Immunomodulatory Effect of Propolis on Foxp3 Gene Expression in Human Peripheral Blood Mononuclear Cells Stimulated in vitro with Pseudomonas Aeruginosa Ag

Immune balance during infection is critical for both supporting the defense of the immune system of the body and preventing an overly aggressive immune response. Foxp3, a transcription factor of regulatory T cells, plays a critical role in balancing the immune system of the body. Propolis has been shown to affect Foxp3 expression. This study aimed to verify the effect of propolis extracts on in vitro Foxp3 gene expression in peripheral blood mononuclear cells (PBMCs) stimulated with Pseudomonas aeruginosa Ag. In this study, a total of 20 apparently healthy volunteers were included, with 10 males and 10 females within the age range of 20-40 years old. Five ml of blood were drawn from each participant to assess Foxp3 gene expression in PBMCs using density gradient lymphoprep and stimulated with P.aeruginosa lipopolysaccharide (LPS) in vitro. The samples were divided into four distinct groups as follows: LPS stimulated PBMCs, ethanol-extracted propolis (EEP) + LPS stimulated PBMCs, and water-extracted propolis (WEP) + LPS stimulated PBMCs and PBMCs as the control group. The Foxp3 gene expression level was estimated in all four groups following a period of 48 h of cultivation by real-time polymerase chain reaction technique using SYBR green dye. Results of the study indicated that propolis had a great effect on the mRNA Foxp3 expression. Both EEP and WEP had immunomodulatory effects through the Foxp3 mRNA expression, both the EEP and WEP could significantly inhibit Foxp3 mRNA gene expression by human PBMCs after stimulation with pseudomonas Ag in vitro. Propolis exhibited an immunoregulatory effect which was the same with ethanol and water extracts on Foxp3 mRNA gene expression.

The use of propolis as vaccine's adjuvant

The success of many vaccines relies on their association with selected adjuvants in order to increase their immunogenicity and ensure long-term protection. All available adjuvants have adverse effects due to their toxicity and reactogenicity. Pre-clinical in vivo investigations can identify new natural products for further applications. Several studies have confirmed the different medicinal benefits of propolis. However the studies that addressed its use as a potent, safe, vaccine adjuvant were limited to specific countries and languages, primarily Chinese. Those studies introduced the use of different extracts and formulations of propolis as adjuvants for bacterial, viral, and parasitic vaccines. This comprehensive up-to-date review categorizes, documents, and discusses those trials in a clear chronological manner.

Protective effect of propolis against oxidative stress and immunosuppression induced by oxytetracycline in rainbow trout (Oncorhynchus mykiss, W.)

The aim of this study was to investigate the effects of propolis on oxytetracycline (OTC)-induced oxidative stress and immunosuppression in fish. OTC (100 mg per kg⁻¹ body weight) was orally administered to fish for 14 days. A significant elevation in the level of malondialdehyde, as an index of lipid peroxidation, and reductions in antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and low molecular weight antioxidant (reduced glutathione) levels were observed in the blood, liver, kidney, spleen, and heart tissues of OTC-treated fish. OTC also had a suppressive effect on specific and non-specific immune system parameters, such as leucocyte counts, oxidative radical production (nitrobluetetrazolium activity), total plasma protein and immunoglobulin levels, and phagocytic activity. Pre-treatment, post-treatment, and simultaneous treatment with propolis (50 mg per kg⁻¹ body weight, orally) attenuated the OTC-induced oxidative stress by significantly decreasing the levels of malondialdehyde in tissues. In addition, propolis significantly increased the level of reduced glutathione and the catalase, glutathione peroxidase, and superoxide dismutase activities. Upon the administration of propolis, the suppressed immune system parameters were significantly increased in fish treated with OTC. The present results suggest that pre-treatment, post-treatment, and simultaneous administration of propolis might alleviate OTC-induced oxidative stress and immunosuppression.

Propolis specimens from different locations of central Italy: chemical profiling and gas chromatography-mass spectrometry (GC-MS) quantitative analysis of the allergenic esters benzyl cinnamate and benzyl salicylate

Propolis is a beehive product popular in natural medicine thanks to its noteworthy properties. Propolis is non-toxic but is responsible for allergic reactions in sensitive individuals. In this paper, we propose a new gas chromatography-mass spectrometry (GC-MS) analytical methodology for the quantitative analysis of two allergenic esters in propolis specimens, benzyl salicylate and benzyl cinnamate, and test it on specimens from different locations of central Italy. We also present the results obtained in the chemical characterization of the same specimens. The characterization showed that the resin fractions of all of the specimens are of poplar origin.

