Rheum tanguticum. R. palmatum. R. officinale.  大 黄 Dà huáng    Rhubarb     
Rheum tanguticum- used in Northern China. R. officinale- used in Southern China.
PART USED: Dried root/rhizome- The drug is dug in the late Autumn when the stem and leaves being to wither, or in early spring before the plant begins to sprout, then dried. It is best to harvest plant at least three years old. It is used unprepared, or stir baked with wine, or carbonised.
   FLAVOR: Bitter   CHANNEL: Spleen, Large Intestine, Liver, Stomach, Pericardium, Heart
FUNCTIONS- Strong laxative
GROUP: Descending- Cooling purgatives
1. Drains Heat and purges accumulations.[5] Sedate excess Heat.[4] Purge Heat.[1]
2. Purgative- only works for one bowel movement about 6 hours and may produce pain.[4] Push down accumulations, promote relief of coagulations. Regulates bowel movement. Corrects constipation.[1,4] Loosening bowels. Stimulate digestive tract creating diarrhea- lubricating intestine to produce bowel moements.[4] Strengthen Stomach.[4]
3. Drains Damp Heat via the stool.[5]
4. Drains Heat from the Blood,[4,5] and stop bleeding due to Hot symptoms.[4] Dispels Blood stasis.[5]
5. Clearing toxins. Promoting blood circulation and removing blood stasis. Breaks down clots.[1]
6. Diuretic.[4]
ACTIONS
INDICATIONS- Rhubarb is an essential drug for internal stagnation and constipation, and for treating both recent and long term Blood stasis.
1. Constipation due to full Heat and/or constipation due to stagnation of food in the bowels.[4] Intestinal Heat excess; High fever, produse sweating, thirst, constipation, abdominal distention and pain, delirium, T- yellow tongue coating, P- full.[5] Constipation caused by Damp Heat jaundice.[1,4] Hard stools.[4]
2. Hematemesis and epistaxis due to invasion of Blood by Heat;[5] blood shot eyes, sore that, gum swelling and pain due to flaring up of fire.[5] Hematemesis and hemorrhoids or Heat accumulating in the Intestines.[5] Vomiting of blood[5] or epistaxis accompanied by constipation.[5]
3. Sores, carbuncles and other pyogenic infections due to noxious Heat, and burns.[5] At the early stage of cellulitis on the back accompanied with constipation and forceful pulse. Appendicitis with abdominal pain. Burns and scalds.[5] Toxic Heat boils and ulcers.[1]
4. Postpartum abdominal pain due to blood stasis, mass in the abdomen, traumatic injuries, and syndrome of blood retention. Blood stasis in the Liver and Spleen with distended abdomen and superficial venous engorgement. Traumatic injuries with blood stasis in the hypochondrium and unbearable pain. Blood retention due to accumulation of Heat in the lower Heater causing stagnation of blood and Qi manifested as feeling of fullness causing rigidity in the lower abdomen, madness but normal urination.
5. Removing Damp Heat and chologogue action to relieve jaundice,[4,5]or acute, hot dysenteric dysorders.[5] Stranguria.[4] Benefits Gall Bladder and gallstones.[4]
6. Blood clots that need expulsion.[1] Suppressed menstruation. Amenorrhea, immobile abdominal masses, or fixed pain due to Blood stasis. Also for Blood stasis due to traumatic injury or Intestinal abscesses.[5]
7. Painful urinary dysfunction.[5]
8. Worm caused or indulgence caused dysentery.[1]
CONTRAINDICATIONS: Fresh Da huang has a very strong descending action and is therefore suitable for treating full Heat in Blood or stagnation in the Stomach and intestines.[4] If Qi or Blood deficient conditions only small amounts can be used.[5] Exterior disorders.[5] Cold from deficiency of the spleen and Stomach.[5]
Pregnant, mensturation, or post partum women,[5] must use Da Huang with caution because it can induce contractions of the uterus.
