Pinus halepensis essential oil attenuates the toxic Alzheimer’s amyloid beta (1-42)-induced memory impairment and oxidative stress in the rat hippocampus

Bridging the Gap: Harnessing Plant Bioactive Molecules to Target Gut Microbiome Dysfunctions in Amyotrophic Lateral Sclerosis

The correlation between neurodegenerative diseases and the gut microbiome is increasingly evident, with amyotrophic lateral sclerosis (ALS) being particularly notable for its severity and lack of therapeutic options. The gut microbiota, implicated in the pathogenesis and development of ALS, plays a crucial role in the disease. Bioactive plant molecules, specifically volatile compounds in essential oils, offer a promising therapeutic avenue due to their anti-inflammatory properties and gut-modulating effects. Our narrative review aimed to identify microbiota-associated bacteria in ALS and analyze the benefits of administering bioactive plant molecules as much-needed therapeutic options in the management of this disease. A comprehensive search of PubMed database articles published before December 2023, encompassing research on cell, human, and animal ALS models, was conducted. After selecting, analyzing, and discussing key articles, bacteria linked to ALS pathogenesis and physiopathology were identified. Notably, positively highlighted bacteria included Akkermansia muciniphila (Verrucomicrobia phylum), Faecalibacterium prausnitzii, and Butyrivibrio spp. (Firmicutes phylum). Conversely, members of the Escherichia coli spp. (Proteobacteria phylum) and Ruminococcus spp. (Firmicutes phylum) stood out negatively in respect to ALS development. These bacteria were associated with molecular changes linked to ALS pathogenesis and evolution. Bioactive plant molecules can be directly associated with improvements in the microbiome, due to their role in reducing inflammation and oxidative stress, emerging as one of the most promising natural agents for enriching present-day ALS treatments.

A Comprehensive Review of Essential Oils and Their Pharmacological Activities in Neurological Disorders: Exploring Neuroprotective Potential

Numerous studies have demonstrated essential oils' diverse chemical compositions and pharmacological properties encompassing antinociceptive, anxiolytic-like, and anticonvulsant activities, among other notable effects. The utilization of essential oils, whether inhaled, orally ingested, or applied topically, has commonly been employed as adjunctive therapy for individuals experiencing anxiety, insomnia, convulsions, pain, and cognitive impairment. The utilization of synthetic medications in the treatment of various disorders and symptoms is associated with a wide array of negative consequences. Consequently, numerous research groups across the globe have been prompted to explore the efficacy of natural alternatives such as essential oils. This review provides a comprehensive overview of the existing literature on the pharmacological properties of essential oils and their derived compounds and the underlying mechanisms responsible for these observed effects. The primary emphasis is on essential oils and their constituents, specifically targeting the nervous system and exhibiting significant potential in treating neurodegenerative disorders. The current state of research in this field is characterized by its preliminary nature, highlighting the necessity for a more comprehensive overlook of the therapeutic advantages of essential oils and their components. Integrating essential oils into conventional therapies can enhance the effectiveness of comprehensive treatment regimens for neurodegenerative diseases, offering a more holistic approach to addressing the multifaceted nature of these conditions.

Management of the Brain: Essential Oils as Promising Neuroinflammation Modulator in Neurodegenerative Diseases

Neuroinflammation, a pivotal factor in the pathogenesis of various brain disorders, including neurodegenerative diseases, has become a focal point for therapeutic exploration. This review highlights neuroinflammatory mechanisms that hallmark neurodegenerative diseases and the potential benefits of essential oils in counteracting neuroinflammation and oxidative stress, thereby offering a novel strategy for managing and mitigating the impact of various brain disorders. Essential oils, derived from aromatic plants, have emerged as versatile compounds with a myriad of health benefits. Essential oils exhibit robust antioxidant activity, serving as scavengers of free radicals and contributing to cellular defense against oxidative stress. Furthermore, essential oils showcase anti-inflammatory properties, modulating immune responses and mitigating inflammatory processes implicated in various chronic diseases. The intricate mechanisms by which essential oils and phytomolecules exert their anti-inflammatory and antioxidant effects were explored, shedding light on their multifaceted properties. Notably, we discussed their ability to modulate diverse pathways crucial in maintaining oxidative homeostasis and suppressing inflammatory responses, and their capacity to rescue cognitive deficits observed in preclinical models of neurotoxicity and neurodegenerative diseases.

Characterizing cannabis-prevalent terpenes for neuroprotection reveal a role for α and β-pinenes in mitigating amyloid β-evoked neurotoxicity and aggregation in vitro

BACKGROUND

Cannabis sativa L. (C. sativa) can efficiently synthesize of over 200 terpenes, including monoterpenes, sesquiterpenes and triterpenes that may contribute to the known biological activities of phytocannabinoids of relevance for the burgeoning access to medicinal cannabis formulations globally; however, to date have been uncharacterized. We assessed twelve predominant terpenes in C. sativa for neuroprotective and anti-aggregative properties in semi-differentiated PC12 neuronal cell line that is robust and validated as a cell model responsive to amyloid β (Aβ1-42) protein exposure and oxidative stress.

METHODS

Cell viability was assessed biochemically using the MTT assay in the presence of myrcene, β-caryophyllene, terpinolene, limonene, linalool, humulene, α-pinene, nerolidol, β-pinene, terpineol, citronellol and friedelin (1-200 μM) for 24 hr. Sub-toxic threshold test concentrations of each terpene were then applied to cells, alone or with concomitant incubation with the lipid peroxidant tert-butyl hyrdroperoxide (t-BHP; 0-250 μM) or amyloid β (Aβ1-42; 0-1 μM) to assess neuroprotective effects. Direct effects of each terpene on Aβ fibril formation and aggregation were also evaluated using the Thioflavin T (ThT) fluorometric kinetic assay and transmission electron microscopy (TEM) to visualize fibril and aggregate morphology.

RESULTS

Terpenes were intrinsically benign to PC12 cells up to 50 μM, with higher concentrations of β-caryophyllene, humulene and nerolidol inducing some loss of PC12 cell viability. No significant protective effects of terpenes were observed following t-BHP (0-200 µM) administration, with some enhanced toxicity instead demonstrated from both β-caryophyllene and humulene treatment (each at 50 µM). α-pinene and β-pinene demonstrated a significant neuroprotective effect against amyloid β exposure. α-pinene, β-pinene, terpineol, terpinolene and friedelin were associated with a variable inhibition of Aβ1-42 fibril and aggregate density.

CONCLUSIONS

The outcomes of this study underline a neuroprotective role of α-pinene and β-pinene against Aβ-mediated neurotoxicity associated with an inhibition of Aβ1-42 fibrilization and density. This demonstrates the bioactive potential of selected terpenes for consideration in the development of medicinal cannabis formulations targeting neurodegenerative diseases.

Assessment of the Anti-Amyloidogenic Properties of Essential Oils and Their Constituents in Cells Using a Whole-Cell Recombinant Biosensor

Essential oils exhibit numerous medicinal properties, including antimicrobial, anti-inflammatory and antioxidant effects. Recent studies also indicate that certain essential oils demonstrate anti-amyloidogenic activity against β-amyloid, the protein implicated in Alzheimer's disease. To investigate whether the anti-aggregating properties of essential oils extend to α-synuclein, the protein involved in Parkinson's disease, we constructed and employed a whole-cell biosensor based on the split-luciferase complementation assay. We validated our biosensor by using baicalein, a known inhibitor of α-synuclein aggregation, and subsequently we tested eight essential oils commonly used in food and the hygienic industry. Two of them, citron and sage, along with their primary components, pure linalool (the main constituent in citron essential oil) and pure eucalyptol (1,8-cineole, the main constituent in sage essential oil), were able to reduce α-syn aggregation. These findings suggest that both essential oils and their main constituents could be regarded as potential components in functional foods or incorporated into complementary Parkinson's disease therapies.

Neuroprotective effects of a combination of Boswellia papyrifera and Syzygium aromaticum on AlCl3 induced Alzheimer's disease in male albino rat

Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by hippocampal, and cortical neuron deterioration, oxidative stress, and severe cognitive dysfunction. Aluminum is a neurotoxin inducer for cognitive impairments associated with AD. The treatment approaches for AD are unsatisfactory. Boswellia papyrifera and Syzygium aromaticum are known for their pharmacological assets, including antioxidant activity. Therefore, the current study explored the possible mitigating effects of a combination of Boswellia papyrifera and Syzygium aromaticum against aluminum chloride (AlCl3) induced AD. The AD model was established using AlCl3 (100 mg/kg), and the rats were orally administrated with Boswellia papyrifera or Syzygium aromaticum or a combination of them daily for 8 weeks. The Y-maze test was used to test cognition in the rats, while acetylcholinesterase (AChE) and oxidative stress markers were estimated in homogenates of the cerebral cortex and hippocampus. Also, the histopathological examination of the cortex and hippocampus were investigated. The results revealed that administration of either B. papyrifera or S. aromaticum extracts significantly improved the cognitive functions of AD rats, enhanced AChE levels, increased oxidative enzymes levels, including SOD and GSH, and reduced MDA levels in homogenates of the cerebral cortex and hippocampus and confirmed by improvement in histological examination. However, using a combination therapy gave better results compared to a single treatment. In conclusion, the present study provided primary evidence for using a combination of B. papyrifera and S. aromaticum to treat cognitive dysfunction associated with AlCl3 Induced AD by improving the AChE levels and modulating oxidative stress in the brain.

