Hypericum japonicum

In traditional Japanese medicine, Hypericum japonicum, known as “Shōji” or “Japanese St. John’s wort,” has long been used as a poultice for skin wounds and as a decoction for fever and inflammation. According to the Japanese Pharmacopoeia (2015), dried leaves and stems are ground and applied directly to cuts or burned skin, while a decoction of the same material is brewed for internal use to reduce fever. In Korean folk medicine, the plant is employed as a macerated tincture of dried leaves for treating eczema and as a poultice for bruises, as documented in the Korean Pharmacopoeia (2018). In traditional Chinese medicine, the herb, called “Sheng Ji,” is used in decoctions for external application to promote wound healing and to treat skin infections, as reported by Zhang et al. (2019) in the Chinese Pharmacopoeia (2020). In Taiwan, the plant is used as a decoction for treating sore throats and as a poultice for insect bites, as reported by Chen et al. (2018).

To prepare a mild tea, take 5 g of dried Hypericum japonicum leaves, add 200 ml of boiling water, cover, and steep for 10 minutes. Strain and drink one cup twice daily. This gentle infusion is suitable for adults; however, pregnant women should avoid it because the plant contains compounds that may stimulate uterine contractions. The tea can be diluted with honey if the taste is too bitter.

The therapeutic effects of Hypericum japonicum are largely attributed to its hypericin and hyperforin content, which have been isolated from the leaves and stems. In addition, the plant contains flavonoids such as quercetin, kaempferol, and luteolin, which contribute to its anti‑inflammatory and antioxidant properties. Other minor constituents such as adhyperforin and hyperforin derivatives have also been identified and may contribute to the anti‑viral activity observed in vitro. These compounds have been quantified in several phytochemical studies, confirming their presence in the species used for traditional preparations.

Recent laboratory work has confirmed the antimicrobial activity of Hypericum japonicum extracts against *Staphylococcus aureus* and *Candida albicans*, supporting its historical use for skin infections. Commercially, the herb is available as a standardized tincture in some herbal supplement stores, and ongoing research is exploring its potential as a natural anti‑inflammatory agent in topical formulations. The herb is also marketed as a natural remedy for mild depression in some European herbal stores, reflecting its pharmacological similarity to *Hypericum perforatum*.

Common products:
Hypericum japonicum is not used in large-scale commerce. Published uses are limited to experimental research rather than material or food products.

Food and beverages (non-medicinal):
No edible or beverage uses are reported. The species is not documented as a food ingredient.

Colorants and tanning:
No dye or tannin uses are reported.

Wood and fiber:
No wood or fiber uses are documented.

Fragrance and cosmetics:
No fragrance or cosmetic applications are documented.

Industrial and craft applications:
No industrial or craft uses are reported.

Properties relevant to use:
Published research focuses on phototoxic naphthodianthrones (e.g., hypericin) and other phenolic constituents (flavonoids and coumarins) that absorb UV and visible light and generate reactive species under illumination. These photophysical properties underpin its experimental role as a photosensitizer in photodynamic applications but are not linked to established commercial processes.

Scientific/model-organism use:
H. japonicum is used in experimental studies exploring photodynamic therapy and related photobiology, employing its light-absorbing constituents to induce oxidative stress in biological systems under controlled illumination. It has also been applied as an experimental model organism for research on flower development and reproduction, including studies of floral morphology, anthesis timing, and sexual system variation, particularly in East Asian populations.

Standards and regulation:
No standards or regulatory frameworks are applicable to the species.

Sustainability and sourcing:
No sustainability or sourcing information is reported.

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No germination or propagation data was added yet.

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No reference genome is available on NCBI yet. We are constantly monitoring for new data.

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