Comparative neuroprotective effects of royal jelly and its unique compound 10-hydroxy-2-decenoic acid on ischemia-induced inflammatory, apoptotic, epigenetic and genotoxic changes in a rat model of ischemic stroke

OBJECTIVES

This study aimed to compare the efficacy of royal jelly (RJ) and its major fatty acid 10-hydroxy-2-decenoic acid (10-HDA) on ischemic stroke-related pathologies using histological and molecular approaches.

METHODS

Male rats were subjected to middle cerebral artery occlusion (MCAo) to induce ischemic stroke and were supplemented daily with either vehicle (control group), RJ or 10-HDA for 7 days starting on the day of surgery. On the eighth day, rats were sacrificed and brain tissue and blood samples were obtained to analyze brain infarct volume, DNA damage as well as apoptotic, inflammatory and epigenetic parameters.

RESULTS

Both RJ and 10-HDA supplementation significantly reduced brain infarction and decreased weight loss when compared to control animals. These effects were associated with reduced levels of active caspase-3 and PARP-1 and increased levels of acetyl-histone H3 and H4. Although both RJ and 10-HDA treatments significantly increased acetyl-histone H3 levels, the effect of RJ was more potent than that of 10-HDA. RJ and 10-HDA supplementation also alleviated DNA damage by significantly reducing tail length, tail intensity and tail moment in brain tissue and peripheral lymphocytes, except for the RJ treatment which tended to reduce tail moment in lymphocytes without statistical significance.

CONCLUSIONS

Our findings suggest that neuroprotective effects of RJ in experimental stroke can mostly be attributed to 10-HDA.

Biosynthesis of 10-Hydroxy-2-decenoic Acid through a One-Step Whole-Cell Catalysis

10-Hydroxy-2-decenoic acid (10-HDA) is an important component of royal jelly, known for its antimicrobial, anti-inflammatory, blood pressure-lowering, and antiradiation effects. Currently, 10-HDA biosynthesis is limited by the substrate selectivity of acyl-coenzyme A dehydrogenase, which restricts the technique to a two-step process. This study aimed to develop an efficient and simplified method for synthesizing 10-HDA. In this study, ACOX from Candida tropicalis 1798, which catalyzes 10-hydroxydecanoyl coenzyme A desaturation for 10-HDA synthesis, was isolated and heterologously coexpressed with FadE, Macs, YdiI, and CYP in Escherichia coli/SK after knocking out FadB, FadJ, and FadR genes. The engineered E. coli/AKS strain achieved a 49.8% conversion of decanoic acid to 10-HDA. CYP expression was improved through ultraviolet mutagenesis and high-throughput screening, increased substrate conversion to 75.6%, and the synthesis of 10-HDA was increased to 0.628 g/L in 10 h. This is the highest conversion rate and product concentration achieved in the shortest time to date. This study provides a simple and efficient method for 10-HDA biosynthesis and offers an effective method for developing strains with high product yields.

10-hydroxy-2-decenoic acid alleviates lipopolysaccharide-induced intestinal mucosal injury through anti-inflammatory, antioxidant, and gut microbiota modulation activities in chickens

Introduction

This study aimed to investigated the effects of 10-hydroxy-2-decenoic acid (10-HDA) on the growth performance, intestinal barrier, inflammatory response, oxidative stress, and gut microbiota of chickens challenged with lipopolysaccharide (LPS).

Methods

A total of 240 one-day-old chickens were randomly assigned to five treatment groups: (1) control group (basal diet + saline); (2) LPS group (basal diet + LPS); (3) Chlortetracycline (CTC) group (basal diet containing 75 mg/kg CTC + LPS); (4) 0.1% 10-HDA group (basal diet containing 1 g/kg 10-HDA + LPS); and (5) 0.5% 10-HDA group (basal diet containing 5 g/kg 10-HDA + LPS). All chickens were injected intraperitoneally with 0.5 mg/kg body weight of either LPS or saline at 17, 19, and 21 days of age.