Beta-caryophyllene mitigates the cognitive impairment caused by repeated exposure to aspartame in rats: Putative role of BDNF-TrKB signaling pathway and acetylcholinesterase activity

Aspartame (ASP) is a common sweetener, but studies show it can harm the nervous system, causing learning and memory deficits. β-caryophyllene (BCP), a natural compound found in foods, including bread, coffee, alcoholic beverages, and spices, has already described as a neuroprotector agent. Remarkably, ASP and BCP are commonly consumed, including in the same meal. Therefore, considering that (a) the BCP displays plenty of beneficial effects; (b) the ASP toxicity; and (c) that they can be consumed in the same meal, this study sought to investigate if the BCP would mitigate the memory impairment induced by ASP in rats and investigate the involvement of the brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrKB) signaling pathway and acetylcholinesterase (AChE) activity. Young male Wistar rats received ASP (75 mg/kg; i.g.) and/or BCP (100 mg/kg; i.p.) once daily, for 14 days. At the end of the treatment, the animals were evaluated in the open field and object recognition tests. The cerebral cortex and hippocampus samples were collected for biochemical and molecular analyses. Results showed that the BCP effectively protected against the cognitive damage caused by ASP in short and long-term memories. In addition, BCP mitigated the increase in AChE activity caused by ASP. Molecular insights revealed augmented BDNF and TrKB levels in the hippocampus of rats treated with BCP, indicating greater activation of this pathway. In conclusion, BCP protected against ASP-induced memory impairment. AChE activity and the BDNF/TrkB signaling pathway seem to be potential targets of BCP modulatory role in this study.

Simultaneous Intranasal Codelivery of Donepezil and Memantine in a Nanocolloidal Carrier: Optimization, Pharmacokinetics, and Pharmacodynamics Studies

This work focuses on developing nanoemulsions using a low-energy emulsification method for the codelivery of donepezil and memantine in one dosage form intended to be administered via the intranasal route for enhanced brain delivery. The nanoemulsion formulation was prepared using a low emulsification technique and characterized using various microscopy and nasal ciliotoxicity studies. The safe nanoemulsion was intended for preclinical pharmacokinetics with brain distribution and pharmacodynamics in a scopolamine-induced murine model. The formulated nanoemulsion was 16 nm in size, with a zeta potential of -7.22 mV, and exhibited a spherical shape. The brain concentration of IN-administered NE for DPZ and MEM was ∼678 and 249 ng/mL after 15 min. This concentration is more than 2 times higher in amount when compared with NE administered via PO, free drug solution administered via IN and PO route both. However, the plasma concentration of IN-administered NE for DPZ and MEM was ∼3 and 28 ng/mL after 15 min. In pharmacodynamic studies, the efficacy of NE administered via the IN route was higher when compared with other groups in neurobehavioral, biochemical estimation, and gene expression studies. The results suggest that the IN route can be explored in the future for the delivery of actives via nanocolloidal carriers in the brain for neurological disorders and can serve as promising alternatives for conventional dosage forms and routes.

Inhibitory effects of Jasminum grandiflorum L. essential oil on lipopolysaccharide-induced microglia activation-integrated characteristic analysis of volatile compounds, network pharmacology, and BV-2 cell

Neuroinflammation is considered to have a prominent role in the pathogenesis of Alzheimer's disease (AD). Microglia are the resident macrophages of the central nervous system, and modulating microglia activation is a promising strategy to prevent AD. Essential oil of Jasminum grandiflorum L. flowers is commonly used in folk medicine for the relief of mental pressure and disorders, and analyzing the volatile compound profiles and evaluating the inhibitory effects of J. grandiflorum L. essential oil (JGEO) on the excessive activation of microglia are valuable for its application. This study aims to explore the potential active compounds in JGEO for treating AD by inhibiting microglia activation-integrated network pharmacology, molecular docking, and the microglia model. A headspace solid-phase microextraction combined with the gas chromatography-mass spectrometry procedure was used to analyze the volatile characteristics of the compounds in J. grandiflorum L. flowers at 50°C, 70°C, 90°C, and 100°C for 50 min, respectively. A network pharmacological analysis and molecular docking were used to predict the key compounds, key targets, and binding energies based on the detected compounds in JGEO. In the lipopolysaccharide (LPS)-induced BV-2 cell model, the cells were treated with 100 ng/mL of LPS and JGEO at 7.5, 15.0, and 30 μg/mL, and then, the morphological changes, the production of nitric oxide (NO) and reactive oxygen species, and the expressions of tumor necrosis factor-α, interleukin-1β, and ionized calcium-binding adapter molecule 1 of BV-2 cells were analyzed. A total of 34 compounds with significantly different volatilities were identified. α-Hexylcinnamaldehyde, nerolidol, hexahydrofarnesyl acetone, dodecanal, and decanal were predicted as the top five key compounds, and SRC, EGFR, VEGFA, HSP90AA1, and ESR1 were the top five key targets. In addition, the binding energies between them were less than -3.9 kcal/mol. BV-2 cells were activated by LPS with morphological changes, and JGEO not only could clearly reverse the changes but also significantly inhibited the production of NO and reactive oxygen species and suppressed the expressions of tumor necrosis factor-α, interleukin-1β, and ionized calcium-binding adapter molecule 1. The findings indicate that JGEO could inhibit the overactivation of microglia characterized by decreasing the neuroinflammatory and oxidative stress responses through the multi-compound and multi-target action modes, which support the traditional use of JGEO in treating neuroinflammation-related disorders.

Antidepressant Effects of Essential Oils: A Review of the Past Decade (2012-2022) and Molecular Docking Study of Their Major Chemical Components

Depression is a mental disorder that affects more than 300 million people worldwide. The medications available for treatment take a long time to exhibit therapeutic results and present several side effects. Furthermore, there is a decrease in the quality of life of people suffering from this affliction. Essential oils are traditionally used to relieve the symptoms of depression due to the properties of the constituents of these oils to cross the blood-brain barrier acting on depression-related biological receptors associated with reduced toxicity and side effects. In addition, compared to traditional drugs, they have several administration forms. This review provides a comprehensive assessment of studies on plants whose essential oil has exhibit antidepressant activity in the past decade and the mechanism of action of the major components and models tested. An additional in silico study was conducted with the frequent compounds in the composition of these essential oils, providing a molecular approach to the mechanism of action that has been reported in the past decade. This review is valuable for the development of potential antidepressant medications in addition to providing a molecular approach to the antidepressant mechanism of action of the major volatile compounds that have been reported in the past decade.

Therapeutic potential of aromatic plant extracts in Alzheimer's disease: Comprehensive review of their underlying mechanisms

AIMS

The aim of this review is to outline recent advancements in the application and mechanistic studies of aromatic plant extracts in Alzhermer`s disease (AD) to demonstrate their value in the management of this disease.

BACKGROUND

AD is a neurodegenerative disease with a complex pathogenesis characterized by severe cognitive impairment. Currently, there are very few drugs available for the treatment of AD, and treatments are primarily focused on symptom relief. Aromatherapy is a traditional complementary alternative therapy that focuses on the prevention and treatment of the disease through the inhalation or transdermal administration of aromatic plant extracts. Over the past few years, studies on the use of aromatic plant extracts for the treatment of AD have been increasing and have demonstrated a definitive therapeutic effect.

METHODS

We systematically summarized in vitro, in vivo, and clinical studies focusing on the potential use of aromatic plant extracts in the treatment of AD in PubMed, ScienceDirect, Google Scholar, and the Chinese National Knowledge Infrastructure from 2000 to 2022.

RESULTS

Our literature survey indicates that aromatic plant extracts exert anti-AD effects by modulating pathological changes through anti-amyloid, anti-tau phosphorylation, anti-cholinesterase, anti-inflammation, and anti-oxidative stress mechanisms (Figure 1).

CONCLUSION

This review provides a future strategy for the research of novel anti-AD drugs from aromatic plant extracts.

Natural essential oils derived from herbal medicines: A promising therapy strategy for treating cognitive impairment

Cognitive impairment (CI), mainly Alzheimer’s disease (AD), continues to increase in prevalence and is emerging as one of the major health problems in society. However, until now, there are no first-line therapeutic agents for the allopathic treatment or reversal of the disease course. Therefore, the development of therapeutic modalities or drugs that are effective, easy to use, and suitable for long-term administration is important for the treatment of CI such as AD. Essential oils (EOs) extracted from natural herbs have a wide range of pharmacological components, low toxicity, and wide sources, In this review, we list the history of using volatile oils against cognitive disorders in several countries, summarize EOs and monomeric components with cognitive improvement effects, and find that they mainly act by attenuating the neurotoxicity of amyloid beta, anti-oxidative stress, modulating the central cholinergic system, and improving microglia-mediated neuroinflammation. And combined with aromatherapy, the unique advantages and potential of natural EOs in the treatment of AD and other disorders were discussed. This review hopes to provide scientific basis and new ideas for the development and application of natural medicine EOs in the treatment of CI.

