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Arch Iran Med. March 2021;24(3):233-252
Review Article
Prospects of Saffron and its Derivatives in Alzheimer’s
Disease
Nadia Zandi, MD1; Benyamin Pazoki, MD1; Nazanin Momeni Roudsari, Pharm D2; Naser-Aldin Lashgari, Pharm D2; Vahid Jamshidi, PhD2;
Saeideh Momtaz, PhD3,4,5, Amir Hossein Abdolghaffari, PhD2,3,4,5*; Shahin Akhondzadeh, PhD6*
1Tehran University of Medical Sciences, Tehran, Iran
2Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
3Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran
4Toxicology and Diseases Group, Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), and
Department of Toxicology and Pharmacology, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
5Gastrointestinal Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
6Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
Received: September 17, 2019, Accepted: October 4, 2020, ePublished: March 1, 2021
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common form of dementia in the old age
population, making it a worldwide concern. Unfortunately, few drugs have been presented for treatment of mild and moderate
AD. To meet this need, more effective anti-AD agents are emerging. Accumulating evidence supports the beneficial roles of
natural-based products in brain function, neurotransmission, neurogenesis, synaptogenesis, and the prevention of amyloid
fibrillation and neuronal injury. Several in vitro, preclinical, and clinical studies suggest that saffron (its bioactive compounds) is
a potential nutraceutical with antioxidant, radical scavenging, anti-inflammatory, hypolipidemic, hypotensive, neuroendocrine,
and neuroprotective effects. It has also been proposed that saffron may delay the onset of AD, prevent its progression or help to
attenuate the symptoms of the disease. Therefore, we performed a comprehensive search on this plant and its derivatives for AD
treatment. Saffron and its active constituents interfere with AD by improving learning behavior, spatial memory, and cognitive
function; protecting against neuronal loss; inhibiting beta-amyloid aggregation and neurotoxicity; preventing senile plaques and
neurofibrillary tangle (NFT) formation; suppressing the acetylcholinesterase (AChE) activity; and reducing neuroinflammation.
Given conclusive scientific findings, saffron and its derivatives might counter neurodegenerative diseases through multiple
pathways. Further clinical trials are expected to confirm the neuroprotective properties of this herb and also to translate such
findings to improve patients’ outcomes.
Keywords: Acetylcholinesterase inhibitors, Amyloid beta, Apolipoprotein E, Neurofibrillary tangles, Saffron, Alzheimer’s disease
Cite this article as: Zandi N, Pazoki B, Momeni Roudsari N, Lashgari N, Jamshidi V, Momtaz S, et al. Prospects of saffron and its
derivatives in Alzheimer’s disease. Arch Iran Med. 2021;24(3):233–252. doi: 10.34172/aim.2021.35.
*Corresponding Author: Shahin Akhondzadeh, PhD; Psychiatric Research Center, Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, South Karr-
gar Street, Tehran, Iran. Email: s.akhond@neda.net
Amir Hossein Abdolghaffari, Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran, No.
99, Yakhchal, Gholhak, Shariati St., P. O. Box: 19419-33111, Tehran, Iran. Tel: +98 21 22640051-5, Fax: +98 21 22602059, Email: amirhosein172@hotmail.com
10.34172/aim.2021.35
doi
ARCHIVES OF
IRANIAN
MEDICINE
Introduction
Alzheimer’s disease (AD) is the main etiology of memory
loss, prompting irreversible progressive impairments
in cognition and memory.1 Both the incidence and
prevalence of AD are increasing worldwide. It is estimated
that in 2050, one out of 85 individuals will suffer from
AD.2 Thus far, several mechanisms have been proposed for
AD induction or progression. The cholinergic hypothesis
refers to reduction of acetylcholine (ACh) in the central
cortex of the brain – an area that involves functional
skills.3 Hence, acetylcholinesterase (AChE) inhibitors like
donepezil have been found effective in improving mild and
moderate to severe AD symptoms.3 The amyloid cascade
hypothesis (ACH) suggests a lack of balance between
production and clearance of amyloid-beta (Aβ), which
leads to nerve cell dysfunction and death.4 On the other
hand, intracellular neurofibrillary tangles (NFTs) block
neurotransmitters and cause neuronal cell death.5 Tau
oligomers are accumulated in β-sheet conformation and
produce NFTs.6 Also, high concentration of Aβ triggers
NFT formation, and accumulation of NFTs in neurons
lead to cell death.7 Another hypothesis points to the fact
that the ε4 and ε3 carriers of the apolipoprotein E gene
(APOE) are more prone to AD; notwithstanding, the ε4
allele is the main genetic risk factor for late-onset AD.
Apolipoprotein E (ApoE) is known to regulate lipid and
protein homeostasis in the brain.8-10 In addition to ApoE,
several other genes have also been implicated in AD such
as polymorphisms in sortilin related receptor 1 (SORL1),
clusterin, complement component receptor 1 (CCR1),
Cluster of differentiation 2 associated protein (CD2AP),
Cluster of differentiation 33 (CD33), Ephrin type-A
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Zandi et al
receptor 1 (EPHA1), and Membrane spanning 4-domains
A6E (MS4A4/MS4A6E) genes.11
Oxidative stress and free radicals are effective
factors for behavior and memory impairments in age-
related neurodegenerative disease.12 Genetic factors,13
neuroinflammation,14 type 2 diabetes, environmental
factors, stroke, and diet15,16 have also been proven to be
involved in AD onset and/or progression, although aging
is still the main risk factor for AD.17
Considering the shortcomings of current treatments
for late-onset AD and regarding the positive impact of
plant species in AD treatment (i.e. Melissa officinalis,
Nigella sativa, Boswellia spp. and Cinnamon spp.) natural
products are considered as high priorities for treatment of
neurodegenerative diseases.18 Saffron is one of the spices
extracted from stigmas of the Persian herb Crocus sativus
L. and is usually used in cooking19 and contains four main
constituents; safranal, crocin, crocetin, and picrocrocin.
Traditionally, saffron is used for gingival sedation,
catarrhal healing, expectoration, improving appetite and
digestion, nerve sedation and anticonvulsant, improving
sweating, and as antispasmodic.20,21 During the past two
decades, various clinical and experimental studies have
revealed that saffron and its bioactive constituents have
therapeutic functions as anticonvulsant, anti-hypertensive,
anti-spasmodic,22 cardioprotective, anti-atherosclerotic,23
anticancer,24 antidiabetic,25 antioxidant, antiparasitic,26
anti-inflammatory, analgesic,27 and immunomodulators.28
They might be involved in modulation of smooth muscles,29
gastrointestinal,30 respiratory,31 and reproductive32 systems.
Up to now, the majority of pharmacological experiments
on saffron and/or its components have focused on their
probable significant effects on CNS. The antidepressant,33
anticonvulsant,34 and antianxiety properties of saffron were
reported, while it may improve memory impairments,
tremor,35 opioid withdrawal syndrome,36 and was shown
to have a broad spectrum of protective effects on the
CNS. The stigmas, corms and phytochemicals of Crocus
sativus could improve neuronal impairments,37,38 such
as Parkinson’s disease, by reduction of dopamine in
the substantia nigra,39 suppression of neurotoxicity
by diminishing oxidative damage,40,41 repression of
neuroinflammation due to increased intraocular pressure
in order to avert retinal ganglion cell death in patients
with glaucoma,42 and improvement of neurodegenerative
retinal diseases43 and visual function in age-related macular
degeneration patients.44 In vivo, administration of saffron
improved memory impairment induced by ethanol,
aluminum (Al), morphine, ketamine, and arsenic.41,45-48
Extracts of saffron stigma have been presented to have
antioxidant and anti-amyloidogenic functions and also
inhibited Aβ aggregation and deposition.21,49
Active Constituents of Saffron
Phytochemical analysis showed that saffron contains nearly
150 volatile and some nonvolatile compounds, of which
only a few have already been identified. Apocarotenoid
glycosides (i.e. crocin); picrocrocin; volatile oil (i.e.
safranal); carotenoids; lycopene; alpha-, beta-, and gamma-
carotene; fatty oil and starch are the main constituents of
this plant.50 Crocin, and crocetin belong to carotenoids,
while picrocrocin and safranal are monoterpene aldehydes.
Crocin is a glucosyl ester of crocetin and the compound
responsible for the red color of Crocus sativus. However,
picrocrocin, a glycoside of safranal, provides the unpleasant
taste of Crocus sativus. Safranal is the main component
of saffron and is associated with its aroma.48 Crocin
and safranal isomers have bioactive properties for better
absorption in the intestinal lumen.51-53 It was shown that
saffron hydrolyzes to trans-crocetin by intestinal enzymes
immediately after the entrance to the lumen and absorbed
through the intestinal wall by passive diffusion.54,55 Crocin
is not absorbed orally, after a single dose or repeated doses,
but its oral administration produces a higher level of
crocetin in comparison with intravenous administration.56
However, crocin is highly detected in the intestinal tract
following oral administration. Crocin can hydrolyze to
crocetin when used orally, then the absorbed crocetin
is partially metabolized to mono- and di-glucuronide
conjugates.55,57 Crocetin’s affinity for binding to albumin
is low, which facilitates its transmission to different tissues
and helps to cross the blood brain barrier via transcellular
diffusion more easily.54,57,58 According to a recent study in
2019, fast intestinal absorption of saffron extracts leads to a
higher serum level of crocetin compared with intravenous
administration.59 The active components of saffron have
been shown to possess antidepressant and antitumor
effects, while they are able to neutralize free radicals and
reduce inflammation.20,21 Taken together, saffron might
be a candidate for research on neurodegenerative diseases.
Therefore, this review provides an overview of recently
published clinical, preclinical, and experimental studies
on therapeutic approaches using saffron and its derivatives
for different aspects of AD.
Amyloid-β, a Key Molecule in AD
There are three distinct types of amyloid beta including
very short oligomers, Aβ derived diffusible ligands, and
protofibrils. Amyloid precursor protein (APP) is produced
in the brain and is a major source of neurotoxic Aβ.60
In detail, β-site APP cleaving enzyme 1 (BACE1), the
main β-secretase in the brain, facilitates APP conversion
to C99
61,62 Later, Aβ is generated from C99 by activity of
γ-secretase. The γ-secretase function is regulated by
presenilin 1 and 2 (PSEN1, 2), and any mutation in these
proteins leads to excessive production of Aβ, initiating the
early onset of AD.63 In normal physiological states, there
is an equilibrium between the production and clearance of
Aβ in the brain,64 and any disturbance in Aβ elimination
or its overproduction will result in AD.62 Interestingly,
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Saffron and its Derivatives in Alzheimer’s Disease
low amounts of Aβ propitiously contribute to neural
development65 and can restrain lipoprotein oxidation
in cerebrospinal fluid (CSF).66 In addition, at low
concentrations, Aβ was shown to have neuronal protective
effects,67 whereas high levels of Aβ lead to neuronal
dysfunction by disrupting synaptic function and inducing
neurotoxicity through free radical formation. Free radicals
are accumulated in cerebral vessels, initiating a condition
called cerebral amyloid angiopathy (CAA). CAA is a
situation in which the amyloid proteins are placed through
cerebral blood vessel walls,68 which happens abundantly
in AD.64,69-71 Besides, accumulation of Aβ disrupts Ca
homeostasis in cells and induces excitotoxicity.72
Deposition of Aβ also triggers an inflammatory condition
through the nuclear factor kappa-light-chain-enhancer of
activated B cell (Nf-κB) signaling pathway, and activation
of microglial cells disrupts central nerves system (CNS)
homeostasis in the chronic state.73 The soluble form of Aβ
is attributed to production of imperative proteins related
to memory function (i.e. dendritic spines74). Soluble Aβ
was also shown to have a significant role in AD induction
and progression, and its levels rise in the brain,75 blood,
and the CSF76 of AD patients.77 Therefore, accumulation
or formation of Aβ plaque is an assessment factor for AD
diagnosis67,78 however, there is no known relation between
severity of disease and the insoluble form of Aβ or the
plaque numbers.78
Tau and Neurofibrillary Tangles in AD
Tau is a protein involved in assembling of tubulin into
microtubules79,80 able to interact with cytoskeletal proteins
actin and spectrin. In physiological conditions, neurons
are responsible for tau production; nonetheless, in certain
pathologic situations, it is also generated by glial cells.
Typically, tau proteins are expressed in the CNS; however,
the footprints of their mRNAs were also detected in other
tissues.81 It seems that tauopathy leads to neural death and
NFT formation, which was also correlated with neuronal
disturbance and severity of AD.82,83 Hyperphosphorylated
tau is the main reason behind its neurotoxic properties
and also participates in NFT production as a core
component.84,85
In addition, accumulation of tau is correlated with
various degenerative disorders such as AD, progressive
supranuclear palsy, argyrophilic grain disease, Pick’s disease,
Parkinson-dementia complex of Guam, and corticobasal
degeneration.86 Thus far, NFTs and Aβ are the most
important components of AD pathology. Indeed, AD-type
NFTs are mostly observed in the brain of old individuals
even when there are no Aβ plaques. People with NFTs in
the brain share comparable symptoms like AD. Regarding
resemblance of Primary age related tauopathy (PART) and
AD symptoms, by some definitions, PART is considered
as a pre-AD factor or a subtype of AD.87 Despite common
features of PART and AD, it has been demonstrated that
PART possesses limited effects on memory and cognition
compared to AD.88
Apolipoprotein E and AD
APOE is a gene encoding ApoE with 299 amino acids,
mainly existing in astrocytes. ApoE regulates lipid
homeostasis by modulating lipid transport between
different cells and by the action of ApoE receptors in the
brain.9 Liver and macrophages produce ApoE in peripheral
tissue and it plays an important role in cholesterol
metabolism. ApoE-4 is reported as a risk factor for various
disorders such as atherosclerosis, coronary artery disease,
peripheral artery disease, type 2 diabetes, and stroke; such
diseases are also correlated with AD onset.89-92
There are three major alleles of the APOE gene including
ε2, ε3, and ε410 displaying contradictory effects on AD
likely due to the difference in amino acid residues 112
and 158.91 People carrying ε4 are more prone to AD than
those carrying ε3, by far, especially the ε4 homozygotes. In
contrast, ε2 was shown to reduce AD risk.93-95 According
to various genome-wide studies, ε4 is the key genetic
risk factor for AD.96,97 Conversely, some studies refute
this statement because some people carrying the ε4 allele
never experience AD. However, they are susceptible to AD
twenty times more than others.98 It was shown that females
and ApoE-4 positive individuals can weakly regulate the
interaction between microglia cells and amyloid plaques,
leading to greater risk of AD.98 In addition, it was reported
that aging and ε4 allele synergistically increase the risk of
AD.8,99
The findings of human and animal studies demonstrated
that ApoEs mediate APP and regulate Aβ aggregation and
clearance (ε4> ε3> ε2) via triggering a non-canonical
mitogen-activated protein kinase (MAPK) signaling
pathway.8,100-102 It was stated that absence of ApoE leads
to elimination of fibrillar Aβ deposition in the APOE gene
knockout mouse model.103 ApoE-4 carriers have more
senile plaques and experience CAA more frequently than
non-carriers,104-106 enhancing the risk of AD.107 It was
indicated that the presence of the ε4 allele exacerbated the
consequences of sedentary lifestyle and aerobic exercise on
cognition in individuals who carry ε4 in comparison with
those not carrying this allele.108-110 Smoking tobacco,111-113
mild to moderate alcohol consumption,114 and diets
rich in high saturated fats113 have also been shown to be
responsible for higher risk of AD in ε4 carriers.