Results

The results showed that dietary 10-HDA supplementation attenuated the loss in growth performance caused by the LPS challenge (p < 0.05). 10-HDA effectively alleviated LPS-induced intestinal mucosal injury, as evidenced by reduced bleeding, decreased serum diamine oxidase levels (p < 0.05), and increased villus/crypt ratios of the jejunum and ileum (p < 0.05). Dietary treatment with 0.1% 10-HDA reduced the concentrations of inflammatory cytokines (TNF-α, IL-1β, IL-6; p < 0.05), and increased immunoglobulin (IgA, IgG) and antioxidant enzyme levels (CAT, GSH-px, T-SOD) in the serum of LPS-challenged chickens (p < 0.05). These effects were similar to those observed in the CTC group. Moreover, 0.1% 10-HDA treatment reversed the LPS-induced variations in the mRNA expression of genes related to inflammation, antioxidant capacity, and intestinal tight junctions (p < 0.05). 16S rRNA analysis revealed that 10-HDA supplementation increased the relative abundance of Faecalibacterium and Clostridia_UCG-014 (p < 0.05). Additionally, it decreased the abundance of Clostridia_vadinBB60_group, Eubacterium_nodatum_group, and UC5-1-2E3 (p < 0.05). These changes were correlated with reduced inflammation and improved antioxidant capacity in the LPS-challenged chickens.

Conclusion

Collectively, dietary 10-HDA supplementation alleviated LPS-induced intestinal mucosal injury and the loss of growth performance through anti-inflammatory, antioxidant, and gut microbiota modulation activities in chickens. Moreover, 0.1% 10-HDA supplementation had comparable or even better protection for LPS-challenged chickens than supplementation with antibiotics or 0.5% 10-HDA. 10-HDA has the potential to be used as an alternative to antibiotics in protecting the intestinal health and improving the performance of poultry.

Oleic Acid Promotes the Biosynthesis of 10-Hydroxy-2-decenoic Acid via Species-Selective Remodeling of TAGs in Apis mellifera ligustica

This study aimed to assess the impact of oleic acid (OA) supplementation on the biosynthesis of 10-hydroxy-2-decenoic acid (10-HDA) in Apis mellifera ligustica. In experiment 1, varying concentrations of OA (2%, 4%, 6% and 8%) were added to an artificial diet for newly emerged bees reared in cages. Analysis of 10-HDA content and gene expression in the mandibular gland (MG) revealed that the 8% OA treatment had the greatest impact on promoting the synthesis of 10-HDA. Subsequent investigations utilized RNA-seq and lipidomics to characterize the molecular signature in the MG after feeding the 8% OA diet. Phosphatidylcholine (PC) and triacylglycerol (TAG) were found to be the predominant lipids in the MG of worker bees. A total of 154 TAGs were identified, with TAG (18:1-18:1-18:1) exhibiting the highest abundance, which increased by 1.5 times. The major TAG species contained palmitic acid (16:0) and oleic acid (18:1) in their structure, which was associated with fatty acid composition of diet. The increase in abundance of main TAGs may be attributed to the upregulation of glycerol-3-phosphate acyltransferase (Gpat) and glycerol kinase (GK) gene expression at the transcriptional level. The upregulation of differentially expressed genes (DEGs) related to carbohydrate metabolism may contribute to meeting the heightened metabolic demands of the MGs in worker bees. Royal jelly (RJ) samples from bee colonies fed with the 8% OA diet exhibited higher 10-HDA level than RJ collected from bee colonies fed with the artificial diet. These results indicate that 8% OA addition in the diet enhanced biosynthesis of 10-HDA in the mandibular gland, which was accompanied by significant and highly species-selective remodeling of TAGs.

Effects of 10-Hydroxy-2-decenoic Acid and 10-Hydroxydecanoic Acid in Royal Jelly on Bone Metabolism in Ovariectomized Rats: A Pilot Study

Although previous studies have demonstrated that royal jelly (RJ) may have estrogenic properties and prevent postmenopausal bone loss, the underlying mechanisms are not fully understood. This animal study aimed to investigate the effects of specific fatty acids of RJ, 10-hydroxy-2-decenoic acid (10H2DA) and 10-hydroxydecanoic acid (10HDAA), in ovariectomized rats. Ten-week-old female Wistar rats were divided into the Baseline, Sham, Ovx, Ovx + 10H2DA, and Ovx + 10HDAA groups. Rats in the Baseline group were sacrificed immediately, whereas those in the other groups were subjected to either a sham operation or bilateral ovariectomy. The animals in the Ovx + 10H2DA and Ovx + 10HDAA groups were fed diets containing 10H2DA and 10HDAA, respectively. Twelve weeks after surgery, the rats were sacrificed, and indices of bone mass and bone mechanics were analyzed. Femoral bone mineral density was significantly lower in the Ovx group than in the Sham group (p < 0.01). Administration of 10H2DA or 10HDAA did not ameliorate bone loss after ovariectomy. In addition, administration of these fatty acids diminished femur bone stiffness in ovariectomized rats (p < 0.01 and p < 0.05, respectively). These findings suggest that the favorable effects of RJ may not be exerted solely by 10H2DA or 10HDAA. However, these effects may be exhibited in combination with other RJ constituents.

