Influence of Diet-Induced Obesity on the Bioavailability and Metabolism of Raspberry Ketone (4-(4-Hydroxyphenyl)-2-Butanone) in Mice

The improvement of tyrosol bioavailability by encapsulation into liposomes using pH-driven method

To improve the poor water solubility and oral bioavailability of tyrosol, novel tyrosol liposomes (Tyr-LPs) were prepared by pH-driven method. Fourier transform infrared (FTIR) absorption spectra and X-ray diffraction (XRD) analysis indicated that Tyr-LPs were successfully encapsulated and tyrosol was in an amorphous state in liposomes. When tyrosol content in Tyr-LP was 1.33 mg/ml and the Tyr:LP (mass ratio) = 1:2, favorable dispersibility of Tyr-LP was exhibited, with an instability index of 0.049 ± 0.004, PDI of 0.274 ± 0.003, and the EE of 94.8 ± 2.5 %. In vivo pharmacokinetic studies showed that after oral administration of tyrosol or Tyr-LP (Tyr:LP = 1:2), concentration-versus-time curve (AUC0-720mins) and maximum concentration (Cmax) values of Tyr-LP was respectively 1.5-fold (P < 0.01) and 2.25-fold (P < 0.01) higher than tyrosol, which indicated that the oral bioavailability of tyrosol was effectively improved in Tyr-LPs. Our study thereby provides theoretical support for the application of Tyr-LP for optimal delivery of tryosol.

Raspberry Ketone Prevents LPS-Induced Depression-Like Behaviors in Mice by Inhibiting TLR-4/NF-κB Signaling Pathway via the Gut-Brain Axis

SCOPE

Depression, a prevalent mental disorder, has significantly impacted the lives of 350 million people, yet it holds promise for amelioration through food-derived phenolics. Raspberries, renowned globally for their delectable flavor, harbor a phenolic compound known as raspberry ketone (RK). However, the impact of RK on depressive symptoms remains ambiguous. This study aims to investigate the impact of RK on lipopolysaccharide (LPS)-induced depressed mice and elucidates its potential mechanisms, focusing on the gut-brain axis.

METHODS AND RESULTS

Through behavioral tests, RK exerts a notable preventive effect on LPS-induced depression-like behaviors in mice. RK proves capable of attenuating gut inflammation, repairing gut barrier impairment, modulating the composition of the gut microbiome (Muribaculaceae, Streptococcus, Lachnospiraceae, and Akkermansia), and promoting the production of short-chain fatty acids. Furthermore, RK alleviates neuroinflammation by suppressing the TLR-4/NF-κB pathway and bolsters synaptic function by elevating levels of neurotrophic factors and synapse-associated proteins.

CONCLUSION

The current study provides compelling evidence that RK effectively inhibits the TLR-4/NF-κB pathway via the gut-brain axis, leading to the improvement of LPS-induced depression-like behaviors in mice. This study addresses the research gap in understanding the antidepressant effects of RK and illuminates the potential of utilizing RK as a functional food for preventing depression.

Oral supplementation of Gordonibacter urolithinfaciens promotes ellagic acid metabolism and urolithin bioavailability in mice

Ellagic acid (EA) is an abundant dietary polyphenol with multifarious health benefits but low bioavailability. To increase its bio-efficacy, converting EA to urolithins by supplementing urolithin-producing bacteria, e.g., Gordonibacter urolithinfaciens (G.uro), could be a solution. This work first tested three methods for oral delivery of live G.uro. Intestinal colonization of G.uro and its impact on local gut microbiota, EA-to-urolithin conversion and bioavailability were then investigated in C57BL/6J mice administered to EA only or a synbiotic (G. uro + EA). In vitro results suggested that G.uro largely survived simulated gastrointestinal digestion and could be administered without protection. In vivo results showed that G.uro had little impact on local gut microbiota but could not colonize the gut. Moreover, synbiotic remarkably promoted Akkermansia, Lactobacillus and Bifidobacterium growth, and significantly enhanced the bioavailability of urolithins compared with the EA-only group. This study demonstrated the potential of oral supplementation of G.uro for enhancing EA-to-urolithin bioconversion and bioavailability.