Royal jelly improves learning and memory deficits in an amyloid β-induced model of Alzheimer's disease in male rats: Involvement of oxidative stress

Alzheimer's disease (AD) as the commonest type of dementia is associated with the cognitive function failure. Oxidative stress performs an essential role in the progression of AD. Royal jelly (RJ) is a natural product of bees with antioxidant and anti-inflammatory properties. The present research aimed to investigate the possible protective effect of RJ on learning and memory in a rat model of Aβ-induced AD. Forty male adult Wistar rats were equally distributed into five groups: control, sham-operated, Aβ (receiving intracerebroventricular (ICV) injection of amyloid beta (Aβ1-40)), Aβ + RJ 50 mg/kg, and Aβ + RJ 100 mg/kg. RJ was administered daily post-surgery by oral gavage for four weeks. Behavioral learning and memory were examined using the novel object recognition (NOR) and passive avoidance learning (PAL) tests. Also, oxidative stress markers, such as malondialdehyde (MDA), total oxidant status (TOS) and total antioxidant capacity (TAC), were assessed in the hippocampus. Aβ reduced step-through latency (STLr) and increased time spent in the dark compartment (TDC) in the PAL task and also decreased discrimination index in the NOR test. Administration of RJ ameliorated the Aβ-related memory impairment in both NOR and PAL tasks. Aβ decreased TAC and increased MDA and TOS levels in the hippocampus, whereas RJ administration reversed these Aβ-induced alterations. Our results indicated that RJ has the potential to ameliorate learning and memory impairment in the Aβ model of AD via attenuating oxidative stress.

Natural Bioactive Molecules as Neuromedicines for the Treatment/Prevention of Neurodegenerative Diseases

The brain is vulnerable to different types of stresses, particularly oxidative stress as a result of oxygen requirements/utilization in the body. Large amounts of unsaturated fatty acids present in the brain increase this vulnerability. Neurodegenerative diseases (NDDs) are brain disorders that are characterized by the gradual loss of specific neurons and are attributed to broad evidence of cell-level oxidative stress. The accurate characterization of neurological disorders relies on several parameters along with genetics and environmental risk factors, making therapies less efficient to fight NDDs. On the way to tackle oxidative damage and discover efficient and safe therapies, bioactives are at the edge of NDD science. Naturally occurring bioactive compounds such as polyphenols, carotenoids, essential fatty acids, phytosterols, essential oils, etc. are particularly of interest owing to their potent antioxidant and anti-inflammatory activities, and they offer lots of brain-health-promoting features. This Review focuses on probing the neuroefficacy and bioefficacy of bioactives and their role in supporting relatively low antioxidative and low regenerative capacities of the brain, neurogenesis, neuroprotection, and ameliorating/treating NDDs.

Essential oil composition and biological activities of Aleppo pine (Pinus halepensis Miller) needles collected from different Tunisian regions

The aim of this research was to investigate the variation regarding the chemical composition and biological activities of needles essential oils (EOs) of P. halepensis. Chemical profiles demonstrated a significant (P < 0.05) variability among the different EOs. The main identified compounds were caryophyllene (48.77 ± 2.26), phenyl isovalerate (22.22 ± 2.26), β-myrcene (15.55 ± 5.65) and α-pinene (14.52 ± 2.26). Further, it was shown that EO from Tabouba (Tab) displayed the highest DPPH scavenging (IC₅₀ = 73.03 mg/mL), anti-inflammatory (IC₅₀ = 23.29 µg/mL) and α-glucosidase inhibition activities (IC₅₀ = 254.45 µg/mL). While Elmahres (Elm) exhibited the most potent ABTS radical's inhibition (IC₅₀ = 197.87 mg/mL). For the cytotoxic capacities, Kettana (Ket) was the most efficient against breast cancer MCF-7 cell line with IC₅₀ value better than doxorubicin used as positive control. Obtained results suggest that EO of P. halepensis could be used as a source of bioactive compounds.

Korean Red Pine (Pinus densiflora) Bark Extract Attenuates Aβ-Induced Cognitive Impairment by Regulating Cholinergic Dysfunction and Neuroinflammation

In this study, we investigated the anti-amnesic effect of Korean red pine (Pinus densiflora) bark extract (KRPBE) against amyloid beta_1-42 (Aβ_1-42)-induced neurotoxicity. We found that treatment with KRPBE improved the behavioral function in Aβ-induced mice, and also boosted the antioxidant system in mice by decreasing malondialdehyde (MDA) content, increasing superoxide dismutase (SOD) activities, and reducing glutathione (GSH) levels. In addition, KRPBE improved the cholinergic system by suppressing reduced acetylcholine (ACh) content while also activating acetylcholinesterase (AChE), regulating the expression of choline acetyltransferase (ChAT), postsynaptic density protein-95 (PSD-95), and synaptophysin. KRPBE also showed an ameliorating effect on cerebral mitochondrial deficit by regulating reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and ATP levels. Moreover, KRPBE modulated the expression levels of neurotoxicity indicators Aβ and phosphorylated tau (p-tau) and inflammatory cytokines TNF-α, p-IκB-α, and IL-1β. Furthermore, we found that KRPBE improved the expression levels of neuronal apoptosis-related markers BAX and BCl-2 and increased the expression levels of BDNF and p-CREB. Therefore, this study suggests that KRPBE treatment has an anti-amnestic effect by modulating cholinergic system dysfunction and neuroinflammation in Aβ_1-42-induced cognitive impairment in mice.

Pinus halepensis Essential Oil Ameliorates Aβ1-42-Induced Brain Injury by Diminishing Anxiety, Oxidative Stress, and Neuroinflammation in Rats

The Pinus L. genus comprises around 250 species, being popular worldwide for their medicinal and aromatic properties. The present study aimed to evaluate the P. halepensis Mill. essential oil (PNO) in an Alzheimer’s disease (AD) environment as an anxiolytic and antidepressant agent. The AD-like symptoms were induced in Wistar male rats by intracerebroventricular administration of amyloid beta1-42 (Aβ1-42), and PNO (1% and 3%) was delivered to Aβ1-42 pre-treated rats via inhalation route for 21 consecutive days, 30 min before behavioral assessments. The obtained results indicate PNO’s potential to relieve anxious–depressive features and to restore redox imbalance in the rats exhibiting AD-like neuropsychiatric impairments. Moreover, PNO presented beneficial effects against neuroinflammation and neuroapoptosis in the Aβ1-42 rat AD model.

The effect of minocycline on beta-amyloid-induced memory and learning deficit in male rats: A behavioral, biochemical, and histological study

OBJECTIVES

Minocycline hydrochloride is a semi-synthetic, second-generation tetracycline with neuroprotective, neurorestorative, anti-amyloidogenic, anti-inflammatory, antioxidant, and anti-apoptotic properties. The present study was designed to investigate the potential protective effects of minocycline against beta-amyloid (Aβ)-induced Alzheimer's disease (AD), recognition memory decline, and the possible involved anti-apoptotic mechanisms.

METHODS

The rats were treated with minocycline (50 and 100 mg/kg/day; P.O.) after AD induction for 30 days. Behavioral functions were assessed by employing standard behavioral tests, including novel object recognition (NOR) and passive avoidance learning (PAL) tasks. Then, total antioxidant capacity (TAC) and total oxidant status (TOS) were measured in blood serum using ELISA kits. Apoptosis and the number of Aβ plaques were examined by the TUNEL and Congo red staining, respectively.

RESULTS

Treatment of Aβ rats with minocycline improved memory deficit in the PAL task and a decline in recognition memory in the NOR test. Minocycline at 50 and 100 mg/kg significantly reduced the TOS levels and increased the TAC levels (P < 0.0001). Also, minocycline at 50 and 100 mg/kg reduced the apoptotic index in the hippocampus of Aβ rats. After Congo red staining, the minocycline group showed improved cell morphology and markedly fewer Aβ plaques.

CONCLUSIONS

Minocycline reduced memory and learning deficit in behavioral experiments after Aβ injection, which may be due to its anti-inflammatory and anti-apoptotic effects.

