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Background: Despite the availability of various classes of antihypertensive medications, a large proportion of hypertensive individuals remain resistant to treatments. The reason for what contributes to low efficacy of antihypertensive medications in these individuals is elusive. The knowledge that gut microbiota is involved in pathophysiology of hypertension and drug metabolism led us to hypothesize that gut microbiota catabolize antihypertensive medications and compromised their blood pressure (BP)-lowering effects. Methods and Results: To test this hypothesis, we examined the BP responses to a representative ACE (angiotensin-converting enzyme) inhibitor quinapril in spontaneously hypertensive rats (SHR) with or without antibiotics. BP-lowering effect of quinapril was more pronounced in the SHR+antibiotics, indicating that gut microbiota of SHR lowered the antihypertensive effect of quinapril. Depletion of gut microbiota in the SHR+antibiotics was associated with decreased gut microbial catabolism of quinapril as well as significant reduction in the bacterial genus Coprococcus . C. comes , an anaerobic species of Coprococcus , harbored esterase activity and catabolized the ester quinapril in vitro. Co-administration of quinapril with C. comes reduced the antihypertensive effect of quinapril in the SHR. Importantly, C. comes selectively reduced the antihypertensive effects of ester ramipril but not nonester lisinopril. Conclusions: Our study revealed a previously unrecognized mechanism by which human commensal C. comes catabolizes ester ACE inhibitors in the gut and lowers its antihypertensive effect.

Introduction Drug resistant HTN (rHTN) affects around 15% to 20% of hypertensive (HTN) patients. The underlying mechanisms of resistance to treatment remain poorly understood. The majority of angiotensin‐converting enzyme inhibitors (ACEi) are esters, whereby we hypothesized that select gut microbiota hydrolyze ACEi rendering lower efficacy (Figure 1A). To test this hypothesis, we investigated if and which gut microbe modulates the effectiveness of ACEi. Methods Vancomycin, Meropenem and Omeprazole (VMO) were given to 16‐week‐old male Spontaneously Hypertensive Rats (SHR) at 50 mg/kg/day for five days. A single dose of 8mg/kg Quinapril was orally administered to both SHR and SHR+VMO, and blood pressure (BP) was recorded via radio‐telemetry. Liquid chromatography–mass spectrometry was used to measure the catabolism of quinapril. The hydrolysis of p‐nitro‐phenylbutyrate was used to measure the activity of bacterial esterase. 16S rRNA sequencing was used to study the microbial composition. At last, ester ACEi ramipril and non‐ester lisinopril were co‐administered with Coprococcus comes, respectively, to generalize the effect of C. comes on ACEi's effectiveness. Results Compared to the SHR, depletion of gut microbiota in the SHR+VMO group preserved the BP lowering effect of Quinapril, an ester ACEi (Figure 1B). The SHR+VMO group showed (1) reduced Coprococcus (Figure 1C); (2) lower esterase activity per gram of cecal microbiota to hydrolyze quinapril (Figure 1D); (3) a 50% lower reduction in quinapril quantity (nmol) after incubation with 1mg of cecal lysate for 3 hr (Figure 1E). C. comes,a species in Coprococcusgenus, catabolized quinapril in vitro and reduced its BP‐lowering effects in the SHR (Figure 2A‐B). Importantly, C. comes also reduced the BP‐lowering effects of ramipril (ester), but not lisinopril (non‐ester) in the SHR (Figure 2C‐D). Conclusion These observations constitute the first report of an unrecognized role of a select gut microbe, C. comes, in reducing the effectiveness of ester ACEi. As such, this mechanistic study serves as the foundation for expanding clinical management of antihypertensive drug resistance via manipulation of gut microbiota.

