Protective effect of rosmarinic acid and carnosic acid against streptozotocin-induced oxidation, glycation, inflammation and microbiota imbalance in diabetic rats

Exploiting the beneficial effects of Salvia officinalis L. extracts in human health and assessing their activity as potent functional regulators of food microbiota

Salvia officinalis L. has attracted scientific and industrial interest due to its pharmacological properties. However, its detailed phytochemical profile and its correlation with beneficial effects in the human microbiome and oxidative stress remained elusive. To unveil this, S. officinalis was collected from the region of Epirus and its molecular identity was verified with DNA barcoding. Phytochemical profile for both aqueous and ethanol-based extracts was determined by high-pressure liquid chromatography-tandem mass spectrometry and 103 phytochemicals were determined. The effect of S. officinalis extracts as functional regulators of food microbiota by stimulating the growth of Lacticaseibacillus rhamnosus strains and by suppressing evolution of pathogenic bacteria was verified. Furthermore, we recorded that both extracts exhibited a significant cellular protection against H2O2-induced DNA damage. Finally, both extracts exhibited strong inhibitory effect towards LDL oxidation. This study provides a comprehensive characterization of S. officinalis on its phytochemical components as also its potential impact in human microbiome and oxidative stress.

Caffeic acid and ferulic acid can improve toxicological damage caused by iron overload mediated by carbonic anhydrase inhibition

The iron ion is an essential element for most forms of life, however, it can damage biological systems when found in free form. Chelation therapy is very important, but it is precarious. Caffeic and ferulic acid are antioxidant compounds with many properties described in research such as anti-inflammatory, antiobesogenic, antithrombotic, vasodilator, and anti-tumor. The aim of the study was to evaluate presenting an in silico approach on the toxicity and bioavailability of caffeic and ferulic acid, subsequently, evaluating them in an iron overload model in vivo and providing a pharmacophoric model through molecular docking. The predictive in silico test did not show relevant toxicity of the compounds, therefore, the in vivo test was performed. The rats received dextran iron and the test groups received caffeic and ferulic acid orally for six weeks. Biochemical, hematological parameters, and tissue oxidative stress marker were analyzed. The experimental model showed increased serum iron levels and changes in several serum parameters such as glucose (215.8 ± 20.3 mg/dL), ALT (512.2 ± 128.7 U/L), creatine kinase (186.8 ± 30.1 U/L), and creatine kinase isoform MB (373.3 ± 69.7 U/L). Caffeic acid and, to a lessed degree, ferullic acid, attenuated the effects of iron overload on the rat serum biochemical parameters. Docking showed a pharmacophoric model where carbonic anhydrase interacted with the test molecules and caffeic acid showed less energy expenditure in this interaction. The results illustrate a new therapeutic action of phenolic compounds on iron overload. The possible interference of carbonic anhydrase in iron metabolism needs to be elucidated.

The Effect of Rosmarinic Acid on Wound Healing of Nasal Mucosa in the Rats

BACKGROUND

The nose can be damaged by environmental pollutants and foreign bodies, as well as a result of trauma, infection or surgical interventions. Proper healing of the damaged nasal mucosa is important for health.

OBJECTIVE

There is no study in the literature investigating the effects of rosmarinic acid on mucosal healing. The aim of this study was to investigate the effect of rosmarinic acid on nasal mucosal healing.

METHODS

21 male, adult Spraque Dawley albino rats were divided into three groups as the control group, the local treatment group in which rosmarinic acid was applied locally to the nasal mucosa, and the systemic treatment group in which rosmarinic acid was injected intraperitoneally. The wound area was obtained by creating a trauma area by inserting a 10 mm interdental brush through the right nasal nostril into the right nasal cavities of all animals. For the following 15 days, the treatment agent was applied as indicated once a day and on the 15th day the animals were decapitated and tissue samples taken from the nasal mucosa were prepared for histopathological examination. The preparations were examined in terms of cellular hyperplasia, goblet cell hypertrophy and degeneration, leukocyte infiltration, cilia loss and degeneration, edema and vascular dilatation, and they have been classified into four categories as mild (+), moderate (++), severe (+++) and very severe (++++).

RESULTS

There was a significant difference between the groups in terms of all parameters evaluated, and there is a decrease in the intensity of the parameters with transition from the control group to the local group and from there to the systemic group.

CONCLUSION

Systemic rosmarinic acid administration showed an enhancing effect on the healing of experimentally induced nasal mucosal injury due to its possible anti-inflammatory effect.

Polyphenols Influence the Development of Endometrial Cancer by Modulating the Gut Microbiota

Dysbiosis of the microbiota in the gastrointestinal tract can induce the development of gynaecological tumours, particularly in postmenopausal women, by causing DNA damage and alterations in metabolite metabolism. Dysbiosis also complicates cancer treatment by influencing the body's immune response and disrupting the sensitivity to chemotherapy drugs. Therefore, it is crucial to maintain homeostasis in the gut microbiota through the effective use of food components that affect its structure. Recent studies have shown that polyphenols, which are likely to be the most important secondary metabolites produced by plants, exhibit prebiotic properties. They affect the structure of the gut microbiota and the synthesis of metabolites. In this review, we summarise the current state of knowledge, focusing on the impact of polyphenols on the development of gynaecological tumours, particularly endometrial cancer, and emphasising that polyphenol consumption leads to beneficial modifications in the structure of the gut microbiota.

Rosemary as a Potential Source of Natural Antioxidants and Anticancer Agents: A Molecular Docking Study

Rosmarinus officinalis L. compounds, especially its main polyphenolic compounds, carnosic acid (CA) and rosmarinic acid (RA), influence various facets of cancer biology, making them valuable assets in the ongoing fight against cancer. These two secondary metabolites exhibit formidable antioxidant properties that are a pivotal contributor against the development of cancer. Their antitumor effect has been related to diverse mechanisms. In the case of CA, it has the capacity to induce cell death of cancer cells through the rise in ROS levels within the cells, the inhibition of protein kinase AKT, the activation of autophagy-related genes (ATG) and the disrupt mitochondrial membrane potential. Regarding RA, its antitumor actions encompass apoptosis induction through caspase activation, the inhibition of cell proliferation by interrupting cell cycle progression and epigenetic regulation, antioxidative stress-induced DNA damage, and interference with angiogenesis to curtail tumor growth. To understand the molecular interaction between rosemary compounds (CA and RA) and a protein that is involved in cancer and inflammation, S100A8, we have performed a series of molecular docking analyses using the available three-dimensional structures (PDBID: 1IRJ, 1MR8, and 4GGF). The ligands showed different binding intensities in the active sites with the protein target molecules, except for CA with the 1MR8 protein.

Interactions between gut microbiota and polyphenols: A mechanistic and metabolomic review

BACKGROUND

Polyphenols are a class of naturally sourced compounds with widespread distribution and an extensive array of bioactivities. However, due to their complex constituents and weak absorption, a convincing explanation for their remarkable bioactivity remains elusive for a long time. In recent years, interaction with gut microbiota is hypothesized to be a reasonable explanation of the potential mechanisms for natural compounds especially polyphenols.

OBJECTIVES

This review aims to present a persuasive explanation for the contradiction between the limited bioavailability and the remarkable bioactivities of polyphenols by examining their interactions with gut microbiota.

