The scientific findings presented here are derived from a series of studies conducted by Shikoku University (Tokushima, Japan).

These studies examined the functional components of Persicaria tinctoria (Japanese indigo), including trypanthrin, indirubin, and kaempferol, and evaluated their effects on inflammation, metabolism, lipid regulation, and blood glucose control.

Additional long-term safety evaluations, including chronic toxicity testing and Ames mutagenicity testing, were also carried out, confirming the safety of indigo leaf powder as a dietary ingredient.

🌿 Active Compounds in Japanese Indigo Leaves: Scientific Summary

1. Which Indigo Compounds Drive the Health Benefits?

Researchers examined which polyphenols in Persicaria tinctoria (Japanese indigo) are responsible for its biological effects.
Although tannic acid accounts for the majority of indigo-leaf polyphenols, experiments showed that tannic acid alone did not produce the same effects, meaning the benefits are not due to tannins.

Instead, three key polyphenols were identified:

• Tryptanthrin – antimicrobial, anti-inflammatory, cancer fighting active compound

• Indirubin – anti-inflammatory, cell-regulating

• Kaempferol – antioxidant, metabolic support

2. Study Design (Simplified Overview)

To determine the effect of each compound, researchers fed male rats a high-fat diet and supplemented it with specific indigo polyphenols.

Six groups were tested:

1. High-fat diet only (HF)

2. HF + Tryptanthrin (HF-T)

3. HF + Kaempferol (HF-K)

4. HF + Indirubin (HF-I)

5. HF + Tryptanthrin + Indirubin (HF-TI)

6. HF + Tryptanthrin + Kaempferol + Indirubin (HF-TKI)
   (The added amounts matched the levels found in a diet containing 1% indigo leaf powder)

Food intake was similar across groups, meaning differences were due to indigo compounds

rather than calorie reduction.

4. Safety Evaluation of Indigo Leaves

(1) Chronic Toxicity Study (26 Weeks)

A long-term safety test was performed using male and female Wistar rats.

Groups:

• Control (AIN-93G bass diet only)

• Low-dose (AIN-93G + 1% indigo leaf powder)

• High-dose (AIN-93G + 5% indigo leaf powder)

Results (Males & Females):

• No deaths in any group over 26 weeks

• No organ enlargement or atrophy

• Body weight curves similar across groups

• Female rats showed a mild suppression of weight gain, consistent with earlier findings and not a sign of toxicity

📌 Conclusion:
Even at high doses for 6 months, indigo leaf powder showed no toxic effects.

(2) Ames Test (Mutagenicity Test)

A standard mutation test was conducted by the Japan Food Research Laboratories.

Result:

• Negative (no mutagenicity, no carcinogenic risk)

📌 Conclusion:
Indigo leaf powder shows no genotoxicity and is considered safe as a functional food.

3. Key Findings

(1) Body Weight Suppression

• Tryptanthrin and

• Indirubin
  → Both significantly suppressed weight gain (similar to whole indigo-leaf powder).

(2) Reduction of Visceral Fat

• Tryptanthrin
  → Showed the strongest reduction in abdominal fat.

(3) Lowering of Serum Triglycerides

• Tryptanthrin

(4) Lowering of Blood Glucose

• Tryptanthrin and

• Kaempferol

Overall Summary

Indigo leaves contain a unique combination of tryptanthrin, indirubin, and kaempferol, which together:

• Support healthy weight management

• Reduce visceral fat

• Improve blood lipids

• Improve blood glucose

• Provide antimicrobial and anti-inflammatory benefits

• Offer strong antioxidant protection

Safety evaluations confirm that indigo leaf powder is non-toxic, non-carcinogenic, and suitable as a long-term functional food.

🥰✨Free gift for you to downloard beautiful 2 page printable💖🙏

FAQ

Q. Is IROHA Indigo Powder safe?

Yes. IROHA Indigo (Persicaria tinctoria) is organically grown in the mountains of Japan and inspected for pesticide residues, heavy metals, and microbial safety.
Studies conducted at Shikoku University (chronic toxicity tests + Ames test) confirmed:
• No toxicity
• No carcinogenicity
• Safe for long-term consumption

Q. Is it safe during pregnancy or breastfeeding?

Although natural, we recommend consulting a doctor or midwife.
If used, start with a very small amount such as a weak tea.

Q. How much should I take per day?

For general wellness, the recommended amount is 1–2 grams per day(about ¼–½ teaspoon).
If using capsules, 1–2 capsules per day is typical.

Q. Is edible indigo the same as indigo dye?

They come from the same plant, but:

• Edible indigo → dried leaf powder

• Dye indigo → fermented leaf paste (“sukumo”) used in textile dyeing

Eating the powder does not dye your mouth or clothing.

Q. What does indigo powder taste like?

It has a mild, herbal flavor—somewhere between green tea and a light Japanese herbal infusion. It is far less grassy than typical green superfood powders.

Q. Is the quality reliable even though it’s imported?

Yes.
IROHA Indigo is grown, harvested, and processed entirely in Japan under strict hygiene standards, then exported to Australia as a food product compliant with FSANZ.
It meets Australian import requirements for herbal food items.

Q. What are the recommended ways to take it?

You can enjoy Indigo Powder in many ways:

• Dissolve in warm water as a herbal tea

• Mix into smoothies, protein shakes, or yogurt

• Add to curries, soups, or broths

• Place into capsules and swallow

Indigo’s beneficial compounds are heat-stable, so it can be used in cooking.

Q. What benefits can I expect?

Based on traditional use and modern research, indigo may support:

• Anti-inflammatory action (tryptanthrin, quercetin)

• Strong antioxidant effects (4× more polyphenols than blueberries)

• Healthy blood sugar balance

• Reduced triglycerides

• Improved metabolic response

• Skin-calming properties (traditional use: rash, irritation)

These are health-supportive benefits—not medical treatment claims..

Q. How far back does indigo’s history go?

Indigo’s origin reaches back to 3000 BCE (Indus Valley Civilization).
In Japan, indigo spread during the Nara period and became essential for dyeing, medicine, and daily life.
People used to say:
“Indigo merchants never get sick.”
It was carried as a travel remedy and used for fever, detox, and wound care.

Q. How is indigo different from other blue superfoods like spirulina?

Q. How should I store it?

Yes, but begin with a very small amount (just a tiny pinch) and observe their response.

Q. Can children take it?

Keep in a cool, dry, dark place.
After opening, store in an airtight container and consume as soon as possible.

✨Please contact us if you have any questions🥰🙏

Projects

Exploring indigo and other Japanese herbs’ healing potential through research

Herbal Study

Analyzing tade-ai’s antioxidant properties

Wellness Trials

Testing natural remedies for skin and gut health and anti-aging detox