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Rhubarb is a common herb used in traditional Chinese medicine. However, few publications exist about its pharmacokinetic profiles in animals or healthy volunteers. Whether retention enema administration of rhubarb extract affects its pharmacokinetics as well as its tolerability is unknown. Therefore, we set out to compare the pharmacokinetic parameters of rhein administered by retention enemas with those of conventional oral dosing of rhubarb extract. Eight healthy male volunteers were enrolled in a prospective crossover study. All subjects received a single dose of rhubarb extract (50 mg·kg^-1) on two separate occasions, once orally, once by a retention enema. Rhein plasma concentration was measured by HPLC. The C_max, AUC_0-∞, AUMC were significantly higher in oral administration than those in retention enema administration (p < 0.05), while V_d of rhein after oral administration of rhubarb extract was significantly lower (p < 0.05) than that after retention enema administration. However, no statistically significant differences between the two treatments were observed for any of the other pharmacokinetic parameters (T_max, t_1/2, MRT_0-∞, CL). Dosage adjustment is advisable for retention enema administration of rhubarb extract in patients.

Rhubarb has been used to decrease plasma cholesterol levels and reduce vascular endothelial cellular damage in recent years. However, it is not known whether reported lipid-lowering effects are associated with the improvement of endothelial function. This work aimed to elucidate the therapeutic effects of rhubarb on serum lipids and brachial artery endothelial function, as well as to investigate the relationship between them. One hundred and three patients with atherosclerosis were randomly divided into two groups: patients in the control and the trial group received a placebo and rhubarb, respectively, in addition to the 6 month baseline therapy. Serum lipids and brachial artery endothelial functions were measured in all patients before and after treatment. A total of 83 patients completed the 6-month follow-up protocol. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in the trial group decreased significantly and LDL-C was significantly lower than that in the control group. Flow-mediated dilation (FMD) in the trial group was significantly higher after treatment in comparison to the baseline and to the control group. Improvement in FMD correlated with the decreased magnitude of TC and LDL-C levels. The results obtained appeared to confirm that rhubarb significantly improves endothelial function mainly due to lipid-lowering effects in patients with atherosclerosis.

Coxsackievirus B₃(CVB₃) infection is the major cause of viral myocarditis, as well as dilated cardiomypathy. Rhubarb is one of the oldest and best-known traditional Chinese medicines. We initiated this study to determine the antiviral effect of an ethanol extract from the roots and rhizoma of Rheum palmatum (R. palmatum, one of the Chinese Rhubarbs), against CVB₃ in tissue culture cells and in a mouse model. The ethanol extract from R. palmatum showed significant inhibitory activity against CVB₃ on HEp-2 cells when added after infection, with IC₅₀ of 4 μg/ml, TI of 10. The medicated mouse serum still contained the pharmaceutical compound 24 h after intraperitoneal injection, and exhibited an antiviral effect on CVB₃-infected cells, especially in the 0.3 and 0.5 g/kg/day treatment groups. Furthermore, the CVB₃-infected mice were treated with the extract solution with dosages of 0.3 g/kg/day beginning 24 h post-CVB₃ exposures. The ethanol extract treated mice showed alleviated clinical signs, better survival rate, prolonged MTD and decreased viral titers compared to the virus control group. Our results indicate that the ethanol extract from R. palmatum has the anti-CVB₃ activity in vitro and in vivo and thus provides a re-evaluation of this old remedy with a broad therapeutic potential.

A prospective multicenter clinical trial was conducted to compare the beneficial effects of a Chinese herbal medicine formula Jiangzhuoqinggan (JZQG) and western antihypertension drug irbesartan. JZQG is mainly composed of rhubarb, coptis, cassia, and uncaria. A total of 240 patients with mild to moderate hypertension were enrolled in the trial. Patients were assigned into two groups after screening: JZQG group and the irbesartan group. After four weeks of treatment, we compared the changes in routine blood pressure, 24 h ambulatory blood pressure, and waist circumference. There was a significant reduction in systolic blood pressure and diastolic blood pressure in the JZQG group (both p < 0.01). There were no significant differences between the reduction of systolic and diastolic blood pressures in the two treatment groups. From the 24 h ambulatory blood pressure measurement, the JZQG group showed a greater reduction in both systolic and diastolic blood pressures (in both daytime and nighttime) than the irbesartan group. Furthermore, there was a significant difference in waist circumference in the JZQG group (1.51 cm reduction; P < 0.05) but not the irbesartan group (0.42 cm). Thus, the JZQG formula may have therapeutic value in patients with both hypertension and metabolic syndrome.

Rhubarb, the rhizome of Rheum palmatum L. (RP), is a popular herb used in Chinese medicine prescriptions. RP contains a variety of polyphenolic anthraquinones, such as aloe-emodin, rhein, emodin and chrysophanol. Our previous study found that the anthraquinones in RP existed predominantly as glucuronides/sulfates in the bloodstream, which were putative substrates of MRPs. Methotrexate (MTX) is a widely used immunosuppressant and anticancer agent, but it has a narrow therapeutic index. The transcellular transport of MTX is mediated by multidrug resistance associated proteins (MRPs). This study investigated the effects of coadministration of RP on MTX pharmacokinetics in rats. The possible involvement of MRP 2 was verified by using cell models and various typical MRP 2 substrates. The results showed that coadministration of 0.5 mg/kg of RP significantly increased the AUC_0-t and MRT of MTX by 307% and 364%, and 1.0 g/kg of RP significantly increased the AUC_0-t and MRT of MTX by 602% and 419%, respectively. Cell line studies indicated that the activity of MRP 2 was inhibited by the metabolites of RP and rhein. In conclusion, concomitant administration of RP markedly increased the systemic exposure of MTX via inhibiting MRP 2-mediated excretion.