The Potential Effect of Royal Jelly on Biomarkers Related to COVID-19 Infection and Severe Progression

Royal jelly is a yellowish to white gel-like substance that is known as a "superfood" and consumed by queen bees. There are certain compounds in royal jelly considered to have health-promoting properties, including 10-hydroxy-2-decenoic acid and major royal jelly proteins. Royal jelly has beneficial effects on some disorders such as cardiovascular disease, dyslipidemia, multiple sclerosis, and diabetes. Antiviral, anti-inflammatory, antibacterial, antitumor, and immunomodulatory properties have been ascribed to this substance. This chapter describes the effects of royal jelly on COVID-19 disease.

Trans-10-Hydroxy-2-Decenoic Acid Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice via Regulating the Inflammasome-Mediated Pyroptotic Pathway and Enhancing Colonic Barrier Function

SCOPE

The objective of this study is to explore the effects of 10-hydroxy-2-decenoic acid (10-HDA), the major fatty acid in royal jelly, on dextran sodium sulfate (DSS)-induced mice ulcerative colitis (UC) and its potential mechanism of action.

METHODS AND RESULTS

Forty male C57BL/6 mice are randomly divided into five experimental groups: control, DSS, DSS + 25 (or 100)mg kg^-1  d^-1 10-HDA, and DSS + 200 mg kg^-1  d^-1 mesalazine (ME). UC is induced in mice using 2.5% DSS in drinking water for 7 days. During the induction, these UC mice are orally administrated 10-HDA or ME per day. Meanwhile, lipopolysaccharide (LPS)/adenosine-triphosphate (ATP)-stimulated THP1 cells are used as a model to test the effects of 10-HDA. 10-HDA reduces DSS-induced pathological damage, reactive oxygen species (ROS) accumulation, neutrophil infiltration, and cytokine production in colonic tissue. Compared with the DSS group, the expressions of thioredoxin interacting protein (TXNIP), NOD-like receptor family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC), cysteinyl aspartate specific proteinase-1 (Caspase-1), gasdermin-D (GSDMD), N-terminal domain of gasdermin-D (N-GSDMD), interleukin-1β (IL-1β), and interleukin-18 (IL-18) in the colon are decreased after administration of 10-HDA. 10-HDA also elevates the barrier integrity and the expressions of zonula occludens-1 (ZO-1) and Occludin in colonic epithelium exposed to DSS. In THP1 cells, the inflammasome-mediated pyroptosis induced by LPS/ATP is inhibited by 10-HDA pretreatment.

CONCLUSION

10-HDA alleviates DSS-induced colitis by regulating the NLRP3 inflammasome-mediated pyroptotic pathway and enhancing colonic barrier function.

Production of 10-Hydroxy-2-decenoic Acid from Decanoic Acid via Whole-Cell Catalysis in Engineered Escherichia coli

10-Hydroxy-2-decenoic acid (10-HDA) is a terminal hydroxylated medium-chain α,β-unsaturated carboxylic acid that performs various unique physiological activities and has a wide market value. Therefore, development of an environmentally friendly, safe, and high-efficiency route to synthesize 10-HDA is required. Here, the β-oxidation pathway of Escherichia coli was modified and a P450 terminal hydroxylase (CYP153A33-CPR_BM3 ) was rationally designed to synthesize 10-HDA using decanoic acid as a substrate via two-step whole-cell catalysis. Different homologues of FadDs, FadEs, and YdiIs were analyzed in the first step of the conversion of decanoic acid to trans- -2- decenoic acid. In the second step, CYP153A33 (M228L)-CPR_BM3 efficiently catalyzed the conversion of trans- -2- decenoic acid to 10-HDA. Finally, 217 mg L^-1 10-HDA was obtained with 500 mg L^-1 decanoic acid. This study provides a strategy for biosynthesis of 10-HDA and other α, β-unsaturated carboxylic acid derivatives from specific fatty acids.

