Is propolis safe as an alternative medicine?

Instant clot forming and antibacterial wound dressings: Achieving hemostasis in trauma injuries with S-nitroso-N-acetylpenicillamine-tranexamic acid-propolis formulation

Wound infection and excessive blood loss are the two major challenges associated with trauma injuries that account for 10% of annual deaths in the United States. Nitric oxide (NO) is a gasotransmitter cell signaling molecule that plays a crucial role in the natural wound healing process due to its antibacterial, anti-inflammatory, cell proliferation, and tissue remodeling abilities. Tranexamic acid (TXA), a prothrombotic agent, has been used topically and systemically to control blood loss in reported cases of epistaxis and combat-related trauma injuries. Its properties could be incorporated in wound dressings to induce immediate clot formation, which is a key factor in controlling excessive blood loss. This study introduces a novel, instant clot-forming NO-releasing dressing, and fabricated using a strategic bi-layer configuration. The layer adjacent to the wound was designed with TXA suspended on a resinous bed of propolis, which is a natural bioadhesive possessing antibacterial and anti-inflammatory properties. The base layer, located furthest away from the wound, has an NO donor, S-nitroso-N-acetylpenicillamine (SNAP), embedded in a polymeric bed of Carbosil®, a copolymer of polycarbonate urethane and silicone. Propolis was integrated with a uniform layer of TXA in variable concentrations: 2.5, 5.0, and 7.5 vol % of propolis. This design of the TXA-SNAP-propolis (T-SP) wound dressing allows TXA to form a more stable clot by preventing the lysis of fibrin. The lactate dehydrogenase-based platelet adhesion assay showed an increase in fibrin activation with 7.5% T-SP as compared with control within the first 15 min of its application. A scanning electron microscope (SEM) confirmed the presence of a dense fibrin network stabilizing the clot for fabricated dressing. The antibacterial activity of NO and propolis resulted in a 98.9 ± 1% and 99.4 ± 1% reduction in the colony-forming unit of Staphylococcus aureus and multidrug-resistant Acinetobacter baumannii, respectively, which puts forward the fabricated dressing as an emergency first aid for traumatic injuries, preventing excessive blood loss and soil-borne infections.

Therapeutic potential of propolis in alleviating inflammatory response and promoting wound healing in skin burn

Burns can cause inflammation and delayed healing, necessitating alternative therapies due to the limitations of conventional treatments. Propolis, a natural bee-produced substance, has shown promise in facilitating burn healing. This literature review provides a comprehensive overview of propolis' mechanisms of action, wound-healing properties, and its application in treating skin burns. Propolis contains bioactive compounds with antimicrobial, antioxidant, and anti-inflammatory properties, making it a promising candidate for managing skin burn injuries. It helps prevent infections, neutralize harmful free radicals, and promote a well-balanced inflammatory response. Moreover, propolis aids in wound closure, tissue regeneration, collagen synthesis, cellular proliferation, and angiogenesis, contributing to tissue regeneration and remodeling. The article discusses various propolis extracts, extraction methods, chemical composition, and optimized formulations like ointments and creams for burn wound treatment. Considerations regarding dosage and safety are addressed. Further research is needed to fully understand propolis' mechanisms, determine optimal formulations, and establish suitable clinical dosages. Nevertheless, propolis' natural origin and demonstrated benefits make it a compelling avenue for burn care exploration, potentially complementing existing therapies and improving burn management outcomes.

Anti-MRSA and Biological Activities of Propolis Concentrations Loaded to Chitosan Nanoemulsion for Pharmaceutics Applications

Propolis is a naturally occurring substance with beneficial properties; bees produce it from various plant sources, and it is an anti-inflammatory and therapeutic resinous substance. This study aimed to enhance the biological features of propolis extract by loading it onto active film. Firstly, extraction was performed using three solvent systems, and their total phenolic, flavonoid, and antioxidant activity was measured. Propolis ethanol extract (EEP) was evaluated for phenolic fraction content and then chosen to prepare a chitosan-loaded emulsion with several concentrations. The antibacterial, anti-mycotic, and anti-mycotoxigenic properties of the extract and nanoemulsion were assessed. PPE's cytotoxicity and nanoemulsion were evaluated using brine shrimp and cell line assays. Results indicate higher phenolic (322.57 ± 4.28 mg GAE/g DW), flavonoid (257.64 ± 5.27 mg QE/g DW), and antioxidant activity of the EEP. The phenolic fraction is distinguished by 18 phenolic acids with high p-hydroxybenzoic content (171.75 ± 1.64 µg/g) and 12 flavonoid compounds with high pinocembrin and quercetin content (695.91 ± 1.76 and 532.35 ± 1.88 µg/g, respectively). Phenolic acid derivatives (3,4-Dihydroxybenzaldehyde, 3,4-Dihydroxyphenol acetate, and di-methoxy cinnamic) are also found. Concentrations of 50, 100, 150, and 200 ng EEP loaded on chitosan nanoemulsion reflect significant antibacterial activity against pathogenic bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA) and toxigenic fungi, particularly Fusarium. Among the four EEP-loaded concentrations, the nanoemulsion with 150 ng showed outstanding features. Using a simulated medium, 150 and 200 ng of EEP-loaded chitosan nanoemulsion concentrations can stop zearalenone production in Fusarium media with complete fungi inhibition. Also, it reduced aflatoxins production in Aspergillus media, with fungal inhibition (up to 47.18%). These results recommended the EEP-chitosan application for pharmaceutics and medical use as a comprehensive wound healing agent.

The benefits of propolis in periodontal therapy. A scoping review of preclinical and clinical studies

ETHNOPHARMACOLOGICAL RELEVANCE

The treatment of periodontal disease (PD) is aimed at adequate control of bacterial plaque. In many patients mechanical methods are unable to eliminate this plaque leading to the need for adjuvant chemical products. Propolis is a natural product that has demonstrated therapeutic properties and has shown to be effective as an anti-inflammatory and antibacterial agent in dentistry.

AIM OF THE STUDY

Considering the beneficial effects of propolis on various oral conditions, this study aimed to review, update and summarize the available evidence on the benefits of propolis in in vitro studies, animal models, and human clinical trials on non-surgical periodontal therapy.

