Acacetin Protects Myocardial Cells against Hypoxia-Reoxygenation Injury through Activation of Autophagy

Acacetin Alleviates Cardiac Fibrosis via TGF-β1/Smad and AKT/mTOR Signal Pathways in Spontaneous Hypertensive Rats

INTRODUCTION

Attenuating cardiac fibroblasts activation contributes to reducing excessive extracellular matrix deposition and cardiac structural remodeling in hypertensive hearts. Acacetin plays a protective role in doxorubicin-induced cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to investigate the potential molecular mechanisms underlying the protective role of acacetin on hypertension-induced cardiac fibrosis.

METHODS

Echocardiography, histopathological methods, and Western blotting techniques were used to evaluate the anti-fibrosis effects in spontaneous hypertensive rat (SHR) which were daily intragastrically administrated with acacetin (10 mg/kg and 20 mg/kg) for 6 weeks. Angiotensin II (Ang II) was used to induce cellular fibrosis in human cardiac fibroblasts (HCFs) in the absence and presence of acacetin treatment for 48 h.

RESULTS

Acacetin significantly alleviated hypertension-induced increase in left ventricular (LV) posterior wall thickness and LV mass index in SHR. The expressions of collagen-1, collagen-III, and alpha-smooth muscle actin (α-SMA) were remarkedly decreased after treatment with acacetin (n = 6, p < 0.05). In cultured HCFs, acacetin significantly attenuated Ang II-induced migration and proliferation (n = 6, p < 0.05). Moreover, acacetin substantially inhibited Ang II-induced upregulation of collagen-1 and collagen-III (n = 6, p < 0.05) and downregulated the expression of alpha-SMA in HCFs. Additionally, acacetin decreased the expression of TGF-β1, p-Smad3/Smad3, and p-AKT and p-mTOR but increased the expression of Smad7 (n = 6, p < 0.05). Further studies found that acacetin inhibited TGF-β1 agonist SRI and AKT agonist SC79 caused fibrotic effect.

CONCLUSION

Acacetin inhibits the hypertension-associated cardiac fibrotic processes through regulating TGF-β/Smad3, AKT/mTOR signal transduction pathways.

Natural Clerodendrum-derived tick repellent: learning from Nepali culture

Ticks attaching to ear canals of humans and animals are the cause of otoacariasis, common in rural areas of Nepal. The plant Clerodendrum viscosum is used in multiple indigenous systems of medicine by ethnic communities in the Indo-Nepali-Malaysian region. Visiting the Chitwan National Park, we learned that in indigenous medicine, flower extract of C. viscosum is utilized to treat digestive disorders and extracts from leaves as tick repellent to prevent ticks from invading or to remove them from the ear canal. The objective of our study was to provide support to indigenous medicine by characterizing the in vivo effect of leave extracts on ticks under laboratory conditions and its phytochemical composition. We collected plant parts of C. viscosum (leaves and flowers) and mango (Mangifera indica) leaves at the Chitwan National Park, previously associated with repellent activity to characterize their effect on Ixodes ricinus ticks by in vivo bioassays. A Q-ToF high-resolution analysis (HPLC-ESI-QToF) was conducted to elucidate phenolic compounds with potential repellent activity. Clerodendrum viscosum and M. indica leaf extracts had the highest tick repellent efficacy (%E = 80-100%) with significant differences when compared to C. viscosum flowers extracts (%E = 20-60%) and phosphate-buffered saline. Phytochemicals with tick repellent function as caffeic acid, fumaric acid and p-coumaric acid glucoside were identified in C. viscosum leaf extracts by HPLC-ESI-QToF, but not in non-repellent flower extracts. These results support the Nepali indigenous medicine application of C. viscosum leaf extracts to repel ticks. Additional research is needed for the development of natural and green repellent formulations to reduce the risks associated with ticks resistant to acaricides.

Chemical composition and cardiotropic activity of Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f

ETHNOPHARMACOLOGICAL RELEVANCE

Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. is a subshrub that is widely distributed in China, Kazakhstan, Kyrgyzstan, Mongolia, Russia, Tajikistan, Turkmenistan, and Uzbekistan. The species is used in traditional medicine for the relief of symptoms connected to cardiovascular diseases like coronary heart disease or hypertension.

AIM OF THE STUDY

was to validate traditional use of Z. clinopodioides subsp. bungeana for the treatment of coronary hearth diseases using in vivo models and to find active compounds responsible for the activity.

MATERIALS AND METHODS

Multiple extracts were obtained from the aerial parts of Z. clinopodioides subsp. bungeana using maceration, liquid-liquid extraction, CO2 extraction and ultrasound-assisted extraction. Preliminary screening studies for the evaluation of the efficacy of Z. clinopodioides subsp. bungeana extracts on the model of hemic hypoxia were performed. The most effective samples were selected and included in the main study. Stage 2 of the study evaluated the cardiotropic activity of the selected extracts on a model of chronic heart failure. Preparations were administered to animals intragastrically once a day for 28 days. For the isolation of individual compounds plant material was extracted with 96% ethanol. The obtained crude extract was sequentially extracted with n-hexane and dichloromethane and separated by chromatography on a Diaion HP-20 column. The obtained fractions were further subjected to Sephadex LH-20 column chromatography and eluted isocratically with 96% ethanol (EtOH) to yield subfractions, which were further separated by preparative HPLC to obtain 13 individual compounds.

