Co-Reactivity of Fragrances and Fragrance-Markers in Patients With Positive Patch Tests to Chinese and Brazilian Propolis.

Compositional Differences Between Brazilian and Chinese Propolis.

ABSTRACTBackgroundIn Amsterdam, a steep increase in positive reactions to propolis in the European baseline series was observed from 2.8% in 2020 to 16.4% in 2023. We hypothesised that this was caused by the replacement of Chinese propolis by Brazilian propolis.ObjectivesTo test this hypothesis and to compare rates of positive patch tests to Brazilian propolis with those to Chinese popolis.Patients and MethodsIn a prospective study, 2 commercial Chinese propolis patch test samples were tested in consecutive patients in addition to Brazilian propolis.ResultsOf 239 patients patch tested, 57 (23.8%) had a positive reaction to Brazilian propolis, and 9 (3.8%) to Chinese propolis. Of the 57 reactions to Brazilian propolis, only 2 (3.5%) were found to be clinically relevant, versus 3/9 (33.3%) for Chinese propolis. Patients reacting to Brazilian propolis had significantly more co‐reactivities to fragrance mixes 1 and 2 and to limonene hydroperoxides than propolis B‐negative individuals.ConclusionsThe results confirm our hypothesis that the observed increase in positive patch tests to propolis between 2020 and 2023 was the result of the switch from Chinese to Brazilian propolis. The rates of reactions to both propolis samples from China were significantly lower than to Brazilian propolis.

Propolis was added to the European baseline series (EBS) in 2019. To investigate the frequency and relevance of positive patch tests to propolis in the EBS and to study co-reactivities. Retrospective study in patients patch tested between June 2019 and November 2023 in a university hospital in Amsterdam, The Netherlands. Of 3134 consecutive patients, 299 (9.5%) had a positive reaction to propolis 10% pet. Only nine reactions (3%) were judged to be clinically relevant. There were significant co-reactivities to Myroxylon pereirae resin (balsam of Peru), colophonium, fragrance mixes 1 and 2, and to limonene and linalool hydroperoxides. A steep increase in rates of positive reactions to propolis was observed from 2020 to 2023. This was highly likely the result of the replacement of Chinese propolis with Brazilian propolis by the manufacturer. Positive patch tests for propolis are very frequent in Amsterdam, but only a few of these reactions are relevant. Most are probably (pseudo-)cross-reactions in patients with fragrance allergies. Propolis in the EBS has very limited value for dermatologists and patients in The Netherlands. Changes in patch test materials should be provided to all users to avoid misinterpretation of patch test results.

BackgroundHydroperoxides of limonene and linalool are potent sensitizers.ObjectivesTo investigate the prevalence of contact allergy to both hydroperoxides of limonene and hydroperoxides of linalool, to report clinical relevance, and to investigate patient demographics.MethodsA total of 821 patients (35.6% male, mean age 42.4 years ± 17.8 years) were consecutively patch tested with our departmental baseline series and our fragrance series, including hydroperoxides of limonene 0.3% pet. and hydroperoxides of linalool 1.0% pet. The clinical relevance was assessed for all positive reactions.ResultsPositive patch test reactions to hydroperoxides of limonene and to hydroperoxides of linalool were observed in 77 patients (9.4%, 95% confidence interval [CI]: 7.4%‐11.4%) and in 96 patients (11.7%, 95%CI: 9.5%‐13.9%), respectively; 38 of these patients (4.6%, 95%CI: 3.2%‐6.0%) reacted to both. Most reactions were considered to be possibly or probably clinically relevant (66.3% and 68.8%, respectively), and a small proportion were deemed to be of certain clinical relevance (18.2% and 19.8%, respectively).ConclusionAs compared with previous studies, high numbers of positive reactions to both hydroperoxides of limonene and hydroperoxides of linalool were observed, the majority of which were clinically relevant, supporting their inclusion in the European baseline series.