METHODS

We assessed literatures published before April 10, 2023, from several databases, including Scopus, PubMed, Google Scholar, and Web of Science. The keywords used include "polyphenols", "gut microbiota", "short-chain fatty acids", "bile acids", "trimethylamine N-oxide", "lipopolysaccharides" "tryptophan", "dopamine", "intestinal barrier", "central nervous system", "lung", "anthocyanin", "proanthocyanidin", "baicalein", "caffeic acid", "curcumin", "epigallocatechin-3-gallate", "ferulic acid", "genistein", "kaempferol", "luteolin", "myricetin", "naringenin", "procyanidins", "protocatechuic acid", "pterostilbene", "quercetin", "resveratrol", etc. RESULTS: The review first demonstrates that polyphenols significantly alter gut microbiota diversity (α- and β-diversity) and the abundance of specific microorganisms. Polyphenols either promote or inhibit microorganisms, with various factors influencing their effects, such as dosage, treatment duration, and chemical structure of polyphenols. Furthermore, the review reveals that polyphenols regulate several gut microbiota metabolites, including short-chain fatty acids, dopamine, trimethylamine N-oxide, bile acids, and lipopolysaccharides. Polyphenols affect these metabolites by altering gut microbiota composition, modifying microbial enzyme activity, and other potential mechanisms. The changed microbial metabolites induced by polyphenols subsequently trigger host responses in various ways, such as acting as intestinal acid-base homeostasis regulators and activating on specific target receptors. Additionally, polyphenols are transformed into microbial derivatives by gut microbiota and these polyphenols' microbial derivatives have many potential advantages (e.g., increased bioactivity, improved absorption). Lastly, the review shows polyphenols maintain intestinal barrier, central nervous system, and lung function homeostasis by regulating gut microbiota.

CONCLUSION

The interaction between polyphenols and gut microbiota provides a credible explanation for the exceptional bioactivities of polyphenols. This review aids our understanding of the underlying mechanisms behind the bioactivity of polyphenols.

Kidney tea ameliorates hyperuricemia in mice via altering gut microbiota and restoring metabolic profile

Clerodendranthus spicatus (Thunb.) C. Y. Wu, also known as kidney tea (KT), has been widely employed in kidney protection in Chinese Medicine. It has been reported that KT can lower uric acid (UA) and mitigate gout, while the mechanism remains to be elucidated. Given the close relationship between hyperuricemia (HUA), intestinal flora and host metabolism, this study aimed to explore the mechanism by which KT lowers UA from the perspective of the fecal microbiome and metabolome. Initially, mice were intraperitoneally injected with potassium oxonate to induce the HUA model. The results showed that KT markedly reduced the serum level of UA and impaired renal damage in HUA mice. Subsequently, the result of 16S rRNA gene sequencing analysis indicated that KT administration appeared a significant improvement in the structure of the intestinal flora, especially increased the abundances of Roseburia and Enterorhabdus, while decreased the abundances of Ileibacterium and UBA1819. Moreover, the levels of differential metabolites (including twenty-five in feces and eight in serum) identified by untargeted metabolomics returned to normal after KT intervention. Taken together, the mechanism of KT in alleviating HUA is related to the regulation of the intestinal flora and the remodeling of metabolic disorders, which will lay a theoretical foundation for KT as a UA-lowering drug.

Phytotherapy of mood disorders in the light of microbiota-gut-brain axis

BACKGROUND

Clinical research in natural product-based psychopharmacology has revealed a variety of promising herbal medicines that may provide benefit in the treatment of mild mood disorders, however failed to unambiguously indicate pharmacologically active constituents. The emerging role of the microbiota-gut-brain axis opens new possibilities in the search for effective methods of treatment and prevention of mood disorders.

PURPOSE

Considering the clinically proven effectiveness juxtaposed with inconsistencies regarding the indication of active principles for many medicinal plants applied in the treatment of anxiety and depression, the aim of the review is to look at their therapeutic properties from the perspective of the microbiota-gut-brain axis.

METHOD

A literature-based survey was performed using Scopus, Pubmed, and Google Scholar databases. The current state of knowledge regarding Hypericum perforatum, Valeriana officinalis, Piper methysticum, Passiflora incarnata, Humulus lupulus, Melissa officinalis, Lavandula officinalis, and Rhodiola rosea in terms of their antimicrobial activity, bioavailability, clinical effectiveness in depression/anxiety and gut microbiota - natural products interaction was summarized and analyzed.

RESULTS

Recent studies have provided direct and indirect evidence that herbal extracts and isolated compounds are potent modulators of gut microbiota structure. Additionally, some of the formed postbiotic metabolites exert positive effects and ameliorate depression-related behaviors in animal models of mood disorders. The review underlines the gap in research on natural products - gut microbiota interaction in the context of mood disorders.

CONCLUSION

Modification of microbiota-gut-brain axis by natural products is a plausible explanation of their therapeutic properties. Future studies evaluating the effectiveness of herbal medicine and isolated compounds in treating mild mood disorders should consider the bidirectional interplay between phytoconstituents and the gut microbiota community.

Impact of the Extraction Method on the Chemical Composition and Antioxidant Potency of Rosmarinus officinalis L. Extracts

Rosmarinus officinalis L. is a dietary source that produces polyphenols as secondary metabolites. These natural compounds with potent antioxidant abilities are increasingly recommended as a supplement to inhibit oxidative stress. In the current work, we evaluated the impact of the extraction method on the chemical composition of R. officinalis extract, especially on the content of carnosic (CA) and rosmarinic (RA) acids using UPLC-MS-DAD as well as on their antioxidant potency. Four extracts of Tunisian rosemary were obtained from non-conventional extraction techniques:ultrasound-assisted extraction (UAE),supercritical extraction (SFE) and UAE and SFE combined ((UAE-SFE(I), UAE-SFE(II)). The UAE exhibited the best total phenolic compounds (i.e., 85.27 mg GAEg^-1), the highest content of CAand RA and the strongest antioxidant abilities (i.e., IC₅₀ = 0.13 mg/mL and EC₅₀ = 0.93 mg/mL for DPPH scavenging test and iron reducing power ability assay). The evaluation of antioxidant activity of UAE inhuman skin fibroblast (HS-68) cell line was carried out after the induction of oxidative stress. The results determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed a strong protective effect against H₂O₂oxidative stress induction in cells pretreated with UAE. The obtained results allow us to give new insight about the effect of the extraction method on the chemical composition and biological activities of the extract and the importance of the choice of the most appropriate processing technique to prepare rosemary extract with a high antioxidant potency and protective effect against oxidative stress.

Anti-Inflammatory Therapeutic Mechanisms of Natural Products: Insight from Rosemary Diterpenes, Carnosic Acid and Carnosol

Carnosic acid (CA) and carnosol (CAR) are two major diterpenes of the rosemary plant (Rosmarinus officinalis). They possess a phenolic structural moiety and are endowed with the power to remove cellular reactive oxygen species (ROS) either through direct scavenging reaction or indirectly through upregulation of antioxidant defences. Hand in hand with these activities are their multiple biological effects and therapeutic potential orchestrated through modulating various signalling pathways of inflammation, including the NF-κB, MAPK, Nrf2, SIRT1, STAT3 and NLRP3 inflammasomes, among others. Consequently, they ameliorate the expression of pro-inflammatory cytokines (e.g., TNF-α, IL-1 and IL-6), adhesion molecules, chemokines and prostaglandins. These anti-inflammatory mechanisms of action as a therapeutic link to various effects of these compounds, as in many other natural products, are scrutinised.

