Effects of saffron extract and its constituent crocin on learning behaviour and long-term potentiation

Reduction of metabolic and behavioral signs of acute stress in male Wistar rats by saffron water extract and its constituent safranal

CONTEXT

Saffron extract can inhibit the metabolic disorders induced by stress but the mechanism of action of saffron extract in the central nervous system is not clear.

OBJECTIVE

The present research investigated the effects of saffron water extract and its constituent, safranal on the behavioral and metabolic signs induced by electroshock stress in male Wistar rats (W: 250-300 g).

MATERIALS AND METHODS

Dried saffron material and maceration method was used for extraction. Animals received intra-amygdala (1, 5, and 10 µg/rat) or intraperitoneal (1, 5, and 10 mg/kg) administration of the extract, safranal (Fluka, Germany), or saline 5 or 30 min before stress induction, respectively.

RESULTS

The result showed that stress elevated the corticosterone plasma (115 nmol/L) concentration in the control and intra-amygdala (1, 5, and 10 µg/rat)-treated groups but not in groups that received extract or safranal (55 nmol/L) intraperitoneally (1, 5, and 10 mg/kg). Moreover, anorexia was reduced only in groups that received the extract (1, 5, and 10 mg/kg) or safranal (1, 5, and 10 mg/kg) intraperitoneally (50 sec). Stress increased sniffing, rearing, locomotion, and coping time, which were decreased by intraperitoneal (1, 5, and 10 mg/kg) but not by intra-amygdala (1, 5, and 10 µg/rat) administration of saffron extract and safranal.

DISCUSSION AND CONCLUSION

The results revealed that saffron water extract and safranal had an important impact on the reduction of both metabolic and behavioral signs of stress in male Wistar rats. Moreover, the involvement of the amygdala in this observation can be ruled out.

Psychological and neuroendocrinological effects of odor of saffron (Crocus sativus)

AIM

The purpose of this study was to clarify the effects of saffron odor on symptoms unique to women, such as premenstrual syndrome (PMS), dysmenorrhea (menstrual pain) and irregular menstruation.

MATERIALS AND METHODS

Thirty-five women with a normal sense of smell were exposed to saffron odor for 20 min. Saliva samples were then collected to measure levels of cortisol (C), testosterone (T) and 17-β estradiol (E) by enzyme immunoassay, and the State-Trait Anxiety Inventory (STAI) was administered as a psychological test.

RESULTS

Saffron odor significantly decreased C levels after short-term stimulation (20 min) in both follicular and luteal phases. E level after exposure to saffron odor was increased in both the follicular- and luteal-phase groups. STAI score decreased in the follicular and luteal phases in the saffron group.

CONCLUSIONS

The present findings support the existence of physiological and psychological effects of saffron odor in women. Our results indicate that saffron odor exert some effects in the treatment of PMS, dysmenorrhea and irregular menstruation. This is the first report to suggest that saffron odor may be effective in treating menstrual distress.

Saffron in the treatment of patients with mild to moderate Alzheimer's disease: a 16-week, randomized and placebo-controlled trial

WHAT IS KNOWN

Herbal medicines have been used in the treatment of behavioural and psychological symptoms of dementia but with variable response. Crocus sativus (saffron) may inhibit the aggregation and deposition of amyloid β in the human brain and may therefore be useful in Alzheimer's disease (AD).

OBJECTIVE

The goal of this study was to assess the efficacy of saffron in the treatment of mild to moderate AD.

METHODS

Forty-six patients with probable AD were screened for a 16-week, double-blind study of parallel groups of patients with mild to moderate AD. The psychometric measures, which included AD assessment scale-cognitive subscale (ADAS-cog), and clinical dementia rating scale-sums of boxes, were performed to monitor the global cognitive and clinical profiles of the patients. Patients were randomly assigned to receive capsule saffron 30 mg/day (15 mg twice per day) (Group A) or capsule placebo (two capsules per day) for a 16-week study.

RESULTS

After 16 weeks, saffron produced a significantly better outcome on cognitive function than placebo (ADAS-cog: F=4·12, d.f.=1, P=0·04; CDR: F=4·12, d.f.=1, P=0·04). There were no significant differences in the two groups in terms of observed adverse events.