RESULTS

Extracts obtained from Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. herb were subjected to pharmacological screening for the evaluation of their efficacy on hemic hypoxia. Based on the obtained results, out of the sixteen tested extracts two (AR and US 60%) were selected for further evaluation of their cardiotropic activity. Modeling of chronic heart failure was carried out in accordance with the following stages: 1) anesthesia with chloral hydrate at a dose of 450 mg/kg, intraperitoneally, 2) artificial ventilation of the lungs, 3) thoracotomy, 4) modeling of permanent ischemic or ischemic-reperfusion damage. Both extracts effected the indicators of contraction and output, comparable to the reference drug - Monopril. Based on the extraction methods used to obtain RAF and US60 and data from the literature, it can be assumed that they contain compounds with medium polarity, including polyphenols and terpenoids. At the next stage three previously undescribed monoterpenoid derivatives - Ziziphoric acid (1), Ziziphoroside D (2) and 6'-malonylziziphoroside A (3), along with two previously described megastigmane glucosides - blumenol C glucoside (4), blumenol C 9-O-(6'-O-malonyl-beta-D-glucopyranoside (5) and two previously described monoterpenoids 7a-hydroxymintlactone (6), 7-hydroxypiperitone (7) together with six polyphenols - pinocembrine-7-O-rutinoside (8), chrysine-7-O-rutinoside (9), acacetin-7-O-rutinoside (10), luteolin-7-O-rutinoside (11), rutin (12) and rosmarinic acid (13) were isolated from Z. clinopodioides subsp. bungeana extracts.

CONCLUSION

Our results support the traditional use of Z. clinopodioides subsp. bungeana for the treatment of coronary diseases. As a result of Z. clinopodioides subsp. bungeana extracts screening in vivo, two extracts were selected as potential cardiotropic agents. Phytochemical analysis of the plant material led to the isolation of five terpenoid derivatives, two megastigmane glycosides, five flavonoids and one cinnamic acid derivative, which could be responsible for the reported biological activity. Future experiments are required to understand the mechanisms of action for the isolated compounds.

Acacetin Inhibits Cell Proliferation and Induces Apoptosis in Human Hepatocellular Carcinoma Cell Lines

Human hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of death across the world. Recent evidence suggests that STAT3 regulates proliferative, survival, metastasis, and angiogenesis genes in HCC. Novel agents that suppress STAT3 activation can be used to prevent or treat HCC. We used a functional proteomics tumor pathway technology platform and multiple HCC cell lines to investigate the effects of acacetin (ACN) on STAT3 activation, protein kinases, phosphatases, products of STAT3-regulated genes, and apoptosis. ACN was found to inhibit STAT3 activation in a dose- and time-dependent manner in HCC cells. Upstream kinases c-Src, Janus-activated kinase 1, and Janus-activated kinase 2 were also inhibited. The ACN inhibition of STAT3 was abolished by vanadate treatment, suggesting the involvement of tyrosine phosphatase activity. ACN was found to suppress the protein expression of genes involved in proliferation, survival, and angiogenesis via STAT3 inhibition. ACN appears to be a novel STAT3 inhibitor and may be a promising therapeutic compound for application in the treatment of HCC and other cancers.

Acacetin Protects against Non-Alcoholic Fatty Liver Disease by Regulating Lipid Accumulation and Inflammation in Mice

We previously demonstrated that acacetin reduces adipogenesis in adipocytes, and decreases lipid accumulation in visceral adipocyte tissue. Here we investigated whether acacetin regulated the mechanisms of lipogenesis and inflammation in non-alcoholic fatty liver disease (NAFLD) in obese mice. Male C57BL/6 mice were fed a high-fat diet (HFD), and then administered acacetin by intraperitoneal injection. Acacetin reduced body weight and liver weight in obese mice. Acacetin-treated obese mice exhibited decreased lipid accumulation, increased glycogen accumulation, and improved hepatocyte steatosis. Acacetin regulated triglycerides and total cholesterol in the liver and serum. Acacetin decreased low-density lipoprotein and leptin concentrations, but increased high-density lipoprotein and adiponectin levels in obese mice. Acacetin effectively weakened the gene expressions of transcription factors related to lipogenesis, and promoted the expressions of genes related to lipolysis and fatty acid β-oxidation in liver. Acacetin also reduced expressions of inflammation-related cytokines in the serum and liver. Oleic acid induced lipid accumulation in murine FL83B hepatocytes, and the effects of acacetin treatment indicated that acacetin may regulate lipid metabolism through the AMPK pathway. Acacetin may protect against hepatic steatosis by modulating inflammation and AMPK expression.

Acacetin as a Potential Protective Compound against Cardiovascular Diseases

Acacetin (5,7-dihydroxy-4′-methoxyflavone) is the major bioactive component of the traditional Chinese medicine “Snow lotus”. As a natural flavonoid compound, it has been shown to have good pharmacological effects such as anti-inflammatory, anticancer, and anti-obesity. Among them, its prominent role in cardiovascular diseases (CVD) has received extensive attention from scholars in recent years. In this review, the protective effects of acacetin on a variety of cardiovascular diseases, as well as the existing problems and prospects, are discussed and summarized. This review also highlights the great potential of acacetin, a natural-derived Chinese medicine, as a cardiovascular agent candidate.