Anti-oxidant Effect of Saffron
The antioxidant properties of Crocus sativus and its
constituents were associated with their activities against
the oxidative enzymes; glutathione (GSH), glutathione
peroxidase (GPx), superoxide dismutase (SOD),23
catalase (CAT),115 glutathione reductase (GR), and
glutathione-S-transferase (GST).116 Thus, saffron and its
bioactive compounds can modulate oxidative stress in
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Zandi et al
cellular organelles and molecules, providing an effective
mechanism against neurodegenerative disorders such as
AD. It was demonstrated that stressed animals have higher
amount of malondialdehyde (MDA), as well as higher
activities of GR, GPx, and SOD enzymes in the brain,
liver and kidneys, with lower total antioxidant capacity,
compared with non-stressed animals.117 In stressed
groups, the corticosterone level was raised, confirming
the point that glucocorticoids are involved in chronic-
stress-induced oxidative damages, neuronal damage, and
impairment of antioxidant defense.118,119 Chronically
elevated glucocorticoids caused neurogenesis blockade,
hippocampal volume loss, and atrophy of dendrites in
hippocampal CA3 pyramidal neurons.120,121 Clinically,
these changes lead to stress-mediated impairments in
spatial learning and memory. Treatment with Crocus
sativus extract and crocins improved such damages in the
stressed group compared with the control group through
enhancement of cellular antioxidant and detoxifying
pathways.122
It was shown that the antioxidant components of
saffron, such as crocins, crocetin, safranal, and flavonoids
have synergic anti-oxidative effects, as the saffron extract is
more efficient than each component alone.123 Therefore,
saffron and its bioactive compounds suppress oxidative
and neuronal damages, and can thus alleviate cognitive
deficits. Several studies demonstrated that streptozotocin
(STZ) induces brain glucose deprivation and oxidative
stress in animal models. Reduced cerebral glucose uptake
and energy metabolism results in severe and progressive
memory loss and poor learning ability due to deficiency
in hippocampal choline acetyltransferase content.12,124
Glucose hypo-metabolism and impaired insulin signaling
were implicated in early onset and persistent complications
in AD. The behavioral alterations of STZ-lesioned rats
were attributed to increased MDA, as well as reduced
GSH, total thiol, and GPx activity in the brain.125
Crocins were shown to improve cognitive performance,
restore GPx activity, reduce lipid peroxidation and MDA
pool, and replenish total thiol content in STZ-injected
mice.125 Striatum was chosen for injection due to the fact
that it is particularly susceptible to oxidative stress damage
due to increasing endogenous levels of antioxidants.
Cerebral hypoperfusion leads to excessive reactive oxygen
species (ROS) generation, which overwhelms the brain’s
antioxidant machinery, especially in the cortex and
hippocampus.126,127 Crocus sativus extract and crocins
improved chronic cerebral hypoperfusion-induced
cognitive impairments in mice by means of their anti-
oxidative properties. In mice with cerebral ischemia-
reperfusion injury, safranal treatment significantly
restored the hippocampal antioxidant capacity and total-
SH content.128 Moreover, safranal elevated MDA levels
in a dose-dependent style in the rat hippocampus in one
animal study which was performed on male NMRI rats
and transient global cerebral ischemia model was induced
using the four-vessel-occlusion method for 20 min.23 In
vitro experiments on neuronally differentiated PC12
cells demonstrated that stress stimuli (i.e. serum/glucose
deprivation, hypoxia), triggers cellular oxidative stress
events like decline in intercellular levels of GSH and SOD
activity.23,128 Crocin treatment in PC12 cells attenuated
lipid peroxidation and preserved neuron morphology.
These effects were correlated to restoration of the activity
and expression of SOD, GR, γ-glutamyl-cysteinyl synthase
(γ-GCS), and the GSH pool. As mentioned, acrolein
activated MAPK/ERK signaling pathway in rat cerebral
cortex, as verified by phosphorylation of upstream kinases
ERK1/2, c-JNK and p-38, resulting in reduced GSH and
an enhancement of MDA content, Aβ deposition, and tau
phosphorylation. Co-administration of crocin modulated
MAPK signaling pathways, limited MDA pool, reduced
Aβ level and tau phosphorylation, and therefore, prevented
neuron apoptosis (Figure 1).129,130
Inhibition of AChE Activity and Saffron
It was proven that there is a significant correlation between
cholinergic deficiency and cognitive impairments in AD
pathogenesis, depending on ACh level in the brain.131
Cholinergic pathways encompass the medial forebrain
cholinergic nuclei and distribute to the hippocampus,
amygdala, and neocortex. AChE hydrolyzes ACh to
choline and the acetyl group. AChE inhibitors (AChEIs)
prevent this breakdown in the brain.132 However, increased
ACh precursors such as choline and lecithin are not useful,
but AChEIs have been found to be significantly effective in
improving cognitive impairments. Tacrine, donepezil, and
rivastigmine are approved AChEI drugs for AD treatment,
133-135 while there are many natural products that can act
similarly.135 Crocins have been shown to inhibit AChE
by enhancing ACh levels in synapses and ameliorating
cognitive symptoms.128,136 In a 22-week, double-blind
controlled trial, participants with mild to moderate AD
randomly consumed either a 30 mg/d capsule of saffron
or 10 mg/day of donepezil. Data showed the AChE ratio
was comparable for both groups, demonstrating that
saffron displayed the same therapeutic effect on cognitive
function as donepezil. Besides, patients consuming saffron
experienced less vomiting, slightly more dry mouth, and
hypomania (Figure 1).5
Inhibition of Aβ Aggregation by Saffron
It was reported that trans-crocetin decreased Aβ42
aggregation in vitro and increased the level of a key
Aβ42 degrading enzyme: the Aβ42-degrading lysosomal
protease cathepsin B (CatB). These data indicate CatB
involvement in the degradation pathway of Aβ42 in AD.
Additionally, the compound modulated the intracellular
level of CatB, suggesting a potential mechanism by which
the degradation ability of Aβ42 could be retrieved. Studies
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Saffron and its Derivatives in Alzheimer’s Disease
also revealed that trans-crocetin has a positive effect on
Aβ42 clearance and verified its neuroprotective effects
on Aβ42-induced toxicity in hippocampal-derived cells,
resulting in reduced cellular apoptosis.7,137 However, it
has been shown that crocetin affects multiple signaling
pathways involved in neurodegenerative diseases such as
extracellular signal-regulated kinase 1/2 (ERK-1/2) and
caspases.129,137 In the rat cerebral cortex, crocin alleviated
tau phosphorylation by suppression of ERK and c-Jun
N-terminal kinases (JNK) in acrolein induced oxidative
stress and amyloid toxicity, showing that modulation
of MAPK expression may be a mechanism underlying
the crocin neuroprotective characteristic.138 Supporting
this notion, ERK was shown to mediate Aβ-induced
tau phosphorylation.139 In organotypic hippocampal
slice cultures, both crocin and crocetin attenuated LPS-
induced hippocampal cell death by decreasing nitric oxide
(NO) release from activated microglia, highlighting their
neuroprotection abilities. It was also demonstrated that
crocin inhibited the Aβ42 formation and aggregation in
vitro.140,141 In the in vitro neuronal membrane bioreactor
model, concomitant administration of crocin and Aβ‐
peptide repressed apoptosis and ROS production dose
dependently.142 In the in vivo model of AD, the compound
inhibited Aβ‐induced apoptosis through modulating the
Bax/Bcl‐2 ratio and cleaved caspase‐3.143 In the same
manner, crocin prevented neuronal cell death caused by
both internal and external apoptotic stimuli in tumor
necrosis factor (TNF)‐α treated pheochromocytoma
PC12 cells via suppression of Bcl‐Xs, LICE, and release
of cytochrome c from mitochondria.144 In another study,
pretreatment with safranal reduced Aβ42 induced cell
toxicity and apoptosis via MAPK and phosphoinositide
3-kinases (PI3K) pathways in PC12 cells.137 In an Aβ-
induced rat model, application of safranal (0.025, 0.1,
and 0.2 mL/kg) for a week improved cognition deficits,
and reduced CA1 neuronal loss and the hippocampal
levels of MDA, ROS, protein carbonyl, interleukin 1β
(IL-1β), IL-6, TNF-α, Nf-κB, apoptotic biomarkers
and DNA fragmentation, glial fibrillary acidic protein
(GFAP), myeloperoxidase (MPO), and AChE activity,
while enhancing the SOD activity and mitochondrial
membrane potential (Figure 1).145
Inhibition of Aβ-Induced Inflammation by Saffron
High concentrations of neuroinflammatory cytokines
were observed in AD brains. Aggregation of Aβ plaques in
the brain leads to enhanced neuroinflammatory cytokine
levels such as IL-1β, IL-18, interferon-γ (IFN-γ), and
TNF-α. This enhancement has been correlated with
overproduction of APP in glial cells and upregulation
of β- and γ- secretaseenzymes, which split APP and
produce Aβ.146,147 Animal studies pointed out that crocetin
treatment lowered inflammation, prevented Aβ toxicity
and reduced Aβ accumulation by enhancing tightness of
the blood brain barrier (BBB), attenuating the increase of
NF-κB p65 subunit and P53 in AD mice hippocampus.
As a result, nitric oxide synthase (iNOS) production
increased whereas proinflammatory cytokines such as IL-
1β, IL-18, IFN-γ, and TNF-α diminished (Figure 1). 148
Inhibition of tau Phosphorylation by Saffron
It was shown that corcin inhibited the beta-structure/
random coil ratio of tau protein under fibril state and the
aggregation of 1N/4R human tau protein in PC12 cells,
which was correlated with its chemical structure. It was
Figure 1. Inhibitory Effect of Saffron and/or its Derivatives in AD. Amyloid precursor protein (APP) is the main source of amyloid β plaques in the brain. Crocetin
lowered the APP level by decreasing the inflammatory cytokines (IL1β, IL18, INFγ, and TNFα). Also, safranal and crocin inhibited the ROS formation resulted
from increased stress. Crocin has been shown to inhibit acetylcholine esterase (AChE) and enhances the acetylcholine (ACh) in the neuronal synapses which
ameliorates the cognitive symptoms.
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Zandi et al
proposed that carbonyl groups of crocin could interact
with lysine residues of tau, leading to disruption of fibril
formation.149 As mentioned, in the rat cerebral cortex,
crocin suppressed acrolein induced tau phosphorylation
through modulation of ERK and JNK pathways.138
Organophosphorus pesticides are accounted as important
risk factors of AD. Mohammadzadeh et al reported that
crocin (10, 20 and 40 mg/kg) improved spatial memory
deficits in rats through inhibition of postsynaptic
density protein 93 (PSD93) gene expression and tau
phosphorylation. Besides, crocin significantly alleviated
both oxidative and inflammatory parameters such as
MDA, TNF‐α and IL-6 levels, while increasing GSH in
the hippocampus. The compound also reduced the plasma
AChE activity and malathion-induced apoptosis in the
hippocampus cells.150
Saffron and ApoE Related Approaches
Transcriptions of ApoE and ABCA1 are regulated via the
linkage of peroxisome proliferator activated receptor γ
(PPARγ) and liver X receptor (LXRs) to the retinoid X
receptor (RXR).151 It was shown that deletion of ABCA1
led to an increase in Aβ deposition in the murine brain,
especially in ApoE-4 carriers, signifying its function in
Aβ clearance.152 ABCA1 regulates the ApoE lipidation by
means of cholesterol efflux to ApoE and adjusts the ApoE
level. On the other hand, binding of ApoE to Aβ changes
the conformation of Aβ and increases its clearance.153 In the
Batarseh study, administration of saffron extract enhanced
ABCA1 and PPARγ expression in murine brain, which
led to Aβ degradation and deposition by modulating the
BBB clearance and upregulation of ApoE-dependent Aβ
clearance pathway (Figure 1).148
Clinical Trials on Saffron and AD
The mechanism of action of saffron in AD treatment and
clinical trials is still under investigation. As previously
mentioned, saffron showed similar efficacy as donepezil
on patients with mild to moderate AD after 22 weeks by
exploiting clinical assessment methods; the Alzheimer’s
Disease Assessment Scale-cognitive subscale (ADAS-cog)
and Clinical Dementia Rating Scale-Sums of Boxes (CDR-
SB).154 Memantine is another approved drug for AD
treatment, known to block the glutamatergic N-Methyl-
D-aspartic acid (NMDA) receptors and their mediated
excitotoxicity in the brain. Administration of saffron at
low dose (30 mg/kg) resulted in the same outcomes as
Memantine in moderate to severe AD patients. The Severe
Cognitive Impairment Rating Scale (SCIRS) scores for both
groups indicated no significant difference in the baseline
and the final outcomes of the therapy.155 Furthermore, the
results of 16 weeks of saffron therapy versus placebo in
individuals with mild to moderate AD were in line with the
aforementioned clinical trials. Indeed, saffron significantly
prevented cognitive impairments compared to placebo,
highlighting the hypothesis that saffron is beneficial to
people suffering from AD and memory deterioration.156
Administration of saffron with standardized herbal
medicine formula named sailuotong, containing Panax
ginseng and Gingko biloba, showed potential effectiveness
in improving working memory in comparison with
placebo in healthy adults.157 Concomitantly, application of
saffron at a dose of 125 mg/d for a year enhanced cognitive
function compared with the control group, suggesting
that saffron may be an alternative medicine for AD
drugs.158 In a single blind randomized trial, 17 patients
diagnosed with amnesic and multi domain mild cognitive
impairment (aMCImd) were treated with saffron over a
year. Neuropsychological assessment included a battery
of psychometric tests assessing mood, activities of daily
life, behavior, magnetic resonance imaging (MRI) 3T,
and general cognitive function, while some patients were
assessed via 256-channel electroencephalogram (HD-
EEG). The findings of the study showed that saffron
improved the MMSE scores, while amending the MRI,
EEG, and event-related potential (ERP) in latency of
P300 domain, suggesting that saffron may be a choice for
MCI therapy (Table 1).158
In Vivo Interventions of Saffron and AD
Regarding the potential role of oxidative stress in
pathogenesis of AD and other neurodegenerative diseases,
the efficacy of saffron extract was investigated in BALB/c
mice hippocampus cells with neuronal damage induced
by D-galactose and sodium nitrite (NaNO2). While
D-galactose increased free radicals and NaNO2 caused
hypoxia, saffron inhibited the neurotoxicity resulting from
their actions. This investigation suggested that in addition
to anti-oxidative actions, saffron can also increase cerebral
blood flow.159 Administration of crocin in ddY mice after
brain infarction induced by occlusion of a middle cerebral
artery led to significant reduction of the infarcted area via
passing the BBB. Interestingly, crocin was effective in a
dose ten-fold less than α-tocopherol.160 Similarly, 8 mg/
kg crocetin reversed memory derangement in the vascular
dementia model in rats including cortical and hippocampal
hypoperfusion through permanent occlusion of common
carotids, which has been confirmed in histopathological
analysis.161 In accordance, Hosseinzadeh et al162 found that
crocin (25 mg/kg) and saffron (250 mg/kg) attenuated
memory deficits via decreasing oxidative stress in Wistar
rats.