The Importance of Pine Species in the Ethnomedicine of Transylvania (Romania)

The geographical and ecological features of Transylvania enable the wide ethnobotanical use of pine species. The aim of this study was to survey the current ethnomedicinal and other traditional use of pine species of Hungarian-speaking ethnic groups in Transylvania and to compare them with earlier reports performed in Transylvania and from other countries related to the Carpathian Basin. Information on pine species was obtained using semi-structured interviews with 515 Transylvanian informants from 18 villages in the period 2007–2019. The young shoots of Abies alba Mill., Picea abies (L.) H. Karst., Pinus nigra J. F. Arnold, and Pinus sylvestris L. were applied to treat respiratory diseases, while the resin was used for dental problems. Syrup and decoction were made from the cones of all species, except Abies alba. Picea abies was the most frequently documented with seven preparations from different parts (even needles), and this species was mentioned in the treatment of 21 diseases. The least recorded was Abies alba, which was applied for coughs and decayed teeth. We recorded the use of the cones and needles of Picea abies for dyspnoea, thyroid glands, and kidney disorders, previously unknown in ethnomedicinal literature. Our data on the pine species confirm their current use and significance in Transylvania.

Antiproliferative Activities of the Lipophilic Fraction of Eucalyptus camaldulensis against MCF-7 Breast Cancer Cells, UPLC-ESI-QTOF-MS Metabolite Profile, and Antioxidative Functions

Although a number of pharmacological properties have been linked to Eucalyptus camaldulensis leaf essential oil and extracts, the biological attributes of the lipophilic fraction remain unknown. Moreover, only a limited number of active compounds have so far been identified. This work aimed to investigate the anti-oxidative, anti-aggregation, and cytotoxic properties as well as profile the secondary metabolites in the lipophilic fraction of E. camaldulensis leaf extract (Lipo-Eucam) using UHPLC-ESI-QTOF-MS and gas chromatography-mass spectrometry (GC-MS). It was found that Lipo-Eucam possessed potent antioxidant properties against DPPH, ABTS, and FRAP with IC₅₀ values of 31.46, 32.78, and 10.12 μg/mL, respectively. The fraction was able to attenuate metal-catalyzed oxidation of bovine serum albumin (BSA) in a dose-dependent manner (p < 0.05) and abrogated the aggregation of amyloidogenic BSA as revealed by the Congo red assay and transmission electron microscopy. Furthermore, Lipo-Eucam demonstrated potent cytotoxic effects against MCF-7 (IC₅₀ 7.34 μg/mL) but was noncytotoxic at used concentrations against HEK-293 cells (IC₅₀ > 80 μg/mL), suggestive of its selective anticancer properties. Spectrophotometric, UHPLC-MS, and GC-MS analysis revealed that Lipo-Eucam is rich in phenolics, flavonoids, terpenoids, volatile constituents, and a plethora of active metabolites, probably responsible for the observed activities. These findings indicate that Lipo-Eucam is endowed with pharmacologically relevant active principles with strong potential for use in the amelioration of disease conditions related to oxidative stress, protein aggregation, and breast cancer and therefore worthy of further investigations.

Multi-Target Effects of ß-Caryophyllene and Carnosic Acid at the Crossroads of Mitochondrial Dysfunction and Neurodegeneration: From Oxidative Stress to Microglia-Mediated Neuroinflammation

Inflammation and oxidative stress are interlinked and interdependent processes involved in many chronic diseases, including neurodegeneration, diabetes, cardiovascular diseases, and cancer. Therefore, targeting inflammatory pathways may represent a potential therapeutic strategy. Emerging evidence indicates that many phytochemicals extracted from edible plants have the potential to ameliorate the disease phenotypes. In this scenario, ß-caryophyllene (BCP), a bicyclic sesquiterpene, and carnosic acid (CA), an ortho-diphenolic diterpene, were demonstrated to exhibit anti-inflammatory, and antioxidant activities, as well as neuroprotective and mitoprotective effects in different in vitro and in vivo models. BCP essentially promotes its effects by acting as a selective agonist and allosteric modulator of cannabinoid type-2 receptor (CB2R). CA is a pro-electrophilic compound that, in response to oxidation, is converted to its electrophilic form. This can interact and activate the Keap1/Nrf2/ARE transcription pathway, triggering the synthesis of endogenous antioxidant “phase 2” enzymes. However, given the nature of its chemical structure, CA also exhibits direct antioxidant effects. BCP and CA can readily cross the BBB and accumulate in brain regions, giving rise to neuroprotective effects by preventing mitochondrial dysfunction and inhibiting activated microglia, substantially through the activation of pro-survival signalling pathways, including regulation of apoptosis and autophagy, and molecular mechanisms related to mitochondrial quality control. Findings from different in vitro/in vivo experimental models of Parkinson’s disease and Alzheimer’s disease reported the beneficial effects of both compounds, suggesting that their use in treatments may be a promising strategy in the management of neurodegenerative diseases aimed at maintaining mitochondrial homeostasis and ameliorating glia-mediated neuroinflammation.

An Overview of Oxidative Stress, Neuroinflammation, and Neurodegenerative Diseases

Oxidative stress has been linked with a variety of diseases, being involved in the debut and/or progress of several neurodegenerative disorders. This review intends to summarize some of the findings that correlate the overproduction of reactive oxygen species with the pathophysiology of Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. Oxidative stress was also noted to modify the inflammatory response. Even though oxidative stress and neuroinflammation are two totally different pathological events, they are linked and affect one another. Nonetheless, there are still several mechanisms that need to be understood regarding the onset and the progress of neurodegenerative diseases in order to develop efficient therapies. As antioxidants are a means to alter oxidative stress and slow down the symptoms of these neurodegenerative diseases, the most common antioxidants, enzymatic as well as non-enzymatic, have been mentioned in this paper as therapeutic options for the discussed disorders.

Attenuation of Scopolamine-Induced Amnesia via Cholinergic Modulation in Mice by Synthetic Curcumin Analogs

Alzheimer’s disease is an emerging health disorder associated with cognitive decline and memory loss. In this study, six curcumin analogs (1a−1f) were synthesized and screened for in vitro cholinesterase inhibitory potential. On the basis of promising results, they were further investigated for in vivo analysis using elevated plus maze (EPM), Y-maze, and novel object recognition (NOR) behavioral models. The binding mode of the synthesized compounds with the active sites of cholinesterases, and the involvement of the cholinergic system in brain hippocampus was determined. The synthesized curcumin analog 1d (p < 0.001, n = 6), and 1c (p < 0.01, n = 6) showed promising results by decreasing retention time in EPM, significantly increasing % SAP in Y-maze, while significantly (p < 0.001) enhancing the % discrimination index (DI) and the time exploring the novel objects in NORT mice behavioral models. A molecular docking study using MOE software was used for validation of the inhibition of cholinesterase(s). It has been indicated from the current research work that the synthesized curcumin analogs enhanced memory functions in mice models and could be used as valuable therapeutic molecules against neurodegenerative disorders. To determine their exact mechanism of action, further studies are suggested.

Therapeutic effects of crude extracts of Bacopa floribunda on beta-amyloid 1-42-induced Alzheimer’s disease via suppression of dyslipidemia, systemic inflammation and oxidative stress in male Wistar Rats

Aims

Bacopa floribunda (BF), an African traditional plant and its species have been widely used as brain tonic for memory enhancement. It has also been reported to help relieve anxiety and some psychological disorders. This study aimed to investigate the mechanisms of action of BF on Amyloid beta (Aβ) 1–42 peptides induced cognitive deficit in male Wistar rats.

Main methods

A total of 48 healthy male wistar rats were used for this study. Some groups were pre-treated with 200 mg/kg of BF extracts before a single bilateral injection of Aβ 1–42 while some were post-treated with BF for 21 days after Aβ1-42 exposure. Cognitive performance was evaluated using Y-Maze and Novel Object recognition tests. After treatments, hippocampal homogenates were assayed for the levels of Acetylcholinesterase, Na–K/ATPase activities, glutamate and Aβ1-42 concentrations among others.

Key findings

It was observed that Aβ1-42 caused cognitive impairment and BF extracts especially the ethanol extract was able to significantly (p < 0.05) reverse almost all the perturbations including lipid imbalance caused by Aβ1-42 assault mainly at the post-treatment level.

Significance

Administration of ethanol and aqueous extracts of BF mitigated the hazardous effect of Aβ1-42 observed in the blood plasma and hippocampal homogenates. In this context, we conclude that BF is an efficient cognitive enhancer that can help alleviate some symptoms associated with Alzheimer’s disease.

Cannabis terpenes display variable protective and anti-aggregatory actions against neurotoxic β amyloid in vitro: highlighting the protective bioactivity of α-bisabolol in motorneuronal-like NSC-34 cells

BACKGROUND

Terpenes form a diverse class of naturally occurring chemicals ascribed various biological activities. Cannabis contains over 400 different terpenes of varying chemical complexity which may add to the known biological activities of phytocannabinoids of relevance to the increasing use of medical cannabis; however, to date have been incompletely characterized. We assessed three terpenes predominant in cannabis: α-bisabolol, myrcene and β-caryophyllene for neuroprotective and anti-aggregative properties in both undifferentiated and differentiated NSC-34 motorneuronal-like cells as a sensitive model for neurotoxicity to oxidative stress and amyloid β (Aβ_1-42) protein exposure.

