What exactly is Sappanwood?

Sappanwood, scientifically known as Caesalpinia sappan L., is a tropical plant also called “kayu secang” in Indonesia. It's heartwood contains brazilin, which oxidizes into brazilein, the compound responsible for the vibrant colors. Sappanwood has been used traditionally in medicine and as a natural dye. It's valued for its pharmacological effects, including anti-inflammatory properties and potential cancer cell inhibition.

What is brazilein and why is it important in sappanwood dye?

Brazilein is the active compound derived from sappanwood that gives the natural dye its color. It is created when brazilin oxidizes. It's important because it's water-soluble, historically used in dyeing ancient fabrics, and increasingly used as a food colorant, pH indicator and in dye-sensitized solar cells. The color spectrum of brazilein can be manipulated from yellow to red based on pH levels and mordants used during the dyeing process.

What are mordants and what role do they play in modifying Sappanwood dye?

Mordants are metal salts that are used in the dyeing process. They serve two primary purposes: fixing the dye (like brazilein) to textile fibers and modifying the color's depth. They can create a range of diverse shades from the same dye origin (Sappanwood).

What are acid-base treatments and cation additions and how do they modify the colors in Sappanwood dye?

Acid-base treatments involve adding acids or bases to sappanwood extracts to modify the color characteristics. For example, citric acid or acetic acid can create acidic conditions, while sodium hydroxide or calcium hydroxide can create basic conditions. These treatments alter the pH of the solution, which in turn affects the color spectrum of brazilein. Cation additions work similarly using solutions like Cu-Acetate, MgSO4, FeSO4, and Al2(SO4)3 to observe changes in color spectra.

What is a UV-Vis spectrophotometer and how is it used when working with Sappanwood dye?

A UV-Vis spectrophotometer is a device used to quantitatively measure the absorbance of light by a substance, like sappanwood extract. In the context of dyeing, it's used to record data at optimum wavelengths for each color spectrum after the sappanwood extract has been modified using acid-base treatments or mordants. This allows researchers and users to understand and control the resulting color changes.

Vibrant colors swirling out of sappanwood heartwood log.

Unlock Vibrant Colors: How to Naturally Modify Sappanwood Dye for Stunning Results

Lena Kashyap in Tech & Innovation December 2025 • 4 min read.

"Explore the secrets of enhancing natural dyes with simple chemical modifications to intensify color and expand the spectrum of brazilein extract from Sappanwood."

Sappanwood (Caesalpinia sappan L.), known as “kayu secang” in Indonesia, has a long history of use in traditional medicine and as a natural dye. This tropical plant is valued for its pharmacological effects, ranging from anti-inflammatory properties to potential cancer cell inhibition. The heartwood is a source of brazilin and brazilein, the active compounds responsible for its vibrant colors.

Brazilin itself is colorless, but its oxidized form, brazilein, yields a natural color widely used in textile dyeing. Its appeal stems from its water solubility and the historical evidence of its use in ancient fabrics. Beyond textiles, brazilein is gaining traction as a food colorant, pH indicator, and even in dye-sensitized solar cells, highlighting its versatility.

The color spectrum of brazilein varies from yellow to red, influenced by the pH of the solution and the mordants used in the dyeing process. Mordants, typically metal salts, not only fix the dye to the textile fibers but also modify the color’s depth and create diverse shades from the same origin. This article explores how simple chemical modifications can dramatically alter the color intensity and spectrum of sappanwood extract, offering a practical guide to optimizing its use.

Mastering Color Modification: How to Alter Sappanwood Dye with Simple Chemistry

Vibrant colors swirling out of sappanwood heartwood log.

Researchers explored how acid-base treatments and mordant additions affect the color characteristics of sappanwood extract. The goal was to systematically understand how these modifications can expand the intensity and spectra of the colors, making it easier for users to achieve specific results.

The study involved treating aqueous extracts of sappanwood with different chemical additives and then meticulously measuring the resulting color changes using a UV-Vis spectrophotometer. Here’s a look at the methods used:

Extraction: Brazilein was extracted from shaved sappanwood using a high-speed liquid blender with aquadest as a solvent, maintaining a concentration of 0.002 g/L, mixing speed of 300 rpm, and a temperature of 100°C for 70 minutes.
Acid-Base Modification: Citric acid or acetic acid (0.1 M) was added to the extract to create acidic conditions, while sodium hydroxide or calcium hydroxide (0.1 M) was used for basic conditions.
Cation Addition: Solutions of Cu-Acetate, MgSO4, FeSO4, and Al2(SO4)3 were tested as cation providers to observe changes in color spectra.
Measurement: A UV-Vis spectrophotometer was used to quantitatively measure the absorbance of the modified extracts, recording data at optimum wavelengths for each color spectrum.

The data collected offers valuable insights into the fundamental mechanisms that govern the color changes in sappanwood extract under different chemical conditions.

Key Takeaways: Simple Chemistry, Stunning Colors

By understanding the effects of acid-base treatments and mordant additions, users can systematically optimize the application of natural dyes like sappanwood. Whether you're aiming for subtle shifts or dramatic transformations, these techniques provide a foundation for achieving your desired color outcomes.