Women must use Da Huang with caution if they have just given birth or if they are menstruating because it causes uterine contractions and can prevent blood from clearing.[3,4]
Breast feeding because the milk turns yellow and the infant develops diarrhea.[4] Nursing mothers becuase the active ingredients enter the milk.[5]
Chronic constipation because in such a case there is a deficient Qi condition.[4]
PATENT COMBINATIONS
- Heat and Damp in lower Heater; Oliguria and dysuria. Clears Damp Heat, purges Fire, unblocks painful urinary dysfunction and promotes diuresis Dianthus combination- Ba zheng san
- Qi deficiency and Qi stagnation: Regulates the Qi in the middle Heater, tonifies the Qi, promotes bowel movement Aquilaria Combination- Chen xiang hua qi wan.
- Accumulation of internal Heat and exterior Wind Heat: Releases exterior Wind Heat, drains Heat, promotes bowel movement Siler & Platycodon- Fang feng tong sheng wan.
- Dryness in the Stomach and Intestines due to heat, causing constipation: Moistens the Intestines, drains heat, moves the Qi and unblocks the bowels Apricot Seed & Linum- Ma zi ren wan.
- Skin lesions due to Heat and toxicity or Damp Heat: Clears Heat and resolved toxicity, clears Damp Heat Dandelion & Lycium- Qing re an chuang pian.
- Constipation due to Blood and Yin deficiency with stagnation of Qi: Moistens the Intestines, regulates the Qi, nourishes the Yin and the Blood, unblocks the bowels Linum & Rhubarb- Run chang wan.
- Indigestion due to food stagnation: Reduces Food stagnation, regulate the Stomach and Intestines, disperses Accumulation Raphanus & Crataegus- Xiao shi bao tong chong ji.    
COMBINATIONS
PREPARATIONS: Decoction  Dried root/rhizome 3-12 g for each dose.[1,4,5]
For purgation, it is better to boil it later than other drugs, or to steep it in boiling water for an oral dose.[3] Da Huang is usually added to a formula 4 to 5 minutes before boiling ceases. Boiling for longer nullifies its effectiveness.[5] When dispersing Dampness and Heat, it is boiled for a short time longer.[4]
The unprepared drug has drastic actions and the prepared drug has mild actions. For promoting blood circulation, it should be used stir-baked with wine and for hemostasis, the carbonised drug is preferred.[3]
For external use, a  suitable amount may be crushed and mixed up with water for compress.[1] Treated with wine or vinegar strengthens its Blood invigorating action, and charred to treat bleeding.[5] May also be applied topically as a powder or wash. Good quality is heavy, hard, solid, oily, bitter (but not astringent), and golden brown in color.[5]

References
Inner Path can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Constituents.
Research.
English rhubarb is similar but milder in action. It has been shown to have both astringent and cathartic properties.[1] The anthraquinones are laxative and the tannins astringent.[2]
In Chinese medicine rhubarb is also very highly regarded; it is used for jaundice, abdominal pains, indigestion, ammenorrhea, carbuncles, scalds and burns. It was shown to have cholinergic action in rodents, to enhance peristalsis and increase the water content of stools. In low does it increased gastric secretion and therefore acted as an appetite stimulant, and increased the secretion of bile. Emodin was shown to be a powerful antispasmodic in isolated rat intestine. The antiinflammatory and antiseptic action was also demonstrated.[3]
References
[1] Fairbairn, J. W. (1976) Pharmacol. 14 (Suppl.1), 48
[2] Potter's New Cyclopaedia of Botanical Drugs and Preparations  R.C. Wren Revised by Elizabeth M. Williamson and Fred J Evans. First published in Great Britain in 1988 and reprinted in 1989 and 1994 by the C. W. Daniel Company Limited. 1 Church Path, Saffron Walden Essex. Published 1988 Printed and bound by Biddles, Guildford ISBN 085207 1973.
[3] Pharmacology and Applications of Chinese Materia Medcia Vol 1, Ed. H. Chan and P. But, Pub. World Scientific (1986) Singapore

The inhibitory effect of Rheum palmatum against coxsackievirus B3 in vitro and in vivo.