METHODS

Cell viability was assessed biochemically using the MTT assay in the presence of either α-bisabolol, myrcene and β-caryophyllene (1-1000µM) for 48hr. Sub-toxic threshold test concentrations of each terpene were then applied to cells, alone or with concomitant incubation with the lipid peroxidant tert-butyl hyrdroperoxide (t-BHP) or amyloid β (Aβ_1-42; 0-1µM) to assess neuroprotective effects. Direct effects of each terpene on Aβ fibril formation and aggregation were also evaluated using the Thioflavin T (ThT) fluorometric kinetic assay, circular dichroism and transmission electron microscopy (TEM) to visualise fibril and aggregate morphology.

RESULTS

Terpenes were intrinsically benign to NSC-34 cells up to 100µM. No significant antioxidant effects were observed following t-BHP administration with myrcene and β-caryophyllene, however α-bisabolol provided a modest but significant increase in cell viability in undifferentiated cells. α-bisabolol also demonstrated a significant neuroprotective effect against amyloid β exposure, with β-caryophyllene also providing a lesser, but significant increase in cell viability. Protective effects of terpenes were more pronounced in undifferentiated versus differentiated cells, attributable more so to an attenuated loss of cell viability in response to Aβ_1-42 following NSC-34 cell differentiation. Neuroprotection was associated with a direct inhibition of Aβ_1-42 fibril and aggregate density, evidenced by both attenuated ThT fluorescence kinetics and both spectral and microscopic evidence of altered and diminished density of Aβ aggregates. While myrcene and β-caryophyllene also elicited reductions in ThT fluorescence and alterations in Aβ aggregation, these were less well associated with neuroprotective capacity.

CONCLUSIONS

These findings highlight a neuroprotective role of α-bisabolol against Aβ-mediated neurotoxicity associated with an inhibition of Aβ fibrillization and modest antioxidant effect against lipid peroxidation, while β-caryophyllene also provided a small but significant measure of protection to Aβ-mediated neurotoxicity. Anti-aggregatory effects were not directly correlated with neuroprotective efficacy. This demonstrates that bioactivity of selected terpenes should be a consideration in the emergent use of medicinal cannabis formulations for the treatment of neurodegenerative diseases.

Nacre extract from pearl oyster attenuates amyloid beta-induced memory impairment

Shells are composed of two types of calcium carbonate polymorphs-the prismatic layer and the nacreous layer. Pearls, composed of the nacreous layer, have been used in Chinese medicine since ancient times. We have previously shown that extracts from the nacreous layer improves scopolamine-induced memory impairment. However, whether pearl ameliorates cognitive disorders induced by amyloid-β 1-40 (Aβ1-40) has not been elucidated. In this study, we investigated whether nacre extract improves memory impairment induced by intracerebroventricular injection of Aβ1-40. Administration of nacre extract led to recovery from Aβ1-40-induced impairments in object recognition, short-term memory, and spatial memory. Nacre extract reversed the increase in lipid peroxidation caused by Aβ1-40 in the cerebral cortex by increasing the expression of catalase and superoxide dismutase. In addition, nacre extract recovered the expression and phosphorylation of cyclic AMP response element-binding protein (CREB), which decreased with Aβ1-40 treatment, and increased the expression of brain-derived neurotrophic factor and neuropeptide Y, which are regulated by CREB. Nacre extract also suppressed acetylcholine esterase activity and Aβ1-40-induced tau phosphorylation. Histochemical analysis of the hippocampus region showed that the nacre extract protected against Aβ1-40-induced neuronal loss in the hippocampus. These results suggest that nacre extract protects against Aβ1-40-induced neuronal cell death by suppressing oxidative stress and increasing the expression and phosphorylation of CREB.

Avicularin Attenuates Memory Impairment in Rats with Amyloid Beta-Induced Alzheimer's Disease

Amyloid-beta-induced Alzheimer's disease (AD) and its further complications are well-established models in preclinical studies and demonstrated by many researchers. Intracerebroventricular injection of Aβ produces brain malfunction, including neurodegeneration and memory impairment. Avicularin is a bioactive flavonoid that has been found to prevent oxidative stress and proinflammatory cytokines. Alzheimer's disease treatment may benefit from inhibiting amyloid-beta and its related complications. Hence, by considering multiple actions of avicularin, including antioxidant and anti-inflammatory, we demonstrated the neuroprotective action of avicularin against amyloid beta-induced neurotoxicity. Aβ_1-42 (1 µg/µl) was dissolved in phosphate buffer solution (pH7.4) and incubated at 37 °C for 3 days to induce aggregation. A single intracerebroventricular (i.c.v.) injection of the Aβ_1-42 was given to the animals utilizing stereotaxic equipment. Avicularin was dissolved in 0.5% sodium carboxymethyl cellulose (CMC), and treatment was given to the animals for 21 days at a dose of (25, 50, and 100 mg/kg, p.o.) after Aβ_1-42 peptide (i.c.v.) injection. Several behavioral studies, acetylcholinesterase activity, oxidative stress, TNFα, IL-6, IL-1β, and expression of BDNF and amyloid-beta were measured. Avicularin treatment (50 and 100 mg/kg) showed cognition enhancement activity in behavioral studies and could reverse the effects of amyloid beta-induced inflammatory response and excessive oxidative stress. Furthermore, the findings reveal that avicularin can halt AD progression by targeting BDNF and amyloid-beta levels in the brain, suggesting that avicularin could be used for Alzheimer's disease treatment.

Designed Peptide Inhibitors of STEP Phosphatase-GluA2 AMPA Receptor Interaction Enhance the Cognitive Performance in Rats

Cognitive impairment and learning ability of the brain are directly linked to synaptic plasticity as measured in changes of long-term potentiation (LTP) and long-term depression (LTD) in animal models of brain diseases. LTD reflects a sustained reduction of the synaptic AMPA receptor content based on targeted clathrin-mediated endocytosis. AMPA receptor endocytosis is initiated by dephosphorylation of Tyr⁸⁷⁶ on the C-terminus of the AMPAR subunit GluA2. The brain-specific striatal-enriched protein tyrosine phosphatase (STEP) is responsible for this process. To identify new, highly effective inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) internalization, we performed structure-based design of peptides able to inhibit STEP-GluA2-CT complex formation. Two short peptide derivatives were found as efficient in vitro inhibitors. Our in vivo experiments evidenced that both peptides restore the memory deficits and display anxiolytic and antidepressant effects in a scopolamine-treated rat model. The interference peptides identified and characterized here represent promising lead compounds for novel cognitive enhancers and/or behavioral modulators.

Inverse molecular docking reveals a novel function of thymol: Inhibition of fat deposition induced by high-dose glucose in Caenorhabditis elegans

As a natural product isolated from thyme oil in thyme, thymol (2-isopropyl-5-methylphenol) harbors antiviral, antioxidant, and other properties, and thus could be potentially used for the treatment of various diseases. However, the function of thymol has not been comprehensively studied. Here, we applied an inverse molecular docking approach to identify unappreciated functions of thymol. Potential targets of thymol in humans were identified by the server of DRAR-CPI, and targets of interest were then assessed by GO and KEGG pathway analysis. Subsequently, homologous proteins of these targets in Caenorhabditis elegans were identified by Blast tool, and their three-dimensional structures were achieved using Swiss-Model workspace. Interaction between thymol and the targeted proteins in worms was verified using AutoDock 4.0. Analyses of the targets revealed that thymol could be potentially involved in the glycolysis/gluconeogenesis and fatty acid degradation pathways. To verify the activity of thymol on lipid deposition in vivo, the C. elegans model was established. The lipid content of nematodes induced by high-dose glucose was determined by Oil Red O and Nile Red staining, and gene expression was assessed by qRT-PCR. The results showed that thymol might lead to the acceleration of β-oxidation by upregulating cpt-1, aco, fabp, and tph-1, causing the descent of lipid content in nematodes. Our findings indicated that thymol could be potentially used for the treatment of chronic metabolic diseases associated with increased fatty acid deposition.

Benefits in Alzheimer's Disease of Sensory and Multisensory Stimulation

Alzheimer's disease (AD) is a serious neurodegenerative disease, which seriously affects the behavior, cognition, and memory of patients. Studies have shown that sensory stimulation can effectively improve the cognition and memory of AD patients, and its role in brain plasticity and neural regulation is initially revealed. This paper aims to review the effect of various sensory stimulation and multisensory stimulation for AD, and to explain the possible mechanism, so as to provide some new ideas for further research in this field. We searched the Web of Science and PubMed databases (from 2000 to October 27, 2020) for literature on the treatment of AD with sensory and multisensory stimulation, including music therapy, aromatherapy, rhythmic (e.g., visual or acoustic) stimulation, light therapy, multisensory stimulation, and virtual reality assisted therapy, then conducted a systematic analysis. Results show these sensory and multisensory stimulations can effectively ameliorate the pathology of AD, arouse memory, and improve cognition and behaviors. What's more, it can cause brain nerve oscillation, enhance brain plasticity, and regulate regional cerebral blood flow. Sensory and multisensory stimulation are very promising therapeutic methods, and they play an important role in the improvement and treatment of AD, but their potential mechanism and stimulation parameters need to be explored and improved.