Contact allergy to propolis in beekeepers

BACKGROUND

Allergy to propolis seems to be rare and little is known about it.

OBJECTIVE

The aim of the study was to survey a subset of affected beekeepers to determine aspects such as time of onset of disease, comorbidity, and possible methods of prevention.

METHODS

With the help of two German journals for beekeepers we contacted 41 beekeepers with propolis allergy. They were sent a questionnaire which assessed several aspects of the disease and was based on the current literature.

RESULTS

70.7% returned our questionnaire and had clear signs of propolis allergy with positive testing by their local allergologists. They reported that allergy had developed after an average of 9.5 years beekeeping. We also found a high prevalence of other allergies (72.4%). Interestingly, there were also systemic reactions to propolis in some beekeepers but not necessarily when using propolis as a medication against other diseases. Beekeepers believed that solvents used to clean the hands could play a role in the development of the disease.

CONCLUSION

This study provides new insights into allergy to propolis. The hypothesis that solvents used to clean the hands could play a role in the development of the disease should be addressed in future studies.

Adjuvant effect of green propolis on humoral immune response of bovines immunized with bovine herpesvirus type 5

Despite recent technological advances in vaccine production, most vaccines depend on the association with adjuvant substances. In this study, propolis, which has been attracting the attention of researchers due to its bioactive properties, was evaluated as an immunological adjuvant. The association of 40mg/dose of an ethanolic extract of green propolis with an inactivated oil vaccine against bovine herpesvirus type 5 (BoHV-5), resulted in a significant increase (P<0.01) in the neutralizing antibody levels, comparing to the bovines that received the same vaccine without propolis. Besides, propolis increased the percentage of animals with high antibody titers (above 32). Phenolic compounds such as artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) and the derivatives of cinnamic acid besides other flavonoid substances were abundant in the propolis extract used, and they could be the main substances with adjuvant action. The effect of the green propolis extract on the humoral immune response can be exploited in the development of new vaccines.

Autosensitization dermatitis associated with propolis-induced allergic contact dermatitis

Propolis is a beehive product known for its anti-inflammatory properties. With its growing use, propolis-induced contact dermatitis is increasing. While the dermatitis mostly occurs on areas directly exposed to propolis, our case presented an additional eczema at a site distant from the primary propolis-induced contact dermatitis twice in the same individual. We diagnosed it as an autosensitization dermatitis associated with propolis-induced allergic contact dermatitis.

Allergic contact dermatitis from propolis

Propolis is commonly used in cosmetic and medicinal preparations because of its antiseptic, antiinflammatory, and anesthetic properties. Its therapeutic qualities have been well documented. However, 1.2 to 6.6% of patients who are patch-tested for dermatitis are sensitive to propolis. The main allergens are 3-methyl-2-butenyl caffeate and phenylethyl caffeate. Benzyl salicylate and benzyl cinnamate are less frequent sensitizers. Propolis is found in a number of "natural" products, including lip balms, cosmetics, lotions and ointments, shampoos, conditioners, and toothpastes. Dermatologists should consider patch testing with propolis in users of such remedies.

Psoriasiform contact dermatitis due to propolis in a beekeeper

BACKGROUND

More than 250 cases of allergic contact dermatitis due to propolis have been described. A few of these occurred in beekeepers.

OBJECTIVE

To describe a case of psoriasiform dermatitis caused by propolis in a beekeeper who thought that his lesions were related to honeybee stings.

METHODS

A 45-year-old beekeeper experienced hand dermatitis for the past 5 years. He believed that the lesions occurred and worsened when he was stung by honeybees. He was prescribed topical corticosteroids several times, but because he was stung frequently, the drugs never helped control the lesions. In the past few years, he frequently had contact with propolis during honey collection, but he denied the role of propolis because he was wearing gloves while handling the beehives. For diagnostic evaluation, skin biopsy, skin prick tests (SPTs), identification of specific IgE antibodies, and atopic patch tests were performed.

RESULTS

Skin biopsy showed psoriasiform contact dermatitis. Results of SPTs to honeybee and serum specific IgE for Apis mellifera remained negative. Results of the atopic patch test performed using A mellifera SPT material were also negative in the first 20 minutes and on the second and third days. However, propolis showed a positive erythematopapular reaction on day 2. The patient never again worked as a beekeeper, and neither did he, as far as he knew, use any medical or cosmetic products that contained propolis. His hand lesions improved almost completely.

CONCLUSION

Dermatitis due to propolis should never be disregarded in beekeepers, and every effort should be put forth to make a correct diagnosis and to convince the patients of the cause.

