Brazilian Propolis: Nature’s Liquid Gold with Anti-Inflammatory and Anticancer Potential

Abstract

Brazilian propolis is a natural bee product with a unique and diverse chemical composition. It is especially rich in phenols and terpenoids that show a range of significant biological properties. Due to the growing scientific interest, its strong anti-inflammatory and anticancer activity has been highlighted. In vitro and in vivo studies demonstrate its potential to modulate inflammatory pathways by inhibiting pro-inflammatory cytokines, such as tumour necrosis factor (TNF-α) and interleukin 6 (IL-6), as well as by regulating oxidative stress. Additionally, active compounds in Brazilian propolis have the potential to inhibit tumour cell proliferation, induce apoptosis and modulate the tumour microenvironment. Depending on the botanical source and region of occurrence, different types of Brazilian propolis are distinguished, including green, red and brown, which differ in composition and biological activity. Green propolis, rich in artepilin C and phenolic acids, shows strong anti-inflammatory and anticancer properties. Red propolis contains isoflavones and quercetin that enhance its antioxidant and immunomodulatory activities. Brown propolis, rich in cinnamic acids and benzophenones, exerts cytotoxic effects against certain lines of cancer cells. This article discusses the current state of knowledge on the mechanisms of action of different types of Brazilian propolis and their potential uses as supportive therapy in inflammatory and cancerous diseases in combination with nanotechnology.

1. Introduction

Propolis, also known as bee glue, is a naturally occurring viscous substance produced by honeybees. It is composed of resins, sap and mucilage comprising various parts of plants, including tree bark, leaves and flower buds, with apian enzymatic proteins and beeswax. Propolis is utilised by honeybees to polish the inner walls of hives and repair damage and to maintain a constant humidity and temperature inside them. Additionally, the substance provides a colony with protection from pathogenic microorganisms, parasites and predators. At low temperatures, propolis is fragile and stiff but when the temperature rises, it becomes softer, more flexible and stickier. Depending on the origin and period of storage, propolis can have a distinct herbal smell and it comes in a variety of shades, including green, yellow, red and brown [1].

The term “propolis” has Greek roots. The “pro” prefix means defence and the parent word “polis” refers to a community and city or, in this context, a beehive [2]. The long history of therapeutic uses of propolis is as old as the application of other bee products and dates back to 300 BC at least. The first people to discover the beneficial properties of propolis were ancient Greeks, Egyptians and Romans who applied it in the treatment of wounds and as an antiseptic agent [3]. It was also used as a beauty product, a preservative and sanitiser for wounds and tumours, and for mummification. In medieval Eastern Europe and the Middle East, propolis was widely applied as a natural medication. At the beginning of the modern era, it became the subject of research that mainly focused on identifying its chemical composition [4].

In Brazil, fourteen types of propolis have been documented and categorised according to their geographic location, physicochemical features and botanical origin [5]. In tropical and subtropical regions, due to differences in vegetation, propolis has a distinct appearance, chemical composition and properties that distinguish it from poplar propolis. The main botanical sources of Brazilian propolis are Baccharis dracunculifolia DC., Dalbergia ecastophyllum (L.) Taub., Araucaria angustifolia (Bertol.) Kuntze, and Eucalyptus citriodora (Hook.) K.D.Hill & L.A.S.Johnson. [6]. The green, red and brown varieties are the most studied types of Brazilian propolis. They are also important for the Brazilian economy due to their health-promoting properties and exports to other countries, like Japan [7].

Brazilian propolis exhibits a variety of biological properties, producing anticancer, anti-inflammatory, antioxidant, antimicrobial and antiparasitic effects [8,9,10,11]. The anti-inflammatory and anticancer properties represent some of the most well-documented activities of Brazilian propolis, simultaneously addressing two major global health challenges. Current statistics highlight the increasing incidence of cancer worldwide in both men and women, which emphasizes the need for greater efforts aimed at prevention, early detection and effective treatment of the disease. The World Health Organization (WHO) estimates that the number of cancer cases may reach 35.3 million by 2050 [12].

One of the factors closely associated with cancer development is chronic inflammation, which increases the risk or progression of cancer and involves genetic instability [13]. Having considered the close relationship between persistent inflammation and cancer development, the identification and activity of compounds that exert both effects is of high importance. Brazilian propolis presents a very rich chemical profile. Compounds found in its composition include, among others, polyisoprenylated benzophenones, xanthones, triterpenoids, chalcones, flavonols [14], flavonoid glycosides, prenylated flavonoids [15], phenolic acids and artepilin C, which only confirm its biological properties [5].

The efficacy of Brazilian propolis depends on its solubility in various solvents varying in polarity. At present, ethanol is the main solvent used to obtain propolis extracts; however, the use of nanotechnology can potentially allow for hydrophobic substances, such as propolis, to be dispersible in water [16]. Nanotechnology plays an important role in increasing the efficiency of the delivery of active ingredients to cells. The use of nanoparticles as carriers of drugs/active substances allows the precise delivery of therapeutic agents directly into cells, thereby minimising side effects and increasing the effectiveness of therapy [17]. When implementing this technique, it is possible to optimise the biological activity of propolis by encapsulating or using nanoparticles in combination with the active compounds present in Brazilian propolis [18,19]. The aim of this study was to comprehensively summarise the anti-inflammatory and anticancer properties of red, green and brown Brazilian propolis, used either alone or in combination with nanoparticles, evaluated by both in vitro and in vivo studies.

2. Experimental Paper Selection Criteria (Study Design)

The aim of this study was to investigate anti-inflammatory and anticancer properties of Brazilian propolis based on its in vivo and in vitro effects. The research and analysis of data were conducted using the resources of NCBI-PubMed and Google Scholar databases from years 2010–2025. The selection of sources for this review was performed in January 2025. The following keywords were used: Brazilian propolis, anti-inflammatory/anticancer/antioxidant properties of Brazilian propolis, in vivo/in vitro models of anti-inflammatory/anticancer/antioxidant effect of Brazilian propolis, Green Brazilian propolis, Red Brazilian propolis, Brown Brazilian propolis, nanoparticles with Brazilian propolis, nanoencapsulation of Brazilian propolis, Brazilian propolis extracts. The search term Brazilian propolis identified 661 results on NCBI-PubMed, although only those from the past 15 years were included (524 results). During the course of this work, some articles were excluded. The gradual process of selection and elimination of source materials is presented in Figure 1.