WHAT IS NEW AND CONCLUSION

This double-blind, placebo-controlled study suggests that at least in the short-term, saffron is both safe and effective in mild to moderate AD. Larger confirmatory randomized controlled trials are called for.

Crocus sativus L.: A comprehensive review

Crocus sativus L. belonging to the family Iridaceae (syn - kesar) comprises the dried red stigma and is widely cultivated in Iran and other countries such as India and Greece. Saffron contains more than 150 volatile and aroma-yielding compounds mainly terpenes, terpene alcohol, and their esters. The bitter taste and an iodoform or hay-like fragrance are caused by chemicals picrocrocin and safranal. C. sativus possesses a number of medicinally important activities such as antihypertensive, anticonvulsant, antitussive, antigenototoxic and cytotoxic effects, anxiolytic aphrodisiac, antioxidant, antidepressant, antinociceptive , anti-inflammatory, and relaxant activity. It also improves memory and learning skills, and increases blood flow in retina and choroid. The present review explores the historical background, chemical constituents, pharmacological actions, uses, substitutes and adulterants, and toxicity. It also deals with its evaluation, formulations, and chemical tests in detail.

Crocin attenuates cisplatin-induced renal oxidative stress in rats

Reactive oxygen species (ROS) and oxidative damage are the most important factors in cisplatin-induced acute renal failure. This study examined the protective effects of crocin against cisplatin-induced renal oxidative stress in rat. Animals were divided into five groups (n=6). Group 1 received normal saline (2 ml/day, i.p.). Group 2 received a single dose of cisplatin (5mg/kg, i.p.). Groups 3-5 received crocin (100, 200, and 400mg/kg, i.p., respectively) for four consecutive days beginning 1-h before a single dose of cisplatin (5mg/kg) on day 1. On day 5, blood samples were drawn and kidneys were removed for histopathological, biochemical and RT-PCR examinations. Twenty four hours urinary chemistries were measured. Blood urea and creatinine and urinary glucose and protein concentrations in crocin-treated groups were significantly lower compared to the cisplatin-treated group. Histopathological studies showed massive damage in the S(3) segment of proximal tubules in cisplatin-treated group but not in crocin-treated groups. Crocin treatment resulted in a significant reduction in malondialdehyde (MDA) concentration and produced a significant elevation in total thiol and glutathione peroxidase concentrations. There was a significant elevation in the mRNA expression of glutathione peroxidase in crocin-treated groups. The results suggest that crocin attenuates cisplatin-induced renal oxidative stress in rats.

A 22-week, multicenter, randomized, double-blind controlled trial of Crocus sativus in the treatment of mild-to-moderate Alzheimer's disease

RATIONALE

There is increasing evidence to suggest the possible efficacy of Crocus sativus (saffron) in the management of Alzheimer's disease (AD).

OBJECTIVE

The purpose of the present investigation was to assess the efficacy of C. sativus in the treatment of patients with mild-to-moderate AD.

METHODS

Fifty-four Persian-speaking adults 55 years of age or older who were living in the community were eligible to participate in a 22-week, double-blind study of parallel groups of patients with AD. The main efficacy measures were the change in the Alzheimer's Disease Assessment Scale-cognitive subscale and Clinical Dementia Rating Scale-Sums of Boxes scores compared with baseline. Adverse events (AEs) were systematically recorded. Participants were randomly assigned to receive a capsule saffron 30 mg/day (15 mg twice per day) or donepezil 10 mg/day (5 mg twice per day).

RESULTS

Saffron at this dose was found to be effective similar to donepezil in the treatment of mild-to-moderate AD after 22 weeks. The frequency of AEs was similar between saffron extract and donepezil groups with the exception of vomiting, which occurred significantly more frequently in the donepezil group.

CONCLUSION

This phase II study provides preliminary evidence of a possible therapeutic effect of saffron extract in the treatment of patients with mild-to-moderate Alzheimer's disease. This trial is registered with the Iranian Clinical Trials Registry (IRCT138711051556N1).

