Effect of light, oxygen and temperature on the stability of artepillin C and p-coumaric acid from Brazilian green propolis

Constituents From Brazilian Propolis Against Edwardsiella ictaluri and Flavobacterium covae, Two Bacteria Affecting Channel Catfish (Ictalurus punctatus)

Edwardsiella ictaluri and Flavobacterium covae are two bacteria species that cause diseases in farm-raised channel catfish (Ictalurus punctatus) that cause heavy economic damage to the aquaculture industry, particularly to the channel catfish farming. In search for environmentally benign antibacterial compounds active against E. ictaluri and F. covae, we investigated the constituents isolated from Brazilian red, brown and green propolis. We have also synthetically modified active constituents to see if lipophilicity plays a role in enhancing antibacterial activities. Vestitol, neovestitol and methylvestitol were found to be the active constituents with minimum inhibitory concentration (MIC) relative to drug control florfenicol (RDCF) values (MIC-RDCF) of 7.6, 7.6 and 7.9 mg/L, respectively, against F. covae. The activity against E. ictaluri was not significant.

Effect of heat-treated flaxseed lignan macromolecules on the interfacial properties and physicochemical stability of α-linolenic acid-enriched O/W emulsions

Flaxseed lignan macromolecules (FLMs) are important polyphenols present in flaxseeds with interfacial adsorption behavior. However, FLMs are easily degraded during thermal treatment in emulsions, which further influences their interfacial properties and application. In this work, the interfacial properties of FLMs between oil and water were evaluated using compression isotherms and interfacial tension to investigate the regulation mechanism of FLMs and their heat-treated products on the stability of O/W emulsions. Furthermore, the improvement mechanism of FLM heat-treated products on the physicochemical stability of flaxseed oil emulsions was clarified. Studies showed that thermal degradation occurred on terminal phenolic acids in FLMs when treated under 100 and 150 °C (FLM-100 and FLM-150) without any decrease in antioxidant activity. FLM-100 and FLM-150 improved the physicochemical stability of sunflower lecithin (S90)-stabilized flaxseed oil emulsions and reduced the concentration of hydroperoxides and TBARS by 26.7% and 80% (p < 0.05), respectively, during storage. This was due to the high interfacial anchoring of FLM-100 and FLM-150, which further strengthened the interface of oil droplets and improved the interfacial antioxidant effect of FLMs. This implies that FLM-100 and FLM-150 could act as new efficient antioxidants for application in food emulsions.

Larvicidal Activity of Constituents from the Main Brazilian Propolis Types: Green, Red, and Brown against Aedes aegypti

In search of environmentally benign and mammalian-friendly mosquito-mitigating compounds, we conducted an investigation into the constituents isolated from Brazilian red, brown, and green propolis. Additionally, we synthetically modified active constituents to explore the role of lipophilicity in enhancing their larvicidal activity. Honeybees collect plant resins from their habitats, mix them with saliva, and utilize them to seal their beehives. The constituents present in propolis exhibit a unique composition specific to the geographical location and the fauna of the region. As part of the plant's natural defense mechanism, propolis compounds demonstrate antibacterial, insecticidal, and phytotoxic properties. Given that several insecticides target the enzyme acetylcholinesterase, we conducted in silico studies to examine the interactions between propolis compounds and acetylcholinesterase through molecular docking. In this study, we present the mosquito larvicidal activities of propolis constituents.