Figure 1. Visual demonstration of the screening method for this study (created with canva.com).

3. Brazilian Propolis: Unique Properties and Economic Significance

In the past few decades, propolis has gained significant popularity among the community of researchers. It attracted the attention of scientists as early as in the 1950s; however, it was the revelation of its healing properties that brought it widespread recognition and aroused a lot of interest [20]. After decades of thorough examination of the chemical composition of propolis, more than 300 phytochemicals have been identified in samples collected globally [20]. The chemical composition of propolis from different global regions and locations varies [21] depending on the season, the geographical factors, climate and regional botanical composition [22], which highlights the variety of vegetation in a specific area [21]. Propolis has been used as a multifaceted remedy since the ancient times and, in some countries, still remains one of the most often used medications [23]. Its versatility has been a subject of pharmacological and chemical studies for the last 30 years [23].

Regional classification of propolis samples allowed researchers to identify multiple types of propolis, each of them different in terms of medical or chemical properties and origin [23]. Poplar type propolis has buds of poplar trees (mainly the black poplar) as the main floral source and it is representative of propolis sourced from temperate zones all over the world, especially Europe [23], but also North America, non-tropical regions of Asia, New Zealand and even Africa [24]. Romanian propolis, apart from Populus species, has been reported to also be derived from Quercus, Aesculus, Ulmus, Picea, Salix and Fraxinus spp. Another commonly known variety of propolis, the Chinese type, also mainly originates from poplars; however, its unique nature is partly influenced by the surrounding environment as it is collected in mild climate conditions occurring in Central and East China [25]. Another type, Pacific propolis, also referred to as Macaranga, stems from Macaranga spp. and is mostly collected in Taiwan and Okinawa [24]. Mediterranean propolis, derived from Cupressus plants, is found in Malta, Creta and Sicily [24]. Apart from the aforementioned examples, other varieties of propolis, such as Turkish, Uruguayan, Polish, Nepalese, and Eucalyptus [24], have been classified.

Propolis has been found to have antibacterial, antioxidative, antifungal, anti-inflammatory and anticarcinogenic properties [26,27]. Due to the differences in chemical composition of particular types of propolis, it is rather surprising that most variants show similar biological activity. The only exception identified so far is European propolis which has been confirmed to have allergenic properties [23]. Among the identified types of propolis, the Brazilian variant is especially known for its exclusive botanical origin, content of exceptional bioactive compounds and versatile therapeutic potential. Based on the classification criteria, which include geographical origin, chemical composition, physicochemical characteristics and floral source of Brazilian propolis [28,29], 14 types of this bee product have been distinguished [30]. Due to its diverse properties, unique chemical content and heterogenous floral and geographical origin, Brazilian propolis has drawn the attention of researchers and experts in the pharmaceutical field. Its rising popularity over the years is clearly presented in Figure 2, which shows the increasing trend based on the number of articles and reviews on Brazilian propolis and its derivatives available in the PubMed database. Duplicates and articles incorrectly assigned by the search engine were excluded.

Figure 2. Bar chart showing the number of articles on Brazilian propolis and its derived substances over the years (2010–2024); based on the PubMed database of scientific articles.

The most popular variety is green Brazilian propolis, mainly originating from Baccharis dracunculifolia DC., with artepillin C being its characteristic constituent [29]. Recently, a new type of green Brazilian propolis has been discovered. Unlike the formerly classified variety, primarily collected in the southeastern region of Brazil, the newly identified type is mostly found in the northern part of this country, with its floral origin being Mimosa tenuiflora (Willd.) Poir. [14]. Red Brazilian propolis is produced on mangroves from a red exudate of Dalbergia ecastaphyllum (L.) Taub. or, in the Atlantic Forest, of Symphonia globulifera. It has also been established that red Brazilian propolis occasionally originates from the Clusia species [14]. Both biomes are in proximity to Brazilian coastal regions [14]. Its signature compounds are vestitol, neovestitol and methylvestitol (isoflavonoids) [31].

Brazilian propolis from the southern region is often referred to as brown Brazilian propolis. Its distinct chemical profile indicates its complex origin, including Baccharis dracunculifolia DC., Populus alba L. and Araucaria angustifolia (Bertol.) Kuntze [14]. Depending on its floral origination, the chemical content may differ; however, the components commonly found are artepillin C, luteolin-5-O-methyl ether, dipertenes and pinocembrin [14]. Geographical locations and vegetative sources of the selected types of propolis are presented in Figure 3.

Figure 3. Geographical locations of Brazilian propolis production and the floral origin; created with BioRender.com.

Differences in the Brazilian propolis chemome compared to other types of propolis result in the outstanding properties of this specific variant. Compared to the Chinese type, Brazilian propolis has a higher content of artepillin C, chlorogenic acid and isochlorogenic acid A, which demonstrates a strong anti-inflammatory effect [25]. Both varieties show strong free-radical scavenging activity [25]. Compared to Egyptian, Saudi, Omani, Chinese and Bulgarian varieties, Brazilian propolis contains the highest amount of phenolic compounds [1]. It is also reported to contain a considerable amount of fat, which makes it a potentially valuable source of unsaturated fatty acids [1]. The chloroform fraction of Brazilian propolis has antibacterial properties against S. aureus and Streptococcus mutans [32]. Methanol, acetate and hexane fractions of Brazilian red propolis also show antibacterial effects on S. aureus, S. epidermides and Pseudomonas aeruginosa [32]. Other types of Brazilian propolis, such as yellow, black, dark, etc., have been classified [14]. However, their commercial production and popularity level are far lower than those of the green and red varieties [14], which are valuable nutraceutical products on the global market [20].

