Effects of crocin analogs on ocular blood flow and retinal function

The Role of Oral Supplementation for the Management of Age-Related Macular Degeneration: A Narrative Review

The majority of neurodegenerative eye disorders occur with aging and significantly impair quality of life. Age-related macular degeneration (AMD) is the third most common cause of visual impairment and blindness worldwide. One of the most important elements in the pathophysiology of neurodegenerative eye disease is certainly oxidative stress, with neuroinflammation and ocular ischemia which may also be significant factors. Antioxidants, either by food or oral supplementation, may be able to mitigate the deleterious effects of reactive oxygen species that build as a result of oxidative stress, ischemia, and inflammation. Over the past few decades, a number of research works examining the potential adjuvant impact of antioxidants in AMD have been published. In fact, there is not only more and more interest in already known molecules but also in new molecules that can help clinicians in the management of this complex multifactorial disease, such as astaxanthin and melatonin. However, while some studies showed encouraging outcomes, others were conflicting. In addition, more and more attention is also being paid to nutrition, considered a pivotal key point, especially to prevent AMD. For this reason, the purpose of this review is to analyze the main antioxidant molecules currently used as oral supplements for AMD treatment, as well as the role of diet and food intake in this ocular disease, to better understand how all these factors can improve the clinical management of AMD patients.

Dietary carotenoids to improve hypertension

Hypertension is one of the major risk factors for cardiovascular diseases and the main reason for premature death in older adults. Although antihypertensive medications have been used frequently, hypertension prevalence has increased in the last decade. Lifestyle improvement is a cornerstone of hypertension prevention and control. High dietary consumptions of fruits and vegetables are linked to reduced risks of high blood pressure. Carotenoids are natural tetraterpene pigments produced by bacteria, fungi, algae, some animals, and various plants. Because of their high pharmacological potential and safety, they have been mentioned as unique therapeutic agents for a diverse range of diseases. Carotenoids modulate high blood pressure. They also have several additional benefits for the cardiovascular system, including antioxidative, anti-inflammatory, anti-atherogenic, and antiplatelet effects. They improve endothelial function and metabolic profile, as well. In the present article, we reviewed the literature data regarding carotenoids' influence on hypertension in both preclinical and clinical studies. Furthermore, we reviewed the underlying mechanisms associated with antihypertensive properties derived from in vitro and in vivo studies. Suppressing reactive oxygen species (ROS) production, Inhibiting angiotensin-II, endothelin-1, and oxidized low-density lipoprotein; and also nitric oxide enhancement are some of the mechanisms by which they lower blood pressure. The present article indicated that astaxanthine, β-carotene, bixin, capsanthin, lutein, crocin, and lycopene have antihypertensive properties. Having significant antioxidant properties, they can decrease high blood pressure and concomitant comorbidities.

Review of Evidence for the Usage of Antioxidants for Eye Aging

Oxidative stress is one of the common factors leading to age-related eye diseases in older adults. Factors such as high oxygen consumption, high concentration of polyunsaturated fatty acids, and cumulative exposure to high-energy visible light in the eyes, lead to excessive generation of reactive oxygen species, hence triggering apoptosis of ocular cells and giving rise to ophthalmic diseases. Dietary supplements such as carotenoids, anthocyanins, and vitamins have antioxidant properties which may be of benefit in retaining better vision or reversing vision impairment; thus, studies have been conducted to understand the role of dietary supplements in the treatment or prevention of ophthalmic diseases. While high concentration of carotenoids such as lutein and zeaxanthin decrease the risk of developing age-related macular disease, anthocyanins and vitamins play a role in the treatment and prevention of other ophthalmic diseases: saffron extract reduced intraocular pressure in glaucoma patients; bilberry extract prevented impairments in lenses and retina, as well as alleviate symptoms of dry eye disease; high concentration of beta-carotene may reduce the risk of developing cataract. Further studies with clinical measurements are required to investigate the effectiveness of antioxidants on visual function and ophthalmic diseases.

Lipidomic analysis revealed n-3 polyunsaturated fatty acids suppressed choroidal thinning and myopia progression in mice

Myopia is increasing worldwide and its preventable measure should urgently be pursued. N-3 polyunsaturated fatty acids (PUFAs) have been reported to have various effects such as vasodilative and anti-inflammatory, which myopia may be involved in. This study is to investigate the inhibitory effect of PUFAs on myopia progression. A lens-induced myopia (LIM) model was prepared using C57B L6/J 3-week-old mice, which were equipped with a -30 diopter lens to the right eye. Chows containing two different ratios of n-3/n-6 PUFA were administered to the mice, and myopic shifts were confirmed in choroidal thickness, refraction, and axial length in the n-3 PUFA-enriched chow group after 5 weeks. To exclude the possibility that the other ingredients in the chow may have taken the suppressive effect, fat-1 transgenic mice, which can produce n-3 PUFAs endogenously, demonstrated significant suppression of myopia. To identify what elements in n-3 PUFAs took effects on myopia suppression, enucleated eyes were used for targeted lipidomic analysis, and eicosapentaenoic acid (EPA) were characteristically distributed. Administration of EPA to the LIM model confirmed the inhibitory effect on choroidal thinning and myopia progression. Subsequently, to identify the elements and the metabolites of fatty acids effective on myopia suppression, targeted lipidomic analysis was performed and it demonstrated that metabolites of EPA were involved in myopia suppression, whereas prostaglandin E2 and 14,15-dihydrotestosterone were associated with progression of myopia. In conclusion, EPA and its metabolites are related to myopia suppression and inhibition of choroidal thinning.