Propolis is a natural product derived from plant resins collected by honeybees, and has been used globally as a folk medicine for centuries. More than 300 bio-active compounds have been identified from bee propolis. In the current study, we examined whether the ethanol extracts of Chinese and Brazilian propolis exert anticancer activities in four human colon carcinoma cell lines, CaCo2, HCT116, HT29 and SW480. Propolis samples were extracted with ethanol, and the crude extracts were dissolved in dimethylsulfoxide and used for the following experiments. We also examined the effects of the ethanol extract of Chinese propolis on cell proliferation, cell cycle progression, apoptosis, and the levels of expression of cell cycle control molecules in the HCT116 and HT29 cell lines. In the HCT116, HT29 and SW480 cell lines, the extracts of both Chinese and Brazilian propolis caused a marked dose-dependent growth inhibition, with IC50 values in the range of 4-41 μg/ml. In the FHC normal human colonic epithelial cell line, the extract of Chinese propolis failed to cause a marked growth inhibition, the growth inhibition rate was about 20%, whereas it was about 90% in the HCT116 and HT29 cell lines. In the HCT116 cell line, at concentrations of 10 and 20 μg/ml the extract of Chinese propolis caused a marked increase in sub-G1 fraction of cells in a dose-dependent fashion. The propolis extract (20 μg/ml) caused a significant increase of cells in sub-G1 and this increase was associated with a concomitant relative decrease of cells in the G1, S and G2-M phases of the cell cycle, indicating that Chinese propolis extract induced apoptosis in the HCT116 cell line. In addition, Chinese propolis extract caused a dose-dependent increase in the cellular mRNA levels of p21CIP1 and p53 in the HCT116 cell line. These findings indicate that the ethanol extracts of propolis contain components that may have anticancer activity. Thus, propolis and related products may provide a novel approach to the chemoprevention and/or chemotherapy of human colon carcinoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5645.

ABSTRACTBackgroundIn Amsterdam, in 2024, patch testing with Brazilian propolis yielded high rates of positive reactions (> 20%), whereas reactivity to Chinese propolis was significantly lower (3.5%). Differences in the composition were suggested as a possible explanation.Objectives1. To study the composition of 3 propolis samples (2 Chinese and 1 Brazilian) used for preparing commercial test allergens; 2. To study the influence of different enrichment times on the qualitative and quantitative composition of Brazilian propolis.Materials and MethodsAnalyses were performed using gas chromatography–mass spectrometry/flame ionisation detection (GC–MS/FID) of the volatile components obtained by headspace SPME (solid phase microextraction).ResultsA strong difference between the composition of the Brazilian propolis sample and both samples of Chinese propolis was found. Major ingredients in Brazilian propolis were hydrocinnamic acid (16.9%), (E)‐nerolidol (7.41%), spathulenol (5.45%) and junenol (4.01%). Major ingredients in Chinese propolis were (E)‐cinnamyl alcohol (8.08% and 24.96%), 2‐phenethyl alcohol (8.93% and 11.25%), α‐curcumene (8.77% and 8.81%) and guaiol (5.96% and 5.72%).ConclusionsThe volatile fractions of Brazilian propolis and Chinese propolis used for patch testing have very different compositions. Whether this causes or contributes to the differences in patch test reactivity has to be investigated further.

To establish a biological method for evaluating propolis and to reveal their anti-allergic action, the effects of the ethanol and water extracts (EA-ET and WA-WT, respectively) from Brazilian, Chinese and Japanese propolis on the histamine release induced by compound 48/80 and concanavalin A (Con A) were investigated. The relation between the inhibitory activities of these extracts on the histamine release and their E(1 cm)1% values were also examined. As a result, the following was found: 1) 0.003-0.01% ethanol and 0.03-0.1% water extracts inhibited the histamine release induced by compound 48/80 and Con A, and the inhibitory potencies of the former extracts were more than 10 times stronger than those of the latter extracts, making it clear that both the ethanol and water extracts possess an anti-allergic action; 2) most of the ethanol and water extracts responded to the histamine release induced by both the histamine releasers in a concentration-dependent manner; 3) the inhibitory activities of 0.003% EM from Hebei Province, EP from Sichuan Province, EQ from Zhejiang Province and ER from Anhui Province in China were weaker than those of 0.01% corresponding extracts, whereas 0.001% ED-EH from Brazilian propolis, EM, EN from Henan Province in China and EP-ER promoted the Con A-induced histamine release of more than 10%, suggesting that such extracts must be carefully given to humans; 4) the inhibitory potencies of only 0.03-0.1% water extracts from Chinese propolis on the Con A-induced histamine release related excellently with their E(1 cm)1% values; 5) from the results of the relation between the inhibitory potencies of the propolis extracts and their E(1 cm)1% values, it was suggested that an unknown compound, being a poorly water-soluble compound which is a non-flavonoid, with an anti-allergic action is contained in propolis; 6) to precisely evaluate the anti-allergic action of the propolis, the biological method, which measures the inhibitory activities of the propolis extracts on histamine release, was markedly superior to the physicochemical method.

