Sophora flavescens

Sophora flavescens

Common Names

  • Ku Shen Gen
  • Bitter root
  • Yellow sophora root

For Patients & Caregivers

How It Works

Sophora flavescens has shown anticancer effects in lab studies, but has not been studied for cancer prevention or treatment in humans.

Sophora flavescens or Ku Shen, which in Chinese means “bitter root,” is an herb used in Traditional medicine to treat a wide variety of symptoms, with purported effects on the heart, liver, intestinal tract, and skin. Lab and animal studies have shown that some compounds can kill cancer cells and help fight certain viruses. However, human data are lacking.

Sophora flavescens may act like an estrogen in the body. Patients with hormone-sensitive cancer should avoid this product.

Purported Uses
  • Anticancer
    Lab studies show anticancer activities through different mechanisms. Despite positive lab results, this use has not been proven by clinical trials.
  • Anti-bacterial
    This claim is not supported by research.
  • Antiviral
    Limited evidence suggests that Sophora flavescens may be a useful treatment for hepatitis B and coxsackie B viruses, but more data are necessary to support this use.
  • Asthma
    A single non-randomized trial supports this use, but more data are needed.
  • Skin disorders
    Sophora flavescens is used to treat skin disorder in Traditional Medicine. But this use has not been proven in clinical trials.
Do Not Take If
  • You are taking paclitaxel: In animal studies, Sophora flavescens flavonoids increased the effects of Taxol against certain tumors.
  • You are taking ampicillin/gentamicin: In the lab, one of the compounds in Sophora flavescens increased the activity of these antibiotics against oral bacteria.
  • You have a hormone-sensitive cancer: Sophora flavescens has estrogenic effects and can stimulate the proliferation of hormone-sensitive cancer cells.
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For Healthcare Professionals

Brand Name
Ku shen, Sophora root
Scientific Name
Sophora flavescens
Clinical Summary

Sophora flavescens is a deciduous shrub related to peas. The root known as “Ku Shen” which means “bitter root” in Chinese, has been used in Traditional Medicine for two thousand years to treat a variety of conditions, including diarrhea, jaundice, skin rashes, and to kill parasites (1). Although this herb is generally not consumed as a dietary supplement in the West, recent lab studies indicate that it has antitumor properties and patients are using it as a natural cancer treatment.

Matrine, an alkaloid present in Sophora flavescens, demonstrated antitumor effects against liver (10) (18), breast (19), pancreas (20), myeloma (21) and gastric (22) (23) cancer cell lines. Other flavonoids such as kuraninone and sophoraflavonone are thought to be biologically active as well and may have vasodilatory and antiviral effects (5) (6) (7). However, large-scale clinical studies are needed at confirm these effects in humans.

Sophora flavescens acts as a phytoestrogen (24) (25) (26). Patients with hormone-sensitive cancers should avoid this product.

Purported Uses
  • Cancer treatment
  • Cardiovascular disease
  • Asthma
  • Arrhythmia
Mechanism of Action

In animal models, the antiviral properties of sophoridine, an alkaloid constituent, appear to be mediated via upregulation of IL-10 and IFN-gamma cytokines (11). S. flavescens flavonoids may promote vasodilation by inhibiting Ca2+ influx through a voltage-gated channel (12). The flavonoids sophoraflavonone G and kurarinone appear to be responsible for antioxidant effects, which are mediated through free-radical scavenging (4). Anti-inflammatory effects of Sophoraflavonone G are attributed to the inhibition of prostaglandin E2 formation via COX-2 downregulation (13). (2S)-2’-Methoxykurarinone, a compound isolated from the S. flavescens root, inhibits osteoclast differentiation and bone resorption via receptor activator of nuclear factor-κB ligand (RANKL)-induced mitogen-activated protein kinases (MAPKs) and c-Fos-NFATc1 signaling pathways (29).

Most of the reported antineoplastic effects of S.flavescens are due to the proapoptotic activity of matrine, the main alkaloid constituent. In human hepatocellular carcinoma cells, matrine inhibits matrix metalloproteinase-9 (MMP-9) by downregulating the NF-kappa B pathway (18). It also demonstrates antiangiogenic effects by inhibiting VEGF and VEGFR-2 (19). Matrine triggers the mitochondrial pathway, in which cytochrome C release induces caspase-9 and -3 activation and subsequently induces apoptosis (2) (3) (10) (21).

