Didymin protects against polystyrene nanoplastic-induced hepatic damage in male albino rats by modulation of Nrf-2/Keap-1 pathway

Polystyrene nanoplastics (PS-NPs) are ubiquitous environmental pollutants that can cause oxidative stress in various organs, including the liver. Didymin is a dietary flavanone that displays multiple pharmacological activities. Therefore, the present study evaluated the palliative role of didymin against PS-NPs-induced hepatic damage in rats. Albino rats (n=48) were randomly distributed into 4 groups: control, PS-NPs treated group, PS-NPs + didymin co-administered group, and didymin supplemented group. After 30 days, PS-NPs intoxication lowered the expression of Nrf-2 and anti-oxidant genes [catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR), glutathione-S-transferase (GST), and heme oxygenase-1 (HO-1)], whereas the expression of KEAP1 kelch like ECH associated protein 1 (Keap-1) was increased. PS-NPs exposure also reduced the activities of anti-oxidants enzymes (CAT, SOD, GPx, GSR, GST, GSH, and OH-1), while malondialdehyde (MDA) and reactive oxygen species (ROS) levels were increased. The levels of alanine transaminase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were increased in PS-NPs-exposed rats. Moreover, inflammatory indices [interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB), and cyclooxygenase-2 (COX-2)] were increased in PS-NPs-exposed rats. Furthermore, PS-NPs intoxication increased the expressions of apoptotic markers including Bax and Caspase-3, as well as reducing Bcl-2 expression. The histopathological analysis showed significant damage in PS-NPs-treated rats. However, didymin supplementation ameliorated all the PS-NPs-induced damage in the liver of rats. Therefore, it was concluded that didymin can act as a remedy against PS-NPs-induced liver toxicity due to its anti-apoptotic, anti-oxidant, and anti-inflammatory activities.

Didymin Alleviates Cerebral Ischemia-Reperfusion Injury by Activating the PPAR Signaling Pathway

PURPOSE

Cerebral ischemia-reperfusion (IR) injury is a severe secondary injury induced by reperfusion after stroke. Didymin has been reported to have a protective effect on intracerebral hemorrhage. However, the underlying mechanism of didymin on regulating cerebral IR injury remains largely unknown.

MATERIALS AND METHODS

A rat cerebral IR model and oxygen-glucose deprivation/reperfusion (OGD/R) model in PC12 cells were established. Hematoxylin and eosin (H&E) was used to detect the pathological changes in brain tissues, and TUNEL staining was performed to detect apoptosis of brain tissues. MTT and flow cytometry were used to measure the viability and apoptosis of PC12 cells. QRT-PCR and western blot were used to detect inflammation cytokines in PC12 cells. Western blot was used to measure the expression of PPAR-γ, RXRA, Bax, c-caspase-3, and Bcl-2.

RESULTS

Didymin pretreatment decreased apoptotic rates, reduced levels of Bax and c-caspase-3, and increased Bcl-2 level in vivo and in vitro. Additionally, didymin pretreatment increased viability and decreased the inflammation levels [interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and monocyte chemotactic protein (MCP)-1] of OGD/R treated PC12 cells. Moreover, didymin activated the peroxisome proliferator-activated receptors (PPAR) signaling pathway and increased the expression of PPAR-γ and RXRA in OGD/R treated PC12 cells. Inhibition of PPAR-γ eliminated the protective effect of didymin on OGD/R treated cells.

CONCLUSION

Didymin protected neuron cells against IR injury in vitro and in vivo by activation of the PPAR pathway. Didymin may be a candidate drug for IR treatment.

Didymin Ameliorates Liver Fibrosis by Alleviating Endoplasmic Reticulum Stress and Glycerophospholipid Metabolism: Based on Transcriptomics and Metabolomics

Introduction

Origanum vulgare L. is a traditional Chinese herb, having a strong hepatoprotective effect. In our previous experiments, we have isolated an ingredient from this herb and identified it as didymin. This study aimed to investigate the effects and underlying mechanisms of didymin on liver injury and fibrosis, elucidating whether it was the pharmacodynamic material basis of Origanum vulgare L.

Methods

Mice were injected with CCl₄ for 10 weeks to induce liver fibrosis, followed by didymin treatment for 6 weeks. Then, biochemical analysis and histopathological examinations were conducted to evaluate the therapeutic effects of didymin in alleviating fibrosis. Next, the possible mechanisms of didymin were predicted by transcriptomics and then verified by the multiple relevant examinations.

Results

The pharmacodynamic experiments indicated that didymin significantly attenuated CCl₄-induced hepatic injury and fibrogenesis, as evidenced by the ameliorative pathological tissue, low transaminase activity, and decreased collagen accumulation. Interestingly, the transcriptome analysis predicted that the potential targets were likely to be endoplasmic reticulum stress (ERS), inflammation, apoptosis, and metabolic pathways. And the predictions were then verified by the following examinations: (1) didymin significantly inhibited ERS by regulating the ATF6, IRE1α, and PERK pathways; (2) didymin markedly alleviated hepatocyte apoptosis by restoring the expression of Bcl-2 and caspase families, as well as the mitochondrial dysfunction; (3) didymin significantly decreased the production of the pro-inflammatory cytokines (IL-1β and IL-6); (4) didymin inhibited the glycerophospholipid metabolism pathway by decreasing the synthesis of phosphatidylethanolamines and phosphatidylcholines.

