Comparison of Ethanolic and Aqueous-Polyethylenglycolic Propolis Extracts: Chemical Composition and Antioxidant Properties

Effects of clove (Syzygium aromaticum) extract on antibacterial activity, phytochemical properties, and storage quality of flavored milk beverages

The antibacterial efficacy of clove extracts (Syzygium aromaticum) prepared using 80% ethanol and water against pathogenic bacteria was evaluated, along with the development of a novel antimicrobial milk beverage incorporating these extracts. Seven flavored milk beverage (FMB) treatments were prepared: a control and 6 with clove extracts at 0.5%, 0.7%, and 1% for each solvent. The effects on physicochemical, phytochemical, antioxidant, microbiological, color, and sensory properties were assessed over 15 d of storage at 4 ± 1°C. The ethanolic clove extract exhibited significantly higher antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157, Salmonella typhi, and Klebsiella pneumoniae, with inhibition zone diameters of 20 mm, 21 mm, 20 mm, 19 mm, and 20 mm, respectively, compared with the aqueous extract. On d 0, the sample of 1% ethanolic clove extract (FMB3) showed the highest proximate analysis values, including TS (22.41%), protein (4.61%), fat (4.58%), ash (0.97%), and gross energy (108.65 Kcal). It also showed the highest pH (6.7), flavor score (19.20), texture score (9), and overall acceptability score (39.50), and the lowest carbohydrate content (12.27%), lightness value (69.60), and yellowness value (97.47). Over the 15-d storage period, the total phenolic content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) increased, with the FMB3 sample exhibiting the highest TPC (58.70 mg/100 g), TFC (46.15 mg/100 g), and TAC (487.10 mg/100 g). All beverages remained free from yeasts and molds, and FMB3 exhibited the lowest bacterial count (5.13 log cfu/mL). The results indicate that ethanolic clove extract effectively inhibits spoilage and pathogenic organisms and enhances the sensory and functional properties of FMB. This finding offers a promising approach for improving the quality and safety of dairy products.

Research Progress on the Chemical Constituents and Pharmacological Effects of Houttuynia cordata Thunb and a Predictive Analysis of Quality Markers

Houttuynia cordata (H. cordata) is widely used in respiratory disease control as an important heat-clearing and detoxifying traditional Chinese medicine. It effectively clears away heat and toxins, eliminates carbuncles, and drains pus, and it is diuretic and detoxicating. The aim of this study is to review the botany, chemical composition, pharmacological effects, and quality control of H. cordata to establish a better-quality evaluation system. Google Scholar, Baidu Scholar, PubMed, ScienceDirect, Web of Science, and multiple databases, including China National Knowledge Infrastructure (CNKI) and Wanfang Data, were searched. A structural diagram of the compound was drawn using ChemDraw software. H. cordata contains volatile oils, flavonoids, and alkaloids. It has antibacterial, anti-inflammatory, antiviral, antioxidant, antitumor, and immunity-enhancing pharmacological effects. By analyzing the literature, it was predicted that Houttuynia sodium, methyl nonyl ketone, quercetin, and quercitrin could be used as the quality markers (Q-marker) of H. cordata. This provides a basis for further research into the applications of H. cordata.

Effects of aqueous and ethanolic extracts of Chinese propolis on dental pulp stem cell viability, migration and cytokine expression

Background

Propolis is a natural substance produced by honeybees that has various biological properties including, anti-inflammatory, antioxidant and antimicrobial properties. Although previous studies have evaluated the antimicrobial effects of propolis in dentistry, its effects on dental pulp stem cell (DPSC) viability, migration, and differentiation are yet not well understood. The objective of this study was to investigate the effects of Chinese propolis on viability/proliferation, migration, differentiation and cytokine expression in DPSCs.

Methods

Commercially available DPSCs (Lonza) were treated with aqueous extract of propolis (AEP) or ethanolic extract of propolis (EEP), and viability/proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays and quantification of nuclear staining. DPSC differentiation into mineralizing cells was evaluated with Alizarin red staining and cell migration was assessed using Boyden Chamber Transwell inserts. Cytokine expression was measured by RT-qPCR. AEP and EEP at 0.03 and 0.1 mg/mL did not affect DPSC viability/proliferation for up to 7-days treatment.

Results

Higher doses (0.33-33 mg/mL) induced a dose dependent decrease in DPSC viability/proliferation with a more prominent effect with EEP at 7 days. Neither AEP nor EEP induced DPSC differentiation into mineralizing cells, but both AEP and EEP (0.03-0.1 mg/ml) induced a dose dependent increase in DPSC migration. In addition, EEP prevents the upregulation of IL1b and IL6 but not IL8 and CCL2 in response to lipopolysaccharide stimulation. AEP has less potent anti-inflammatory effects and prevents only IL1b upregulation.