MATERIALS AND METHODS

An electronic search in three databases was performed up to December 2021. The search strategy included the terms "propolis" and "periodontal disease" to identify relevant studies on the potential advantages of propolis in periodontal therapy in in vitro studies, animal models, and human clinical trials.

RESULTS

The search yielded 538 results, discarding 459 studies that did not clearly meet the inclusion criteria. A total of 42 studies were included: 18 in vitro, one animal, and 23 randomized clinical trials. In vitro studies have demonstrated that propolis has antimicrobial activity against periodontal pathogens and clinical studies have reported its use as an adjunct to non-surgical periodontal therapy. The clinical effects of propolis have been reported in conjunction with prophylaxis, polishing, and scaling and root planing (SRP). It has shown to have anti-plaque activity and improve gingival health. Propolis was found to be more effective in improving clinical parameters than conventional treatment (SRP alone) and demonstrated similar efficacy in treating chronic periodontitis compared to positive controls. Only one study reported an allergic reaction.

CONCLUSION

The evidence available on the benefits of propolis in in vitro studies, animal models, and clinical trials suggests that propolis could be a promising adjunct to conventional therapy of gingivitis and periodontitis. However, further studies are needed to determine its superiority to other therapies in the treatment of PD.

Flavonoids as Potential Wound-Healing Molecules: Emphasis on Pathways Perspective

Wounds are considered to be a serious problem that affects the healthcare sector in many countries, primarily due to diabetes and obesity. Wounds become worse because of unhealthy lifestyles and habits. Wound healing is a complicated physiological process that is essential for restoring the epithelial barrier after an injury. Numerous studies have reported that flavonoids possess wound-healing properties due to their well-acclaimed anti-inflammatory, angiogenesis, re-epithelialization, and antioxidant effects. They have been shown to be able to act on the wound-healing process via expression of biomarkers respective to the pathways that mainly include Wnt/β-catenin, Hippo, Transforming Growth Factor-beta (TGF-β), Hedgehog, c-Jun N-Terminal Kinase (JNK), NF-E2-related factor 2/antioxidant responsive element (Nrf2/ARE), Nuclear Factor Kappa B (NF-κB), MAPK/ERK, Ras/Raf/MEK/ERK, phosphatidylinositol 3-kinase (PI3K)/Akt, Nitric oxide (NO) pathways, etc. Hence, we have compiled existing evidence on the manipulation of flavonoids towards achieving skin wound healing, together with current limitations and future perspectives in support of these polyphenolic compounds as safe wound-healing agents, in this review.

Disinfectant effects of Brazilian green propolis alcohol solutions on the Staphylococcus aureus biofilm of maxillofacial prosthesis polymers

STATEMENT OF PROBLEM

Brazilian green propolis may be an alternative product that reduces the development of a microbial biofilm on the polymers used for maxillofacial prostheses. However, its effects as a disinfectant have not been fully established.

PURPOSE

The purpose of this in vitro study was to investigate the effects of Brazilian green propolis alcohol solutions against the Staphylococcus aureus biofilm on polymers used in maxillofacial prostheses, the maxillofacial silicone elastomer (MDX4-4210), and specific acrylic resins for ocular prostheses.

MATERIAL AND METHODS

A total of 324 disk-shaped specimens (3×10 mm) of each material were fabricated. All specimens were contaminated with S. aureus (10⁸ cells/mL) to assess the antibiofilm activity of immersion solutions and protocols. Thus, 162 specimens of each material were randomly distributed and equally divided into 5 groups of disinfectants and 1 control group: 3 separate groups of 2.5%, 5%, and 10% propolis alcohol solutions, 1 group of 5% propolis alcohol gel, a positive control group of 2% chlorhexidine gluconate, and a negative control group of distilled water. Specimens (n=9) were disinfected by immersion for 5, 10, and 15 minutes and immersed in culture medium for 24 hours. Any notable turgescence in the final medium was considered indicative of a biofilm. The effects of disinfectants were analyzed by a turbidity assay and by scanning electron microscopy. Data were analyzed descriptively.

RESULTS

The final medium with specimens disinfected with 10% propolis alcohol solution showed no turbidity, indicating constant efficacy against the S. aureus biofilm. Similarly, these findings were observed in the 2% chlorhexidine gluconate group. Scanning electron microscopy images demonstrated that the surface of the polymers treated with 10% propolis alcohol solution did not show bacterial colonies.

CONCLUSIONS

Disinfection with 10% green propolis alcohol solution was effective in eliminating the S. aureus biofilm from specimens of maxillofacial elastomer and N1 acrylic resin specific to ocular prostheses by immersion for 5 minutes.

Propolis: chemical diversity and challenges in quality control

Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with region and season. This inherent chemical variability presents several challenges to its standardisation and quality control. The present review was aimed at highlighting marker compounds for different types of propolis, produced by the species Apis mellifera, from different geographical origins and that display different biological activities, and to discuss strategies for quality control. Over 800 compounds have been reported in the different propolises such as temperate, tropical, birch, Mediterranean, and Pacific propolis; these mainly include alcohols, acids and their esters, benzofuranes, benzopyranes, chalcones, flavonoids and their esters, glycosides (flavonoid and diterpene), glycerol and its esters, lignans, phenylpropanoids, steroids, terpenes and terpenoids. Among these, flavonoids (> 140), terpenes and terpenoids (> 160) were major components. A broad range of biological activities, such as anti-oxidant, antimicrobial, anti-inflammatory, immunomodulatory, and anticancer activities, have been ascribed to propolis constituents, as well as the potential of these compounds to be biomarkers. Several analytical techniques, including non-separation and separation methods have been described in the literature for the quality control assessment of propolis. Mass spectrometry coupled with separation methods, followed by chemometric analysis of the data, was found to be a valuable tool for the profiling and classification of propolis samples, including (bio)marker identification. Due to the rampant chemotypic variability, a multiple-marker assessment strategy considering geographical and biological activity marker(s) with chemometric analysis may be a promising approach for propolis quality assessment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-022-09816-1.

Effectiveness of propolis in maintaining oral health: a scoping review

Background

Research has revealed that periodontal diseases are caused by inflammation that results from a dysbiosis of the oral microbiome where oral bacteria multiply into larger communities referred to as dental biofilm. To help control this overgrowth of bacteria, a variety of toothpastes, dentifrices, and mouthwashes have been developed. Although not as common in North American toothpastes, propolis as an active ingredient in dentifrices has begun to emerge, as laboratory studies have suggested it has anti-inflammatory, immunomodulatory, antioxidant, antimicrobial, and antidiabetic properties. The purpose of this scoping review was to explore the literature on the effectiveness of propolis in maintaining oral health.