Xiong HR, Shen YY, Lu L, Hou W, Luo F, Xiao H, Yang ZQ.
Abstract
Coxsackievirus B(3)(CVB(3)) 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 CVB(3) in tissue culture cells and in a mouse model. The ethanol extract from R. palmatum showed significant inhibitory activity against CVB(3) on HEp-2 cells when added after infection, with IC(50) 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 CVB(3)-infected cells, especially in the 0.3 and 0.5 g/kg/day treatment groups. Furthermore, the CVB(3)-infected mice were treated with the extract solution with dosages of 0.3 g/kg/day beginning 24 h post-CVB(3) 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-CVB(3) activity in vitro and in vivo and thus provides a re-evaluation of this old remedy with a broad therapeutic potential.
PMID: 22809033 DOI: 10.1142/S0192415X12500607 Am J Chin Med. 2012;40(4):801-12. doi: 10.1142/S0192415X12500607. ncbi.nlm.nih.gov

Anti-metastatic effects of Rheum Palmatum L. extract in human MDA-MB-231 breast cancer cells.
Nho KJ, Chun JM, Lee AY, Kim HK.
Abstract
Rheum palmatum L. (RP) has been widely used in traditional medicine for the treatment of various diseases in Asian countries. The molecular mechanism of its anti-metastasis effect remains elusive. The present study assessed the effect of RP ethanol extract (RPE) on the highly metastatic human MDA-MB-231 breast cancer cells in vitro. At a non-toxic concentration, RPE inhibited migration, motility and invasion in a concentration-dependent manner. To investigate the mechanisms involved, real-time PCR and Western blot analyses were performed. Results showed that RPE down-regulated the levels of extracellular matrix degradation-associated proteins, including MMP-2/-9, uPA and uPAR, and up-regulated PAI-1. In addition, RPE affected NF-?B by degrading IkBa, and affected the mitogen-activated protein kinase signal transduction pathway by depressing the activation of p38, ERK and Akt. These results suggest that RPE has potential anti-metastatic activity and warrants further investigation.
PMID: 26056975 DOI: 10.1016/j.etap.2015.05.006 Environ Toxicol Pharmacol. 2015 Jul;40(1):30-8. doi: 10.1016/j.etap.2015.05.006. Epub 2015 May 16. ncbi.nlm.nih.gov

The Effects of Rheum Tanguticum Polysaccharide on the Polarization of Th1 and Th2 Cells in TNBS-Induced Colitis in Murine.
Liu L, Mei QB, Wang ZP, Zhou YM, Zhang H, Long Y, Liu JY.
Abstract
Inflammatory bowel diseases (IBDs) are chronic inflammatory intestinal disorders that are characterized by thickened colon walls, colon ulcerations, including two forms of ulcerative colitis (UC) and Crohn's disease (CD). UC and CD share some similar clinico-pathological characteristics but their causes are opposite. The imbalance in cytokinesis produced by Th1 and Th2 cells, the subunit of CD4(+) T cells, plays a key role in the development of IBDs. Although traditional treatment for IBDs is effective to some patients, it has numerous adverse-effects such as immuno-depression. In our previous study we found some therapeutic effects of Rheum tanguticum polysaccharide (RTP) on CD. Our present investigation focuses on the comparison of the effects of RTP (200 mg·kg(-1), once a day for five days) on UC induced by trinitrobenzene sulfonic acid (TNBS)/ethanol in BALB/c mice and CD induced by TNBS in SD rats. The mechanism of RTP was investigated by using immuno-histochemistry, Elisa assay, flow cytometry and western-blot analysis. Our results showed that RTP had significant therapeutic effects on both UC and CD. The ulcerative index and colon weight were significantly attenuated after RTP treatment while MPO activity in RTP-treated animals was markedly lower than that in the animals of TNBS administration (P<0.05, P<0.01). RTP also showed significant inhibitory effects on the expansion of CD4+T cells simultaneously improving the imbalance of Th1 and Th2 polarization (P<0.01). In conclusion, RTP appears to poses all the pre-requisites to be applied in therapeutic intervention, thus, offering a hope for effective treatment for IBDs.