Background: Prevalence of positive patch test (ppt) reactions to propolis in Europe has varied with different allergen source origins. Compared with previous cycles, the North American Contact Dermatitis Group (NACDG) noted a marked increase in propolis positivity in 2019-2020.Objective: To compare propolis positivity in North American centers between 3 periods (2019, 2020, and 2021/2022), based on geographic origin and supplier.Methods: Retrospective analysis of NACDG patch test data (2019-2022) utilizing 3 different sources of propolis: Chinese propolis (Allergeaze-CPA), Chinese propolis (Chemotechnique-CPC), and Brazilian propolis (Allergeaze-BPA).Results: Proportions of ppt reactions to propolis were: 3.7% (84/2260) to CPA in 2019, 14.7% (271/1838) to BPA in 2020, and 2.2% (66/3052) to CPC in 2021/2022. There was a statistically significant difference in prevalence of reactions for BPA compared with both CPA and CPC (P < 0.00001).Conclusions: When unexpected changes are noted in patch test positivity, especially with naturally derived allergens, the reasons behind those changes should be investigated. The substitution of Brazilian for Chinese propolis resulted in a significant increase in ppt reactions.

Contact allergy to hydroperoxides of limonene and linalool in a pediatric population

Cross-sectional evaluation of the pediatric baseline series in detection of contact sensitization in children

Dietary supplementation with polyphenol-rich propolis can protect against experimentally induced colitis. We examined whether different polyphenol compositions of Chinese propolis (CP) and Brazilian propolis (BP) influence their ability to protect against dextran sulfate sodium (DSS)-induced colitis in rats. HPLC-DAD/Q-TOF-MS analysis confirmed that polyphenol compositions of CP and BP were dissimilar. Rats were given CP or BP by gavage (300 mg kg-1 body weight) throughout the study, starting 1 week prior to DSS treatment for 1 week followed by 3 d without DSS. CP and BP significantly reduced the colitis disease activity index relative to controls not receiving propolis, prevented significant DSS-induced colonic tissue damage, and increased resistance to DSS-induced colonic oxidative stress as shown by reduced malonaldehyde levels and increased T-AOC levels. CP and BP significantly reduced DSS-induced colonic apoptosis. Colonic inflammatory markers IL-1β, IL-6, and MCP-1 were suppressed by CP and BP, whereas only BP-induced expression of TGF-β. CP, not BP, increased the diversity and richness of gut microbiota populations. Both forms of propolis significantly reduced populations of Bacteroides spp. Despite the dissimilar polyphenol compositions of CP and BP, their ability to protect against DSS-induced colitis is similar. Nevertheless, some different physiological impacts were observed.

The aim of this work was to investigate the antioxidant property of honeybee products and their constituents using an ESR method. Antioxidative activity was evaluated as the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging activities, in descending order, were: ethanol extract of Chinese red propolis>ethanol extract of Brazilian green propolis>water extract of Brazilian green propolis>ethanol extract of bee pollen. Many natural compounds are included in Brazilian green propolis, such as caffeoylquinic acid derivatives [3,4-di-caffeoylquinic acid (3,4-CQA), 3,5-di-caffeoylquinic acid (3,5-CQA), and chlorogenic acid (ChA)] and cinnamic acid derivatives [artepillin C, baccharin, rho-coumaric acid, and drupanin]. Caffeoylquinic acid derivatives exhibited DPPH radical scavenging activity as strong as that of ascorbic acid and trolox. Among the cinnamic acid derivatives, artepillin C exhibited relatively strong DPPH radical scavenging activity. Caffeic acid phenethyl ester (CAPE), a constituent of Chinese red propolis, exhibited potent DPPH radical scavenging activity, stronger than that of ascorbic acid and trolox. Caffeic acid, a metabolite of caffeoylquinic acid, exhibited powerful DPPH radical scavenging activity, while quinic acid, another metabolite of caffeoylquinic acid, had no such activity. Both Brazilian and Chinese propolis and their constituents (caffeoylquinic acid derivatives and CAPE) therefore appear to be powerful scavengers of DPPH radical, and the effects may be partly dependent on the nature of their caffeoyl groups.