Evaluation of Crocus sativus L. (saffron) on male erectile dysfunction: a pilot study

In this study, the effect of Crocus sativus (saffron) was studied on male erectile dysfunction (ED). Twenty male patients with ED were followed for ten days in which each morning they took a tablet containing 200mg of saffron. Patients underwent the nocturnal penile tumescence (NPT) test and the international index of erectile function questionnaire (IIEF-15) at the start of the treatment and at the end of the ten days. After the ten days of taking saffron there was a statistically significant improvement in tip rigidity and tip tumescence as well as base rigidity and base tumescence. ILEF-15 total scores were significantly higher in patients after saffron treatment (before treatment 22.15+/-1.44; after treatment 39.20+/-1.90, p<0.001). Saffron showed a positive effect on sexual function with increased number and duration of erectile events seen in patients with ED even only after taking it for ten days.

Stimulatory effect of Crocus sativus (saffron) on beta2-adrenoceptors of guinea pig tracheal chains

To study the mechanism(s) of the relaxant effects of Crocus sativus (Iridaceae), the stimulatory effect of aqueous-ethanolic extracts of this plant and one of its constituent, safranal was examined on beta-adrenoceptors in tracheal chains of guinea pigs. The beta(2)-adrenergic stimulatory was tested by performing the cumulative concentration-response curves of isoprenaline-induced relaxation of pre-contracted isolated guinea pig tracheal chains. The studied solutions were included two concentrations of aqueous-ethanolic extract from Crocus sativus (0.1 and 0.2g%), safranal (1.25 and 2.5 microg), 10nM propranolol, and saline. The study was done in two different conditions including: non-incubated (group 1, n=9) and incubated tissues with 1 microM chlorpheniramine (group 2, n=6). The results showed clear leftward shifts in isoprenaline curves obtained in the presence of only higher concentration of the extract in group 1 and its both concentrations in group 2 compared with that of saline. The EC(50) (the effective concentration of isoprenaline, causing 50% of maximum response) obtained in the presence of both concentrations of the extract (0.17+/-0.06 and 0.12+/-0.02) and safranal (0.22+/-0.05 and 0.22+/-0.05) in group 1 and only in the presence of two concentrations of the extract (1.16+/-0.31 and 0.68+/-0.21) in group 2 was significantly lower compared to saline (1.00+/-0.22 and 4.06+/-1.04 for groups 1 and 2, respectively) (p<0.05-0.001). The maximum responses obtained in the presence of both concentrations of the extract and safranal in group 1 were significantly lower than that of saline (p<0.005 for all cases). All values (CR-1=(EC(50) obtained in the presence of active substances/EC(50), obtained in the presence of saline)-1) obtained in the presence of higher concentrations of extract in group 1, its both concentrations and higher concentration of safranal in group 2 were negative and there were significant differences in this value between propranolol and those obtained in the presence of extract and safranal (p<0.05 to p<0.001). The results indicated a relatively potent stimulatory effect of the extract from Crocus sativus on beta(2)-adrenoceptors which is partially due to its constituent, safranal. A possible inhibitory effect of the plant on histamine (H(1)) receptors was also suggested.

Saffron in phytotherapy: pharmacology and clinical uses

Saffron (stigmata of Crocus sativus L.) has been used for medicinal purposes for millennia. Throughout history, uses against cancer and depressive mood can regularly be identified. These applications have also been in the focus of modern research. Promising and selective anti-cancer effects have been observed in vitro and in vivo, but not yet in clinical trials. Antidepressant effects were found in vivo and in clinical pilot studies. Saffron extracts thus have the potential to make a major contribution to rational phytotherapy.

Pharmacokinetic properties of crocin (crocetin digentiobiose ester) following oral administration in rats

This study investigated the pharmacokinetic properties of crocin following oral administration in rats. After a single oral dose, crocin was undetected while crocetin, a metabolite of crocin, was found in plasma at low concentrations. Simultaneously, crocin was largely present in feces and intestinal contents within 24h. After repeated oral doses for 6 days, crocin remained undetected in plasma and plasma crocetin concentrations were comparable to the corresponding data obtained after the single oral dose. Furthermore, the absorption characteristics of crocin were evaluated in situ using an intestinal recirculation perfusion method. During recirculation, crocin was undetected and low concentrations of crocetin were detected in plasma. The concentrations of crocin in the perfusate were reduced through different intestinal segments, and the quantities of drug lost were greater throughout the colon. These results indicate that (1) orally administered crocin is not absorbed either after a single dose or repeated doses, (2) crocin is excreted largely through the intestinal tract following oral administration, (3) plasma crocetin concentrations do not tend to accumulate with repeated oral doses of crocin, and (4) the intestinal tract serves as an important site for crocin hydrolysis.

