Crocetin Exerts Its Anti-inflammatory Property in LPS-Induced RAW264.7 Cells Potentially via Modulation on the Crosstalk between MEK1/JNK/NF-κB/iNOS Pathway and Nrf2/HO-1 Pathway

Metabolic engineering of Yarrowia lipolytica for the production and secretion of the saffron ingredient crocetin

BACKGROUND

Crocetin is a multifunctional apocarotenoid natural product derived from saffron, holding significant promises for protection against various diseases and other nutritional applications. Historically, crocetin has been extracted from saffron stigmas, but this method is hindered by the limited availability of high-quality raw materials and complex extraction processes. To overcome these challenges, metabolic engineering and synthetic biology can be applied to the sustainable production of crocetin.

RESULTS

We constructed a Yarrowia lipolytica strain using hybrid promoters and copy number adjustment, which was able to produce 2.66 g/L of β-carotene, the precursor of crocetin. Next, the crocetin biosynthetic pathway was introduced, and we observed both the production and secretion of crocetin. Subsequently, the metabolite profiles under varied temperatures were studied and we found that low temperature was favorable for crocetin biosynthesis in Y. lipolytica. Therefore, a two-step temperature-shift fermentation strategy was adopted to optimize yeast growth and biosynthetic enzyme activity, bringing a 2.3-fold increase in crocetin titer. Lastly, fermentation media was fine-tuned for an optimal crocetin output of 30.17 mg/L, bringing a 51% higher titer compared with the previous highest report in shake flasks. Concomitantly, we also generated Y. lipolytica strains capable of achieving substantial zeaxanthin production, yielding 1575.09 mg/L, doubling the previous highest reported titer.

CONCLUSIONS

Through metabolic engineering and fermentation optimization, we demonstrated the first de novo biosynthesis of crocetin in the industrial yeast Yarrowia lipolytica. In addition, we achieved a higher crocetin titer in flasks than all our known reports. This work not only represents a high production of crocetin, but also entails a significant simultaneous zeaxanthin production, setting the stage for sustainable and cost-effective production of these valuable compounds.

Phytochemicals in the treatment of patients with depression: a systemic review

Background

Depression is a complex mental disease whose incidence increases every year; 300 million people worldwide currently suffer from it. Women are more likely to suffer from depression, twice the rate as men. It is one of the few illnesses that can lead to suicide, which makes it very dangerous - currently, 700,000 people die from suicide and it is the 4th most common cause of death in people aged 15-29. The treatment strategies for depression is a big challenge for physicians, pharmacists, scientists and classic remedies cause many side effects. Therefore, natural phytotherapy with herbs can prove to be a good solution. Phytotherapy is a popular treatment method used for centuries in Chinese medicine or Ayurveda.

Materials and methods

The study conducted a comprehensive database search PubMed, ClinicalKey and MedNar covered the years 2015 - 2024 to provide the most up-to-date data. 13 randomized controlled trials and 1 meta - analysis were included in the systematic review.

Results

Many plants show anti-inflammatory, antioxidant and cognitive enhancing effects, which are particularly important in depression. In the treatment of depression, plants such as Crocus sativus L. stigma, Lavandula angustifolia, Hypericum perforatum L. and Curcuma longa L. have proven to be effective. They show good effectiveness in human studies and alleviate the symptoms of depression. Herbal products can support classical pharmacotherapy, but this requires further research. Non-commercial clinical trials in the future should provide answers to research questions: at what stage of treatment of patients with MDD will the use of phytochemicals be most appropriate in terms of therapy efficacy and safety for the patient.

Conclusions

Crocus sativus L. stigma, Lavandula angustifolia, Hypericum perforatum L. and Curcuma longa L. in modern medicine can help improve the well-being of patients with depression. The use of herbs as an intervention was associated with a decrease in the concentration of proinflammatory cytokines and an overall improvement in the mood of patients. Further research should be undertaken into combining both therapies in order to improve patients' quality of life and reduce treatment costs.

Saffron as a Promising Therapy for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory illness of the gastrointestinal tract (GI), characterized by recurrent episodes of inflammation and tissue destruction. It affects an increasing number of individuals worldwide who suffer from Crohn's disease (CD) or ulcerative colitis (UC). Despite substantial advances in understanding the underlying causes of IBD, the available treatments remain restricted and are sometimes accompanied by severe consequences. Consequently, there is an urgent need to study alternate therapeutic options. This review assesses the present drugs, identifies their limitations, and proposes the use of saffron, a natural plant with great therapeutic potential based on preclinical and clinical investigations. Saffron has gained attention for its potential therapeutic benefits in treating various ailments due to its established bioactive compounds possessing antioxidant and anti-inflammatory properties. This review covers how saffron impacts the levels of calprotectin, an inflammatory marker, for various inflammatory responses in multiple diseases including IBD. Data from clinical trials were assessed to determine the efficacy and safety of using saffron to counter inflammation in multiple diseases. Studies have shown that saffron may protect against inflammatory bowel disease (IBD) through several mechanisms by inhibiting pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), reducing oxidative stress through antioxidant effects, enhancing mucosal barrier function by upregulating tight junction proteins, and modulating the gut microbiota composition to promote beneficial bacteria while suppressing pathogenic ones; these combined actions contribute to its therapeutic potential in managing and alleviating the symptoms of IBD. This will enable future research endeavors and expedite the translation of saffron-based interventions into clinical practice as a valuable adjunctive therapy or a potential alternative to conventional treatments, thereby enhancing the quality of life for individuals suffering from inflammatory diseases including IBD.