Anti-Biofilm and Anti-Hemolysis Activities of 10-Hydroxy-2-decenoic Acid against Staphylococcus aureus

Persistent infections caused by Staphylococcus aureus biofilms pose a major threat to global public health. 10-Hydroxy-2-decenoic acid (10-HDA), a main fatty acid in royal jelly, has been shown to possess various biological activities. The purpose of this study was to explore the effects of 10-HDA on the biofilms and virulence of S. aureus and its potential molecular mechanism. Quantitative crystal violet staining indicated that 10-HDA significantly reduced the biofilm biomass at sub-minimum inhibitory concentration (MIC) levels (1/32MIC to 1/2MIC). Scanning electron microscope (SEM) observations demonstrated that 10-HDA inhibited the secretion of extracellular polymeric substances, decreased bacterial adhesion and aggregation, and disrupted biofilm architecture. Moreover, 10-HDA could significantly decrease the biofilm viability and effectively eradicated the mature biofilms. It was also found that the hemolytic activity of S. aureus was significantly inhibited by 10-HDA. qRT-PCR analyses revealed that the expressions of global regulators sarA, agrA, and α-hemolysin gene hla were downregulated by 10-HDA. These results indicate that 10-HDA could be used as a potential natural antimicrobial agent to control the biofilm formation and virulence of S. aureus.

Formulation of Ocular In Situ Gels with Lithuanian Royal Jelly and Their Biopharmaceutical Evaluation In Vitro

Royal jelly is a natural substance produced by worker bees that possesses a variety of biological activities, including antioxidant, anti-inflammatory, antibacterial, and protective. Although fresh royal jelly is kept at low temperatures, to increase its stability, it needs to be incorporated into pharmaceutical formulations, such as in situ gels. The aim of this study was to formulate in situ ocular gels containing Lithuanian royal jelly for topical corneal use in order to increase the retention time of the formulation on the ocular surface and bioavailability. Gels were evaluated for physicochemical characteristics (pH, rheological properties, refractive index) and in vitro drug release measuring the amount of 10-hydroxy-2-decenoic acid (10-HDA). An ocular irritation test and cell viability tests were performed using the SIRC (Statens Seruminstitut Rabbit Cornea) cell culture line. Results indicated that all the in situ gels were within an acceptable pH and refractive index range close to corneal properties. Rheology studies have shown that the gelation temperature varies between 25 and 32 °C, depending on the amount of poloxamers. The release studies have shown that the release of 10-HDA from in situ gels is more sustained than royal jelly suspension. All gel formulations were non-irritant according to the short-time exposure test (STE) using the SIRC cell culture line, and long-term cell viability studies indicated that the formulations used in small concentrations did not induce cell death. Prepared in situ gels containing royal jelly have potential for ocular drug delivery, and they may improve the bioavailability, stability of royal jelly, and formation of non-irritant ocular formulations.

Health Promoting Properties of Bee Royal Jelly: Food of the Queens

Royal jelly (RJ) demand is growing every year and so is the market for functional foods in general. RJ is formed by different substances, mainly carbohydrates, proteins, and lipids, but also vitamins, minerals, and phenolic or volatile compounds in lower proportion. Major royal jelly proteins (MRJP) are, together with 10-hydroxy-2-decenoic acid (10-HDA), key substances of RJ due to their different biological properties. In particular, 10-HDA is a unique substance in this product. RJ has been historically employed as health enhancer and is still very relevant in China due to the traditional medicine and the apitherapy. Nowadays, it is mainly consumed as a functional food or is found in supplements and other formulations for its health-beneficial properties. Within these properites, anti-lipidemic, antioxidant, antiproliferative, antimicrobial, neuroprotective, anti-inflammatory, immunomodulatory, antiaging, and estrogenic activities have been reported for RJ or its specific components. This manuscript is aimed at reviewing the current knowledge on RJ components, their assessment in terms of authenticity, their biological activities, and related health applications.

The key royal jelly component 10-hydroxy-2-decenoic acid protects against bone loss by inhibiting NF-κB signaling downstream of FFAR4

The supplementation of royal jelly (RJ) is known to provide a variety of health benefits, including anti-inflammatory and anti-obesity effects. RJ treatment also reportedly protects against bone loss, but no single factor in RJ has yet been identified as an anti-osteoporosis agent. Here we fractionated RJ and identified 10-hydroxy-2-decenoic acid (10H2DA) as a key component involved in inhibiting osteoclastogenesis based on mass spectrometric analysis. We further demonstrated free fatty acid receptor 4 (FFAR4) as directly interacting with 10H2DA; binding of 10H2DA to FFAR4 on osteoclasts inhibited receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced activation of NF-κB signaling, thereby attenuating the induction of nuclear factor of activated T cells (NFAT) c1, a key transcription factor for osteoclastogenesis. Oral administration of 10H2DA attenuated bone resorption in ovariectomized mice. These results suggest a potential therapeutic approach of targeting osteoclast differentiation by the supplementation of RJ, and specifically 10H2DA, in cases of pathological bone loss such as occur in postmenopausal osteoporosis.