The Functional Vision Restorative Effect of Crocin via the BDNF-TrkB Pathway: An In Vivo Study

Abnormal dislocation of cone opsin protein affects the sensitivity function of photoreceptors and results in depressed central vision. Nutraceutical therapy is needed to restore the residual function of photoreceptors. Crocin is a natural substance for retinal health. However, its effect on the restoration of functional vision and its underlying mechanisms have not been fully studied. This study analyzed the restorative effect of crocin on residual functional vision in vivo in a mouse model. High-energy light-evoked photoreceptor dysfunction was confirmed by M opsin dislocation in the retina accompanied by a loss of functional vision. Crocin treatment significantly increased brain-derived neurotrophic factor (BDNF) protein in retinas, thus contributing to the re-localization of the M opsin protein, restoration of the visual acuity (VA), and high spatial frequency-characterized visual contrast sensitivity function (VCSF). In contrast, such effects were significantly reversed after the washout period. Additionally, the restorative effect of crocin on functional vision and M opsin re-localization can be reversed and blocked by synchronous injection of a tropomyosin receptor kinase B (TrkB) receptor antagonist (ANA-12). This study demonstrated the major functional vision-rescuing or restoring effect of crocin in vivo by modulating M opsin location plasticity and increasing the capacity of the residual photoreceptor function through the BDNF-TrkB receptor pathway.

Crocin as a vision supplement

Crocin is a natural ingredient of saffron (Crocus sativus L.) flower that has shown potential for application as a supplement in eye health and preserving vision. Crocin has been examined for its potential to treat various eye diseases such as glaucoma, macular dystrophies, diabetic retinopathy, and age-related macular degeneration. This review briefly discusses the role of crocin in different eye diseases. The underlying pathophysiological pathways involved in the effect of crocin on ophthalmic diseases are also reviewed. Preclinical evidence shows the cytoprotective, antioxidative, anti-inflammatory, and blood-flow enhancing effects of crocin in retinal tissue. Crocin also affects the retinal pathologies by activating PI3K/Akt and inhibiting NF-κB signalling pathways. Clinical evidence suggests that crocin improves outcomes in patients with retinal degenerations, retinal dystrophies, and glaucoma. Overall, crocin can be suggested as a potential vision supplement in healthy populations and patients with eye diseases. However, more clinical studies with larger sample sizes and longer follow-up durations are needed to confirm the current evidence.

The Pharmacological Activities of Crocus sativus L.: A Review Based on the Mechanisms and Therapeutic Opportunities of its Phytoconstituents

Crocus species are mainly distributed in North Africa, Southern and Central Europe, and Western Asia, used in gardens and parks as ornamental plants, while Crocus sativus L. (saffron) is the only species that is cultivated for edible purpose. The use of saffron is very ancient; besides the use as a spice, saffron has long been known also for its medical and coloring qualities. Due to its distinctive flavor and color, it is used as a spice, which imparts food preservative activity owing to its antimicrobial and antioxidant activity. This updated review discusses the biological properties of Crocus sativus L. and its phytoconstituents, their pharmacological activities, signaling pathways, and molecular targets, therefore highlighting it as a potential herbal medicine. Clinical studies regarding its pharmacologic potential in clinical therapeutics and toxicity studies were also reviewed. For this updated review, a search was performed in the PubMed, Science, and Google Scholar databases using keywords related to Crocus sativus L. and the biological properties of its phytoconstituents. From this search, only the relevant works were selected. The phytochemistry of the most important bioactive compounds in Crocus sativus L. such as crocin, crocetin, picrocrocin, and safranal and also dozens of other compounds was studied and identified by various physicochemical methods. Isolated compounds and various extracts have proven their pharmacological efficacy at the molecular level and signaling pathways both in vitro and in vivo. In addition, toxicity studies and clinical trials were analyzed. The research results highlighted the various pharmacological potentials such as antimicrobial, antioxidant, cytotoxic, cardioprotective, neuroprotective, antidepressant, hypolipidemic, and antihyperglycemic properties and protector of retinal lesions. Due to its antioxidant and antimicrobial properties, saffron has proven effective as a natural food preservative. Starting from the traditional uses for the treatment of several diseases, the bioactive compounds of Crocus sativus L. have proven their effectiveness in modern pharmacological research. However, pharmacological studies are needed in the future to identify new mechanisms of action, pharmacokinetic studies, new pharmaceutical formulations for target transport, and possible interaction with allopathic drugs.

Nutritional supplementation in the prevention and treatment of Glaucoma

Glaucoma is a chronic optic neuropathy that creates a significant burden on public health. Oxidative stress is hypothesised to play a role to glaucoma progression, and its reduction is being analysed as a therapeutic target. Dietary antioxidants play a crucial role in helping provide insight into this hypothesis. We reviewed 71 trials, interventional, I -vivo and I -vitro, including 11 randomised controlled trials, to determine if adjunctive nutritional supplementation could lead to a reduction in oxidative stress and prevent glaucomatous progression. Many laboratory findings show that vitamins and natural compounds contain an abundance of intrinsic antioxidative, neuroprotective and vasoprotective properties that show promise in the treatment and prevention of glaucoma. Although there is encouraging early evidence, most clincial findings are inconclusive. The group of B vitamins appear to have the greatest amount of evidence. Other compounds such as flavonoids, carotenoids, curcumin, saffron, CoQ10, Ggngko Biloba and Resveratrol however warrant further investigation in glaucoma patients. Studies of these antioxidants and other nutrients could create adjunctive or alternative preventative and treatment modalities for glaucoma to those currently available.

