Rhamnazin attenuates inflammation and inhibits alkali burn-induced corneal neovascularization in rats

Flavonoids with Anti-Angiogenesis Function in Cancer

The formation of new blood vessels, known as angiogenesis, significantly impacts the development of multiple types of cancer. Consequently, researchers have focused on targeting this process to prevent and treat numerous disorders. However, most existing anti-angiogenic treatments rely on synthetic compounds and humanized monoclonal antibodies, often expensive or toxic, restricting patient access to these therapies. Hence, the pursuit of discovering new, affordable, less toxic, and efficient anti-angiogenic compounds is imperative. Numerous studies propose that natural plant-derived products exhibit these sought-after characteristics. The objective of this review is to delve into the anti-angiogenic properties exhibited by naturally derived flavonoids from plants, along with their underlying molecular mechanisms of action. Additionally, we summarize the structure, classification, and the relationship between flavonoids with their signaling pathways in plants as anti-angiogenic agents, including main HIF-1α/VEGF/VEGFR2/PI3K/AKT, Wnt/β-catenin, JNK1/STAT3, and MAPK/AP-1 pathways. Nonetheless, further research and innovative approaches are required to enhance their bioavailability for clinical application.

Combined administration of gallic acid and glibenclamide mitigate systemic complication and histological changes in the cornea of diabetic rats induced with streptozotocin

PURPOSE

To determine the effect of gallic acid or its combination with glibenclamide on some biochemical markers and histology of the cornea of streptozotocin (STZ) induced diabetic rats.

METHODS

Following induction of diabetes, 24 male albino rats were divided into four groups of six rats each. Groups 1 and 2 (control and diabetic) received rat pellets and distilled water; group 3 (gallic acid) received rat pellets and gallic acid (10 mg/kg, orally) dissolved in the distilled water; and group 4 (gallic acid + glibenclamide) received rat pellets, gallic acid (10 mg/kg, orally), and glibenclamide (5 mg/kg, orally) dissolved in the distilled water. The treatments were administered for three months after which the rats were sacrificed after an overnight fast. Blood and sera were collected for the determination of biochemical parameters, while their eyes were excised for histology.

RESULTS

STZ administration to the rats induced insulin resistance, hyperglycemia, microprotenuria, loss of weight, oxidative stress, inflammation, and alteration of their cornea histology, which was abolished following supplementation with gallic acid or its combination with glibenclamide.

CONCLUSIONS

The study showed the potentials of gallic acid and glibenclamide in mitigating systemic complication and histological changes in the cornea of diabetic rats induced with STZ.

The role of the JAK/STAT3 signaling pathway in acquired corneal diseases

Acquired corneal diseases such as dry eye disease (DED), keratitis and corneal alkali burns are significant contributors to vision impairment worldwide, and more effective and innovative therapies are urgently needed. The Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway plays an indispensable role in cell metabolism, inflammation and the immune response. Studies have shown that regulators of this pathway are extensively expressed in the cornea, inducing significant activation of JAK/STAT3 signaling in specific acquired corneal diseases. The activation of JAK/STAT3 signaling contributes to various pathophysiological processes in the cornea, including inflammation, neovascularization, fibrosis, and wound healing. In the context of DED, the hypertonic environment activates JAK/STAT3 signaling to stimulate corneal inflammation. Inflammation and injury progression in infectious keratitis can also be modulated by JAK/STAT3 signaling. Furthermore, JAK/STAT3 signaling is involved in every stage of corneal repair after alkali burns, including acute inflammation, angiogenesis and fibrosis. Treatments modulating JAK/STAT3 signaling have shown promising results in attenuating corneal damage, indicating its potential as a novel therapeutic target. Thus, this review emphasizes the multiple roles of the JAK/STAT3 signaling pathway in common acquired corneal disorders and summarizes the current achievements of JAK/STAT3-targeting therapy to provide new insights into future applications.

