Potential Therapeutic Use of the Rosemary Diterpene Carnosic Acid for Alzheimer’s Disease, Parkinson’s Disease, and Long-COVID through NRF2 Activation to Counteract the NLRP3 Inflammasome

Rosemary (Rosmarinus officinalis [family Lamiaceae]), an herb of economic and gustatory repute, is employed in traditional medicines in many countries. Rosemary contains carnosic acid (CA) and carnosol (CS), abietane-type phenolic diterpenes, which account for most of its biological and pharmacological actions, although claims have also been made for contributions of another constituent, rosmarinic acid. This review focuses on the potential applications of CA and CS for Alzheimer’s disease (AD), Parkinson’s disease (PD), and coronavirus disease 2019 (COVID-19), in part via inhibition of the NLRP3 inflammasome. CA exerts antioxidant, anti-inflammatory, and neuroprotective effects via phase 2 enzyme induction initiated by activation of the KEAP1/NRF2 transcriptional pathway, which in turn attenuates NLRP3 activation. In addition, we propose that CA-related compounds may serve as therapeutics against the brain-related after-effects of SARS-CoV-2 infection, termed “long-COVID.” One factor that contributes to COVID-19 is cytokine storm emanating from macrophages as a result of unregulated inflammation in and around lung epithelial and endovascular cells. Additionally, neurological aftereffects such as anxiety and “brain fog” are becoming a major issue for both the pandemic and post-pandemic period. Many reports hold that unregulated NLRP3 inflammasome activation may potentially contribute to the severity of COVID-19 and its aftermath. It is therefore possible that suppression of NLRP3 inflammasome activity may prove efficacious against both acute lung disease and chronic neurological after-effects. Because CA has been shown to not only act systemically but also to penetrate the blood–brain barrier and reach the brain parenchyma to exert neuroprotective effects, we discuss the evidence that CA or rosemary extracts containing CA may represent an effective countermeasure against both acute and chronic pathological events initiated by SARS-CoV-2 infection as well as other chronic neurodegenerative diseases including AD and PD.

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.

Antioxidative Effect of Sage (Salvia officinalis L.) Macerate as “Green Extract” in Inhibiting the Oxidation of Fish Oil

The aim of the study was to assess the antioxidant effect of concentrated oil macerate of sage (M) as a “green extract” in inhibiting the oxidation of Fish Oil (FO). In the homogenization-assisted maceration process, FO was used as a solvent for the sage active substances to produce M, which was then added to FO (25% w/w) and evaluated for its effect by monitoring the level of oxidation during refrigerated and room temperature storage. The macerate also examined polyphenols, plant pigments, DPPH antioxidant potential, oxidation level and sensory quality. It was shown that the maceration process made it possible to obtain aromatized M, containing polyphenols (carnosic acid, carnosol) and pigments, but with an increased level of peroxides, free fatty acids, compared to the control oil. M showed antioxidant properties and inhibited FO oxidation. It showed the best efficiency in FO during refrigerated storage, in the third month it reduced the level of peroxides by about 9 times, compared to the control. M retains unchanged quality at refrigerated temperature for up to 3 months. Sage macerates are „green extracts” that can be used as effective natural antioxidant additives, following preparation improvements to reduce the amount of peroxide formed.

Potential Inhibitors Identification of Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2) Angiotensin-Converting Enzyme 2 and Main Protease from Anatolian Traditional Plants

Background: The 2019 novel coronavirus disease (COVID-19) has caused a global health catastrophe by affecting the whole human population around the globe. Unfortunately, there is no specific medication or treatment for COVID-19 currently available. Objective: It’s extremely necessary to apply effective drug treatment in order to end the pandemic period and return daily life to normal. In terms of the urgency of treatment, rather than focusing on the discovery of novel compounds, it is critical to explore the effects of existing herbal agents with proven antiviral properties on the virus. Method: Molecular docking studies were carried out with three different methods, Glide extra precision (XP) docking, Induced Fit docking (IFD), and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA), to determine the potential effects of 58 phytochemicals in the content of Rosmarinus officinalis, Thymbra spicata, Satureja thymbra, and Stachys lavandulifolia plants -have antiviral and antibacterial effects- against Main Protease (Mpro) and Angiotensin Converting Enzyme 2 (ACE2) enzymes. Results: 7 compounds stand out among all molecules by showing very high binding affinities. According to our findings, the substances chlorogenic acid, rosmarinic acid, and rosmanol exhibit extremely significant binding affinities for both Mpro and ACE2 enzymes. Furthermore, it was discovered that carnosic acid and alpha-cadinol showed potential anti-Mpro activity, whereas caffeic acid and carvacrol had promising anti-ACE2 activity. Conclusion: Chlorogenic acid, rosmarinic acid, rosmanol, carnosic acid, alpha-cadinol, caffeic acid, and carvacrol compounds have been shown to be powerful anti-SARS-COV-2 agents in docking simulations against Mpro and ACE2 enzymes, as well as ADME investigations.