Gut-derived 4-hydroxyphenylacetic acid attenuates sepsis-induced acute kidney injury by upregulating ARC to inhibit necroptosis

BACKGROUND

Studies have found that the plasma content of gut-derived 4-hydroxyphenylacetic acid (4-HPA) was significantly increased in septic patients. However, the mechanism of 4-HPA elevation during sepsis and its relationship with sepsis-induced acute kidney injury (SAKI) remain unclear.

METHODS

Cecal ligation and puncture (CLP) was performed in C57BL/6 mice to establish the SAKI animal model. Human renal tubular epithelial (HK-2) cells stimulated with lipopolysaccharide were used to establish the SAKI cell model. The widely targeted metabolomics was applied to analyze the renal metabolite changes after CLP. Proteomics was used to explore potential target proteins regulated by 4-HPA. The blood sample of clinical sepsis patients was collected to examine the 4-HPA content.

RESULTS

We found that renal gut-derived 4-HPA levels were significantly increased after CLP. The high permeability of intestinal barrier after sepsis contributed to the dramatic increase of renal 4-HPA. Intriguingly, we demonstrated that exogenous 4-HPA administration could further significantly reduce CLP-induced increases in serum creatinine, urea nitrogen, and cystatin C, inhibit renal pathological damage and apoptosis, and improve the survival of mice. Mechanistically, 4-HPA inhibited necroptosis in renal tubular epithelial cells by upregulating the protein expression of apoptosis repressor with caspase recruitment domain (ARC) and enhancing the interaction between ARC and receptor-interacting protein kinase 1 (RIPK1).

CONCLUSIONS

The increase of gut-derived 4-HPA in the kidney after sepsis could play a protective effect in SAKI by upregulating ARC to inhibit necroptosis.

Ethnopharmacology of Rubus idaeus Linnaeus: A critical review on ethnobotany, processing methods, phytochemicals, pharmacology and quality control

ETHNOPHARMACOLOGICAL RELEVANCE

Rubus idaeus Linnaeus (RI) is a Chinese herbal medicine that has been widely used in China for a long time to reinforce the kidney, nourish the liver, improve vision, and arrest polyuria.

AIM OF THE STUDY

This work aims to evaluate the recent progress of the chemical composition, pharmacological activity, pharmacokinetics, metabolism, and quality control and of Rubus idaeus, which focuses on the insufficiency of existing research and will shed light on future studies of Rubus idaeus.

METHODS

Literatures about "Rubus idaeus","Red raspberry" and "Fupenzi"are retrieved by browsing the database, such as Web of Science (http://www.webofknowledge.com/wos), Pubmed (https://pubmed.ncbi.nlm.nih.gov/), CNKI (http://www.cnki.net/), and Wanfang Data (http://www.wanfangdata.com.cn). In addition, related textbooks and digital documents are interrogated to provide a holistic and critical review of the topic. The period of the literature covered from 1981 to 2022.

RESULTS

Approximately 194 compounds have been isolated from Rubus idaeus, which is rich in phenols, terpenoids, alkaloids, steroids, and fatty acids. Numerous investigations have demonstrated that Rubus idaeus exhibits many pharmacological activities, including hypoglycemic and hypolipidemic, anti-Alzheimer effect, anti-osteoporosis, hepatoprotective, anti-cancer, neuroprotective, anti-bacteria and skin care, etc. However, it is worth noting that most of the research is not associated with the conventional effect, such as reducing urination and treating opacity of the cornea.

CONCLUSION

The effectiveness of Rubus idaeus has been proved by its long-term clinical application. The research on the pharmacological activity of Rubus idaeus has flourished. In many pharmacological experiments, only the high-dose group can achieve the corresponding efficacy, so the efficacy of Rubus idaeus needs to be further interrogated. Meanwhile, the relationship between pharmacological activity and specific compounds of Rubus idaeus has not been clarified yet. Last but not least, studies involving toxicology and pharmacokinetics are very limited. Knowledge of bioavailability and toxicological behavior of Rubus idaeus can help understand the herb's pharmacodynamic and safety profile.

