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

Effect of Saffron (Crocus sativus) Supplementation on Oxidative Stress, Inflammatory Indices, and Renal and Liver Function Parameters in Patients With Type 2 Diabetes Mellitus: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Clinical Trials

CONTEXT

Clinical investigation has shown that the addition of saffron or crocin to standard antidiabetic medications improves a patient's metabolic profile, oxidative stress (OS), and inflammatory response. Despite a large number of studies examining the impact of saffron supplementation on OS, inflammation, and renal and liver function parameters, no systematic review or meta-analysis has been conducted to compile the outcomes in patients with type 2 diabetes mellitus (T2DM).

OBJECTIVE

The current systematic review and meta-analysis was performed to investigate the effect of saffron or crocin intake on OS, inflammation, and renal and liver function parameters in patients with T2DM.

DATA SOURCES

Online databases including PubMed, Scopus, ISI Web of Science, and Cochrane Library were searched up to December 2023.

DATA EXTRACTION

The mean differences and their respective SDs were extracted. Using a random-effects model, the pooled data were calculated as standardized mean difference (SMD) with 95% CI.

DATA ANALYSIS

17 eligible randomized controlled trials were included in this meta-analysis. The pooled findings showed that saffron supplementation remarkably decreased the levels of tumor necrosis factor-α (SMD: -0.37; 95% CI: -0.69 to -0.05; I2 = 40.77%, P = .15), interleukin-6 (IL-6) (SMD: -0.38; 95% CI: -0.65 to -0.10; I2 = 0%, P = .68), and malondialdehyde (MDA) (SMD: -0.36; 95% CI: -0.65 to -0.07; I2= 20.51%, P = .02) compared with the control. In addition, based on subgroup analyses, taking ≥100 mg of saffron daily in individuals with T2DM reduced the serum levels of IL-6 (SMD: -0.50; 95% CI: -0.90 to -0.10; I2 = 0%, P = .50) and MDA (SMD: -0.36; 95% CI: -0.68 to -0.03; I2 = 0, P = .97). Furthermore, the level of alanine transaminase was decreased (SMD: -0.43; 95% CI: -0.73 to -0.12; I2 = 0, P = .66) with a treatment period of <60 days of saffron or crocin supplementation.

CONCLUSION

Larger studies with more follow-up and higher doses of both saffron and crocin are needed in order to understand the efficacy and safety of these herbs for long-term use as routine therapies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023458119.

Natural remedies proposed for the management of diabetic retinopathy (DR): diabetic complications

Diabetic retinopathy (DR) represents a significant and serious complication associated with diabetes mellitus (DM), often resulting in considerable visual impairment or even blindness. The intricate pathological processes underlying DR complicate the effectiveness of current treatment modalities. Studies have highlighted the potential of natural products in the treatment of DR via several beneficial effects including anti-inflammatory, antioxidant, anti-neovascular, and anti-apoptotic properties. Flavonoids, saponins, saccharides, and alkaloids exhibited various beneficial effects in DR in in vivo and in vitro studies. However, the clinical utilization of these natural compounds is hindered by issues such as inadequate specificity, low bioavailability, and potential toxicity. Therefore, there is a pressing need for rigorous clinical studies to confirm the efficacy of natural products in preventing or mitigating the progression of DR.

Nrf-2-dependent antioxidant and anti-inflammatory effects underlie the protective effect of esculeoside A against retinal damage in streptozotocin-induced diabetic rats

Esculeoside A (ESA) is a tomato-derived glycoside with antioxidant and anti-inflammatory properties. The protective effect of ESA against diabetic retinopathy is not well-investigated and was the core objective of this study. In addition, we tested if such protection involves the activation of Nrf2 signaling. Type 1 diabetes mellitus (T1DM) was induced in adult Wistar male rats by an intraperitoneal injection of streptozotocin (65 mg/kg). Non-diabetic and T1DM rats were divided into two subgroup groups given either the vehicle or ESA (100 mg)/kg. An additional T1DM group was given ESA (100 mg/kg) and an Nrf2 inhibitor (2 mg/kg) (n=8 rats/group). Treatments continued for 12 weeks. In this study, according to the histological features, ESA improved the structure of ganglionic cells and increased the number of cells of the inner nuclear and plexiform layers in the retinas of T1DM rats. Concomitantly, it reduced the retina levels of malondialdehyde (lipid peroxides), vascular endothelial growth factor, interleukin-6, tumor necrosis factor-α, Bax, and caspase-3. In the retinas of the control and diabetic rats, ESA boosted the levels of total glutathione, superoxide dismutase, heme-oxygenase-1, and Bcl2, reduced the mRNA levels of REDD1, and enhanced cytoplasmic and nuclear levels of Nrf2. However, ESA failed to alter the mRNA levels of Nrf2 and keap1, protein levels of keap1, plasma glucose, plasma insulin, serum triglycerides, cholesterol, and LDL-c in both the control and T1DM rats. In conclusion, ESA alleviates retinopathy in T1DM rats by suppressing REDD1-associated degradation and inhibiting the Nrf2/antioxidant axis.

