Japanese alnus – proven benefits, uses


The scientific name of Japanese alnus is Alnus japonica Steud.


Scientific names Common names
Alnus harinoki Siebold Arnus (If.)
Alnus japonica (Thunb.) Steud. Japanese alder (Engl.)
Alnus reginosa Nakai Japanese alnus (Engl.)
Betula japonica Thunb.
Alnus japonica (Thunb.) Steud. is an accepted name
Other vernacular names
CHINESE: Ri ben qi mu.
JAPANESE: Han no ki.

Arnus is a small- to medium-sized deciduous tree growing to a height of 15 meters. Leaves are alternate, narrow-elliptic, acuminate, wedge-shaped at the base, up to 12 centimeters long, glossy and dark green above and pale underneath, the margins slightly toothed. Flowers are staminate, in long catkins; the pistillate flowers are in short catkins, becoming woody cones with 5-lobed scales.


– Indigenous to Korea.

– Propagated by seed or grafting.


– Two diarylheptanoids, oregonin and hirsutanone were isolated by bioassay-guided fractionation of the methanol extracts of the leaves of Alnus japonica Steud and their structures were elucidated from their spectroscopic data. Compounds exhibited significant low-density lipoprotein (LDL)-antioxidant activities.


– Studies suggest antioxidant, hepatoprotective, cytotoxic, anticancer, antiatherosclerotic properties.

arnusParts used

Stem bark, leaves.

Folkloric medicine remedies, benefits and uses of arnus

– Popular folk medicine in Korea, used for cancer, gastric disorders, hepatitis and fatty liver.

– Various species of alder, including this species, seem to contain antitumor compounds.

– In Oriental medicine, bark used for fever, hemorrhage, gastroenteric disorders, lymphatic disease and cancers. (see study)

Other uses

– Dye is obtained from the bark.

– Wood – close grained; used for turnery, charcoal.

Scientific studies about arnus health benefits and uses

Hepatoprotective / protect liver /Antioxidant:

Alnus japonica showed antioxidant activity and hepatoprotective effects against acetaminophen-induced cytotoxicity in cultured hepatocytes in vitro.

Cytotoxic / Diarylheptanoids:

Study isolated 10 compounds from the bark of Alnus japonica. The diarylheptanoids showed potent cytotoxic activities against murine B16 melanoma cells and human SNU-C1 gastric cancer cell line.

Anti-Influenza / Diarylheptanoids:

Study isolated two rare acylated diarylheptanoids from the bark of A japonica – oregonoyl A and oregonoyl B, with nine known compounds. Platyphyllone, was strongly active, and platyphyllonol-5-xylopyranoside was moderately active on antiviral testing, compared with positive control, zanamivir.

Anti-Atherosclerosis / Diarylheptanoids:

Study isolated reported the inhibitory effects of two diarylheptanoids from the methanolic extracts of Alnus japonica leaves on the expression of adhesion molecules in human umbilical vein endothelial cells. Results suggest the compounds may be useful in prevention and treatment of atherosclerosis.


Study isolated naturally occurring bioactive compounds from AJ that showed significant radical-scavenging antioxidant activity in a concentration-dependent manner.

Antioxidant / Anti-LDL Oxidation / Anti-Inflammatory:

Study isolated 5-O-methylhirsutanonol (5-MH) from the leaves of A japonica which exhibited antioxidant activities on Cu2+ and AAPH-mediated LDL oxidation and well as macrophage-mediated LDL oxidation. 5-MH also suppressed the expression of inflammation-associated genes, such as tumor necrosis factor alpha, COX-2 and IL-1ß.

Hirsutenone / Atopic Dermatitis:

Study isolated hirsutenone from the bark of Alnus japonica. Results showed hirsutenone may specifically inhibit calcium-activated processes in both T cells and mast cells and presents a potential for a new topical drug for atopic dermatitis, probably through a calcineurin inhibitor-mimicking mechanism.

Anti-Influenza Component / Bark:

Study of bark isolated four lupane-type triterpenes (1-4) and one steroid (5). Compound 3, betulinic aldehyde, exhibited a particularly strong anti-influenza effect against KBNP-0028 relative to a positive control.

Oregonin / I/R Induced Mesentery Oxidative Stress / Inhibition of NADPH Oxidase Activation/ Bark:

Study suggests that ORG restrained I/R-induced ROS production might be correlated to its inhibitive effect on NADPH activation.

Diarylheptanoids / Inhibition of Papain-Like Protease of SARS:

The papain-like protease, which controls replication of the acute respiratory syndrome coronavirus is identified as the potential drug target for the treatment of SARS. Of the nine diarylheptanoids isolated from Alnus japonica, hirsutenone (compound 2) showed the most potent PL inhibitory effect.

Atopic Dermatitis:

Study evaluated the immunomodulatory effect of A. japonica in a model of atopic dermatitis in NC/Nga mice. Leaf and bark extract suppressed the development of AD-like skin lesions, with decrease in blood eosinophils and decrease in serum IgE and Th2-related cytokine levels. Results suggest the leaf and bark extract may prove useful in the treatment of atopic dermatitis and other allergic skin diseases.

Cytotoxicity / Oregonin and Hirsutanone:

Study evaluated the cytotoxic effects of four different extracts from A. japonica on Caco-2 cells using MTT assay. The water extract showed highest cytotoxicity results. The 70% methanol extract showed highest content for both oregonin and hirsutanone.

Anticancer / Antioxidant / Caspase-Dependent Pathway:

Study evaluated A. japonica extracts for in vitro antioxidant and anticancer effects in AGS human gastric carcinoma cell lines. Results showed ethanol extracts have greater antioxidant activity than water extracts. The ethanol extract inhibited cell growth and induced cell death by increasing reactive oxygen species production in AGS cells. The extract triggered apoptosis when caspase-8, 7, 3 and PARP were activated. Results suggest a potential strategy for clinical chemotherapy.

Dyeing Properties / Bark and Heartwood:

Study evaluated the dyeing properties of cotton and silk fabrics dyed with A. japonica bark and heartwood extracts. Results showed tannin to be the major colorant component. Silk dye intake was better than that of cotton. Although washing fastness was not good, light, dry cleaning, and perspiration fastness were moderate. Also, rubbing fastness was moderately good grade. Dyed fabrics showed very good antimicrobial abilities of 99.9% against S. aureus and K. pneumonia.




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