The Impact of Za'atar Antioxidant Compounds on the Gut Microbiota and Gastrointestinal Disorders: Insights for Future Clinical Applications

Since the gut microbiota plays a pivotal role in host homeostasis and energy balance, changes in its composition can be associated with disease states through the promotion of immune-mediated inflammatory disorders and increasing intestinal permeability, ultimately leading to the impairment of intestinal barrier function. Za'atar is one of the most popular plant-based foods in the Eastern Mediterranean region. Za'atar is a mixture of different plant leaves, fruits, and seeds and contains hundreds of antioxidant compounds, especially polyphenols, and fiber, with pre-clinical and clinical evidence suggesting health-promoting effects in cardiovascular and metabolic disease. Za'atar compounds have also been studied from a gastrointestinal perspective, concerning both gut microbiota and gastrointestinal diseases. Antioxidants such as Za'atar polyphenols may provide beneficial effects in the complex interplay between the diet, gut microbiota, and intestinal permeability. To our knowledge, no studies have reported the effects of the whole Za'atar mixture, however, based on the pre-clinical studies published on components and single compounds found in Za'atar, we provide a clinical overview of the possible effects on the gastrointestinal tract, focusing mainly on carvacrol, rosmarinic acid, gallic acid, and other polyphenols. We also cover the potential clinical applications of Za'atar mixture as a possible nutraceutical in disorders involving the gastrointestinal tract.

Neuroprotective Effect of Ponicidin Alleviating the Diabetic Cognitive Impairment: Regulation of Gut Microbiota

Cognitive impairment is a major complication of diabetes mellitus, which is caused by constitutive hyperglycaemia. Ponicidin is a diterpenoid isolated from a Chinese traditional herb (Rabdosia rubescens) and demonstrates the various pharmacological effects. The goal of this study was to scrutinise the neuroprotective effect of ponicidin against diabetic nephropathy (DN) induced by streptozotocin (STZ). Intraperitoneal administration of STZ (55 mg/kg) was used for the induction of diabetes and rats were received oral administration of ponicidin (5, 10 and 15 mg/kg) until 28 days. The body weight, food intake, water intake and blood glucose level were assessed at regular time interval. Plasma insulin level, antioxidant, inflammatory cytokines, apoptosis marker and faecal gut microbiota compositions were estimated. DN-induced group rats revealed the augmented glucose level, water intake, food intake and reduced body weight. Ponicidin significantly (P < 0.001) repressed the glucose level and water food intake and improved the body weight and plasma insulin. Ponicidin significantly (P < 0.001) repressed the malonaldehyde (MDA) level and boosted the level of glutathione (GSH), glutathione reductase (GR) and superoxide dismutase (SOD) in the brain and serum level. Ponicidin significantly (P < 0.001) repressed the level of interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and enhanced the level of interleukin-4 (IL-4), interleukin-10 (IL-10) in the brain and serum level. DN group rats exhibited the enhanced relative abundance of Firmicutes, along with enhancing the Firmicutes/Bacteroidetes ratio and repressing the Bacteroidetes relative abundance. Ponicidin effectually restored the relative abundance of Allobaculum, Lactobacillus and Ruminococcus genera. Our findings clearly demonstrated that ponicidin has a neuroprotective effect against diabetic cognitive impairment through modulating the gut microbiome.

Dietary phytochemical and metabolic disease prevention: Focus on plant proteins

Plant-based functional foods have attracted increasing research interest to validate their use in preventing metabolic disease. Since it is increasingly recognized that inflammation, oxidative stress, and circadian rhythm play vital roles in various metabolic diseases, including diabetes, obesity and non-alcoholic liver disease, plant proteins, protein hydrolysates, and food extracts that intervene in these biological processes are promising dietary supplements to prevent metabolic diseases. Here, we reviewed the recent research on plant-based foods used for metabolic disease prevention and provided new perspectives regarding the current study gaps and future directions in this field.

New Molecules of Diterpene Origin with Inhibitory Properties toward α-Glucosidase

The incidence of diabetes mellitus (DM), one of the most common chronic metabolic disorders, has increased dramatically over the past decade and has resulted in higher rates of morbidity and mortality worldwide. The enzyme, α-Glucosidase (α-GLy), is considered a therapeutic target for the treatment of type 2 DM. Herein, we synthesized arylidene, heterocyclic, cyanoetoxy- and propargylated derivatives of quinopimaric acid (levopimaric acid diene adduct with p-benzoquinone) 1-50 and, first, evaluated their ability to inhibit α-GLy. Among the tested compounds, quinopimaric acid 1, 2,3-dihydroquinopimaric acid 8 and its amide and heterocyclic derivatives 9, 30, 33, 39, 44, with IC50 values of 35.57-65.98 μM, emerged as being good inhibitors of α-GLy. Arylidene 1β-hydroxy and 1β,13α-epoxy methyl dihydroquinopimarate derivatives 6, 7, 26-29, thiadiazole 32, 1a,4a-dehydroquinopimaric acid 40 and its indole, nitrile and propargyl hybrids 35-38, 42, 45, 48, and 50 showed excellent inhibitory activities. The most active compounds 38, 45, 48, and 50 displayed IC50 values of 0.15 to 0.68 μM, being 1206 to 266 more active than acarbose (IC50 of 181.02 μM). Kinetic analysis revealed the most active diterpene indole with an alkyne substituent 45 as a competitive inhibitor with Ki of 50.45 μM. Molecular modeling supported this finding and suggested that the indole core plays a key role in the binding. Compound 45 also has favorable pharmacokinetic and safety properties, according to the computational ADMET profiling. The results suggested that quinopimaric acid derivatives should be considered as potential candidates for novel alternative therapies in the treatment of type 2 diabetes.

Anti-diabetic and gut microbiota modulation effects of sacha inchi (Plukenetia volubilis L.) leaf extract in streptozotocin-induced type 1 diabetic mice

BACKGROUND

Sacha inchi (Plukenetia volubilis L.) tea has been used as an adjuvant treatment for diabetes in Pu'er, in the Yunnan province of China. The effects of sacha inchi tea on diabetes and the underlying mechanisms remain unknown. This study was conducted to investigate the influence of a water extract of sacha inchi (P. volubilis L.) leaves (PWE) on hypoglycemic activity and gut microbiota composition in mice with streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM). During the 6 weeks of the study, T1DM mice were administered PWE intragastrically at 400 mg kg^-1 body weight (BW) per day.

RESULTS

Treatment with PWE reduced excessive loss of BW and excessive intake of food. It significantly decreased blood glucose levels and improved oral glucose tolerance. The treatment caused protective histopathological transformations in sections of the pancreas, leading to decreased insulin resistance and improved insulin sensitivity. Treatment with PWE also significantly ameliorated disorders of the gut microbiota structure and increased the richness and diversity of intestinal microbial species in T1DM mice. At the genus level, the populations of several crucial bacteria, such as Akkermansia, Parabacteroides, and Muribaculum increased in the PWE treatment group but the abundance of Ruminiclostridium and Oscillibacter decreased.