Effect of propolis, some isolated compounds and its source plant on antibody production

Propolis is a beehive product with a very complex chemical composition, widely used in folk medicine because of its several therapeutic activities. Its biological properties and chemical composition may vary according to the geographic location and to the different plant sources. The possible mechanism of action of propolis as well as of its active compounds has been the subject of researchers in recent years. In this work, first we reported the results of our study on the seasonal effect of the immunomodulatory action of propolis on antibody production in bovine serum albumin (BSA)-immunized rats. Then, we compared the effect of Brazilian and Bulgarian propolis, some isolated compounds and Baccharis extract on anti-BSA antibody levels. Based on the results, we conclude that propolis stimulates antibody production, independently of the season and geographic origin. Caffeic acid, quercetin and Baccharis extract had no effect on antibody production, although the importance of isolated compounds is well reported in other biological assays. Propolis action is a consequence of plant-derived products with synergic effects, while isolated compounds or extracts from its plant sources had no effect in this assay.

The effect of herbal remedies on the production of human inflammatory and anti-inflammatory cytokines

BACKGROUND

Some herbal remedies are sold as food additives and are believed to have immune-enhancing properties.

OBJECTIVES

To study the effect of five herbal remedies--Sambucol Black Elderberry Extract, Sambucol Active Defense Formula and Sambucol for Kids (with known antiviral properties), Protec and Chizukit N (containing propolis and Echinacea, claimed to be immune enhancers)--on the production of cytokines, one of the main components of the immune system.

METHODS

The production of four inflammatory cytokines (interleukin-1 beta, tumor necrosis factor alpha, and IL-6 and IL-8) and one anti-inflammatory cytokine (IL-10) was tested using blood-derived monocytes from 12 healthy donors.

RESULTS

The Sambucol preparations increased the production of five cytokines (1.3-6.2 fold) compared to the control. Protec induced only a moderate production of IL-8 (1.6 fold) and IL-10 (2.3 fold) while Chizukit N caused only a moderate increase in IL-10 production (1.4 fold). Both Protec and Chizukit N caused moderate decreases in IL-1 beta, TNF alpha and IL-6 production. Lipopolysaccharide, a known activator of monocytes, induced the highest levels of cytokine production (3.6-10.7 fold).

CONCLUSIONS

The three Sambucol formulations activate the healthy immune system by increasing inflammatory and anti-inflammatory cytokines production, while the effect of Protec and Chizukit N is much less. Sambucol could therefore have immunostimulatory properties when administered to patients suffering from influenza (as shown before), or immunodepressed cancer or AIDS patients who are receiving chemotherapy or other treatments.

Propolis allergy. (III). Sensitization studies with minor constituents

87% of the propolis product "LB-1", originally reported to be 1,1-dimethyl-allyl caffeic acid ester, was shown by GC/MS analysis to consist of 3 isomeric pentenyl caffeates, 63% of which are 1,1-dimethylallyl caffeate. These pentenyl caffeates proved to be the major sensitizers of propolis and of poplar bud secretion in our previous study. In addition, 3 further minor allergens have now been investigated. Experimental sensitization indicates that phenylethyl caffeate is as strong a sensitizer as the major allergen "LB-1", while benzyl salicylate is a moderate sensitizer. Benzyl cinnamate plays only a subordinate role. At least 3 further esters of caffeic acid or cinnamic acid remain to be studied. Interestingly, relationships between propolis and balsam of Peru were found. 8 compounds are common to both materials. Thus "cross-reactions" or concomitant reactions in propolis-sensitive individuals to balsam of Peru are explainable.

The incidence of allergy to propolis in 605 consecutive patients patch tested in Prague

605 consecutive patients were patch tested with the standard CDRG test series and with a 10% alcoholic solution of propolis. Positive allergic reactions to propolis were observed in 25 patients (4.2%); thirteen of them exhibited a simultaneous positive patch test to balsam of Peru. In view of the relatively high incidence of allergic reactions and the appearance of pseudo-cross-sensitivity to another common allergen, balsam of Peru, propolis should not be used in topical medicaments or as a component of cosmetic preparations.

Allergy in beekeepers

Beekeepers represent a high-risk group for allergic disorders. They are affected by beestings but only a very limited fraction of the population develops severe anaphylactic symptoms. On the other hand several beekeepers have slight anaphylactic symptoms when they start working. Immunologically they are like "spontaneously desensitized subjects". They often have bee-venom specific IgE and all of them have very high titers of bee-venom specific IgG. Beekeepers may present an atopic sensitization to bee-hive dust and develop asthma and rhinitis. Finally, they may present a contact dermatitis to a bee-product: the propolis. This type of allergy is not very frequent.