Rhododendrol, a reductive metabolite of raspberry ketone, suppresses the differentiation of 3T3‑L1 cells into adipocytes

Obesity is a serious medical condition worldwide, and a major risk factor for type 2 diabetes, metabolic syndrome, cancer and cardiovascular disease. In addition to changes in dietary habits and physical activity, consuming supplements to maintain good health and prevent obesity is important in modern society. Raspberry ketone (RK) is a natural phenolic ketone found in the European red raspberry (Rubus idaeus L.) and is hypothesized to prevent obesity when administered orally. The present study found that RK was reduced to rhododendrol (ROH) in human liver microsomes and cytosol. The present study investigated whether the metabolite ROH had anti‑adipogenic effects using mouse 3T3‑L1 cells. The effects of ROH or RK on lipid accumulation during differentiation of 3T3‑L1 pre‑adipocyte into adipocyte were determined using Oil Red O staining. CCAAT enhancer‑binding protein α (C/EBPα) and peroxisome proliferator‑activated receptor γ (PPARγ) mRNA and protein expression were examined using reverse transcription‑quantitative PCR and western blotting analysis, respectively. The present study revealed that ROH suppressed lipid accumulation in the cells, similar to RK. In addition, ROH suppressed the mRNA expression levels of C/EBPα and PPARγ in 3T3‑L1 adipocytes. Furthermore, ROH suppressed PPARγ protein expression in 3T3‑L1 adipocytes. These findings suggested that ROH is an active metabolite with an anti‑adipogenic effect, which may contribute to the anti‑obesity effect of orally administered RK. The present study indicated that it is important to understand the biological activity of the metabolites of orally administered compounds.

Metabolic gene signature in white adipose tissue of oral doses raspberry ketone [4-(4-hydroxyphenyl)-2-butanone] that prevent diet-induced weight gain and induce loss of righting reflex

Raspberry ketone (RK; [4-(4-hydroxyphenyl)-2-butanone]) is a synthetic flavoring agent and dietary supplement for weight control. This study investigated the metabolic signature of oral doses of RK that prevent weight gain or promote loss of righting reflex (LORR) in C57Bl/6J mice. Daily RK 200 mg/kg prevented high-fat diet (HFD; 45% Kcal fat) fed weight gain (∼8% reduction) over 35 days. RNA-seq of inguinal white adipose tissue (WAT) performed in males revealed 12 differentially expressed genes. Apelin (Apln) and potassium voltage-gated channel subfamily C member (Kcnc3) expression were elevated with HFD and normalized with RK dosing, which was confirmed by qPCR. Acute RK 640 mg/kg produced a LORR with a <5 min onset with a >30 min duration. Acute RK 200 mg/kg increased gene expression of Apln, Kcnc3, and nuclear factor erythroid 2-related factor 2 (Nrf2), but reduced acetyl-COA carboxylase (Acc1) and NAD(P)H quinone dehydrogenase 1 (Nqo1) in inguinal WAT. Acute RK 640 mg/kg elevated interleukin 6 (Il 6) and heme oxygenase 1 (Hmox1) expression, but reduced Nrf2 in inguinal and epididymal WAT. Our findings suggest that RK has a dose-dependent metabolic signature in WAT associated with either weight control or LORR.

The signatures of liver metabolomics and gut microbiota in high-fat diet fed mice supplemented with rhododendrol

As aromatic compounds found within red fruits and berries, raspberry ketones (RK) have the potential for nonalcoholic fatty liver disease (NAFLD) amelioration. However, the mechanism of RK on NAFLD is unclear, and their bioactive metabolite is unknown. As the major metabolites of RK that are mainly distributed in the liver, rhododendrol (RHO) is used in our current study to test whether RHO accounts for the beneficial effect of RK on NAFLD and the underlying mechanism. In a 16-week trial, RHO significantly decreased final body weight, improved serum lipid profile and ameliorated liver inflammation. Moreover, RHO changed the gut microbiota composition, including lean phenotype-related genera, such as Bacteroides, Bilophila, Oscillibacter, Lachnospiraceae_bacterium_28_4 and Bacteroides sartorii. Liver metabolomics analysis indicated that RHO enhanced the abundance of metabolites related to alanine, aspartate, and glutamate metabolism, as well as arginine and proline metabolism. Spearman correlation analysis revealed that these metabolites were positively correlated with the gut genera enriched by RHO. Here, our findings suggested that the metabolic effects of RK might be partially attributed to its metabolite-RHO, and mice supplemented with RHO have dramatically altered hepatic metabolisms concurrent with shifts in specific gut bacteria.