CONCLUSIONS

Treatment with PWE can ameliorate hyperglycemic symptoms in STZ-induced T1DM mice, and the anti-diabetic effect of PWE was related to the amelioration of gut microbial structural disorder and the enrichment of functional bacteria. © 2022 Society of Chemical Industry.

Food Additives Associated with Gut Microbiota Alterations in Inflammatory Bowel Disease: Friends or Enemies?

During the 21st century, the incidence and prevalence of inflammatory bowel disease (IBD) is rising globally. Despite the pathogenesis of IBD remaining largely unclear, the interactions between environmental exposure, host genetics and immune response contribute to the occurrence and development of this disease. Growing evidence implicates that food additives might be closely related to IBD, but the involved molecular mechanisms are still poorly understood. Food additives may be categorized as distinct types in accordance with their function and property, including artificial sweeteners, preservatives, food colorant, emulsifiers, stabilizers, thickeners and so on. Various kinds of food additives play a role in modifying the interaction between gut microbiota and intestinal inflammation. Therefore, this review comprehensively synthesizes the current evidence on the interplay between different food additives and gut microbiome alterations, and further elucidates the potential mechanisms of food additives–associated microbiota changes involved in IBD.

Rosmarinic acid ameliorated psoriatic skin inflammation in mice through the novel inhibition of the interleukin-17A/interleukin-17A receptor interaction

The interaction between interleukin-17A (IL-17A) and IL-17A receptor (IL-17RA) is a crucial target of psoriasis. Several natural compounds from foods or herbs have displayed efficacies on the amelioration of psoriasis. However, the anti-psoriatic mechanisms are mostly through the common anti-inflammatory effects and rarely via the blockage of the IL-17A/IL-17RA interaction. In this study, the IL-17A/IL-17RA-targeting effects of phenylpropanoids, a large class of secondary metabolites in plants, were analyzed. By screening 17 phenylpropanoids, we found that top four compounds with IL-17A/IL-17RA-blocking abilities were rosmarinic acid, eugenol, syringic acid, and gallic acid, with inhibitory concentrations at 50% of 2.14 ± 0.35 mM, 6.35 ± 0.1 mM, 4.79 ± 0.2 mM, and >10 mM, respectively. The oral administration of rosmarinic acid ameliorated redness and scaling on the dorsal skin of imiquimod-induced psoriatic mice in a dose-dependent manner. Rosmarinic acid suppressed the production of IL-23 and IL-17A and the infiltration of granulocyte subsets in skin tissues. Docking analysis showed that rosmarinic acid docked into IL-17A/IL-17RA interaction regions and exhibited hydrogen bonding with Arg-61, Glu-68, Arg-100, and Ser-118 of IL-17A, which are located in the epitope regions recognized by IL-17A neutralizing antibodies Fab6785 and Fab6468. In conclusion, this is the first study reporting that rosmarinic acid is an IL-17A-targeting agent that ameliorates psoriatic skin inflammation in mice via blocking the IL-17A/IL-17RA interaction.

Metabolic Engineering of Saccharomyces cerevisiae for Heterologous Carnosic Acid Production

Carnosic acid (CA), a phenolic tricyclic diterpene, has many biological effects, including anti-inflammatory, anticancer, antiobesity, and antidiabetic activities. In this study, an efficient biosynthetic pathway was constructed to produce CA in Saccharomyces cerevisiae. First, the CA precursor miltiradiene was synthesized, after which the CA production strain was constructed by integrating the genes encoding cytochrome P450 enzymes (P450s) and cytochrome P450 reductase (CPR) SmCPR. The CA titer was further increased by the coexpression of CYP76AH1 and SmCPR ∼t28SpCytb5 fusion proteins and the overexpression of different catalases to detoxify the hydrogen peroxide (H₂O₂). Finally, engineering of the endoplasmic reticulum and cofactor supply increased the CA titer to 24.65 mg/L in shake flasks and 75.18 mg/L in 5 L fed-batch fermentation. This study demonstrates that the ability of engineered yeast cells to synthesize CA can be improved through metabolic engineering and synthetic biology strategies, providing a theoretical basis for microbial synthesis of other diterpenoids.

Biomedical features and therapeutic potential of rosmarinic acid

For decades, the use of secondary metabolites of various herbs has been an attractive strategy in combating human diseases. Rosmarinic acid (RA) is a bioactive phenolic compound commonly found in plants of Lamiaceae and Boraginaceae families. RA is biosynthesized using amino acids tyrosine and phenylalanine via enzyme-catalyzed reactions. However, the chemical synthesis of RA involves an esterification reaction between caffeic acid and 3,4-dihydroxy phenyl lactic acid contributing two phenolic rings to the structure of RA. Several studies have ascertained multiple therapeutic benefits of RA in various diseases, including cancer, diabetes, inflammatory disorders, neurodegenerative disorders, and liver diseases. Many previous scientific papers indicate that RA can be used as an anti-plasmodic, anti-viral and anti-bacterial drug. In addition, due to its high anti-oxidant capacity, this natural polyphenol has recently gained attention for its possible application as a nutraceutical compound in the food industry. Here we provide state-of-the-art, flexible therapeutic potential and biomedical features of RA, its implications and multiple uses. Along with various valuable applications in safeguarding human health, this review further summarizes the therapeutic advantages of RA in various human diseases, including cancer, diabetes, neurodegenerative diseases. Furthermore, the challenges associated with the clinical applicability of RA have also been discussed.

Carnosic Acid Protects INS-1 β-Cells against Streptozotocin-Induced Damage by Inhibiting Apoptosis and Improving Insulin Secretion and Glucose Uptake

Carnosic acid (CA), a natural polyphenolic diterpene derived from Rosmarinus officinalis, has been proven to possess a broad spectrum of medicinal properties. Nevertheless, no studies on its impact on pancreatic β-cells have been conducted to date. Herein, clonal rat INS-1 (832/13) cells were pretreated with CA for 24 h and then incubated with streptozotocin (STZ) for 3 h. Several functional experiments were performed to determine the effect of CA on STZ-induced pancreatic β-cell damage, including cell viability assay, apoptosis analysis, and measurement of the level of insulin secretion, glucose uptake, malondialdehyde (MDA), reactive oxygen species (ROS), and proteins expression. STZ treatment decreased cell survival, insulin secretion, glucose uptake, and increased apoptosis, MDA, and ROS production in INS-1 cells. Furthermore, protein expression/phosphorylation analysis showed significant down-regulation in insulin, PDX-1, PI3K, AKT/p-AKT, and Bcl₂. On the other hand, expression of BAX and BAD and cleaved PARP were significantly increased. Interestingly, preincubation with CA reversed the adverse impact of STZ at the cellular and protein expression levels. In conclusion, the data indicate that CA protects β-cells against STZ-induced damage, presumably through its modulatory effect on the different pathways, including the Pi3K/AKT/PDX-1/insulin pathway and mitochondria-mediated apoptosis.