Natural inhibitors for acetylcholinesterase and autophagy modulators as effective antagonists for tau and β-amyloid in Alzheimer's rat model

Background: Phytochemicals have amazing biological effects in relation to age-related illnesses and are increasingly being studied in clinical trials. The goal of this study was to examine the effectiveness of the aqueous extracts of Rosmarinus officinalis L. (Rosemary) and Crocus sativus L. (Saffron) and their combinations as tau and β-amyloid antagonists in an Alzheimer's rat model. Methods: AlCl₃ and D-galactose (150 & 300 mg/kg) were used to create the Alzheimer's neuroinflammation rat model. The animals were subsequently given the two extracts and their combinations (500 mg/kg) along 15 days. The cognitive impairment, oxidative stress, tau & amyloid neuroproteins, acetylcholine, acetylcholinesterase neurotransmitters, proinflammatory cytokines, LC3 as an autophagy marker, computational analysis, and morphological alterations were all assessed. Results: When compared to the conventional donepezil and normal groups, the treated groups showed a significant improvement in all calculated parameters. The cortex and hippocampus have a better morphological appearance. In silico analysis found that these extracts may have an affinity for and impede the activity of some proteins thought to be essential regulators of disease progression. Conclusion: Rosemary and Saffron extracts by the power of their constituents were able to alleviate the neurotoxicity of AlCl₃ & D-galactose and regulate the natural autophagy process.

Saffron as a promising therapy for diabetes and Alzheimer's disease: mechanistic insights

The prevalence of both Alzheimer's disease (AD) and diabetes mellitus is increasing with the societies' aging and has become an essential social concern worldwide. Accumulation of amyloid plaques and neurofibrillary tangles (NFTs) of tau proteins in the brain are hallmarks of AD. Diabetes is an underlying risk factor for AD. Insulin resistance has been proposed to be involved in amyloid-beta (Aβ) aggregation in the brain. It seems that diabetic conditions can result in AD pathology by setting off a cascade of processes, including inflammation, mitochondrial dysfunction, and ROS and advanced glycation end products (AGEs) synthesis. Due to the several side effects of chemical drugs and their high cost, using herbal medicine has recently attracted attention for the treatment of diabetes and AD. Saffron and its active ingredients have been used for its anti-inflammatory, anti-oxidant, anti-diabetic, and anti-AD properties. Therefore, in the present review paper, we take account of the clinical, in vivo and in vitro evidence regarding the anti-diabetic and anti-AD effects of saffron and discuss the preventive or postponing properties of saffron or its components on AD development via its anti-diabetic effects.

Saffron (Crocus sativus L.): A Source of Nutrients for Health and for the Treatment of Neuropsychiatric and Age-Related Diseases

Saffron (Crocus sativus L.) is a medicinal plant, originally cultivated in the East and Middle East, and later in some Mediterranean countries. Saffron is obtained from the stigmas of the plant. Currently, the use of saffron is undergoing a revival. The medicinal virtues of saffron, its culinary use and its high added value have led to the clarification of its phytochemical profile and its biological and therapeutic characteristics. Saffron is rich in carotenoids and terpenes. The major products of saffron are crocins and crocetin (carotenoids) deriving from zeaxanthin, pirocrocin and safranal, which give it its taste and aroma, respectively. Saffron and its major compounds have powerful antioxidant and anti-inflammatory properties in vitro and in vivo. Anti-tumor properties have also been described. The goal of this review is to present the beneficial effects of saffron and its main constituent molecules on neuropsychiatric diseases (depression, anxiety and schizophrenia) as well as on the most frequent age-related diseases (cardiovascular, ocular and neurodegenerative diseases, as well as sarcopenia). Overall, the phytochemical profile of saffron confers many beneficial virtues on human health and, in particular, on the prevention of age-related diseases, which is a major asset reinforcing the interest for this medicinal plant.

Nutraceutical Supplementation Ameliorates Visual Function, Retinal Degeneration, and Redox Status in rd10 Mice

Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by progressive degeneration of photoreceptor cells. Ocular redox status is altered in RP suggesting oxidative stress could contribute to their progression. In this study, we investigated the effect of a mixture of nutraceuticals with antioxidant properties (NUT) on retinal degeneration in rd10 mice, a model of RP. NUT was orally administered to rd10 mice from postnatal day (PD) 9 to PD18. At PD18 retinal function and morphology were examined by electroretinography (ERG) and histology including TUNEL assay, immunolabeling of microglia, Müller cells, and poly ADP ribose polymers. Retinal redox status was determined by measuring the activity of antioxidant enzymes and some oxidative stress markers. Gene expression of the cytokines IL-6, TNFα, and IL-1β was assessed by real-time PCR. NUT treatment delayed the loss of photoreceptors in rd10 mice partially preserving their electrical responses to light stimuli. Moreover, it ameliorated redox status and reduced inflammation including microglia activation, upregulation of cytokines, reactive gliosis, and PARP overactivation. NUT ameliorated retinal functionality and morphology at early stages of RP in rd10 mice. This formulation could be useful as a neuroprotective approach for patients with RP in the future.