Methods

This review used the following criteria: Population: studies involving healthy humans; Intervention: propolis in the form of toothpaste, dentifrice, and mouthwash; Comparison: fluoride, chlorohexidine, and placebo; Outcomes: plaque and gingival indices, improvement in oral hygiene, and inhibition of bacteria. Relevant research articles were selected from Web of Science, PubMed, MEDLINE, and Scopus databases using the search parameter "propolis[tw] AND (toothpaste*[tw] OR dentifrice*[tw] OR mouthwash*[tw])". Only original articles published after 2009 and written in the English language were included.

Results

A total of 19 original papers met the criteria and showed varying levels of success achieved with the use of propolis. It was responsible for a significant lowering of specific plaque and gingival indices, inhibited the growth of bacteria, reduced oral flora diversity, and consistently improved periodontal condition, oral hygiene, and oral health.

Conclusion

Propolis may play a role in initiating, sustaining, and maintaining oral health as its desirable properties have the potential to improve various oral hygiene related indices.

Indian Propolis Little Known and More to Explore for Dental Applications: A Review

Aim:

The present trend in health care is toward the use of natural products for curing diseases. “Propolis” or bees wax is a natural, nontoxic resinous material collected by bees from exudates and buds of the plant. It has many beneficial biological and pharmacological properties such as antimicrobial, anti-inflammatory, antifungal, antiviral, and anticancer activities. Propolis is widely applied in dentistry as an anticariogenic agent, hypersensitivity reducing agent, and endodontic disinfection to name a few. The diverse phytochemical constituents of propolis are responsible for its valuable properties. Considering its vast potential, propolis has gained the attention of many researchers. The aim of this study is to offer a comprehensive evidence which will enable the readers and researchers to appreciate the prospects of the application of Indian propolis in present-day dentistry.

Material and Methods:

In vitro and in vivo studies on Indian propolis and its application in dentistry searches were performed in PubMed, Scopus, and Cochrane library databases up to December 2020.

Results:

The search identified 31 records; 12 full-text articles which met the eligibility criteria were assessed. Based on the results of in vitro studies, further in vivo studies need to be carried out to prove the feasibility of Indian propolis as an anticariogenic agent, a desensitizing agent, and an intracanal irrigant/medicament in the field of dentistry.

Conclusion:

Indian propolis has shown an immense amount of potentiality which demands for more clinical research to have sufficient evidence-based literature for future usage in oral health care.

Down-regulation of complement genes in lipopolysaccharide-challenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis

Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 μg/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 μg/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 μg/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

The Cardiovascular Therapeutic Potential of Propolis-A Comprehensive Review

Simple Summary

Propolis, also described as bee glue, is a natural component made up of a resinous mixture of honeybee compounds from multiple botanical sources. The literature has demonstrated a variety of medicinal properties attributed to propolis due to its chemical complexity. However, the positive effects of propolis on cardiovascular health have gained little coverage. Therefore, we aimed to provide an accurate and up-to-date review of the main cardiovascular health benefits of propolis. In particular, we intend to establish the key varieties of propolis and pharmacological compounds with the therapeutic effects that are most encouraging, as well as the physiological processes by which those advantages are accomplished. The Brazilian green and red varieties reveal the greatest number of beneficial activities among the varieties of propolis studied. While much of the cardiovascular beneficial effects appear to derive from the cumulative actions of several compounds working via multiple signaling mechanisms, some individual compounds that may enhance the existing therapeutic arsenal have also shown significant results. It is also worth exploring the prospect of using propolis as food supplements.

Abstract

Owing to its chemical richness, propolis has a myriad of therapeutic properties. To the authors’ knowledge, this is the first comprehensive review paper on propolis to focus exclusively on its major effects for cardiovascular health. The propolis compound varieties with the most promising therapeutic benefits and their respective physiological mechanisms will be discussed. Propolis displays an anti-atherosclerotic activity, attained through modulation of the plasma lipid profile and through stabilization of the fatty plaque by inhibiting macrophage apoptosis, vascular smooth muscle proliferation and metalloproteinase activity. The antihypertensive effects of propolis probably arise through the combination of several mechanisms, including the suppression of catecholamine synthesis, stimulation of endothelium-dependent vasorelaxation and vascular anti-inflammatory activity. The anti-hemostatic activity of propolis is attributed to the inhibition of platelet plug formation and antifibrinolytic activity. By inhibiting the secretion of proangiogenic factors, propolis suppresses endothelial cell migration and tubulogenesis, exerting antiangiogenic activity. The antioxidant and anti-inflammatory activities are responsible for protection against vascular endothelial and cardiomyocyte dysfunction, mostly by the prevention of oxidative stress. Among the reviewed propolis varieties, the Brazilian green and red varieties show the largest number of beneficial activities. Further research, especially preclinical, should be conducted to assess the cardiovascular benefits of the given varieties with different compositions.

A standardized polyphenol mixture extracted from poplar-type propolis for remission of symptoms of uncomplicated upper respiratory tract infection (URTI): A monocentric, randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

The most common symptoms of mild upper respiratory tract infections (URTIs) are sore throat, muffled dysphonia, and swelling and redness of the throat, which result from the inflammation process following acute bacterial or viral infection.

HYPOTHESIS/PURPOSE

As propolis is a natural resinous substance traditionally used to maintain oral cavity and upper respiratory tract health due to its antimicrobial and anti-inflammatory properties, the aim of this study is to evaluate the efficacy of an oral spray based on poplar-type propolis extract with a known and standardized polyphenol content, on the remission of the symptoms associated with mild uncomplicated URTIs.

STUDY DESIGN

A monocentric, randomized, double-blind, placebo-controlled clinical trial was performed.

METHODS

This study was conducted in 122 healthy adults who had perceived mild upper respiratory tract infections. Participants, randomly assigned to receive either propolis oral spray (N = 58) or placebo (N = 64), underwent four visits (baseline = t0, after 3 days = t1 and after 5 days = t2 and after a follow-up of 15 days = t3) in an outpatient setting. Propolis oral spray total polyphenol content was 15 mg/ml. The dosage was 2-4 sprays three times/day (corresponding to 12-24 mg of polyphenols/day), for five days. The duration of the study was 8 weeks.