Rhamnazin ameliorates 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin-evoked testicular toxicity by restoring biochemical, spermatogenic and histological profile in male albino rats

2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is a potential environmental toxin that has the ability to affect male reproductive tract. Rhamnazin is a naturally present flavone that displays multiple medicinal properties. Therefore, the current study was designed to determine the mitigative role of rhamnazin against TCDD induced reproductive damage. 48 adult male albino rats were randomly separated into four groups: control, TCDD (10 µgkg-1), TCDD + rhamnazin (10 µgkg-1 + 5 mgkg-1 respectively) and rhamnazin (5 mgkg-1). The trial was conducted for 56 days. TCDD intoxication notably affected superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR) and catalase (CAT) activities, besides reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations were augmented. TCDD administration also lowered sperm motility, viability, sperm number, while it augmented the sperm morphological (tail, neck/midpiece and head) anomalies. Moreover, it decreased the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and plasma testosterone. Moreover, TCDD reduced steroidogenic enzymes i.e., 17-beta hydroxysteroid dehydrogenase (17β-HSD), steroidogenic acute regulatory protein (StAR) and 3-beta hydroxysteroid dehydrogenase (3β-HSD) as well as B-cell lymphoma 2 (Bcl-2) expressions, but increased the expressions of Bcl-2-associated X protein (Bax) and cysteine-aspartic acid protease (Caspase-3). Furthermore, TCDD exposure also induced histopathological anomalies in testicular tissues. However, the supplementation of rhamnazin recovered all the mentioned damages in the testicles. The outcomes revealed that rhamnazin can ameliorate TCDD induced reproductive toxicity due to its anti-oxidant, anti-apoptotic and androgenic nature.

Phytochemical Profile and Antioxidant Capacity of Viscum album L. Subsp. album and Effects on Its Host Trees

Viscum album L. subsp. album is a hemiparasitic plant that is recognized as a medicinal plant due to its beneficial effects, including anti-tumor activity, antioxidant, anti-inflammatory, anti-hepatotoxic, hypoglycemic, and antimicrobial properties as well as for lowering blood pressure. On the other hand, mistletoe is a biotic stressor for both deciduous trees and conifers. Our main aim was to evidence the influence of mistletoe on the content of chlorophylls, proline, total phenols, flavonoids, and antioxidant capacity of leaves from tree host trees (Malus domestica, Prunus domestica, and Populus alba) that grow on the northwest of Romania. In addition, HPLC-DAD-MS-ESI+ was used to analyze the phenolic acid and flavonoid profiles of V. album L. subsp. album leaves according to their parasitized hosts. A significant decrease in chlorophyll a level of approximately 32% was detected in poplars infested with mistletoe, followed by infested apples and plums with pigment reductions of 29.25% and 9.65%, respectively. The content of total phenols and flavonoids in the parasitized trees was higher compared to the non-parasitized ones. In the case of poplar, which presented the highest incidence of mistletoe infestation (70.37%), the content of total phenols in the leaves was two times higher compared to non-infested leaves. Based on HPLC chromatographic analysis, leaves of mistletoe growing on apple (VAM) had the highest content of phenolic acids (7.833 mg/g dw), followed by mistletoe leaves on poplar (VAO) and plum (VAP) (7.033 mg/g dw and, respectively, 5.559 mg/g dw). Among the flavonols, the predominant component was Rhamnazin glucosides in the amount of 1.025 ± 0.08 mg/g dw in VAO, followed by VAP and VAM (0.514 ± 0.04 and 0.478 ± 0.04 mg/g dw, respectively). Although our results show that mistletoe negatively influences the host trees, it is still a valuable plant that must be exploited to bring benefits to human health.

