of this study was to obtain the pharmacokinetics, prostate distribution and metabolic characteristics of some flavonoids in rats. (2) Methods: The prototype flavones and the metabolites of four representative flavonoids, namely puerarin, luteolin, kaempferol and pinocembrin in plasma, prostate, urine and feces of rats were analyzed by UPLC-Q-Exactive Orbitrap-MS. In addition, the pharmacokinetic parameters in plasma and distribution of prostate of four components were analyzed by HPLC-MS/MS. (3) Results: In total, 22, 17, 22 and 11 prototype flavones were detected in the prostate, plasma, urine and feces, respectively. The metabolites of puerarin in the prostate are hydrolysis and glucose-conjugated products, the metabolites of kaempferol and luteolin in the prostate are methylation and glucuronidation, and the metabolites of pinocembrin in the prostate are naringenin, oxidation, sulfation, methylation and glucuronidation products. The t1/2 of puerarin, luteolin, kaempferol and pinocembrin was 6.43 ± 0.20, 31.08 ± 1.17, 18.98 ± 1.46 and 13.18 ± 0.72 h, respectively. The concentrations of the four flavonoids in prostate were ranked as kaempferol > pinocembrin > luteolin > puerarin. (4) Conclusions: Methylation and glucuronidation metabolites were the main metabolites detected in the prostate. A sensitive and validated HPLC−MS/MS method for simultaneous determination of puerarin, luteolin, kaempferol and pinocembrin in rat plasma and prostate was described, and it was successfully applied to the pharmacokinetic and prostate distribution studies.

Extraction, Antioxidant Capacity, 5-Lipoxygenase Inhibition, and Phytochemical Composition of Propolis from Eastern Canada

Soxhlet (SE), microwave-assisted (MAE) and ultrasound-assisted (UAE) extraction were compared using ten extraction solvents for their efficiency to extract phenolic and flavonoid antioxidants from Eastern Canada propolis. Extracts were compared for total phenolic (TPC) and total flavonoid (TFC) content, and radical scavenging activities. Anti-inflammatory activity through inhibition of 5-lipoxygenase (5-LO) products biosynthesis in HEK293 cells was also evaluated. The results showed that SE extracts using polar solvents had the highest TPC and TFC. Extracts obtained with ethanol, methanol and acetone were effective free radical scavengers, and showed 5-LO inhibition similar to zileuton. UAE was an effective extraction method since the extracts obtained were comparable to those using SE and the MAE while being done at room temperature. With UAE, extracts of less polar solvents showed similar free radical scavenging and 5-LO inhibition to extracts of much more polar solvents such as methanol or ethanol. Reversed-phase liquid chromatography tandem mass spectrometry confirmed the presence of 21 natural compounds in the propolis extracts based on the comparison of intact mass, chromatographic retention time and fragmentation patterns derived from commercial analytical standards. The current study is the first of its kind to concurrently investigate solvent polarity as well as extraction techniques of propolis.