Potential of Diterpenes as Antidiabetic Agents: Evidence from Clinical and Pre-Clinical Studies

Diterpenes are a diverse group of structurally complex natural products with a wide spectrum of biological activities, including antidiabetic potential. In the last 25 years, numerous diterpenes have been investigated for antidiabetic activity, with some of them reaching the stage of clinical trials. However, these studies have not been comprehensively reviewed in any previous publication. Herein, we critically discussed the literature on the potential of diterpenes as antidiabetic agents, published from 1995 to September, 2021. In the period under review, 427 diterpenes were reported to have varying degrees of antidiabetic activity. Steviol glycosides, stevioside (1) and rebaudioside A (2), were the most investigated diterpenes with promising antidiabetic property using in vitro and in vivo models, as well as human subjects. All the tested pimaranes consistently showed good activity in preclinical evaluations against diabetes. Inhibitions of α-glucosidase and protein tyrosine phosphatase 1B (PTP 1B) activities and peroxisome proliferator-activated receptors gamma (PPAR-γ) agonistic property, were the most frequently used assays for studying the antidiabetic activity of diterpenes. The molecular mechanisms of action of the diterpenes include increased GLUT4 translocation, and activation of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK)-dependent signaling pathways. Our data revealed that diterpenes hold promising antidiabetic potential. Stevioside (1) and rebaudioside A (2) are the only diterpenes that were advanced to the clinical trial stage of the drug discovery pipeline. Diterpenes belonging to the abietane, labdane, pimarane and kaurane class have shown promising activity in in vitro and in vivo models of diabetes and should be further investigated.

Identification of adducts between oxidized rosmarinic acid and glutathione compounds by electrochemistry, liquid chromatography and mass spectrometry

Natural polyphenols are omnipresent and are an integral part of the human diet as well as quinones. Glutathione (GSH) is present in a significant amount inside cells and consequently, GSH conjugates of polyphenols will be encountered in the body. In the current work, voltammetry and liquid chromatography-mass spectrometry were carried out to characterize the reaction mechanism of the electrochemical oxidation of polyphenolic rosmarinic acid (RA) with GSH nucleophiles in aqueous solution. Electrochemical investigation of RA revealed that two consecutive transfer steps (which depend on pH) of two electrons and protons occur during the reversible oxidation of RA. Moreover, it was found that the first oxidation step is associated with the 3,4-dihydroxyphenyl lactic acid moiety, whereas the second oxidation step corresponds to the oxidation of the caffeic acid one. By using ultrahigh-performance liquid chromatography-diode array detection-mass spectrometry (UPLC-DAD-MS) in the negative ion mode, the oxidation pathways of RA in the presence of GSH were analyzed, and a total of four RA-GSH conjugates were identified. The oxidative degradation pathway of RA can be better apprehended and forecasted by the acquired results in this study.

A Systematic Review of Orthosiphon stamineus Benth. in the Treatment of Diabetes and Its Complications

(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.

Carnosic Acid Attenuates the Free Fatty Acid-Induced Insulin Resistance in Muscle Cells and Adipocytes

Elevated blood free fatty acids (FFAs), as seen in obesity, impair insulin action leading to insulin resistance and Type 2 diabetes mellitus. Several serine/threonine kinases including JNK, mTOR, and p70 S6K cause serine phosphorylation of the insulin receptor substrate (IRS) and have been implicated in insulin resistance. Activation of AMP-activated protein kinase (AMPK) increases glucose uptake, and in recent years, AMPK has been viewed as an important target to counteract insulin resistance. We reported previously that carnosic acid (CA) found in rosemary extract (RE) and RE increased glucose uptake and activated AMPK in muscle cells. In the present study, we examined the effects of CA on palmitate-induced insulin-resistant L6 myotubes and 3T3L1 adipocytes. Exposure of cells to palmitate reduced the insulin-stimulated glucose uptake, GLUT4 transporter levels on the plasma membrane, and Akt activation. Importantly, CA attenuated the deleterious effect of palmitate and restored the insulin-stimulated glucose uptake, the activation of Akt, and GLUT4 levels. Additionally, CA markedly attenuated the palmitate-induced phosphorylation/activation of JNK, mTOR, and p70S6K and activated AMPK. Our data indicate that CA has the potential to counteract the palmitate-induced muscle and fat cell insulin resistance.

Absorption and Transport Characteristics and Mechanisms of Carnosic Acid

Simple Summary

Carnosic acid (CA), a phenolic diterpenoid mainly found in rosemary and sage, has been reported to possess various health-beneficial activities. However, detailed information about the absorption characteristics and mechanisms of CA and its tissue distribution still remains unclear. It has been well-recognized that the absorption, transport, and metabolism of dietary bioactive compounds are closely related to their biological functions. Herein, a mouse study and Caco-2 cell monolayer model of the intestinal epithelial barrier were used to understand the absorption and transport characteristics of CA. First, we determined the tissue distribution of CA in mice following oral gavage at a physiologically relevant dose. We found that CA was bioavailable systemically and present locally in the digestive tract, especially in the cecum and colon. Next, in Caco-2 cell monolayers, CA exhibited a moderate permeability and was subjected to mild efflux. Moreover, the apparent permeability coefficient of CA transported across Caco-2 cell monolayers was significantly changed when the inhibitors of specific active transporter and passive diffusion were added, suggesting that the absorption and transport of CA involved both passive and active transportation. The present study is an important first step towards understanding the absorption, transport, and metabolic mechanisms of CA.

Abstract

Carnosic acid (CA) is a phenolic diterpenoid mainly found in rosemary and sage. CA has been reported to possess health-beneficial effects in various experimental settings. Herein, a mouse experiment and Caco-2 single-cell model were used to understand the absorption and transport characteristics of CA. First, we determined the tissue distribution of CA in mice, following an oral gavage at a physiologically relevant dose. We found that CA was bioavailable systemically and present locally in the digestive tract, especially in the cecum and colon. Next, we thought to characterize the absorption and transport of CA in the Caco-2 cell monolayer model of the intestinal epithelial barrier. In the Caco-2 cell model, CA exhibited a moderate permeability and was subjected to a mild efflux. Moreover, the apparent permeability coefficient (P_app) of CA transported across Caco-2 cell monolayers was significantly changed when the inhibitors of specific active transporter and passive diffusion were added to cells, suggesting that the absorption and transport of CA involved both passive and active transportation. The present study is an important first step towards understanding the absorption, transport, and metabolic mechanisms of CA. This could provide the scientific basis for developing CA-containing functional foods or dietary supplements with improved bioavailability.

Rosmarinic acid inhibits DNA glycation and modulates the expression of Akt1 and Akt3 partially in the hippocampus of diabetic rats

Non-enzymatic glycation of DNA and the associated effects are among pathogenic factors in diabetes mellitus. Natural polyphenols have anti-diabetic activity. Herein, the protective role of one of the phytochemicals, rosmarinic acid (RA), was evaluated in glycation (with fructose) of human DNA and expression of Akt genes in the hippocampus of diabetic rats. In-vitro studies using fluorescence, agarose gel electrophoresis, fluorescence microscopy, and thermal denaturation analyses revealed that glycation causes DNA damage and that RA inhibits it. In-vivo studies were performed by induction of diabetes in rats using streptozotocin. The diabetic rats were given RA daily through gavage feeding. The expression of Akt genes (inhibitors of apoptosis) in the hippocampus was evaluated using RT-qPCR. In diabetic rats, Akt1 and Akt3 were significantly down-regulated compared to the control group. Treating the diabetic rats with RA returned the expression of Akt1 and Akt3 relatively to the normal condition. Past studies have shown that diabetes induces apoptosis in the hippocampal neurons. Given that glycation changes the genes expression and causes cell death, apoptosis of the hippocampal neurons can be due to the glycation of DNA. The results also suggest that RA has reliable potency against the gross modification of DNA under hyperglycemic conditions.

