Extraction, purification, structural character and biological properties of propolis flavonoids: A review

Borago Officinalis L.: A Review Oon Extraction, Phytochemical, and Pharmacological Activities

Borago officinalis L., an annual herb belonging to the Boraginaceae family, is used in the traditional medical practices of various countries and for multiple treatments, including respiratory disorders, colds, influenza, diarrhea, cramps, inflammation, palpitation, hypertension menopause, and post-menopausal symptoms. Its pharmacological properties and biological activities - among them antioxidant, antimicrobial, anticancer, anti-inflammatory, insecticidal, antigenotoxic, and anti-obesity activity - were demonstrated in vitro and in vivo and are related to its rich content of bioactive compounds (mainly phenolic acids, flavonoids, anthocyanins, alkaloids, and terpenes) extracted from various parts of B. officinalis including leaves, flowers, seeds, and roots. This review summarizes all updated information on applied extraction processes, phytochemistry, pharmacology, and toxicity of B. officinalis.

Enrichment and Evaluation of Antitumor Properties of Total Flavonoids from Juglans mandshurica Maxim

Flavonoids are important secondary metabolites found in Juglans mandshurica Maxim., which is a precious reservoir of bioactive substances in China. To explore the antitumor actions of flavonoids (JMFs) from the waste branches of J. mandshurica, the following optimized purification parameters of JMFs by macroporous resins were first obtained. The loading concentration, flow rate, and loading volume of raw flavonoid extracts were 1.4 mg/mL, 2.4 BV/h, and 5 BV, respectively, and for desorption, 60% ethanol (4 BV) was selected to elute JMFs-loaded AB-8 resin at a flow rate of 2.4 BV/h. This adsorption behavior can be explained by the pseudo-second-order kinetic model and Langmuir isotherm model. Subsequently, JMFs were identified using Fourier transform infrared combined with high-performance liquid chromatography and tandem mass spectrometry, and a total of 156 flavonoids were identified. Furthermore, the inhibitory potential of JMFs on the proliferation, migration, and invasion of HepG2 cells was demonstrated. The results also show that exposure to JMFs induced apoptotic cell death, which might be associated with extrinsic and intrinsic pathways. Additionally, flow cytometry detection found that JMFs exposure triggered S phase arrest and the generation of reactive oxygen species in HepG2 cells. These findings suggest that the JMFs purified in this study represent great potential for the treatment of liver cancer.

Effect of Mexican Propolis on Wound Healing in a Murine Model of Diabetes Mellitus

Diabetes mellitus (DM) affects the wound healing process, resulting in impaired healing or aberrant scarring. DM increases reactive oxygen species (ROS) production, fibroblast senescence and angiogenesis abnormalities, causing exacerbated inflammation accompanied by low levels of TGF-β and an increase in Matrix metalloproteinases (MMPs). Propolis has been proposed as a healing alternative for diabetic patients because it has antimicrobial, anti-inflammatory, antioxidant and proliferative effects and important properties in the healing process. An ethanolic extract of Chihuahua propolis (ChEEP) was obtained and fractionated, and the fractions were subjected to High-Performance Liquid Chromatography with diode-array (HPLC-DAD), High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses and 46 compounds were detected. Deep wounds were made in a murine DM model induced by streptozotocin, and the speed of closure and the wound tensile strength were evaluated by the tensiometric method, which showed that ChEEP had similar activity to Recoveron, improving the speed of healing and increasing the wound tensile strength needed to open the wound again. A histological analysis of the wounds was performed using H&E staining, and when Matrix metalloproteinase 9 (MMP9) and α-actin were quantified by immunohistochemistry, ChEEP was shown to be associated with improved histological healing, as indicated by the reduced MMP9 and α-actin expression. In conclusion, topical ChEEP application enhances wound healing in diabetic mice.

Exploring the Functional Properties of Propolis, Geopropolis, and Cerumen, with a Special Emphasis on Their Antimicrobial Effects

Bee propolis has been touted as a natural antimicrobial agent with the potential to replace antibiotics. Numerous reports and reviews have highlighted the functionalities and applications of the natural compound. Despite much clamor for the downstream application of propolis, there remain many grounds to cover, especially in the upstream production, and factors affecting the quality of the propolis. Moreover, geopropolis and cerumen, akin to propolis, hold promise for diverse human applications, yet their benefits and intricate manufacturing processes remain subjects of intensive research. Specialized cement bees are pivotal in gathering and transporting plant resins from suitable sources to their nests. Contrary to common belief, these resins are directly applied within the hive, smoothed out by cement bees, and blended with beeswax and trace components to create raw propolis. Beekeepers subsequently harvest and perform the extraction of the raw propolis to form the final propolis extract that is sold on the market. As a result of the production process, intrinsic and extrinsic factors, such as botanical origins, bee species, and the extraction process, have a direct impact on the quality of the final propolis extract. Towards the end of this paper, a section is dedicated to highlighting the antimicrobial potency of propolis extract.