According to the data provided by the Brazilian Institute of Geography and Statistics, red Brazilian propolis, from the mangrove forests in the state of Alagoas and its extracts have the Appellation of Origin label. It indicates the geographical origin of products and services considered significant for a particular region. It also confirms unique characteristics of a specific product related to its origin, thus providing reliable information both on the product and the local culture it represents [33]. The latest published data show that Brazil exported 41,721 kg of Brazilian propolis for $5,401,643 [28]. The most commercially valuable samples are marked by meagre contributions of resin from alternative plant sources.

Being purely of floral origin, green Brazilian propolis is characterized by its vivid green colour and stiffness [14]. Production and export of Brazilian propolis allow local beekeepers to achieve a source of income and equal access to resources for people in rural areas. This creates a good chance of achieving the goals proposed by the United Nations Sustainable Development Goals (UNSDGs) since the work of the rural community translates into a decent income, which also proves that agriculture (including beekeeping) may be a profitable occupation [34]. This could help the agricultural industry, i.e., a significant part of the Brazilian economy, to prevail and reduce rural emigration [34]. Data obtained from the Brazilian Institute of Geography and Statistics and collected in the 2017 Census of Agriculture survey indicate that 4.5% of landless producers are beekeepers who produce honey and propolis for trade, with 23.4% of them settled in Minas Gerais, a state known for a great concentration of Baccharis dracunculifolia DC., locally called “vassourinha-do-campo” or “alecrim-do-campo”, i.e., the main floral source of green Brazilian propolis [35].

4. Secondary Metabolites of Brazilian Propolis

Brazilian propolis is renowned for its great diversity of colours, chemical composition and bioactive properties depending on the geographic region and plant sources. The most well-known types include green, red, and brown propolis, each linked to specific botanical origins. Apart from those, yellow and black propolis have been reported to occur in some regions, though they are less studied [14]. Green propolis mainly originates from Baccharis dracunculifolia DC. and is rich in artepillin C, a key bioactive compound. Red propolis, derived from Dalbergia ecastaphyllum (L.) Taub. and Symphonia globulifera (L.f.), is recognised for its high content of isoflavonoids and polyprenylated benzophenones. Brown propolis has a more complex composition, often containing terpenes, flavonoids, and phenolic acids, and is derived from Araucaria angustifolia (Bertol.) Kuntze, Pinus spp., and Eucalyptus spp. Yellow and black propolis have also been identified in certain regions of Brazil, however, they are less studied, and their unique chemical profiles are still being explored. These colour variations reflect differences in plant resins collected by bees, which has an impact on the biological activity and commercial value of each type.

The diversity of Brazilian propolis makes it a powerful natural product with numerous medicinal and industrial applications. Literature data indicate that green propolis is particularly rich in prenylated phenolic compounds that are largely responsible for its well-documented biological effects. The most characteristic compound of green propolis is artepillin C, whose presence has been demonstrated by Pires and Castro, Sun et al., and de Figueiredo et al. This type of propolis also contains baccharin, caffeic acid, chlorogenic acid, culifolin, kaempferide, kaempferol, and p-coumaric acid [36,37,38,39]. As for Brazilian red propolis, the most abundant bioactive constituents identified by Daugsch et al. were formononetin, isoliquiritigenin, pinocembrin, biochanin A, luteolin, quercetin, pinobanksin, daidzein, liquiritigenin and rutin. Other researchers have also identified the presence of formononetin, vestitol, neovestitol, and cinnamic acid derivatives [40,41,42,43,44,45,46,47,48,49,50,51,52,53]. The last well-identified type of Brazilian propolis is brown propolis which, according to Gomes et al., contains compounds such as caffeic acid phenethyl ester (CAPE), kaempferol, chrysin, quercetin, apigenin, ferulic acid, pinocembrin, galangin, vanillic acid and p-coumaric acid. Also, when studying the components of this natural product, de Oliveira Dembogurski observed the presence of 5-O-E-caffeoylquinic acid, naringenin, drupanin and baccharin, among others [44].

Apart from the bioactive compounds described above, Brazilian propolis contains a variety of volatile oils, the composition of which varies depending on the regional flora. The main volatile compound identified in Brazilian green propolis is nerolidol. Quintino et al. also found carvacrol, acetophenone, spathulenol, (E)-nerolidol and β-caryophyllene in the green variant [54]. Additionally, Fernandes-Silva et al. identified the allyl ester of 3-prenylcinnamic acid and spathulenol [55]. Brazilian red propolis is rich in phenylpropanoids, including elemicin and methyleugenol [56]. In brown propolis, volatile compounds, such as acetophenone, nerolidol and spathulenol, have been identified as major constituents [57]. The volatile oil of southeastern brown propolis contains 1,8-cyneol, terpinen-4-ol and various sesquiterpenes [54]. These volatile oils exhibit a wide range of beneficial biological properties. Brazilian propolis is an extremely rich treasure trove of bioactive compounds that vary according to type (green, red or brown) and contribute to its potent biological activity extensively utilised by humans in many different ways. Examples of chemical structures are presented in Figure 4.

Figure 4. Chemical structures of selected secondary metabolites of various types of Brazilian propolis. The structures were developed using MolView software (MolView v2.4).