RESULTS

After 3 days of treatment, 83% of subjects treated with propolis oral spray had remission of symptoms, while 72% of subjects in the placebo group had at least one remaining symptom. After five days, all subjects had recovered from all symptoms. This means that resolution from mild uncomplicated URTIs took place two days earlier, instead of taking place in five days as recorded in the control group. There was no relationship between the ingestion of propolis oral spray or placebo and adverse reactions.

CONCLUSION

Propolis oral spray can be used to improve both bacterial and viral uncomplicated URTI symptoms in a smaller number of days without the use of pharmacological treatment, leading to a prompt symptom resolution.

Propolis-induced exclusion of colloids: Possible new mechanism of biological action

Propolis is a natural product originating from life activity of honeybees. It exhibits wide range of biological properties applicable in medicine, the food industry, and cosmetics. Chemically, propolis is a complex and variable mixture with more than 300 identified biologically active components. Propolis's many health-promoting effects are attributed to different biochemical mechanisms, mediated by often-concerted actions of some of its many constituents. Propolis is considered safe and biocompatible. Yet due to its intrinsic complexity, standardization of propolis preparations for medical use as well as prediction of e.g. pathogen-specific interactions becomes a non-trivial task. In this work we demonstrate a new physical mechanism of propolis action, largely independent of specific nuances of propolis chemistry, which may underlie some of its biological actions. We show that propolis-bearing surfaces generate an extensive exclusion zone (EZ) water layer. EZ is an interfacial region of water capable of excluding solutes ranging from ions to microorganisms. Propolis-generated EZ may constitute an effective barrier, physically disabling the approach of various pathogens to the propolis-functionalized surfaces. We suggest possible implications of this new mechanism for propolis-based prevention of respiratory infections.

In vivo evaluation of pharmacological properties of Argentine stingless bee geopropolis

Background

Propolis is a natural product that has been widely utilized as medicine and dietary supplement because of its broad biological activities. However, although meliponide hive products have many advantages, meliponiculture has not yet become popular in Argentina, and few scientific studies on its chemical composition and/or its bioactive properties were reported, so the use of stingless bee propolis Argentine in popular medicine continues to be based on empirical knowledge.

Our work aims to evaluate in vivo anti-inflammatory, antitussive and expectorant activities, and acute toxicity of the Argentine geopropolis ethanol extracts of two stingless bee’s species, Scaptotrigona jujuyensis Schrottky and Tetragonisca fiebrigi Schwarz. Wistar male rats were used for all in vivo studies. Anti-inflammatory activities were evaluated through carrageenan-induced edema and cotton pellet-induced granuloma formation. Antitussive activity was assessed against ammonia-induced cough. Expectorant activity was measured by volume of phenol red in the rats’ tracheas. The extract doses tested were 125, 250, 500, and 1000 mg/kg (p.o.). The safety was evaluated with test of acute toxicity (48 h).

Results

The results showed that S. jujuyensis and T. fiebrigi propolis (1000 mg/kg) significantly reduced the carrageenan-induced edema and cotton pellet-induced granuloma formation 3 h post-dosing. In the ammonia liquor-induced cough, both propolis significantly enhanced the latent period and reduced cough frequency as compared with those of the negative control. However, they did not increase the expulsion of red phenol in the treated rats.

Conclusions

This study shows that ethanol extracts of S. jujuyensis and T. fiebrigi propolis have anti-inflammatory and antitussive effects. These findings would justify the use of geopropolis in medicine as a potential phytotherapeutic product.

Graphical abstract

Lessons from Exploring Chemical Space and Chemical Diversity of Propolis Components

Propolis is a natural resinous material produced by bees and has been used in folk medicines since ancient times. Due to it possessing a broad spectrum of biological activities, it has gained significant scientific and commercial interest over the last two decades. As a result of searching 122 publications reported up to the end of 2019, we assembled a unique compound database consisting of 578 components isolated from both honey bee propolis and stingless bee propolis, and analyzed the chemical space and chemical diversity of these compounds. The results demonstrated that both honey bee propolis and stingless bee propolis are valuable sources for pharmaceutical and nutraceutical development.

Novel Bi-Factorial Strategy against Candida albicans Viability Using Carnosic Acid and Propolis: Synergistic Antifungal Action

The potential fungicidal action of the natural extracts, carnosic acid (obtained from rosemary) and propolis (from honeybees’ panels) against the highly prevalent yeast Candida albicans, used herein as an archetype of pathogenic fungi, was tested. The separate addition of carnosic acid and propolis on exponential cultures of the standard SC5314 C. albicans strain caused a moderate degree of cell death at relatively high concentrations. However, the combination of both extracts, especially in a 1:4 ratio, induced a potent synergistic pattern, leading to a drastic reduction in cell survival even at much lower concentrations. The result of a mathematical analysis by isobologram was consistent with synergistic action of the combined extracts rather than a merely additive effect. In turn, the capacity of SC5314 cells to form in vitro biofilms was also impaired by the simultaneous presence of both agents, supporting the potential application of carnosic acid and propolis mixtures in the prevention and treatment of clinical infections as an alternative to antibiotics and other antifungal agents endowed with reduced toxic side effects.

Effectiveness of Different Analytical Methods for the Characterization of Propolis: A Case of Study in Northern Italy

Propolis is used as folk medicine due to its spectrum of alleged biological and pharmaceutical properties and it is a complex matrix not still totally characterized. Two batches of propolis coming from two different environments (plains of Po Valley and the hilly Ligurian–Piedmont Apennines) of Northern Italy were characterized using different analytical methods: Spectrophotometric analysis of phenols, flavones and flavonols, and DPPH radical scavenging activity, HPLC, NMR, HSPME and GC–MS and HPLC–MS Orbitrap. Balsam and moisture content were also considered. No statistical differences were found at the spectrophotometric analysis; balsam content did not vary significantly. The most interesting findings were in the VOCs composition, with the Po Valley samples containing compounds of the resins from leaf buds of Populus nigra L. The hills (Appennines) samples were indeed characterize by the presence of phenolic glycerides already found in mountain environments. HPLC–Q-Exactive-Orbitrap^®–MS analysis is crucial in appropriate recognition of evaluate number of metabolites, but also NMR itself could give more detailed information especially when isomeric compounds should be identified. It is necessary a standardized evaluation to protect and valorize this production and more research on propolis characterization using different analytical techniques.