Pharmacological Effects of Saffron and its Constituents in Ocular Disorders from in vitro Studies to Clinical Trials: A Systematic Review

Introduction:

Some medicinal plants have shown promising therapeutic potential for the management of the diseases. We aimed to systematically review the literature wherein the therapeutic effects of saffron have been studied on eye disorders.

Methods

A systematic literature search was performed in PubMed, Scopus, Web of Science, Google scholar and other databases using eye disorders and saffron as key terms. No strict inclusion criteria were defined, and almost all clinical studies, as well as in vivo and in vitro studies were included. The reported data in each study were extracted and then qualitatively described.

Results

Finally, 78 articles were found but only 29 relevant articles were included. Nine articles were clinical trials and 20 articles were studies conducted on cellular and molecular aspects of saffron on eye disorders. According to the included studies, crocin prevented the pro-inflammatory response in retinal cells and decreased glucose levels in diabetic mice. Also, crocetin prevented retinal degeneration and saffron protected photoreceptors from light-induced damage in retinal cells. Saffron also improved visual function in age-related macular edema and decreased intraocular pressure in patients with glaucoma. In addition, it was shown that crocin can improve best corrected visual acuity and decrease central macular thickness in patients with diabetic maculopathy.

Conclusion

The results of this review indicated that saffron and its main ingredients such as crocin could be a potential candidate for the treatment of ocular disease especially eye inflammation; however, further clinical studies are needed to confirm such efficiency.

Medicinal plants and natural products as neuroprotective agents in age-related macular degeneration

The retina may suffer neurodegenerative damages, as other tissues of the central nervous system do, and serious eye diseases may develop. One of them is age-related macular degeneration, which causes progressive loss of vision due to retina degeneration. Treatment of age-related macular degeneration focuses on antioxidant agents and anti-vascular endothelial growth factor compounds, among others, that prevent/diminish oxidative stress and reduce neovascularisation respectively. The phytochemicals, medicinal plants and/or plant-diet supplements might be a useful adjunct in prevention or treatment of age-related macular degeneration owing to their antioxidant and anti-vascular endothelial growth factor properties. This review article presents the most investigated plants and natural products in relation to age-related macular degeneration, such as saffron, ginkgo, bilberry and blueberry, curcuma or turmeric, carotenoids, polyphenols, and vitamins C and E. This study provides up-to-date information on the effects, treatments, safety and efficiency of these phytotherapy products.

Natural Products: Evidence for Neuroprotection to Be Exploited in Glaucoma

Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.

Protective antioxidant effects of saffron extract on retinas of streptozotocin-induced diabetic rats

Objective: Oxidative stress plays an important role in the pathogenesis of diabetic retinopathy. The aim of the present study was to investigate the effect of Crocus sativus L. styles (saffron) extract on oxidative stress indices of retina in streptozotocin (STZ)-induced diabetic rats. Methods: Adult male Wistar rats (n=20) were randomized into the following 4 groups (n=6-7/ group): Control group (C): normal, Control + Saffron group (CS): non-diabetic rats treated with 60 mg/ kg of saffron extract, Diabetic group (D) and Diabetic + Saffron group (DS): diabetic rats treated with 60 mg/ kg saffron extract. We determined the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) as markers of antioxidant response, as well as malondialdehyde (MDA) as a marker of lipid peroxidation. Results: Induction of diabetes caused a significant decline in the activities of CAT (76.43%), SOD (53.43%) and GPx (77.58%). MDA levels were significantly lower in the DS group (0.878 ± 0.375 nmol MDA/ mg protein) as compared to D group (1.950 ± 0.299 nmol MDA/ mg protein, p<0.01) and in the CS group (0.503 ± 0.221) in comparison to C group (1.699 ± 0.454, p<0.01). Moreover, SOD and GPx activities were significantly higher (more than 1.5 and 3.5-fold respectively) after treatment with saffron (p<0.01). Regarding the retinas of non-diabetic animals, the administration of the extract caused an > 1.8-fold increase in the activity of CAT (p<0.05) and a 3-fold decrease in MDA levels (p<0.01). Conclusions: This study showed that saffron extract has a protective antioxidant action in retinas of diabetic rats. Abbreviations: C = Control group, CS = non-diabetic rats diabetic rats treated with 60 mg/ kg saffron extract, D = diabetic group, DS = diabetic rats treated with 60 mg/ kg saffron extract, SOD = superoxide dismutase, GPx = glutathione peroxidase, CAT = catalase, MDA = malondialdehyde, DM = diabetes mellitus, DR = diabetic retinopathy, ROS = reactive oxygen species, STZ = streptozotocin, GSH = reduced glutathione.

Beneficial effects of saffron (Crocus sativus L.) in ocular pathologies, particularly neurodegenerative retinal diseases

Saffron (Crocus sativus L.) has been traditionally used in food preparation and as a medicinal plant. It currently has numerous therapeutic properties attributed to it, such as protection against ischemia, as well as anticonvulsant, antidepressant, anxiolytic, hypolipidemic, anti-atherogenic, anti-hypertensive, antidiabetic, and anti-cancer properties. In addition, saffron has remarkable beneficial properties, such as anti-apoptotic, anti-inflammatory and antioxidant activities, due to its main metabolites, among which crocin and crocetin stand out. Furthermore, increasing evidence underwrites the possible neuroprotective role of the main bioactive saffron constituents in neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, both in experimental models and in clinical studies in patients. Currently, saffron supplementation is being tested for ocular neurodegenerative pathologies, such as diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration and glaucoma, among others, and shows beneficial effects. The present article provides a comprehensive and up to date report of the investigations on the beneficial effects of saffron extracts on the main neurodegenerative ocular pathologies and other ocular diseases. This review showed that saffron extracts could be considered promising therapeutic agents to help in the treatment of ocular neurodegenerative diseases.