Chemical Characterization and Biological Activities Evaluation of Myrtus communis L. Essential Oil Extraction By-Product towards Circular Economy and Sustainability

Essential oil (EO) extraction is a widespread practice generating huge amounts of solid plant by-products a potential source of bioactive compounds, on the one hand, and a detrimental risk for the environment that needs to be carefully considered on the other hand. The present study aims to valorize Myrtus communis L. leaf by-products obtained following EO extraction using a steam distillation unit through the recovery of phenolic compounds and the evaluation of their biological activities. The total phenols, flavonoids, and proanthocyanidins contents of the ethanolic extract by-product were higher than the control (leaves without extraction of EO). Their amounts increased from 69.30 to 88.06 mg GAE/g for total phenols, from 36.31 to 70.97 mg QE for flavonoids and from 19.74 to 21.49 mg CE/g of extract for proanthocyanidins. The identification of phenolic compounds by high-performance liquid-chromatography equipped with a reversed-phase (RP-HPLC) system revealed that the by-product sample includes more gallic acid, catechin, syringic acid and luteolin 7-O-glucoside but less p-coumaric acid and kaempferol than the control. Moreover, the mid-infrared spectroscopy (MIR) showed the presence of benzene ring characteristic of phenolic compounds at 756 cm-1, esters of aromatic acids and stretching vibrations of polyphenols at 1141-1234 cm-1, C=C stretching present in phenolic acids such as coumaric acid and catechin at 1604 cm-1. The assessment of antioxidant activity revealed that the ABTS+• radical scavenging activity was significantly increased, whereas the DPPH• radical inhibition activity and the ferric reduction antioxidant power were significantly decreased. The results indicated, as well, that Myrtus communis L. leaf by-products maintained a considerable antibacterial activity depending on the tested bacterial strain. Additionally, the anti-α-amylase activity was higher for the Myrtus communis L. leaf by-product extract. Therefore, Myrtus communis L. leaf by-products of EO extraction offer phenolic compounds with significant biological activities, contributing to the sustainable development and the promotion of circular economy by the recovery of valuable inputs from plant by-products.

Microencapsulation of bioactive compound extracts using maltodextrin and gum arabic by spray and freeze-drying techniques

Microencapsulation techniques establish a protective barrier around a sensitive compound, reducing vulnerability to external influences and offering controlled release. This work evaluates microencapsulation of Brazilian seed known as pink pepper (Schinus terebinthifolius) extract incorporated with green propolis extract, (main propolis font from the South America native plant Baccharis dracunculifolia DC) to enhancement antioxidant activity through synergic interaction, comparing to the extracts individually. Four treatments were produced using maltodextrin and combined with gum arabic as encapsulating agent, employing two different microencapsulation technique applied (spray drying and freeze drying) to assess their impact on physicochemical properties. The incorporation of gum arabic into matrix yielded higher encapsulation efficiency values, exhibiting significant differences for both encapsulation techniques. Combining the two encapsulation agents afforded greater protection of the bioactive compounds, resulting in an increase of approximately 31 % in the inhibition of the DPPH● radical. In controlled release analysis, maltodextrin exhibits the best protective effect on total phenolic compounds during intestinal release, whereas combining maltodextrin and gum arabic enhanced protection during gastric phase. Microcapsules may contribute to the protection of important bioactive compound, possessing a wide range of applications such as flavors encapsulation in food industry, lipids, antioxidants and pharmaceutical industry for controlled drug release.

Characterization of Brazilian green propolis as a photosensitizer for LED light-induced antimicrobial photodynamic therapy (aPDT) against methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-intermediate Staphylococcus aureus (VISA)

Staphylococcus aureus is the primary cause of skin and soft tissue infections. Its significant adaptability and the development of resistance are the main factors linked to its spread and the challenges in its treatment. Antimicrobial photodynamic therapy emerges as a promising alternative. This work aimed to characterize the antimicrobial photodynamic activity of Brazilian green propolis, along with the key bioactive compounds associated with this activity. Initially, a scanning spectrometry was conducted to assess the wavelengths with the potential to activate green propolis. Subsequently, reference strains of methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300) and vancomycin-intermediate Staphylococcus aureus (VISA ATCC 700699) were exposed to varying concentrations of green propolis: 1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg /mL and 100 µg/mL and were stimulated by blue, green or red LED light. Finally, high-performance liquid chromatography coupled with a diode array detector and tandem mass spectrometry techniques, along with classic molecular networking analysis, was performed to identify potential bioactive molecules with photodynamic activity. Brazilian green propolis exhibits a pronounced absorption peak and heightened photo-responsiveness when exposed to blue light within the range of 400 nm and 450 nm. This characteristic reveals noteworthy significant photodynamic activity against MRSA and VISA at concentrations from 5 µg/mL. Furthermore, the propolis comprises compounds like curcumin and other flavonoids sourced from flavone, which possess the potential for photodynamic activity and other antimicrobial functions. Consequently, Brazilian green propolis holds promise as an excellent bactericidal agent, displaying a synergistic antibacterial property enhanced by light-induced photodynamic effects.