5. Molecular Mechanism and In Vitro and In Vivo Anti-Inflammatory Activity of Different Brazilian Propolis Extracts

Inflammation is a complex defence process in the body triggered in response to various damaging factors such as infection, injury or toxins. Its purpose is to eliminate the destructive agent and repair the affected tissues [45,46]. This process involves a series of reactions at the molecular and cellular level. In response to danger signals, pathogen-associated molecular patterning (PAMP) or damage-associated molecular patterning (DAMP), pattern recognition receptors (PRRs) are activated on the surface of immune cells. This further leads to the activation of signalling pathways such as nuclear factor kappa B (NF-κB), resulting in the production of pro-inflammatory cytokines (e.g., interleukins IL-1, IL-6) and chemotactic factors. These mediators promote the influx of leukocytes to the site of injury, increase vascular permeability and initiate phagocytosis [47,48,49,50,51,52,53]. The mechanism of the anti-inflammatory action of Brazilian propolis involves several aspects: 1. Inhibition of the activity of pro-inflammatory enzymes: Brazilian propolis can inhibit the activity of cyclooxygenase (COX) and lipoxygenase (LOX), enzymes responsible for the synthesis of pro-inflammatory prostaglandins and leukotrienes [4,58]; 2. Modulation of cytokine production: Compounds present in propolis can reduce the secretion of pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-α) and IL-6, leading to a reduction in the inflammatory response [58,59,60]; 3. Antioxidant effects: Propolis neutralises free radicals and reduces oxidative stress, one of the factors promoting inflammation [58,61]; 4. Effects on signalling pathways: Propolis can modulate the activity of signalling pathways such as NF-κB, which affects the expression of genes associated with inflammation [19,58]; 5. Supporting healing processes: Brazilian propolis accelerates the regeneration of damaged tissues, which is important in the context of chronic inflammation [58,59,60]. Pereira et al. have shown that oral administration of the crude extract of brown propolis from Araucaria sp. at a dosage of 90 mg/kg can modify the course of rheumatoid arthritis and inhibit pain through modulation of mechanical sensitivity [62]. The anti-inflammatory effect of propolis may result from its anti-oxidative properties, which include inhibition of oedema formation, cell migration and the expression of NF-kB, as well as preservation of the joint space and normalisation of urea levels [62].

In another study, Hori et al. showed that the presence of artepilin C in Brazilian green propolis extract had an anti-inflammatory effect in vitro and in an in vivo model by reducing IL-1β secretion in mouse macrophages, and this reduction was correlated with a decrease in caspase 1 protease activation. Furthermore, the authors found that the extract, at a concentration of 30 μg/mL, was not toxic to the cells (bone marrow derived macrophages) even after 18 h of treatment [63]. In contrast, de Miranda et al. showed that animals fed with a standard protein diet and treated with the hydroalcoholic extract of lyophilized green Brazilian propolis at a dose of 500 mg/kg had low levels of red blood cells, haemoglobin and haematocrit (which subsequently returned to normal), along with increased monocytes and TNF levels after one week. At the end of the two-week treatment, propolis therapy resulted in a significant recovery of body weight and maintenance of total serum protein levels in the low-protein diet group. The authors also showed that green propolis had an inhibitory effect on inflammation and angiogenesis in animals on a low-protein diet [64]. The potential anti-inflammatory mechanism of Brazilian propolis is presented in Figure 5. Other examples of studies on the anti-inflammatory effect of Brazilian propolis extract in in vitro and in vivo models are shown in Table 1 and Table 2 below.

Figure 5. Visualization of the potential anti-inflammatory mechanisms of Brazilian propolis (created with BioRender.com).

Table 1. In vitro anti-inflammatory activity of various Brazilian propolis extracts.

Type of Propolis	Class of Compounds	Cell Line	Dose	Activity/Mechanism/Effect	Ref.
Brazilian Propolis	Polyphenols	RAW 264.7 macrophages transfected with the NF-kB-pLUC gene	1, 3, 10, 30, 100, and 200 μg/mL	Treatment with an ethanolic extract of Brazilian propolis resulted in a decrease in NF-kB activation and a considerable reduction in the levels of TNF-α. These results confirm the potential use of propolis as an anti-inflammatory compound.	[65]
Brazilian Propolis	-	Human dental pulp cells (hDPCs)	10, 20, 40, 80, and 160 μg/mL	An ethanolic extract of Brazilian propolis caused notable improvement of osteogenic potential and suppressed expression of IL-1β and IL-6 was observed after exposure to LPS. It also had a significant anti-inflammatory and mineralizing effect on hDPCs.	[66]
Brazilian Propolis	-	THP-1 human monocytic cell line	1, 5, 10, 20 and 50 µg/mL	Propolis exerted an anti-inflammatory/antiallergic effect. In the presence of LPS, it induced a higher HMOX-1 expression but inhibited CD86 expression stimulated by DNFB.	[67]
Red Brazilian Propolis	Isoflavonoids (e.g., vestitol and neovestitol) Flavonoids	RAW 264.7 murine macrophages	40–100 μg/mL	An ethanolic extract of red Brazilian propolis inhibited multiple signalling pathways in macrophages involved in the inflammatory process activated by LPS.	[68]
Red Brazilian Propolis	Daidzein, Formononetin, Biochanin	Neutrophils isolated from male, SPF (specific-pathogen free), BALB/c mouse bone marrow	0.01, 0.1 and 1 μg/mL	An ethanolic extract of red Brazilian propolis at 1 μg/mL reduced calcium influx in neutrophils under CXCL2/MIP-2 stimulation. Blocking calcium influx reduced neutrophil chemotaxis.	[69]
Red Brazilian Propolis	Isoflavonoids (e.g., vestitol, neovestitol), Chalcones, Flavanones	Transgenic RAW 264.7 macrophages transfected with the nuclear factor ĸB (NF-ĸB) luciferase	10, 20, and 30 µg/mL	An ethanolic extract of Brazilian red propolis at 30 μg/mL considerably decreased NF-κB activation and TNF-α. The LPS-stimulated macrophages treated with EEBRP showed no reduction in viability at concentrations of up to 30 μg/mL.	[70]
Green Brazilian Propolis	Artepillin C	AMJ-2 macrophages	34, 60, and 120 ng/mL	A green Brazilian propolis hydroalcoholic extract reduced the TNF-α level in LPS-stimulated macrophage culture.	[71]
Green Brazilian Propolis	-	Human gingival fibroblasts (HGF-1 cells)	1, 10, and 20 μg/mL	An ethanolic extract of green Brazilian propolis (EEBP) stimulated human gingival fibroblasts to secrete high levels of acidic FGF-1 and caused a decrease in E-selectin secretion by HGF-1 cells. Artepillin C and other various compounds (such as flavonoids) in EEBP may have an anti-inflammatory effect and accelerate the process of wound healing.	[72]
Green Brazilian Propolis	Phenolics (mainly artepillin C, kaempferide and their derivatives), Flavonoids	Murine macrophage J774A.1 cell line	5–50 μg/mL	An ethanolic extract of green Brazilian propolis exerted intense antioxidant activity and considerably inhibited the production of ROS, RNS, NO, cytokine IL-1 α, IL-1 β, IL-4, IL-6, IL-12p40, IL-13, TNF-α, G-CSF, GM-CSF, MCP-1, MIP-1 α, MIP-1 β, and RANTES in stimulated J774A.1 macrophages.	[9]
Green Brazilian Propolis	Polyphenols (e.g., flavonoids), Cinnamic acids, Triterpenes	Mouse aortic endothelial cells	5, 10 and 20 μg/mL	An ethanolic extract of green Brazilian propolis showed strong anti-inflammatory effects by inhibiting the levels of TNF-α and IL-6 cytokines and protected MAECs through regulation of the expression of ICAM-1, VCAM-1 and MCP-1.	[73]
Green Brazilian Propolis	Polyphenols (e.g., flavonoids), Caffeic acid, p-Coumaric acid, 3,5-Dicafeoyl quinic, 4,5-DCQ, Aromadendrin-4-O-methyl-ether, Drupanin, Artepillin C and Baccharin	Bone marrow cell precursors, naive T cells (CD4+CD44−CD62L+) [C57BL/6 naive female mice]	50 μg/mL	An ethanolic extract of green Brazilian propolis increased PMN-MDSC and Treg cells differentiation in vitro, which indicates that leukocytes decrease asthma associated with Th2 inflammation. The propolis-induced anti-inflammatory effect depends on suppressor myeloid cells and regulatory T cells.	[74]
South Brazilian Propolis	Phenolic acids (gallic acid, caffeic acid, and coumaric acid), Prenylated derivative of cinnamic acid (artepillin C), Flavonoids (pinocembrin)	RAW 264.7 macrophages	0.1, 1, 10, and 100 μg/mL	An ethanolic extract of Brazilian propolis showed anti-inflammatory activity by downregulating NF-kB activation and TNF-α release in RAW 264.7 macrophages, and regulated the expression of a NF-κB-luciferase reporter gene.	[75]

