Rhamnus nakaharai

Rhamnus Nakaharai is a herb that has been used as folk medicine in Taiwan for intestinal distress (mostly constipation) and asthma, it is a good source of Quercetin glycosides but not much research exists on the herb per se.

Our evidence-based analysis features 5 unique references to scientific papers.

Research analysis by and verified by the Examine.com Research Team. Last updated on Jun 14, 2018.

Summary of Rhamnus nakaharai

Primary Information, Benefits, Effects, and Important Facts

Rhamnus Nakaharai is a taiwanese medicine historically used for gastrointestinal ailments. It belongs to the Rhamnus species of plants of which variations are grown globally. Rhamnus Nakaharai is a source of various phytonutrients (plant based nutrients) particularly, it is a fairly good source of Quercetin.

How to Take

Recommended dosage, active amounts, other details

Not enough information is known about Rhamnus Nakaharai to come to a conclusion on proper dosages.

1Sources and composition

1.1. Sources and History

Rhamnus Nakaharia (from the family Rhamnaceae) is a folk medicine originating in Taiwan that has been used to treat constipation, inflammation, malignant tumors, and asthma.[1]

1.2. Composition

Rhamnus Nakaharai (RN) is a Taiwanese herbal medicine that contains:

  • The napthalenic compound 6-methoxysorigenin and various glycosides and acylates of the parent compound, such as alpha-sorinin[1] although 6-methoxyorigenin appears to be isolated from the wood component of the herb[1]

  • Isotorachyrsone and derivatives.[2][3]

  • Quercetin glycosides, specifically 3-O-Methylquercetin.[2][4]

2Interactions with Oxidation

The compound 6-methoxyorigenin appears to have anti-oxidative effects in vitro,[1] as well as the related compound Isotorachrysone, which share structural similarities.[3] 6-methoxygenin outperformed Trolox (a research standard) on Metal-chelating and protecting from lipid peroxidation, and was slightly outperformed on a DPPH test.[1] The IC50 of the metal chelating ability of 6-methoxyorigenin (615.90+/-5.79) was lesser than that of EDTA (127.92+/-6.27).[1]

3Inflammation and Immunology

3.1. Mechanisms

3-O-Methylquercetin has been found to suppress the inflammatory (Nitric Oxide mediated) response from LPS (research pro-inflammatory agent) in macrophages in vitro.[4] 3-O-Methylquercetin was found to inhibit Nitric Oxide release, protein expression of iNOS (induced by inflammation) and mRNA translation of iNOS with IC50 values of 4.23uM, 4.36uM, and 6.53uM respectively.[4]

4Intestinal Interactions

4.1. Mechanisms

3-O-Methylquercetin appears to be a selective PDE3 inhibitor with an IC50 of 1.6mM via competitive inhibition.[5]

Scientific Support & Reference Citations


  1. Ng LT, Lin CC, Lu CM. Antioxidative effects of 6-methoxysorigenin and its derivatives from Rhamnus nakaharai. Chem Pharm Bull (Tokyo). (2007)
  2. Lin CN, et al. Novel antiplatelet naphthalene from Rhamnus nakaharai. J Nat Prod. (1995)
  3. Hsiao G, et al. Antioxidant properties of isotorachrysone isolated from Rhamnus nakaharai. Biochim Biophys Acta. (1996)
  4. Jiang JS, et al. Mechanisms of suppression of nitric oxide production by 3-O-methylquercetin in RAW 264.7 cells. J Ethnopharmacol. (2006)
  5. Ko WC, et al. 3-O-methylquercetin more selectively inhibits phosphodiesterase subtype 3. Planta Med. (2003)

(Common misspellings for Rhamnus nakaharai include ramnus, rhamus, rhamnis, rhamis, ramnis, nakahara, nakahari)

Cite this page

"Rhamnus nakaharai," Examine.com, published on 30 September 2013, last updated on 14 June 2018, https://examine.com/supplements/rhamnus-nakaharai/