Development and Characterization of High-Absorption Microencapsulated Organic Propolis EPP-AF® Extract (i-CAPs)

The demand for organic and functional food continues to increase yearly. Among the available functional foods, propolis is a bee product that has various beneficial properties, including antimicrobial, antioxidant, and anti-inflammatory activities. However, it generally is only available in ethanol solution, which has poor bioavailability, as it is relatively insoluble in water. The use of such ethanol extracts is often objectionable because of the alcohol content and because they have a strong and striking taste. Development of alternatives that can efficiently and safely increase solubility in water, and that meet organic production specifications, has been a challenge. To address these concerns, microcapsules were developed using spray-dryer technology from an emulsion based on EPP-AF® propolis and gum arabic (i-CAPS). These propolis-loaded microcapsules were characterized using FT-IR, SEM, TGA, HPLC, and spectrophotometric techniques, along with determination of antimicrobial, antioxidant, antitumor, anti-inflammatory, and antihypercholesterolemic activities, as well as permeability in in vitro models. The production system resulted in microcapsules with a spherical shape and an encapsulation efficiency of 93.7 ± 0.7%. They had IC50s of 2.654 ± 0.062 and 7.342 ± 0.058 µg/mL by FRAP and DPPH antioxidant methods, respectively. The EPP-AF® i-CAPS also had superior antimicrobial activity against Gram-positive bacteria. Antitumor activity was calculated based on the concentration that inhibited 50% of growth of AGS, Caco-2, and MCF-7 cell strains, giving results of 154.0 ± 1.0, 117 ± 1.0, and 271.0 ± 25 µg/mL, respectively. The microcapsule presentation reduced the permeation of cholesterol by 53.7%, demonstrating antihypercholesterolemic activity, and it improved the permeability of p-coumaric acid and artepillin C. The IC50 for NO production in RAW 264.7 cells was 59.0 ± 0.1 µg/mL. These findings demonstrate the potential of this new propolis product as a food and pharmaceutical ingredient, though additional studies are recommended to validate the safety of proposed dosages.

Propolis as a Cariostatic Agent in Lozenges and Impact of Storage Conditions on the Stability of Propolis

Propolis is known as a source of compounds with strong antibacterial activity. Due to the antibacterial effect against streptococci of the oral cavity, it seems to be a useful agent in decreasing the accumulation of dental plaque. It is rich in polyphenols which are responsible for a beneficial impact on the oral microbiota and antibacterial effect. The aim of the study was to evaluate the antibacterial effect of Polish propolis against cariogenic bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined on cariogenic streptococci related to the occurrence of dental caries. Lozenges based on xylitol, glycerin, gelatin, water, and ethanol extract of propolis (EEP) were prepared. The effect of prepared lozenges on cariogenic bacteria was assessed. Propolis was compared to chlorhexidine which is used in dentistry as the gold standard. In addition, the prepared propolis formulation was stored under stress conditions to assess the influence of physical conditions (i.e., temperature, relative humidity, and UV radiation). In the experiment, thermal analyses were also performed to evaluate the compatibility of propolis with the substrate used to create the base of lozenges. The observed antibacterial effect of propolis and prepared lozenges with EEP may suggest directing subsequent research on prophylactic and therapeutic properties decreasing the accumulation of dental plaque. Therefore, it is worth highlighting that propolis may play an important role in the management of dental health and bring advantages in preventing periodontal diseases and caries as well as dental plaque. The colorimetric analyses carried out in the CIE L*a*b* system, microscopic examinations, and TGA/DTG/c-DTA measurements indicate the unfavorable effect of the tested storage conditions on the lozenges with propolis. This fact is particularly evident for lozenges stored under stress conditions, i.e., 40 °C/75% RH/14 days, and lozenges exposed to UVA radiation for 60 min. In addition, the obtained thermograms of the tested samples indicate the thermal compatibility of the ingredients used to create the formulation of lozenges.