Improving in vitro bioaccessibility and bioactivity of carnosic acid using a lecithin-based nanoemulsion system

As a phenolic terpenoid, carnosic acid (CA) mainly exists in rosemary, which can be effectively used for the treatment of degenerative and chronic diseases by taking advantage of its health-promoting bioactivities. However, the low solubility and dissolution of CA in aqueous solutions at ambient and body temperatures result in low stability and bioaccessibility during the digestion process, which limits its application scope in the functional foods industry. In this regard, a lecithin based nanoemulsion system (CA-NE) is employed in the present work to enhance the bioaccessibility and bioactivities of CA. It is revealed that the CA-NE under investigation exhibits high loading capacity (2.80 ± 0.15%), small particle size (172.0 ± 3.5 nm) with homogeneous particle distribution (polydispersity index (PDI) of 0.231± 0.025) and high repulsive force (zeta potential = -57.2 ± 0.24 mV). More importantly, the bioaccessibility of CA-NE is improved by 2.8-fold compared to that of CA in MCT oil. In addition, the cellular antioxidant assay (CAA) and cellular uptake study of the CA-NE in HepG2 cell models demonstrate a longer endocytosis process, suggesting the well-controlled release of CA from CA-NE. Furthermore, an improved anti-inflammatory activity was evaluated via the inhibition of the pro-inflammatory cytokines, nitric oxide (NO) and TNF-α production in LPS-stimulated RAW 264.7 macrophage cells. The results clearly demonstrated a promising application of CA-NE as a functional food.

Polyphenolic and molecular variation in Thymus species using HPLC and SRAP analyses

In the present research, inter and intra genetic variability of 77 accessions belonging to 11 Thymus species were assessed using eight SRAP primer combinations. High polymorphism (98.3%) was observed in the studied species. The cluster analysis classified Thymus species into five main groups. According to molecular variance (AMOVA) analysis, 63.14% of total genetic variation was obtained within the species, while 36.86% of variation was observed among species. STRUCTURE analysis was also performed to estimate the admixture of species. For instance, T. carmanicus and T. transcaspicus revealed high admixtures. HPLC analysis also demonstrated the presence of rosmarinic acid (32.3–150.7 mg/100 g DW), salvianolic acid (8–90 mg/100 g DW), and cinnamic acid (1.7–32.3 mg/100 g DW) as major phenolic acids, as well as apigenin, epicatechin, and naringenin as the major flavonoids. The highest phenolic and flavonoid contents were detected in T. transcaspicus (37.62 mg gallic acid equivalents (GAE) g⁻¹ DW) and T. vulgaris (8.72 mg quercetin equivalents (QE) g⁻¹ DW), respectively. The antioxidant properties and total phenolic of Thymus species were examined using DPPH and β-carotene-linoleic acid model systems and consequently T. vulgaris and T. pubescens were detected with the highest and the lowest antioxidant activities respectively. Cluster and principal Components Analysis (PCA) of the components classified the species in to three groups. Finally, similarity within some species was observed comparing molecular and phytochemical markers. For instance, T. vulgaris separated from other species according to major polyphenolic profiles and molecular analyses, as well as T. transcaspicus, T. carmanicus, and T. fedtschenkoi that were clustered in the same groups.

Amelioration of oxidative stress and neuroinflammation in lipopolysaccharide-induced memory impairment using Rosmarinic acid in mice

Oxidative stress plays a pivotal part in the manifestation of neuroinflammation, which further leads to neurodegenerative diseases like Alzheimer's disease (AD). Systemic administration of lipopolysaccharide (LPS) induces neuroinflammation resulting in memory impairment (MI) and cognitive decline. In this study, we evaluated whether prophylactic administration of Rosmarinic acid (RA), a naturally occurring compound, exerts a neuroprotective effect in LPS-induced MI and cognitive decline. Herein, Swiss albino mice were pre-treated with RA (0.5 mg/kg and 1 mg/kg i.p.) for 28 days and were intermittently exposed to LPS (0.25 mg/kg i.p.) for 7 days. LPS caused poor memory retention and increased cognitive decline in Morris water maze (MWM) and Y maze paradigms respectively. Additionally, LPS increased oxidative stress which was denoted by a decrease in superoxide dismutase (SOD) activity, decrease in reduced glutathione (GSH) levels, and increased lipid peroxidation in the brain. Imbalance in the cholinergic system was analyzed by measuring the acetylcholinesterase (AChE) activity. Pre-treatment with RA improved memory and behavioral disturbances by alleviating oxidative stress and AChE activity. LPS augmented levels of tumor necrosis factor (TNF-α), interleukin (IL)-6, caspase-3, and c-Jun. Pre-treatment with RA revitalized the elevated levels of proinflammatory cytokines and apoptotic proteins. In conclusion, this study showcases the amelioration of MI by RA in LPS-challenged memory and cognitive decline, which could be credited to its anti-oxidant effect, inhibitory effect on both proinflammatory cytokines and apoptotic regulators, and reduction in AChE activity.

Rosemary extract activates AMPK, inhibits mTOR and attenuates the high glucose and high insulin-induced muscle cell insulin resistance

Impaired action of insulin in skeletal muscle, termed insulin resistance, leads to increased blood glucose levels resulting in compensatory increase in insulin levels. The elevated blood glucose and insulin levels exacerbate insulin resistance and contribute to the pathogenesis of type 2 diabetes mellitus. In previous studies we found attenuation of free fatty acid-induced muscle cell insulin resistance by rosemary extract (RE). In the present study we investigated the effects of RE on high glucose (HG) and high insulin (HI)-induced muscle cell insulin resistance. Exposure of L6 myotubes to 25 mmol/L glucose and 100 nmol/L insulin for 24 h, to mimic hyperglycemia and hyperinsulinemia, abolished the acute insulin-stimulated glucose uptake, increased the serine phosphorylation of IRS-1 and the phosphorylation/activation of mTOR and p70S6K. Treatment with RE significantly improved the insulin-stimulated glucose uptake and increased the acute insulin-stimulated tyrosine phosphorylation while reducing the HG+HI-induced serine phosphorylation of IRS-1 and phosphorylation of mTOR and p70S6K. Additionally, treatment with RE significantly increased the phosphorylation of AMPK, its downstream effector ACC and the plasma membrane GLUT4 levels. Our data indicate a potential of RE to counteract muscle cell insulin resistance and more studies are required to investigate its effectiveness in vivo. Novelty: RE phosphorylated muscle cell AMPK and ACC under both normal and HG+HI conditions. The HG+HI-induced serine phosphorylation of IRS-1 and activation of mTOR and p70S6K were attenuated by RE. RE restored the insulin-stimulated glucose uptake by enhancing GLUT4 glucose transporter translocation to plasma membrane.