PMID: 23674951 PMCID: PMC3614577 Int J Biomed Sci. 2005 Jun;1(1):23-32. ncbi.nlm.nih.gov

The beneficial effect of Rheum tanguticum polysaccharide on protecting against diarrhea, colonic inflammation and ulceration in rats with TNBS-induced colitis: the role of macrophage mannose receptor in inflammation and immune response.
Liu L, Guo Z, Lv Z, Sun Y, Cao W, Zhang R, Liu Z, Li C, Cao S, Mei Q.
Abstract
Rhubarb has been used as a folk remedy for gastrointestinal disease in China for over two thousand years. In the present study, we evaluated the effect of Rheum tanguticum polysaccharide (RTP), a water soluble fraction extracted from rhubarb, on protection from inflammation and colonic damage in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. RTP protected against diarrhea, colon weight increase, and ulceration induced by TNBS. It was at least as effective as dexamethasone (DEX). RTP significantly decreased myeloperoxidase (MPO) activity in the colonic mucosa. Oral administration of RTP was as effective as intraperitoneal (i.p.) injection on toxicity protection and MPO activity. To further investigate the possible underlying mechanism, we studied the role of mannose receptor (MR) in cytokine secretion, ligand binding and endocytosis of macrophages. The secretion of IFN-gamma was dramatically increased while IL-4 decreased in colitis compared to the control (normal rats), and RTP restored the condition similar to the control in vivo. The secretion of IFN-gamma by macrophages was induced by RTP and lipoarabinomannan (LAM) but not mannose in vitro. Mannose completely inhibited the effect of RTP, while RTP and LAM affected each other on IFN-gamma secretion. The MR-mediated ligand binding and endocytosis of macrophages were markedly decreased in colitis and RTP restored their function to near normal condition. The results indicated that RTP targeted MR and down-regulation of Th1-polarized immune response may be the possible mechanism for its attenuation of intestinal inflammation and damage. RTP may be useful for treatment of patients with inflammatory bowel disease.
PMID: 18790466 DOI: 10.1016/j.intimp.2008.04.013 Int Immunopharmacol. 2008 Nov;8(11):1481-92. doi: 10.1016/j.intimp.2008.04.013. Epub 2008 May 28. ncbi.nlm.nih.gov

Anti-proliferative effects of estrogen receptor-modulating compounds isolated from Rheum palmatum.
Kang SC1, Lee CM, Choung ES, Bak JP, Bae JJ, Yoo HS, Kwak JH, Zee OP.
Abstract
The Rheum palmatum L., a traditional medicine in Korea, was screened for their estrogenic activity in a recombinant yeast system with a human estrogen receptor (ER) expression plasmid and a reporter plasmid used in a previous study. The EC50 values of the n-hexane, dichloromethane, ethyl acetate, n-butanol, and water fractions of the methanolic extract of R. palmatum in the yeast-based estrogenicity assay system were 0.145, 0.093, 0.125, 1.459, 2.853 microg/mL, respectively, with marked estrogenic activity in the dichloromethane fraction. Using an activity-guided fractionation approach, five known anthraquinones, chrysophanol (1), physcion (2), emodin (3), aloe-emodin (4) and rhein (5), were isolated from the dichloromethane fraction. Compound 3 had the highest estrogenic relative potency (RP, 17bestradiol = 1.00) (6.3 x 10(-2)), followed by compound 4 (3.8 x 10(-3)), compound 5 (2.6 x 10(-4)), a compound 1 (2.1 x 10(-4)). Also, compound 3 and fraction 3 (which contained compound 3) of the dichloromethane fraction of R. palmatum showed strong cytotoxicity in both ER-positive (MCF-7) and-negative (MDA-MB-231) breast cancer cell lines.
