Brazilian Propolis Research Articles

Metabolite profiling, antioxidant and antibacterial activities of Brazilian propolis: Use of correlation and multivariate analyses to identify potential bioactive compounds

The production of propolis by honeybees results from a selective collection of exudates from various plant species and present many potentialities in the pharmaceutical industry. The objective of this study was to investigate the chemical profile of Brazilian propolis, as well as their in vitro antioxidant and antibacterial activities. Gas chromatography–mass spectrometry was applied for chemical profiling of propolis extracts. Total phenolic compounds were quantified by Folin-Ciocalteu and antioxidant properties were assessed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Antibacterial activity was assessed against Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus. Correlation and multivariate statistical analysis were used to identify potential bioactive compounds in the extracts. Twenty-nine metabolites were identified along with 34 other metabolites that were classified into the following classes: triterpenoids (12), acetyltriterpenoids (3), sesquiterpenes (6), steroids (4), and hydrocarbons (9). The antioxidant capacity (IC50) ranged from 21.50 to 78.77μg/mL, whereas the content of total phenolic compounds ranged from 31.88 to 204.30mg GAE/g of dry weight. Total phenolic compounds and methyl retinoate showed a positive correlation with the antioxidant capacity, whereas tetradecanal, γ-palmitolactone and ethyl hydrocinnamate showed a negative correlation. Different sets of metabolites are shown to correlate with the antibacterial activity of the extracts, which is largely dependent on the type of microorganism. This innovative approach allowed us to identify likely bioactive compounds in the extracts, although the mechanism(s) underlying antibacterial activity encompass a complex trait, which might involve synergistic effects.

Propolis restored adiponectin level in type 2 diabetes through PPARγ activation

Adipose tissue regulates insulin sensitivity via the circulating adipocytokines, leptin, resistin and adiponectin. Hypoadiponectinemia contributes to the development of obesity and related disorders such as diabetes, hyperlipidemia, and cardiovascular diseases. In this study, we investigated the effects of Brazilian propolis on adiponectin levels in type 2 diabetes mellitus (T2DM), the mechanism of signaling pathway was explored as well. T2DM was induced in male Wistar rats using high fat diet and low dose of streptozotocin (STZ, 35 mg/kg, i.p.). Propolis was administered by oral tubes. Peroxisome proliferator activated receptor gamma (PPARγ) levels in sub abdominal adipose tissue, serum levels of adiponectin, tumor necrosis factor-α (TNF-α) and insulin were detected by Enzyme Linked Immunosorbent Assay (ELISA). Malondialdehyde (MDA) and reduced glutathione (GSH) in sub abdominal adipose tissue, fasting plasma glucose, plasma triglycerides and total cholesterol levels were measured by colorimetric method. Results showed that Brazilian propolis ameliorated hypoadiponectinemia in T2DM rats and relieved high glucose-induced adiponectin decrease. The signaling pathway analysis indicated that PPARγ regulation was involved. In conclusion, Brazilian propolis could have beneficial effect in T2DM by increasing tissue PPARγ levels, restoring serum adiponectin levels, enhancing insulin sensitivity and subsequently, attenuating elevated glucose level.

Chemopreventive Effect of Brazilian Red Propolis on the Oral Carcinogenesis in Rodent Model

Chemopreventive Effect of Brazilian Red Propolis on the Oral Carcinogenesis in Rodent Model

Brazilian Propolis Production by Africanized Bees (Apis mellifera)

Propolis is a substance produced by bees from plant sources located in the vicinity of the bee hives and it has a wide spectrum of biological properties. Brazilian propolis stands out due to its unique characteristics. In the 1990s, some Brazilian beekeepers started specializing in propolis production due to growing commercial demand for this product. In the districts where propolis production is plentiful, propolis harvests have become the main product and honey is not even harvested. Nowadays, harvesting techniques have improved and productivity increased substantially. Here, we report on characteristics of propolis and the evolution of propolis harvest in Brazil.

Chemical Composition of the Same Brazilian Propolis Sample Analyzed in 1997 and in 2012: No Freezing Effect

The same propolis sample that was analyzed by GC-MS in 1997 and 2012 was examined again after being frozen for 15 years. No qualitative changes were seen in its composition; artepilin C, prenyl-p-coumaric acid, dihydrocinnamic acid, caffeic acid were the major compounds.