Zheng et al reported that following cerebral ischemia
in C57BL/6J mice, pre-treatment with crocin and saffron
inhibited oxidative stress parameters such as MDA and
NO, while it enhanced the GPx, SOD, and iNOS activities.
In addition, other oxidative markers, phosphorylation
of ERK1/2, and the expression of membrane G protein-
coupled receptor kinase 2 (GRK2) was reduced. The
structure of cortical microvascular endothelial cells was
Arch Iran Med, Volume 24, Issue 3, March 2021 239
Saffron and its Derivatives in Alzheimer’s Disease
preserved by crocin.163
In a similar manner, pre-treatment with crocin and
saffron in rats modulated the CAT and Na-K ATPase
activities as well as aspartate and glutamate levels.40
Increased lipid peroxidation is known as a marker of
oxidative stress and IP exposure of saffron extract in Wistar
rats led to lipid peroxidation reduction and amelioration of
mitochondrial function in synaptosomal fractions, which
were predisposed to the neurotoxin mitochondrial toxin
3-nitropropionic (3-NPA).126 IP and intrahippocampal
administration of crocin significantly improved the
indicators of spatial memory. In Wistar rats, application
of crocin reduced the Bax/Bcl-2 ratio and apoptosis, while
the ratio of autophagy markers Beclin-1 and LC3-II/
LC3-I remained unchanged.143
Moreover, administration of crocin improved sporadic
AD induced by STZ in Wistar rats. According to the result
of the Passive Avoidance Test and Maze Task Performance,
memory and learning deficits were attenuated in the crocin
group.164-166 From a molecular viewpoint, crocin decreased
MDA levels while elevating the total thiol level and the GPx
activity in contrast to STZ.165 Likewise, pretreatment with
NCSe (combination of Nardostachys jatamansi, crocetin
and selenium) in Wistar rats attenuated STZ-elicited
oxidative stress by reducing thiobarbituric acid reactive
substance level and increasing the glutathione, GPx, GST,
and CAT activities, resulting in better performance in
passive avoidance test and Morris water maze. Notably,
this study mentioned that a multi-substance approach
can be more potent than singular therapy.167 Pretreatment
of Wistar rats with saffron extract or crocin for 21 days
before predisposition to chronic stress showed a significant
neuroprotective effect on the hippocampus and an
escalation in anti-oxidative stress markers,168,169 as well as
the mRNA expressions of CAT and SOD.170 In another
study, pre-treatment with a low dose of saffron prevented
learning deficits induced by scopolamine in Wistar rats
whereas post-treatment with saffron extract significantly
retrieved data storage and recognition memory.171,172 These
data are against with findings by Zhang et al.173
It has been reported that saffron extract modified
morphine-induced memory deficits in mice,47 which is in
line with the study by Haghighizad et al which indicated
the efficacy of saffron extract on improving morphine-
induced spatial learning and memory deficit in rats. Other
investigations achieved the same results in ethanol-induced
memory deficits in Std-ddY mice.174
Moreover, administration of 15-30 mg/kg crocin in
Wistar rats reduced ketamine (non-competitive NMDA
receptor antagonist) induced memory impairments
using the novel object recognition task.48 Saffron extract
attenuated the acetaldehyde-induced inhibition of
Table 1. Saffron and its Derivatives; Clinical Interventions in AD (Human Study)
Study Design Study
Assessment
Intervention Number of Patients Treatment
Duration Outcomes Adverse Effects Ref.
Case Control Case Control
Mild to
moderate AD
MMSEADAS-
cog, CDR-SB
SE (15 mg twice/
day), oral
donepezil
(5 mg
twice/
day)
n = 24 n = 23 22 weeks Effective as donepezil
Dizziness, dry mouth,
fatigue, hypomania,
nausea (adverse effects
were similar in both
treatment & control
groups, except vomiting)
154
Mild
cognitive
impairment
MMSE SE (125 mg/d),
oral - n = 17 n = 18 12 months Improvement of
cognitive dysfunction -158
Healthy
adults
Cognitive test
scores, oddball
task -ERP
Sailuotong (Panax
ginseng, Ginkgo
biloba & Crocus
sativus)
(120 mg/d)
Placebo n = 8 n = 8 1 week
Increase of Sailuotong
in alphabetic working
memory & visual
working memory
-157
Mild to
moderate AD
MMSEADAS-
cog, CDR-SB
SE
(15 mg twice/day) Placebo n = 22 n = 20 16 weeks Improvement of
cognitive function
Dizziness, dry mouth,
fatigue, hypomania,
nausea (adverse effects
were similar in both
treatment & control
groups)
156
Moderate to
severe AD MMSE SE (30 mg/d) Memantin
(20 mg/d) n = 30 n = 30 12 months
Effective as Memantin
in reducing cognitive
decline
Nausea, vomiting, dry
mouth, fatigue, dizziness,
confusion, agitation,
sedation (adverse effects
were similar in both
treatment & control
groups)
155
SE, saffron extract; MMSE, Mini-mental state examination; ADAS-cog, Alzheimer’s disease assessment scale-cognitive subscale; CDR-SB, Clinical dementia
rating scale-sums of boxes; ERP, event-related potential; MRI, magnetic resonance imaging.
Arch Iran Med, Volume 24, Issue 3, March 2021
240
Zandi et al
hippocampal long-term potentiation in Wistar rats.175
For in vivo studies, one of the best proficient models
of AD can be imitated by chronic administration of
aluminum due to the same neurotoxic pathological changes
in the brain.176-179 Al accumulation in the brain leads
to oxidative stress in the hippocampus and the cerebral
cortex including lipid peroxidation, and deterioration of
endogenous antioxidant enzymes, protein kinases, and
Na+-K + ATPase in the cell membrane.180-182 It was shown
that short-term co-administration of saffron extract with Al
alleviated the oxidative stress markers and the monoamine
oxidase activity; however, there was no effect on cognitive
function and memory capacity in BALB/c mice.41 Oral
administration of 100 mg/kg saffron extract reversed the
arsenic neurotoxicity while it promoted cognitive and
memory functions. This was accompanied by decreasing
glutamate and aspartate levels in cortical and hippocampal
areas in Wistar rats.46
Various parts of the human body are affected by aging
which ultimately results in dementia and progressive brain
dysfunction. Oxidative stress in lipids, proteins and nucleic
acids183-185 along with poor performance of the cholinergic
system due to reduced AChE activity in different parts of
the cerebrum49 and synaptic plasma membranes186 is the
basis for the main hypothesis for memory impairment in
aged humans and rodents. In the study by Papandrou et al,
crocetin decreased lipid peroxidation and caspase 3 activity
in both adult and aged mice although the AChE activity
was reduced in only adult BALB/c mice, emphasizing the
greater role of oxidative stress in cognitive dysfunction
compared to the cholinergic system (Table 2).136
In Vitro Interventions of Saffron and AD
In vitro administration of safranal, crocetin, and
dimethylcrocetin inhibited ds and preserved the SOD
activity which were exposed to serum/glucose deprivation.
Moreover, crocin suppressed the caspase-8 (an initiator
caspase) activity and increased the survival time of
neuronal cells. It was indicated that the anti-oxidative
ability of crocin was more than α-tocopherol (a form of
vitamin E) at the same dosage.188 Comparison of different
saffron carotenoids revealed that 10 μM crocin is more
potent than tricrocin and dicrocin in terms of reducing
the GSH and caspase 3 activities in PC12 cells.160
Saffron and crocetin showed neuroprotective effects
on H2O2 induced toxicity in human neuroblastoma SH-
SY5Y cells by diminishing ROS products and caspase 3
activity.136 Pretreatment of PC12 with 10-50 μg crocin in
the neurotoxic state, induced by acrylamide, reinforced
the neuroprotective effect of this compound. Indeed,
crocin suppressed intracellular ROS production and
apoptosis in these cells.189 The same neuroprotective
action of crocin was recorded in PC12 cells toxicated
by either glucose or high levels of ROS.190 In crocin
pre-treated neurotoxic PC12 cells, the ratio of Bax/Bcl-
2 decreased due to the apoptosis inhibitory effect of
this compound.189,191,192 Crocin downregulated TNF-α
receptor activity in PC12 cells (mainly through the
suppression of Bcl-2 mRNA expression) and increased
caspase 3 activity. Besides, crocin prevented intracellular
ROS formation elicited by daunorubicin.144 In another
study, 10 μM of crocin significantly restored ethanol
induced NMDA receptor dysfunction and improved
memory impairment in hippocampal slices of male Wistar
rats.45 Crocin suppressed 1-methyl-4- phenylpyridinium-
induced endoplasmic reticulum stress and mitochondrial
dysfunction in PC12 cells.193 It is well established that
microglial cells play pivotal roles in CNS homeostasis,
but chronic activation of microglial cells predisposes
neuronal cells to the inflammatory state by producing
inflammatory cytokines including IL6, IL1β, TNF-α, and
Nf-κB transcriptional activity as well as NO release. It
was shown that saffron extract repressed the expressions
of these elements in BV2 mouse brain microglial cells.194
Overall, the neuroprotective features of crocin are mainly
attributed to reduction of pro-inflammatory cytokines and
neurotoxic factors (Table 3).187,194
Safety
Animal Studies
Considering the worldwide application of saffron,
monitoring the probable adverse effects of this plant and
its bioactive components seems necessary. Acute oral
application of saffron in mice and rats was shown to be safe.
Following IP administration in mice, the 50% lethal dose
(LD50) for saffron was reported as 1.6 g/kg, while for oral
intake, LD50 was 4120 ± 556 mg/kg.195 Administration of
3 g/kg crocin (IP and PO) for two days did not cause any
mortality in mice; therefore, it was deduced that crocin
is the safest substance of saffron.196 Safranal exhibited
LD50 values of 0.75 mL/kg and 3.5 mL/kg for IP and
oral administration in male Wistar rats, respectively.196
In rats, sub-acute IP exposure to saffron ethanolic extract
decreased body weight, red blood cell (RBC) count,
hemoglobin (Hb), and hematocrit (Hct). Conversely in a
dose-dependent manner, white blood cells (WBC), alanine
aminotransferase (ALT), aspartate aminotransferase (AST)
enzymes, serum urea, uric acid, and creatinine (Cr) levels
increased. Pathological findings represented some mild to
moderate liver and renal damage.197
Evaluation of saffron regarding spermatogenesis index
in rats showed oral administration of 200 mg/kg saffron
for 28 days reduced tubular differentiation index,
spermatogenesis index, and repopulation index.198 Another
in vivo study demonstrated that crocin (90 mg/kg) for 21
days increased the low-density lipoprotein (LDL) level,
while decreasing alkaline phosphatase (ALP) and albumin
levels, without serious injuries in main organs even after
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Saffron and its Derivatives in Alzheimer’s Disease
Table 2. Saffron and its derivatives; in vivo interventions in AD (Animal Study)
Animal Type Disease Model
(AD)
Intervention Number of Animals Treatment
Duration Outcomes Adverse Effects Ref.
Case Control Case Control
BALB/c mice D-galactose (90 & 120 mg/
kg), i.p SE (30 mg/kg/d), i.p Water, i.p
1. amnestic treatment
(n = 10)
2. amnestic prophylaxis
(n = 10)
1. amnestic control
(n = 10)
2. normal control (n = 10)
15 days
Improvement of learning memory
impairment in amnestic induced
groups
-159
Wistar rats 3-NPA (20 mg/kg/d), i.p SE (1 mg/kg/d),
i.p Saline, i.p n = 6 n = 6 5 days SE improves mitochondrial function
via reduction in LP 126
Wistar rats STZ, i.c.v Crocin (15 & 30 mg/
kg/d), i.p. Vehicle n = 15 n = 15
One day pre-
surgery &
continued for 3
weeks
↓ Memory deficits at higher dose ↑ Weight
loss (crocin>
crocin+STZ)
164
BALB/c mice Aluminum chloride (50
mg/kg/d), oral SE (60 mg/kg/d), i.p Water, oral n = 10 n = 10 5 weeks No changes in cognitive function; ↓
MAO & AChE activity, ↓ LP & GSH 41
BALB/c mice - SE (60 mg/kg/d)
i.p Saline, i.p Aged n = 8
Adult n = 8
Aged n = 8
Adult n = 8 7 days
Improvement of learning & memory
impairment, ↓ LP, ↑ total brain
antioxidant activity, ↓ caspase-3
activity in both aged and adult groups
- 136
Mice Morphin (5 mg/kg), s.c SE (50,150,450 mg/
kg), i.p
Saline, i.p n = 8 n = 8 3 days Improvement of memory impairment - 47
Wistar rats Arsenic (100 mg/kg), oral SE (100 mg/kg),
gavage needle -n = 6 n = 6 - Improvement of learning ability,
↓Glutamate & aspartate levels -46
Wistar rats Amyloid β (100 ng/μL),
i.p & i.h
Crocin (150, 300, 600
nm), i.p & i.h - - - - Crocin ↑
Spatial memory, ↓ brain death 143
Wistar rats Ketamine (3-25 mg/kg), i.p Crocin (15, 30 & 50 mg/
kg), i.p Vehicle n = 8 n = 8 3 days Revision of memory deficits at 50 mg/
kg -48
Wistar rats STZ (3 mg/kg on day 1 &
3), i.c.v Crocin (100 mg/kg), oral Vehicle - - 21 days
Improvement of cognitive function,
↓ MDA, ↑ total thiol content & GPx
activity
165
Wistar rats STZ
Combination of
Nardosatchys jatamansi
extract (200 mg/kg),
crocetin (25 mg/kg)
& selenium (0.05 mg/
kg), oral
Saline, oral - - 15 days ↓ Cognitive dysfunction 167
Arch Iran Med, Volume 24, Issue 3, March 2021
242
Zandi et al
Animal Type Disease Model
(AD)
Intervention Number of Animals Treatment
Duration Outcomes Adverse Effects Ref.