The feasibility of using Saffron to reduce the photosensitivity reaction of selected photosensitizers using red blood cells and staphylococcusAureus bacteria as targets

BACKGROUND

The photosensitivity reaction which appears after a Photodynamic therapy treatment session is a challenge that needs further investigation. The goal of this research is to evaluate the possibility of using saffron to reduce or control this photosensitivity reaction and to present mathematical modeling of the cell survival curves and their dependency on saffron concentration.

METHODS

Red blood cells (RBC) and Staphylococcus aureus Bacteria (STB) were used as targets in this study. The Photosensitivity of Rose Bengali, Methylene Blue, and Photofrin independently and incorporated with saffron was investigated for continued irradiation at different Saffron concentrations. Gompertz's function was used to fit the survival curve parameters. The 50% cell survival rate was fit to an empirical formula based on Saffron concentrations.

RESULTS

Saffron inhibits the photosensitivity reaction of the three photosensitizers and causes a significant increase in the 50% survival rate time (t₅₀) for RBC`s and STB. Saffron didn't show phototoxicity when incubated alone with RBC`s and STB. The survival curve parameters of the RBCs and STB showed a good fit to the Gompertz function. Saffron concentration is related to the RBC`s t₅₀ based on power dependency of 0.56, 0.38 and 0.31 for Photofrin, Methylene Blue and Rose Bengali respectively and 0.1 on STB for Rose Bengali.

CONCLUSION

Saffron can efficiently be used to reduce the photosensitivity reaction of Photosensitizers after a PDT treatment session. Gompertz function was found to be an appropriate mathematical model for survival rate curves. The t₅₀ and the saffron concentration are well related through a power dependence empirical formula.

Traditional and Modern Uses of Saffron (Crocus Sativus)

The Aromatic and Medicinal Plants sector has undergone a remarkable evolution, especially during the last decade. The global market is moving more and more towards products of natural origin. Indeed, of the 4200-existing plant in Morocco, 800 are listed as aromatic and medicinal plants. Among these plants, saffron is a source of income for many areas of Morocco. Saffron, the dried stigma of the Crocus sativus flower, is considered among the main terroir products of Morocco. Saffron has accompanied all civilizations, whether for its culinary role, for its quality of dye or its ancestral virtues rooted in folk medicine. This review highlights the main components of saffron, and the pharmacological activities that result from it and make this product a serious therapeutic hope. Then, a classification of uses of saffron was carried out according to its uses, traditional, pharmaceutical, cosmetic and perfumery without forgetting its use a spice incorporated in many dishes around the world.

Neuroprotective and Anti-Inflammatory Effects of a Hydrophilic Saffron Extract in a Model of Glaucoma

Glaucoma is a neurodegenerative disease characterized by the loss of retinal ganglion cells (RGCs). An increase in the intraocular pressure is the principal risk factor for such loss, but controlling this pressure does not always prevent glaucomatous damage. Activation of immune cells resident in the retina (microglia) may contribute to RGC death. Thus, a substance with anti-inflammatory activity may protect against RGC degeneration. This study investigated the neuroprotective and anti-inflammatory effects of a hydrophilic saffron extract standardized to 3% crocin content in a mouse model of unilateral, laser-induced ocular hypertension (OHT). Treatment with saffron extract decreased microglion numbers and morphological signs of their activation, including soma size and process retraction, both in OHT and in contralateral eyes. Saffron extract treatment also partially reversed OHT-induced down-regulation of P2RY12. In addition, the extract prevented retinal ganglion cell death in OHT eyes. Oral administration of saffron extract was able to decrease the neuroinflammation associated with increased intraocular pressure, preventing retinal ganglion cell death. Our findings indicate that saffron extract may exert a protective effect in glaucomatous pathology.

Pharmacological Properties of Crocetin and Crocin (Digentiobiosyl Ester of Crocetin) from Saffron

Functional plant foods and medicinal herbs provide a wide variety of natural products for new drug research and development. Crocetin and crocin (digentiobiosyl ester of crocetin) are the major bioactive ingredients of saffron which is used as a costly spice, food colorant and traditional herbal medicine. These particular carotenoids have gained much research attention for their extensive pharmacological activities. Following oral administration, crocetin is rapidly absorbed into the blood circulation and widely distributed into the extra-vascular tissues of the body, whereas the water-soluble compound crocin is hardly absorbed through the gastrointestinal tract. Crocetin and crocin have been shown to be effective in the prevention and/or treatment of several diseases such as atherosclerosis, myocardial ischemia, hemorrhagic shock, cancer and cerebral injury. The compounds exert their biological and pharmacological effects largely through their strong antioxidant activity. However, there seems to be substantial variation in the effectiveness of both phytochemicals when used in different diseases. The aim of this review is to discuss the pharmacokinetic and medicinal properties of crocetin and crocin based on related literature and our research results.