Abietane Diterpenes as Potential Candidates for the Management of Type 2 Diabetes

Diabetes mellitus (DM) is considered one of the most common metabolic disorders with an elevated morbidity and mortality rate. It is characterised by a deficiency in insulin secretion or degradation of secreted insulin. Many internal and external factors, such as oxidative stress, obesity and sedentary lifestyle, among others, have been suggested as the major causes of these cell alterations. Diabetes I and II are the most common types of diabetes. Treatment of type I requires insulin injection, while type II can be managed using different synthetic antidiabetic agents. However, their effectiveness is limited as a result of low bioavailability, high cost of drug production, and unfavourable side effects. There is a great need to develop alternative and more active antidiabetic drugs from natural sources. Different forms of natural products have been used since time immemorial as a source of medicine for the purpose of curing numerous human diseases, including diabetes. Secondary metabolites such as polyphenols, flavonoids, terpenoids, alkaloids and several other constituents have direct and indirect roles in controlling such diseases; among them, abietane diterpenes have been reported to display a broad spectrum of promising biological activities including diabetes. This review aimed to summarize existing data from SciFinder (2005-2018) on the biological importance of abietane diterpenes in the prevention and management of type 2 diabetes and closely related diseases.

Rosemary Leaf Extract Inhibits Glycation, Breast Cancer Proliferation, and Diabetes Risks

Advanced glycation end products (AGEs) generated from glycation can cause inflammation-related diseases such as diabetes and cancer. The bioactive compounds of rosemary extract (RE) were extracted and incubated with sugar-protein rich food and breast cancer cell MCF-7 to investigate its inhibitory effect on glycation and cancer cell proliferation, respectively. The diabetic rat was dosed with RE to investigate its effect on blood glucose, serum malondialdehyde (MDA), cholesterol (CHO), triglycerides (TG), low-density lipoproteins (LDLs), anti-oxidation capacity (T-AOC), superoxide dismutase (SOD) activity, anti-oxidation capacity alkaline phosphatase (ALP), glutamate pyruvate transaminase (GPT), and glutamate oxaloacetate transaminase (GOT). The results show that RE contained seven major phenolics ranging from 17.82 mg/g for rosemarinic acid to 0.01 mg/g for ferulic acid on dry weight basis. It significantly lowered AGEs, carboxymethyl lysine (CML), and protein glycation in a sugar-protein rich intermediate-moisture-food (IMF) model. Furthermore, the survival rates of MCF-7 cells decreased to 6.02 and 2.16% after 96 h of incubation with 1.0 and 2.0 mg/mL of RE, respectively. The blood glucose, MDA, CHO, TG, and LDLs in diabetic rats of RE treatment were decreased. The RE treatment also enhanced the T-AOC and SOD activity. Furthermore, the RE treatment improved liver function through improving ALP, GPT, and GOT activities in diabetic rats. The results provide important information for the nutriaceutical and pharmaceutical application of rosemary extract.

Rosmarinus plants: Key farm concepts towards food applications

Rosmarinus species are aromatic plants that mainly grow in the Mediterranean region. They are widely used in folk medicine, food, and flavor industries and represent a valuable source of biologically active compounds (e.g., terpenoids, flavonoids, and phenolic acids). The extraction of rosemary essential oil is being done using three main methods: carbon dioxide supercritical extraction, steam distillation, and hydrodistillation. Furthermore, interesting antioxidant, antibacterial, antifungal, antileishmanial, anthelmintic, anticancer, anti-inflammatory, antidepressant, and antiamnesic effects have also been broadly recognized for rosemary plant extracts. Thus the present review summarized data on economically important Rosmarinus officinalis species, including isolation, extraction techniques, chemical composition, pharmaceutical, and food applications.

The role of gut microbiota for the activity of medicinal plants traditionally used in the European Union for gastrointestinal disorders

ETHNOPHARMACOLOGICAL RELEVANCE

Many medicinal plants have been traditionally used for the treatment of gastrointestinal disorders. According to the monographs published by the Committee on Herbal Medicinal Products (HMPC) at the European Medicines Agency, currently 44 medicinal plants are recommended in the European Union for the treatment of gastrointestinal disorders based on traditional use. The main indications are functional and chronic gastrointestinal disorders, such as functional dyspepsia and irritable bowel syndrome (IBS), and typical effects of these plants are stimulation of gastric secretion, spasmolytic and carminative effects, soothing effects on the gastrointestinal mucosa, laxative effects, adstringent or antidiarrheal activities, and anti-inflammatory effects. A possible interaction with human gut microbiota has hardly been considered so far, although it is quite likely.

AIM OF THE STUDY

In this review, we aimed to identify and evaluate published studies which have investigated interactions of these plants with the gut microbiome.

RESULTS

According to this survey, only a minor portion of the 44 medicinal plants considered in EMA monographs for the treatment of gastrointestinal diseases has been studied so far with regard to potential interactions with gut microbiota. We could identify eight relevant in vitro studies that have been performed with six of these medicinal plants, 17 in vivo studies performed in experimental animals involving seven of the medicinal plants, and three trials in humans performed with two of the plants. The most robust evidence exists for the use of inulin as a prebiotic, and in this context also the prebiotic activity of chicory root has been investigated quite intensively. Flaxseed dietary fibers are also known to be fermented by gut microbiota to short chain fatty acids, leading to prebiotic effects. This could cause a health-beneficial modulation of gut microbiota by flaxseed supplementation. In flaxseed, also other compound classes like lignans and polyunsaturated fatty acids are present, that also have been shown to interact with gut microbiota. Drugs rich in tannins and anthocyanins also interact intensively with gut microbiota, since these compounds reach the colon at high levels in unchanged form. Tannins and anthocyanins are intensively metabolized by certain gut bacteria, leading to the generation of small, bioavailable and potentially bioactive metabolites. Moreover, interaction with these compounds may exert a prebiotic-like effect on gut microbiota. Gut microbial metabolization has also been shown for certain licorice constituents, but their potential effects on gut microbiota still need to be investigated in detail. Only a limited amount of studies investigated the interactions of essential oil- and secoiridoid-containing drugs with human gut microbiota. However, other constituents present in some of these drugs, like curcumin (curcuma), shogaol (ginger), and rosmarinic acid have been shown to be metabolized by human gut microbiota, and preliminary data also indicate potential gut microbiome modulatory effects. To conclude, the interaction with gut microbiota is still not fully investigated for many herbal drugs traditionally used for gastrointestinal disorders, which offers a vast field for future research.

Effect of Rosmarinic Acid and Sinapic Acid on Oxidative Stress Parameters in the Cardiac Tissue and Serum of Type 2 Diabetic Female Rats

Cardiovascular diseases are one of the most common complications of type 2 diabetes. They are considered the leading cause of death among diabetics. One of the mechanisms underlying diabetic cardiovascular complications is oxidative stress. Many phenolic acids are regarded as antioxidants. The aim of the study was to investigate the effect of rosmarinic acid (RA) and sinapic acid (SA) on oxidative stress parameters in the cardiac tissue and serum of type 2 diabetic female rats. Additionally, the effect of these compounds on glucose homeostasis and lipid profile in the serum was evaluated. Type 2 diabetes was induced with high-fat diet and streptozotocin. RA at the doses of 10 and 50 mg/kg and SA at the doses of 5 and 25 mg/kg were administrated orally for 28 days. Untreated diabetic rats exhibited unfavorable changes in glucose metabolism and lipid profile. Changes in the enzymatic and non-enzymatic markers indicated the onset of oxidative stress in these animals. The results showed that the higher doses of the tested phenolic acids-50 mg/kg of RA and 25 mg/kg of SA-revealed beneficial effects on oxidative stress in the cardiac tissue of diabetic rats.