Case Control Case Control
Wistar rats Ethidium bromide (3 μL),
i.h SE (5−10 μg), i.h Saline n = 8 n = 8 1 week
Improvement of spatial learning &
memory improvement, restoration of
antioxidant status to the normal levels
in hippocampus
-212
Rats Chronic cerebral
hypoperfusion crocetin (8 mg/kg), i.p Control - - -
Prevention of neuropathological
alterations in hippocampus,
improvement of spatial learning
memory
-161
Wistar rats BeCl2 (86 mg/kg), oral crocin
(200 mg/kg), i.p -n = 8 n = 8 7 days ↓ Oxidative stress, ↑mRNA expression
of SOD & catalase -170
Wistar rats Scopolamine (0.2 mg/
kg), i.p
crocins (15 and 30 mg/
kg), i.p -n = 10 n = 10 2 days
Crocins (15 mg/kg)
↓ Memory impairment & ↑ recognition
memory
171
Wistar rats scopolamine (0.2 mg/
kg), i.p SE (250 mg/kg), oral - - - - ↓Hippocampal LTP - 175
Std-ddY mice Ethanol (10 ml/kg), po Crocin (50 to 200 mg/
kg), p.o - - - 2 days ↓ Learning behavior impairments &
memory retrieval deficits 174
C57BL/6J
mice
Carotid occlusion-
reperfusion Crocin (5,10,20 mg/kg) - n = 10 n = 10 21 days
Neuroprotective effect, ↓ GRK2
translocation from the cytosol to the
membrane, ↓ ERK1/2 phosphorylation,
↓ expression of MMP-9 in cortical
microvessels
-163
Std-ddY mice
Scopolamin (0.5 mg/kg),
i.p & ethanol (10 mg/kg),
oral
SE, oral - - - Single dose ↓ Memory impairment - 173
Table 2. Continued
Arch Iran Med, Volume 24, Issue 3, March 2021 243
Saffron and its Derivatives in Alzheimer’s Disease
Animal Type Disease Model
(AD)
Intervention Number of Animals Treatment
Duration Outcomes Adverse Effects Ref.
Case Control Case Control
Wistar rats (60 mg/kg), STZ i.p Crocin (7.5, 15, 30, 60
mg/kg), i.p Saline, i.p n = 6 n = 6 30 days Improvement of learning & memory
impairments 166
Wistar rats Scopolamin (0.75 mg/
kg), s.c SE (10,30,60 mg/kg), i.p Vehicle, i.p/s.c n = 10 n = 10 -↓ Memory impairment - 172
Wistar rats Chronic stress
SE (30 mg/kg)
Crocin (15, 30 mg/
kg, s.c
Vehicle
s.c n = 10 n = 10 21 days Prevention of learning impairments &
memory deficits; ↓ oxidative stress -169
Wistar rats Cerebral ischemia
SE (50, 100, 250 mg/
kg), i.p
Crocin (5, 10, 25 mg/
kg), i.p
Saline n = 7 n = 14 - Improvement of spatial cognitive
abilities -162
Wistar rats Chronic stress SE or crocin (30 mg/
kg), i.p Saline, i.p n = 6 n = 6er group 21 days Prevention of brain oxidative damage,
↓ LP & MDA, ↑ GPx, SOD, GR -168
ddY mice Middle cerebral artery
obstruction
crocin
(10 mg/kg), i.v. - - - 1 day ↓ Infarcted area via passing BBB - 160
Wistar rats Amyloid β (5 μg/μL), Safranal (0.025, 0.1, 0.2
ml/kg/day), p.o -n = 11 n = 11 1 week
↓ CA1 neuronal loss, the hippocampal
MDA, ROS, protein carbonyl,
interleukin 1β (IL-1β), IL-6, TNF-α,
Nf-κB, apoptotic biomarkers & DNA
fragmentation, glial fibrillary acidic
protein (GFAP), myeloperoxidase
(MPO), AChE activity, ↑ SOD &
mitochondrial membrane potential
-145
Wistar rats Malathion (100 mg/kg/d),
i.p
Crocin
(10, 20, 40 mg/kg), i.v Saline, i.p n = 6 n = 6 14 days
↓ PSD93, tau phosphorylation, MDA,
TNF-α, IL-6, plasma AChE activity
& malathion-induced apoptosis in
hippocampus cells, ↑ GSH
-150
LPO, Lipid peroxidation; GSH, Gluthatione; AChE, Acetylcholine esterase; GPx, Gluthatione peroxidase; SOD, Superoxide dismutase; IL, Interleukin; MDA, Malondialdehyde; PSD93, Postsynaptic density protein 93; GFAP, Glial fibrillary
acidic protein; TNF-α, Tumor necrosis factor; Nf-κB, Nuclear factor kappa-light-chain-enhancer of activated B cell (Nf-κB); BCR, Beryllium chloride; LTP, Long-term potentiation; GR, Gluthatione reductase; BBB, Blood brain barrier; GRK2,
G protein-coupled receptor kinase 2; ERK1/2, Extracellular signal-regulated kinase1/2; i.p, Intraperitoneal; i.c.v, Intracerebroventricular; s.c, Subcutaneous; i.h, Intrahippocampal; p.o, per os
↓: decrease, ↑: increase
Table 2. Continued
Arch Iran Med, Volume 24, Issue 3, March 2021
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Zandi et al
Table 3. Saffron and its Derivatives; In Vitro Interventions in AD
Ref. Cell Type Study Model of AD Intervention Number of Cells Treatment
Duration Results
Case Control Case Control
187 - Kinetic analysis of AChE Crocin, crocetin,
dimethylcrocetin, safranal
Control &
galanthamine - - - AChE inhibition activity;
Safranal> crocetin > dimethylcrocetin
49 -Ferric-reducing antioxidant power &
Trolox-equivalent antioxidant capacity
SE (50:50 water & methanol) - - - - ↑ Cognitive function via antioxidant & antiamyloidogenic
activity, ↑ cognitive function
45 Hippocampal slices
of male Wistar rats Ethanol Crocin (10 μM) - - - - Revision of the inhibitory effect of ethanol on NMDA receptor-
mediated responses
193 PC12 1-methyl-4-phenylpyridinium (MPP+) Crocin - - - - ↓ MPP+-induced ER stress & cell injury
189 PC12 acrylamide
(5 mM) Crocin (10–50 mM) - - - - ↓ Apoptosis,
↓ Intracellular ROS formation
194
BV2 mouse
microglial cells;
hippocampal slice
cultures organotypic
of rats
LPS Crocin, crocetin - - - - ↓ Cell death, ↑ anti-oxidative & anti-inflammatory effects
160 PC12 Serum-free & hypoxic induced cell-
death Crocin (10 μM) - - - - ↓ infarcted areas
188 PC12 Serum/glucose deprivation Crocin (10 mM ) - - - - ↓ LP content, ↑ SOD activity, protected neuron’s morphology
136 Neuroblastoma SH-
SYS5 human cells H2O2 SE & crocetin (1-125 μmol) - - - - ↓Cell death, ↓ caspase 3 activity & ROS formation
144 PC12 TNF-α & daunorubicin Crocin (1−10 μM) - - - - ↓ Cell death, ↓ both internal
& external apoptotic stimuli
190 PC12 High glucose (4.5, 13.5, & 27 mg/mL) SE (5 & 25 μg/mL), crocin
(10, 50 μM) - - - 4 days ↓ Cell death, ↓ ROS production
& glucose toxicity
141 -Na2HPO4
NaCl (100 mM) Crocin (15.4 µM) - - - - ↓ Amyloid fibril content of Aβ; inhibits Aβ aggregation
140 -Na2HPO4
NaCl (100 mM) Crocin (15 µg/mL) - - - - ↓ Aβ40 average fibril length, ↓ formation of Aβ fibril formation
213 PC12 - Crocin (10 µg/mL) - - - - ↓ Tau protein fibrillation
SE, Saffron extract; MPP+, 1-methyl-4-phenylpyridinium; LPS, Lipopolysaccharide; LP, Lipid peroxidation; SOD, Superoxide dismutase; ROS, Reactive oxygen species
↓: decrease, ↑: increase
Arch Iran Med, Volume 24, Issue 3, March 2021 245
Saffron and its Derivatives in Alzheimer’s Disease
exposure to 180 mg/kg of crocin.196 This was in line with
results of a study by Taheri et al since IP administration of
crocin at concentrations of 50, 100 and 200 mg/kg once
a week for four weeks caused no elevation in Cr, ALT,
AST, ALP, uric acid and urea levels in rats. Pathological
examination revealed no significant hepatic toxicity.199
Three weeks of safranal oral administration (0.1, 0.25, 0.5
mL/kg) in rats, led to reduction of triglyceride, cholesterol,
ALP, RBC count, platelet count, Hb, and Hct, while the
level of blood urea nitrogen (BUN) increased. However,
no pathological lesion in organs (liver, spleen and heart) or
toxicity effect on the cellular and humoral immune system
were detected.200 Oral administration of 4000 and 5000
mg/kg saffron in BALB/c mice for 5 weeks demonstrated
that sub-chronic exposure to saffron decreased the RBC
and WBC counts and increased BUN and Cr, indicating
renal dysfunction.201 Worth mentioning, usually in animal
studies, saffron is used at high doses although it exhibited
protective effects in lower doses.202
Human Studies
Like other plant extracts, several side effects were reported
for saffron such as nausea, vomiting, anxiety, headache,
dizziness, epistaxis, bloody diarrhea, and numbness. It was
assumed that at doses of 12-20 g, saffron can be fatal.203
In a clinical study on healthy volunteers, standing
systolic blood pressure and mean arterial pressure were
reduced by receiving saffron tablets (400 mg); however,
there was no change at a dose of 200 mg.204 In another
study, hematologic factors and the coagulation system
were not disturbed by saffron tablets (200 and 400
mg).205 Safety of crocin was investigated in a double-
blind, placebo-controlled trial in which healthy volunteers
received crocin tablets (20 mg) for a month. Crocin tablets
decreased amylase, partial thromboplastin time, and the
WBC count, demonstrating that crocin was relatively
safe.206 Pregnant women with fetuses at gestational ages
between the first and twentieth weeks were susceptible
to abortion if they received saffron at high doses.207 In
addition, uterine contractions induced by saffron have
been suggested as a mechanism for abortion.204,208,209 At
the beginning of the active phase of labor, administration
of saffron capsules (250 mg) reduced mean anxiety score
and mean fatigue score,210 while saffron capsules in the
active phase of labor reduced pain. The infant and mother
did not show any toxicity in the saffron group compared
with controls.211
Based on the findings of animal studies (LD50 values),
crocin might be the safest component of saffron, and no
significant damage has been mentioned for this compound
at pharmacological dosage. At high concentrations, saffron
and its constituents showed some developmental toxicity
on animal infants. Exposure to high levels of saffron was
shown to increase miscarriage rates in pregnant women,
suggesting avoidance of high doses during pregnancy.202
Conclusion and Future Perspectives
Statistics confirm that AD remains a global growing health
concern. A wide range of natural and synthetic molecules
have been studied for their ability to either prevent or
counteract AD initiation, progression, and complications.
The findings of this study indicate that saffron and/
or its components target various regulatory molecules
involved in AD. Regarding its pleotropic effects on the
nervous system, including anti-amyloid, anti-AChE,
anti-inflammatory, and anti-oxidant features, along with
its inhibitory effect on tau hyper-phosphorylation, and
upregulation of ApoE activity, it seems that saffron could
find its niche in AD therapy with substantial potential
as a therapeutic nutraceutical with the advantage of low
toxicity and easy accessibility. Further studies, particularly
clinical trials, are now required to determine whether
saffron and its bioactive phytochemicals may be suitable for
AD or other neurodegenerative disorders. Other clinical
trials are warranted to examine the safety and efficacy of
various doses of the plant and improved formulations with
better pharmacokinetics and bioavailability are needed.
Several reports have raised questions about the safety
and efficacy of saffron or its derivatives, especially at high
doses, whereas some studies have shown no adverse effects.
It is suggested that the mode of administration and the
duration of saffron therapy are also critical factors that
can significantly affect the efficacy of AD treatment. Since
saffron is a part of daily diets in many Asian countries and
seems non-toxic, it is obligatory to investigate whether
dietary supplementation with saffron may be a beneficial
preventive or slowing nutritional strategy for neurological
disorders.212
Authors’ Contribution
NZ, BP, NMR and NAL: collection and/or assembly of data and
interpretation, manuscript writing; SM, VJ, AHA and SA: provision
of study material, conception and design, and final approval of
manuscript. All the authors have read and approved the manuscript.
Conflict of Interest Disclosures
None.
Ethical Statement
Not applicable.
References
1. Bhardwaj D, Mitra C, Narasimhulu CA, Riad A, Doomra M,
Parthasarathy S. Alzheimer’s Disease—Current Status and
Future Directions. J Med Food. 2017;20(12):1141-51. doi:
10.1089/jmf.2017.0093.
2. Brookmeyer R, Johnson E, Ziegler-Graham K, Arrighi HM.
Forecasting the global burden of Alzheimer’s disease.
Alzheimers Dement. 2007;3(3):186-91. doi: 10.1016/j.
jalz.2007.04.381.
3. Tsuno N. Donepezil in the treatment of patients with
Alzheimer’s disease. Expert Rev Neurother. 2009;9(5):591-8.
doi: 10.1586/ern.09.23.
4. Mohamed T, Shakeri A, Rao PP. Amyloid cascade in
Alzheimer’s disease: recent advances in medicinal chemistry.
Eur J Med Chem. 2016;113:258-72. doi: 10.1016/j.
ejmech.2016.02.049.
Arch Iran Med, Volume 24, Issue 3, March 2021
246
Zandi et al
5. Adalier N, Parker H. Vitamin E, turmeric and saffron in
treatment of Alzheimer’s disease. Antioxidants (Basel).
2016;5(4):40. doi: 10.3390/antiox5040040.
6. Swerdlow RH, Burns JM, Khan SM. The Alzheimer’s disease
mitochondrial cascade hypothesis: progress and perspectives.
Biochim Biophys Acta. 2014;1842(8):1219-31. doi: 10.1016/j.
bbadis.2013.09.010.
7. Barage SH, Sonawane KD. Amyloid cascade hypothesis:
Pathogenesis and therapeutic strategies in Alzheimer’s
disease. Neuropeptides. 2015;52:1-18. doi: 10.1016/j.
npep.2015.06.008.
8. Reiman EM, Chen K, Liu X, Bandy D, Yu M, Lee W, et al. Fibrillar
amyloid-β burden in cognitively normal people at 3 levels of
genetic risk for Alzheimer’s disease. Proc Natl Acad Sci U S A.