Saffron (Crocus sativus L.) in Ocular Diseases: A Narrative Review of the Existing Evidence from Clinical Studies

Saffron (Crocus sativus L.) and its main constituents, i.e., crocin and crocetin, are natural carotenoid compounds, which have been reported to possess a wide spectrum of properties and induce pleiotropic anti-inflammatory, anti-oxidative, and neuroprotective effects. An increasing number of experimental, animal, and human studies have investigated the effects and mechanistic pathways of these compounds in order to assess their potential therapeutic use in ocular diseases (e.g., in age related macular degeneration, glaucoma, and diabetic maculopathy). This narrative review presents the key findings of published clinical studies that examined the effects of saffron and/or its constituents in the context of ocular disease, as well as an overview of the proposed underlying mechanisms mediating these effects.

Effects of Crocin on Diabetic Maculopathy: A Placebo-Controlled Randomized Clinical Trial

OBJECTIVE

Diabetic macular edema (DME) is one of the most important sight-threatening complications in patients with diabetes. Owing to neuroprotective properties, crocin, as the main constituent in saffron, is thought to be useful in the treatment and prevention of diabetic maculopathy. The aim of this trial was to evaluate the effects of crocin as a supplement on reducing inflammation in patients with diabetic maculopathy.

DESIGN

Double-masked, placebo controlled, phase 2 randomized clinical trial.

METHODS

Participants: In this study, 101 eyes of 60 patients with refractory diabetic maculopathy to conventional therapy including macular photocoagulation and intravitreal injection of anti-vascular endothelial growth factor agent (bevacizumab) with or without steroid (triamcinolone) were studied in 3 groups.

INTERVENTION

Patients in the crocin groups received 5 mg or 15 mg crocin tablets per day for 3 months, whereas patients in the placebo group received 1 placebo tablet per day during the study. The best-corrected visual acuity (BCVA) and central macular thickness (CMT) were measured before, every month during, and 3 months after intervention. Biochemical blood tests were also evaluated before and after trial.

MAIN OUTCOME MEASURES

The BCVA and CMT were evaluated as the primary outcomes, whereas HbA1c and fasting blood sugar (FBS) were studied as the secondary outcomes in this trial.

RESULTS

One hundred and one eyes were enrolled in this trial and were divided into 3 groups (crocin 5 mg, n = 34; crocin 15 mg, n = 33; and placebo, n = 34). According to our data, administration of crocin 15 mg tablet per day could significantly decrease HbA1c (P value = .024; 95% confidence interval [CI] 0.3-0.96), and CMT (P value = .005; 95% CI, 32.75-126.99) and improve BCVA (logMAR changes; P value = .012; 95% CI, 0.23-0.69) compared to the placebo group. Although administration of crocin 5 mg tablet per day could clinically improve HbA1c, FBS, CMT, and BCVA, the difference was not significant compared to the placebo group.

CONCLUSION

This study indicated the effect of crocin as a potent antioxidant and neuroprotective for treatment of refractory DME in the short term; however, the clinical significance is yet to be proved in a study with larger sample size and longer duration of follow-up and also in treatment-naïve patients.

A comprehensive review on regulatory effects of crocin on ischemia/reperfusion injury in multiple organs

Ischemia-reperfusion (I/R) injury affects o₂-dependent organs including liver, kidneys, heart, brain, and intestine. I/R injury is described as the cellular injury in an organ caused by ischemia and then further aggravated during the reperfusion due to intracellular alterations. It is a process that happens in clinical settings such as organ transplantation, reperfusion after thrombolytic therapy, and coronary angioplasty. Crocus sativus L. known as saffron used in folk medicine for its beneficial effects. It contains multiple bioactive compounds including the crocin, crocetin, picrocrocin, and safranal. Crocin, a water-soluble carotenoid has antitumor, radical scavenging, anti hyperlipidemia and memory improving effects. Moreover, crocin has antioxidant, and protective effects on I/R models in rats at various organs such as heart, brain, kidney, stomach, liver, and kidney as described in detail in this review.

A comprehensive review of the pharmacological potential of Crocus sativus and its bioactive apocarotenoids

Crocus sativus is an herbaceous plant that belongs to family Iridaceae. It is commonly known as saffron and has been used for medicinal purposes since many centuries in India and other parts of the world. Saffron of commercial importance comprises of dried stigmas of the plant and is rich in flavonoids, vitamins, and carotenoids. Carotenoids represent the main components of saffron and their cleavage results in the formation of apocarotenoids such as crocin, picrocrocin, and safranal. Studies conducted during the past two decades have revealed the immense therapeutic potential of saffron. Most of the therapeutic properties are due to the presence of unique apocarotenoids having strong free radical scavenging activity. The mode of action of these apocarotenoids could be: modulatory effects on detoxifying enzymes involved in combating oxidative stress, decreasing telomerase activity, increased the proapoptotic effect, inhibition of DNA, RNA and protein synthesis, and by a strong binding capacity of crocetin with tRNA. The present review focuses on the therapeutic role of saffron and its bio oxidative cleavage products and also highlights the possible molecular mechanism of action. The findings reported in this review describes the wide range of applications of saffron and attributes its free radical scavenging nature the main property which makes this spice a potent chemotherapeutic agent for the treatment of various diseases.

Neuroprotection in Glaucoma: Old and New Promising Treatments

Glaucoma is a major global cause of blindness, but the molecular mechanisms responsible for the neurodegenerative damage are not clear. Undoubtedly, the high intraocular pressure (IOP) and the secondary ischemic and mechanical damage of the optic nerve have a crucial role in retinal ganglion cell (RGC) death. Several studies specifically analyzed the events that lead to nerve fiber layer thinning, showing the importance of both intra- and extracellular factors. In parallel, many neuroprotective substances have been tested for their efficacy and safety in hindering the negative effects that lead to RGC death. New formulations of these compounds, also suitable for chronic oral administration, are likely to be used in clinical practice in the future along with conventional therapies, in order to control the progression of the visual impairment due to primary open-angle glaucoma (POAG). This review illustrates some of these old and new promising agents for the adjuvant treatment of POAG, with particular emphasis on forskolin and melatonin.