Hepatoprotective and antineoplastic potencial of red propolis produced by the bees Apis mellifera in the semiarid of Rio Grande do Norte, Brazil

ABSTRACT: The objective of this study was to evaluate the hepatoprotective effect of the honey bee Apis mellifera ethanolic extract of the red propolis, obtained in four municipalities of the Rio Grande do Norte semi-arid region, through an in vitro evaluation of the antineoplastic potential in human hepatic carcinoma (HepG2) and normal cell lines (L929), and from the comet assay in hepatic cell lines (ZF-L hepatocytes) to evaluate the genoprotective potential of the extract. The hepatoprotective effect was also evaluated in vivo by the induction of chronic experimental hepatic lesions in rodents (Rattus norvegicus Berkenhout, 1769), Wistar line, by intraperitoneal administration of thioacetamide (TAA) at the dose of 0.2g/kg. The animals were distributed in the following experimental groups: G1 (control), G2 (treated with 500mg/kg ethanolic extract of propolis), G3 (treated with 500mg/kg of ethanolic extract and TAA) and G4 (treated with TAA). All rats were submitted to serum biochemical, macroscopic, histological and stereological biochemical exams of the liver. It was verified the genoprotective effect of red propolis since the mean damages promoted to DNA in cells tested with the extract were significantly lower than the mean of the positive control damage (hydrogen peroxide). The red propolis extract did not present cytotoxic activity to the tumor cells of human liver cancer, as well as to normal ones. The absence of cytotoxicity in normal cells may indicate safety in the use of the propolis extract. The results of the serum biochemical evaluation showed that the serum levels of the aminotransferase enzymes (AST) did not differ significantly between G1, G2 and G3 when compared to each other. G4 showed significant increase in levels compared to the other groups, indicating that the administration of the extract did not cause liver toxicity, as well as exerted hepatoprotective effect against the hepatic damage induced by TAA. The G3 and G4 animals developed cirrhosis, but in G3 the livers were characterized by the presence of small regenerative nodules and level with the surface of the organ, whereas in G4 the livers showed large regenerative nodules. The livers of the G1 and G2 animals presented normal histological appearance, whereas the livers of the G3 animals showed regenerative nodules surrounded by thin septa of connective tissue, and in G4 the regenerative nodules were surrounded by thick septa fibrous connective tissue. The analysis of the hepatic tissues by means of stereology showed that there was no statistical difference between the percentage of hepatocytes, sinusoids, and collagens in G1 and G2. In G3 the percentage of hepatocytes, sinusoids, and collagen did not differ significantly from the other groups. It was concluded that the ethanolic extract of the red propolis exerted a hepatoprotective effect, because it promoted in vitro reduction of the damage to the DNA of liver cells, antineoplastic activity in human hepatocellular carcinoma cell line (HepG2) and did not exert cytotoxic effect in normal cells or was able to reduce liver enzyme activity and the severity of cirrhosis induced by TAA in vivo.

Antibacterial and antioxidant assessment of cellulose acetate/polycaprolactone nanofibrous mats impregnated with propolis

Cellulose acetate (CA) electrospun nanofibers are one of the most practical cellulosic material which normally applied as carriers for drug delivery and wound healing systems. In this study, CA and polycaprolactone (PCL) was applied to fabricate the electrospun nanofibrous for wound dressing application. Propolis is a resin-like macromolecule produced by honeybees from the buds and diverse plants. Among many applications of this macromolecule, it has been occasionally employed directly to the skin for wound healing applications. Herein, owing to the significance of propolis, CA/PCL nanofibers were impregnated with a propolis-extracted solution to reach antibacterial and antioxidant mat. The scanning electron microscopy (SEM) images revealed that electrospinning of 10% (w/w) CA along with 14% (w/w) PCL produced excellent nanofibers compared to the resultant nanofibers. Hydrophobicity/hydrophilicity nature of CA/PCL mats was measured using water contact-angle method before and after treatment with NaOH. The nanofibrous mats exhibited a high water absorption capacity of about 400%. Antioxidant effect was measured by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay and propolis-CA/PCL presented a high antioxidant activity. Additionally, propolis-CA/PCL mats showed antibacterial activity against both the Gram-positive and Gram-negative bacteria. In conclusion, our results have confirmed that the propolis-impregnated CA/PCL mats have provided an appropriate surface for wound healing system.

Phytochemical Findings Evidencing Botanical Origin of New Propolis Type from North-West Argentina

Propolis samples from north-west Argentina (Amaicha del Valle, Tucumán) were evaluated by palynology, FT-IR spectra, and RP-HPTLC. In addition, the volatile fraction was studied by HS-SPME-GC/MS. The botanical species most visited by Apis mellifera L. near the apiaries were collected and their RP-HPTLC extracts profiles were compared with propolis samples. In addition, GC/MS was performed for volatile compounds from Zuccagnia punctata Cav. (Fabaceae). FT-IR spectra and RP-HPTLC fingerprints of propolis samples showed similar profiles. In RP-HPTLC analyses, only Z. punctata presented a similar fingerprint to Amaicha propolis. The major volatile compounds present in both were trans-linalool oxide (furanoid), 6-camphenone, linalool, trans-pinocarveol, p-cymen-8-ol, and 2,3,6-trimethylbenzaldehyde. Potential variations for the Amaicha del Valle propolis volatile fraction as consequence of propolis sample preparation were demonstrated.