Contact allergy rates of linalool and limonene hydroperoxides (HPs) have increased. To demonstrate the patterns of simultaneous positive patch test (PT) reactions and prevalences of multiple contact allergies (MCAs) in patients with contact allergy to linalool and/or limonene HPs. A retrospective analysis of consecutive dermatitis patients in 2015-2020 was performed. Of all 4192 patients, 1851 had at least one positive PT reaction. Of these, 410 (22.2%) had MCAs, significantly related to a higher age (p-value = 0.003). Patients with an exclusively positive reaction to linalool HPs but not limonene HPs were shown to have MCAs (p-value <0.001, odds ratio (95% confidence interval) = 4.15 (3.01-5.73)). Patients with simultaneous contact allergies to both linalool and limonene HPs had contact allergies to many other screening and fragrance allergens. Simultaneous positive PT reactions to allergens in baseline series and fragrances are common in patients with the HPs contact allergy, especially linalool HPs. The pattern of simultaneous PT reactions principally suggested the co-sensitization of the cosmetic allergens.

Objectives The determination of chemical components is usually used in the quality control of propolis. However, chemical components from different types of propolis are similar. The objective of this investigation was to establish a method based on a specific chemical fingerprint profile and a multivariate mixed model statistical analysis which could easily distinguish propolis of different origins and promote the quality control of propolis. Methods A novel approach using high performance liquid chromatography (HPLC) coupled with multivariate statistical analysis was established for profiling and distinguishing Chinese and Brazilian green propolis. A batch of 22 propolis samples was analyzed, and the datasets on retention time, peak area and sample codes were subjected to mixed multivariate statistical analysis consisting of principal component analysis (PCA) and a self-organization mapping net (SOM). Results The fingerprints were profiled. PCA score plots showed Chinese and Brazilian green propolis clearly classified into two groups. The visualized SOM results showed data from the two groups projected to the adjacent neurons clearly separated from each other. Artepillin C, which contributed greatly to the differentiation, was screened out and identified as the reference compound. Artepillin C is the characteristic component in Brazilian propolis which can be used as chemical marker to distinguish propolis of different origins. Conclusions In this study, fingerprints coupled with multivariate statistical analysis have been successfully applied to distinguish Chinese from Brazilian green propolis. The research identified a chemical marker, and thus helps to investigate and promote the quality control of propolis.

Limonene and linalool are widely used fragrances in cosmetic and household products. Upon air exposure, they autoxidise into potent sensitisers - hydroperoxides of limonene (Lim-OOH) and linalool (Lin-OOH). The objective of this study is to investigate patch test reactions to Lim-OOH and Lin-OOH, and associated characteristics, reaction patterns, including doubtful reactions and co-reactivity with other fragrance allergens. A retrospective analysis was conducted using registry data from 6719 consecutively patch-tested patients at Gentofte Hospital, Denmark (2014-2025). Doubtful reactions were clinically subclassified as erythematous, only (E) or infiltrated (I). The prevalence of positive patch test reactions was 1.6% for Lim-OOH and 3.1% for Lin-OOH. Positive Lim-OOH reactions were less likely in men and in patients with atopic, occupational or hand dermatitis, whilst positive Lin-OOH reactions were more likely in those > 40 years and less in atopic dermatitis. Most reactions peaked on day 3/4 and were weakly positive. Doubtful I reactions more frequently progressed to positive than doubtful E. Co-reactivity was observed between Lim-OOH, Lin-OOH and other fragrance allergens. Lower test concentrations reduced diagnostic sensitivity. Co-reactivity with other fragrance allergens supports true allergenicity. The currently recommended patch test concentrations (0.3% Lim-OOH and 1.0% Lin-OOH) seem optimal and qualify for inclusion in the European baseline series.