Effect of Saffron on Metabolic Profile and Retina in Apolipoprotein E-Knockout Mice Fed a High-Fat Diet

Saffron is a spice that has been traditionally used as a regimen for a variety of diseases due to its potent antioxidant attributes. It is well documented that impaired systemic oxidative status is firmly associated with diverse adverse effects including retinal damage. The aim of this study was to investigate the role of saffron administration against the retinal damage in apoE -/- mice fed a high-fat diet, since they constitute a designated experimental model susceptible to oxidative stress. Twenty-one mice were allocated into three groups: Group A (control, n = 7 c57bl/6 mice) received standard chow diet; Group B (high-fat, n = 7 apoE -/- mice) received a high-fat diet; and Group C (high-fat and saffron, n = 7 apoE -/- mice) received a high-fat diet and saffron (25 mg/kg/d) through their drinking water. The duration of the study was 20 weeks. Lipidemic profile, glucose, C-reactive protein (CRP), and total oxidative capacity (PerOX) were measured in blood serum. Histological analysis of retina was also conducted. Administration of saffron resulted in enhanced glycemic control and preservation of retinal thickness when compared with apoE -/- mice fed a high-fat diet. The outcomes of the study suggest the potential protective role of saffron against retinal damage induced by oxidative stress. Nevertheless, verification of these results in humans is required before any definite conclusions can be drawn.

Effect of Intraperitoneal Injection of Saffron on the Treatment of Experimental Endotoxin Induced Uveitis in the Rabbit

INTRODUCTION

Saffron with scientific name of "Crocus sativus" from the family "Iridaceae" is a plant without stem and root. Antioxidative and immunomodulatory effects of saffron has been demonstrated in different studies.

AIM

To assess the effects of saffron in the treatment on Lipopolysaccharide (LPS) induced uveitis in the rabbit.

MATERIALS AND METHODS

Thirty healthy female New Zealand white rabbits were prepared. LPS induced uveitis was confirmed via slit lamp examination 24 hours after intravitreal injection of Salmonella typhimurium LPS endotoxin in the right eye of all rabbits. Then the animals were randomly divided into two equal groups - group 1 (controls) and group 2 (saffron). After 24 hours of intravitreal injection of LPS, 60 mg/body weight of saffron was injected intraperitoneally for Group 2. On the seventh day after intraperitoneal injection, all rabbits of both groups were euthanized with an overdose intraperitoneal injection of sodium thiopental. Immediately after euthanasia, enucleation of both groups of rabbits was done. Clinical Scoring System (CSS) and pathological severity score of uveitis was assessed for each eye.

RESULTS

No statistical difference in the CSS was found in days 3,5, and 7 after intraperitoneal injection of saffron. Also, Pathological Severity Score (PSS) did not show a significant difference between two groups. Additionally, the maximum PSS of both groups was very closed but the number was observed in the saffron group (20%) more than control group (10%).

CONCLUSION

Intraperitoneal injection of saffron was ineffective in the management of experimental uveitis. Further studies with different dosages and follow up and using other routes of administration are needed.

Efficacy and Safety of Saffron Supplementation: Current Clinical Findings

Saffron (Crocus savitus) is a Middle-Eastern herb with strong antioxidant properties. Its major constituents, safranal, crocin, and crocetin, are also antioxidants and bear structural similarities to other well-known natural antixodant substances, such as zeaxanthin. Given the role of oxidative stress in many diseases, considerable interest has been shown into the potential role of saffron supplementation as a treatment for a range of diseases. In vitro and animal studies have provided evidence that saffron and its constituents may be potent therapies for a range of pathologies, including Alzheimer's disease, age-related macular degeneration (AMD) and cardiac ischemia. Whether these findings translate into clinical efficacy, however, has as of yet been incompletely assessed. This makes assessing the role of saffron supplementation in these diseases difficult. Here, we review the current human clinical evidence supporting saffron supplementation as a treatment for a range of pathologies and the underlying science supporting its use.

Review of Scientific Evidence of Medicinal Convoy Plants in Traditional Persian Medicine

One concept used in traditional Persian medicine (TPM) for multidrug therapy is that of the convoy drug (Mobadregh). According to TPM texts, convoy drugs are substances (or drugs), which facilitate the access of drugs or foods to the whole body or to specific organs. This study reviewed some convoy drugs presented in TPM, their biological effects, and their probable interactions with main drugs, considering the increased absorption through inhibition of P-glycoprotein (P-gp) efflux function, bioavailability-enhancing effects, and decreased metabolism of the main drug using electronic databases including PubMed, Scopus, ScienceDirect, and Google Scholar in November and December, 2013. Recent studies have proven the beneficial effects of Crocus sativus L. (saffron) and camphor on the heart and brain, the cerebral therapeutic effects of Asarum europaeum (hazelwort), the hepatoprotective effects of Cichorium intybus (chicory), and Apium graveolens (celery) seeds, and the diuretic effects of Cinnamomum zeylanicum (cinnamon), and Cucumis melo (melon) seeds. The effects of vinegar in targeting the liver and brain have also been demonstrated. An evaluation of the results demonstrated that the suggested convoy drugs, including Piper nigrum (black pepper), Piper longum (long pepper), red wine, Camellia sinensis (tea), hazelwort, Mentha longifolia (pennyroyal), Anethum graveolens (dill), Foeniculum vulgare (fennel), cinnamon, and Sassafras albidum (sassafras) can increase the bioavailability of coadministered drugs by inhibition of P-gp or cytochrome P450s (CYP450s) or both of them. This evidence could be a good basis for the use of these agents as convoys in TPM.