Crocus sativus L. (petal) in the treatment of mild-to-moderate depression: a double-blind, randomized and placebo-controlled trial

Depression is a major worldwide health problem. Indeed, by 2020, depressive disorders are estimated to represent the second largest disease burden worldwide. Although a variety of pharmaceutical agents are available for the treatment of depression, psychiatrists find that many patients cannot tolerate the side effects, do not respond adequately, or finally lose their response. Our objective was to assess the efficacy of petal of Crocus sativus in the treatment of mild-to-moderate depression in a 6-week double-blind, placebo-controlled and randomized trial. Forty adult outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, fourth edition for major depression based on the structured clinical interview for DSM IV participated in the trial. In this double-blind, placebo-controlled and randomized trial, patients were randomly assigned to receive capsule of petal of C. sativus 30 mg/day (BD) (Group 1) and capsule of placebo (BD) (Group 2) for a 6-week study. At 6 weeks, petal of C. sativus produced a significantly better outcome on Hamilton Depression Rating Scale than placebo (d.f.=1, F=16.87, p<0.001). There were no significant differences in the two groups in terms of observed side effects. The results of this study indicate the efficacy of petal of C. sativus in the treatment of mild-to-moderate depression. A large-scale trial is justified.

Evaluation of the antitussive effect of stigma and petals of saffron (Crocus sativus) and its components, safranal and crocin in guinea pigs

The antitussive activity of Crocus sativus stigma and petal extracts and its components, safranal and crocin, was evaluated using the nebolized solution of citric acid 20% in guinea pigs. The extract and agents were injected intraperitoneally. The ethanolic extract of C. sativus (100-800 mg/kg) and safranal (0.25-0.75 ml/kg) reduced the number of cough. The ethanolic and aqueous extracts of petal and crocin did not show antitussive activity.

Anticonvulsant evaluation of safranal and crocin from Crocus sativus in mice

The anticonvulsant activities of Crocus sativus stigma constituents, safranal and crocin, were evaluated in mice using pentylenetetrazole (PTZ)-induced convulsions in mice. Safranal (0.15 and 0.35 ml/kg, i.p.) reduced the seizure duration, delayed the onset of tonic convulsions and protected mice from death. Crocin (200 mg/kg, i.p.) did not show anticonvulsant activity.

Hydro-alcoholic extract of Crocus sativus L. versus fluoxetine in the treatment of mild to moderate depression: a double-blind, randomized pilot trial

Depressive disorders are very common in clinical practice, with approximately 11.3 of all adults afflicted during any a year. Saffron is the world's most expensive spice and apart from its traditional value as a food additive, recent studies indicate several therapeutic effects for saffron. It is used for depression in Persian traditional medicine. Our objective was to compare the efficacy of hydro-alcoholic extract of Crocus sativus (stigma) with fluoxetine in the treatment of mild to moderate depression in a 6-week double-blind, randomized trial. Forty adult outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, fourth edition for major depression based on the structured clinical interview for DSM-IV and with mild to moderate depression participated in the trial. In this double-blind, single-center trial and randomized trial, patients were randomly assigned to receive capsules of saffron 30 mg/day (BD) (Group 1) and capsule of fluoxetine 20 mg/day (BD) (Group 2) for a 6-week study. Saffron at this dose was found to be effective similar to fluoxetine in the treatment of mild to moderate depression (F = 0.13, d.f. = 1, P = 0.71). There were no significant differences in the two groups in terms of observed side effects. The results of this study indicate the efficacy of Crocus sativus in the treatment of mild to moderate depression. A large-scale trial is justified.