2009;106(16):6820-5. doi: 10.1073/pnas.0900345106.
9. Mahley RW, Weisgraber KH, Huang Y. Apolipoprotein E4:
a causative factor and therapeutic target in neuropathology,
including Alzheimer’s disease. Proc Natl Acad Sci U S A.
2006;103(15):5644-51. doi: 10.1073/pnas.0600549103.
10. Nussbaum RL, McInnes RR, Willard HF. Thompson &
Thompson genetics in medicine e-book. Elsevier Health
Sciences; 2015.
11. Bird TD. Alzheimer disease overview. GeneReviews®[Internet]:
University of Washington, Seattle; 2018.
12. Naghizadeh B, Mansouri MT, Ghorbanzadeh B. Protective
effects of crocin against streptozotocin-induced oxidative
damage in rat striatum. Acta Med Iran. 2014;52(2):101-5.
13. Karch CM, Cruchaga C, Goate AM. Alzheimer’s disease
genetics: from the bench to the clinic. Neuron. 2014;83(1):11-
26. doi: 10.1016/j.neuron.2014.05.041.
14. Heneka MT, Carson MJ, El Khoury J, Landreth GE, Brosseron F,
Feinstein DL, et al. Neuroinflammation in Alzheimer’s disease.
Lancet Neurol. 2015;14(4):388-405. doi: 10.1016/S1474-
4422(15)70016-5.
15. Chin-Chan M, Navarro-Yepes J, Quintanilla-Vega B.
Environmental pollutants as risk factors for neurodegenerative
disorders: Alzheimer and Parkinson diseases. Front Cell
Neurosci. 2015;9:124. doi: 10.3389/fncel.2015.00124.
16. Arnold SE, Arvanitakis Z, Macauley-Rambach SL, Koenig AM,
Wang HY, Ahima RS, et al. Brain insulin resistance in type 2
diabetes and Alzheimer disease: concepts and conundrums.
Nat Rev Neurol. 2018;14(3):168-181. doi: 10.1038/
nrneurol.2017.185.
17. Qiu C, Fratiglioni L. Aging without dementia is achievable:
current evidence from epidemiological research. J Alzheimers
Dis. 2018;62(3):933-942. doi: 10.3233/JAD-171037.
18. Ernst E. Herbal medicines–they are popular, but are they also
safe? Eur J Clin Pharmacol. 2006;62(1):1-2. doi: 10.1007/
s00228-005-0070-2.
19. José Bagur M, Alonso Salinas GL, Jiménez-Monreal AM,
Chaouqi S, Llorens S, Martínez-Tomé M, et al. Saffron: An
old medicinal plant and a potential novel functional food.
Molecules. 2017;23(1):30. doi: 10.3390/molecules23010030.
20. Akhondzadeh S, Abbasi SH. Herbal medicine in the treatment
of Alzheimer’s disease. Am J Alzheimers Dis Other Demen.
2006;21(2):113-8. doi: 10.1177/153331750602100211.
21. Schmidt M, Betti G, Hensel A. Saffron in phytotherapy:
pharmacology and clinical uses. Wien Med Wochenschr.
2007;157(13-14):315-9. doi: 10.1007/s10354-007-0428-4.
22. Fatehi M, Rashidabady T, Fatehi-Hassanabad Z. Effects of
Crocus sativus petals’ extract on rat blood pressure and on
responses induced by electrical field stimulation in the rat
isolated vas deferens and guinea-pig ileum. J Ethnopharmacol.
2003;84(2-3):199-203. doi: 10.1016/s0378-8741(02)00299-
4.
23. Sachdeva J, Tanwar V, Golechha M, Siddiqui KM, Nag TC, Ray
R, et al. Crocus sativus L.(saffron) attenuates isoproterenol-
induced myocardial injury via preserving cardiac functions
and strengthening antioxidant defense system. Exp Toxicol
Pathol. 2012;64(6):557-64. doi: 10.1016/j.etp.2010.11.013.
24. Khorasanchi Z, Shafiee M, Kermanshahi F, Khazaei
M, Ryzhikov M, Parizadeh MR, et al. Crocus sativus a
natural food coloring and flavoring has potent anti-tumor
properties. Phytomedicine. 2018;43:21-27. doi: 10.1016/j.
phymed.2018.03.041
25. Yaribeygi H, Zare V, Butler AE, Barreto GE, Sahebkar A.
Antidiabetic potential of saffron and its active constituents. J
Cell Physiol. 2019;234(6):8610-8617. doi: 10.1002/jcp.27843
26. Wali AF, Alchamat HAA, Hariri HK, Hariri BK, Menzes GA,
Zehra U, et al. Antioxidant, Antimicrobial, Antidiabetic
and Cytotoxic Activity of Crocus sativus L. Petals. Applied
Sciences. 2020;10(4):1519. doi: 10.3390/app10041519
27. Moallem SA, Hariri AT, Mahmoudi M, Hosseinzadeh H.
Effect of aqueous extract of Crocus sativus L.(saffron) stigma
against subacute effect of diazinon on specific biomarkers
in rats. Toxicol Ind Health. 2014;30(2):141-146. doi:
10.1177/0748233712452609
28. Bani S, Pandey A, Agnihotri VK, Pathania V, Singh B. Selective
Th2 upregulation by Crocus sativus: a neutraceutical spice.
Evid Based Complement Alternat Med. 2011;2011. doi:
10.1155/2011/639862
29. Bayrami G, Boskabady M. The potential effect of the extract of
Crocus sativus and safranal on the total and differential white
blood cells of ovalbumin-sensitized guinea pigs. Res Pharm
Sci. 2012;7(4):249.
30. Halataei BaS, Khosravi M, Arbabian S, Sahraei H, Golmanesh
L, Zardooz H, et al. Saffron (Crocus sativus) aqueous extract
and its constituent crocin reduces stress‐induced anorexia
in mice. Phytother Res. 2011;25(12):1833-8. doi: 10.1002/
ptr.3495
31. Byrami G, Boskabady MH, Jalali S, Farkhondeh T. The effect of
the extract of Crocus sativus on tracheal responsiveness and
plasma levels of IL-4, IFN-γ, total NO and nitrite in ovalbumin
sensitized Guinea-pigs. J Ethnopharmacol. 2013;147(2):530-
5. doi: 10.1016/j.jep.2013.03.014
32. Mohammadzadeh-Moghadam H, Nazari SM, Shamsa A,
Kamalinejad M, Esmaeeli H, Asadpour AA, et al. Effects of a
topical saffron (Crocus sativus L) gel on erectile dysfunction
in diabetics: A randomized, parallel-group, double-blind,
placebo-controlled trial. J Evid Based Complementary Altern
Med. 2015;20(4):283-286. doi: 10.1177/2156587215583756
33. Lopresti AL, Smith SJ, Hood SD, Drummond PD. Efficacy
of a standardised saffron extract (affron®) as an add-on to
antidepressant medication for the treatment of persistent
depressive symptoms in adults: A randomised, double-
blind, placebo-controlled study. J Psychopharmacol.
2019;33(11):1415-27. doi: 10.1177/0269881119867703
34. Hosseinzadeh H, Talebzadeh F. Anticonvulsant evaluation of
safranal and crocin from Crocus sativus in mice. Fitoterapia.
2005;76(7-8):722-4. doi: 10.1016/j.fitote.2005.07.008
35. Amin B, Malekzadeh M, Heidari MR, Hosseinzadeh H. Effect
of Crocus sativus extracts and its active constituent safranal on
the harmaline-induced tremor in mice. Iran J Basic Med Sci.
2015;18(5):449.
36. Hosseinzadeh H, Jahanian Z. Effect of Crocus sativus L.(saffron)
stigma and its constituents, crocin and safranal, on morphine
withdrawal syndrome in mice. Phytother Res. 2010;24(5):726-
30. doi: 10.1002/ptr.3011
37. Hosseinzadeh H, Khosravan V. Anticonvulsant effect of
aqueous and ethanolic extracts of Crocus sativus l stigmas in
mice. BMC Pharmacol. 2002. doi: 10.1186/1471-2210-2-7
38. Sadeghnia HR, Kamkar M, Assadpour E, Boroushaki MT,
Ghorbani A. Protective effect of safranal, a constituent of
Crocus sativus, on quinolinic acid-induced oxidative damage
in rat hippocampus. Iran J Basic Med Sci. 2013;16(1):73.
39. Ahmad AS, Ansari MA, Ahmad M, Saleem S, Yousuf S, Hoda
Arch Iran Med, Volume 24, Issue 3, March 2021 247
Saffron and its Derivatives in Alzheimer’s Disease
MN, et al. Neuroprotection by crocetin in a hemi-parkinsonian
rat model. Pharmacol Biochem Behav. 2005;81(4):805-13.
doi: 10.1016/j.pbb.2005.06.007
40. Saleem S, Ahmad M, Ahmad AS, Yousuf S, Ansari MA, Khan
MB, et al. Effect of Saffron (Crocus sativus) on neurobehavioral
and neurochemical changes in cerebral ischemia in rats. J
Med Food. 2006;9(2):246-53. doi: 10.1089/jmf.2006.9.246
41. Linardaki ZI, Orkoula MG, Kokkosis AG, Lamari FN, Margarity
M. Investigation of the neuroprotective action of saffron
(Crocus sativus L.) in aluminum-exposed adult mice through
behavioral and neurobiochemical assessment. Food Chem
Toxicol. 2013;52:163-70. doi: 10.1016/j.fct.2012.11.016
42. Fernández-Albarral JA, Ramírez AI, de Hoz R, López-Villarín
N, Salobrar-García E, López-Cuenca I, et al. Neuroprotective
and Anti-Inflammatory Effects of a Hydrophilic Saffron Extract
in a Model of Glaucoma. Int J Mol Sci. 2019;20(17):4110. doi:
10.3390/ijms20174110
43. Fernández-Albarral JA, de Hoz R, Ramírez AI, López-Villarín
N, Salobrar-García E, López-Cuenca I, et al. Beneficial effects
of saffron (Crocus sativus L.) in ocular pathologies, particularly
neurodegenerative retinal diseases. Neural Regen Res.
2020;15(8):1408-16. doi: 10.4103/1673-5374.274325
44. Broadhead GK, Grigg JR, McCluskey P, Hong T, Schlub TE,
Chang AA. Saffron therapy for the treatment of mild/moderate
age-related macular degeneration: a randomised clinical trial.
Graefes Arch Clin Exp Ophthalmol. 2019;257(1):31-40. doi:
10.1007/s00417-018-4163-x
45. Abe K, Sugiura M, Shoyama Y, Saito H. Crocin antagonizes
ethanol inhibition of NMDA receptor-mediated responses in
rat hippocampal neurons. Brain Res. 1998;787(1):132-8. doi:
10.1016/s0006-8993(97)01505-9
46. Sreenu G, Banala RR, Reddy KP. Saffron extract’s protective
effects against arsenic induced excitotoxicity and learning
disabilities in male Wistar rats. Int J Bioassay. 2015;4:4223-9.
doi:10.21746/IJBIO.2015.08.0012
47. Naghibi SM, Hosseini M, Khani F, Rahimi M, Vafaee F,
Rakhshandeh H, et al. Effect of aqueous extract of Crocus
sativus L. on morphine-induced memory impairment. Adv
Pharmacol Sci. 2012;2012. doi: 10.1155/2012/494367
48. Georgiadou G, Grivas V, Tarantilis PA, Pitsikas N. Crocins, the
active constituents of Crocus sativus L., counteracted ketamine–
induced behavioural deficits in rats. Psychopharmacology
(Berl). 2014;231(4):717-26. doi: 10.1007/s00213-013-3293-4
49. Papandreou MA, Kanakis CD, Polissiou MG, Efthimiopoulos
S, Cordopatis P, Margarity M, et al. Inhibitory activity on
amyloid-β aggregation and antioxidant properties of Crocus
sativus stigmas extract and its crocin constituents. J Agric Food
Chem. 2006;54(23):8762-8. doi: 10.1021/jf061932a
50. Al-Snafi AE. The pharmacology of Crocus sativus-A review.
IOSR Journal of Pharmacy. 2016;6(6):8-38.
51. Bukhari SI, Manzoor M, Dhar M. A comprehensive review
of the pharmacological potential of Crocus sativus and
its bioactive apocarotenoids. Biomed Pharmacother.
2018;98:733-45. doi: 10.1016/j.biopha.2017.12.090
52. Mykhailenko O, Kovalyov V, Goryacha O, Ivanauskas
L, Georgiyants V. Biologically active compounds and
pharmacological activities of species of the genus Crocus:
A review. Phytochemistry. 2019;162:56-89. doi: 10.1016/j.
phytochem.2019.02.004
53. Heitmar R, Brown J, Kyrou I. Saffron (Crocus sativus L.) in
ocular diseases: A narrative review of the existing evidence
from clinical studies. Nutrients. 2019;11(3):649. doi: 10.3390/
nu11030649
54. Lautenschläger M, Sendker J, Hüwel S, Galla HJ, Brandt S,
Düfer M, et al. Intestinal formation of trans-crocetin from
saffron extract (Crocus sativus L.) and in vitro permeation
through intestinal and blood brain barrier. Phytomedicine.
2015;22(1):36-44. doi: 10.1016/j.phymed.2014.10.009
55. Xi L, Qian Z, Du P, Fu J. Pharmacokinetic properties of crocin
(crocetin digentiobiose ester) following oral administration
in rats. Phytomedicine. 2007;14(9):633-636. doi: 10.1016/j.
phymed.2006.11.028
56. Yang N, Sun RB, Chen XL, Zhen L, Ge C, Zhao YQ, et al.
In vitro assessment of the glucose-lowering effects of
berberrubine-9-O-β-D-glucuronide, an active metabolite of
berberrubine. Acta Pharmacol Sin. 2017;38(3):351-61. doi:
10.1038/aps.2016.120
57. Asai A, Nakano T, Takahashi M, Nagao A. Orally administered
crocetin and crocins are absorbed into blood plasma as
crocetin and its glucuronide conjugates in mice. J Agric Food
Chem. 2005;53(18):7302-6. doi: 10.1021/jf0509355
58. Hosseini A, Razavi BM, Hosseinzadeh H. Pharmacokinetic
properties of saffron and its active components. Eur J Drug
Metab Pharmacokinet. 2018;43(4):383-90. doi: 10.1007/
s13318-017-0449-3
59. Christodoulou E, Grafakou ME, Skaltsa E, Kadoglou N,
Kostomitsopoulos N, Valsami G. Preparation, chemical
characterization and determination of crocetin’s
pharmacokinetics after oral and intravenous administration
of saffron (Crocus sativus L.) aqueous extract to C57/BL 6J
mice. J Pharm Pharmacol. 2019;71(5):753-64. doi: 10.1111/
jphp.13055
60. O’Brien RJ, Wong PC. Amyloid precursor protein processing
and Alzheimer’s disease. Annu Rev Neurosci. 2011;34:185-
204. doi: 10.1146/annurev-neuro-061010-113613
61. Harkany T, Abraham I, Timmerman W, Laskay G, Tóth B,
Sasvári M, et al. β-Amyloid neurotoxicity is mediated by a
glutamate‐triggered excitotoxic cascade in rat nucleus basalis.