PMID: 18563353 DOI: 10.1007/s12272-001-1218-1 Arch Pharm Res. 2008 Jun;31(6):722-6. doi: 10.1007/s12272-001-1218-1. Epub 2008 Jun 19. ncbi.nlm.nih.gov

Combined Therapy with Rheum tanguticum Polysaccharide and Low-dose 5-ASA Ameliorates TNBS-Induced Colitis in Rats by Suppression of NF-?B.
Liu L, Liu Z, Zhang T, Shi L, Zhang W, Zhang Y.
Abstract
The most common conventional therapy for inflammatory bowel disease in clinical practice involves the use of nonsteroidal anti-inflammatory drugs, such as 5-amino salicylic acid. However, a high dose of 5-amino salicylic acid may bring about severe side effects. Chinese people have used Rheum tanguticum as a folk remedy for gastrointestinal disease for two thousand years. Our group has isolated R. tanguticum polysaccharide 1 from R. tanguticum and verified that it can attenuate 2,4,6-trinitrobenzene sulfonic acid-induced colitis in murines/rats. The present study aims to evaluate whether the addition of R. tanguticum polysaccharide 1 can improve efficacy and limit subsequent side effects of conventional treatment (5-amino salicylic acid) in rats with 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Sixty Sprague-Dawley male rats were randomized into five groups and treated with (1) saline (saline, 0.2?mL/day ×?5, p.?o.), (2) 2,4,6-trinitrobenzene sulfonic acid alone (saline, 0.2?mL/day ×?5, p.?o.), (3) 2,4,6-trinitrobenzene sulfonic acid +?5-amino salicylic acid (5-amino salicylic acid, 75?mg/kg/day ×?5, p.o), (4) 2,4,6-trinitrobenzene sulfonic acid + R. tanguticum polysaccharide 1 (R. tanguticum polysaccharide 1, 200?mg/kg/day ×?5, p.?o.), and (5) 2,4,6-trinitrobenzene sulfonic acid +?5-amino salicylic acid + R. tanguticum polysaccharide 1 (5-amino salicylic acid, 25?mg/kg/day ×?5, p.o; R. tanguticum polysaccharide 1, 200?mg/kg/day ×?5, p.?o.). All the rats were sacrificed on the 6th day after treatment using an overdose of anesthesia. A histological assessment was performed using semiquantitative scores; nuclear factor-kappa B and tumor necrosis factor-a were measured with Western blot, cyclooxygenase 1 and cyclooxygenase 2 protein expressions were investigated by RT-polymerase chain reaction, and prostoglandin E2 and inducible nitric oxide synthase productions were investigated by ELISA. The extent and severity of histological signs were attenuated significantly in the 2,4,6-trinitrobenzene sulfonic acid +?5-amino salicylic acid + R. tanguticum polysaccharide 1 group. Treatment with R. tanguticum polysaccharide 1 plus 5-amino salicylic acid markedly decreased nuclear factor-kappa Bp65 and tumor necrosis factor-a protein expressions. R. tanguticum polysaccharide 1 and 5-amino salicylic acid had no effect on cyclooxygenase 1 protein expression, but inhibited the overexpression of the cyclooxygenase 2 protein. After treatment with 5-amino salicylic acid and R. tanguticum polysaccharide 1, the prostoglandin E2 level increased significantly and the inducible nitric oxide synthase level decreased considerably in the 2,4,6-trinitrobenzene sulfonic acid +?5-amino salicylic acid + R. tanguticum polysaccharide 1 group compared with the 2,4,6-trinitrobenzene sulfonic acid alone group. These results demonstrate that combined therapy with R. tanguticum polysaccharide 1 and low-dose 5-amino salicylic acid had more favorable effects on 2,4,6-trinitrobenzene sulfonic acid-induced colitis in rats, and its effects may be associated with inhibiting nuclear factor-kappa Bp65 protein expression and tumor necrosis factor-a production, resulting in a decrease of cyclooxygenase 2 and inducible nitric oxide synthase protein expressions.
