Intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevents the H-89-induced spatial learning deficits in Morris water maze.

OBJECTIVES: H-89 (a protein kinase AII [PKA II] inhibitor) impairs the spatial memory in the Morris water maze task in rats. In the present study, we aimed to study the protective effects of nicotine and O-acetyl-L-carnitine against H-89-induced spatial memory deficits. METHODS: Spatial memory impairment was induced by the bilateral intrahippocampal administration of 10 µM H-89 (dissolved in dimethyl sulfoxide, DMSO) to rats. The rats then received bilateral administrations of either nicotine (1 µg/µL, dissolved in saline) or O-acetyl-L-carnitine (100 µM/side, dissolved in deionized water) alone and in combination. Control groups received either saline, deionized water, or DMSO. RESULTS: The H-89-treated animals showed significant increases in the time and distance travelled to find hidden platforms, and there was also a significant decrease in the time spent in the target quadrant compared to DMSO-treated animals. Nicotine and O-acetyl-L-carnitine had no significant effects on H-89-induced spatial learning impairments alone, but the bilateral intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevented H-89-induced spatial learning deficits and increased the time spent in the target quadrant in comparison with H-89-treated animals. CONCLUSIONS: Our results indicated the potential synergistic effects of nicotine and O-acetyl-L-carnitine in preventing protein kinase AII inhibitor (H-89)-induced spatial learning impairments.

A review on pain-relieving activity of berberine.

As isoquinoline alkaloid naturally occurs in Coptis and Berberis species, berberine (BER) has shown anti-oxidant, anti-tumour, anti-bacterial and hepatoprotective activities and beneficial effects against digestive, cardiovascular and neurological conditions. Also, BER antiinflammatory, pain-relieving and anti-cholinesterase activities were widely studied. The present overview discusses the analgesic effects of BER. Based on the literature, BER exerted pain-relieving activity against diabetic and chemotherapy-induced neuropathy, and sciatic nerve injury-induced pain via down-regulation of transient receptor potential vanilloid 1, suppression of NF-κB and modulation of µ and δ opioid receptors. Besides, BER could repress inflammatory markers tumour necrosis factor-α, interleukin-6 and IL-1ß, as well as prostaglandin E2, inducible nitric oxide synthase and cyclooxygenase-2. The modulatory effects of BER on dopamine and N-methyl d-aspartate systems were also noted. Moreover, BER could induce Nrf2 expression but inhibits p38-MAPK and STAT3 phosphorylation. Noteworthy, anti-cholinesterase activity, which may potentially contribute to BER analgesic properties, warrants particular attention.

Crocin: A fighter against inflammation and pain.

Crocin, a water-soluble carotenoid, is known as a pharmacologically active compound, particularly for its potent anti-oxidant activity. The present work provides a comprehensive review of the available literature concerning the anti-inflammatory properties of crocin in various organs/systems as well as its anti-nociceptive effects. PubMed, Scopus, and Web of Science electronic databases were systematically searched up to 28 March 2020 to detect all relevant preclinical and human studies in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. In total, 104 studies were included for qualitative synthesis. This systematic search and review indicated that crocin not only combats reactive oxygen species production and suppresses pro-inflammatory cytokines secretion but also alleviates inflammation in various organs (e.g. the lung, heart, brain, and kidney), in a series of animal models and in vitro experiments, via regulating mainly NF-κB pathway and NF-κBp65 translocation to the cell nucleus. In this context, modulation of PI3K/Akt appears to be a favorable crocin target contributing to NF-κB pathway inhibition. Even though data is limited in humans with only one clinically relevant study retrieved, the results of preclinical studies regarding anti-inflammatory/anti-nociceptive effects of crocin are promising and warrant further testing in clinical settings.

Anti-hypertensive effect of crocin and hesperidin combination in high-fat diet treated rats.