Development and Characterization of New Green Propolis Extract Formulations as Promising Candidates to Substitute for Green Propolis Hydroalcoholic Extract

The technologies used to produce the different dosage forms of propolis can selectively affect the original propolis compounds and their biological activities. The most common type of propolis extract is hydroethanolic. However, there is considerable demand for ethanol-free propolis presentations, including stable powder forms. Three propolis extract formulations were developed and investigated for chemical composition and antioxidant and antimicrobial activity: polar propolis fraction (PPF), soluble propolis dry extract (PSDE), and microencapsulated propolis extract (MPE). The different technologies used to produce the extracts affected their physical appearance, chemical profile, and biological activity. PPF was found to contain mainly caffeic and p-Coumaric acid, while PSDE and MPE showed a chemical fingerprint closer to the original green propolis hydroalcoholic extract used. MPE, a fine powder (40% propolis in gum Arabic), was readily dispersible in water, and had less intense flavor, taste, and color than PSDE. PSDE, a fine powder (80% propolis) in maltodextrin as a carrier, was perfectly water-soluble and could be used in liquid formulations; it is transparent and has a strong bitter taste. PPF, a purified solid with large amounts of caffeic and p-Coumaric acids, had the highest antioxidant and antimicrobial activity, and therefore merits further study. PSDE and MPE had antioxidant and antimicrobial properties and could be used in products tailored to specific needs.

Potential Use of Brazilian Green Propolis Extracts as New Photosensitizers for Antimicrobial Photodynamic Therapy against Cariogenic Microorganisms

The synergic effect of Streptococcus mutans and Candida albicans increases dental caries severity. Antimicrobial photodynamic therapy (aPDT) is a non-invasive treatment for antimicrobial aspects. However, the current photosensitizers (PS) have many downsides for dental applications. This study aimed to evaluate the efficiency of two different Brazilian green propolis (BGP-AF and BGP-AG) as PS for aPDT against these microorganisms. A single-species biofilm was irradiated with crude extracts and their fractions and controls. Such extracts showed the best results and were evaluated in dual-species biofilms. Photodegradation, reactive oxygen species (ROS), cytotoxicity, and color stability assays were also investigated. Reductions higher than 3 log₁₀ CFU/mL (p < 0.0001) occurred for crude BGP in single- and dual-species biofilms. Singlet oxygen was produced in BGP (p < 0.0001). BGP-mediated aPDT delayed S. mutans and C. albicans regrowth after 24 h of treatment (p < 0.0001). Both BGP did not change the color of dental materials (p > 0.05). BGP-AF-mediated aPDT showed 72.41% of oral keratinocyte viability (p < 0.0001). BGP extracts may be used in aPDT against S. mutans and C. albicans. Specifically, BGP-AF may represent a promising PS for dental applications.