Determination of 10-Hydroxy-2-Decenoic Acid of Royal Jelly Using Near-Infrared Spectroscopy Combined with Chemometrics

A rapid quantitative analysis model for determining the hydroxy-2-decenoic acid (10-HDA) content of royal jelly based on near-infrared spectroscopy combining with PLS has been developed. Firstly, near-infrared spectra of 232 royal jelly samples with different 10-HDA concentrations (0.35% to 2.44%) were be collected. Second-order derivative processing of the spectra was carried out to construct a full-spectrum PLS model. Secondly, GA-PLS, CARS-PLS, and Si-PLS were used to select characteristic wavelengths from the second-order derivative spectrum to construct a PLS calibration model. Finally, 58 samples were used to select the best predictive model for 10-HDA content. The result show that the PLS model constructed after wavelength selection was significantly more accurate than the full spectrum model. The Si-PLS algorithm performed best and the corresponding characteristic wavelength range were: 980 to 1038, 1220 to 1278, 1340 to 1398, and 1688 to 1746 nm. The prediction results were RMSEP = 0.1496% and R_P = 0.9380. Hence, it is feasible to employ near-infrared spectra to analyze 10-HDA in royal jelly.

10-HDA, A Major Fatty Acid of Royal Jelly, Exhibits pH Dependent Growth-Inhibitory Activity Against Different Strains of Paenibacillus larvae

Paenibacillus larvae (P. larvae) is a bacterial pathogen causing American foulbrood (AFB), the most serious disease of honeybee larvae. The food of young larvae could play an important role in the resistance of larvae against AFB. It contains antibacterial substances produced by honeybees that may inhibit the propagation of the pathogen in larval midguts. In this study, we identified and investigated the antibacterial effects of one of these substances, trans-10-hydroxy-2-decenoic acid (10-HDA), against P. larvae strains including all Enterobacterial Repetitive Intergenic Consensus (ERIC) genotypes. Its inhibitory activities were studied by determining the minimum inhibitory concentrations (MICs). It was found that 10-HDA efficacy increases substantially with decreasing pH; up to 12-fold differences in efficacy were observed between pH = 5.5 and pH = 7.2. P. larvae strains showed different susceptibility to 10-HDA; up to 2.97-fold differences existed among various strains with environmentally important ERIC I and ERIC II genotypes. Germinating spores of the pathogen were generally more susceptible to 10-HDA than vegetative cells. Our findings suggest that 10-HDA could play significant role in conferring antipathogenic activity to larval food in the midguts of young larvae and contribute to the resistance of individual larvae to P. larvae.

Anti-Cancer and Protective Effects of Royal Jelly for Therapy-Induced Toxicities in Malignancies

Royal jelly (RJ) is a glandular secretion produced by worker honeybees and is a special food for the queen honeybee. It results in a significant prolongation of the lifespan of the queen honeybee compared with the worker honeybees through anti-inflammatory, anti-oxidant and anti-microbial activities. Consequently, RJ is used as cosmetic and dietary supplement throughout the world. In addition, in vitro studies and animal experiments have demonstrated that RJ inhibits cell proliferation and stimulates apoptosis in various types of malignant cells and affects the production of various chemokines, anti-oxidants and growth factors and the expression of cancer-related molecules in patients with malignancies, especially in patients treated with anti-cancer agents. Therefore, RJ is thought to exert anti-cancer effects on tumor growth and exhibit protective functions against drug-induced toxicities. RJ has also been demonstrated to be useful for suppression of adverse events, the maintenance of the quality of life during treatment and the improvement of prognosis in animal models and patients with malignancies. To understand the mechanisms of the beneficial effects of RJ, knowledge of the changes induced at the molecular level by RJ with respect to cell survival, inflammation, oxidative stress and other cancer-related factors is essential. In addition, the effects of combination therapies of RJ and other anti-cancer agents or natural compounds are important to determine the future direction of RJ-based treatment strategies. Therefore, in this review, we have covered the following five issues: (1) the anti-cancer effects of RJ and its main component, 10-hydroxy-2-decenoic acid; (2) the protective effects of RJ against anti-cancer agent-induced toxicities; (3) the molecular mechanisms of such beneficial effects of RJ; (4) the safety and toxicity of RJ; and (5) the future directions of RJ-based treatment strategies, with a discussion on the limitations of the study of the biological activities of RJ.