PMID: 26069953 DOI: 10.1055/s-0035-1545945
Planta Med. 2015 Jun;81(9):705-12. doi: 10.1055/s-0035-1545945. Epub 2015 Jun 12. ncbi.nlm.nih.gov

The effect of emodin, an anthraquinone derivative extracted from the roots of Rheum tanguticum, against herpes simplex virus in vitro and in vivo.
Xiong HR, Luo J, Hou W, Xiao H, Yang ZQ.
Abstract
AIM OF THE STUDY:
Herpes simplex viruses (HSV-1 and -2) are important pathogens for humans and the discovery of novel anti-HSV drugs with low toxicity deserves great efforts. Rhubarb is one of the oldest and best-known traditional Chinese medicines. We initiated this study to test if emodin is the active ingredients from Rheum tanguticum (R. tanguticum, one of the Chinese Rhubarb) against HSV infection and to investigate its antiviral activity on HSV infection in tissue culture cells and in a mouse model.
MATERIALS AND METHODS:
Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) was extracted and purified from R. tanguticum (cultivated at high mountainous area in Qinghai) and the purity was determined by high performance liquid chromatography. The antiviral experiments of emodin against HSV infection were performed in vitro and in vivo. In vivo, the HSV-infected mice were orally administered with emodin beginning at 24 h post-HSV exposures with dosages of 3.3 g/kg/day, 6.7 g/kg/day, and 11.3 g/kg/day, respectively, for 7 days.
RESULTS:
Emodin was found to inhibit the replication of HSV-1 and HSV-2 in cell culture at the concentration of 50 µg/ml with antiviral index of 2.07 and 3.53, respectively. The emodin treatment increased the survival rate of HSV-infected mice, prolonged survival time and showed higher efficacy of HSV elimination from brain, heart, liver and ganglion, compared to the viral controls. In addition, the antiviral activity of emodin was found to be equivalent to that of acyclovir in vivo.
CONCLUSIONS:
Our results indicate that emodin has the anti-HSV activity in vitro and in vivo and is thus a promising agent in the clinical therapy of HSV infection.
PMID: 21050882 DOI: 10.1016/j.jep.2010.10.059 J Ethnopharmacol. 2011 Jan 27;133(2):718-23. doi: 10.1016/j.jep.2010.10.059. Epub 2010 Nov 2. ncbi.nlm.nih.gov

Immunomodulation of Rheum tanguticum polysaccharide (RTP) on the immunosuppressive effects of dexamethasone (DEX) on the treatment of colitis in rats induced by 2,4,6-trinitrobenzene sulfonic acid.
Liu L, Yuan S, Long Y, Guo Z, Sun Y, Li Y, Niu Y, Li C, Mei Q.
Abstract
Dexamethasone (DEX) is still the main choice for colitis, although the immunosuppressive side effects are still the troublesome problems to overcome. In our previous study, Rheum tanguticum polysaccharide (RTP), extracted from traditional Chinese medicine rhubarb, targeted mannose receptor, showed immunoregulatory effect on the balance of Th1 and Th2 polarization in colitis rats. For the present study, we hypothesized that RTP could regulate the immunosuppressive effects of DEX. Taking advantage of the colon delivery ability of the polysaccharide, we prepared the double emulsion of RTP microsphere containing DEX to investigate the potential immunoregulatory effects of RTP on DEX immunosuppression in TNBS-induced colitis in rats. As expected, DEX-RTP microsphere showed not only significant immunomodulatory effects, but also strong anti-inflammation. The microsphere balanced enteric bacteria disorder, decreased TLR4 activation and promoted the balance of Th1 and Th2 polarization, inhibited NF-kappaB activity. Especially, DEX-RTP showed significant colon injury reparation. DEX alone exhibited a strong anti-inflammatory effect by suppressing MPO activity, down-regulate NF-kappaB activity and Th1 cytokines production. However, DEX showed severe immunosuppressive effects. It aggravated the intestinal commensal bacteria disorder, induced thymus atrophy and the further imbalance of Th1/Th1 cytokine polarization. RTP showed significant immunoregulatory effects. A significant protection on the intestinal bacterial balance, TLR4 and NF-kappaB activation decreased, and Th1/Th2 cytokine production balance were showed in RTP. In conclusion, DEX-RTP microsphere delivered DEX directly to the colon avoiding the absorption at the upper intestinal tract and showed synergistic effects on colitis both from the strong anti-inflammatory effects of DEX and from the immunoregulation of RTP.
