Physicochemical Characteristics of Brazilian Green Propolis Evaluated During a Six-Year Period.

BACKGROUND: Propolis has been used as a natural health product mainly due to the presence of polyphenols, flavonoids, phenolic aldehydes, amino acids, vitamins and others bioactive constituents. To this natural substance are attributed different biological and pharmacological properties which are influenced by its chemical composition and organoleptic properties. The aim of this work was to evaluate the physicochemical properties and parameters of green propolis collected during a period of six years (2008-2013) in the state of Minas Gerais, located at the southeastern region of Brazil. METHODS: The methodology were in accordance with Brazilian legislation on the identity and quality standards of propolis. The evaluated parameters of hydroalcoholic from green propolis were total flavonoids, antioxidant activity - DPPH method, oxidation index, wax content, humidity and insoluble impurities. RESULTS: Propolis samples collected in different seasons during the years 2008 to 2013 presented mean values of total flavonoids (3.4 ± 0.11 mg/g), antioxidant activity DPPH (4.76 ± 0.16 µg/mL), oxidation index (3, 4 ± 0.33 seconds) and wax (15.14 ± 0.78% m/m), which are in accordance with Brazilian legislation. CONCLUSION: Green propolis did not show abrupt seasonal changes during the six years of investigation, and may be considered as an adequate functional ingredient.

Immunomodulatory properties of green propolis.

Propolis is a resinous material collected by honeybees from numerous plants and serves as a defense against intruders. Because of its relevant curative properties, it is now gaining popularity in health foods and in cosmetic products. Understanding the underlying molecular mechanisms of phytochemicals has become a good strategy in bioprospection for new anti-inflammatory compounds. The biological activity of propolis derives from its high levels of phenolic acids, while flavonoids are thought to account for the activity of propolis extracts. The comprehension of the relationship between propolis and the immune system has progressed in the last years, recent articles have provided important contributions to this investigation field. Studies have shown that propolis suppressed the "IL-6-induced phosphorylation of signal transducer and STAT3", an essential cytokine-activated transcription factor in Th17 development. Therefore, action mechanisms of "propolis on Th17 differentiation could be instrumental in controlling disturbed cytokine networks in inflammation, autoimmune diseases, and infections." The use of propolis has been proposed in some patents as: WO201363714; CN102885854, WO2013142936, US20130266521, and US20130129808, which are related to the treatment of dental diseases; adjuvant in anti-cancer treatment; in cosmetic products; as an anti-inflammatory agent and natural antibiotic. Although there are many publications regarding the propolis efficacy, its applicability to human health and mechanisms of action are not completely understood, creating opportunities for new studies.

Mucoadhesive propolis gel for prevention of radiation-induced oral mucositis.

The objective of this phase II study was to determine the effectiveness of a mucoadhesive propolis gel in the prevention of radiation-induced oral mucositis. Twenty-four patients who were selected to undergo radiation therapy for oral cancer were included in this open-label trial. They were advised to use a mucoadhesive gel containing propolis 5,0% w/v three times a day starting one day before the course of radiation therapy and concluding after 2 weeks of radiation therapy. A weekly follow-up for evaluation of food intake, pain and grading of mucositis was performed. In order to confirm the absence of Candida-related mucositis in patients who developed mucositis, it was performed exfoliative cytology of buccal mucosa, palate and tongue and the material for Candifast(®) Candida species identification. At the end of the study was made the compliance of patients, quality, appreciation and acceptance of product evaluation. Twenty patients did not develop mucositis, two patients developed grade 1 mucositis and two patients developed grade 2 mucositis. None of the patients discontinued food intake and no pain was observed during the study. Candidosis was not detected in any patient. Mucoadhesive propolis gel could be considered as a potential topical medication for preventing radiation-induced oral mucositis. However, comparative phase III study with larger number of patients should be done for confirmation of the efficacy of the product.

Efficacy of Brazilian propolis gel for the management of denture stomatitis: a pilot study.

Denture stomatitis presents as a chronic disease in denture-bearing patients, especially under maxillary prosthesis. Despite the existence of a great number of antifungal agents, treatment failure is observed frequently. Propolis, a natural bee product, possesses well-documented antifungal and anti-inflammatory activities. The purpose of this study was to evaluate the clinical efficacy of a new Brazilian propolis gel formulation in patients diagnosed with denture stomatitis. Thirty complete-denture wearers with denture stomatitis were enrolled in this pilot study. At baseline, clinical evaluation was performed by a single clinician and instructions for denture hygiene were provided. Fifteen patients received Daktarin (Miconazole gel) and 15 received Brazilian propolis gel. All patients were recommended to apply the product four times a day during one week. Clinical evaluation was repeated by the same clinician after treatment. All patients treated with Brazilian propolis gel and Daktarin had complete clinical remission of palatal edema and erythema. This new Brazilian propolis gel formulation had efficacy comparable to Daktarin and could be an alternative topical choice for the treatment of denture stomatitis.

Evaluation of the analgesic and anti-inflammatory effects of a Brazilian green propolis.

Phamacological activities of a standard ethanol extract G1 from Brazilian green propolis, typified as BRP1, was evaluated in mouse models of pain and inflammation. Intraperitoneal injection ( I. P.) of G1 inhibited acetic acid-induced abdominal constrictions with an ID (50) = 0.75 +/- 0.05 mg/kg, and in the formalin test the ID (50) values were 0.85 +/- 0.07 mg/kg and 13.88 +/- 1.12 mg/kg, respectively, for the neurogenic and inflammatory phases. The extract was ineffective when assessed in the hot-plate assay. In serotonin-induced paw edema, G1 led to a maximal inhibition (MI) of 51.6 % after 120 min when administered I. P. and of 36 % after 15 min by the oral route ( O. R.). When the inflammatory agent was complete Freund's adjuvant, inhibition of paw edema was also observed after administration of the extract by both routes. In the capsaicin-induced ear edema the ID (50) values were 1.09 +/- 0.08 mg/kg ( I. P.) and 10.00 +/- 0.90 mg/kg ( O. R.). In the acute carrageenan-induced inflammatory reaction induced by carrageenan, G1 reduced the number of neutrophils in the peritoneal cavity with IC (50) values of 0.72 +/- 0.08 mg/kg and 4.17 +/- 0.50 mg/kg, by I. P. or O. R. administration, with a preferential migration of polymorphonuclear neutrophils. IN VITRO, G1 decreased nitric oxide production in LPS-stimulated RAW 264.7 cells (IC (50) = 41.60 microg/mL), and also the luciferase activity in TNF-alpha-stimulated HEK 293 cells transfected with NF-kappaB-luciferase reporter gene driven by the nuclear factor kappaB (NF-kappaB) (IC (50) = 200 microg/mL). This extract, which at low concentrations induces anti-inflammatory and analgesic effects in mouse models, presents a high content of flavonoids, known to inhibit inducible NOS (iNOS) activity. These data taken together led us to reinforce the hypothesis in the literature that the anti-inflammatory effect of propolis may be a due to inhibition of iNOS gene expression, through interference with NF-kappaB sites in the iNOS promoter.