Chemical Compounds of Berry-Derived Polyphenols and Their Effects on Gut Microbiota, Inflammation, and Cancer

Berry-derived polyphenols are bioactive compounds synthesized and secreted by several berry fruits. These polyphenols feature a diversity of chemical compounds, including phenolic acids and flavonoids. Here, we report the beneficial health effects of berry-derived polyphenols and their therapeutical application on gut-microbiota-related diseases, including inflammation and cancer. Pharmacokinetic investigations have confirmed the absorption, availability, and metabolism of berry-derived polyphenols. In vitro and in vivo tests, as well as clinical trials, showed that berry-derived polyphenols can positively modulate the gut microbiota, inhibiting inflammation and cancer development. Indeed, these compounds inhibit the growth of pathogenic bacteria and also promote beneficial bacteria. Moreover, berry-derived polyphenols exhibit therapeutic effects against different gut-microbiota-related disorders such as inflammation, cancer, and metabolic disorders. Moreover, these polyphenols can manage the inflammation via various mechanisms, in particular the inhibition of the transcriptional factor Nf-κB. Berry-derived polyphenols have also shown remarkable effects on different types of cancer, including colorectal, breast, esophageal, and prostate cancer. Moreover, certain metabolic disorders such as diabetes and atherosclerosis were also managed by berry-derived polyphenols through different mechanisms. These data showed that polyphenols from berries are a promising source of bioactive compounds capable of modulating the intestinal microbiota, and therefore managing cancer and associated metabolic diseases. However, further investigations should be carried out to determine the mechanisms of action of berry-derived polyphenol bioactive compounds to validate their safety and examinate their clinical uses.

Odorant Metabolism in Humans

Odorants are relatively small molecules which are easily taken up and distributed in the human body. Despite their relevance in everyday life, however, only a limited amount of evidence about their metabolism, pathways, and bioactivities in the human body exists. With this Review, we aim to encourage future interdisciplinary research on the function and mechanisms of the biotransformation of odorants, involving different disciplines such as nutrition, medicine, biochemistry, chemistry, and sensory sciences. Starting with a general overview of the different ways of odorant uptake and enzymes involved in the metabolism of odorants, a more precise description of biotransformation processes and their function in the oral cavity, the nose, the lower respiratory tract (LRT), and the gastrointestinal tract (GIT) is given together with an overview of the different routes of odorant excretion. Finally, perspectives for future research are discussed.

Recent Analytical Approaches for the Study of Bioavailability and Metabolism of Bioactive Phenolic Compounds

The study of the bioavailability of bioactive compounds is a fundamental step for the development of applications based on them, such as nutraceuticals, functional foods or cosmeceuticals. It is well-known that these compounds can undergo metabolic reactions before reaching therapeutic targets, which may also affect their bioactivity and possible applications. All recent studies that have focused on bioavailability and metabolism of phenolic and terpenoid compounds have been developed because of the advances in analytical chemistry and metabolomics approaches. The purpose of this review is to show the role of analytical chemistry and metabolomics in this field of knowledge. In this context, the different steps of the analytical chemistry workflow (design study, sample treatment, analytical techniques and data processing) applied in bioavailability and metabolism in vivo studies are detailed, as well as the most relevant results obtained from them.

Potential metabolic activities of raspberry ketone

Novel food and food compounds interventions have attracted a lot of attention nowadays for the prevention and treatment of metabolic diseases. Raspberry ketone (RK) is aromatic compound found within red fruits and berries, has been used as an over-the-counter product for weight loss. However, actually, the effect of RK on weight loss is still controversial, and the mechanism is largely unknown. Besides, in vivo and in vitro studies have demonstrated the beneficial effect of RK on the development of other metabolic diseases. In this review, we comprehensively highlighted the synthesis, bioavailability, and metabolism of RK, and summarized the progress made in our understanding of the potential biological activities of RK, including antiobesity, antidiabetes, cardioprotection, and hepatoprotection, as well as their underlying mechanisms. This paper provides a critical overview about the current findings and proposes the future studies in the area of RK on human health. PRACTICAL APPLICATIONS: Raspberry ketone (RK) has been used for weight control for years, but this effect is controversial considering food intake. Additionally, RK is beneficial for T2DM, liver and heart injury. The underlying mechanisms of the protective effect of RK including accelerating fatty acid oxidation, balancing serum glucose level, anti-inflammation, antioxidant process, and so on. In this context, we provide a comprehensive analysis of the benefits of RK against many metabolic diseases and discuss the underlying molecular mechanisms. We hope our work will be helpful for further researches on RK and improve its public recognition.