Investigation on the Antibacterial Activity of Electronic Cigarette Liquids (ECLs): A Proof of Concept Study

BACKGROUND

The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms.

OBJECTIVE

The effect of combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors.

METHODS

Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated.

RESULTS

All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. Higher activity was correlated to the presence of flavors and nicotine.

DISCUSSION

In most cases, the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to the presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth.

CONCLUSION

Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

Chemometric-enhanced metabolic profiling of five Pinus species using HPLC-MS/MS spectrometry: Correlation to in vitro anti-aging, anti-Alzheimer and antidiabetic activities

Detailed metabolic profiling of needles of five Pinus species was investigated using complementary HPLC-MS/MS techniques together with supervised and unsupervised chemometric tools. This resulted in putative identification of 44 compounds belonging to flavonoids, phenolics, lignans, diterpenes and fatty acids. Unsupervised principal component analysis showed that differences were maintained across the metabolites characteristic of each Pinus species, are mainly related to di-O-p-coumaroyltrifolin, p-coumaroyl quinic acid derivative, arachidonic acid, hydroxypalmitic acid, isopimaric acid and its derivative. A supervised Partial Least Squares regression analysis was performed to correlate HPLC-MS/MS profiles with the variation observed in the in vitro anticholinesterase, antiaging and anti-diabetic potential. All investigated Pinus extracts exerted their antiaging activity via increasing telomerase and TERT levels in normal human melanocytes cells compared to the control (untreated cells). Profound inhibition activities of acetylcholinesterase and dipeptidyl peptidase-4 were also observed with P. pinea and P. canariensis extracts having comparable antidiabetic activities to sitagliptin as a standard antidiabetic drug. Our findings suggested that pine needles are a good source of phenolics and diterpenoids that have possible health promoting activities in management and alleviation of diabetic conditions and Alzheimer disease.

Improvement of Oxidative Stress and Mitochondrial Dysfunction by β-Caryophyllene: A Focus on the Nervous System

Mitochondrial dysfunction results in a series of defective cellular events, including decreased adenosine triphosphate (ATP) production, enhanced reactive oxygen species (ROS) output, and altered proteastasis and cellular quality control. An enhanced output of ROS may damage mitochondrial components, such as mitochondrial DNA and elements of the electron transport chain, resulting in the loss of proper electrochemical gradient across the mitochondrial inner membrane and an ensuing shutdown of mitochondrial energy production. Neurons have an increased demand for ATP and oxygen, and thus are more prone to damage induced by mitochondrial dysfunction. Mitochondrial dysfunction, damaged electron transport chains, altered membrane permeability and Ca²⁺ homeostasis, and impaired mitochondrial defense systems induced by oxidative stress, are pathological changes involved in neurodegenerative disorders. A growing body of evidence suggests that the use of antioxidants could stabilize mitochondria and thus may be suitable for preventing neuronal loss. Numerous natural products exhibit the potential to counter oxidative stress and mitochondrial dysfunction; however, science is still looking for a breakthrough in the treatment of neurodegenerative disorders. β-caryophyllene is a bicyclic sesquiterpene, and an active principle of essential oils derived from a large number of spices and food plants. As a selective cannabinoid receptor 2 (CB2) agonist, several studies have reported it as possessing numerous pharmacological activities such as antibacterial (e.g., Helicobacter pylori), antioxidant, anti-inflammatory, analgesic (e.g., neuropathic pain), anti-neurodegenerative and anticancer properties. The present review mainly focuses on the potential of β-caryophyllene in reducing oxidative stress and mitochondrial dysfunction, and its possible links with neuroprotection.

Antioxidant activity of calycosin against α-synuclein amyloid fibrils-induced oxidative stress in neural-like cells as a model of preventive care studies in Parkinson's disease

Protein misfolding and aggregation result in induction of a number of neurodegenerative diseases. In the present study, the anti-fibrillation activity of calycosin and its influence on the amyloid formation of α-synuclein (α-syn) and associated cytotoxicity on neuron-like cells (PC-12) as a model of Parkinson's disease were explored. Therefore, in combination with ThT and ANS fluorescence assay, CD, Congo red absorbance, TEM and cytotoxicity assays (MTT, ROS, SOD activity, CAT activity, GSH content, and caspase-3 activity assays), we showed that calycosin remarkably inhibits α-syn fibril formation through a concentration-dependent manner. The experimental analysis indicated that calycosin exert its antioxidant effects against α-syn amyloid-triggered neurotoxicity by modifying the aggregation pathway toward formation of nontoxic spices via recovering the activity of SOD/CAT and GSH content and reducing the ROS content and caspase-3 activity. This work may provide useful information about the mechanism of α-syn amyloid inhibition by calycosin and pave the way for developing some small molecules-based therapeutic platforms against Parkinson's disease.

Phytochemical and biological activities of Pinus halepensis mill., and their ethnomedicinal use

ETHNOPHARMACOLOGICAL RELEVANCE

Pinus halepensis Mill., is a Mediterranean medicinal plant with numerous traditional applications such as anti-scarring, antiseptic, astringent, antifungal, and anti-tuberculosis. It is used against diarrhea, wounds, rheumatism, cough, gastrointestinal illnesses, hypertension, and hemorrhoids.

AIM OF THE REVIEW

We critically summarized previous reports on the botanical, taxonomical, ecological, geographical distribution, phytochemical, and pharmacological results of P. halepensis Mill.

MATERIALS AND METHODS

To gather data on P. halepensis Mill., different scientific search engines were consulted such as Google Scholar, Scopus, Wiley Online, Scifinder, Web of Science, ScienceDirect, SpringerLink, PubMed. The collected data on P. halepensis Mill., were organised according to ethnomedicinal use, phytochemistry, and pharmacology.

RESULTS

Ethnomedicinal studies indicated that P. halepensis Mill., is used as a protective remedy against respiratory and digestive disorders, arterial hypertension, microbial infections. These medicinal uses vary based on the part used and regions. The extracts and essential oils of P. halepensis Mill., demonstrated several biological effects including antimicrobial, antidiabetic anti-inflammatory, cytotoxic, antiparasitic, and hepatoprotective. Traditional uses and biological effects of P. halepensis Mill., were attributed to the numerous molecules that belong to different chemical classes such as terpenoids, phenolic acids, flavonoids, fatty acids and steroids, aldehydes and ketones.

CONCLUSIONS

In vitro and in vivo investigations of P. halepensis Mill., extracts and essential oils showed interesting pharmacological activities supporting the traditional use of this species. Previous reports indicated that P. halepensis Mill., extracts and their constituents exhibited potent antibacterial, antifungal, antioxidant, protective, anticoagulant, anti-hemolytic, and anti-inflammatory effects. Further investigation is needed to reveal the full biological spectra of P. halepensis Mill., extracts and essential oils (using in vivo models) and to validate their industrial applications as a food additive. However, in-depth studies are required to investigate the biological properties and molecular mechanisms of P. halepensis Mill., secondary metabolites in the management of diabetes mellitus and the prevention of the neurodegenerative disorders development such as Alzheimer's and Parkinson's disease. Studies exploring pharmacological effects of P. halepensis Mill., bioactive components such as the antimicrobial, anti-inflammatory, and antiparasitic drugs are required to validate the clinical use of these molecules. The safety of P. halepensis Mill., and its bioactive compounds should be also investigated by carrying out further pharmacokinetic and toxicological experiments.

Conifer Essential Oils Reversed Amyloid Beta1-42 Action by Modulating BDNF and ARC Expression in The Rat Hippocampus

BACKGROUND

The conifer species Pinus halepensis (Pinaceae) and Tetraclinis articulata (Cupressaceae) are widely used in traditional medicine due to their health beneficial properties.

OBJECTIVE

This study aimed to investigate the mechanisms by which P. halepensis and T. articulata essential oils (1% and 3%) could exhibit neuroprotective effects in an Alzheimer's disease (AD) rat model, induced by intracerebroventricular (i.c.v.) administration of amyloid beta1-42 (Aβ1-42).

METHOD

The essential oils were administered by inhalation to the AD rat model, once daily, for 21 days. DNA fragmentation was assessed through Cell Death Detection ELISA kit. Brain-derived neurotrophic factor (BDNF), activity-regulated cytoskeleton-associated protein (ARC) and interleukin-1β (IL-1β) gene expressions were determined by RT-qPCR analysis, while BDNF and ARC protein expressions were assessed using immunohistochemistry technique.

RESULTS

Our data showed that both essential oils substantially attenuated memory impairments, with P. halepensis mainly stimulating ARC expression and T. articulata mostly enhancing BDNF expression. Also, the inhalation of essential oils reduced IL-1β expression and induced positive effects against DNA fragmentation associated with Aβ1-42-induced toxicity, further contributing to the cognitive improvement in the rats with AD-like model.

