Advancements and challenges in the bioproduction of raspberry ketone by precision fermentation

Raspberry ketone protects against isoproterenol-induced myocardial infarction in rats

Raspberry ketone loaded self nanoemulsifying system of cardamom oil: Assessment of phase behavior, dissolution rate and anti-hyperlipidemic activity

Raspberry ketone (RK), a natural product derived from raspberry fruit, is commonly utilized as a flavoring agent in foods and as an active component for weight loss. Metabolic engineering has enabled microorganisms to produce RK more efficiently and cost-effectively. However, the biosynthesis of RK is hindered by an unbalanced synthetic pathway and a deficiency of precursors, including tyrosine and malonyl-CoA. In this study, we constructed and optimized the RK synthetic pathway in Escherichia coli using a static metabolic engineering strategy to enhance the biosynthesis of tyrosine from glucose, thereby achieving the de novo production of RK. Additionally, the synthetic and consumption pathways of malonyl-CoA were dynamically regulated by p-coumaric acid-responsive biosensor to balance the metabolic flux distribution between cell growth and RK biosynthesis. Following pathway optimization, the medium components and fermentation conditions were further refined, resulting in a significant increase in the RK titer to 415.56 mg/L. The optimized strain demonstrated a 32.4-fold increase in the RK titer while maintaining a comparable final OD600 to the initial strain. Overall, the implemented static and dynamic regulatory strategies provide a novel approach for the efficient production of RK, taking into account cell viability and growth.

Mitochondrial dysfunction and oxidative stress play essential roles in the pathogenesis of diabetic nephropathy (DN). The respiratory oxygen consumption and oxidative stress status of kidney mitochondria are closely associated with the development of DN. In this study, raspberry ketone (RK), the predominant bioactive component extracted from raspberry, was applied to treat the established DN mice model. This study investigated whether RK protects the kidneys of high-fat and high-sugar/streptozotocin (STZ)-induced diabetic rats by inhibiting oxidative stress and ameliorating mitochondrial dysfunction. Besides, the DN mice models were established by injecting high-fat and high-sugar/STZ (130 mg/kg, intraperitoneal injection). The animals were randomly divided into the control group (normal saline, ig), DN group (normal saline, ig), DN + RK group (200 mg/kg RK + normal saline, ig), DN + RK group (400 mg/kg RK + normal saline, ig), and DN + Metformin (Met) (200 mg/kg Met + normal saline, ig). Regular monitoring of fasting blood glucose (FBG) levels was observed in mice. After 10 weeks of drug treatment, the kidneys of mice in each group were analyzed using ultrasound, and the mice were euthanized humanely. Kidney weight (KW)/body weight (BW) and kidney injury, mitochondrial function, and oxidative stress indicators were determined. The histopathological changes in renal tissue were observed after hematoxylin and eosin (H&E) staining. The results recommended that RK has a renoprotective function on DN mice by improving mitochondrial dysfunction and inhibiting oxidative stress.

Introduction:Clinical and epidemiological studies suggest that patients who are overweight or obese are more at risk in developing glucose intolerance (G/I) and insulin resistance (I/R) leading to type 2 diabetes (T2DM) and cardiovascular disease.Aim of work: Assess the dynamic contribution of visfatin in the development of obesity and/or diabetes and demonstrate their possible molecular mechanism(s) from side and from another side, modulate role of Raspberry ketone (RK) as weight management supplement and illustrate their possible molecular mechanism(s).Materials and Methods: Eighty adult rats were divided into eight groups (10 rats for each group, G); G1: Normal Control Group (Normal diet); G2: Diabetic Control Group (received streptozotocin 35 mg/kg); G3: Obese Control Group (received high fat diet, HFD); G4: Obese Diabetic Control Group, G5: Raspberry ketone Control Group (received 500 mg/kg), G6: Diabetic rats treated with Raspberry ketone; G7: Obese rats treated with Raspberry ketone and G8: Obese Diabetic rats treated with Raspberry ketone to assess the study's aims, their effect was determined on body weight, OGTT, glucose homeostasis (glucose, insulin, HOMA-IR), oxidative stress markers, cytoglobin, visfatin and liver histopathology.Results: RK caused weight loss, corrected the disturbed glucose and insulin homeostasis, Furthermore, RK increased hepatic content of glutathione (GSH), while decreased hepatic content of malonaldialdehyde (MDA).RK also up regulated hepatic protein expression of cytoglobin, while down regulated hepatic mRNA expression of visfatin.Conclusion: This study assessed the involvement of visfatin and cytoglobin in obese diabetic rats and modulated the role of RK through the efficient rebalance of glucose homeostasis, I/R, the redox status and liver histopathology.

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.