Table 2. In vivo anti-inflammatory activity of various Brazilian propolis extracts.

Type of Propolis	Class of Compounds	Organism	Dose	N	Exposure Time	Activity/Mechanism/Effect	Ref.
Brown Brazilian Propolis	-	Female Wistar rats	Hydroalcoholic extract of Araucaria Brazilian Propolis (HEABP) (30, 100, and 300 mg/kg b.w.)	5 groups of 6 rats + 1 naive group of 6 rats	5 days	The extract of brown Brazilian propolis at doses of 100 and 300 mg/kg prevented TNBS-induced colon damage, prevented GSH depletion, reduced MDA, and restored antioxidant enzyme activity to levels found in the colons of healthy animals. HEBPA can be used in mitigating TNBS-induced colitis in rats.	[76]
Brown Brazilian Propolis	Phenolic compounds	Female adult BALB/c mice	Brown Brazilian hydroalcoholic propolis extract (HPE) (50 mg/kg b.w.)	Control group (n = 4), HCV-2-infected (n = 8), HPE-treated (n = 5), HPE-treated and HSV-2 infected mice (n = 5)	10 days	The hydroalcoholic extract of brown Brazilian propolis treatment reduced extravaginal lesions and the histological damage caused by HSV-2 infection in vaginal tissues of animals. HPE had a protective effect on HSV-2 infected animals by acting on inflammatory and oxidative processes	[77]
Red Brazilian Propolis	Phenolic compounds (liquiritigenin, formononetin, vestitol, neovestitol, medicarpin, 7-O-methylvestitol, and guttiferone E, xanthochymol, and oblongifolin B)	Male Swiss mice (Mus musculus), Wistar Hannover rats (Rattus norvegicus)	Red Brazilian propolis hydroalcoholic extract (12, 24, and 48 mg/kg b.w.)	5 groups of 5 animals	-	The red propolis hydroalcoholic extract exhibited a chemoprotective effect in vivo on DXR-induced genomic instability and on DMH-induced colon carcinogenesis. This effect is related to the anti-inflammatory and antiproliferative activities of red propolis.	[78]
Red Brazilian Propolis	-	SPF (specific pathogen free) BALB/c mice	Red Brazilian propolis alcoholic extract (1, 3 and 10 mg/kg b.w.)	Groups of 5 animals	4 h	The Brazilian red propolis extract is a promising anti-inflammatory natural product whose mechanism seems to act by reducing leukocyte rolling and adhesion; TNF-α, IL-1β, CXCL1/KC and CXCL2/MIP-2 release; and CXCL2/MIP-2-induced chemotaxis and calcium influx.	[69]
Red Brazilian Propolis	Dadzein, Formononetin, Biochanin A	Male Wistar rats	Hydroalcoholic extract (HERP) [x] (topical treatment)	7 groups of 5 animals	6 days	Application of HERP (3.5%) suppressed the clinical signs of inflammation (erythema). HERP has photoprotective activity in a murine model and the mechanisms of protection can be related to the antioxidant and anti-inflammatory characteristics of HERP.	[79]
Red Brazilian Propolis	Flavanones, Isoflavones, Isoflavanes, Polyprenylated acylphloroglucinols	Male Wistar rats	Hydroalcoholic extract (HERP) (100 mg/kg b.w.)	Groups of 6–8 animals	Twice a day for 7 days	The hydroalcoholic extract of red Brazilian propolis displayed a gastric healing effect via reducing oxidative stress and inflammation. Treatment with HERP reduced MPO activity.	[80]
Red Brazilian Propolis		Male Wistar rats	Brazilian red propolis hydroalcoholic solution at 1%, paste containing Brazilian red propolis at 1%	Three experimental groups of six animals		No significant differences in IL-10 or TNF-α levels between collagenase and propolis treatments were observed, suggesting that propolis might act as an anti-inflammatory by maintaining adequate levels of both cytokines, such as collagenase.	[30]
Green Brazilian Propolis	-	Male Wistar rats	Green propolis extract in the form of a powder (500 mg/kg BW, diluted in 5 mL of saline)	Three survival study groups, control group, cecal ligation and puncture groups, metabolic cage study groups	-	The extract reduced inflammation and decreased oxidative stress. It also reduced mortality and protected against the inflammatory response in the kidneys and lungs. That protection might be regulated by decreased expression of the TLR4/NF-κB pathway and consequent attenuation of the inflammatory process.	[81]
Green Brazilian Propolis	Phenolics (e.g., flavonoids)	Male C57BL/6J mice	0.1 mL of green Brazilian propolis ethanolic extract in 0.5% CMC-Na	Control group (n = 8) LPS group (n = 8) LPS + Chinese propolis (n = 12) LPS + green Brazilian propolis (n = 12)	3 days	Prophylactic administration of the green Brazilian propolis ethanol extract reduced the LPS-induced expression of TNF-α, IL-6 and IL-1β, which means it reduced inflammation.	[25]
Green Brazilian Propolis	-	Male Wistar/ST rats	Ethanolic extract of green Brazilian propolis (EEGB) 291 mg/kg per day	Control group (4 animals) EEGBP group (5 animals)	7 days	Administration of 0.3% EEBGP in the diet for 7 days reduced centrilobular hepatocellular necrosis with inflammatory cell infiltration induced by oral administration of APAP (800 mg/kg) and significantly reduced the area of necrosis.	[82]
Green Brazilian Propolis	Polyphenolic compounds	Male Sprague-Dawley rats	300 mg/kg b.w.	4 groups of 8 animals	17 days	BP significantly reduced the colitis disease activity index, prevented significant DSS-induced colonic tissue damage and increased resistance to DSS-induced colonic oxidative stress.	[21]
Green Brazilian Propolis	p-Coumaric acid, Caffeic acid, Cinnamic, Aromadendrin, Isosakuranetin, Artepillin C	Swiss and BALB/c mice	5 mg/kg b.w. Directly extracted or obtained from the concentrated and alkaline hydrolysis of the standardized propolis extract (EPP-AF) solubilized in purified water.	6 groups of 6 animals	6 days	The extract has anti-inflammatory properties via inhibition of proinflammatory cytokines and increasing anti-inflammatory cytokines, preventing amplification of the inflammatory process in the pulmonary site, suggesting an immunomodulatory activity.	[83]