Natural Compounds from Saffron and Bear Bile Prevent Vision Loss and Retinal Degeneration

All retinal disorders, regardless of their aetiology, involve the activation of oxidative stress and apoptosis pathways. The administration of neuroprotective factors is crucial in all phases of the pathology, even when vision has been completely lost. The retina is one of the most susceptible tissues to reactive oxygen species damage. On the other hand, proper development and functioning of the retina requires a precise balance between the processes of proliferation, differentiation and programmed cell death. The life-or-death decision seems to be the result of a complex balance between pro- and anti-apoptotic signals. It has been recently shown the efficacy of natural products to slow retinal degenerative process through different pathways. In this review, we assess the neuroprotective effect of two compounds used in the ancient pharmacopoeia. On one hand, it has been demonstrated that administration of the saffron constituent safranal to P23H rats, an animal model of retinitis pigmentosa, preserves photoreceptor morphology and number, the capillary network and the visual response. On the other hand, it has been shown that systemic administration of tauroursodeoxycholic acid (TUDCA), the major component of bear bile, to P23H rats preserves cone and rod structure and function, together with their contact with postsynaptic neurons. The neuroprotective effects of safranal and TUDCA make these compounds potentially useful for therapeutic applications in retinal degenerative diseases.

Saffron and retina: neuroprotection and pharmacokinetics

Age-related macular degeneration (AMD) is a retinal neurodegenerative disease whose development and progression are the results of a complex interaction between genetic and environmental risk factors. Both oxidative stress and chronic inflammation play a significant role in the pathogenesis of AMD. Experimental studies in rats with light-induced photoreceptors degeneration demonstrated that saffron may protect photoreceptor from retinal stress, preserving both morphology and function and probably acting as a regulator of programmed cell death, in addition to its antioxidant and anti-inflammatory properties. Recently, a randomized clinical trial showed that in patients with early AMD, dietary supplementation with saffron was able to improve significantly the retinal flicker sensitivity suggesting neuroprotective effect of the compound. Here, we examine the progress of saffron dietary supplementation both in animal model and AMD patients, and discuss the potential and safety for using dietary saffron to treat retinal degeneration.

Bioactivity assessment and toxicity of crocin: a comprehensive review

Since ancient times, saffron, the dried stigma of the plant Crocus sativus L. has been extensively used as a spice and food colorant; in folk medicine it has been reputed to be efficacious for the alleviation and treatment of ailments. In addition to the three founded major constituents including crocin, picrocrocin and safranal, presence of carotenoids, carbohydrates, proteins, anthocyanins, vitamins and minerals provide valuable insights into the health benefits and nutritional value of saffron. Of the carotenoids present in saffron, highly water-soluble crocin (mono and diglycosyl esters of a polyene dicarboxylic acid, named crocetin) is responsible for the majority of its color, and appears to possess various health-promoting properties, as an antioxidant, antitumor, memory enhancer, antidepressant, anxiolytic and aphrodisiac. It is also worth noting that the crocin principle of saffron exhibited high efficacy along with no major toxicity in experimental models. We would be remiss to not consider the great potential of saffron and crocin, which benefits the cuisine and health of human life throughout the world. The present study provides a comprehensive and updated report of empirical investigations on bioactivities and biological characteristics of crocin.

Avicenna's (Ibn Sina) the Canon of Medicine and saffron (Crocus sativus): a review

In this review, we introduce the traditional uses of saffron and its pharmacological activities as described by either Avicenna in Book II, Canon of Medicine (al-Qanun fi al-tib) or from recent scientific studies. Modern pharmacological findings on saffron are compared with those mentioned in Avicenna's monograph. A computerized search of published articles was performed using MEDLINE, Scopus and Web of Science databases as well as local references. The search terms used were saffron, Crocus sativus, crocin, crocetin, safranal, picrocrocin, Avicenna and 'Ibn Sina'. Avicenna described various uses of saffron, including its use as an antidepressant, hypnotic, anti-inflammatory, hepatoprotective, bronchodilatory, aphrodisiac, inducer of labour, emmenagogue and others. Most of these effects have been studied in modern pharmacology and are well documented. The pharmacological data on saffron and its constituents, including crocin, crocetin and safranal, are similar to those found in Avicenna's monograph. This review indicates that the evaluation of plants based on ethnobotanical information and ancient books may be a valuable approach to finding new biological activities and compounds.