Raspberry ketone is a widely used flavor compound in food and cosmetic industry. Several processes for its biocatalytic production have already been described, but either with the use of genetically modified organisms (GMOs) or incomplete conversion of the variety of precursors that are available in nature. Such natural precursors are rhododendrol glycosides with different proportions of (R)- and (S)-rhododendrol depending on the origin. After hydrolysis of these rhododendrol glycosides, the formed rhododendrol enantiomers have to be oxidized to obtain the final product raspberry ketone. To be able to achieve a high conversion with different starting material, we assembled an alcohol dehydrogenase toolbox that can be accessed depending on the optical purity of the intermediate rhododendrol. This is demonstrated by converting racemic rhododendrol using a combination of (R)- and (S)-selective alcohol dehydrogenases together with a universal cofactor recycling system. Furthermore, we conducted a biocatalytic cascade reaction starting from naturally derived rhododendrol glycosides by the use of a glucosidase and an alcohol dehydrogenase to produce raspberry ketone in high yield.Key points• LB-ADH, LK-ADH and LS-ADH oxidize (R)-rhododendrol• RR-ADH and ADH1E oxidize (S)-rhododendrol• Raspberry ketone production via glucosidase and alcohol dehydrogenases from a toolboxGraphical abstract

Objective: Raspberry ketone (RK) is available as a supplement with effect on weight gain suppression. Recent studies have found that various herbal products can affect the activities of drug metabolizing enzymes and drug efflux proteins, and provoke clinically relevant drug-drug interactions. Capsaicin, a molecule having a similar chemical structure to RK, is another well-known cytochrome P450 (CYP) inhibitor. On the other hand, it is totally unclear whether RK has any effect on human CYP activities. In this study, we evaluated the effect of orally administered RK on CYP3A activity by measuring 6beta-hydroxycortisol/cortisol ratio in urine samples.

Bioconversion, i.e., the use of biological systems to perform chemical changes in synthetic or natural compounds in mild conditions, is an attractive tool for the production of novel active or high-value compounds. Plant cells exhibit a vast biochemical potential, being able to transform a range of substances, including pharmaceutical ingredients and industrial by-products, via enzymatic processes. The use of plant cell cultures offers possibilities for contained and optimized production processes which can be applied in industrial scale. Raspberry ketone [4-(4-hydroxyphenyl)butan-2-one] is among the most interesting natural flavor compounds, due to its high demand and significant market value. The biosynthesis of this industrially relevant flavor compound is relatively well characterized, involving the condensation of 4-coumaryl-CoA and malonyl-CoA by Type III polyketide synthase to form a diketide, and the subsequent reduction catalyzed by an NADPH-dependent reductase. Raspberry ketone has been successfully produced by bioconversion using different hosts and precursors to establish more efficient and economical processes. In this work, we studied the effect of overexpressed RiZS1 in tobacco on precursor bioconversion to raspberry ketone. In addition, various wild type plant cell cultures were studied for their capacity to carry out the bioconversion to raspberry ketone using either 4-hydroxybenzalacetone or betuligenol as a substrate. Apparently plant cells possess rather widely distributed reductase activity capable of performing the bioconversion to raspberry ketone using cheap and readily available precursors.

Annualy, helminthic diseases are one of the causes of economic losses in agriculture. Ruminantia are most often observed to be infected with nematodes of the gastrointestinal tract, including Strongyloides papillosus and the representatives of the Strongylida order. Identifying factors which could cause a decrease in the level of infection of agricultural animals with helminthiases would allow stock-raising facilities to regularly achieve high quality dairy and meat production in sufficient quantity. On the basis of this study, we determined the impact of flavourings and source materials approved for use in and on foods (isoamyl alcohol, isoamyl acetate, raspberry ketone, trilon B, methylparaben) on the survivability of larvae of Strongyloides papillosus and Haemonchus contortus, parasitic nematodes of Ruminantia animals. Among these substances, the lowest efficiency against the nematode larvae was found in isoamyl alcohol, isoamyl acetate and trilon B. A stronger effect was caused by methylparaben (for L3 S. papillosus LD50 = 0.67 ± 0.04%, L1 and L2 S. papillosus – LD50 = 0.0038 ± 0.0008%, L3 H. contortus – LD50 = 0.89 ± 0.15%). Minimum efficient dosage of the solutions was 10 g/l. Significant antihelminthic properties were manifested by raspberry ketone (for L3 S. papillosus LD50 = 1.00 ± 0.72%, L1 and L2 S. papillosus – LD50 = 0.07 ± 0.06%, L3 H. contortus – LD50 = 0.39 ± 0.26%). The results show that there is considerable potential for further studies on the antiparasitic properties of these substances against nematodes in the conditions of farming enterprises and agricultural complexes.

Preparations of the two closely-related natural products rheosmin (“raspberry ketone”, 4-(4′-hydroxyphenyl)-2-butanone) and zingerone (4-(4′-hydroxy-3′-methoxyphenyl)-2-butanone), are well-suited for the introductory organic laboratory. The crossed-aldol condensation of 4-hydroxybenzaldehyde with acetone gives an adduct (4-(4′-hydroxyphenyl)-3-buten-2-one) which is hydrogenated cleanly over rhodium on alumina to form rheosmin. Condensation of vanillin with acetone gives 4-(4′-hydroxy-3′-methoxyphenyl)-3-buten-2-one, which is hydrogenated to zingerone. The article includes background information on the target compounds and the synthetic methods used, along with experimental procedures and IR and NMR data on the compounds encountered.