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Allium cepa is used for the prevention and treatment of hyperlipidemia-related diseases such as atherosclerosis in the folk. This study was mainly aimed at investigating the effects of A. cepa extract (ACE) enriched in polyphenols on hyperlipidemia Sprague-Dawley (SD) experiment rat models. The levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), malondialdehyde (MDA), and superoxide dismutase (SOD) activity in serum and liver were measured using ELISA kits. In addition, hematoxylin-eosin (HE) technique was used to observe the liver and the aortic arch pathology. Moreover, western blotting (WB) method was applied to analyze LDL receptor (LDLR) and 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase (HMGCR) in liver. As a result, quercetin (2.42 mg/g DW) and isoquercitrin (4.60 mg/g DW) were the main constituents of ACE using HPLC analysis. Furthermore, ACE reduced the levels of TC, TG, LDL-C, and MDA, and increased HDL levels and elevated SOD activity both in serum and liver in hyperlipidemic SD rats (p < .05). HE results showed that liver fat drops of the rats in ACE group were obviously decreased, and the lipid and foam cells of the aortic arch of the rats in ACE group were markedly ameliorated. WB results showed that ACE promoted the degradation of HMGCR and increased LDLR expression in liver (p < .05). In conclusion, ACE alleviated hyperlipidemia with downregulation of HMGCR and upregulation of LDLR. Practical applications Atherosclerosis, a major cardiovascular disease, is the leading cause of mortality and morbidity in the developed countries. Moreover, accumulating data indicate that, during atherosclerosis development, hyperlipidemia is an important risk factor. To date, hyperlipidemia is mainly treated with hyperlipidemic agents including statins, in spite of the side effects and poor tolerance in some patients. In addition, Allium cepa is a medicinal and edible plant. Furthermore, A. cepa is used for the prevention and treatment of hyperlipidemia-related diseases such as atherosclerosis in the folk. But the underlying mechanism is still unclear. In fact, this research showed that A. cepa extract (ACE) alleviated hyperlipidemia with downregulation of HMGCR and upregulation of LDLR, suggesting that ACE might be a potential option for hyperlipidemia as non-statin lipid-lowering agent. How to cite this article: Li W, Yang C, Mei X, et al. Effect of the polyphenol-rich extract from Allium cepa on hyperlipidemic sprague-dawley rats.

Background: The spontaneously hypertensive rat (SHR) is extensively used to study hypertension. Gut microbiota dysbiosis is a notable feature in SHR for reasons unknown. Immunoglobulin A (IgA) is a major host factor required for gut microbiota homeostasis. We hypothesized that inadequate IgA contributes to gut microbiota dysbiosis in SHR. methods: IgA was measured in feces, cecum, serum, liver, gut-associated lymphoid tissue, and milk from SHR and Wistar Kyoto rats. IgA regulatory factors like IgM, IgG, and pIgR (polymeric immunoglobulin receptor) were analyzed. IgA and IgG antibodies and blood pressure (BP) were measured before and after administrating a bacterial antigen (ie, flagellin). Results: Compared with Wistar Kyoto rats, SHR displayed remarkably near-deficient IgA levels accompanied by compensatory increases in serum IgM and IgG and gut-liver pIgR expression. Inadequate milk IgA in SHR emphasized this immune defect stemmed from the neonatal stage. Reduced IgA + B cells in circulation and Peyer patches indicated a possible reason for the lower IgA in SHR. Noteworthy, a genetic insufficiency was unlikely because administering flagellin to SHR induced anti-flagellin IgA antibodies. This immune response surprisingly accelerated hypertension development in SHR, suggesting IgA quiescence may help maintain lower BP. Conclusions: This study is the first to reveal IgA deficiency in SHR as one host factor associated with gut microbiota dysbiosis and invigorates future research to determine the pathophysiological role of IgA in hypertension.

Context: In China, the herb Sophora tonkinensis Gagnep. (Fabaceae, ST) (Committee of National Pharmacopeia. 2015) exhibits anti-inflammatory, antitumor, and antiviral effects. However, to date, there have been few studies on its gastrointestinal effect. Objective: The gastrointestinal effect of the methanol extract of ST rhizome (STR) was evaluated. Materials and methods: Study was conducted from February to December 2018. In vivo, antidiarrheal activity of STR (125, 250 and 500 mg/kg; orally) in castor oil-induced diarrheal mice was studied. In vitro, the effects of STR (0.01-10 mg/mL) on the isolated tissue preparations of rabbit jejunum were also investigated, the rabbit jejunum stripes were pre-contracted with Ach (10 À5 M), K þ (60 mM) and tested in the presence of STR, the possible spasmolytic effect was analyzed in the pretreatment of the jejunum preparations with STR or verapamil in Ca 2þ -free high-K þ (60 mM) solution containing EDTA. Results: STR (125, 250 and 500 mg/kg) exhibited antidiarrheal activity. STR (0.01-10 mg/mL) completely relaxed spontaneously contracting, Ach (10 À5 M) and high K þ (60 mM) induced contracted jejunum with an EC 50 value of 0.66 (0.49-0.96), 0.39 (0.28-0.44) and 0.17 (0.10-0.21), similar to verapamil. Concentration-response curves of CaCl 2 could be significantly moved to the right and down in the presence of STR (0.3, 1 mg/mL). Discussion and conclusions: Results suggest the presence of antidiarrheal activity and spasmolytic effects of STR, possibly mediated through Ca 2þ channel blocking activity, providing the pharmacological basis for its traditional uses in gastrointestinal disorders.

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