The effect of the extract of Crocus sativus and its constituent safranal, on lung pathology and lung inflammation of ovalbumin sensitized guinea-pigs

Different pharmacological effects of Crocus sativus have been demonstrated on guinea pig tracheal chains in previous studies. In the present study, the prophylactic effect of the extract of C. sativus and its constituent, safranal on lung pathology and total and differential white blood cells (WBC) of sensitized guinea pigs was examined. Guinea pigs were sensitized with injection and inhalation of ovalbumin (OA). One group of sensitized guinea pigs were given drinking water alone (group S) and three groups were given drinking water containing three concentrations of safranal (S+SA1, S+SA2 and S+SA3 groups), three groups, drinking water containing three concentrations of extract (S+CS1, S+CS2 and S+CS3 groups) and one group drinking water containing one concentration of dexamethasone (S+D group) (n=6, for all groups). The lung pathology was evaluated in control, non treated and treated sensitized groups. Total and differential WBC counts of lung lavage were also examined. All pathological indices in group S showed significant increased compared to control group (p<0.05 for lung congestion and p<0.001 for other groups). Total WBC number (p<0.001), eosinophyl percentage (p<0.001) in lung lavage and serum histamine levels (p<0.01) were also increased in sensitized animals compared to those of controls. Treatment of S animals with dexamethasone, all concentrations of the extract and safranal significantly improved lung pathological changes, most types of WBC and serum histamine levels compared to group S (p<0.05-0.001). Treatment of S group with first concentration of safranal also decreased total WBC. Treatment with safranal was more effective in improvement of most pathological changes, total and differential WBC count as well as serum histamine level (p<0.05-0.001). These results showed a preventive effect of the extract of C. sativus and its constituent safranal on lung inflammation of sensitized guinea pigs. The results also showed that the effect of the plant is perhaps due to its constituent safranal.

Crocetin: an agent derived from saffron for prevention and therapy for cancer

Cancer is one of the leading causes of death in the United States and accounts for approximately 8 million deaths per year worldwide. Although there is an increasing number of therapeutic options available for patients with cancer, their efficacy is time-limited and non-curative. Approximately 50-60% cancer patients in the United States utilize agents derived from different parts of plants or nutrients (complementary and alternative medicine), exclusively or concurrently with traditional therapeutic regime such as chemotherapy and/or radiation therapy. The need for new drugs has prompted studies evaluating possible anti-cancer agents in fruits, vegetables, herbs and spices. Saffron, a spice and a food colorant present in the dry stigmas of the plant Crocus sativus L., has been used as an herbal remedy for various ailments including cancer by the ancient Arabian, Indian and Chinese cultures. Crocetin, an important carotenoid constituent of saffron, has shown significant potential as an anti-tumor agent in animal models and cell culture systems. Crocetin affects the growth of cancer cells by inhibiting nucleic acid synthesis, enhancing anti-oxidative system, inducing apoptosis and hindering growth factor signaling pathways. This review discusses the studies on cancer preventive potential of crocetin and its future use as an anticancer agent.

The effect of Crocus sativus extract on human lymphocytes' cytokines and T helper 2/T helper 1 balance

The effects of macerated extracts of Crocus sativus (Family Iridaceae) (saffron) on cell viability and cytokine release of stimulated peripheral blood mononuclear cells by phytohemagglutinin (PHA) and nonstimulated cells were examined. The effects of three concentrations of macerated extract, dexamethasone, and saline on cell viability and production of cytokines, including interleukin (IL)-4, IL-10, and interferon-γ (IFN-γ) were evaluated. In cells stimulated with PHA, different concentrations of the extract significantly inhibited cell viability of lymphocytes (P<.001 for all concentrations). High concentrations of the extract (500 μg/mL) also inhibited secretion of IFN-γ in stimulated cells and IL-10 secretion in both stimulated and nonstimulated cells (P<.05 for all cases). The effects of high and low concentrations of the extract (500 and 50 μg/mL, respectively) on IL-4 secretion were lower than that of dexamethasone (P<.05 to P<.001). The extract showed a stimulatory effect on IFN-γ and IL-4 secretion in nonstimulated cells. The ratios of IFN-γ to IL-4 in the presence of all concentrations of saffron on stimulated cells were significantly higher than for the control group (P<.05 to P<.01). These results indicated that the extract of saffron leads to increased ratio of IFN-γ to IL-4.

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.

Effects of some natural flavonoids on retinal function recovery after ischemic insult in the rat

PURPOSE

There are six natural flavonoids studied recently and their effects on ocular blood flow measured with colored microsphere technique. It was found that three out of six compounds showed strong positive effects in increasing the ocular blood flow. In this study, we tried to find out whether these results can be translated on their effects to improve retinal function recovery after ischemic insult.

METHODS

Electroretinography was used to measure the b-wave recovery as an indication of retinal function recovery.

RESULTS

Naringenin, hesperetin, and rutin were found to produce marked positive effects on b-wave recovery, whereas naringin, hesperidin, and quercetin showed poor recovery of b-wave after ischemic insult of the retina.

CONCLUSION

It was found that the compounds that showed strong increase of ocular blood flow also showed marked increase of retinal function recovery, whereas those that showed poor increase of ocular blood flow also showed poor effects on the retinal function recovery.

Structure-activity relationship (SAR) between some natural flavonoids and ocular blood flow in the rabbit

PURPOSE

Flavonoids with two to five hydroxy groups, with or without sugar, and/or methoxy groups were studied on their effects to affect ocular blood flow.

METHODS

Colored microsphere technique was used to determine the ocular blood flow in rabbit eyes.

RESULTS

Flavonoids with three free hydroxy (OH) groups seemed to produce the optimal effects in increasing ocular blood flow (naringenin and hesperitin, Pfalts and Bauer, Waterbury, CT). Whether the OH groups are below three (naringenin, hesperitin, Pfalts and Bauer, Waterbury, CT) or above four (Quercetin, Pfalts and Bauer, Waterbury, CT), they produced no effects on the ocular blood flow. When OH groups are four (rutin, Aldrich, Milwaukee, WI), it produced mixed effects on ocular blood flow. The attachment of rutinose and/or methoxy group in the structure did not affect the ocular blood flow one way or the other.

CONCLUSION

The ocular blood flow is increased significantly by the number of OH group in the molecule, with three the best to increase the ocular blood flow.