Esterification of p-Coumaric Acid Improves the Control over Melanoma Cell Growth

Previous studies reported that p-coumaric acid modulates melanoma growth. Because the esterification of p-coumaric acid (p-CA) enhanced its activity as an antimelanogenic agent, we aimed to determine the antitumor potential of two derivatives, the ethyl and butyl esters, against the murine B16-F10 and the human SK-MEL-25 melanoma cells. Cell viability was determined in vitro by the lactate dehydrogenase release and violet crystal absorption assays. The cell proliferation rate and cell cycle behavior were determined by the colony formation assay and flow cytometry analysis. Although p-CA, at the concentration of 1 mM, failed to exert a significant antitumor activity, the ethyl and butyl ester derivatives caused substantial tumor cell death at doses < 1 mM. Despite a reduction in their direct cytotoxicity at minor doses, both products controlled the melanoma growth by arresting the cell cycle at the G0/G1 (B16-F10) or S/G2 (SK-MEL-25). Furthermore, the in vivo experiments showed that the butyl ester derivative suppressed the lung B16-F10 burden, compared to the p-CA-treated mice. Thus, the esterification of p-coumaric acid improved the control over the proliferation of murine and human melanoma cells and can be considered an approach for designing novel anticancer agents.

Phytochemical Constituents and Derivatives of Cannabis sativa; Bridging the Gap in Melanoma Treatment

Melanoma is deadly, physically impairing, and has ongoing treatment deficiencies. Current treatment regimens include surgery, targeted kinase inhibitors, immunotherapy, and combined approaches. Each of these treatments face pitfalls, with diminutive five-year survival in patients with advanced metastatic invasion of lymph and secondary organ tissues. Polyphenolic compounds, including cannabinoids, terpenoids, and flavonoids; both natural and synthetic, have emerging evidence of nutraceutical, cosmetic and pharmacological potential, including specific anti-cancer, anti-inflammatory, and palliative utility. Cannabis sativa is a wellspring of medicinal compounds whose direct and adjunctive application may offer considerable relief for melanoma suffers worldwide. This review aims to address the diverse applications of C. sativa's biocompounds in the scope of melanoma and suggest it as a strong candidate for ongoing pharmacological evaluation.

Brazilian Brown Propolis: an Overview About Its Chemical Composition, Botanical Sources, Quality Control, and Pharmacological Properties

Brazil is one of the largest propolis producers in the world. Propolis is produced by bees from plant exudates and tissues, leading to many variations in the types of propolis. Generally, Brazilian propolis types are green, brown, and red. Despite not being the main research focus as the green and red propolis, brown propolis is the second most produced propolis type in Brazil and has tremendous economic and medicinal importance. Propolis has drawn attention with the rise in the search for healthier lifestyles, functional foods, biocosmetics, and natural products as therapeutic sources. This review covers the main chemical constituents identified in different types of Brazilian brown propolis, and their botanical sources, chemistry, and biological activities. The economic aspect of brown propolis is also presented. There are many gaps to be filled for brown propolis regarding the development of analytical methods, and quality control to allow its standardization, limiting its applicability in the food and pharmaceutical industries. Future perspectives regarding brown propolis research were discussed, especially biological activities, to support the medicinal uses of different types of brown propolis.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00374-x.

Chitosan–Hydroxycinnamic Acids Conjugates: Emerging Biomaterials with Rising Applications in Biomedicine

Over the past thirty years, research has shown the huge potential of chitosan in biomedical applications such as drug delivery, tissue engineering and regeneration, cancer therapy, and antimicrobial treatments, among others. One of the major advantages of this interesting polysaccharide is its modifiability, which facilitates its use in tailor-made applications. In this way, the molecular structure of chitosan has been conjugated with multiple molecules to modify its mechanical, biological, or chemical properties. Here, we review the conjugation of chitosan with some bioactive molecules: hydroxycinnamic acids (HCAs); since these derivatives have been probed to enhance some of the biological effects of chitosan and to fine-tune its characteristics for its application in the biomedical field. First, the main characteristics of chitosan and HCAs are presented; then, the currently employed conjugation strategies between chitosan and HCAs are described; and, finally, the studied biomedical applications of these derivatives are discussed to present their limitations and advantages, which could lead to proximal therapeutic uses.