Conclusion

This study provides new information about the biologic properties of ethanolic and aqueous extracts of propolis and shows that propolis, at doses that do not affect cell viability, induces DPSC migration and has anti-inflammatory properties. These data highlight the potential use of propolis as an alternative intra-canal medicament for regenerative endodontic procedures.

Advances in the phytochemical screening and biological potential of propolis

Propolis is a natural resinous product collected from different parts of plants by bees and mixed with their salivary secretions. The occurrence of more than 180 different chemotypes has flavonoids, phenolic acids, esters, and phenolic aldehydes, as well as balsamic resins, beeswax, pollen, and essential and aromatic oils, among others. Its biological potential documented throughout the world justifies the need, from time to time, to organize reviews on the subject, with the intention of gathering and informing about the update on propolis. In this review (CRD42020212971), phytochemical advances, in vitro, in vivo, and clinical biological assays of pharmacological interest are showcased. The focus of this work is to present propolis clinical safety assays, antitumor, analgesic, antioxidant, anti-inflammatory, and antimicrobial activities. This literature review highlights propolis' promising biological activity, as it also suggests that studies associating propolis with nanotechnology should be further explored for enhanced bioprocessing applications.

Polyurethane-Nanolignin Composite Foam Coated with Propolis as a Platform for Wound Dressing: Synthesis and Characterization

This piece of research explores porous nanocomposite polyurethane (PU) foam synthesis, containing nanolignin (NL), coated with natural antimicrobial propolis for wound dressing. PU foam was synthesized using polyethylene glycol, glycerol, NL, and 1, 6-diisocyanato-hexane (NCO/OH ratio: 1.2) and water as blowing agent. The resultant foam was immersed in ethanolic extract of propolis (EEP). PU, NL-PU, and PU-NL/EEP foams were characterized from mechanical, morphological, and chemical perspectives. NL Incorporation into PU increased mechanical strength, while EEP coating showed lower strength than PU-NL/EEP. Morphological investigations confirmed an open-celled structure with a pore diameter of 150-200 μm, a density of nearly 0.2 g/cm3,, and porosity greater than 85%, which led to significantly high water absorption (267% for PU-NL/EEP). The hydrophilic nature of foams, measured by the contact angle, proved to be increased by NL addition and EEP coating. PU and PU-NL did not show important antibacterial features, while EEP coating resulted in a significant antibacterial efficiency. All foams revealed high biocompatibility toward L929 fibroblasts, with the highest cell viability and cell attachment for PU-NL/EEP. In vivo wound healing using Wistar rats' full-thickness skin wound model confirmed that PU-NL/EEP exhibited an essentially higher wound healing efficacy compared with other foams. Hence, PU-NL/EEP foam could be a promising wound dressing candidate.

Nonaqueous Polyethylene Glycol as a Safer Alternative to Ethanolic Propolis Extracts with Comparable Antioxidant and Antimicrobial Activity

We compared the chemical composition, antioxidant and antimicrobial activity of two propolis extracts: one obtained with nonaqueous polyethylene glycol, PEG 400 (PgEP), and the other obtained with ethanol (EEP). We analyzed the total phenolic content (TPC) and the concentrations of ten markers of propolis antioxidant activity with HPLC-UV: caffeic acid, p-coumaric acid, trans-ferulic acid, trans-cinnamic acid, kaempferol, apigenin, pinocembrin, chrysin, CAPE, and galangin. Antioxidant activity was tested using DPPH and FRAP assay, and antimicrobial activity was assessed through minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentration (MBEC) determination. Maceration gave the yield of propolis of 25.2 ± 0.08% in EEP, and 21.5 ± 0.24% in PgEP. All ten markers of antioxidant activity were found in both extracts, with all marker concentrations, except kaempferol, higher in EEP. There was no significant difference between the TPC and antioxidant activity of the PgEP and the EEP extract; TPC of PgEP was 16.78 ± 0.23 mg/mL, while EEP had TPC of 15.92 ± 0.78 mg/mL. Both extracts had antimicrobial activity against most investigated pathogens and Staphylococcus aureus, Acinetobacter baumannii, and Escherichia coli biofilms. EEP was more effective against all tested susceptible pathogens, except E. coli, possibly due to higher content of kaempferol in PgEP relative to other polyphenols. Nonaqueous PEG 400 could be used for propolis extraction. It gives extracts with comparable concentrations of antioxidants and has a good antioxidant and antimicrobial activity. It is a safe excipient, convenient for pediatric and veterinary formulations.