CONCLUSION

Our findings provide further evidence that these essential oils and their chemical constituents could be natural agents of therapeutic interest against Aβ1-42-induced neurotoxicity.

Essential Oils as a Potential Neuroprotective Remedy for Age-Related Neurodegenerative Diseases: A Review

Despite the improvements in life expectancy, neurodegenerative conditions have arguably become the most dreaded maladies of older people. The neuroprotective and anti-ageing potentials of essential oils (EOs) are widely evaluated around the globe. The objective of this review is to analyse the effectiveness of EOs as neuroprotective remedies among the four common age-related neurodegenerative diseases. The literature was extracted from three databases (PubMed, Web of Science and Google Scholar) between the years of 2010 to 2020 using the medical subject heading (MeSH) terms "essential oil", crossed with "Alzheimer's disease (AD)", "Huntington's disease (HD)", "Parkinson's disease (PD)" or "amyotrophic lateral sclerosis (ALS)". Eighty three percent (83%) of the studies were focused on AD, while another 12% focused on PD. No classifiable study was recorded on HD or ALS. EO from Salvia officinalis has been recorded as one of the most effective acetylcholinesterase and butyrylcholinesterase inhibitors. However, only Cinnamomum sp. has been assessed for its effectiveness in both AD and PD. Our review provided useful evidence on EOs as potential neuroprotective remedies for age-related neurodegenerative diseases.

The essential oil of the leaves of Verbesina macrophylla (Cass.) S.F.Blake has antimicrobial, anti-inflammatory and antipyretic activities and is toxicologically safe

ETHNOPHARMACOLOGICAL RELEVANCE

Verbesina macrophylla (Cass.) S.F.Blake is a medicinal plant from South America, popularly known as "asa de peixe", "asa de peixe branco", "cambará branco" or "cambará guaçu", being used by traditional communities for its healing powers in the form of teas, infusions, liqueurs and extracts, for the treatment of bacterial and fungal infections of the urinary and respiratory tracts, such as kidney problems, bronchitis, inflammation and fever. However, none of the ethnopharmacological properties has been scientifically evaluated.

AIM OF THE STUDY

Based on the ethnopharmacological use of the species, this study investigated the chemical composition, and for the first time acute toxicity, hemolytic, antimicrobial, anti-inflammatory and antipyretic activities of the essential oil from leaves of V. macrophylla.

MATERIAL AND METHODS

The essential oil was obtained from the leaves by hydrodistillation (HD), being characterized by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography coupled to flame ionization detection (GC-FID). The antimicrobial activity was evaluated by the broth microdilution technique in bacteria and fungi that cause infections of the respiratory and urinary tract, and toxicological safety regarding hemolytic activity on human red blood cells (hRBCs), and acute toxicity in mice. The anti-inflammatory activity was evaluated by the model carrageenan-induced peritonitis with quantification of the levels of TNF-α and IL-1β in the intraperitoneal fluid, and ear edema induced by croton oil. The antipyretic activity evaluated in mice with pyrexia induced by yeast.

RESULTS

The extraction of essential oil by hydrodistillation (HD) showed a yield of 0.33 ± 0.04%, with its composition constituted mainly by sesquiterpenes of hydrocarbons (94.00%). The essential oil demonstrated antibacterial and antifungal activity, with a low rate of hemolysis in human red blood cells (hRBCs) and no clinical signs of toxicity were observed in animals after acute treatment, which suggested that the LD₅₀ is greater than 5000 mg/kg; p.o. The essential oil demonstrated anti-inflammatory activity reducing levels of pro-inflammatory cytokines TNF-α (38.83%, 72.42% and 73.52%) and IL-1β (37.70%, 75.92% and 87.71%), and ear edema by 49.53%, 85.04% and 94.39% at concentrations of 4, 40 and 400 mg/kg, respectively. The antipyretic activity presented by the essential oil is statistically similar to dipyrone.

CONCLUSION

The set of results obtained, validates the main activities attributed to the traditional use of Verbesina macrophylla (Cass.) S.F.Blake. These data add industrial value to the species, considering that the antimicrobial, anti-inflammatory and antipyretic activities present results similar to the drugs already used also presenting safety. The results suggest that essential oil from V. macrophylla may be used by industry for the development of drugs with natural antimicrobial, anti-inflammatory and antipyretic effect.

Chemical constituents and anticholinesterase activity of the essential oil of Algerian Elaeoselinum thapsioides (Desf.) maire

Elaeoselinum thapsioides (Desf.) Maire (Apiaceae) is an Algerian medicinal plant used in traditional medicine to treat different diseases. The essential oil obtained by hydrodistillation from the aerial parts of Elaeoselinum thapsioides growing wild in Algeria, was analyzed by GC-MS for the first time. Forty-five compounds were detected, accounting for 93.8% of the total oil, which was characterized by a high content of hydrocarbons derivatives of monoterpenes (75.9%). Myrcene (61.0%) was the principal constituent of the essential oil, followed by germacrene D (10.3%), α-pinene (6.5%) and β-pinene (2.9%). In vitro anticholinesterase activity of the essential oil was investigated by the Ellman method that evidenced a low acetylcholinesterase and butyrylcholinesterase inhibitory effect.

Antioxidant Potential of Pine Needles: A Systematic Study on the Essential Oils and Extracts of 46 Species of the Genus Pinus

The antioxidant activity of the essential oils, as well as of the organic and hydroethanolic extracts, of the fresh needles of 54 pine taxa was evaluated using the peroxy-oxalate and luminol chemiluminescence assays. Among all evaluated essential oils, P. canariensis and P. attenuata displayed the highest levels of activity. P. contorta var. murrayana, followed by P. nigra var. caramanica, exhibited the highest antioxidant capacity among the organic extracts, while the most active hydroethanolic extract was that of P. nigra subsp. nigra. Based on the overall levels of activity, the latter taxon was selected for phytochemical analysis targeting the isolation of the bioactive constituents. As such, the organic extract of P. nigra subsp. nigra was subjected to chromatographic separations to yield 11 secondary metabolites (1-11) that were evaluated for their antioxidant activity. Nonetheless, the isolated compounds were found to be less active than the crude extract, thus suggesting the potential role of synergism.

Optimization of Surfactant- and Cosurfactant-Aided Pine Oil Nanoemulsions by Isothermal Low-Energy Methods for Anticholinesterase Activity

Highly stable pine oil-loaded nanoemulsions were evaluated for nutraceutical and storage stability applications. Pine oil-loaded nanoemulsion preparation was done with pine oil as the oily phase and additionally with different ratios of the non-ionic surfactant (Tween 80) and cosurfactant (ethanol) in an aqueous solution using the isothermal low-energy or spontaneous emulsification method. A transparent and stable nanoemulsion was obtained with a combination of pine oil (5 wt %), surfactant mixture (35 wt %), and water quantity sufficient (qs) by the isothermal low-energy method. The mean droplet size and ζ-potential of the fabricated nanoemulsion were ≈14 nm and -3.4 mV, respectively. The size of the transparent nanoemulsion increased to ∼45 nm and showed turbidity at 60 °C. Microrheological investigation highlighted the gel-sol-gel conversion in the presence of applied angular frequency at 25 °C. The loss modulus shifted to lower frequency at 60 °C in comparison to other temperatures. The anticholinesterase (AChE) inhibition activity of the pine oil-loaded nanoemulsion suggested a possible therapeutic value, and at 0.10% concentration of the nanoemulsion, the AChE inhibition activity was ≈95.72 ± 5.59%. These studies have important implications in fabrication and optimization of a nanoemulsion as a delivery system for combating reminiscence in Alzheimer's disease and application in the nutraceutical-based industry. This isothermal low-energy method offers an advantage of preparing an edible oil delivery system using simple and rapid operational parameters.

Humanin: A mitochondrial-derived peptide in the treatment of apoptosis-related diseases

Humanin (HN) is a small mitochondrial-derived cytoprotective polypeptide encoded by mtDNA. HN exhibits protective effects in several cell types, including leukocytes, germ cells, neurons, tissues against cellular stress conditions and apoptosis through regulating various signaling mechanisms, such as JAK/STAT pathway and interaction of BCL-2 family of protein. HN is an essential cytoprotective peptide in the human body that regulates mitochondrial functions under stress conditions. The present review aims to evaluate HN peptide's antiapoptotic activities as a potential therapeutic target in the treatment of cancer, diabetes mellitus, male infertility, bone-related diseases, cardiac diseases, and brain diseases. Based on in vitro and in vivo studies, HN significantly suppressed the apoptosis during the treatment of bone osteoporosis, cardiovascular diseases, diabetes mellitus, and neurodegenerative diseases. According to accumulated data, it is concluded that HN exerts the proapoptotic activity of TNF-α in cancer, which makes HN as a novel therapeutic agent in the treatment of cancer and suggested that along with HN, the development of another mitochondrial-derived peptide could be a viable therapeutic option against different oxidative stress and apoptosis-related diseases.