Levels of polyphenols and phenolic metabolites in breast milk and their association with plant-based food intake in Hong Kong lactating women

Dietary polyphenols are phytonutrients exhibiting multiple health benefits in humans including those in infants. However, data on breast milk (poly)phenolic composition are limited, especially among Asian populations. This study aimed to assess the levels of dietary polyphenols and their microbial-derived metabolites in the breast milk of Hong Kong lactating women, and how maternal diet correlated with the phenolic composition in breast milk. Breast milk samples from 89 healthy Hong Kong lactating women (aged 19-40 years) were collected. Maternal intake of plant-based foods and polyphenols was estimated through 3-day dietary records and the Phenol-Explorer database. Twelve commonly consumed polyphenols including their microbial-derived metabolites in breast milk were quantified using an optimized and validated UHPLC-MS/MS method. The effect of maternal intake on breast milk phenolic levels was then examined via the Pearson correlation test. The mean concentrations of individual phenolic compounds ranged from 5.1 nmol L^-1 (chlorogenic acid) to 731.5 nmol L^-1 (3,4-dihydroxybenzoic acid). Despite suboptimal intake of fruits and vegetables among our participants, breast milk phenolic levels were comparable to those of foreign populations. Significant correlations were found between dietary intake and multiple phenolics, particularly legume and daidzein (r = 0.33, P = 0.001), and tea and epicatechin (r = 0.30, P = 0.03). Regarding phenolic metabolites, 3,4-dihydroxyphenylacetic acid was significantly correlated with several polyphenols, particularly quercetin (r = 0.34, P = 0.002), and equol was exclusively correlated with daidzein (r = 0.46, P < 0.001). Our findings support that intake of plant-based foods significantly affects breast milk phenolic composition. Future investigation on the bioavailability and health outcomes in infants is warranted to substantiate the transferability of these bioactive phytonutrients from mother to child through lactation, and to promote maternal intake of polyphenol-rich foods.

Reduced Body Fat and Epididymal Adipose Apelin Expression Associated With Raspberry Ketone [4-(4-Hydroxyphenyl)-2-Butanone] Weight Gain Prevention in High-Fat-Diet Fed Mice

Raspberry ketone [4-(4-hydroxyphenyl)-2-butanone] is a natural aromatic compound found in raspberries and other fruits. Raspberry ketone (RK) is synthetically produced for use as a commercial flavoring agent. In the United States and other markets, it is sold as a dietary supplement for weight control. The potential of RK to reduce or prevent excessive weight gain is unclear and could be a convergence of several different actions. This study sought to determine whether acute RK can immediately delay carbohydrate hyperglycemia and reduce gastrointestinal emptying. In addition, we explored the metabolic signature of chronic RK to prevent or remedy the metabolic effects of diet-induced weight gain. In high-fat diet (HFD; 45% fat)-fed male mice, acute oral gavage of RK (200 mg/kg) reduced hyperglycemia from oral sucrose load (4 g/kg) at 15 min. In HFD-fed female mice, acute oral RK resulted in an increase in blood glucose at 30 min. Chronic daily oral gavage of RK (200 mg/kg) commencing with HFD access (HFD_RK) for 11 weeks resulted in less body weight gain and reduced fat mass compared with vehicle treated (HFD_Veh) and chronic RK starting 4 weeks after HFD access (HFD_RKw4) groups. Compared with a control group fed a low-fat diet (LFD; 10% fat) and dosed with vehicle (LFD_Veh), glucose AUC of an oral glucose tolerance test was increased with HFD_Veh, but not in HFD_RK or HFD_RKw4. Apelin (Apln) gene expression in epididymal white adipose tissue was increased in HFD_Veh, but reduced to LFD_Veh levels in the HFD_RK group. Peroxisome proliferator activated receptor alpha (Ppara) gene expression was increased in the hepatic tissue of HFD_RK and HFD_RKw4 groups. Overall, our findings suggest that long term daily use of RK prevents diet-induced weight gain, normalizes high-fat diet-induced adipose Apln, and increases hepatic Ppara expression.