Cardiovascular diseases are the leading cause of death worldwide. Hypertension is the most important cause of such conditions. The use of medicinal herbs is of particular importance due to their lower cost and side effects. The aim of the present study was to compare the effect of hesperidin (HES) and crocin (CRO) alone and in combination, on blood pressure in a rat model of high-fat diet (HFD)-induced hypertension, using invasive carotid artery measurements. Animals were randomly assigned to the following groups: control group (received standard chow diet), HFD control group (received HFD containing 32% kcal of fat and 0.1% cholesterol), and three groups of HFD-treated animals that were treated with a single dose of CRO (20 mg/kg), HES (20 mg/kg), or CRO + HES (20 + 20 mg/kg). Except for the control group, rats received HFD for 7 weeks. On day 50, CRO, HES and normal saline were administered intraperitoneally and carotid arteries of the rats were cannulated. Three hours after the carotid artery cannulation, mean arterial blood pressure (MAP), systolic and diastolic blood pressure (SBP and DBP), and heart rate (HR) were measured using an intra-arterial catheter with the use of a Power Lab system. Data was analyzed using SPSS software. Rats that received HFD for 49 days presented a significant increase in SBP, HR and MAP compared to the control group (P<0.001). Whereas, HFD-treated rats of the CRO + HES group showed lower levels of SBP, HR and MAP; however, DBP remained unaffected. HES administration in HFD treated rats resulted in a significant decrease in SBP compared to the HFD control group with no significant differences in MAP. The hypotensive effects of the simultaneous administration of CRO and HES in HFD-hypertensive rats suggest the need for further study of these two natural products as a potential preventive measure against hypertension development, especially in patients with high normal blood pressure.

A review of the hepatoprotective effects of hesperidin, a flavanon glycoside in citrus fruits, against natural and chemical toxicities.

OBJECTIVES: Liver is the most important and functional organ in the body to metabolize and detoxify endogenous compounds and xenobiotics. The major goal of the present narrative review is to assess the hepatoprotective properties of hesperidin against a variety of natural and chemical hepatotoxins via different mechanisms. EVIDENCE ACQUISITION: Scientific databases such as Scopus, Medline, Web of Science and Google scholar were thoroughly searched, based on different keywords. RESULTS: A variety of natural hepatotoxins such as lipopolysaccharide, concanavalin A and microcystins, and chemical hepatotoxins such as ethanol, acrylamide and carbon tetrachloride have been shown to damage hepatocytes as well as other liver cells. In addition to hepatocytes, ethanol can also damage liver hepatic stellate cells, Kupffer cells and sinusoidal endothelial cells. In this regard, the flavanone hesperidin, occur in the rind of citrus fruits, had been demonstrated to possess widespread pharmacological properties. Hesperidin exerts its hepatoprotective properties via different mechanisms including elevation in the activities of nuclear factor-like 2/antioxidant response element and heme oxygenase 1 as well as the levels of enzymatic and non-enzymatic antioxidants. Furthermore, reduction in the levels of high-mobility group box 1 protein, inhibitor of kappa B protein-alpha, matrix metalloproteinase-9 and C-reactive protein are some other important hesperidin-derived hepatoprotective mechanisms. CONCLUSION: Based on several research papers, it could be concluded that hesperidin is able to protect against liver damage from inflammation and/or oxidative stress-mediated natural and chemical toxins.

The regulatory role of curcumin on platelet functions.

Curcumin, the main ingredient of Curcuma longa L., has been used as a spice and as a herbal medicine with different therapeutic characteristics for centuries in Asian countries. This phytochemical has been shown to possess beneficial antiplatelet activity that has introduced it as a promising candidate for the treatment of thromboembolism, atherothrombosis, and inflammatory diseases. Platelet dysfunction under different circumstances may lead to cardiovascular disease, and curcumin has been shown to have beneficial effects on platelet dysfunction in several studies. Therefore, this narrative review is aimed to summarize available evidence on the antiplatelet activity of curcumin and related molecular mechanisms for this activity.

Neuro-Protective Effects of Resveratrol on Carbon Monoxide-Induced Toxicity in Male Rats.

Acute carbon monoxide (CO) poisoning causes neurotoxicity through induction of necrosis, apoptosis, lipid peroxidation and oxidative stress. Resveratrol (RES) is a natural polyphenolic phytoalexin that exhibits neuroprotective effects in ischemia/reperfusion due to its anti-apoptotic, anti-necrotic and strong anti-oxidant properties as well as its ability to activate pro-survival pathways. In this study, rats were exposed to CO 3000 ppm for 1 h. Immediately after poisoning and on the next four consecutive days, RES (1, 5 and 10 mg/kg) was administered intraperitoneally. On the fifth day, animals' brains were excised, and necrosis, lipid peroxidation level and the level of Akt, BAX and BCL2 expression were evaluated. The results showed that RES 10 mg/kg significantly reduced lipid peroxidation, but RES 1 and 5 mg/kg had no significant effect on this parameter. Furthermore, RES 5 and 10 mg/kg significantly increased Akt expression level, while BAX/BCL2 ratio was reduced by RES 1, 5 and 10 mg/kg. Moreover, RES reduced necrotic foci in the brain, but the best results were seen following treatment with RES 10 mg/kg. In summary, RES showed neuroprotective effect in CO-poisoned rats as it decreased necrosis and BAX/BCL2 ratio and increased Akt expression levels. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of luteolin and luteolin-morphine co-administration on acute and chronic pain and sciatic nerve ligated-induced neuropathy in mice.

