Imperatorin alleviates metabolic and vascular alterations in high-fat/high-fructose diet-fed rats by modulating adiponectin receptor 1, eNOS, and p47phox expression

Mitigation effect of galangin against aortic dysfunction and hypertrophy in rats with metabolic syndrome

Vascular alterations induced by a high-fat diet (HFD) are involved in the development of hypertension. Galangin, a flavonoid, is the major active compound isolated from galangal and propolis. The objective of this study was to investigate the effect of galangin on aortic endothelial dysfunction and hypertrophy, and the mechanisms involved in HFD-induced metabolic syndrome (MS) in rats. Male Sprague-Dawley rats (220-240 g) were separated into three groups: control + vehicle, MS + vehicle, and MS + galangin (50 mg/kg). Rats with MS received HFD plus 15% fructose solution for 16 weeks. Galangin or vehicle was orally administered daily for the final four weeks. Galangin reduced body weight and mean arterial pressure in HFD rats (p < 0.05). It also reduced circulating fasting blood glucose, insulin, and total cholesterol levels (p < 0.05). Impaired vascular responses to the exogenous acetylcholine observed in the aortic ring of HFD rats were restored by galangin (p < 0.05). However, the response to sodium nitroprusside did not differ between the groups. Galangin enhanced the expression of the aortic endothelial nitric oxide synthase (eNOS) protein and increased circulating nitric oxide (NO) levels in the MS group (p < 0.05). Aortic hypertrophy in HFD rats was alleviated by galangin (p < 0.05). Increases in tumour necrosis factor-alpha (TNF-α), interleukin (IL)-6 levels, angiotensin-converting enzyme activity and angiotensin II (Ang II) concentrations in rats with MS were suppressed in galangin treated group (p < 0.05). Furthermore, galangin reduced the upregulation of angiotensin II type I receptor (AT1R) and transforming growth factor-beta (TGF-β) expression in rats with MS (p < 0.05). In conclusion, galangin alleviates metabolic disorders and improves aortic endothelial dysfunction and hypertrophy in the MS group. These effects were consistent with increased NO availability, reduced inflammation, and suppressing Ang II/AT1R/TGF-β signalling pathway.

Imperatorin Positively Regulates Melanogenesis through Signaling Pathways Involving PKA/CREB, ERK, AKT, and GSK3β/β-Catenin

The present study investigated the melanogenic effects of imperatorin and isoimperatorin and the underlying mechanisms of imperatorin using a mouse melanoma B16F10 model. Interestingly, treatment with 25 μM of either imperatorin or isoimperatorin, despite their structural differences, did not produce differences in melanin content and intracellular tyrosinase activity. Imperatorin also activated the expression of melanogenic enzymes, such as tyrosinase (TYR) and tyrosinase-related proteins TYRP-1 and TYRP-2. Mechanistically, imperatorin increases melanin synthesis through the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA)/cAMP-responsive element-binding protein (CREB)-dependent upregulation of microphthalmia-associated transcription factor (MITF), which is a key transcription factor in melanogenesis. Furthermore, imperatorin exerted melanogenic effects by downregulating extracellular signal-regulated kinase (ERK) and upregulating phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/glycogen synthesis kinase-3β (GSK-3β). Moreover, imperatorin increased the content of β-catenin in the cell cytoplasm and nucleus by reducing the content of phosphorylated β-catenin (p-β-catenin). Finally, we tested the potential of imperatorin in topical application through primary human skin irritation tests. These tests were performed on the normal skin (upper back) of 31 volunteers to determine whether 25 or 50 µM of imperatorin had irritation or sensitization potential. During these tests, imperatorin did not induce any adverse reactions. Taken together, these findings suggest that the regulation of melanogenesis by imperatorin can be mediated by signaling pathways involving PKA/CREB, ERK, AKT, and GSK3β/β-catenin and that imperatorin could prevent the pathogenesis of pigmentation diseases when used as a topical agent.

Secreted frizzled-related protein 3 alleviated cardiac remodeling induced by angiotensin II via inhibiting oxidative stress and apoptosis in mice

Increased expression of secreted frizzled related protein 3 (SFRP3) is associated with adverse outcomes of heart failure. The purpose of this study was to investigate the effect of SFRP3 on cardiac remodeling and its mechanism. Cardiac remodeling was induced by angiotensin II (Ang II) infusion in the mice, and in the neonatal rat cardiomyocytes (NRCM) treated with Ang II. The expression decreased in the heart of mice, and NRCM and HL-1 cells with Ang II treatment. Ang II-induced hypertrophy and fibrosis of heart in mice were attenuated by upregulation of SFRP3, and were further deteriorated by downregulation of SFRP3. Ang II-induced hypertrophy of NRCM and HL-1 cells were improved by SFRP3 overexpression, and were further deteriorated by SFRP3 knockdown. The oxidative stress increased in the heart of Ang II-treated mice, and this enhancement was inhibited by overexpressing of SFPR3, and was worsened by downregulation of SFPR3. These outcomes suggested that upregulation of SFPR3 could improve cardiac remodeling via inhibition of oxidative stress.

The Angelica dahurica: A Review of Traditional Uses, Phytochemistry and Pharmacology

Angelica dahurica (A. dahurica) root is a famous edible medicinal herb that has been used in China for thousands of years. To date, more than 300 chemical constituents have been discovered from A. dahurica. Among these ingredients, coumarins and volatile oils are the major active compounds. Moreover, a few other compounds have also been isolated from the root of A. dahurica, such as alkaloids, phenols, sterols, benzofurans, polyacetylenes and polysaccharides. Modern pharmacological studies demonstrated that the root of A. dahurica and its active components displayed various bioactivities such as anti-inflammation, anti-tumor, anti-oxidation, analgesic activity, antiviral and anti-microbial effects, effects on the cardiovascular system, neuroprotective function, hepatoprotective activity, effects on skin diseases and so on. Based on these studies, this review focused on the research publications of A. dahurica and aimed to summarize the advances in the traditional uses, phytochemistry and pharmacology which will provide reference for the further studies and applications of A. dahurica.