Egyptian propolis extract for functionalization of cellulose nanofiber/poly(vinyl alcohol) porous hydrogel along with characterization and biological applications

Bee propolis is one of the most common natural extracts and has gained significant interest in biomedicine due to its high content of phenolic acids and flavonoids, which are responsible for the antioxidant activity of natural products. The present study report that the propolis extract (PE) was produced by ethanol in the surrounding environment. The obtained PE was added at different concentrations to cellulose nanofiber (CNF)/poly(vinyl alcohol) (PVA), and subjected to freezing thawing and freeze drying methods to develop porous bioactive matrices. Scanning electron microscope (SEM) observations displayed that the prepared samples had an interconnected porous structure with pore sizes in the range of 10-100 μm. The high performance liquid chromatography (HPLC) results of PE showed around 18 polyphenol compounds, with the highest amounts of hesperetin (183.7 µg/mL), chlorogenic acid (96.9 µg/mL) and caffeic acid (90.2 µg/mL). The antibacterial activity results indicated that both PE and PE-functionalized hydrogels exhibited a potential antimicrobial effects against Escherichia coli, Salmonella typhimurium, Streptococcus mutans, and Candida albicans. The in vitro test cell culture experiments indicated that the cells on the PE-functionalized hydrogels had the greatest viability, adhesion, and spreading of cells. Altogether, these data highlight the interesting effect of propolis bio-functionalization to enhance the biological features of CNF/PVA hydrogel as a functional matrix for biomedical applications.

Evaluation of the Antioxidant Activities and Phenolic Profile of Shennongjia Apis cerana Honey through a Comparison with Apis mellifera Honey in China

This study evaluates the phenolic profile as well as the antioxidant properties of Shennongjia Apis cerana honey through a comparison with Apis mellifera honey in China. The total phenolic content (TPC) ranges from 263 ± 2 to 681 ± 36 mg gallic acid/kg. The total flavonoids content (TFC) ranges from 35.9 ± 0.4 to 102.2 ± 0.8 mg epicatechin/kg. The correlations between TPC or TFC and the antioxidant results (FRAP, DPPH, and ABTS) were found to be statistically significant (p < 0.01). Furthermore, the phenolic compounds are quantified and qualified by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS), and a total of 83 phenolic compounds were tentatively identified in this study. A metabolomics analysis based on the 83 polyphenols was carried out and subjected to principal component analysis and orthogonal partial least squares-discriminant analysis. The results showed that it was possible to distinguish Apis cerana honey from Apis mellifera honey based on the phenolic profile.

In vivo and in vitro studies of a propolis-enriched silk fibroin-gelatin composite nanofiber wound dressing

In this study, electrospun nanofibers (NFs) used in trauma dressings were prepared using silk fibroin (SF) and gelatin (GT) as materials and highly volatile formic acid as the solvent, with three different concentrations of propolis extracts (EP), which were loaded through a simple process. The resulting samples were characterized by surface morphology, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), contact angle meter, water absorption, degradation rate, and mechanical property tests. The incorporation of propolis improved its antibacterial properties against Escherichia coli, and Staphylococcus aureus, compared to those of the silk gelatin nanofiber material (SF/GT) alone. In vitro biocompatibility assays showed that SF/GT-1%EP had good cytocompatibility and hemocompatibility. In addition, it can also significantly promote the migration of L929 cells. SF/GT-1%EP was applied to a mouse model of full thickness skin defects, and it was found to significantly promote wound healing. These results indicate that the SF/GT-EP nanofiber material has good biocompatibility, migrating-promoting capability, antibacterial properties, and healing-promoting ability, providing a new idea for the treatment of full thickness skin defects.

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.

Obtaining and Characterizing Andean Multi-Floral Propolis Nanoencapsulates in Polymeric Matrices