Antibiotics and ibuprofen combinations cause mitochondrial toxicity and hepatotoxicity. This study investigated whether dietary antioxidants could protect against this damage via protein kinase AMP-activated alpha (AMPKα)/nuclear factor erythroid 2-related factor 2 (NRF2) pathways. Human umbilical vein endothelial cells (HUVECs) were treated with antibiotics (kanamycin, azithromycin, ampicillin or ciprofloxacin) plus ibuprofen with or without antioxidants. Azithromycin/ibuprofen induced hepatotoxicity was evaluated in C57BL/6J mice. Mitochondrial parameters including morphology, reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm) and key proteins (mitofusin 2, AMPKα, glycogen synthase kinase 3 beta [GSK3B], NRF2 and haem oxygenase 1 [HO1]) were analysed. Antibiotics/ibuprofen combinations triggered mitochondrial fission, ROS overproduction and mitofusin 2 down-regulation. Four antioxidants, that is, coniferaldehyde, raspberry ketone, gastrodin and eugenol, restored mitochondrial function and morphology. Coniferaldehyde and raspberry ketone effectively prevented in vivo hepatotoxicity and inflammation. Moreover, coniferaldehyde/raspberry ketone activated NRF2/HO1 while restoring AMPKα/GSK3B signalling. Coniferaldehyde and raspberry ketone showed potent rescue effects in vitro against all antibiotic models and in vivo against azithromycin/ibuprofen-induced hepatotoxicity through AMPKα-GSK3B/NRF2-HO1 modulation, with favourable safety profiles.

Preparations of the two closely-related natural products rheosmin (“raspberry ketone”, 4-(4′-hydroxyphenyl)-2-butanone) and zingerone (4-(4′-hydroxy-3′-methoxyphenyl)-2-butanone), are well-suited for the introductory organic laboratory. The crossed-aldol condensation of 4-hydroxybenzaldehyde with acetone gives an adduct (4-(4′-hydroxyphenyl)-3-buten-2-one), which is hydrogenated cleanly over rhodium on alumina to form rheosmin. Condensation of vanillin with acetone gives 4-(4′-hydroxy-3′-methoxyphenyl)-3-buten-2-one, which is hydrogenated to zingerone. The article includes background information on the target compounds and the synthetic methods used, along with experimental procedures and IR and NMR data on the compounds encountered.

The sterile insect technique (SIT) is a sustainable pest management tool based on the release of millions of sterile insects that suppress reproduction in targeted populations. Success of SIT depends on survival, maturation, dispersal, and mating of released sterile insects. Laboratory and field cage studies have demonstrated that dietary supplements of methoprene and raspberry ketone (RK) promote sexual maturation of adult Queensland fruit fly, Bactrocera tryoni (Froggatt), and may hence shorten the delay between release and maturity in the field. We investigated the effects of methoprene and RK dietary supplements on field abundance of sexually mature sterile Q-flies relative to untreated flies fed only sugar and yeast hydrolysate before release at 2 d of age. Compared with untreated flies, more methoprene- and RK-treated flies were recaptured in cuelure traps to which only sexually mature males are attracted. At distances of 100 and 200 m from the release point, recapture rates were higher for methoprene- and RK-treated flies than for untreated flies, but at 300 m recapture rates were low and were similar for treated and untreated flies. Rainfall, relative humidity, wind speed, and wind direction did not affect recapture rates, but temperature was positively correlated with recapture rates for all treatments. There was a strong correlation between the number of sterile and wild flies caught in traps, indicating co-location in the field. Dietary supplements of methoprene and RK can substantially increase abundance of sexually mature sterile male Q-flies in the field following release as 2-d-old immature adults.

Background: Raspberry ketone (RK), derived from red raspberry fruit (Rubus idaeus, family Rosaceae), is a reported potent antiobesity agent. This study aims to investigate method development, validation, and in vitro and in vivo pharmacokinetics in rats. Materials & methods: LC-MS/MS was used to conduct method development, validation, stability, and oral PK samples of RK in plasma analyses. Results: RK was highly soluble in Tris buffer and stable in gastrointestinal fluids as well as plasma. Rat liver microsomal stability of RK in phase I and II studies was 84.96±2.39 and 69.98±8.69%, respectively, after 60min. Intestinal permeability was 4.39±1.37×10-5cm/s. Maximal concentration was 1591.02±64.76ng/ml, which was achieved after 1h (time to maximal concentration), and absolute oral bioavailability was 86.28%. Conclusion: Pharmacokinetic data serve as a keystone for preclinical and clinical adjuvant therapy.