Chemical characterization of Brazilian propolis using automated direct thermal desorption-gas chromatography-mass spectrometry

BACKGROUND

Propolis, produced by honey bees, is used around the world, displaying several corroborated biological activities. Brazil is one of the leading producers of propolis, with a great diversity of types, each with a characteristically chemical fingerprint influenced by the flora of the local region. The secondary metabolite's composition of propolis strongly impacts its biological properties, and its chemical characterization is of great importance for its quality control. Several chromatographic techniques have been applied to characterize propolis, highlighting the extraction of its volatiles and its analysis through gas chromatography. Fourteen Brazilian propolis samples collected in four states, including brown, green and red propolis types, were chemically characterized using the automated direct thermal desorption-gas chromatography-mass spectrometry (DTD-GC-MS).

RESULTS

Red propolis type was characterized by acyclic saturated hydrocarbons, fatty alcohols, terpenes, and phenylpropanoids as nonacosane, α-copaene, β-amyrin acetate, anethole, and 7-O-methylvestitol. Brown propolis presented hydrocarbons, monoterpenes, and sesquiterpenes, as α-pinene and α-bisabolol. Brazilian green propolis presented polycyclic aromatic hydrocarbons and sesquiterpenes, including 1-methyl-octahydroanthracene, 2,5-dimethyl-γ-oxo-benzenebutanoic acid, nerolidol, and spathulenol. Principal component analysis (PCA) was performed, allowing for clustering brown and red propolis types, indicating a divergence with the chemical composition of the green propolis samples. The hierarchical cluster analysis (HCA) allowed the chemical fingerprint of each propolis type to be differentiated.

CONCLUSION

Red propolis was characterized by sesquiterpenes, pterocarpans, and isoflavans; brown propolis was characterized by hydrocarbons, aldehydes, and monoterpenes, while green propolis samples were characterized by the presence of polycyclic aromatic hydrocarbons, sesquiterpenes, and naphthalene derivatives. © 2022 Society of Chemical Industry.

Disinfectant activities of extracts and metabolites from Baccharis dracunculifolia DC

The concern regarding the harm caused by biocides to human health has been increasing over the years, making the natural products an alternative to less toxic and more efficient biocides. Therefore, this paper reports the investigation of the disinfectant potential of extracts and isolated compounds from Baccharis dracunculifolia. For this purpose, extracts of aerial parts (BD-C), tricomial wash (BD-L) and roots (BD-R) of B. dracunculifolia were obtained by maceration. The extracts were submitted to different chromatographic techniques, including high-speedy countercurrent chromatography (HSCCC) furnishing nine isolated compounds. The extracts and isolated compounds were evaluated regarding their antimicrobial activity by the broth microdilution method, according to the Clinical and Laboratory Standards Institute, and regarding their sanitizing activity according to Standard Operating Procedure No. 65.3210.007 (INCQS, 2011), developed by the National Institute for Quality Control in Health (INCQS) - Oswaldo Cruz Foundation (FIOCRUZ). In the antimicrobial evaluation the BD-C extract showed minimum inhibitory concentration (MIC) values of 200 and 100 µg/mL against S. aureus and T. mentagrophytes, respectively. BD-L extract showed MIC value of 200 µg/mL against S. aureus. The isolated compounds caffeic acid (MBC 2.22 µM), ferulic acid (MBC 2.06 µM) and baccharin (MBC 0.27 µM) showed significant inhibitory activity against S. aureus. All B. dracunculifolia isolated compounds were active with exception of aromadrendin-4´-O-methyl-ether for T. mentagrophytes. Additionally, isosakuranetin was active against S. choleraesuis (MIC 1.4 µM). Regarding the sanitizing activity, the hydroalcoholic solution containing 0.2% of B. dracunculifolia extract in 40 ºGL ethanol was effective in eliminating the microbial contamination on all carrier cylinders and against all microorganisms evaluated in the recommended exposure time of 10 min. Therefore, B. dracunculifolia has potential for the development of sanitizing agents to be used in hospitals, food manufactures and homes.