PMID: 19788936 DOI: 10.1016/j.intimp.2009.09.013 Int Immunopharmacol. 2009 Dec;9(13-14):1568-77. doi: 10.1016/j.intimp.2009.09.013. Epub 2009 Sep 27. ncbi.nlm.nih.gov

Inhibition of endosomal fusion activity of influenza virus by Rheum tanguticum (da-huang).
Lin TJ, Lin CF, Chiu CH, Lee MC, Horng JT.
Abstract
Rhubarb (Rheum tanguticum; da-huang in Chinese medicine) is a herbal medicine that has been used widely for managing fever and removing toxicity. In this study, we investigated how rhubarb inhibits influenza virus during the early stage of the infectious cycle using different functional assays. A non-toxic ethanolic extract of rhubarb (Rex) inhibited several H1N1 subtypes of influenza A viruses in Madin-Darby canine kidney cells, including strains that are clinically resistant to oseltamivir. Time course analysis of Rex addition showed that viral entry was one of the steps that was inhibited by Rex. We also confirmed that Rex effectively inhibited viral attachment and penetration into the host cells. The inhibition of red blood cell haemolysis and cell-cell fusion by Rex suggests that Rex may block haemagglutinin-mediated fusion (virus-endosome fusion) during the fusion/uncoating step. Rex has the capacity to inhibit influenza viruses by blocking viral endocytosis. Thus, rhubarb might provide an alternative therapeutic approach when resistant viruses become more prevalent.
PMID: 27302738 PMCID: PMC4908592 DOI: 10.1038/srep27768 Sci Rep. 2016 Jun 15;6:27768. doi: 10.1038/srep27768. ncbi.nlm.nih.gov

Crude extract of Rheum palmatum L. Induces cell cycle arrest S phase and apoptosis through mitochondrial-dependent pathways in U-2 OS human osteosarcoma cells.
Lin CC, Lee MH, Lin JH, Lin ML, Chueh FS, Yu CC7 Lin JP, Chou YC, Hsu SC, Chung JG.
Abstract
Cancer is the second cause of death in children. Osteosarcoma is the most common primary malignancy of solid bone cancer primarily affecting adolescents and young adults. In the Chinese population, the crude extract of Rheum palmatum L. (CERP) has been used for treating different diseases, including SARS, rheumatoid arthritis, coxsackievirus B3, and human colon cancer cell, pancreatic cancer. There are no reports on CERP and human osteosarcoma cells. The present study examined effects of CERP on cytotoxicity including cell cycle distribution and cell death (apoptosis) in U-2 OS human osteosarcoma cells. CERP significantly induced S phase arrest in U-2 OS cells in a dose-dependent. CERP produced DNA damage and DNA condensation. Other effects of CERP were stimulation of ROS and Ca(2+) , mitochondria impairment, and activation of caspase-3, -8, and -9. CERP increased the levels of Bax, Bak, Bad, cyclin B, Fas, PARP, GRP78, GADD153, AIF, Endo G, Calpain-2, p21, and p27, but decreased the levels of Bcl-2, BCL-X, XIAP, Akt, CDC25A, CDK2, Cyclin A, and Cyclin E of U-2 OS cells. It was also observed that CERP promoted the expression of AIF, Endo G, GADD153, and cytochrome c. These results indicate that CERP has anticancer effects in vitro and provide the foundation for in vivo studies of animal models of osteosarcoma. Environ Toxicol 31: 957-969, 2016.
PMID: 25689151 DOI: 10.1002/tox.22105  Environ Toxicol. 2016 Aug;31(8):957-69. doi: 10.1002/tox.22105. Epub 2015 Feb 17. ncbi.nlm.nih.gov