Antitumor effects ofrhamnazinon sorafenib-treated human hepatocellular carcinoma cell lines via modulation of VEGF signalingand PI3K/NF-κBp38/caspase-3 axes cross talk

AIMS

Hepatocellular carcinoma (HCC) is the most common livermalignancy,characterized by dysregulation of multiple oncogenicsignaling pathways, including the VEGF/PI3K/NF-κBandp38 MAPKaxes.Sorafenib is a multikinase inhibitor that targetsRaf kinases and receptor tyrosine kinases,which mediateHCC angiogenesis.Rhamnazinis a VEGFR2 signaling inhibitor, whichinhibits the phosphorylation of Vascular endothelial growth factor receptor 2(VEGFR2) and its downstream signaling regulators. This study was designed toassess the antitumor effects of rhamnazinon human HCC cell lines treated with sorafenib, and to investigate the molecular mechanisms mediating this effect.

MAIN METHODS

HepG2 and HUH-7 HCC cell lines were used.Cell viability was assessed by MTT assay. NF-κB, p38MAPK, VEGF, VEGFR2, PI3K, and Ki67 levels were assessedusing ELISA. Caspase-3 activity was measuredcolorimetrically. VEGFR2 expression was detected by RT-PCR.

KEY FINDINGS

MTT assay revealed that the sorafenib-rhamnazin combination showed significant cytotoxicity compared with sorafenib or rhamnazin alone. The sorafenib-rhamnazin combination also showed significant inhibition of the angiogenicVEGF/VEGFR2/PI3K/NF-κBsignaling axis associated with significant upregulation of the apoptotic p38MAPK/caspase-3 axis and inhibition of Ki67, a proliferation marker in HepG2 and HUH-7 cells.

SIGNIFICANCE

Rhamnazin potentiates the chemotherapeutic effect of sorafenibvia modulation ofthe VEGF/PI3K/NF-κBsignaling axis, downregulation of VEGFR2 expression, and upregulation of the p38MAPK/caspase-3 axisin human HCC cell lines.

The alleviative effect of flavonol-type Nrf2 activator rhamnazin from Physalis alkekengi L. var. franchetii (Mast.) Makino on pulmonary disorders

Rhamnazin (RN) is a flavonol isolated from the calyxes and fruits of Physalis alkekengi L. var. franchetii (Mast.) Makino, which has been used for treating pulmonary diseases in traditional Chinese medicine. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a therapeutic target for pulmonary diseases. In the present study, the underlying mechanism and pharmacological effect of RN against pulmonary disorders are investigated. Human lung epithelial Beas-2B cell and RAW 264.7 murine macrophage-based cell models, and a cigarette smoke (CS)-induced pulmonary impairment mice model are adopted for investigation in vitro and in vivo. RN is identified to be an Nrf2 activator, which promotes Nrf2 dissociation from Keap1 via reacting with the Cys151 cysteine residue of Keap1, and suppresses Nrf2 ubiquitination. In addition, RN is able to attenuate toxicant-stimulated oxidative stress and inflammatory response in vitro. Importantly, RN significantly relieves CS-induced oxidative insult and inflammation, and RN-induced inhibition of inflammation is related to inhibition of nuclear transcription factor-κB (NF-κB) and induction of cell autophagy. In conclusion, our data indicate that RN is an activator of the Nrf2 pathway and evidently alleviates pulmonary disorders via restricting NF-κB activation and promoting autophagy. RN is a promising candidate for the therapy of pulmonary disorders.

Rhamnazin Ameliorates Traumatic Brain Injury in Mice via Reduction in Apoptosis, Oxidative Stress, and Inflammation

BACKGROUND

Traumatic brain injury (TBI) is posing serious health challenges for people across the globe due to high morbidity and mortality. However, none of the agents prevents or limits the damage caused by TBI because of its multifactorial etiology. Thus, the discovery of novel agents which can act via several pathways could serve the purpose and afford favorable consequence against TBI. Therefore, in the present article, we intended to investigate the protective effect of rhamnazin (RMZ), a dimethoxyflavone against experimentally induced TBI in mice.