Comparison of Antimicrobial Efficacy of Brazilian Propolis With Chlorhexidine and Sodium Fluoride Against Common Oral Pathogens: An In Vitro Study

Background: Oral diseases continue to represent a major health problem worldwide. Various bacteria and fungi are found to be the possible pathogens responsible for the oral disease. Objectives: The present in vitro study was conducted to compare the antimicrobial efficacy of mouthrinse (MR) prepared from Brazilian propolis with that of two commercially available MR, Hexidine (chlorhexidine mouthrinse) (CHX), S-Flo (0.2% sodium fluoride) against common oral pathogens i.e. Streptococcus mutans, Candida albicans and Escherichia coli. Materials and Methods: The antimicrobial efficacy of three MR was measured against freeze-dried culture of S. mutans (MTCC 890), E. coli (MTCC 44) and C. albicans (MTCC 1637).The antimicrobial activity was determined by the agar well diffusion method and the zone of inhibition produced by the mouthwashes against the test organisms was measured. The data were analyzed using SPSS software, version 20 and the one-way ANOVA test was used to compare in vitro antimicrobial activity of various MR. Results: The antimicrobial efficacy of Hexidine against S. mutans and E. coli was higher compared to that of C. albicans. The Brazilian Propolis (P) MR showed antimicrobial action against S. mutans and C. albicans. The antimicrobial efficacy of P against C. albicans was higher compared to that of CHX. The S-Flo MR (0.2% sodium fluoride) and the negative control group did not show any zone of inhibition against all three test stains. Conclusions: The results of the present study indicate that Brazilian Propolis demonstrated in vitro anti-microbial efficacy against S. mutans and C. albicans.

Nitric oxide and Brazilian propolis combined accelerates tissue repair by modulating cell migration, cytokine production and collagen deposition in experimental leishmaniasis.

The fact that drugs currently used in the treatment of Leishmania are highly toxic and associated with acquired resistance has promoted the search for new therapies for treating American tegumentary leishmaniasis (ATL). In this study, BALB/c mice were injected in the hind paw with Leishmania (Leishmania) amazonensis and subsequently treated with a combination of nitric oxide (NO) donor (cis-[Ru(bpy) 2imN(NO)](PF6)3) (Ru-NO), given by intraperitoneal injection, and oral Brazilian propolis for 30 days. Ru-NO reached the center of the lesion and increased the NO level in the injured hind paw without lesion exacerbation. Histological and immunological parameters of chronic inflammation showed that this combined treatment increased the efficacy of macrophages, determined by the decrease in the number of parasitized cells, leading to reduced expression of proinflammatory and tissue damage markers. In addition, these drugs in combination fostered wound healing, enhanced the number of fibroblasts, pro-healing cytokines and induced collagen synthesis at the lesion site. Overall, our findings suggest that the combination of the NO donor Ru-NO and Brazilian propolis alleviates experimental ATL lesions, highlighting a new therapeutic option that can be considered for further in vivo investigations as a candidate for the treatment of cutaneous leishmaniasis.

Acute and sub-acute oral toxicity of Brazilian red propolis in rats

Ethnopharmacological relevancePropolis is a bee product widely used in folk medicine due to its numerous pharmacological properties. However, samples from different regions can differ in chemical composition, effectiveness, and side effects. Despite the widespread use of Brazilian red propolis, which is an isoflavone-rich variety, its toxicity has not been carefully studied. Aims of the studyTo assess the acute and sub-acute toxicity of the hydroethanolic extract of red propolis (HERP) administered orally to rats. Materials and methodsHERP for the acute (300mg/kg) and sub-acute (10, 100 and 200mg/kg) toxicity studies was administered orally to rats according to OECD Guidelines 420 and 407, respectively. Clinical signs were identified, and hematological and biochemical analyses were performed. Water and food uptake as well as body and organ weights of animals were recorded. Results and conclusionsThe acute study revealed no lethal effects at 300mg/kg of HERP, but toxic signs were observed, as HERP had an LD50 of more than 300mg/kg, indicating a warning. The most toxic signals in sub-acute studies were observed in males at a dose of 200mg/kg HERP. These results suggest estrogen-like activity, possibly from the isoflavones in HERP.