6. Molecular Mechanism and In Vitro and In Vivo Anticancer Effects of Various Brazilian Propolis Extracts

Apoptosis is a programmed cell death regulated by two different pathways, the extrinsic pathway activated by external factors like TNF-related apoptosis-inducing ligand (TRAIL), FasL (Fas ligand), and TNF-α (tumor necrosis factor-α), and the intrinsic or mitochondrial-mediated pathway induced by ROS, which disrupts the mitochondrial membrane potential leading to activation of proapoptotic proteins (p53, Bax/Bad, and cytochrome c) [84]. The anticancer activity of various types of Brazilian propolis and its bioactive compounds is associated with many different mechanisms. These may include apoptosis, leading to reductions in the number of cancer stem cells, modulation of oncogenic pathways, cell cycle arrest, inhibition of tumour cell proliferation, metastasis prevention, matrix metalloproteinase inhibition, anti-angiogenesis, anti-inflammatory effects related to modulating the tumour microenvironment (via modification of macrophage activation and polarisation), and epigenetic regulation and reduction of the harmful side effects of chemotherapy [85,86]. Numerous studies have proven that Brazilian propolis and its compounds trigger both the mitochondrial (intrinsic) and ligand (extrinsic) apoptotic pathways in various tumour cells by modulating several apoptosis-associated signal molecules, such as TNF-alpha/DR, Bax, Bcl-2, Bcl-xL, TRAIL, FasL, p53, caspase and PARP [87]. Brazilian propolis compounds also make cancer cells more susceptible to chemotherapeutic agents by blocking activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) [85,86].

Additionally, by preventing angiogenesis, also known as neovascularisation, Brazilian propolis extract may also have anti-tumour effects [88,89]. This is a multi-step process of developing new blood vessels from existing ones, which is very important in regulating the growth and maintenance of metastatic tumours. This process is very complex and stimulates cell proliferation, migration and invasion, making tumour growth mainly dependent on angiogenesis [88,89,90]. In many diseases characterised by persistent abnormal growth of blood vessels, angiogenesis is disturbed or absent. It may be observed in certain types of cancer and inflammatory diseases [88].

Due to its high content of artepilin C and flavonoids, Brazilian propolis, especially the green variety, has strong anticancer properties. Studies show that it inhibits the proliferation of cancer cells, induces their apoptosis and produces anti-inflammatory and antioxidant effects. It also supports the immune system and may improve the efficacy of cancer treatment while reducing the side effects of chemotherapy and radiotherapy [91,92]. In a study by Buitrago et al., Colombian propolis, rich in phenolic acids and flavonoids, the most representative of which are chrysoeriol-O-methyl-ether, ellagic acid and 3,4-O-dimethylcaffeic acid, showed low levels of cytotoxicity and cell cycle detection in gingival fibroblasts and L929 in the G2/M phase. It may be associated with cytoprotective, proliferative or regenerative effects [93]. Reis et al. demonstrated the cytotoxic effect of Brazilian red propolis extract on the human colon cancer cell line (HCT-116) with an inhibition rate of more than 90%, while for human leukaemia (HL-60) and human prostate cancer (PC3) cell lines, the minimum value identified was 80%. The authors suggest that the composition of Brazilian red propolis varies considerably depending on its geographical origin and the method of extraction, which determines the resulting compounds in the propolis [10]. Machado et al. demonstrated cytotoxic activity of yellow, red, brown and green Brazilian propolis in relation to three cancer cell lines. The green propolis extract showed low inhibition of all lines of cancer cell tested, presenting low cytotoxic potential [HL-60, human ovarian cancer (OVCAR-8) and human glioblastoma cancer (SF-295), HCT-116]. In contrast, the ethanolic extract of brown Brazilian propolis had the highest cytotoxic potential, with an inhibition percentage exceeding 75% in all four cancer cell lines. Yellow Brazilian propolis extract showed high cytotoxic activity only against OVCAR-8 cancer cells [7]. Numerous studies have confirmed the anticancer effect of propolis in both in vitro and in vivo models. The studies are presented in Table 3 and Table 4 below, and potential pathways of action for the anticancer effect of Brazilian propolis are shown in Figure 6.

Table 3. In vitro anticancer effects of Brazilian propolis extracts.

