Rhubarb Root Extract
Rhubarb (Rheum Officinale) is an ancient herb bestowed with a multitude of pharmacological activities. Rhubarb includes approximately 60 species of plants of the genus Rheum L. from the Polygonaceae family.
Rhubarb grows across Europe, North America, and part of Asia, and the species from different regions differ. Rhubarb has thick roots, hollow and erect stems, and small white-green or purple-red flowers clustered on the branches.1,2,3
Rhubarb root extracts have strong antibacterial, antioxidative, anti-inflammatory, and hemostatic effects, due to which it is used for constipation, chronic liver and kidney diseases, and skin lesions. The pharmaceutically relevant compounds in Rhubarb are sennosides, anthraquinones, stilbenes, glucose gallates, naphthalenes, and catechins.4,5,6
Rhubarb possesses antiviral activity against Herpes simplex viruses (HSV). The anthraquinones in Rhubarb are the constituents effective against HSV.6
As per a study by Hsiang et al., the extract of Rhubarb prevented the process of HSV attachment and penetration. Wang et al. reported that the antiviral activity of Rhubarb against HSV was comparable to acyclovir in vivo.7
A study by Shen et al. demonstrated the antiviral activity of Rhubarb (R. tanguticum) nanoparticles against HSV-1. The study showed that Rhubarb nanoparticles could inhibit HSV-1 infection by interfering with multiple steps of the viral life cycle, including attachment, entry, and replication. The study that incorporated virus inactivation assay showed that treatment of high concentration (350 µg/ml) of Rhubarb nanoparticles inhibits viral plaque formation by nearly 50%. Rhubarb R. nanoparticles probably interacted with cell-free virions, which resulted in the suppression of viral infection.8
Apart from antiviral activity, Rhubarb has strong antibacterial activity and a wide antibacterial spectrum. Rhubarb can also reverse bacterial resistance to antibiotics by inhibiting the formation of bacterial biofilms.1
Rhubarb has efficient antibacterial activities against a wide spectrum of bacteria, including Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Helicobacter pylori, Escherichia coli, bifidobacteria, Lactobacillus and multidrug-resistant Helicobacter pylori.9,10
Exploring the anti-inflammatory effects of Rhubarb has been the subject of many research studies. Kolodziejczyk-Czepas et al. reviewed the anti-inflammatory effects of Rhubarb components rhaponticin and the aglycone rhapontigenin. The anti-inflammatory effects were found to be due to the inhibition of enzymes cyclooxygenase and lipoxygenase and activation of hyaluronoglucosaminidase. Apart from rhaponticin, other Rhubarb components that have anti-inflammatory effects include emodin, rhein, chrysophanol, and aloe-emodin.1,11
Rhubarb is also popular for its wound healing properties. A study by Tang et al. evaluated the wound healing capacity of emodin, a component of Rhubarb. Emodin is an anthraquinone derivative from the roots of Rhubarb. The study found that topically applied emodin enhanced the repair of rats’ excisional wounds. The results showed that emodin promoted the repair of rats’ excisional wounds via a complex mechanism involving stimulation of tissue regeneration and regulating the TGF-beta(1) signaling pathway.12
Exposure to ultraviolet (UV) radiation is a well-known reason for skin damage, such as inflammation, premature aging, and photodamage. UV radiation can stimulate the generation of reactive oxygen species, produce proinflammatory cytokines (cytokines that favor inflammation) and melanocyte-stimulating hormone (which protects the skin from UV rays). UV rays also increase tyrosinase activity, which increases melanin synthesis.13
Rhubarb (Rheum rhaponticum) extract can modulate damage induced by UV radiation. Rhubarb extract acts through multiple mechanisms, including antioxidant and radical scavenging properties, inhibition of tyrosinase and tyrosine kinase activities, and interleukin 1, TNF-α, and melanocyte-stimulating hormone production in human melanocytes subjected to UV stimulation. These results support the use of Rhubarb in skin-lightening products and cosmetic, sunscreen, and skincare products for the prevention or reduction of photodamage.13
- Xiang H, Zuo J, Guo F, et al. What we already know about rhubarb: a comprehensive review. Chin Med. 2020;15:88.
- Lee MR, Hutcheon J, Dukan E, et al. Rhubarb (Rheumspecies): the role of Edinburgh in its cultivation and development. J R Coll Phys Edinburgh. 2017;47(1):102–109.
- Cao YJ, Pu ZJ, Tang YP, et al. Advances in bio-active constituents, pharmacology and clinical applications of rhubarb. Chin Med. 2017;12(1):36–47.
- Tsai KH, Hsien HH, Chen LM, et al. Rhubarb inhibits hepatocellular carcinoma cell metastasis via GSK-3-β activation to enhance protein degradation and attenuate nuclear translocation of β-catenin. Food Chem. 2013;138(1):278–285.
- Shedoeva A, Leavesley D, Upton Z, et al. Wound Healing and the Use of Medicinal Plants. Evid Based Complement Alternat Med. 2019;2019:2684108.
- Xiong HR, Luo J, Hou W, 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;133(2):718-723.
- Hsiang CY, Hsieh CL, Wu SL, et al. Inhibitory effect of anti-pyretic and anti-inflammatory herbs on herpes simplex virus replication. Am J Chin Med. 2001;29(3-4):459-467.
- Wang ZY, Xu B, Song YY, et al. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi. 2003;17(2):169-173.
- Wang J, Zhao H, Kong W, et al. Microcalorimetric assay on the antimicrobial property of five hydroxyanthraquinone derivatives in rhubarb (Rheum palmatum) to Bifidobacterium adolescentis. Phytomedicine. 2010;17(8):684–689.
- Nanasombat S, Kuncharoen N, Ritcharoon B, et al. Antibacterial Activity of Thai medicinal plant extracts against oral and gastrointestinal pathogenic bacteria and prebiotic effect on the growth of Lactobacillus acidophilus. Chiang Mai J Sci. 2018;45(1):33–44.
- Kolodziejczyk-Czepas J, Czepas J. Rhaponticin as an anti-inflammatory component of rhubarb: a minireview of the current state of the art and prospects for future research. Phytochem Rev. 2019;18(5):1375–1386.
- Tang T, Yin L, Yang J, et al. Emodin, an anthraquinone derivative from Rheum officinale Baill, enhances cutaneous wound healing in rats. Eur J Pharmacol. 2007;567(3):177-185.
- Silveira JP, Seito LN, Eberlin S, et al. Photoprotective and antioxidant effects of Rhubarb: inhibitory action on tyrosinase and tyrosine kinase activities and TNF-α, IL-1α and α-MSH production in human melanocytes. BMC Complement Altern Med. 2013;13:49.