METHODS

The effect of RMZ was investigated on cerebral edema and grip test score after induction of experimental brain injury in rats. The effect of RMZ was also investigated on neuronal degeneration in brain tissues of the experimental mice via Nissl staining and flow cytometry analysis. The expression of Bax and Bcl-2 was also quantified using Western blot analysis. The level of inflammatory cytokines (TNF-α and IL-1β) and oxidative stress markers (malondialdehyde, superoxide dismutase, and glutathione peroxidase) was also determined using enzyme-linked immunosorbent assay.

RESULTS

RMZ showed a significant reduction in edema and improved grip strength. It also prevented neuronal degeneration via inhibition of neuronal apoptosis as shown by flow cytometry analysis. RMZ showed an antiapoptotic effect via reduction of Bax and increased the expression of Bcl-2 in Western blot analysis. It also showed to inhibit oxidative stress and inflammation compared to the TBI group.

CONCLUSION

Collectively, our study is first to demonstrate the protective effect of RMZ against experimentally induced TBI in rats.

Evaluation of Phytochemical Contents and In Vitro Antioxidant, Anti-Inflammatory, and Anticancer Activities of Black Rice Leaf (Oryza sativa L.) Extract and Its Fractions

Black rice leaves (Oryza sativa L.) are a major part of rice straw left in open fields after rice harvest as agricultural waste. In this study, crude ethanolic extract (CEE) and various solvent fractions (hexane (Hex), ethyl acetate (EtOAc), n-butanol (n-BuOH), and aqueous fractions) of black rice leaves were investigated for their bioactive compound contents as well as antioxidant, anti-inflammatory, and anticancer activities. The results demonstrated that among all the fractions, the n-BuOH fraction presented the greatest contents of total phenolics and flavonoids, while anthocyanins were found to be abundant in the n-BuOH and aqueous fractions, which also exhibited powerful antioxidant abilities according to DPPH and ABTS radical-scavenging assays and a reducing power assay. Regarding anti-inflammatory activity, CEE and EtOAc reduced the production of NO and cytokine secretion (PGE2, IL-6, and IL-1β) but displayed less effect on tumor necrosis factor α (TNF-α) release in lipopolysaccharide (LPS)-induced RAW 264.7 cells. They also significantly decreased iNOS and COX-2 protein expression. Additionally, the phenolics-rich ethyl acetate fraction showed the greatest activity against HepG2 liver carcinoma cells, inhibited cell growth, increased the Sub-G1 population, and induced apoptosis via mitochondrion-dependent mechanisms. In conclusion, black rice leaves, a byproduct of rice, exhibited strong antioxidant, anti-inflammatory, and anticancer capacities and might be useful for application in functional foods and the pharmaceutical industry.

Recent Approaches for Angiogenesis in Search of Successful Tissue Engineering and Regeneration

Angiogenesis plays a central role in human physiology from reproduction and fetal development to wound healing and tissue repair/regeneration. Clinically relevant therapies are needed for promoting angiogenesis in order to supply oxygen and nutrients after transplantation, thus relieving the symptoms of ischemia. Increase in angiogenesis can lead to the restoration of damaged tissues, thereby leading the way for successful tissue regeneration. Tissue regeneration is a broad field that has shown the convergence of various interdisciplinary fields, wherein living cells in conjugation with biomaterials have been tried and tested on to the human body. Although there is a prevalence of various approaches that hypothesize enhanced tissue regeneration via angiogenesis, none of them have been successful in gaining clinical relevance. Hence, the current review summarizes the recent cell-based and cell free (exosomes, extracellular vesicles, micro-RNAs) therapies, gene and biomaterial-based approaches that have been used for angiogenesis-mediated tissue regeneration and have been applied in treating disease models like ischemic heart, brain stroke, bone defects and corneal defects. This review also puts forward a concise report of the pre-clinical and clinical studies that have been performed so far; thereby presenting the credible impact of the development of biomaterials and their 3D concepts in the field of tissue engineering and regeneration, which would lead to the probable ways for heralding the successful future of angiogenesis-mediated approaches in the greater perspective of tissue engineering and regenerative medicine.