Type of Propolis	Class of Compounds	Cell Lines	Concentration/ Ic50	Activity/Mechanism/Effect	Ref
Hydroalcoholic extract of brown propolis	Gallic acid, catechin, chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, cinnamic acid, crisin	HuH7.5, A549, LLC-MK2	0.25, 0.5, 1.0, 2.5, 5.0, 10, 25, 50, and 100 μg/mL	Hydroalcoholic extract of brown propolis shows selective cytotoxic and antiproliferative activity against human liver carcinoma cells with no cytotoxic effect on normal cells.	[94]
Ethanolic extract of green propolis	-	A549	6.25, 12.5, 25, 50, and 100 μg/mL Ic50—69.17 ± 11.28 μg/mL	Propolis suppressed the proliferation of human lung cancer cells by inducing apoptosis via the intrinsic pathway. The expression of Bcl-XL decreased while Bax and Noxa increased. The upregulation of p21 without p53 was also observed.	[87]
Hydroalcoholic extract of red propolis and fractions	-	Hep-2	5–175 μg/mL Ic50 24 h: Hydroalcoholic red propolis: J fraction: 60.96 ± 4.06 L fraction: 74.60 ± 2.39 Ic50 48 h: Hydroalcoholic red propolis: 57.54 ± 0.98 J fraction: 30.71 ± 3.54 L fraction: 43.73 ± 2.84	Fractions induced apoptosis in Hep-2 cells. Many cells were found in the sub-G1 apoptotic phase.	[95]
Ethanolic extract of red propolis	Liquiritigenin, calycosin, formononetin, isoliquiritigenin, medicarpin, vestitol, neovestitol, 7-O-methylvestitol, oblongifolin B, guttiferone E, xanthochymol	LNCaP, PC-3	1.0, 2.5, 5.0, 10, 20, 25, 50, 75, and 100 μg/mL Ic50 (PC-3 cell line): 53.0 μg/mL	The extract of Brazilian red propolis showed cytotoxic activity against prostate cancer cells (especially against the LNCaP cell line).	[86]
Ethanolic extract of green propolis	Caffeic acid, dihydrocinnamic acid, benzoic acid, flavonoids, triterpenes, prenyl-p-coumaric acid, artepillin C	MCF-7	25, 50, 75, and 100 μg/mL	Green propolis extract, in combination with DTX (docetaxel), showed cytotoxic activity against breast cancer cells. It also decreased MCF-7 cell migration.	[96]
Ethyl acetate extract of red propolis	Methoxyeugenol, cis-asarone, trans isoelemicin, (2S)-7 hydroxyflavanone, chrysin, liquiritigenin, formononetin, medicarpin, vestitol, isovestitol, biochanin A, homopterocarpin, (3S) vestitone, 7-O-methylvestitol, (3S) violanone, guttiferone E, xanthochymol	HT-29, HCT-116, Vero cells	5–150 μg/mL Ic50: Ht-29: 75.15 ± 3.35 HCT-116: 70.81 ± 4.18 Vero: 68.52 ± 4.72	Red propolis extracts and its fractions showed cytotoxic activity against colon cancer cell lines.	[97]
Ethanolic extract of red propolis	Phlobaphene tannins, flavones, flavonols, xanthones, chalcones, aurones, catechins, triterpenoids	SF-295, OVCAR-8, HCT-116	0.09, 0.19, 0.39, 0.78, 1.56, 3.12, 6.25, 12.5, 25, and 50 μg/mL Ic50: SF-295: 34.27 μg/mL OVCAR-8: 28.76 μg/mL HCT-116: 25.26 μg/mL	At higher concentrations, the extract showed high cytotoxicity against human tumour cell lines.	[98]
Hydroalcoholic extracts of red and green propolis	-	HT-29	6.25, 12.5, 25, 50, and 100 μg/mL	The combination of propolis extract and 5-FU (5-fluorouracil) enhanced the cytotoxic effect, especially at higher concentrations. The combination of 5-FU and green propolis showed higher cytotoxicity at all concentrations compared to green propolis alone. For the red propolis extract, the effect was promising, especially in the case of the 100 μg/mL concentration.	[99]
Supercritical extract of green propolis	Artepillin C	HT1080, A549, U2OS	0.01%, 0.1%, 0.5%, and 1% Ic50: 0.2–0.5%	The green propolis extract, containing 9.6% artepillin C, showed high cytotoxicity against cancer cell lines. Green propolis showed anti-migratory activity.	[100]
Hexane-based extract of red propolis	-	HCT-116, PC3	1.56, 3.13, 6.25, 12.5, 25, 50, and 100 μg/mL Ic50 HCT-116: 31.53 μg/mL	Most extracts showed moderate cytotoxic activity. An extract obtained at 70 °C in one 10-min cycle exhibited the strongest cytotoxic effect against tumour cell lines.	[101]
Supercritical extracts of red, green and brown propolis	Artepillin C, p-coumaric acid	B16F10	50 and 100 μg/mL	All the extracts showed significant inhibition of cell proliferation. The best results were observed in red propolis extracts from northeastern regions of Brazil.	[41]

Table 4. In vivo anticancer effect of Brazilian propolis extracts.

Type of Propolis	Class of Compounds	Organism	Dose	N	Exposure Time	Activity/Mechanism/Effect	Ref
Ethanolic extract of green propolis	p-Coumaric acid, artepillin C, baccharin, drupanin	Wistar Hannover rats	0.5% and 2.5%	Six groups of 50 rats; 150 female and 150 male rats	104 weeks	The incidents of pituitary tumours were significantly lower than in the control group. Also, malignant lymphoma/leukaemia were significantly decreased in both male and female rats receiving treatment. Green propolis extract showed antitumourigenic effects on rats.	[102]
Hydroalcoholic extract of red propolis	Daidzein, formononetin, biochanin A, propyl gallate, catechin, epicatechin	Male Swiss mice	10, 50, and 100 mg/kg	Six groups of five mice	26 weeks	The progression of DMBA-induced cancer was retarded by red propolis extract. Red propolis showed chemopreventive activity.	[103]
Alcoholic extract of brown propolis	-	Male Wistar rats	80 mg/kg	Ten groups of five rats	16 weeks	Brown propolis, due to its antioxidant capacity, inactivated reactive nitrogen and oxygen species, which modified colon carcinogenesis in rats. Also, brown propolis prevented crypt cell clonal expansion.	[104]
Supercritical extract of green propolis	Artepillin C	BALB/c nude mice	100 mg/kg	Three groups of three mice	3 weeks	The complex of green propolis and γ cyclodextrin displayed antitumour activity in mice.	[100]

Figure 6. Visualization of the potential anticancer mechanisms of Brazilian propolis. Created with BioRender.com.