Natural Products from Mediterranean Diet: From Anti-hyperlipidemic Agents to Dietary Epigenetic Modulators

Background:

Cardiovascular Diseases (CVD) are, currently, the major contributor to global mortality and will continue to dominate mortality rates in the future. Hyperlipidemia refers to the elevated levels of lipids and cholesterol in the blood, and is also identified as dyslipidemia, manifesting in the form of different disorders of lipoprotein metabolism. These abnormalities may lead to the development of atherosclerosis, which can lead to coronary artery disease and stroke. In recent years, there is a growing interest in the quest for alternative therapeutic treatments based on natural products, offering better recovery and the avoidance of side effects. Recent technological advances have further improved our understanding of the role of epigenetic mechanisms in hyperlipidemic disorders and dietary prevention strategies.

Objective:

This is a comprehensive overview of the anti-hyperlipidemic effects of plant extracts, vegetables, fruits and isolated compounds thereof, with a focus on natural products from the Mediterranean region as well as the possible epigenetic changes in gene expression or cardiometabolic signaling pathways.

Methods:

For the purpose of this study, we searched the PubMed, Scopus and Google Scholar databases for eligible articles and publications over the last five years. The keywords included: “hyperlipidemia”, “plant extract”, “herbs”, “natural products”, “vegetables”, “cholesterol” and others. We initially included all relevant articles referring to in vitro studies, animal studies, Randomized Controlled Trials (RCTs) and previous reviews.

Conclusion:

Many natural products found in the Mediterranean diet have been studied for the treatment of hyperlipidemia. The antihyperlipidemic effect seems to be dose and/or consumption frequency related, which highlights the fact that a healthy diet can only be effective in reversing disease markers if it is consistent and within the framework of a healthy lifestyle. Finally, epigenetic biomarkers are increasingly recognized as new lifestyle management tools to monitor a healthy dietary lifestyle for the prevention of hyperlipidaemic disorders and comorbidities to promote a healthy life.

Therapeutic Potential of Rosmarinic Acid: A Comprehensive Review

Naturally occurring food-derived active ingredients have received huge attention for their chemopreventive and chemotherapy capabilities in several diseases. Rosmarinic acid (RA) is a caffeic acid ester and a naturally-occurring phenolic compound in a number of plants belonging to the Lamiaceae family, such as Rosmarinus officinalis (rosemary) from which it was formerly isolated. RA intervenes in carcinogenesis through different ways, including in tumor cell proliferation, apoptosis, metastasis, and inflammation. On the other hand, it also exerts powerful antimicrobial, anti-inflammatory, antioxidant and even antidepressant, anti-aging effects. The present review aims to provide an overview on anticancer activities of RA and to deliberate its therapeutic potential against a wide variety of diseases. Given the current evidence, RA may be considered as part of the daily diet in the treatment of several diseases, with pre-determined doses avoiding cytotoxicity.

Effect of Rosmarinic Acid on the Serum Parameters of Glucose and Lipid Metabolism and Oxidative Stress in Estrogen-Deficient Rats

Rosmarinic acid is found in medicinal and spice plants such as rosemary, lemon balm, and mint. The aim of the study was to investigate the effect of rosmarinic acid on parameters of glucose and lipid metabolism and parameters of oxidative stress in rats in the early phase of estrogen deficiency. The study was carried out on mature female Wistar rats divided into the following groups: sham-operated control rats, ovariectomized control rats, and ovariectomized rats treated orally with rosmarinic acid at a dose of 10 mg/kg or 50 mg/kg daily for 28 days. The concentration of sex hormones, parameters related to glucose and lipid metabolism as well as parameters of antioxidant abilities and oxidative damage were determined in the blood serum. In the ovariectomized control rats, the homeostasis model assessment of insulin resistance (HOMA-IR) index and cholesterol concentration increased, the superoxide dismutase activity increased, and the reduced glutathione concentration decreased. Administration of rosmarinic acid at both doses induced decreases in the fructosamine concentration and HOMA-IR, an increase in the concentration of reduced glutathione, and a decrease in the concentration of advanced oxidation protein products in ovariectomized rats. Moreover, rosmarinic acid at a dose of 50 mg/kg induced a decrease in the total cholesterol and triglyceride concentrations. The results indicate that rosmarinic acid may be useful in the prevention of metabolic disorders associated with estrogen deficiency, however further studies are necessary.

Interaction between gut microbiota and ethnomedicine constituents

This highlight reviews the interaction processes between gut microbiota and ethnomedicine constituents, which may conceptualize future therapeutic strategies.

Gut microbiota and inflammation in chronic kidney disease and their roles in the development of cardiovascular disease

The health and proper functioning of the cardiovascular and renal systems largely depend on crosstalk in the gut-kidney-heart/vessel triangle. Recent evidence suggests that the gut microbiota has an integral function in this crosstalk. Mounting evidence indicates that the development of chronic kidney and cardiovascular diseases follows chronic inflammatory processes that are affected by the gut microbiota via various immune, metabolic, endocrine, and neurologic pathways. Additionally, deterioration of the function of the cardiovascular and renal systems has been reported to disrupt the original gut microbiota composition, further contributing to the advancement of chronic cardiovascular and renal diseases. Considering the interaction between the gut microbiota and the renal and cardiovascular systems, we can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases.

Prevention of 4-hydroxynonenal-induced lipolytic activation by carnosic acid is related to the induction of glutathione S-transferase in 3T3-L1 adipocytes

Induction of 4-hydroxynonenal (4-HNE), a major lipid peroxidation aldehyde, is observed in patients with obesity and type 2 diabetes mellitus. The lipolytic response by 4-HNE has been linked to insulin resistance. In this study, we investigated the effects of carnosic acid (CA) on 4-HNE-induced lipolysis and the inhibition of β-oxidation in 3T3-L1 adipocytes. The results indicated that cells pretreated with CA reduced 4-HNE-mediated free fatty acid (FFA) release. Furthermore, CA reversed the inhibition of phosphorylation of Tyr⁶³² of insulin receptor substrate-1 (IRS-1) and Akt and the phosphorylation of Ser³⁰⁷ of IRS-1. CA inhibited 4-HNE-induced phosphorylation of protein kinase A (PKA) and hormone-sensitive lipase (HSL), and reversed the suppression by 4-HNE of phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (p < 0.05). Pretreatment of cells with forskolin (a cAMP agonist) and compound C (an AMPK inhibitor) reversed these effects, respectively (p < 0.05). In human subcutaneous adipocytes, CA also attenuated 4-HNE-induced FFA release and the phosphorylation of PKA and HSL (p < 0.05). Moreover, CA increased the protein expression of glutathione S-transferase (GST) A and M. Pretreatment with ethacrynic acid, a GST inhibitor, prevented the 4-HNE-conjugated proteins suppression, the PKA and HSL phosphorylation reduction, and the FFA release inhibition by CA (p < 0.05).

CONCLUSION

The attenuation by CA of the lipolytic response by 4-HNE is likely related to the induction of GST, which in turn reduced 4-HNE-conjugated proteins and decreased the activation of the PKA/HSL pathway. The observed effects may explain how CA improves 4-HNE-induced insulin resistance.