Background Neuropathic pain (NP) is a common condition accompanied by nerve injury. To date, there is no definite treatment approved for this disorder. In addition, many drugs that are used for NP cause adverse reactions. Luteolin is a naturally occurring flavonoid with diverse pharmacological properties such as anti-inflammatory, antioxidant and anticancer. We sought to investigate luteolin effects on chronic, acute and neuropathic pain as well as its potential to increase morphine anti-nociceptive effects in mice. Methods Albino mice (20-25 g) were randomly divided into 14 groups (n=7) including morphine 1 mg/kg body weight +luteolin (5 mg/kg body weight), morphine (9 mg/kg body weight, i.p.), luteolin (2.5, 5 and 10 mg/kg body weight), imipramine 40 mg/kg body weight and normal saline (NS) (0.9 %) as vehicle and subjected to hot plate test. Formalin test was done in the following groups: NS, diclofenac sodium (10 mg/kg body weight, i.p.), morphine (9 mg/kg body weight, i.p.) and luteolin (2.5, 5 and 10 mg/kg body weight). Results Administration of luteolin single dose (5 and 10 mg/kg body weight) significantly reduced neuropathic pain ( p<0.05$\rm{p}<0.05$) in comparison to negative control. Anti-nociceptive effects of luteolin were comparable to imipramine as the standard positive control ( p<0.001$\rm{p}<0.001$). Co-administration of luteolin and morphine potentiated morphine 1 mg/kg body weight painkilling effects ( p<0.001$\rm{p}<0.001$). Conclusions Our results showed that luteolin alone reduces neuropathic pain. Furthermore, when co-administered with morphine 1 mg/kg body weight, luteolin potentiates morphine effects. Therefore, luteolin-morphine co-administration might be a valuable alternative for the conventional treatment.

Regulation of autophagy by some natural products as a potential therapeutic strategy for cardiovascular disorders.

Autophagy is a lysosomal degradation process through which long-lived and misfolded proteins and organelles are sequestered, degraded by lysosomes, and recycled. Autophagy is an essential part of cardiomyocyte homeostasis and increases the survival of cells following cellular stress and starvation. Recent studies made clear that dysregulation of autophagy in the cardiovascular system leads to heart hypertrophy and failure. In this manner, autophagy seems to be an attractive target in the new treatment of cardiovascular diseases. Although limited activation of autophagy is generally considered to be cardioprotective, excessive autophagy leads to cell death and cardiac atrophy. Natural products such as resveratrol, berberine, and curcumin that are present in our diet, can trigger autophagy via canonical (Beclin-1-dependent) and non-canonical (Beclin-1-independent) pathways. The autophagy-modifying capacity of these compounds should be taken into consideration for designing novel therapeutic agents. This review focuses on the role of autophagy in the cardioprotective effects of these compounds.

Cytotoxic effects of crocin on MOLT-4 human leukemia cells.

BACKGROUND: Among various naturally occurring compounds which have been extracted from Crocus sativus, crocin has shown different pharmacological effects i.e. neuroprotection and anti-tumor activity. METHODS: Here, crocin effects on human T-cell leukemia cell line, MOLT-4, were evaluated. In this study, we examined the effects of 24 and 48 h of crocin treatment (50, 250 and 500 µM) on the viability of MOLT-4 cell line. Moreover, probable apoptotic/necrotic outcomes, reactive oxygen species (ROS) production variations along with crocin treatment consequences on DNA, were investigated. RESULTS: Results from MTT assay demonstrated that 48-h crocin treatment at 500 µM, significantly reduced cell viability (p<0.01). DNA fragmentation was recorded to be significantly increased at higher doses of crocin following 24 and 48 h (p<0.01). According to our results, while apoptosis was detected at all concentrations, necrosis detected at the highest dose, only. In comparison with control, ROS production was reduced at 50 and 250 µM. CONCLUSIONS: In accordance with previous reports, crocin exhibited mild cytotoxic effects on a leukemia cell line which might be mediated through the increase of DNA fragmentation.