10-hydroxy-2-decenoic acid of royal jelly exhibits bactericide and anti-inflammatory activity in human colon cancer cells

BACKGROUND

Royal jelly (RJ), the exclusive food for the larva of queen honeybee, is regarded as the novel supplement to promote human health. The function of RJ may be attributed to its major and unique fatty acid, 10-hydroxy-2-decenoic acid (10-HDA). The current study investigated the anti-inflammory function of 10-HDA on human colon cancer cells, WiDr, as well as its effect on the growth of pathogenic bacterium.

METHODS

The pro-inflammatory cytokines, receptor antagonist cytokine (IL-1ra) and nuclear factor-kappa B (NF-κB) in WiDr cells was analyzed by Enzyme-linked immunosorbent assay (ELISA) or western blot. The growth inhibition of 10-HDA on bacterium was evaluated by determination of minimal inhibitory concentrations (MIC) and minimal bactericide concentrations (MBC).

RESULTS

The production of pro-inflammatory cytokines, Interleukin (IL)-8, IL-1β and tumor necrosis factor-alpha (TNF-α) in WiDr cells was modulated by 10-HDA. IL-8 were dramatically declined by 10-HDA at 3 mM, while IL-1β and TNF-α were significantly decreased. 10-HDA increased IL-1ra in a dose manner. NF-κB pathway is primarily in response to prototypical pro-inflammatory cytokines, and NF-κB was reduced after 10-HDA treatment. 10-HDA acted as potent bactericide against animal- or human-specific pathogens, including Staphylococcus aureus, Streptococcus alactolyticus, Staphylococcus intermedius B, Staphylococcus xylosus, Salmonella cholearasuis, Vibro parahaemolyticus and Escherichia coli (hemolytic).

CONCLUSIONS

The current study showed that in vitro 10-HDA from RJ exhibited anti-inflammatory activity in WiDr cells, as well as anti-bacterial activity against animal pathogens. 10-HDA showed its potential as anti-imflammtory agent and bactericide to benefit human gastrointestinal tract.

The functional property of royal jelly 10-hydroxy-2-decenoic acid as a melanogenesis inhibitor

BACKGROUND

It has been reported that royal jelly would reduce melanin synthesis and inhibit the expression of melanogensis related proteins and genes. In this study, we evaluate the anti-melanogenic and depigmenting activity of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly of Apis mellifera.

METHODS

In this study, we assesses the 10-HDA whitening activity in comparison with the changes in the intracellular tyrosinase activity, melanin content and melanin production related protein levles in B16F1 melanoma cells after treating with 10-HDA. Furthermore, the skin whitening effect was evaluated by applying a cream product containing with 0.5%, 1% and 2% of 10-HDA onto the skin of mice (C57BL/6 J) for 3 week to observe the effect of DL*-values.

RESULTS

The results showed that 10-HDA inhibited the MITF protein expression (IC50 0.86 mM) in B16F1 melanoma cells. Western blot analysis revealed that 10-HDA inhibited the activity of tyrosinase and the expression of tyrosinase-related protein 1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF) in B16F1 melanoma cells. In addition, the 10-HDA was applied on the skin of mice show significantly increased the average skin-whitening index (L value).

CONCLUSIONS

The validation data indicated the potential of 10-HDA for use in suppressing skin pigmentation. The 10-HDA is proposed as a candidate to inhibit melanogenesis, thus it could be developed as cosmetics skin care products.

The consumption of propolis and royal jelly in preventing upper respiratory tract infections and as dietary supplementation in children

Propolis and royal jelly (RJ), two important honeybee products, have been used commonly all over the world as traditional and ethnopharmacological nutrients since ancient times. Both of them have a lot of active ingredients which are known to be effective for several medical conditions. In this article, medical databases were searched for the usage of RJ and propolis in upper respiratory tract infections (URTI) and as a dietary supplementation, together and separately. 10-hydroxy-2-decenoic acid is the most prominent active compound showing antimicrobial effect within RJ. Caffeic acid phenethyl ester is the most famous one that shows antimicrobial and anti-inflammatory effect within propolis. When compared with propolis, RJ was found to have richer content for all three main nutrients; proteins, carbohydrates, and lipids. More clinical, experimental, and basic studies are needed to find out the best standardized mixture to cope with URTI in which RJ and propolis will be main ingredients in addition to the other secondary compounds that have health-beneficial effects.