Brazilian southeast brown propolis: gas chromatography method development for its volatile oil analysis, its antimicrobial and leishmanicidal activities evaluation

INTRODUCTION

Propolis is widely used in folk medicine, and many factors can affect its chemical composition, including abiotic factors that can influence plants and bees. Therefore, analytical methods are powerful techniques in the quality control of such products.

OBJECTIVE

Develop and validate an analytical method for quantifying volatile compounds in Brazilian brown propolis, and evaluate its biological activities.

METHODS

A gas chromatography flame ionisation detector (GC-FID) analytical method was validated, attending the parameters of international validation guidelines as ANVISA 2017 and ICH 2005, for quantification of compounds present in volatile oils from propolis. Evaluation of cytotoxic, antimicrobial, and leishmanicidal activities of the oil.

RESULTS

The compounds 1,8-cineole, terpinen-4-ol, α-copaene, β-caryophyllene, γ-muurolene, nerolidol, spathulenol, and γ-palmitolactone were isolated from the volatile fraction of a Brazilian brown propolis and used in the method validation. All the validation parameters of the method were satisfactory. The volatile fraction displayed a significant leishmanicidal activity, with half maximal inhibition concentration (IC₅₀ ) = 21.3 μg/mL against amastigote forms and IC₅₀ = 25.1 μg/mL against promastigote forms of Leishmania amazonensis. The oil also displayed an antibacterial effect by inhibiting the growth of Streptococcus mutans and Staphylococcus aureus at 25 μg/mL and 50 μg/mL, respectively, but it was not cytotoxic against AGP-01, He-La and CHO-K1cell lines, with IC₅₀ > 100 μg/mL.

CONCLUSION

The GC-FID method can be a useful tool in the quality control of propolis material. The southeast brown propolis showed a high chemical complexity in its volatile fraction, which displayed leishmanicidal activity and bactericidal activity.

Artepillin C as an outstanding phenolic compound of Brazilian green propolis for disease treatment: A review on pharmacological aspects

Propolis is a viscous resin consisting of plant material (shoots, flowers, and plant exudates), salivary secretions and waxes produced by Apis mellifera bees. Its popular use aroused the interests of scientific research, which proved to be a potential source of various bioactive substances. The chemical composition of propolis depends on several factors, such as the different types of plant sources collected by bees, geographic origin, and the time of year in which they are produced, but it is known that phenolic represent the main bioactive constituents of propolis. Baccharis dracunculifolia DC (Asteraceae) is the most important botanical source of propolis and a native to southeastern Brazil. It is widely known as the green propolis because of its deep green color. One of its major phenolic acids is artepillin C (Art-C), a diprenyl-p-hydroxycinnamic acid derivative. This review aims to provide a comprehensive summary of the pharmacological effects of Art-C. The limited number of publications on this topic over the past two decades have been collected from databases and summarized. Numerous biological activities have been described for the Art-C, such as gastroprotective, anti-inflammatory, antimicrobial, antioxidant, antitumor. This article describes aspects of occurrence, synthesis, biological activities and pharmacokinetic approaches.

Propolis, Bee Honey, and Their Components Protect against Coronavirus Disease 2019 (COVID-19): A Review of In Silico, In Vitro, and Clinical Studies