Antimicrobial Activity of Propolis Extracts against Skin Pathogen

Propolis extracts from Korea and Brazil were investigated for their antibacterial and antifungal activities against skin pathogen. For this, we used 80% ethanol extracts of propolis from Korea (KPEE) and Brazil (BPEE). Minimal inhibitory concentration (MIC) for the strains tested was determined using the method of broth dilution with the KPEE and BPEE in serial concentration, respectively. The antibacterial activity of KPEE showed MIC of 0.25μg/ml for Bacillus subtilis and Escherichia coli; 0.5μg/ml for Staphylococcus aureus; 1.0μg/ml for Propionibacterium acnes. However, the MIC of BPEE for B. subtilis, S. aureus, P. acnes, and E. coli was 1.0, 0.5, 4.0, and 0.5μg/ml. The antifungal activity of KPEE using agar diffusion test was 24.34±0.5, 19.19±1.0 and 26.64±1.0 of the inhibitory zone for Trichophyton tonsurans, T. mentagrophytes and T. rubrum. The inhibitory zone of BPEE was 11.48±0.3, 11.0±0.5 and 13.11±0.5 for T. tonsurans, T. mentagrophytes and T. rubrum. All tested skin pathogens were more susceptible to the KPEE than BPEE. It seems that the Korean propolis has antimicrobial activity more than Brazilian propolis.

Behavioral changes and feathering score in heat stressed broiler chickens fed diets containing different levels of propolis

This experiment was conducted to evaluate the effects of dietary supplementation of green Brazilian propolis on behavioral patterns and feather condition of heat stressed broiler chickens. Five hundred and four (504) male Ross 708 broiler chicks at 15-day old were randomly allotted to six dietary treatments containing 0 (control), 100, 250, 500, 1000 and 3000mgkg−1 propolis, respectively. Each treatment consisted of four replicates of 21 birds each. Heat stress at 32°C was applied daily from 08:00 am to 17:00 pm from day 15–42. Twelve birds per treatment were randomly taken and marked with livestock color for behavioral observation. Treatment effects on behavioral patterns were recorded using direct observation instantaneous scan sampling technique. At the end of the experiment (42 days of age) the three birds used for behavioral observation were feather scored (from 1 to 5); while all birds (504) were individually scanned for primary feather abnormalities. The results indicated that the effects of using propolis as a feed additive for broilers reduced heat stress behavior, especially dietary treatment with 250 or 3000mgkg−1 propolis, by increasing bird walking activities and reducing panting behaviors (P<0.05, respectively). Moreover, 250mgkg−1 propolis (P<0.05) increased standing behavior also. Walking activities was also increased in the birds fed with 100mgkg−1 propolis (P<0.05). There were no significant (P>0.05) treatment effects on sitting, preening, feeding, drinking, wing elevations and feather pecking activities. Propolis at current doses did not significantly (P>0.05) improve feather scoring, but reduced (P=0.048) abnormal shape of primary feathers. The current results support that propolis treatment may be considered as a protective management practice in broiler chickens to alleviate the negative effects of heat stress, but further investigations may requested to determine the best type, dose, time and duration of its administration.

PVA hydrogels loaded with a Brazilian propolis for burn wound healing applications

ABSTRACTPVA hydrogels offer many suitable characteristics for burn wound dressings. However, unmodified PVA gels do not act against infection. Propolis is a natural antimicrobial agent suitable for incorporation into PVA gels. PVA–propolis gels were produced by freeze–thawing method, and their microstructure, mechanical, and swelling properties (in standard PBS and a PBS‐based solution with pH 4.0) were characterized. The propolis release profiles and the gel's antibacterial and cytotoxicity properties were also investigated. The presence of propolis in the gels interfered with the PVA crystallization profile and with the mechanical properties. All samples swelled at least 400% in both media. The propolis was mostly released to the media in the first day of immersion. PVA–propolis gels with concentrations of 15% propolis or more were active against the gram‐positive bacterium Staphylococcus aureus, which is associated with initial colonization of the wound. All PVA–propolis samples acted as barriers to microbial penetration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42129.