  • Patients with hormone-sensitive cancers should avoid taking S. flavescens as it demonstrated estrogenic effects in vitro (24) (25) (26), and can stimulate the proliferation of hormone-sensitive cancer cells.
Adverse Reactions
  • Two constituents of S. flavescens, kurarinone and sophoraflavanone G, have hepatotoxic effects in animal studies (30).
Herb-Drug Interactions
  • Paclitaxel: In mice, S. flavescens flavonoids may enhance the effects of Taxol against certain tumors (16).
  • Ampicillin/gentamicin: In vitro, sophoraflavanone G may increase the activity of these antibiotics against oral bacteria (17).
  1. Chen JK and Chen TT. Chinese Medical Herbology and Pharmacology. First ed. 2004, City of Industry, CA: Art of Medicine Press, Inc.

  2. Jiang H, Hou C, Zhang S, et al. Matrine upregulates the cell cycle protein E2F-1 and triggers apoptosis via the mitochondrial pathway in K562 cells. Eur J Pharmacol. 2007 Mar 22;559(2-3):98-108.

  3. Piao XL, et al. Identification and characterization of antioxidants from Sophora flavescens. Biol Pharm Bull. 2006;9(9): 1911-5.

  4. Hoang BX, et al. New approach in asthma treatment using excitatory modulator. Phytotherapy research. 2007;21(6): p. 554-7.

  5. Chen SX, et al. [Therapeutic effect of kangke injection on viral myocarditis and its anticoxsackie virus mechanism]. Zhong Guo Zhong Xi Yi Jie He Za Zhi. 1997. 17(4): p. 207-9.

  6. Lee JH, et al. A new cytotoxic prenylated chalcone from Sophora flavescens. Arch Pharm Res. 2007;30(4): 408-11.

  7. Yamahara J, et al. Vasodilatory active principles of Sophora flavescens root.J Ethnopharmacol. 1990;29(1): p. 79-85.

  8. Sun M, et al. Novel antitumor activities of Kushen flavonoids in vitro and in vivo. Phytother Res. 2007;21(3): 269-77.

  9. Cha JD, et al. Antibacterial activity of sophoraflavanone G isolated from the roots of Sophora flavescens. J Microbiol Biotechnol. 2007;17(5): 858-64.

  10. Yu HB, Zhang HF, Li DY, et al. Matrine inhibits matrix metalloproteinase-9 expression and invasion of human hepatocellular carcinoma cells. J Asian Nat Prod Res. 2011 Mar;13(3):242-50.

  11. Li H, Tan G, Jiang X, et al. Therapeutic effects of matrine on primary and metastatic breast cancer. Am J Chin Med. 2010;38(6):1115-30.

  12. Liu T, Song Y, Chen H, Pan S, Sun X. Matrine inhibits proliferation and induces apoptosis of pancreatic cancer cells in vitro and in vivo. Biol Pharm Bull. 2010;33(10):1740-5.

  13. Han Y, Zhang S, Wu J, et al. Matrine induces apoptosis of human multiple myeloma cells via activation of the mitochondrial pathway. Leuk Lymphoma. 2010 Jul;51(7):1337-46.

  14. Dai ZJ, Gao J, Ji ZZ, et al. Matrine induces apoptosis in gastric carcinoma cells via alteration of Fas/FasL and activation of caspase-3. J Ethnopharmacol. 2009 May 4;123(1):91-6.

  15. Kang SC, Lee CM, Choi H, et al. Evaluation of oriental medicinal herbs for estrogenic and antiproliferative activities. Phytother Res. 2006 Nov;20(11):1017-9.

  16. De Naeyer A, Vanden Berghe W, Pocock V, et al. Estrogenic and anticarcinogenic properties of kurarinone, a lavandulyl flavanone from the roots of Sophora flavescens. J Nat Prod. 2004 Nov;67(11):1829-32.

  17. Yoo HH, Kim T, Ahn S, et al. Evaluation of the estrogenic activity of Leguminosae plants. Biol Pharm Bull. 2005 Mar;28(3):538-40.

  18. Shen CC, Lin TW, Huang YL, et al. Phenolic constituents of the roots of Sophora flavescens. J Nat Prod. 2006 Aug;69(8):1237-40.

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