Mechanistic Insights into Biological Activities of Polyphenolic Compounds from Rosemary Obtained by Inverse Molecular Docking

Rosemary (Rosmarinus officinalis L.) represents a medicinal plant known for its various health-promoting properties. Its extracts and essential oils exhibit antioxidative, anti-inflammatory, anticarcinogenic, and antimicrobial activities. The main compounds responsible for these effects are the diterpenes carnosic acid, carnosol, and rosmanol, as well as the phenolic acid ester rosmarinic acid. However, surprisingly little is known about the molecular mechanisms responsible for the pharmacological activities of rosemary and its compounds. To discern these mechanisms, we performed a large-scale inverse molecular docking study to identify their potential protein targets. Listed compounds were separately docked into predicted binding sites of all non-redundant holo proteins from the Protein Data Bank and those with the top scores were further examined. We focused on proteins directly related to human health, including human and mammalian proteins as well as proteins from pathogenic bacteria, viruses, and parasites. The observed interactions of rosemary compounds indeed confirm the beforementioned activities, whereas we also identified their potential for anticoagulant and antiparasitic actions. The obtained results were carefully checked against the existing experimental findings from the scientific literature as well as further validated using both redocking procedures and retrospective metrics.

Nutraceuticals Synergistically Promote Osteogenesis in Cultured 7F2 Osteoblasts and Mitigate Inhibition of Differentiation and Maturation in Simulated Microgravity

Microgravity is known to impact bone health, similar to mechanical unloading on Earth. In the absence of countermeasures, bone formation and mineral deposition are strongly inhibited in Space. There is an unmet need to identify nutritional countermeasures. Curcumin and carnosic acid are phytonutrients with anticancer, anti-inflammatory, and antioxidative effects and may exhibit osteogenic properties. Zinc is a trace element essential for bone formation. We hypothesized that these nutraceuticals could counteract the microgravity-induced inhibition of osteogenic differentiation and function. To test this hypothesis, we cultured 7F2 murine osteoblasts in simulated microgravity (SMG) in a Random Positioning Machine in the presence and absence of curcumin, carnosic acid, and zinc and evaluated cell proliferation, function, and differentiation. SMG enhanced cell proliferation in osteogenic medium. The nutraceuticals partially reversed the inhibitory effects of SMG on alkaline phosphatase (ALP) activity and did not alter the SMG-induced reduction in the expression of osteogenic marker genes in osteogenic medium, while they promoted osteoblast proliferation and ALP activity in the absence of traditional osteogenic media. We further observed a synergistic effect of the intermix of the phytonutrients on ALP activity. Intermixes of phytonutrients may serve as convenient and effective nutritional countermeasures against bone loss in space.

Protective Effects of Carnosic Acid on Lipopolysaccharide-Induced Acute Kidney Injury in Mice

Septic acute kidney injury (AKI) is an important medical problem worldwide, but current treatments are limited. During sepsis, lipopolysaccharide (LPS) activates various signaling pathways involved in multiorgan failure. Carnosic acid is a natural phenolic diterpene and has multiple bioactivities, such as anti-tumor, anti-inflammatory, and anti-oxidative effects. However, the effect of carnosic acid on septic AKI has not been explored. Therefore, this study aimed to determine whether carnosic acid has a therapeutic effect on LPS-induced kidney injury. Administration of carnosic acid after LPS injection ameliorated histological abnormalities and renal dysfunction. Cytokine production, immune cell infiltration, and nuclear factor-κB activation after LPS injection were also alleviated by carnosic acid. The compound suppressed oxidative stress with the modulation of pro-oxidant and antioxidant enzymes. Tubular cell apoptosis and caspase-3 activation were also inhibited by carnosic acid. These data suggest that carnosic acid ameliorates LPS-induced AKI via inhibition of inflammation, oxidative stress, and apoptosis and could serve as a useful treatment agent for septic AKI.

Absorption and Transport Characteristics and Mechanisms of Carnosic Acid

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 (Papp) 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.