Eur J Neurosci. 2000;12(8):2735-45. doi: 10.1046/j.1460-
9568.2000.00164.x
62. Qiu C, Kivipelto M, von Strauss E. Epidemiology of Alzheimer’s
disease: occurrence, determinants, and strategies toward
intervention. Dialogues Clin Neurosci. 2009;11(2):111. doi:
10.31887/DCNS.2009.11.2/cqiu
63. Kirkitadze MD, Kowalska A. Molecular mechanisms initiating
amyloid beta-fibril formation in Alzheimer’s disease. Acta
Biochim Pol. 2005;52(2):417-423.
64. Shankar GM, Walsh DM. Alzheimer’s disease: synaptic
dysfunction and Aβ. Mol Neurodegener. 2009;4(1):48. doi:
10.1186/1750-1326-4-48
65. Sadigh-Eteghad S, Talebi M, Farhoudi M, Golzari SE,
Sabermarouf B, Mahmoudi J. Beta-amyloid exhibits
antagonistic effects on alpha 7 nicotinic acetylcholine receptors
in orchestrated manner. Journal of Medical Hypotheses and
Ideas. 2014;8(2):49-52. doi: 10.1016/j.jmhi.2014.01.001
66. Kontush A, Berndt C, Weber W, Akopyan V, Arlt S, Schippling
S, et al. Amyloid-β is an antioxidant for lipoproteins in
cerebrospinal fluid and plasma. Free Radic Biol Med..
2001;30(1):119-28. doi: 10.1016/s0891-5849(00)00458-5
67. Nunomura A, Castellani RJ, Lee H-g, Moreira PI, Zhu X, Perry
G et al. Neuropathology in Alzheimer’s disease: awaking from
a hundred-year-old dream. Sci Aging Knowledge Environ.
2006;8:e10. doi: 10.1126/sageke.2006.8.pe10
68. Vinters HV. Cerebral amyloid angiopathy. A critical review.
Stroke. 1987;18(2):311-24. doi: 10.1161/01.str.18.2.311
69. Ellis R, Olichney JM, Thal L, Mirra SS, Morris JC, Beekly D
et al. Cerebral amyloid angiopathy in the brains of patients
with Alzheimer’s disease: the CERAD experience, Part XV.
Neurology. 1996;46(6):1592-6. doi: 10.1212/wnl.46.6.1592
70. Attems J, Yamaguchi H, Saido TC, Thal DR. Capillary CAA and
perivascular Aβ-deposition: two distinct features of Alzheimer’s
disease pathology. J Neurol Sci. 2010;299(1-2):155-62. doi:
10.1016/j.jns.2010.08.030
71. Kihara T, Shimohama S. Alzheimer’s disease and acetylcholine
receptors. Acta Neurobiol Exp (Wars). 2004;64(1):99-106.
72. Sadigh-Eteghad S, Sabermarouf B, Majdi A, Talebi M,
Arch Iran Med, Volume 24, Issue 3, March 2021
248
Zandi et al
Farhoudi M, Mahmoudi J. Amyloid-beta: a crucial factor in
Alzheimer’s disease. Med Princ Pract. 2015;24(1):1-10. doi:
10.1159/000369101
73. Ridolfi E, Barone C, Scarpini E, Galimberti D. The role
of the innate immune system in Alzheimer’s disease and
frontotemporal lobar degeneration: an eye on microglia. Clin
Dev Immunol. 2013;2013. doi: 10.1155/2013/939786
74. Balducci C, Beeg M, Stravalaci M, Bastone A, Sclip A, Biasini E,
et al. Synthetic amyloid-β oligomers impair long-term memory
independently of cellular prion protein Proc Natl Acad Sci U
S A. 2010;107(5):2295-2300. doi: 10.1073/pnas.0911829107
75. Barry AE, Klyubin I, Mc Donald JM, Mably AJ, Farrell MA, Scott
M, et al. Alzheimer’s disease brain-derived amyloid-β-mediated
inhibition of LTP in vivo is prevented by immunotargeting
cellular prion protein. J Neurosci. 2011;31(20):7259-63. doi:
10.1523/JNEUROSCI.6500-10.2011
76. Shen CL, Fitzgerald MC, Murphy RM. Effect of acid
predissolution on fibril size and fibril flexibility of synthetic
beta-amyloid peptide. Biophys J. 1994;67(3):1238-46.
doi:10.1016/S0006-3495(94)80593-4
77. Hardy J, Selkoe DJ. The amyloid hypothesis of Alzheimer’s
disease: progress and problems on the road to therapeutics.
Science. 2002;297(5580):353-6. doi: 10.1126/
science.1072994.
78. Kittelberger KA, Piazza F, Tesco G, Reijmers LG. Natural
amyloid-beta oligomers acutely impair the formation of a
contextual fear memory in mice. PLoS One. 2012;7(1):e29940.
doi: 10.1371/journal.pone.0029940.
79. Davidowitz EJ, Chatterjee I, Moe JG. Targeting tau oligomers
for therapeutic development for Alzheimer’s disease and
tauopathies. Biotechnology. 2008;4:47-64.
80. Götz J, Probst A, Spillantini MG, Schäfer T, Jakes R, Bürki K, et
al. Somatodendritic localization and hyperphosphorylation of
tau protein in transgenic mice expressing the longest human
brain tau isoform. EMBO J. 1995;14(7):1304-1313.
81. Buée L, Bussière T, Buée-Scherrer V, Delacourte A, Hof
PR. Tau protein isoforms, phosphorylation and role in
neurodegenerative disorders. Brain Res Brain Res Rev.
2000;33(1):95-130. doi: 10.1016/s0165-0173(00)00019-9
82. Brion J-P. Neurofibrillary tangles and Alzheimer’s disease. Eur
Neurol. 1998;40(3):130-40. doi: 10.1159/000007969
83. Kimura T, Yamashita S, Fukuda T, Park JM, Murayama M,
Mizoroki T et al. Hyperphosphorylated tau in parahippocampal
cortex impairs place learning in aged mice expressing wild-
type human tau. EMBO J. 2007;26(24):5143-52. doi: 10.1038/
sj.emboj.7601917
84. Kimura T, Whitcomb DJ, Jo J, Regan P, Piers T, Heo S, et al.
Microtubule-associated protein tau is essential for long-term
depression in the hippocampus. Philos Trans R Soc Lond B Biol
Sci. 2014;369(1633):20130144. doi: 10.1098/rstb.2013.0144
85. Mohorko N, Bresjanac M. Tau protein and human tauopathies:
an overwiev. Slovenian Medical Journal. 2008;77.
86. Goedert M, Spillantini MG. A century of Alzheimer’s
disease. Science. 2006;314(5800):777-81. doi: 10.1126/
science.1132814.
87. Braak H, Del Tredici K. Where, when, and in what form
does sporadic Alzheimer’s disease begin? Curr Opin Neurol.
2012;25(6):708-14. doi: 10.1097/WCO.0b013e32835a3432
88. Santa-Maria I, Haggiagi A, Liu X, Wasserscheid J, Nelson
PT, Dewar K, et al. The MAPT H1 haplotype is associated
with tangle-predominant dementia. Acta neuropathol.
2012;124(5):693-704. doi: 10.1007/s00401-012-1017-1
89. Haan MN, Shemanski L, Jagust WJ, Manolio TA, Kuller L.
The role of apoe epsilon4 in modulating effects of other risk
factors for cognitive decline in elderly persons. Neuroimage.
2018;172:118-29. doi: 10.1016/j.neuroimage.2017.12.027.
90. Lahoz C, Schaefer EJ, Cupples LA, Wilson PW, Levy D, Osgood
D, et al. Apolipoprotein E genotype and cardiovascular
disease in the Framingham Heart Study. Atherosclerosis.
2001;154(3):529-37. doi: 10.1016/s0021-9150(00)00570-0
91. Mahley RW, Rall SC Jr. Apolipoprotein E: far more than a
lipid transport protein. Annu Rev Genomics Hum Genet.
2000;1(1):507-37. doi: 10.1146/annurev.genom.1.1.507
92. Peila R, Rodriguez BL, Launer LJ. Type 2 diabetes, APOE
gene, and the risk for dementia and related pathologies: The
Honolulu-Asia Aging Study. Diabetes. 2002;51(4):1256-62.
doi: 10.2337/diabetes.51.4.1256
93. Corder EH, Saunders AM, Strittmatter WJ, Schmechel DE,
Gaskell PC, Small GW, et al. Gene dose of apolipoprotein E
type 4 allele and the risk of Alzheimer’s disease in late onset
families. Science. 1993;261(5123):921-3. doi: 10.1126/
science.8346443.
94. Farrer LA, Cupples LA, Haines JL, Hyman B, Kukull WA,
Mayeux R, et al. Effects of age, sex, and ethnicity on the
association between apolipoprotein E genotype and Alzheimer
disease: a meta-analysis. JAMA. 1997;278(16):1349-56.
95. Talbot C, Lendon C, Craddock N, Shears S, Morris JC, Goate
A. Protection against Alzheimer’s disease with apoE epsilon2.
Lancet. 1994:1432-2. doi: 10.1016/s0140-6736(94)92557-7
96. Harold D, Abraham R, Hollingworth P, Sims R, Gerrish A,
Hamshere ML, et al. Erratum: Genome-wide association
study identifies variants at CLU and PICALM associated with
Alzheimer’s disease (Nature Genetics)(2009) 41 (1088-1093).
Nat Genet. 2009;41(10). doi: 10.1038/ng.440
97. Lambert JC, Heath S, Even G, Campion D, Sleegers K, Hiltunen
M, et al. Genome-wide association study identifies variants at
CLU and CR1 associated with Alzheimer’s disease. Nat Genet.
2009;41(10):1094. doi: 10.1038/ng.440
98. Hauser PS, Ryan RO. Impact of apolipoprotein E on
Alzheimer’s disease. Curr Alzheimer Res. 2013;10(8):809-17.
doi: 10.2174/15672050113109990156
99. Glorioso CA, Pfenning AR, Lee SS, Bennett DA, Sibille EL,
Kellis M, et al. Rate of brain aging and APOE ε4 are synergistic
risk factors for Alzheimer’s disease. Life Sci Alliance.
2019;2(3):e201900303. doi: 10.26508/lsa.201900303.
100. Bales KR, Liu F, Wu S, Lin S, Koger D, DeLong C, et al. Human
APOE isoform-dependent effects on brain β-amyloid levels in
PDAPP transgenic mice. J Neurosci. 2009;29(21):6771-9. doi:
10.1523/JNEUROSCI.0887-09.2009
101. Castellano JM, Kim J, Stewart FR, Jiang H, DeMattos RB,
Patterson BW, et al. Human apoE isoforms differentially
regulate brain amyloid-β peptide clearance. Sci Transl Med.
2011;3(89):89ra57. doi: 10.1126/scitranslmed.3002156
102. Huang Y-WA, Zhou B, Wernig M, Südhof TC. ApoE2, ApoE3,
and ApoE4 differentially stimulate APP transcription and Aβ
secretion. Cell. 2017;168(3):427-441.e421. doi: 10.1016/j.
cell.2016.12.044
103. Bales KR, Verina T, Dodel RC, Du Y, Altstiel L, Bender M et
al. Lack of apolipoprotein E dramatically reduces amyloid
β-peptide deposition. Nat Genet. 1997;17(3):263-4. doi:
10.1038/ng1197-263
104. Kok E, Haikonen S, Luoto T, Huhtala H, Goebeler S, Haapasalo
H, et al. Apolipoprotein E–dependent accumulation of
Alzheimer disease–related lesions begins in middle age. Ann
Neurol. 2009;65(6):650-7. doi: 10.1002/ana.21696
105. Polvikoski T, Sulkava R, Haltia M, Kainulainen K, Vuorio
A, Verkkoniemi A et al. Apolipoprotein E, dementia, and
cortical deposition of β-amyloid protein. N Engl J Med.
1995;333(19):1242-8. doi: 10.1073/pnas.90.20.9649
106. Schmechel D, Saunders A, Strittmatter W, Crain BJ, Hulette
CM, Joo SH, et al. Increased amyloid beta-peptide deposition
in cerebral cortex as a consequence of apolipoprotein E
genotype in late-onset Alzheimer disease. Proc Natl Acad Sci
U S A. 1993;90(20):9649-53. doi: 10.1073/pnas.90.20.9649
107. Berlau DJ, Corrada MM, Head E, Kawas CH. APOE ε2 is
associated with intact cognition but increased Alzheimer
Arch Iran Med, Volume 24, Issue 3, March 2021 249
Saffron and its Derivatives in Alzheimer’s Disease
pathology in the oldest old. Neurology. 2009;72(9):829-34.
doi: 10.1212/01.wnl.0000343853.00346.a4
108. Etnier JL, Caselli RJ, Reiman EM, Alexander GE, Sibley BA,
Tessier D, et al. Cognitive performance in older women
relative to ApoE-ε4 genotype and aerobic fitness. Med
Sci Sports Exerc. 2007;39(1):199-207. doi: 10.1249/01.
mss.0000239399.85955.5e
109. Brown BM, Peiffer J, Taddei K, Lui JK, Laws SM, Gupta VB, et
al. Physical activity and amyloid-β plasma and brain levels:
results from the Australian Imaging, Biomarkers and Lifestyle
Study of Ageing. Mol Psychiatry. 2013;18(8):875-881. doi:
10.1038/mp.2012.107
110. Head D, Bugg JM, Goate AM, Fagan AM, Mintun MA,
Benzinger ,T et al. Exercise engagement as a moderator of the
effects of APOE genotype on amyloid deposition. Arch Neurol.
2012;69(5):636-43. doi: 10.1001/archneurol.2011.845
111. Berkowitz C, Mosconi L, Rahman A, Scheyer O, Hristov H,
Isaacson RS. Clinical application of APOE in Alzheimer’s
prevention: a precision medicine approach. J Prev Alzheimers
Dis. 2018;5(4):245-52. doi: 10.14283/jpad.2018.35
112. Durazzo TC, Mattsson N, Weiner MW, Initiative AsDN.
Interaction of cigarette smoking history with apoe genotype
and age on amyloid level, glucose metabolism, and
neurocognition in cognitively normal elders. Nicotine Tob
Res. 2015;18(2):204-11. doi: 10.1093/ntr/ntv075
113. Kivipelto M, Rovio S, Ngandu T, Kåreholt I, Eskelinen M,
Winblad B, et al. Apolipoprotein E ɛ4 magnifies lifestyle
risks for dementia: a population-based study. J Cell
Mol Med. 2008;12(6b):2762-71. doi: 10.1111/j.1582-
4934.2008.00296.x
114. Downer B, Zanjani F, Fardo DW. The relationship between
midlife and late life alcohol consumption, APOE e4 and the
decline in learning and memory among older adults. Alcohol
Alcohol. 2014;49(1):17-22. doi: 10.1093/alcalc/agt144
115. Premkumar K, Abraham SK, Santhiya S, Ramesh A. Protective
effects of saffron (Crocus sativus Linn.) on genotoxins-
induced oxidative stress in Swiss albino mice. Phytother Res.