Crocus sativus L. in the treatment of mild to moderate depression: a double-blind, randomized and placebo-controlled trial

Depression is a serious disorder in today's society, with estimates of lifetime prevalence as high as 21% of the general population in some developed countries. As a therapeutic plant, saffron is considered excellent for stomach ailments and as an antispasmodic, to help digestion and to increase appetite. It is also used for depression in Persian traditional medicine. Our objective was to assess the efficacy of the stigmas of Crocus sativus (saffron) in the treatment of mild to moderate depression in a 6-week double-blind, placebo-controlled and randomized trial. Forty adult outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition for major depression based on the structured clinical interview for DSM IV participated in the trial. Patients had a baseline Hamilton rating scale for depression score of at least 18. In this double-blind, placebo-controlled, single-centre and randomized trial, patients were randomly assigned to receive a capsule of saffron 30 mg[sol ]day (BD) (Group 1) or a capsule of placebo (BD) (Group 2) for a 6-week study. At 6 weeks, Crocus sativus produced a significantly better outcome on the Hamilton depression rating scale than the placebo (d.f. = 1, F = 18.89, p < 0.001). There were no significant differences in the two groups in terms of the observed side effects. The results of this study indicate the efficacy of Crocus sativus in the treatment of mild to moderate depression. A large-scale trial is justified.

Memory retrieval improvement by Ptychopetalum olacoides in young and aging mice

Amazonian peoples use traditional remedies prepared with Ptychopetalum olacoides (PO) roots for treating various age-related conditions. This study shows that a single intraperitoneally (i.p.) administration of Ptychopetalum olacoides ethanol extract (POEE, 50 and 100mg/kg) improved memory retrieval in step-down inhibitory avoidance (P <or= 0.05 and P <or= 0.01, test session latency 102 [19.38-300] and 192 [91.3-300]s, respectively versus control 24.7 [12.9-89.6]), without interfering with acquisition or consolidation in adult (2.5-month-old) mice. Comparable results were obtained with POEE given p.o. at 800 and 1000mg/kg (P <or= 0.05 and P <or= 0.01, 52.7 [19.5-297.2] and 85.7 [44.4-260.4] versus control 20.5 [8-92.6]). Moreover, memory amelioration was also observed (P <or= 0.01) in aging (14 months) mice presenting memory deficit (14.95 [10.8-41]) as compared to adult (2.5 months) mice (57 [15.7-141.2]), with the extract given acutely i.p. 100 mg/kg (300 [133.1-300] versus control 14.95 [10.8-41]) or p.o. 800 mg/kg (28.4 [15.1-84.6] versus control 11.5 [7.8-23.3]). Indeed, aging mice treated with POEE (800 mg/kg, p.o.) performed as well as adult mice. Consistently with its traditional use, the data suggest that POEE facilitates memory retrieval. Although the antioxidant and acetylcholinesterase inhibitory properties previously described for this extract may be of relevance, the molecular mechanism(s) underlying the improvement in memory retrieval here reported merit further scrutiny.

Comparison of Crocus sativus L. and imipramine in the treatment of mild to moderate depression: a pilot double-blind randomized trial [ISRCTN45683816]

BACKGROUND

The morbidity and mortality associated with depression are considerable and continue to increase. Depression currently ranks fourth among the major causes of disability worldwide, after lower respiratory infections, prenatal conditions, and HIV/AIDS. Crocus sativus L. is used to treat depression. Many medicinal plants textbooks refer to this indication whereas there is no evidence-based document. Our objective was to compare the efficacy of stigmas of Crocus sativus (saffron) with imipramine in the treatment of mild to moderate depression in a 6-week pilot double-blind randomized trial.

METHODS

Thirty adult outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition for major depression based on the structured clinical interview for DSM IV participated in the trial. Patients have a baseline Hamilton Rating Scale for Depression score of at least 18. In this double-blind, single-center trial, patients were randomly assigned to receive capsule of saffron 30 mg/day (TDS) (Group 1) and capsule of imipramine 100 mg/day (TDS) (Group 2) for a 6-week study.