Investigation of the anti-TB potential of selected propolis constituents using a molecular docking approach

Human tuberculosis (TB), caused by Mycobacterium tuberculosis, is the leading bacterial killer disease worldwide and new anti-TB drugs are urgently needed. Natural remedies have long played an important role in medicine and continue to provide some inspiring templates for drug design. Propolis, a substance naturally-produced by bees upon collection of plant resins, is used in folk medicine for its beneficial anti-TB activity. In this study, we used a molecular docking approach to investigate the interactions between selected propolis constituents and four ‘druggable’ proteins involved in vital physiological functions in M. tuberculosis, namely MtPanK, MtDprE1, MtPknB and MtKasA. The docking score for ligands towards each protein was calculated to estimate the binding free energy, with the best docking score (lowest energy value) indicating the highest predicted ligand/protein affinity. Specific interactions were also explored to understand the nature of intermolecular bonds between the most active ligands and the protein binding site residues. The lignan (+)-sesamin displayed the best docking score towards MtDprE1 (−10.7 kcal/mol) while the prenylated flavonoid isonymphaeol D docked strongly with MtKasA (−9.7 kcal/mol). Both compounds showed docking scores superior to the control inhibitors and represent potentially interesting scaffolds for further in vitro biological evaluation and anti-TB drug design.

Flavonoid Extract from Propolis Inhibits Cardiac Fibrosis Triggered by Myocardial Infarction through Upregulation of SIRT1

The flavonoid extract from propolis (FP) has been shown to protect against heart injury induced by isoproterenol. However, the effect of FP on cardiac fibrosis after myocardial infarction (MI) as well as the underlying mechanisms is not known. In the present study, we used biochemical and histological approaches to examine the effects of FP on MI-induced cardiac fibrosis and the related mechanisms in a rat MI model and in angiotensin II- (Ang II-) treated rat cardiac fibroblasts (CFs). In vivo, MI was generated by ligation of the left anterior descending coronary artery of rats, which remained for 4 weeks. Rats were randomly divided into the sham, MI, FP (12.5 mg/kg/d), and MI+FP groups. We found that FP treatment improved heart function, reduced cardiac fibrosis, and downregulated the expression of fibrosis-related factors including collagen I, collagen III, matrix metalloproteinase-2 (MMP-2), MMP-9, transforming growth factor-β1 (TGF-β1), and p-Smad2/3, which coincided with the upregulated expression of silent information regulator 1 (SIRT1) in the hearts of MI rats. Our in vitro experiments showed that FP inhibited the proliferation and migration of primary cultured rat CFs and downregulated the expression of the above-mentioned fibrosis-related factors in Ang II-stimulated CFs. In addition, FP can decrease ROS production induced by MI and Ang II in vivo and vitro. Notably, silencing SIRT1 counteracted the FP-induced effects on CFs treated with Ang II. We conclude that FP inhibits MI-induced cardiac fibrosis through SIRT1 activation and that FP represents a potential promising drug for the treatment of MI patients in the clinic.

Propolis and Its Potential to Treat Gastrointestinal Disorders

There are a number of disorders that affect the gastrointestinal tract. Such disorders have become a global emerging disease with a high incidence and prevalence rates worldwide. Inflammatory and ulcerative processes of the stomach or intestines, such as gastritis, ulcers, colitis, and mucositis, afflict a significant proportion of people throughout the world. The role of herbal-derived medicines has been extensively explored in order to develop new effective and safe strategies to improve the available gastrointestinal therapies that are currently used in the clinical practice. Studies on the efficacy of propolis (a unique resinous aromatic substance produced by honeybees from different types of species of plants) are promising and propolis has been effective in the treatment of several pathological conditions. This review, therefore, summarizes and critiques the contents of some relevant published scientific papers (including those related to clinical trials) in order to demonstrate the therapeutic value of propolis and its active compounds in the treatment and prevention of gastrointestinal diseases.

Potential role of propolis in wound healing: Biological properties and therapeutic activities

Propolis is a resinous mixture that honey bees collect from the tree buds, sap flows, or other botanical sources. The chemical composition of propolis varies and depends on the geographical area, time of collection, seasonality, illumination, altitude, and food availability during propolis exploitation. The goal of this review is to discuss important concepts including mechanisms of action and therapeutic activities of propolis. The PubMed, ScienceDirect, and Cochrane Library databases were searched for the literature published from January the 1st 2000 to October the 1st 2017. Sixteen animals and three clinical studies were included. A quantitative and qualitative review was performed on the clinical trials and the animal studies were comprehensively overviewed. In this study, the clinical trials have been combined and the results were provided as meta-analysis. Propolis is a non-toxic natural product; however some cases of allergy and contact dermatitis to this compound have been described mainly among beekeepers. An important factor in impaired wound healing is biofilm formation; propolis as an anti-microbial agent can reduce biofilm generation and result in accelerated healing processes. Most of the in vivo studies on various wound models suggested the beneficial roles of propolis on experimental wound healing and this has also been approved in the clinical trial studies. However, there is a lack of information concerning, dose, side effects and clinical effectiveness of propolis on wounds. As the effectiveness of propolis between different products is variable, more characterizations should be done and future investigations comparing different propolis based products and characterization of their specific roles on different models of wounds are highly appreciated.

Standardization, anti-carcinogenic potential and biosafety of Indian propolis

Background

Propolis from apiculture is known for wide range of medicinal properties owing to its vast chemical constituents including polyphenols, flavonoids and anticancer agent Caffeic acid phenethyl ester (CAPE).

Objectives

The objective of the study was to extract and standardize Indian propolis (IP) with respect to selected markers by newly developed High performance liquid chromatography (HPLC) method, to evaluate in vitro and in vivo anticancer activity and biosafety of Indian propolis.

Materials and methods

IP was extracted, optimized and standardized using a newly developed and validated HPLC method for simultaneous estimation of caffeic acid, apigenin, quercetin and CAPE. The standardised ethanolic extract of IP (EEIP) was screened for in vitro cytotoxicity using sulforhodamine B (SRB) assay, in vivo anti-carcinogenic effect against Dalton’s Lymphoma ascites (DLA) cells, hemolytic effect and pesticide analysis.

Results

The EEIP was found to contain more amount of total flavonoids (23.61 ± 0.0452 mg equivalent of quercetin/g), total polyphenolics (34.82 ± 0.0785 mg equivalent of gallic acid/g) and all selected markers except caffeic acid compared to all other extracts. EEIP showed better anti-cancer potential than CAPE on MCF-7 and HT-29 cell line and significant (p < 0.01) in vivo anti-carcinogenic effects against DLA in comparison with 5-fluorouracil. EEIP was found to be non-hemolytic.

Conclusion

From in vitro cytotoxicity, in vivo anti-carcinogenicity and biosafety studies it can be concluded that the standardized EEIP is safe and can be considered for further development as a biomedicine.