Effect of Brazilian green propolis in patients with type 2 diabetes: A double-blind randomized placebo-controlled study

Propolis contains a variety of chemical compounds, including polyphenols, flavonoids, phenolic aldehydes, amino acids and vitamins, and presents numerous biological and pharmacological properties. The aim of the present study was to evaluate the effect of propolis on blood examination data in patients with type 2 diabetes. In the double-blind, 8-week randomized controlled study, 80 patients with type 2 diabetes were enrolled. Patients were randomly assigned to receive Brazilian green propolis (226.8 mg/day for 8 weeks) (n=41) or the placebo (n=39). The primary endpoint was to detect changes in blood examination data associated with metabolic disorders in patients suffering from diabetes mellitus, including the homeostasis model assessment of insulin resistance (HOMA-IR), uric acid and estimated glomerular filtration rate (eGFR) from baseline to the end of this study. The value of HOMA-IR was not significantly changed by the 8-week administration of propolis or placebo from the baseline data. Values of blood uric acid and eGFR in patients taking the placebo became worse at 8 weeks compared to the baseline, whereas this did not occur in patients consuming Brazilian green propolis. However, HOMA-IR was not improved by propolis intake. A randomized, controlled 8-week trial suggests that Brazilian green propolis (226.8 mg/day) prevents patients with type 2 diabetes from developing worse blood uric acid and eGFR.

Inhibition of DMBA-induced Oral Squamous Cells Carcinoma Growth by Brazilian Red Propolis in Rodent Model.

We investigated the effect of oral administration of hydroalcoholic extract of Brazilian red propolis (HERP) on DMBA-induced oral squamous cell carcinomas (OSCC) in rodents. The chemical components of the HERP were assessed by high-performance liquid chromatography (HPLC). Carcinogenesis was topically induced in the lower lip of 25 rats using 9,10-dimethyl-1,2-benzanthracene (DMBA); the tumour was treated with saline (TUM1) and Tween 80 (TUM2) as well as HERP at 10, 50 and 100 mg/kg (HERP10, HERP50 and HERP100, respectively) for 20 weeks. Topical application of saline and oral administration of 100 mg/kg HERP was used in five rats as a control group (CTR). After 26 weeks, the histological malignancy grading and immunohistochemical expression of Ki-67 and p16(INK4A) were assessed in the tumours/tissue samples. The compounds identified were propyl gallate, daidzein, catechin, epicatechin, formononetin and biochanin A. Formononetin, daidzein and biochanin A showed concentration of 23.29, 0.38 and 0.67 mg/g of HERP, respectively. HERP at doses of 50 and 100 mg/kg inhibited 40% of OSCC growth and promoted a 3-week delay in development of clinically detectable tumours. Epithelial dysplasia was observed in all samples with no clinical tumour, except in CTR. No significant difference in the immunoexpression of Ki-67 and p16(INK4A) was observed between HERP-treated and saline/Tween 80-treated groups (p > 0.05). Our results suggest that HERP exerts chemopreventive activity on the progression of DMBA-induced epithelial dysplasia to OSCC in an experimental model of labial carcinogenesis; however, this effect is not associated with Ki-67 and p16(INK4A) immunoexpression.

Effect of Brazilian Red Propolis on the Development and Immunohistochemical Expression of Ki-67 and p16INK4A in DMBA-Induced Oral Squamous Cell Carcinomas

Effect of Brazilian Red Propolis on the Development and Immunohistochemical Expression of Ki-67 and p16INK4A in DMBA-Induced Oral Squamous Cell Carcinomas

In vitro evaluation of the acquisition of resistance, antifungal activity and synergism of Brazilian red propolis with antifungal drugs on Candida spp.