Proanthocyanidins isolated from lotus seed skin mitigate glycolipid metabolism disorder through the p38/Nrf2/NF-κB signaling pathway

Lotus seed skin extract is rich in flavonoids, making it a promising candidate for developing health products. In a previous study, we found that proanthocyanidins from lotus seed skin, particularly proanthocyanidin B1 (PB1), can indirectly activate the Nrf2 signaling pathway, exerting an antioxidant effect. In this study, we isolate proanthocyanidins from lotus seed skin (PLS) using ethanol extraction and RP-HPLC identification, and investigate its effects on glycolipid metabolism both in vivo and in vitro. Our results demonstrate that PLS reduces body weight in high-fat diet (HFD) mice by decreasing feed efficiency. PLS also normalizes serum glucose, insulin secretion, glycosylated hemoglobin (HbA1c), and intraperitoneal glucose tolerance (IPGTT). Furthermore, PLS significantly improves blood lipid parameters and inhibits the expressions of six proinflammatory factors, including IL-1α, IL-1β, IL-3, IL-6, IFN-γ and TNF-α in HFD mice. Additionally, analysis of fresh liver tissues reveals that PLS and PB1 induce the expressions of antioxidant proteins such as HO-1 and NQO1 by activating the p38-Nrf2 signaling pathway and inhibiting the NF-κB signaling pathway. In conclusion, proanthocyanidins from lotus seed skin regulate glycolipid metabolism disorders by targeting the p38/Nrf2/NF-κB signaling pathway. Our study offers a new approach for the high-value comprehensive utilization of lotus seed skin by-products and precise dietary intervention for metabolic syndrome.

Crocetin inhibits choroidal neovascularization in both in vitro and in vivo models

Choroidal neovascularization (CNV) is the primary pathogenic process underlying wet age-related macular degeneration, leading to severe vision loss. Despite current anti-vascular endothelial growth factor (VEGF) therapies, several limitations persist. Crocetin, a major bioactive constituent of saffron, exhibits multiple pharmacological activities, yet its role and mechanism in CNV remain unclear. Here, we investigated the potential effects of crocetin on CNV using in vitro and in vivo models. In human umbilical vein endothelial cells, crocetin demonstrated inhibition of VEGF-induced cell proliferation, migration, and tube formation in vitro, as assessed by CCK-8 and EdU assays, transwell and scratch assays, and tube formation analysis. Additionally, crocetin suppressed choroidal sprouting in ex vivo experiments. In the human retinal pigment epithelium (RPE) cell line ARPE-19, crocetin attenuated cobalt chloride-induced hypoxic cell injury, as evidenced by CCK-8 assay. As evaluated by quantitative PCR and Western blot assay, it also reduced hypoxia-induced expression of VEGF and hypoxia-inducible factor 1α (HIF-1α), while enhancing zonula occludens-1 expression. In a laser-induced CNV mouse model, intravitreal administration of crocetin significantly reduced CNV size and suppressed elevated expressions of VEGF, HIF-1α, TNFα, IL-1β, and IL-6. Moreover, crocetin treatment attenuated the elevation of phospho-S6 in laser-induced CNV and hypoxia-induced RPE cells, suggesting its potential anti-angiogenic effects through antagonizing the mechanistic target of rapamycin complex 1 (mTORC1) signaling. Our findings indicate that crocetin may hold promise as an effective drug for the prevention and treatment of CNV.

Crocetin regulates Th1/Th2 and Th17/Treg balances, nitric oxide production, and nuclear localization of NF-κB in Th2-provoked and normal situations in human-isolated lymphocytes

Crocetin is a natural carotenoid dicarboxylic acid derived from Crocus sativus. It has been utilized as natural biomedicine with healing effects. The immunoregulatory and anti-inflammatory properties may cause the biological activities of crocetin. Nevertheless, it is not still clear how this compound acts and causes an immune-modulatory impact on human lymphocytes. The effects of three concentrations (5, 10, and 20 μM) of crocetin or dexamethasone (0.1 mM) were assessed on gene expression and secretion of cytokines, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) level, and nitric oxide (NO) production in phytohaemagglutinin (PHA)-stimulated and non-stimulated lymphocytes. By incubation with PHA, gene expression and cytokine concentration comprising interferon (IFN)-γ, interleukin (IL)-17A, IL-10, and IL-4 were increased, along with NF-κB concentration and NO production (all, p < 0.001). In comparison with the controls, an alteration occurred in the T-helper (Th)2/Th1 and Th17/Treg balance in the stimulated lymphocyte toward a Th2 and Th17 response. In stimulated cells, crocetin and dexamethasone decreased pro-inflammatory significantly and increased anti-inflammatory cytokines and related gene expression, respectively. Moreover, Th17/Treg and Th1/Th2 balance was changed toward Treg and Th1 significantly reducing NF-κB and NO levels (p < 0.05 to p < 0.001). Promoting effects were represented by crocetin on T-cell subsets to Treg and Th1. Hence, it can have therapeutic value for treating predominant diseases of Th2 or Th17 cells.