Molecular mechanism of cardol, isolated from Trigona incisa stingless bee propolis, induced apoptosis in the SW620 human colorectal cancer cell line

Background

Cardol is a major bioactive constituent in the Trigona incisa propolis from Indonesia, with a strong in vitro antiproliferative activity against the SW620 colorectal adenocarcinoma cell line (IC₅₀ of 4.51 ± 0.76 μg/mL). Cardol induced G₀/G₁ cell cycle arrest and apoptotic cell death. The present study was designed to reveal the mechanism of cardol’s antiproliferative effect and induction of apoptosis.

Methods

Changes in cell morphology were observed by light microscopy. To determine whether the mitochondrial apoptotic pathway was involved in cell death, caspase-3 and caspase-9 activities, western blot analysis, mitochondrial membrane potential, and intracellular reactive oxygen species (ROS) levels were assayed.

Results

Changes in the cell morphology and the significantly increased caspase-3 and caspase-9 activities, plus the cleavage of pro-caspase-3, pro-caspase-9 and PARP, supported that cardol caused apoptosis in SW620 cells within 2 h after treatment by cardol. In addition, cardol decreased the mitochondrial membrane potential while increasing the intracellular ROS levels in a time- and dose-dependent manner. Antioxidant treatment supported that the cardol-induced cell death was dependent on ROS production.

Conclusion

Cardol induced cell death in SW620 cells was mediated by oxidative stress elevation and the mitochondrial apoptotic pathway, and these could be the potential molecular mechanism for the antiproliferative effect of cardol.

External Use of Propolis for Oral, Skin, and Genital Diseases: A Systematic Review and Meta-Analysis

Objective. The aim of this review is to provide the available evidence on the external use of propolis (EUP) for oral, skin, and genital diseases. Method. We searched twelve electronic databases for relevant studies up to June 2016. Randomized clinical trials (RCTs) were included and analysed. Results. Of the 286 articles identified, twelve potentially relevant studies met our inclusion criteria. A meta-analysis of two studies on recurrent oral aphthae (ROA) indicated that there were no significant differences in total effective rate (TER) for pain disappearance between EUP and placebo groups (RR = 1.96, 95% CI = 0.97-3.98, and P = 0.06). In two studies on skin diseases, the combined treatment of EUP with other interventions revealed significant effects on the duration of treatment or TER. In one study on genital diseases, EUP showed significant differences in genital herpes outcome measures compared to placebo. Conclusions. Our results on the effectiveness of EUP for treating oral, skin, and genital diseases are not conclusive because of the low methodological qualities and small sample sizes. Further well-designed randomized controlled trials, with high quality and large samples for specific disorders, must be conducted to obtain firm conclusions.

Oral Health of Patients Treated with Acrylic Partial Dentures Using a Toothpaste Containing Bee Product

This study was carried out to investigate the influence of a propolis and tee tree oil-containing hygienic agent on selected oral health parameters, oral microflora, and the condition of periodontal health. Thirty-seven patients who underwent oral rehabilitation with a removable acrylic denture were selected and randomly assigned into two groups: study group (A) which received a newly formulated propolis and tee tree oil-containing toothpaste or a control group (C) without an active ingredient. API, S-OHI, and mSBI were assessed in three subsequent stages. During each examination swabs were employed for microbiological inoculation: in the study group after 4 weeks use of the active toothpaste showed a decrease in the number of isolated microorganisms. In the control group, after 4 weeks use of the toothpaste without active ingredients resulted in increase in the number of the isolated microorganisms. Improvements in hygiene and the condition of periodontium were observed in patients using active toothpastes. In the study group the oral flora diversity was reduced by the decrease in the number of cultured microorganism species, while in the control group an increase in the number of cultured microorganisms and their species was observed.

The Influence of Ethanolic Extract of Brazilian Green Propolis Gel on Hygiene and Oral Microbiota in Patients after Mandible Fractures

Maintenance of proper oral hygiene by dental plaque elimination is one of the most important factors affecting the healing process in postoperative oral wounds. Propolis is a substance produced by bees. Ethanolic extract of propolis has bactericidal, fungicidal, anti-inflammatory, and antioxidative properties. Moreover, it can scavenge free radicals. The purpose of this paper is to demonstrate the efficacy of a gel containing 3% of ethanolic extract of Brazilian green propolis (EEP-B) when used for maintaining oral hygiene in patients with postoperative oral mucosal wounds. The hygiene was assessed using API, OHI, and SBI followed by microbiological examinations. The patients were divided into two groups. Group 1 consisted of those who used a gel containing EEP-B for oral hygiene, and group 2 consisted of those who used a gel without EEP-B. Although improved oral hygiene was noted in both groups, the improvement was markedly greater in the group using gel containing EEP-B. Summing up the results of microbiological examinations, EEP-B has beneficial effect on mouth microflora in postoperative period. Propolis preparations used for oral hygiene allow eliminating microorganisms of pathogenic character and physiological flora microorganisms considered as being opportunistic, with no harmful influence on physiological microflora in oral ecosystem.

The Effects of NBF Gingival Gel Application in the Treatment of the Erosive Lichen Planus: Case Report

The therapy of erosive lichen planus (ELP) has been particular problem in the treatment of oral lesions. This case of ELP in male patient 29 years old was treated with topic application of the NBF gingival gel, three times a day after meal, previously rinsed with Clorhexidine gluconate 0.12%. After 5 days of treatment, initial improvements were recorded, and after two weeks of application of the NBF gingival gel we observed significant improvement. Clinical monitoring after the fifth day showed mild epithelialization of the eroded mucosa, yet still present erythematous base of the lesion. After the second week the erythema area was significantly reduced and the eroded surfaces of the mucosa were minimal, measured less than 0.5 mm. After the third week there were no erosions to detect on the oral mucosa, yet still present vague redness, which completely pulled after the fourth week. Treatment ended after the fifth week when the topical application of the NBF gingival gel was terminated, and therapy was done, and clinically achieved effects remained stable even after the third month of the treatment. Topic application of the NBF gingival gel with ELP patients showed positive clinical effects in relatively short time period.