RESULTS

Saffron at this dose was found to be effective similar to imipramine in the treatment of mild to moderate depression (F = 2.91, d.f. = 1, P = 0.09). In the imipramine group anticholinergic effects such as dry mouth and also sedation were observed more often that was predictable.

CONCLUSION

The main overall finding from this study is that saffron may be of therapeutic benefit in the treatment of mild to moderate depression. To the best of our knowledge this is the first clinical trial that supports this indication for saffron. A large-scale trial with placebo control is warranted.

Biomedical properties of saffron and its potential use in cancer therapy and chemoprevention trials

INTRODUCTION

Chemoprevention strategies are very attractive and have earned serious consideration as potential means of controlling the incidence of cancer. An important element of anticancer drug development using plants is the accumulation and analysis of pertinent experimental data and purported ethnomedical (folkloric) uses for plants. The aim of this review is to provide an updated overview of experimental in vitro and in vivo investigations focused on the anticancer activity of saffron (Crocus sativus L.) and its principal ingredients. Potential use of these natural agents in cancer therapy and chemopreventive trials are also discussed.

METHODS

A computerized search of published articles was performed using the MEDLINE database from 1990 to 2004. Search terms utilized including saffron, carotenoids, chemoprevention, and cancer. All articles were obtained as reprints from their original authors. Additional sources were identified through cross-referencing.

RESULTS

Studies in animal models and with cultured human malignant cell lines have demonstrated antitumor and cancer preventive activities of saffron and its main ingredients, possible mechanisms for these activities are discussed. More direct evidence of anticancer effectiveness of saffron as chemopreventive agent may come from trials that use actual reduction of cancer incidence as the primary endpoint

CONCLUSIONS

This work suggests that future research be warranted that will define the possible use of saffron as effective anticancer and chemopreventive agent in clinical trials.

Plants used in Chinese and Indian traditional medicine for improvement of memory and cognitive function

In traditional practices of Ayurvedic and Chinese medicine, numerous plants have been used to treat cognitive disorders, including neurodegenerative diseases such as Alzheimer's disease (AD). An ethnopharmacological approach has provided leads to identifying potential new drugs from plant sources, including those for cognitive disorders. Many drugs currently available in Western medicine were originally isolated from plants, or are derived from templates of compounds isolated from plants. Some anticholinesterase (anti-ChE) alkaloids isolated from plants have been investigated for their potential in the treatment of AD, and are now in clinical use. Galantamine, isolated from several plants including Lycoris radiata Herb., which was used in traditional Chinese medicine (TCM), is licensed in the United Kingdom for the treatment of mild to moderate AD. Various other plant species have shown pharmacological activities relevant to the treatment of cognitive disorders, indicating potential for therapeutic use in disorders such as AD. This article reviews some of the plants and their active constituents that have been used in traditional Ayurvedic medicine and TCM for their reputed cognitive-enhancing or antiageing effects. Plants and their constituents with pharmacological activities that may be relevant for the treatment of cognitive disorders, including enhancement of cholinergic function in the central nervous system (CNS), anti-inflammatory and antioxidant activities, are discussed.

Ethanol-induced suppression of LTP can be attenuated with an angiotensin IV analog

Hippocampal slices taken from animals chronically or acutely treated with ethanol exhibit significant inhibition of long-term potentiation (LTP). This inhibition appears to be associated with impaired activity of N-methyl-D-aspartate (NMDA) receptors, perhaps via ethanol-induced increases in GABAergic synaptic transmission. Recently, a role for the octapeptide angiotensin II (AngII) in ethanol's inhibition of LTP has been reported. Complementary to these findings our laboratory has shown that the application of the hexapeptide metabolite of AngII, angiotensin IV (AngIV), significantly facilitated normal tetanic-induced LTP in the hippocampal slice. This facilitation is presumably by activation of the angiotensin receptor subtype, AT(4). The present study tested whether an AT(4) receptor agonist could overcome ethanol-induced suppression of LTP. The results indicate that Nle(1)-AngIV could offset ethanol-induced suppression of LTP in the CA(1) region of the hippocampus. Pretreatment with the specific AT(4) receptor antagonist Nle(1), Leual(3)-AngIV blocked this facilitation implicating the involvement of the AT(4) receptor subtype. These results suggest that an AT(4) receptor agonist is effective in overcoming ethanol's suppressing influence on LTP, and encourage further investigation of the cognitive enhancing properties of such compounds.