To evaluate the ability of Candida parapsilosis and Candida glabrata to develop phenotypic resistance to a benzophenone enriched fraction obtained from Brazilian red propolis (BZP-BRP) as compared to fluconazole (FLC). To investigate possible synergy between BZP-BRP and FLC and anidulafungin (AND). To analyse the development of resistance, isolates susceptible to these antifungals were cultured in increasing concentrations of FLC and BZP-BRP. The increase in FLC minimum inhibitory concentration for all isolates was evident and the majority developed resistance, whereas none isolated became less susceptible to BZP-BRP. Synergism was investigated by checkerboard method. BZP-BRP demonstrated synergy with FLC and indifference with AND for most isolates. In conclusion, the synergism observed with FLC suggests that BZP-BRP could be a possible therapeutic strategy for the treatment of infections related to FLC-resistant Candida sp. The indiscriminate use of antifungals results in the emergence of drug-resistant strains among previously susceptible populations. BZP-BRP can become an alternative for the treatment of persistent infections caused by Candida sp.

Brazilian red propolis attenuates hypertension and renal damage in 5/6 renal ablation model.

The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD) is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene) as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP), in the 5/6 renal ablation model (Nx). Adult male Wistar rats underwent Nx and were divided into untreated (Nx) and RP-treated (Nx+RP) groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection.

Composition of the volatile fraction of a sample of Brazilian green propolic and its phytotoxic activity.

Propolis is a resinous material produced by honeybees, containing mainly beeswax and plant material. Despite the wide spectrum of biological activity of propolis, to our knowledge no studies have been carried out about phytotoxic properties of Brazilian propolis and its constituents. The aims of this study were to analyze the chemical composition and to evaluate the phytotoxic activity of the volatile fraction of a sample of Brazilian green propolis. Main constituents are the phenylpropanoid 3-prenylcinnamic acid allyl ester (26.3%) and the sesquiterpene spathulenol (23.4%). Several other sesquiterpenes and phenylpropanoids, in addition to linalool and α-terpineol (monoterpenes), were also detected. The activity of solutions of the volatile fraction at 1.0, 0.5 and 0.1% was tested on lettuce seeds and seedlings. The solution at 1% inhibited completely the seed germination and solutions at 0.1 and 0.5% reduced the germination rate index. The solution at 0.5% reduced the growth of the hypocotyl-radicle axis and the development of the cotyledon leaf. The chemical composition of the volatile fraction of this Brazilian green propolis is different from those previously described, and these results may contribute to a better understanding about the chemical variations in propolis. The volatile fraction of Brazilian green propolis influences both germination of seed lettuce and the growth of its seedlings, showing an phytotoxic potential.

Anti-inflammatory property of propolis.