Propolis is a substance with significant anti-inflammatory, anticancer, and antiviral activity, which could be used more efficiently at the nano level as an additive in the food industry. The aim was to obtain and characterize nanoencapsulated multi-floral propolis from the agro-ecological region of Apurimac, Peru. For nanoencapsulation, 5% ethanolic extracts propolis with 0.3% gum arabic and 30% maltodextrin were prepared. Then, the mixtures were dried by nano spraying at 120 °C using the smallest nebulizer. The flavonoid content was between 1.81 and 6.66 mg quercetin/g, the phenolic compounds were between 1.76 and 6.13 mg GAE/g, and a high antioxidant capacity was observed. The results of moisture, water activity, bulk density, color, hygroscopicity, solubility, yield, and encapsulation efficiency were typical of the nano spray drying process. The total organic carbon content was around 24%, heterogeneous spherical particles were observed at nanometer level (between 11.1 and 562.6 nm), with different behaviors in colloidal solution, the thermal gravimetric properties were similar in all the encapsulates, the FTIR and EDS analysis confirmed the encapsulation and the X-ray diffraction showed amorphous characteristics in the obtained material; stability and phenolic compound release studies indicated high values of 8.25–12.50 mg GAE/g between 8 and 12 h, the principal component analysis confirmed that the flora, altitude, and climate of the propolis location influenced the content of bioactive compounds, antioxidant capacity, and other properties studied. The nanoencapsulate from the district of Huancaray was the one with the best results, allowing its future use as a natural ingredient in functional foods. Nevertheless, technological, sensory, and economic studies should still be carried out.

Pectin-type polysaccharide from galangal: An efficient emulsifier to construct the emulsion-based delivery system for galangal flavonoids

Galangal is rich in flavonoids and polysaccharides but underutilized. In this study, galangal flavonoids and polysaccharides (GP-HN and GP-UN) were obtained by segmented extraction, used for chemical composition determination/structural characterization, and constructed for the emulsion delivery system. The results showed that galangin accounted for 71.45 % of total flavonoids. GP-HN and GP-UN were prepared by enzymatic-assisted high-temperature and ultrasonic extraction, which were low-molecular-weight pectin-type polysaccharides mainly constructed by galacturonic acid, galactose, and arabinose. GP-UN was the best emulsifier due to interfacial activities, emulsifying properties, interfacial resistance to bile salts displacement abilities, and anti-lipid digestion abilities of GPs. GP-UN emulsion could stably deliver flavonoids. This study presented a method for orderly reorganizing flavonoids and polysaccharides, guiding for utilization of whole bioactive components in galangal.

Antifungal Activity of Mexican Propolis on Clinical Isolates of Candida Species

Infections caused by micro-organisms of the genus Candida are becoming a growing health problem worldwide. These fungi are opportunistic commensals that can produce infections—clinically known as candidiasis—in immunocompromised individuals. The indiscriminate use of different anti-fungal treatments has triggered the resistance of Candida species to currently used therapies. In this sense, propolis has been shown to have potent antimicrobial properties and thus can be used as an approach for the inhibition of Candida species. Therefore, this work aims to evaluate the anti-Candida effects of a propolis extract obtained from the north of Mexico on clinical isolates of Candida species. Candida species were specifically identified from oral lesions, and both the qualitative and quantitative anti-Candida effects of the Mexican propolis were evaluated, as well as its inhibitory effect on C. albicans isolate’s germ tube growth and chemical composition. Three Candida species were identified, and our results indicated that the inhibition halos of the propolis ranged from 7.6 to 21.43 mm, while that of the MFC and FC₅₀ ranged from 0.312 to 1.25 and 0.014 to 0.244 mg/mL, respectively. Moreover, the propolis was found to inhibit germ tube formation (IC₅₀ ranging from 0.030 to 1.291 mg/mL). Chemical composition analysis indicated the presence of flavonoids, including pinocembrin, baicalein, pinobanksin chalcone, rhamnetin, and biochanin A, in the Mexican propolis extract. In summary, our work shows that Mexican propolis presents significant anti-Candida effects related to its chemical composition, and also inhibits germ tube growth. Other Candida species virulence factors should be investigated in future research in order to determine the mechanisms associated with antifungal effects against them.

From propolis to nanopropolis: An exemplary journey and a paradigm shift of a resinous substance produced by bees

Propolis, a natural resinous mixture produced by honey bees is poised with diverse biological activities. Owing to the presence of flavonoids, phenolic acids, terpenes, and sesquiterpenes, propolis has garnered versatile applications in pharmaceutical industry. The biopharmaceutical issues associated with propolis often beset its use as being too hydrophobic in nature; it is not absorbed in the body well. To combat the problem, various nanotechnological approaches for the development of novel drug delivery systems are generally applied to improve its bioavailability. This paradigm shift and transition of conventional propolis to nanopropolis are evident from the literature wherein a multitude of studies are available on nanopropolis with improved bioavailability profile. These approaches include preparation of gold nanoparticles, silver nanoparticles, magnetic nanoparticles, liposomes, liquid crystalline formulations, solid lipid nanoparticles, mesoporous silica nanoparticles, etc. Nanopropolis has further been explored to assess the potential benefits of propolis for the development of futuristic useful products such as sunscreens, creams, mouthwashes, toothpastes, and nutritional supplements with improved solubility, bioavailability, and penetration profiles. However, more high-quality clinical studies assessing the effects of propolis either alone or in combination with synthetic drugs as well as natural products are warranted and its safety needs to be firmly established.