Development and validation of a micro-QuEChERS method with high-throughput enhanced matrix removal followed with UHPLC-QqQ-MS/MS for analysis of raspberry ketone-related phenolic compounds in adipose tissues

Raspberry ketone (RK) is a major flavor compound in red raspberries, and it has been marketed as a popular weight-loss dietary supplement with high potential in accumulating in fatty tissues. However, challenges in extracting and characterizing RK and its associated phenolic compounds in fatty tissues persist due to the complex matrix effect. In this work, we reported a high-throughput sample preparation method for RK and 25 related phenolic compounds in white adipose tissues using an improved micro-scale QuEChERS (quick, efficient, cheap, easy, rugged and safe) approach with enhanced matrix removal (EMR)-lipid cleanup in 96-well plates, followed by UHPLC-QqQ-MS/MS analysis. The absolute recovery was 73-105% at the extraction step, and achieved 71-96% at the EMR cleanup step. The EMR cleanup removed around 66% of total lipids in the acetonitrile extract as profiled by UHPLC-QTOF-MS/MS. The innovative introduction of a reversed-phase C18 sorbent into the extract significantly improved the analytes' recovery during SpeedVac drying. The final accuracy achieved 80-120% for most analytes. Overall, this newly developed and validated method could serve as a powerful tool for analyzing RK and related phenolic compounds in fatty tissues.

Quality control of dietary supplements: An economic green spectrofluorimetric assay of Raspberry ketone and its application to weight variation testing

Although Dietary supplements are readily accessible and extensively used worldwide, they are inadequately regulated and consumers are victims of manufacturers' fraud. Thus, quality regulations are required to ensure safety of products available to the public. We propose the first native spectrofluorimetric quality control assay of raspberry ketone, a popular dietary supplement ingredient for weight loss. This work relies on the constant wavelength synchronous scan of the Raspberry Ketone native fluorescence, overcoming the demerits of conventional excitation/ emission spectra. For the best measurement conditions, several parameters were optimized including Δλ value, diluting solvent, medium pH and the effect of surfactants/ macromolecules. In aqueous medium (Δλ = 110 nm), a linear relationship exists between synchronous fluorescence intensity at peak maximum 405.6 nm and solution concentration in the range 300-1500 ng/mL. Method sensitivity was recorded with LOD and LOQ values 60.63 and 183.72 ng/mL; respectively. Validation was done in accordance to International Conference on Harmonization (ICH) guidelines. This simple procedure was successfully applied to the analysis of Raspberry Ketone in commercially available dietary supplement capsules with average recovery 98.67% ± 1.74 and further extended to weight variation testing following the official United States Pharmacopeial (USP) guidelines. Finally, green assessment was done using the ''Analytical Eco-scale'' tool. The total score was 89/100 points revealing excellent greenness of our proposal. Our proposal is simple, eco-friendly and cheap. It can be conveniently adopted for routine quality control practices especially in developing countries.

Pharmacological Exploration of Phenolic Compound: Raspberry Ketone-Update 2020

Raspberry ketone (RK) is an aromatic phenolic compound naturally occurring in red raspberries, kiwifruit, peaches, and apples and reported for its potential therapeutic and nutraceutical properties. Studies in cells and rodents have suggested an important role for RK in hepatic/cardio/gastric protection and as an anti-hyperlipidemic, anti-obesity, depigmentation, and sexual maturation agent. Raspberry ketone-mediated activation of peroxisome proliferator-activated receptor-α (PPAR-α) stands out as one of its main modes of action. Although rodent studies have demonstrated the efficacious effects of RK, its mechanism remains largely unknown. In spite of a lack of reliable human research, RK is marketed as a health supplement, at very high doses. In this review, we provide a compilation of scientific research that has been conducted so far, assessing the therapeutic properties of RK in several disease conditions as well as inspiring future research before RK can be considered safe and efficacious with limited side effects as an alternative to modern medicines in the treatment of major lifestyle-based diseases.