The antioxidants alpha-lipoic acid and N-acetylcysteine reverse memory impairment and brain oxidative stress in aged SAMP8 mice

Oxidative stress may play a crucial role in age-related neurodegenerative disorders. Here, we examined the ability of two antioxidants, alpha-lipoic acid (LA) and N-acetylcysteine (NAC), to reverse the cognitive deficits found in the SAMP8 mouse. By 12 months of age, this strain develops elevated levels of Abeta and severe deficits in learning and memory. We found that 12-month-old SAMP8 mice, in comparison with 4-month-old mice, had increased levels of protein carbonyls (an index of protein oxidation), increased TBARS (an index of lipid peroxidation) and a decrease in the weakly immobilized/strongly immobilized (W/S) ratio of the protein-specific spin label MAL-6 (an index of oxidation-induced conformational changes in synaptosomal membrane proteins). Chronic administration of either LA or NAC improved cognition of 12-month-old SAMP8 mice in both the T-maze footshock avoidance paradigm and the lever press appetitive task without inducing non-specific effects on motor activity, motivation to avoid shock, or body weight. These effects probably occurred directly within the brain, as NAC crossed the blood-brain barrier and accumulated in the brain. Furthermore, treatment of 12-month-old SAMP8 mice with LA reversed all three indexes of oxidative stress. These results support the hypothesis that oxidative stress can lead to cognitive dysfunction and provide evidence for a therapeutic role for antioxidants.

Antinociceptive and anti-inflammatory effects of Crocus sativus L. stigma and petal extracts in mice

BACKGROUND

Crocus sativus L. (saffron) is used in folk medicine, for example as an antiedematogenic agent. We aimed to evaluate the antinociceptive and anti-inflammatory activity of saffron extracts in mice.

RESULTS

We used aqueous and ethanolic maceration extracts of Crocus sativus L. stigma and petals. Antinociceptive activity was examined using the hot plate and writhing tests. The effect of extracts against acute inflammation was studied using xylene induced ear edema in mice. The activity of the extracts against chronic inflammation was assessed by formalin-induced edema in the rat paw. In the hot plate tests, intraperitoneal injection of both extracts showed no significant antinociceptive activity in mice. The extracts exhibited antinociceptive activity against acetic acid induced writhing. Naloxone partially blocked only the antinociceptive activity of the stigma aqueous extract. Only the stigma extracts showed weak to moderate effect against acute inflammation. In chronic inflammation, both aqueous and ethanolic stigma extracts, as well as ethanolic petal extract, exerted anti-inflammatory effects.

CONCLUSIONS

We conclude that aqueous and ethanolic extracts of saffron stigma and petal have an antinociceptive effect, as well as acute and/or chronic anti-inflammatory activity.

Dietary flavonoids as potential neuroprotectants

There is an increasing awareness of the role of certain nutritional components, including dietary flavonoids found in fruit, vegetables and beverages, in the maintenance of health and prevention of chronic diseases. In this regard, recent studies highlight an exciting role with respect to their potential neuroprotective actions, in particular towards deficits commonly observed with aging, such as reduced performance of cognitive, memory and learning tasks. These neurological functions, and possible mechanisms involved in controlling them, can be influenced by supplementation of single dietary flavonoids, or as part of a flavonoid-rich preparation. With this, a renewed emphasis is aimed at further understanding their modes and sites of action. Moreover a common theme among many in vitro studies examining mechanisms of neuroprotection is the failure to include biologically relevant metabolites of the flavonoids known to enter the circulation, and thus most likely to be bioavailable to cells and tissues. This oversight will ultimately influence the mechanisms of action proposed to explain the neuroprotection observed in animals and human studies. As such, emerging findings suggest a variety of potential mechanisms of action of flavonoids and their bioavailable metabolites in cytoprotection against oxidative stress, which may be independent of conventional antioxidant reducing activities. Such mechanisms might involve their interaction with cell signalling cascades, their influence on gene expression and the down regulation of pathways leading to cell death.