2003;17(6):614-17. doi: 10.1002/ptr.1209
116. Soeda S, Aritake K, Urade Y, Sato H, Shoyama Y.
Neuroprotective activities of saffron and crocin. The Benefits
of Natural Products for Neurodegenerative Diseases: Springer;
2016:275-92. doi:10.1007/978-3-319-28383-8_14
117. Batish D, Singh H, Setia N, Kaur S, Kohli R. 2-Benzoxazolinone
(BOA) induced oxidative stress, lipid peroxidation and
changes in some antioxidant enzyme activities in mung bean
(Phaseolus aureus). Plant Physiol Biochem. 2006;44(11-
12):819-27. doi: 10.1016/j.plaphy.2006.10.014
118. Bodnoff SR, Humphreys AG, Lehman JC, Diamond
DM, Rose GM, Meaney MJ. Enduring effects of chronic
corticosterone treatment on spatial learning, synaptic
plasticity, and hippocampal neuropathology in young and
mid-aged rats. J Neurosci. 1995;15(1):61-9. doi: 10.1523/
JNEUROSCI.15-01-00061.1995
119. Zafir A, Banu N. Modulation of in vivo oxidative status by
exogenous corticosterone and restraint stress in rats. Stress.
2009;12(2):167-177. doi: 10.1080/10253890802234168
120. Galea L, McEwen B, Tanapat P, Deak T, Spencer R, Dhabhar
F. Sex differences in dendritic atrophy of CA3 pyramidal
neurons in response to chronic restraint stress. Neuroscience.
1997;81(3):689-97. doi: 10.1016/s0306-4522(97)00233-9
121. Magariños AMa, Orchinik M, McEwen BS. Morphological
changes in the hippocampal CA3 region induced by non-
invasive glucocorticoid administration: a paradox. Brain Res.
1998;809(2):314-8. doi: 10.1016/s0006-8993(98)00882-8
122. Asdaq SMB, Inamdar MN. Potential of Crocus sativus (saffron)
and its constituent, crocin, as hypolipidemic and antioxidant
in rats. Appl Biochem Biotechnol. 2010;162(2):358-72. doi:
10.1007/s12010-009-8740-7
123. Kanakis C, Tarantilis P, Pappas C, Bariyanga J, Tajmir-Riahi
H, Polissiou M. An overview of structural features of DNA
and RNA complexes with saffron compounds: Models and
antioxidant activity. J Photochem Photobiol B. 2009;95(3):204-
12. doi: 10.1016/j.jphotobiol.2009.03.006
124. Das SK, Prusty A, Samantaray D, Hasan M, Jena S, Patra
JK, et al. Effect of Xylocarpus granatum Bark Extract on
Amelioration of Hyperglycaemia and Oxidative Stress
Associated Complications in STZ-Induced Diabetic Mice.
Evid Based Complement Alternat Med. 2019;2019:8493190.
doi: 10.1155/2019/8493190.
125. Aydin Dilsiz S, Bacanli M, Anlar H, Çal T, Arı N, Ündeğer
Bucurgat Ü, et al. Preventive role of Pycnogenol (R) against
the hyperglycemia-induced oxidative stress and DNA damage
in diabetic rats. Food Chem Toxicol. 2019 Feb;124:54-63. doi:
10.1016/j.fct.2018.11.038.
126. Del-Angel D, Martínez N, Cruz M, Urrutia E, Riverón-Negrete
L, Abdullaev F. Saffron extract ameliorates oxidative damage
and mitochondrial dysfunction in the rat brain. Paper presented
at: II International Symposium on Saffron Biology and
Technology 7392006. doi: 10.17660/ActaHortic.2007.739.47
127. Sh A, El-Azime A, NH S, N A E. Efficacy of aqueous extract
of saffron (Crocus sativus L.) in modulating radiation-induced
brain and eye retina damage in rats. The Egyptian Journal of
Hospital Medicine. 2014;54(1):101-8. doi: 10.12816/0002436
128. Finley JW, Gao S. A perspective on Crocus sativus L. (Saffron)
constituent crocin: a potent water-soluble antioxidant and
potential therapy for Alzheimer’s disease. J Agric Food Chem.
2017;65(5):1005-20. doi: 10.1021/acs.jafc.6b04398
129. Chen L, Qi Y, Yang X. Neuroprotective effects of crocin
against oxidative stress induced by ischemia/reperfusion
injury in rat retina. Ophthalmic Res. 2015;54(3):157-68. doi:
10.1159/000439026
130. Rahiman N, Akaberi M, Sahebkar A, Emami SA, Tayarani-
Najaran Z. Protective effects of saffron and its active
components against oxidative stress and apoptosis in
endothelial cells. Microvasc Res. 2018;118:82-9. doi:
10.1016/j.mvr.2018.03.003
131. Ibach B, Haen E. Acetylcholinesterase inhibition in
Alzheimer’s Disease. Curr Pharm Des. 2004;10(3):231-51.
doi: 10.2174/1381612043386509
132. Mega MS. The cholinergic deficit in Alzheimer’s disease:
impact on cognition, behaviour and function. Int J
Neuropsychopharmacol. 2000;3(Supplement_2):S3-S12. doi:
10.1017/S1461145700001942
133. Birks JS. Cholinesterase inhibitors for Alzheimer’s disease.
Cochrane Database Syst Rev. 2006;(1):CD005593. doi:
10.1002/14651858.CD005593.
134. Howland RH. Drug therapies for cognitive impairment
and dementia. J Psychosoc Nurs Ment Health Serv. Journal
of psychosocial nursing and mental health services.
2010;48(4):11-4. doi: 10.3928/02793695-20100311-01
135. Ademosun AO, Oboh G. Inhibition of acetylcholinesterase
activity and Fe2+-induced lipid peroxidation in rat brain in
vitro by some citrus fruit juices. J Med Food. 2012;15(5):428-
34. doi: 10.1089/jmf.2011.0226
136. Papandreou MA, Tsachaki M, Efthimiopoulos S, Cordopatis P,
Lamari FN, Margarity M. Memory enhancing effects of saffron
in aged mice are correlated with antioxidant protection.
Behav Brain Res. 2011;219(2):197-204. doi: 10.1016/j.
bbr.2011.01.007
137. Rafieipour F, Hadipour E, Emami SA, Asili J, Tayarani-Najaran
Z. Safranal protects against beta-amyloid peptide-induced
cell toxicity in PC12 cells via MAPK and PI3 K pathways.
Metab Brain Dis. 2019;34(1):165-72. doi: 10.1016/j.
pbb.2015.10.011
138. Rashedinia M, Lari P, Abnous K, Hosseinzadeh H. Protective
effect of crocin on acrolein-induced tau phosphorylation in
Arch Iran Med, Volume 24, Issue 3, March 2021
250
Zandi et al
the rat brain. Acta Neurobiol Exp (Wars). 2015;75(2):208-19.
139. Kirouac L, Rajic AJ, Cribbs DH, Padmanabhan J. Activation of
Ras-ERK signaling and GSK-3 by amyloid precursor protein
and amyloid beta facilitates neurodegeneration in Alzheimer’s
disease. eNeuro. 2017 Mar 27;4(2):ENEURO.0149-16.2017.
doi: 10.1523/ENEURO.0149-16.2017.
140. Ghahghaei A, Bathaie SZ, Bahraminejad E. Mechanisms
of the effects of crocin on aggregation and deposition of
Aβ1–40 fibrils in Alzheimer’s disease. Int J Pept Res The.
2012;18(4):347-51. doi: 10.1007/s10989-012-9308-x
141. Ghahghaei A, Bathaie SZ, Kheirkhah H, Bahraminejad E. The
protective effect of crocin on the amyloid fibril formation of
Aβ42 peptide in vitro. Cell Mol Biol Lett. 2013;18(3):328-39.
doi: 10.2478/s11658-013-0092-1
142. Morelli S, Salerno S, Piscioneri A, Tasselli F, Drioli E, De
Bartolo L. Neuronal membrane bioreactor as a tool for testing
crocin neuroprotective effect in Alzheimer’s disease. Chem
Eng J. 2016;305:69-78. doi:10.1016/j.cej.2016.01.035
143. Asadi F, Jamshidi AH, Khodagholi F, Yans A, Azimi L, Faizi
M, et al. Reversal effects of crocin on amyloid β-induced
memory deficit: modification of autophagy or apoptosis
markers. Pharmacol Biochem Behav. 2015;139(Pt A):47-58.
doi: 10.1016/j.pbb.2015.10.011.
144. Soeda S, Ochiai T, Paopong L, Tanaka H, Shoyama Y, Shimeno
H. Crocin suppresses tumor necrosis factor-α-induced cell
death of neuronally differentiated PC-12 cells. Life Sci.
2001;69(24):2887-98. doi: 10.1016/s0024-3205(01)01357-1
145. Baluchnejadmojarad T, Mohamadi-Zarch S-M, Roghani M.
Safranal, an active ingredient of saffron, attenuates cognitive
deficits in amyloid β-induced rat model of Alzheimer’s disease:
underlying mechanisms. Metab Brain Dis. 2019;34(6):1747-
59. doi: 10.1007/s11011-019-00481-6
146. Holsinger RD, McLean CA, Beyreuther K, Masters CL, Evin
G. Increased expression of the amyloid precursor β-secretase
in Alzheimer’s disease. Ann Neurol. 2002;51(6):783-6. doi:
10.1002/ana.10208
147. Kayed R, Lasagna-Reeves CA. Molecular mechanisms
of amyloid oligomers toxicity. J Alzheimers Dis.
2013;33(s1):S67-S78. doi: 10.3233/JAD-2012-129001
148. Batarseh YS, Bharate SS, Kumar V, Kumar A, Vishwakarma RA,
Bharate SB, et al. Crocus sativus extract tightens the blood-
brain barrier, reduces amyloid β load and related toxicity in
5XFAD mice. ACS Chem Neurosci. 2017;8(8):1756-66. doi:
10.1021/acschemneuro.7b00101
149. Karakani AM, Riazi G, Mahmood Ghaffari S, Ahmadian S,
Mokhtari F, Jalili Firuzi M, et al. Inhibitory effect of corcin on
aggregation of 1N/4R human tau protein in vitro. Iran J Basic
Med Sci. 2015;18(5):485-92.
150. Mohammadzadeh L, Abnous K, Razavi BM, Hosseinzadeh
H. Crocin-protected malathion-induced spatial memory
deficits by inhibiting TAU protein hyperphosphorylation and
antiapoptotic effects. Nutr Neurosci. 2020;23(3):221-236.
doi: 10.1080/1028415X.2018.1492772
151. Chawla A, Boisvert WA, Lee CH, Laffitte BA, Barak Y, Joseph
SB, et al. A PPARγ-LXR-ABCA1 pathway in macrophages is
involved in cholesterol efflux and atherogenesis. Mol Cell.
2001;7(1):161-71. doi: 10.1016/s1097-2765(01)00164-2
152. Qosa H, Abuasal BS, Romero IA, Weksler B, Couraud PO,
Keller JN, et al. Differences in amyloid-β clearance across
mouse and human blood–brain barrier models: kinetic
analysis and mechanistic modeling. Neuropharmacology.
2014;79:668-78. doi: 10.1016/j.neuropharm.2014.01.023
153. Wahrle SE, Jiang H, Parsadanian M, Han X, Fryer JD,
Kowalewski T, et al. ABCA1 is required for normal central
nervous system ApoE levels and for lipidation of astrocyte-
secreted apoE. J Biol Chem. 2004;279(39):40987-93. doi:
10.1074/jbc.M407963200
154. Akhondzadeh S, Sabet MS, Harirchian MH, Gougol A,
Yekehtaz H, Alimardani R, et al. A 22-week, multicenter,
randomized, double-blind controlled trial of Crocus sativus
in the treatment of mild-to-moderate Alzheimer’s disease.
Hum Psychopharmacol. 2010b;207(4):637-43. doi: 10.1002/
hup.2412
155. Farokhnia M, Shafiee Sabet M, Iranpour N, Gougol A, Yekehtaz
H, Alimardani R, et al. Comparing the efficacy and safety of
Crocus sativus L. with memantine in patients with moderate
to severe Alzheimer’s disease: a double-blind randomized
clinical trial. Hum Psychopharmacol. 2014;29(4):351-59. doi:
10.1002/hup.2412
156. Akhondzadeh S, Sabet MS, Harirchian M, Togha M,
Cheraghmakani H, Razeghi S, et al. Saffron in the treatment of
patients with mild to moderate Alzheimer’s disease: a 16-week,
randomized and placebo-controlled trial. J Clin Pharm Ther.
2010a;35(5):581-8. doi: 10.1111/j.1365-2710.2009.01133.x
157. Steiner GZ, Yeung A, Liu JX, Camfield DA, Blasio FM, Pipingas
A, et al. The effect of Sailuotong (SLT) on neurocognitive and
cardiovascular function in healthy adults: a randomised,
double-blind, placebo controlled crossover pilot trial. BMC
Complement Altern Med. 2015;16(1):15. doi: 10.1186/
s12906-016-0989-0
158. Tsolaki M, Karathanasi E, Lazarou I, Dovas K, Verykouki E,
Karacostas A, et al. Efficacy and safety of Crocus sativus L. in
patients with mild cognitive impairment: one year single-blind
randomized, with parallel groups, clinical trial. J Alzheimers
Dis. 2016;54(1):129-33. doi: 10.3233/JAD-160304
159. Dashti-r M, Zeinali F, Anvari M, Hosseini S. Saffron (Crocus
sativus L.) extract prevents and improves D-galactose and
NaNO2 induced memory impairment in mice. EXCLI J.
2012;11:328.
160. Ochiai T, Shimeno H, Mishima K-i, Iwasaki K, Fujiwara M,
Tanaka H, et al. Protective effects of carotenoids from saffron
on neuronal injury in vitro and in vivo. Biochim Biophys Acta.