Acute feeding suppression and toxicity of raspberry ketone [4-(4-hydroxyphenyl)-2-butanone] in mice

Raspberry ketone (RK; [4-(4-hydroxyphenyl)-2-butanone]) is used by the food and cosmetic industry as a flavoring agent. RK is also marketed as a dietary supplement for weight maintenance and appetite control. The purpose of the study was to characterize the acute feeding suppression with RK (64-640 mg/kg) by oral gavage in male and female C57BL/6J mice. Cumulative 24 h food intake was reduced at 200 mg/kg (24% feeding suppression) in males and reliably reduced at 640 mg/kg (49-77% feeding suppression). Feeding suppression was not associated with pica behavior over the range of doses or conditioned taste aversion. In a separate experiment, a single oral gavage of RK (640 mg/kg) resulted in approximate 43% mortality rate (6 out 14 male mice) within 2 days. Atrophy of white adipose tissue, splenic abnormalities, and thymus involution were noted after 2-4 days after oral gavage RK. Total white blood cell count, lymphocytes, monocytes, eosinophils were significantly lower, while mean red blood cells, hemoglobin, and hematocrit were significantly higher with RK treatment. Our findings indicated a dose-dependent feeding suppression with acute RK, but doses that reliable suppress food intake are associated with pathological changes.

Raspberry Ketone [4-(4-Hydroxyphenyl)-2-Butanone] Differentially Effects Meal Patterns and Cardiovascular Parameters in Mice

Raspberry ketone (RK; [4-(4-hydroxyphenyl)-2-butanone]) is a popular nutraceutical used for weight management and appetite control. We sought to determine the physiological benefits of RK on the meal patterns and cardiovascular changes associated with an obesogenic diet. In addition, we explored whether the physiological benefits of RK promoted anxiety-related behaviors. Male and female C57BL/6J mice were administered a daily oral gavage of RK 200 mg/kg, RK 400 mg/kg, or vehicle for 14 days. Commencing with dosing, mice were placed on a high-fat diet (45% fat) or low-fat diet (10% fat). Our results indicated that RK 200 mg/kg had a differential influence on meal patterns in males and females. In contrast, RK 400 mg/kg reduced body weight gain, open-field total distance travelled, hemodynamic measures (i.e., reduced systolic blood pressure (BP), diastolic BP and mean BP), and increased nocturnal satiety ratios in males and females. In addition, RK 400 mg/kg increased neural activation in the nucleus of the solitary tract, compared with vehicle. RK actions were not influenced by diet, nor resulted in an anxiety-like phenotype. Our findings suggest that RK has dose-differential feeding and cardiovascular actions, which needs consideration as it is used as a nutraceutical for weight control for obesity.

UHPLC-QqQ-MS/MS method development and validation with statistical analysis: Determination of raspberry ketone metabolites in mice plasma and brain

Raspberry ketone (RK) (4-(4-hydroxyphenyl)-2-butanone) is the major compound responsible for the characteristic aroma of red raspberries, and has long been used commercially as a flavoring agent and recently as a weight loss supplement. A targeted UHPLC-QqQ-MS/MS method was developed and validated for analysis of RK and 25 associated metabolites in mouse plasma and brain. Dispersion and projection analysis and central composite design were used for method optimization. Random effect analysis of variance was applied for validation inference and variation partition. Within this framework, repeatability, a broader sense of precision, was calculated as fraction of accuracy variance, reflecting instrumental imprecision, compound degradation and carry-over effects. Multivariate correlation analysis and principle component analysis were conducted, revealing underlying association among the manifold of method traits. R programming was engaged in streamlined statistical analysis and data visualization. Two particular phenomena, the analytes' background existence in the enzyme solution used for phase II metabolites deconjugation, and the noted lability of analytes in pure solvent at 4 ℃ vs. elevated stability in biomatrices, were found critical to method development and validation. The approach for the method development and validation provided a foundation for experiments that examine RK metabolism and bioavailability.