Rhubarb root is one of the most widely used herbs for constipation or pain-related diseases in natural medicine practice. The earliest records of using rhubarb for medicinal purposes date back to 2700BC in China. The roots contain tannins (e.g. rheum tannic acid, glucogallin, catechin, etc.) and anthraquinones such as emodin and rhein.
Literature showed that emodin had an inhibitory effect on the pathogenicity of Trichomonas vaginalis thus delayed the development of subcutaneous abscesses due to infection of this parasite in mice 1. In addition, Emodin had the anti-herpes simplex virus in vitro and in vivo 2, 3. Emodin promoted repair of rats’ excisional wounds via a complex mechanism involving stimulation of tissue regeneration and regulating Smads-mediated transforming growth factor-β1 signaling pathway 4. Through inhibiting the 5-lipoxygenase-catalysed leukotriene production, emodin might contribute to rhubarb’s inhibitory action of experimental atopic dermatitis 5.
It is well known that neuropathic pain is the most difficult type of pain to cure. The P2X(2/3) receptors in primary sensory neurons play a crucial role in facilitating the transmission of pain at neuropathic pain states. Gao et al demonstrated that emodin alleviated chronic neuropathic pain by inhibiting the transmission of neuropathic pain mediated by P2X(2/3) receptor of primary sensory neurons 6. The neuroprotection effect of rhubarb may result from the ability of emodin to decrease glutamate excitotoxicity via the activation of adenosine A1 receptors in rat hippocampal CA1 area 7.
Rhei has anti-inflammatory, antimicrobial and hemostatic properties 8,9,10. Rhei enhanced the antibacterial activity of ampicillin against methicillin-resistant Staphylococcus aureus (MRSA) 11.
Rhizoma Rhei (Rhubarb root) is one of the active ingredients in the Unitech Medical® CamWell™ Herb to Soothe™ botanical cream.
References
- Wang HH. Antitrichomonal action of emodin in mice. J Ethnopharmacol. 1993 Oct; 40(2):111-6.
- Wang ZY, et al. Inhibition effects of rhubarb ethanol extract on herpes simplex virus infection in vivo. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi. 2003 June;17(2):169-73.
- Xiong HR, et al. The effect of emodin, an anthraquinone derivative extracted from the roots of Rheum tanguticum against herpes simplex virus in vitro and in vivo. J Ethnopharmacol. 2011 Jan 27; 133(2):718-23.
- Tang T, et al. Emodin, an anthraquinone derivative from Rheum officinale Baill, enhances cutaneous wound healing in rats. Eur J Pharmacol. 2007 Jul 19;567(3):177-85.
- Jin JH, et al. Inhibition of experimental atopic dermatitis by rhubarb (rhizomes of Rheum tanguticum) and 5-lipoxygenase inhibition of its major constituent, emodin. Phytother res. 2011 May;25(5):755-9.
- Gao Y,et al. Effect of emodin on neuropathic pain transmission mediated by P2X2/3 receptor of primary sensory neurons. Brain Res Bull. 2011 Apr 5;84(6):406-13.
- Gu JW, et al. Effects of amodin on synaptic transmission in rat hippocampal CA1 pyramidal neurons in vitro. Neuropharmacology. 2005 Jul;49(10:103-11.
- Cuellar MJ,et al. Topical anti-inflammatory activity of some Asian medicinal plants used in dermatological disorders. Fitoterapia. 2001;72:221-229.
- Ding Y, et al. Exploration of emodin to treat alpha-naphthylisothiocyanate-induced cholestatic hepatitis via anti-inflammatory pathway. Eur j Pharmacol. 2008;590:377-386.
- WHO: Monographs on selected medicinal plants. World Health Organization, Geneva. 1999;231-240.
- Joung DK, et al. Synergistic effect of rhein in combination with ampicillin or oxacillin against methicillin-resistant Staphylococcus aureus. Exp Ther Med. 2012 April;3(4):608-612.