Inhibitor Kappa B Kinase β, Modulated by DJ-1/p-VHL, Reduces Phosphorylated Tau (p-Tau) Accumulation via Autophagy in Alzheimer's Disease Model

It has been demonstrated Inhibitor Kappa B Kinase β (IKKβ) facilitates autophagy, which in turn mediates p-Tau protein clearance. However, the specific regulatory mechanism in Alzheimer's disease (AD) remains unclear. Firstly, AD model was generated by the intracerebroventricular (ICV) injection of the Β-amyloid 1-42 (Aβ_1-42) peptide. Subsequently, mice were injected with shRNA adenoviral transduction particles designed to target DJ-1 or Aβ_1-42 or Aβ_1-42 + shNC or Aβ_1-42 + shRNA against DJ-1. shRNA against DJ-1 were injected into hippocampus of mice (8 × 10⁴ viral particles for each mice) for seven consecutive days. Immunohistochemistry was performed to detect the accumulation of Aβ in the hippocampus of mice, and Hematoxylin-Eosin (HE) staining assay was carried to detect pathological changes in the hippocampus of mice. Further, sh-IKKβ, shDJ-1, pcDNA-IKKβ and pcDNA-DJ-1 plasmids were transfected into HT-22 cells, MTT assay, TUNEL staining and Hoechst staining were performed to detect cell viability and apoptosis, respectively. Western blotting was carried to measure the relative expression of proteins. Findings indicated that Aβ_1-42 inhibited autophagy and up-regulated p-Tau protein expression; Overexpression of IKKβ and DJ-1 all rescued the autophagy inhibited by Aβ_1-42 and down-regulated p-Tau protein expression induced by Aβ_1-42; DJ-1 up-regulated IKKβ via p-VHL, further promoted autophagy and reduced the expression of p-Tau protein; DJ-1 knockdown inhibited autophagy and up-regulated p-Tau protein expression, resulting in delayed behavior in mice. In conclusion, IKKβ, modulated by DJ-1/p-VHL, reduces p-Tau accumulation via autophagy in AD's disease model. This study may provide theoretical basis for the treatment of AD.

Memory-Enhancing Effects of Origanum majorana Essential Oil in an Alzheimer's Amyloid beta1-42 Rat Model: A Molecular and Behavioral Study

Origanum L. (Lamiaceae) is an important genus of medicinal and aromatic plants used in traditional medicine since ancient times as culinary herbs and remedies. The aim of the present study was to evaluate the chemical composition, as well as the biochemical and cellular activities of freshly prepared Origanum majorana L. essential oil (OmEO) in an Alzheimer’s disease (AD) amyloid beta1-42 (Aβ1-42) rat model. OmEO (1% and 3%) was inhaled for 21 consecutive days, while Aβ1-42 was administered intracerebroventricularly to induce AD-like symptoms. Our data demonstrate that OmEO increased antioxidant activity and enhanced brain-derived neurotrophic factor (BDNF) expression, which in concert contributed to the improvement of cognitive function of animals. Moreover, OmEO presented beneficial effects on memory performance in Y-maze and radial arm-maze tests in the Aβ1-42 rat AD model.

Quantitative Analysis of 7 Compounds in Diospyros lotus Leaf Extract and Its Biological Effects on Neuroprotection and Antineuroinflammation

Diospyros lotus L. (Ebenaceae) is a deciduous plant that was traditionally used to treat various diseases such as sedation, constipation, and hypertension. However, its effects on Alzheimer’s diseases (AD) have not been reported. We investigated the potent biological effects of D. lotus on AD and performed quantitative analysis of 7 standard compounds in D. lotus leaves. First, two parts leaf and branch of D. lotus were compared to examine the effects on amyloid-β (Aβ) aggregation and oxidative stress. Ethanol extract of D. lotus leaves (EDLL) had higher activities on the Aβ disaggregation and antioxidation compared with ethanol extract of D. lotus branches (EDLB). Second, we have focused on the biological activities of EDLL for neurocellular analyses. In HT22 neuronal cells, EDLL reversed hydrogen peroxide (H2O2)-damaged cell death. In BV-2 microglia, EDLL suppressed lipopolysaccharide-stimulated productions of nitric oxide (NO) and prostaglandin E2. Third, we performed quantitative analyses of 7 standard compounds in D. lotus using high-performance liquid chromatography. Among 7 compounds, myricitrin (44.189 mg/g) was the most abundant compound in EDLL. Myricetin presented the marked inhibitory effect on Aβ aggregation, indicating its potential as a bioactive compound to control Aβ aggregation. Overall, this study suggests that EDLL may be a promising therapeutic agent for AD via Aβ disaggregation, and inhibition of neuronal cell damage and inflammation.

(-)-cis-Carveol, a Natural Compound, Improves β-Amyloid-Peptide 1-42-Induced Memory Impairment and Oxidative Stress in the Rat Hippocampus

Alzheimer's disease (AD) could be considered a multifactorial neurodegenerative disorder characterized by the accumulation of the β-amyloid-peptide (Aβ) within the brain leading to cognitive deficits, oxidative stress, and neuroinflammation. The present work was carried out to investigate the neuroprotective effect of (-)-cis-carveol (1% and 3%, for 21 days) against the β-amyloid-peptide 1-42- (Aβ1-42-) induced AD. Twenty-five rats were divided into five groups (n = 5/group): the first group-control (sham-operated); the second group-Aβ1-42 (1 mM) that received donepezil treatment (5 mg/kg, as the positive reference drug in the Y-maze and the radial arm maze tests); the third group-Aβ1-42 (1 mM); the fourth and fifth groups-Aβ1-42 (1 mM) that received (-)-cis-carveol treatment groups (1% and 3%). The results of this study demonstrated that (-)-cis-carveol improved Aβ1-42-induced memory deficits examined by using Y-maze and radial arm maze in vivo tests. Also, the biochemical analyses of the hippocampus homogenates showed that (-)-cis-carveol reduced hippocampal oxidative stress caused by Aβ1-42. Our results suggested that the use of (-)-cis-carveol may be suitable for decreasing AD-related symptoms.

Cognitive Facilitation and Antioxidant Effects of an Essential Oil Mix on Scopolamine-Induced Amnesia in Rats: Molecular Modeling of In Vitro and In Vivo Approaches

The present study investigated the capability of an essential oil mix (MO: 1% and 3%) in ameliorating amnesia and brain oxidative stress in a rat model of scopolamine (Sco) and tried to explore the underlying mechanism. The MO was administered by inhalation to rats once daily for 21 days, while Sco (0.7 mg/kg) treatment was delivered 30 min before behavioral tests. Donepezil (DP: 5 mg/kg) was used as a positive reference drug. The cognitive-enhancing effects of the MO in the Sco rat model were assessed in the Y-maze, radial arm maze (RAM), and novel object recognition (NOR) tests. As identified by gas chromatography–mass spectrometry (GC–MS), the chemical composition of the MO is comprised by limonene (91.11%), followed by γ-terpinene (2.02%), β-myrcene (1.92%), β-pinene (1.76%), α-pinene (1.01%), sabinene (0.67%), linalool (0.55%), cymene (0.53%), and valencene (0.43%). Molecular interactions of limonene as the major compound in MO with the active site of butyrylcholinesterase (BChE) was explored via molecular docking experiments, and Van der Waals (vdW) contacts were observed between limonene and the active site residues SER198, HIS438, LEU286, VAL288, and PHE329. The brain oxidative status and acetylcholinesterase (AChE) and BChE inhibitory activities were also determined. MO reversed Sco-induced memory deficits and brain oxidative stress, along with cholinesterase inhibitory effects, which is an important mechanism in the anti-amnesia effect. Our present findings suggest that MO ameliorated memory impairment induced by Sco via restoration of the cholinergic system activity and brain antioxidant status.

Geographic Differences in Element Accumulation in Needles of Aleppo Pines (Pinus halepensis Mill.) Grown in Mediterranean Region

Pine needles are widely used as bio-indicators due to their worldwide distribution and the ease of sample collection. In contrast to deciduous trees, conifers offer the possibility of monitoring long-term exposure through older needles. Pinus halepensis Miller is a pine species native to the Mediterranean region, which has been used for restoration activities in arid and semiarid areas leading to vast spatial expansion. Needles from pine trees collected in the southeastern to northwestern extension of Croatia’s coastal area at twelve sampling sites were analysed for twenty-one metals and metalloids. Statistical evaluation of the obtained data revealed significant differences for Al, As, B, Ba, Ca, Cr, Fe, K, Mg, Mn, Na, Se, and Sr between the different regions. Needles from trees growing on islands did not show elevated levels of Mg and/or Na as a result of the sea spray influence. The differences in metal accumulation are supposed to be linked to the environmental conditions at the respective sampling site, since the species was the same everywhere. By comparing the elemental contents of the soil those of with needles, it can be clearly seen, that the root as well as the foliar uptake contribute to the final amount.