7. Use of Nanotechnology in Research on Brazilian Propolis

Nanotechnology is an interdisciplinary field of science concerned with the design, synthesis and application of structures of nanometric size (1–100 nm). Due to their unique properties, nanoparticles have found widespread applications in medicine, pharmaceutical industry and biomedical engineering. One of the most promising directions is the use of nanoparticles aimed at improving the bioavailability and efficacy of bioactive substances [17,105]. The most commonly used nanocarriers include lipid nanoparticles, liposomes, polymeric and metallic nanoparticles. Numerous studies support the application of different nanoparticles in combination with compounds of natural origin [106,107,108].

Brazilian propolis is a natural product rich in various bioactive compounds, such as artepilin C, flavonoids and phenolic acids, with proved anti-inflammatory, anticancer and antioxidant effects. However, their therapeutic efficacy is reduced by their low water solubility, chemical instability and limited bioavailability [109,110,111]. In this context, nanotechnology opens new prospects of improving the pharmacokinetic and biological properties of propolis, as well as increasing the stability, bioavailability and precision of drug delivery to target tissues and cells. Despite the increasing interest in nanotechnology applications regarding Brazilian propolis, the number of studies remain limited, as the complex chemical composition and properties suggest great potential still to be studied and explored for this purpose. Therefore, all the articles obtained are presented in Table 5 below.

Table 5. Biological effect of nanoparticles with Brazilian propolis extracts.

Type of Propolis	Nanoparticles	Dose	Disease Entity/Type of Cells	Activity/Mechanism/Effect	Ref.
Red Brazilian Propolis	Polymeric nanoparticles (nanocapsuled Brazilian red propolis extract NC-BRPE)	66–320 µg/mL	OVCAR-3 (ovarian cancer)	NC-BRPE enhanced the antitumour activity of propolis in ovarian cancer cells, both in 2D and 3D models.	[112]
Red Brazilian Propolis	Gold nanoparticles	200 μg/mL	Bladder cancer cells (T24) and prostate cancer cells (PC-3)	The cytotoxicity of nanoparticles with the hydroethanolic extract of Brazilian red propolis was induced by mechanisms associated with apoptosis.	[113]
Red Brazilian Propolis	Polymeric nanoparticles (nanocapsuled Brazilian red propolis extract NCBRPE)	2–1024 mg/L (2–1024 μg/mL)	OVCAR-3 cells	NCBRPE effectively limited the proliferation of cancer cells with long-term survival capacity. The antioxidant properties of NCBRPE were demonstrated by its ability to reduce ROS generation in neutrophils, thereby mitigating the oxidative stress that is commonly associated with tumorigenesis and immune suppression.	[19]
Red Brazilian Propolis	Gold nanoparticles (BRP-AuNPs)	BRP-AuNPs IC50 values were 27.32 µg/mL (RT4) and 53 µg/mL (PC3)	PC3 (prostate cancer) and RT4 (bladder cancer) cell lines	BRP-AuNPs exhibited a dose-dependent antitumour effect. In 3D viability assays, a superior antitumour effect of BRP-AuNPs was found when compared to free BRP extract.	[114]
Red Brazilian Propolis	Polymeric nanoparticles	-	Normal breast cells (MCF-10) Breast cancer cells (MCF-7)	Nanoparticle-encapsulated BRPE (NCBRPE) showed reduced toxicity to normal breast cells (MCF-10) but increased toxicity to breast cancer cells (MCF-7) compared to free BRPE, which indicates targeted therapeutic potential.	[115]

8. Conclusions and Future Prospects

With its distinct region-specific varieties and unique compositions of active compounds, Brazilian propolis demonstrates great therapeutic potential due to its anti-inflammatory and anti-tumour properties, which makes it a promising tool for adjuvant therapy. Its diverse bioactive components, including artepilin C, flavonoids, phenolic acids and benzophenones, allow for targeted action against inflammatory and cancerous processes. While numerous in vitro and in vivo studies have confirmed its efficacy, further clinical research is needed to better understand its mechanisms of action, determine optimal doses and select appropriate routes of administration. The production of Brazilian propolis is intertwined with the region’s unique ecosystem. The primary sources of raw material are endemic plants such as Baccharis dracunculifolia DC. (for green propolis) or Dalbergia ecastaphyllum (L.) Taub. (for red propolis). Bees collect resins from these plants and convert them into propolis, thus creating a substance rich in bioactive compounds. Given the increasing market demand and therapeutic interest, implementing sustainable extraction methods is essential to protect biodiversity while ensuring high product quality.

Future advancements in nanotechnology may enhance the bioavailability of propolis by encapsulating its active ingredients in biodegradable nanoparticles, which would improve both its stability and therapeutic efficacy. Additionally, biotechnology and tissue engineering could utilise propolis to develop biomaterials with anti-inflammatory properties, promoting tissue regeneration and supporting cancer treatment. Its potential role in immunotherapy also needs to be explored, particularly as an adjuvant to enhance the immune system’s response against chronic inflammation and cancer.

With the growing interest in natural products for medical applications, Brazilian propolis has the potential to become an important part of future therapeutic strategies. However, further research is necessary to fully understand its mechanisms, safety, and clinical efficacy. To conclude, it is worth emphasizing the need to develop sustainable production practices to protect ecosystems, standardization and quality control methods. It is necessary to ensure maximum therapeutic efficacy, strictly monitor the use of pesticides and possible replacement with organic formulations, as well as to provide refuges for wild pollinators, which indirectly affects the health and productivity of bees, including for propolis production.