Despite the virulence and high fatality of coronavirus disease 2019 (COVID-19), no specific antiviral treatment exists until the current moment. Natural agents with immune-promoting potentials such as bee products are being explored as possible treatments. Bee honey and propolis are rich in bioactive compounds that express strong antimicrobial, bactericidal, antiviral, anti-inflammatory, immunomodulatory, and antioxidant activities. This review examined the literature for the anti-COVID-19 effects of bee honey and propolis, with the aim of optimizing the use of these handy products as prophylactic or adjuvant treatments for people infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Molecular simulations show that flavonoids in propolis and honey (e.g., rutin, naringin, caffeic acid phenyl ester, luteolin, and artepillin C) may inhibit viral spike fusion in host cells, viral-host interactions that trigger the cytokine storm, and viral replication. Similar to the potent antiviral drug remdesivir, rutin, propolis ethanolic extract, and propolis liposomes inhibited non-structural proteins of SARS-CoV-2 in vitro, and these compounds along with naringin inhibited SARS-CoV-2 infection in Vero E6 cells. Propolis extracts delivered by nanocarriers exhibit better antiviral effects against SARS-CoV-2 than ethanolic extracts. In line, hospitalized COVID-19 patients receiving green Brazilian propolis or a combination of honey and Nigella sativa exhibited earlier viral clearance, symptom recovery, discharge from the hospital as well as less mortality than counterparts receiving standard care alone. Thus, the use of bee products as an adjuvant treatment for COVID-19 may produce beneficial effects. Implications for treatment outcomes and issues to be considered in future studies are discussed.

Artepillin C: A comprehensive review of its chemistry, bioavailability, and pharmacological properties

Artepillin C (ARC), a prenylated derivative of p-coumaric acid, is one of the major phenolic compounds found in Brazilian green propolis (BGP) and its botanical source Baccharis dracunculifolia. Numerous studies on ARC show that its beneficial health effects correlate with the health effects of both BGP and B. dracunculifolia. Its wide range of pharmacological benefits include antioxidant, antimicrobial, anti-inflammatory, anti-diabetic, neuroprotective, gastroprotective, immunomodulatory, and anti-cancer effects. Most studies have focused on anti-oxidation, inflammation, diabetic, and cancers using both in vitro and in vivo approaches. Mechanisms underlying anti-cancer properties of ARC are apoptosis induction, cell cycle arrest, and the inhibition of p21-activated kinase 1 (PAK1), a protein characterized in many human diseases/disorders including COVID-19 infection. Therefore, further pre-clinical and clinical studies with ARC are necessary to explore its potential as intervention for a wide variety of diseases including the recent pandemic coronaviral infection. This review summarizes the comprehensive data on the pharmacological effects of ARC and could be a guideline for its future study and therapeutic usage.

The Anti-tumor Effects of p-Coumaric Acid on Melanoma A375 and B16 Cells

Background: Existing research shows that p-coumaric acid (p-CA) can inhibit the proliferation of a variety of tumor cells in vitro. However, there are no reports on the anti-tumor effects of p-CA on melanoma cells. In this study, the inhibitory effects of p-CA on mouse melanoma B16 and human melanoma A375 cells are reported, and the related mechanisms are investigated. Methods: CCK-8 assay was used to detect the effects of p-CA on cell vitality, colony formation assay was used to observe the effects on cell proliferation, Hoechst 33,258 staining was used to observe the morphology of apoptotic cells, flow cytometry was used to detect the effects on apoptosis and the cell cycle, and western blot was used to measure the levels of cell cycle- and apoptosis-related signaling pathway proteins. Results: p-CA significantly inhibits cell proliferation of A375 and B16 cells in a dose-dependent manner and obviously induced cell morphological changes. p-CA arrested A375 cells in the S phase by downregulating the cell cycle-related proteins Cyclin A and CDK2, and arrested B16 cells in the G0-G1 phase through downregulating the cell cycle-related proteins Cyclin E and CDK2. In addition, p-CA significantly promoted apoptosis of A375 and B16 cells. Furthermore, p-CA significantly upregulated the levels of Apaf1 and Bax and downregulated the levels of Bcl-2, and subsequently increased the levels of cytoplasmic cytochrome c (Cyto-c), cleaved caspase-3, and cleaved caspase-9, leading to apoptosis in A375 and B16 cells. Conclusion: p-CA can significantly inhibit the proliferation of human and mouse melanoma cells in vitro. Our research is a step in the development of anti-melanoma drugs.