Dear Editor-in-Chief, The recent article by Weina Gao and colleagues, on July issue of this Journal, showed that Brazilian green propolis have a positive effect on innate and adaptive immunity in aged mice.(1) This role should be mainly attributed to flavonoids contained in propolis.(2) The Authors reported that Brazilian propolis had 189.12 mg/g total polyphenols, 98.46 mg/g flavonoids, 1.95 mg/g cinnamic acid and 23 mg/g artepillin-C.(1) Yet, the participation of any single molecule to the reported evidence in aged animals might have involved different spectra of activity and different molecular targets in promoting the beneficial action observed by the Authors.(1) Artepillin C, namely (E)-3-[4-hydroxy-3,5-bis(3-methylbut-2-enyl)phenyl]prop-2-enoic acid, is one of the major component in Brazilian propolis and recent reports have stressed its ability to block the serine/theonine protein kinase known as PAK-1.(3) PAK proteins are critical effectors that link the Rho family of GTPases to the cytoskeleton reorganization and nuclear signaling; These proteins serve as targets for the small GTP binding proteins Cdc42 and Rac and have been implicated in a wide range of biological activities, for example PAK1 regulates cell motility and morphology, furthermore the role of Cdc42 GTPases activating protein in aging has been recently reported.(4) The involvement of PAK1 in inflammatory and neuro-degenerative disorders suggests that this molecules is targeted in aging mechanism. Few natural PAK1-blockers such as rosmarinic acid, curcumin and caffeic acid extend the lifespan of the nematode Caenorhabditis elegans or fruit flies.(5) PAK1 promotes reproduction, whereas it inactivates HSP16.2 gene and shortens lifespan, as do also PI-3 kinase (AGE-1), mTOR, and insulin-like signalling (ILS) (Daf-2) in this nematode.(5) It is arguable that caffeic acid and particularly artepillin-C play a role in slowing aging cellular mechanism and synergistically exert an anti-inflammatory action with propolis flavonoids.(4) This suggestive speculation may appear contradictory when data from serum in aged mice, showing a marked increase in inflammatory cytokines on increasing Brazilian propolis assumption, are considered.(1) The Authors concluded that this evidence assessed the improvement in inflammatory response caused by propolis in aged mice.(1) This circumstance addresses the positive role exhibited by nature-derived phytochemicals on stressed, dysregulated, aged or infected (inflamed) cells. Therefore, while a wide literature exists reporting the anti-inflammatory role of flavonoids,(6) many data from clinics should suggest a pro-inflammatory role exerted by polyphenols in restoring health, prevent cancer onset and degenerative disorders.(7) Fundamentally, as like as in propolis, the most proper idea about the activity of nature-derived polyphenols and phenolic substances, should deal with the concept of immune modulation, depending on the cell nature and homeostatic balance, not merely an improvement given by inhibition or promotion coming from the molecular nature of these molecules. Propolis is widely used as an anti-inflammatory raw substance, expecially during allergy and airway inflammatory disorders. The interesting paper by Weina Gao et al., would suggest that in elderly people Brazilian propolis may ensure a health promoting action by activating the immune response.(1) This is formally true but literature reports many data with potentially misleading evidence about. A combination therapy (anti-inflammatory drugs plus propolis) in aged adults showed encouraging results(8) and, moreover, due to yet contradictory results from clinics,(9) respect to in vitro and animal evidence,(1,10) a more cautious, critical and less enthusiastic debate about this substance has to be taken into account in the next future. Looking forward to a kind reply from yours.

Propolis as an Anti-allergy Based on Decrease in Total Eosinophil Count in Rat Models

Background : Propolis is a natural herb derived from plant resins by bees. Propolis contains flavonoids that act as anti-allergy. The composition of flavonoids in propolis varies according to each region like Brazilian, Chinese, Malaysian and Indonesian propolis due to differences in medicinal plants in that area. The aim of this study is to determine the effect of propolis as an anti-allergy and to determine which is the most effective among propolis of Brazilian, Malaysian and Indonesian origin. Methods : An experimental study was performed on 28 Wistar male rats divided into four groups, Brazilian, Malaysian, Indonesian propolis and a negative control group. The used parameter was decreased in total eosinophil count in ovalbumin induced allergy in rats. Propolis or aquadest as control were given orally 0.25ml once daily. Results : All three groups of propolis showed statistically significant results (p<0.05), in decreasing eosinophil count. However, Malaysian and Brazilian propolis showed much more significant effects compared to that of Indonesian propolis. This could be due to the difference in composition and concentration of flavonoids in Indonesian propolis compared to the Brazilian and Malaysian propolis. Conclusion : Propolis has a significant effect as an anti-allergy. Malaysian and Brazilian propolis are more effective as an anti-allergy compare to Indonesian propolis. Propolis can thus be used as an alternative treatment for allergy. [AMJ.2015;2(1):208–12]

Brazilian propolis extract increases leptin expression in mouse adipocytes.

We investigated the anti-obesity effects of Brazilian green propolis ethanol extract using a mouse model of obesity. Repeated intraperitoneal injection of propolis (100 mg/kg twice a week) caused feeding suppression in C57BL/6 mice, whereas this treatment had negligible effects on C57BL/6 ob/ob mice. Since C57BL/6 ob/ob mice have a missense mutation in the Lep gene, leptin is likely to contribute to the propolis-induced feeding suppression. We found that propolis treatment indeed clearly increased leptin mRNA production in the visceral adipose tissues. Moreover, propolis extract directly elevated leptin expression in differentiated 3T3-L1 adipocytes. Artepillin C, an important organic compound found in Brazilian green propolis, failed to induce leptin mRNA in 3T3-L1 cells. Compounds other than artepillin C in Brazilian propolis must thus cause leptin induction in adipocytes, possibly resulting in the suppression of feeding and obesity.