The comparative effect of propolis in two different vehicles; mouthwash and chewing-gum on plaque accumulation and gingival inflammation

Objective:

In general, chemical plaque agents have been used in mouthwashes, gels, and dentifrices. In some situations, application of mouthwashes and dentifrices can be difficult. Therefore, different approaches for oral health-care have been needed. The aim of this study was to evaluate the effect of propolis chewing-gum compared to propolis-containing mouthwash on gingival inflammation and plaque accumulation on patients that refrained from daily oral hygiene procedures for 5 days.

Materials and Methods:

10 college students with systemically healthy and very good oral hygiene and gingival health were included in this randomized, single-blind, crossover 5-day plaque regrowth with a 3-day washout period clinical study. After plaque scores were reduced to zero, participants were asked to refrain from oral hygiene procedures and allocated to either propolis mouthwash or chewing-gum group. Chewing-gum was performed after meals 3 times a day for 20 min mouthwash group was instructed to rinse mouthwash 2 times a day for 1 min. On day 5, the clinical periodontal measurements containing plaque and gingival indexes were taken from the participants.

Results:

The both plaque and gingival indexes of propolis mouthwash group were significantly lower than that of the propolis chewing-gum group (P = 0.005).

Conclusion:

It was demonstrated that the propolis mouthwash was more effective than the propolis chewing gum on the plaque inhibition and the gingival inflammation.

Influence of the toothpaste with brazilian ethanol extract propolis on the oral cavity health

Propolis-based therapeutic agents represent this potential for the development of new drugs in dental care. The aim of a clinical-cohort study was to determine the influence of application of toothpaste enriched with Brazilian extract of propolis (EEP) on health status of oral cavity. Laboratory analysis was conducted in order to assess the chemical composition of EEP including total phenolic compounds, the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, ABTS radical cation scavenging activity, and FRAP assay. Clinical research involved two groups of subjects comprising 32 adult patients, with assessment based on the preliminary evaluation of the state of their marginal periodontium. The investigation of oral health indices API, OHI, and SBI and microbiological examination of oral microflora were also carried out. Results obtained indicated time-dependent microbial action of EEP at 50 mg/L concentration, with antimicrobial activity against Gram-positive bacteria. The total decrease of API, OHI, and SBI mean values was observed. Hygienic preparations with 3% content of Brazilian ethanol extract of green propolis (EEP) efficiently support removal of dental plaque and improve the state of marginal periodontium.

Important developments in romanian propolis research

The most important developments in propolis analysis and pharmacological properties are discussed. In order to help in the Romanian propolis standardization, different methodologies for chemical composition analysis (UV-VIS, HP-TLC, and HPLC-DAD) are reviewed using new approaches and software (fuzzy divisive hierarchical clustering approach and ChromQuest software) and compared with international studies made until now in propolis research. Practical applications of Romanian propolis in medicinal therapy and cosmetics are reviewed, and quality criteria for further standardization are proposed.

A Comparison between Antibacterial Activity of Propolis and Aloe vera on Enterococcus faecalis (an In Vitro Study)

Removing the bacteria, including Enterococcus faecalis, from the root canal is one of the important aims in endodontic treatment.We aimed to compare the antibacterial activity of Chlorhexidine with two natural drugs. The antibacterial activities of three different propolis extracts (alcohol concentrations: 0, 15, 40%) and Aloe vera gel on E. faecalis were compared using three methods: disk diffusion, microdilution and direct contact test. In addition to the above bacterium, the Aloe vera gel effect on Staphylococcus aureus and Streptococcus mutans was evaluated. Disk diffusion test revealed that propolis ethanolic extracts (the alcohol concentration of 15 and 40%) and Aloe vera gel have antibacterial activities but aqueous extract of propolis did not show any effect in this test. The MICs for propolis ethanolic extracts, Aloe vera gel and aqueous extract of propolis (0% alcohol) were 313 µg/ml, 750 µg/ml, 2250 µg/ml, and ≥ 500 µg/ml respectively, much higher than the Chlorhexidine one. In direct contact test, contrary to Aloe vera, all three propolis extracts showed antibacterial effects on E. faecalis. The Aloe vera gel also showed significant antibacterial effect on S.aureus and S.mutans. The hydroalcoholic extracts of propolis and Aloe vera gel had antibacterial effects on E. faecalis, however, propolis is more potent than Aloe vera. The antibacterial effect of Aloe vera on S. aureus and S. mutans is low (MIC ≥ 2250 µg/ml). Appropriate concentrations of alcoholic extracts of propolis and some fractions of Aloe vera gel might be good choices for disinfecting the root canal in endodontic treatments.

Chrysin: a histone deacetylase 8 inhibitor with anticancer activity and a suitable candidate for the standardization of Chinese propolis

Chinese propolis (CP) is a natural product collected by honeybees and a health food raw material. Previous studies have shown that CP exhibits a broad spectrum of biological activities including anticancer, antioxidant, antibacterial, anti-inflammatory, and antiviral activities. The focuses of the present study were the standardization of CP and the possible mechanisms of its active anticancer ingredients. Nine samples of CP were collected from different locations in China. Analyses of the CP samples revealed that all 9 had similar chemical compositions. Parameters analyzed included the CP extract dry weight, total phenolic content, and DPPH free radical scavenging activities. The active anticancer ingredient was isolated, characterized against human MDA-MB-231 breast cancer cells, and identified as chyrsin, a known potent anticancer compound. Chrysin is present at high levels in all 9 of the CP samples, constituting approximately 2.52% to 6.38% of the CP extracts. However, caffeic acid phenethyl ester (CAPE), another potent active ingredient is present in low levels in 9 samples of CP, constituting approximately 0.08% to 1.71% of the CP extracts. Results from analyses of enzymatic activity indicated that chrysin is a histone deacetylase inhibitor (HDACi) and that it markedly inhibited HDAC8 enzymatic activity (EC(50) = 40.2 μM). In vitro analyses demonstrated that chrysin significantly suppressed cell growth and induced differentiation in MDA-MB-231 cells. In a xenograft animal model (MDA-MB-231 cells), orally administered chrysin (90 mg/kg/day) significantly inhibited tumor growth. Despite the geographical diversity of the 9 samples' botanical origins, their chemical compositions and several analyzed parameters were similar, suggesting that CP is standardized, with chrysin being the major active ingredient. Overall, in vitro and in vivo data indicated that chrysin is an HDAC8 inhibitor, which can significantly inhibit tumor growth. Data also suggested that chrysin might represent a suitable candidate for standardization of CP.