Research notes

What’s been tested on sappan wood, and what was found.

Old practices deserve a sceptic’s eye. Here is every study we cite on sappan wood, the plant in Pinkt. Each card says what sappan material was tested, where it was tested, and what the researchers found. Nothing on this page is a health claim.

Why the water turns pink

Sappan heartwood contains brazilin, which oxidises in air and water into brazilein, the red pigment.

Brazilein, sappan wood’s red pigmentTest tube

What was tested: Brazilein was isolated from sappan wood, dissolved in water at three acidity levels (pH 3, 7 and 9) and then heated.
What it found: It was yellow at pH 3, orange at pH 7 and red at pH 9. The orange and red forms broke down when heated; the yellow form held up better.

Ngamwonglumlert et al., 2020 · Scientific Reports

Sappan wood in water

Pinkt is sappan wood steeped in water, so these are the studies closest to it: water extracts of sappan wood, measured for antioxidant activity in a test tube.

Sappan wood, boiled in waterTest tube

What was tested: Twenty dried Thai medicinal plants, sappan wood among them, were each boiled in water for 10 minutes. The water was then measured for antioxidant activity with a standard test (ABTS).
What it found: Sappan wood had the fifth-highest antioxidant activity of the plants ranked.

Palasuwan et al., 2005 · Asian Pacific Journal of Cancer Prevention

Sappan heartwood, soaked in waterTest tube

What was tested: Dried sappan heartwood powder was soaked in room-temperature water for 24 hours. The water extract was then measured in three standard antioxidant tests (FRAP, ABTS and DPPH).
What it found: The authors describe strong antioxidant and reducing activity. They note that earlier antioxidant results for sappan came from solvent extracts, not water.

Suwan et al., 2018 · Drug Discoveries & Therapeutics

In cells and animals

Concentrated ethanol (alcohol) extracts of sappan wood, tested on cells in a dish and in mice.

Sappan wood, ethanol extractHuman cells in a dish

What was tested: Human cartilage cells and immune cells were made to inflame, then treated with the extract at different strengths.
What it found: The stronger the dose, the lower the inflammatory signals (IL-1β, TNF-α and nitric oxide) the cells produced.

Wu et al., 2011 · Journal of Ethnopharmacology

Sappan wood, ethanol extract, and brazilinMice

What was tested: Mice were given scopolamine, a drug that impairs memory, and then the extract (250 or 500 mg per kg of body weight) or pure brazilin (5 or 10 mg per kg).
What it found: The treated mice did better in a water-maze memory test: they found the hidden platform faster and spent more time in the right part of the pool. Their brains also showed higher levels of memory-related signalling molecules.

Helmi et al., 2021 · Scientia Pharmaceutica

Sappan extract, 91% brazilinMice

What was tested: Mice were given a toxin that damages movement-controlling brain cells, a standard lab model of Parkinson’s disease, and then the brazilin-rich extract.
What it found: Better movement and more protected brain cells, with less inflammation and a change in gut bacteria.

Gao et al., 2025 · ACS Chemical Neuroscience

Safety

Studies in rats and mice, and the review behind the pregnancy caution we carry.

Sappan wood extractRats

What was tested: Rats were given the extract once at 5,000 mg per kg of body weight, or daily for 30 days at 250, 500 or 1,000 mg per kg.
What it found: No toxic signs. Behaviour, deaths, organs, blood tests and tissue examinations matched untreated rats.

Sireeratawong et al., 2010 · Journal of the Medical Association of Thailand

Sappan wood, ethanol extractPregnant rats

What was tested: Twenty pregnant rats per group were given the extract at 100 to 500 mg per kg on days 6 to 15 of pregnancy, and the fetuses were examined at the end.
What it found: Every fetus was alive, with no reabsorptions, no change in fetal weight or length and no malformations. The authors note this differs from the mouse brazilein study below and still advise caution in pregnancy.

Purnama et al., 2023 · HAYATI Journal of Biosciences

Brazilein, sappan wood’s red pigmentMice

What was tested: A general reproductive-toxicity study of brazilein in mice.
What it found: No clear harm to male fertility, but more dead and reabsorbed fetuses and risk to the females. The authors advise caution for pregnant women.

Yuan et al., 2016 · Chinese Journal of Natural Medicines

Sappan wood (Sappan Lignum, “Sumu”)Review

What was tested: A review of the published toxicology, traditional use and pharmacology of sappan wood, which Chinese medicine calls Sumu.
What it found: The toxicology data support the traditional advice to avoid it in pregnancy, and safety depends on the dose and the type of extract.

Chen et al., 2026 · Journal of Ethnopharmacology