The intestine plays a vital role in the pathophysiology of sepsis development. The objective of the present study was to explore the effects of rhubarb on intestinal microcirculation in septic rats. We used moorFLPI laser speckle imaging to detect the blood flow of the intestinal mucosa and wall. Using an ELISA, we assayed the concentration of lactate (L) and pyruvic acid (P) in the intestinal tissue to calculate the ratio of lactate to pyruvic acid (L/P ratio). To observe the intestinal mucosal capillaries, gelatin and ink were perfused into the intestine and subsequently stained with hematoxylin and eosin (HE) to measure the ratio of the vessel area. We then used immunohistochemistry to measure CD31 expression. Using an MTT assay, the effect of the rhubarb extract on the proliferation of human umbilical vein endothelial cells (HUVECs) was analyzed. The blood flow in the intestinal wall and mucosa of the control, sham and rhubarb-treated groups was significantly higher, while the sepsis group had relatively low blood flow. The L/P ratio in the intestinal tissue was larger in the sepsis group than in the other three groups. The microvascular area (MVA) in the sepsis group was smaller than in the control group, sham group or rhubarb group. Positive expression for CD31 was observed in the cytoplasm of vascular endothelial cells. The intestinal mucosal capillaries were reduced in septic rats as compared to the other three groups. HUVEC proliferation was enhanced by the rhubarb extract monomers at 1 μmol/L, but suppressed at higher concentrations of 10 to 100 μmol/L. These results suggest that pre-treatment with rhubarb prior to sepsis induction promotes the expansion of the intestinal mucosal capillaries, protects intestinal mucosal capillary endothelial cells and increases the number of functional intestinal capillaries.

Obesity is a serious medical problem worldwide. As a holistic therapy, traditional Chinese medicine (TCM) may have a potential in obesity management. In this controlled trial, we evaluated the safety and effectiveness of Xin-Ju-Xiao-Gao-Fang (XJXGF), a TCM herbal formulation, in 140 obese subjects over a 24-week period. The XJXGF formula mainly consists of rhubarb, coptis, semen cassia, and citrus aurantium. Subjects with body mass index (BMI) 28–40 kg/m² were recruited at 5 centers in China. We assessed the changes in subjects' body weight, its related parameters, and the reduction of insulin resistance (IR) after administration of XJXGF formula or low-dose XJXGF (10% of the XJXGF formula, as control). After 24-week treatment, among participants in the XJXGF formula group and low-dose XJXGF group, the mean ± SE changes in the body weight were -3.58 ± 0.48 and -1.91 ± 0.38 kg, respectively (p < 0.01). The changes in the IR-index of two groups were -2.65 ± 1.04 and -1.58 ± 1.3, respectively (p < 0 .05). There were no serious adverse events reported during the 24-week trial. Participants reported 7 minor adverse events, 4 in the XJXGF formula group and 3 in the low-dose XJXGF group (p = 0.578). Future studies are needed to investigate the clinical utility of this TCM formulation in the treatment of obese subjects.

Critical care medicine is a medical specialty engaging the diagnosis and treatment of critically ill patients who have or are likely to have life-threatening organ failure. Sepsis, a life-threatening condition that arises when the body responds to infection, is currently the major cause of death in intensive care units (ICU). Although progress has been made in understanding the pathophysiology of sepsis, many drawbacks in sepsis treatment remains unresolved. For example, antimicrobial resistance, controversial of glucocorticoids use, prolonged duration of ICU care and the subsequent high cost of the treatment. Recent years have witnessed a growing trend of applying traditional Chinese medicine (TCM) in sepsis management. The TCM application emphasizes use of herbal formulation to balance immune responses to infection, which include clearing heat and toxin, promoting blood circulation and removing its stasis, enhancing gastrointestinal function, and strengthening body resistance. In this paper, we will provide an overview of the current status of Chinese herbal formulations, single herbs, and isolated compounds, as an add-on therapy to the standard Western treatment in the sepsis management. With the current trajectory of worldwide pandemic eruption of newly identified Coronavirus Disease-2019 (COVID-19), the adjuvant TCM therapy can be used in the ICU to treat critically ill patients infected with the novel coronavirus.

Constipation is a very common medical condition worldwide, negatively affecting patients’ quality of life and healthcare system. Rhubarb, senna leaf, and aloe are three frequently used herbal medications for achieving regular bowel movement. Rhubarb is also a key ingredient in MaZiRenWan, a Chinese medicine formula used every so often for constipation in oriental countries. We reviewed and summarized the major chemical components from these three botanicals, including dianthrones, anthraquinone glycosides, free anthraquinones, and other polyphenols. The purgative actions of these constituents have been compared. Anthraquinone, especially its dianthrone compounds such as sennoside A and sennoside B, as natural stimulant laxatives, possesses significant effects to promote gastrointestinal motility and relieve functional constipation. Furthermore, the safety, reported side effects, and other benefits of anthraquinone compounds are presented. To date, many anti-constipation natural products are being used but their research is relatively limited, and thus, more investigations in this field are indeed needed.