2007;1770(4):578-84. doi: 10.1016/j.bbagen.2006.11.012
161. Tashakori-Sabzevar F, Hosseinzadeh H, Sadat Motamedshariaty
V, Reza Movassaghi A, Ahmad Mohajeri S. Crocetin attenuates
spatial learning dysfunction and hippocampal injury in a model
of vascular dementia. Curr Neurovasc Res. 2013;10(4):325-
334. doi: 10.2174/15672026113109990032
162. Hosseinzadeh H, Sadeghnia HR, Ghaeni FA, Motamedshariaty
VS, Mohajeri SA. Effects of saffron (Crocus sativus L.) and its
active constituent, crocin, on recognition and spatial memory
after chronic cerebral hypoperfusion in rats. Phytother Res.
2012;26(3):381-386. doi: 10.1002/ptr.3566
163. Zheng YQ, Liu JX, Wang JN, Xu L. Effects of crocin on
reperfusion-induced oxidative/nitrative injury to cerebral
microvessels after global cerebral ischemia. Brain Res.
2007;1138:86-94. doi: 10.1016/j.brainres.2006.12.064
164. Khalili M, Hamzeh F. Effects of active constituents of Crocus
sativus L., crocin on streptozocin-induced model of sporadic
Alzheimer’s disease in male rats. Iran Biomed J. 2010;14(1-
2):59.
165. Naghizadeh B, Mansouri M, Ghorbanzadeh B, Farbood
Y, Sarkaki A. Protective effects of oral crocin against
intracerebroventricular streptozotocin-induced spatial
memory deficit and oxidative stress in rats. Phytomedicine.
2013;20(6):537-42. doi: 10.1016/j.phymed.2012.12.019
166. amaddonfard E, Farshid AA, Asri-Rezaee S, Javadi S, Khosravi
V, Rahman B, et al. Crocin improved learning and memory
impairments in streptozotocin induced diabetic rats. Iran J
Basic Med Sci. 2013;16(1):91-100.
167. Moshahid Khan M, Ahmad A, Yusuf S, Islam F. Neuroprotective
efficacy of Nardostachys jatamansi and crocetin in
conjunction with selenium in cognitive impairment. Neurol
Sci. 2012;33(5):1011-20. doi: 10.1007/s10072-011-0880-1.
168. Bandegi AR, Rashidy-Pour A, Vafaei AA, Ghadrdoost B.
Protective effects of Crocus sativus L. extract and crocin
Arch Iran Med, Volume 24, Issue 3, March 2021 251
Saffron and its Derivatives in Alzheimer’s Disease
against chronic-stress induced oxidative damage of brain, liver
and kidneys in rats. Adv Pharm Bull. 2014;4(Suppl 2):493-9.
doi: 10.5681/apb.2014.073.
169. Ghadrdoost B, Vafaei AA, Rashidy-Pour A, Hajisoltani R,
Bandegi AR, Motamedi F, et al. Protective effects of saffron
extract and its active constituent crocin against oxidative stress
and spatial learning and memory deficits induced by chronic
stress in rats. Eur J Pharmacol. 2011;667(1-3):222-9. doi:
10.1016/j.ejphar.2011.05.012.
170. El-Beshbishy HA, Hassan MH, Aly HA, Doghish AS, Alghaithy
AA. Crocin “saffron” protects against beryllium chloride toxicity
in rats through diminution of oxidative stress and enhancing
gene expression of antioxidant enzymes. Ecotoxicol Environ
Saf. 2012;83:47-54. doi: 10.1016/j.ecoenv.2012.06.003
171. Pitsikas N, Zisopoulou S, Tarantilis PA, Kanakis CD, Polissiou
MG, Sakellaridis N. Effects of the active constituents of
Crocus sativus L., crocins on recognition and spatial rats’
memory. Behav Brain Res. 2007;183(2):141-6. doi: 10.1016/j.
bbr.2007.06.001
172. Pitsikas N, Sakellaridis N. Crocus sativus L. extracts antagonize
memory impairments in different behavioural tasks in the
rat. . Behav Brain Res. 2006;173(1):112-5. doi: 10.1016/j.
bbr.2006.06.005
173. Zhang Y, Shoyama Y, Sugiura M, Saito H. Effects of Crocus
sativus L. on the ethanol-induced impairment of passive
avoidance performances in mice. Biol Pharm Bull.
1994;17(2):217-21. doi: 10.1248/bpb.17.217
174. Sugiura M, Shoyama Y, Saito H, Nishiyama N. Crocin improves
the ethanol-induced impairment of learning behaviors of mice
in passive avoidance tasks. Proceedings of the Japan Academy,
Series B. 1995;71(10):319-24. doi:10.2183/pjab.71.319
175. Abe K, Sugiura M, Yamaguchi S, Shoyama Y, Saito H. Saffron
extract prevents acetaldehyde-induced inhibition of long-
term potentiation in the rat dentate gyrus in vivo. Brain Res.
1999;851(1-2):287-9. doi: 10.1016/s0006-8993(99)02174-5
176. Walton J, Wang MX. APP expression, distribution and
accumulation are altered by aluminum in a rodent model for
Alzheimer’s disease. J Inorg Biochem. 2009;103(11):1548-54.
doi: 10.1016/j.jinorgbio.2009.07.027
177. Xu Y, Wang Z, You W, Zhang X, Li S, Barish PA, et
al. Antidepressant-like effect of trans-resveratrol:
involvement of serotonin and noradrenaline system. Eur
Neuropsychopharmacol. 2010;20(6):405-13. doi: 10.1016/j.
euroneuro.2010.02.013
178. Yokel RA. Blood-brain barrier flux of aluminum, manganese,
iron and other metals suspected to contribute to metal-induced
neurodegeneration. J Alzheimers Dis. 2006;10(2-3):223-53.
doi: 10.3233/jad-2006-102-309
179. Zhang ZJ, Qian YH, Hu HT, Yang J, Yang GD. The herbal
medicine Dipsacus asper Wall extract reduces the cognitive
deficits and overexpression of β-amyloid protein induced
by aluminum exposure. Life Sci. 2003;73(19):2443-54. doi:
10.1016/s0024-3205(03)00649-0
180. Sethi P, Jyoti A, Singh R, Hussain E, Sharma D. Aluminium-
induced electrophysiological, biochemical and cognitive
modifications in the hippocampus of aging rats.
Neurotoxicology. 2008;29(6):1069-79. doi: 10.1016/j.
neuro.2008.08.005
181. Sharma D, Sethi P, Hussain E, Singh R. Curcumin counteracts
the aluminium-induced ageing-related alterations in oxidative
stress, Na+, K+ ATPase and protein kinase C in adult and old
rat brain regions. Biogerontology. 2009;10(4):489-502. doi:
10.1007/s10522-008-9195-x
182. Tripathi S, Mahdi AA, Nawab A, Chander R, Hasan M, Siddiqui
MS, Mahdi F, et al. Influence of age on aluminum induced lipid
peroxidation and neurolipofuscin in frontal cortex of rat brain:
a behavioral, biochemical and ultrastructural study. Brain Res.
2009;1253:107-16. doi: 10.1016/j.brainres.2008.11.060
183. Butterfield DA, Abdul HM, Newman S, Reed T. Redox
proteomics in some age-related neurodegenerative disorders
or models thereof. NeuroRx. 2006;3(3):344-57. doi: 10.1016/j.
nurx.2006.05.003
184. Murali G, Panneerselvam C. Age-associated oxidative
macromolecular damages in rat brain regions: role of
glutathione monoester. J Gerontol A Biol Sci Med Sci.
2007;62(8):824-30. doi: 10.1093/gerona/62.8.824
185. Forster MJ, Dubey A, Dawson KM, Stutts WA, Lal H, Sohal
RS. Age-related losses of cognitive function and motor skills
in mice are associated with oxidative protein damage in the
brain. Proc Natl Acad Sci U S A. 1996;93(10):4765-9. doi:
10.1073/pnas.93.10.4765
186. Gorini A, Ghigini B, Villa R. Acetylcholinesterase activity
of synaptic plasma membranes during ageing: effect
of L-acetylcarnitine. Demantia. 1996;7(3):147-54. doi:
10.1159/000106870
187. Geromichalos GD, Lamari FN, Papandreou MA, Trafalis DT,
Margarity M, Papageorgiou A, et al. Saffron as a source of novel
acetylcholinesterase inhibitors: molecular docking and in vitro
enzymatic studies. J Agric Food Chem. 2012;60(24):6131-8.
doi: 10.1021/jf300589c
188. Ochiai T, Ohno S, Soeda S, Tanaka H, Shoyama Y, Shimeno
H. Crocin prevents the death of rat pheochromyctoma (PC-
12) cells by its antioxidant effects stronger than those of
α-tocopherol. Neurosci Lett. 2004;362(1):61-4. doi; 10.1016/j.
neulet.2004.02.067
189. Mehri S, Abnous K, Mousavi SH, Shariaty VM, Hosseinzadeh
H. Neuroprotective effect of crocin on acrylamide-
induced cytotoxicity in PC12 cells. Cell Mol Neurobiol.
2012;32(2):227-35. doi: 0.1007/s10571-011-9752-8
190. Mousavi SH, Tayarani N, Parsaee H. Protective effect of saffron
extract and crocin on reactive oxygen species-mediated high
glucose-induced toxicity in PC12 cells. Cell Mol Neurobiol.
2010;30(2):185-91. doi: 10.1007/s10571-009-9441-z
191. Kannan K, Jain SK. Oxidative stress and apoptosis.
Pathophysiology. 2000;7(3):153-63. doi: 10.1016/s0928-
4680(00)00053-5
192. Scorrano L, Korsmeyer SJ. Mechanisms of cytochrome c
release by proapoptotic BCL-2 family members. Biochem
Biophys Res Commun. 2003;304(3):437-44. doi: 10.1016/
s0006-291x(03)00615-6
193. Zhang G-F, Zhang Y, Zhao G. Crocin protects PC12 cells against
MPP+-induced injury through inhibition of mitochondrial
dysfunction and ER stress. Neurochem Int. 2015;89:101-10.
doi: 10.1016/j.neuint.2015.07.011
194. Nam KN, Park YM, Jung HJ, Lee JY, Min BD, Park SU, et al.
Anti-inflammatory effects of crocin and crocetin in rat brain
microglial cells. Eur J Pharmacol. 2010;648(1-3):110-16. doi:
10.1016/j.ejphar.2010.09.003
195. Hosseinzadeh H, Shakib SS, Sameni AK, Taghiabadi E. Acute
and subacute toxicities of safranal, a constituent of saffron, in
mice and rats. Iran J Pharm Res. 2011;13(44):S122.
196. Hosseinzadeh H, Shariaty VM, Sameni A. Acute and sub-acute
toxicity of crocin, aconstituent of Crocus sativus L.(Saffron), in
mice and rats. January 2010.
197. Mohajeri D, Mousavi G, Mesgari M, Doustar Y, Khayat
Nouri M. Subacute toxicity of Crocus sativus L.(saffron)
stigma ethanolic extract in rats. Am J Pharmacol Toxicol.
2007;2(4):189-93. doi: 10.3844/ajptsp.2207.189.193
198. Khayatnouri M, Safavi SE, Safarmashaei S, Babazadeh
D, Mikailpourardabili B. The effect of saffron orally
administration on spermatogenesis index in rat. Adv Environ
Biol. 2011;5:1514-21.
199. Taheri F, Zahra Bathaie S, Ashrafi M, Ghasemi E. Assessment of
Crocin Toxicity on the Rat Liver. Modares Journal of Medical
Sciences: Pathobiology. 2014;17(3).
200. Riahi-Zanjani B, Balali-Mood M, Mohammadi E, Badie-Bostan
Arch Iran Med, Volume 24, Issue 3, March 2021
252
Zandi et al
H, Memar B, Karimi G. Safranal as a safe compound to mice
immune system. Avicenna J Phytomed. 2015;5(5):441.
201. Muosa F, AL-Rekabi K, Askar S, Yousif E. Evaluation of the
toxic effect of ethanolic extract of saffron in male mice after
subchronic exposure. Donnish J Pharm Pharmacol. 2015;1:1-
7.
202. Bostan HB, Mehri S, Hosseinzadeh H. Toxicology effects of
saffron and its constituents: a review. Iran J Basic Med Sci.
2017;20(2):110. doi: 10.22038/ijbms.2017.8230
203. Khan M, Hanif MA, Ayub MA, Jilani MI, Chatha SAS. Saffron.
Medicinal Plants of South Asia: Elsevier; 2020:587-600.
204. Modaghegh M-H, Shahabian M, Esmaeili HA, Rajbai O,
Hosseinzadeh H. Safety evaluation of saffron (Crocus
sativus) tablets in healthy volunteers. Phytomedicine.
2008;15(12):1032-7. doi: 10.1016/j.phymed.2008.06.003
205. Ayatollahi H, Javan AO, Khajedaluee M, Shahroodian M,
Hosseinzadeh H. Effect of Crocus sativus L.(saffron) on
coagulation and anticoagulation systems in healthy volunteers.
Phytother Res. 2014; 28(4):539-43. doi 10.1002/ptr.5021
206. Mohamadpour AH, Ayati Z, Parizadeh MR, Rajbai O,
Hosseinzadeh H. Safety evaluation of crocin (a constituent
of saffron) tablets in healthy volunteers. Iran J Basic Med Sci.
2013;16(1):39.
207. Ajam M, Reyhani T, Roshanravan V, Zare Z. Increased
miscarriage rate in female farmers working in saffron fields:
a possible effect of saffron toxicity. Asia Pac J Med Toxicol.
2014;3(2):73-5. doi: 10.22038/apjmt.2014.3047
208. Sadraei H, Ghannadi A, Takei-bavani M. Effects of Zataria
multiflora and Carum carvi essential oils and hydroalcoholic
extracts of Passiflora incarnata, Berberis integerrima and
Crocus sativus on rat isolated uterus contractions. International
Journal of Aromatherapy. 2003;13(2-3):121-7. doi: 10.1016/
S0962-4562(03)00092-4
209. Inoue E, Shimizu Y, Shoji M, Tsuchida H, Sano Y, Ito C.
Pharmacological properties of N-095, a drug containing
red ginseng, polygala root, saffron, antelope horn and aloe
wood. Am J Chin Med. 2005; 33(01):49-60. doi 10.1142/
S0192415X05002655.
210. Ahmadi S, Azhari S, Jafarzadeh H, Rakhshandeh H, Mazlom
R. The effect of oral capsules of saffron on anxiety and fatigue
during the first stage of labor. SSU_Journals. 2015;23(2):1915-
26.
211. Ahmadi S, Azhari S, Rakhshandeh H, Jaafarzadeh H, Mazlum
S. Evaluation of the effect of saffron oral capsules on duration
of the active phase of labor first stage. Iran J Reprod Med.
2014;12(6):44.
212. Kamalipour M, Akhondzadeh S. Cardiovascular effects of
saffron: an evidence-based review. Journal of Tehran Heart
Center. 2011 6(2):59-61.
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