Conclusion

Our findings demonstrate that didymin can ameliorate liver fibrosis, which is mainly attributed to the inhibition of ERS, inflammation, and glycerophospholipid metabolism.

Recent Trends in Potential Therapeutic Applications of the Dietary Flavonoid Didymin

Didymin (isosakuranetin 7-O-rutinoside) is an orally bioactive dietary flavonoid glycoside first found in citrus fruits. Traditionally, this flavonoid has long been used in Asian countries as a dietary antioxidant. Recent studies have provided newer insights into this pleiotropic compound, which could regulate multiple biological activities of many important signaling molecules in health and disease. Emerging data also presented the potential therapeutic application of dietary flavonoid glycoside didymin against cancer, neurological diseases, liver diseases, cardiovascular diseases, and other diseases. In this review, we briefly introduce the source and extraction methods of didymin, and summarize its potential therapeutic application in the treatment of various diseases, with an emphasis on molecular targets and mechanism that contributes to the observed therapeutic effects. The dietary flavonoid didymin can be used to affect health and disease with multiple therapeutic targets, and it is anticipated that this review will stimulate the future development of this potential dietary medicine.

[Study on difference of flavonoids content in stems and leaves of Mentha Haplocalycis Herba in different harvest periods]

The dynamic changes of active components in stems and leaves of Mentha Haplocalycis Herba(mint) at different harvest periods were investigated, and the optimum harvest time of mint was explored. In this study, hesperidin, diosmin, didymin and buddleoside were selected as flavonoids index components of mint, and the QAMS method was established to measure the contents of these flavonoids in mint. The contents of 4 flavonoid glycosides in the mint stems and leaves from three habitats harvested in different time were studied and evaluated comprehensively using statistical analysis and principal component analysis (PCA). The results showed that the contents of 4 components in the leaves are higher than that in the stems despite of habitats and harvest time, and they all exhibited dynamic changes along with the harvest periods within the same habitat. Three harvest periods in mid April, mid September and late October scored higher in comprehensive evaluation in Jiangsu region, the genuine producing area of Mentha Haplocalycis Herba. Combined with the yield and contents of active compounds, the optimum harvest time of mint in Jiangsu region was mid September and late October, which is basically consistent with the traditional harvesting periods.

Didymin: an orally active citrus flavonoid for targeting neuroblastoma

Neuroblastoma, a rapidly growing yet treatment responsive cancer, is the third most common cancer of children and the most common solid tumor in infants. Unfortunately, neuroblastoma that has lost p53 function often has a highly treatment-resistant phenotype leading to tragic outcomes. In the context of neuroblastoma, the functions of p53 and MYCN (which is amplified in ~25% of neuroblastomas) are integrally linked because they are mutually transcriptionally regulated, and because they together regulate the catalytic activity of RNA polymerases. Didymin is a citrus-derived natural compound that kills p53 wild-type as well as drug-resistant p53-mutant neuroblastoma cells in culture. In addition, orally administered didymin causes regression of neuroblastoma xenografts in mouse models, without toxicity to non-malignant cells, neural tissues, or neural stem cells. RKIP is a Raf-inhibitory protein that regulates MYCN activation, is transcriptionally upregulated by didymin, and appears to play a key role in the anti-neuroblastoma actions of didymin. In this review, we discuss how didymin overcomes drug-resistance in p53-mutant neuroblastoma through RKIP-mediated inhibition of MYCN and its effects on GRK2, PKCs, Let-7 micro-RNA, and clathrin-dependent endocytosis by Raf-dependent and -independent mechanisms. In addition, we will discuss studies supporting potential clinical impact and translation of didymin as a low cost, safe, and effective oral agent that could change the current treatment paradigm for refractory neuroblastoma.

Didymin reverses phthalate ester-associated breast cancer aggravation in the breast cancer tumor microenvironment

The present study demonstrated two novel findings. To the best of our knowledge, it is the first study to demonstrate that regulated upon activation, normal T-cell expressed and secreted (RANTES), produced by breast tumor-associated monocyte-derived dendritic cells (TADCs) following breast cancer cell exposure to phthalate esters, may contribute to the progression of cancer via enhancement of cancer cell proliferation, migration and invasion. Furthermore, the present study revealed that didymin, a dietary flavonoid glycoside present in citrus fruits, was able to reverse phthalate ester-mediated breast cancer aggravation. MDA-MB-231 cells were treated with butyl benzyl phthalate (BBP), di-n-butyl phthalate (DBP) or di-2-ethylhexyl phthalate (DEHP). Subsequently, the conditioned medium (CM) was harvested and cultured with monocyte-derived dendritic cells (mdDCs). Cultures of MDA-MB-231 cells with the conditioned medium of BBP-, DBP- or DEHP-MDA-MB-231 tumor-associated mdDCs (BBP-, DBP- or DEHP-MDA-TADC-CM) demonstrated enhanced proliferation, migration and invasion. Exposure of the MDA-MB-231 cells to DBP induced the MDA-TADCs to produce the inflammatory cytokine RANTES, which subsequently induced MDA-MB-231 cell proliferation, migration and invasion. Depleting RANTES reversed the effects of DBP-MDA-TADC-mediated MDA-MB-231 cell proliferation, migration and invasion. In addition, didymin was observed to suppress phthalate-mediated breast cancer cell proliferation, migration and invasion. The present study suggested that didymin was capable of preventing phthalate ester-associated cancer aggravation.