Crocetin confers neuroprotection and is anti-inflammatory in rats with induced glaucoma

BACKGROUND

Crocetin is a bioactive ingredient in saffron, derived from the Crocus sativus stigmas of the Iridaceae family. As a chemically carotenoid derivative, crocetin exhibites effects like anti-inflammatory, antioxidant, neuroprotective, etc. However, the protective effect of crocetin on glaucoma and its mechanism remains unclear. The current study assesed the neuroprotective and anti-inflammatory effects of crocetin on retinal neurons in glaucoma rats which were induced by 0.3% carbomer injection into the anterior chamber.

METHODS AND RESULTS

The pathological structures on the retina and optic nerve were observed and examined by H&E staining and transmission electron microscopy. Immunohistochemical staining was used to detect the expression of TNF-α, IL-1β, and IL-6 of the retina and the expression of a brain-derived neurotrophic factor (BDNF) in the primary visual cortex (PVC). Western blot was carried out to detect the expression of PI3K, Akt, and NF-κB in the retina. It was found that crocetin ameliorated the pathological changes of the retina and ON and reduced the number of apoptotic retinal ganglion cells. Immunohistochemical staining showed that crocetin could decrease the contents of TNF-α, IL-1β, and IL-6 and increase the contents of BDNF. Western blot showed that crocetin was found to suppress the expression of PI3K, Akt, and NF-κB.

CONCLUSION

The results obtained in this study have indicated that crocetin showes neuroprotective effects on retinal ganglion cells in glaucoma rats and inhibits retinal dysfunction. Meanwhile, crocetin exerted an anti-inflammatory effect to protect the retina by inhibiting the expression of the PI3K/Akt/NF-κB signaling pathway. This work provides substantial evidence that crocetin may be a potential drug for the treatment of glaucoma.

Safety Assessment and Pain Relief Properties of Saffron from Taliouine Region (Morocco)

Saffron is the most expensive spice in the world. In addition to its culinary utilization, this spice is used for medicinal purposes such as in pain management. In this study, the analgesic activity of Crocus sativus stigma extract (CSSE) was evaluated in rodents and its possible physiological mechanism was elucidated. The anti-nociceptive effect of CSSE was evaluated using three animal models (hot plate, writhing, and formalin tests). The analgesic pathways involved were assessed using various analgesia-mediating receptors antagonists. The oral administration of CSSE, up to 2000 mg/kg, caused no death or changes in the behavior or in the hematological and biochemical blood parameters of treated animals nor in the histological architecture of the animals’ livers and kidneys. CSSE showed a central, dose-dependent, anti-nociceptive effect in response to thermal stimuli; and a peripheral analgesic effect in the test of contortions induced by acetic acid. The dual (central and peripheral) analgesic effect was confirmed by the formalin test. The anti-nociceptive activity of CSSE was totally or partially reversed by the co-administration of receptor antagonists, naloxone, atropine, haloperidol, yohimbine, and glibenclamide. CSSE influenced signal processing, by the modulation of the opioidergic, adrenergic, and muscarinic systems at the peripheral and central levels; and by regulation of the dopaminergic system and control of the opening of the ATP-sensitive K⁺ channels at the spinal level. The obtained data point to a multimodal mechanism of action for CSSE: An anti-inflammatory effect and a modulation, through different physiological pathways, of the electrical signal generated by the nociceptors. Further clinical trials are required to endorse the potential utilization of Moroccan saffron as a natural painkiller.

Crocetin: A Systematic Review

Crocetin is an aglycone of crocin naturally occurring in saffron and produced in biological systems by hydrolysis of crocin as a bioactive metabolite. It is known to exist in several medicinal plants, the desiccative ripe fruit of the cape jasmine belonging to the Rubiaceae family, and stigmas of the saffron plant of the Iridaceae family. According to modern pharmacological investigations, crocetin possesses cardioprotective, hepatoprotective, neuroprotective, antidepressant, antiviral, anticancer, atherosclerotic, antidiabetic, and memory-enhancing properties. Although poor bioavailability hinders therapeutic applications, derivatization and formulation preparation technologies have broadened the application prospects for crocetin. To promote the research and development of crocetin, we summarized the distribution, preparation and production, total synthesis and derivatization technology, pharmacological activity, pharmacokinetics, drug safety, drug formulations, and preparation of crocetin.