Introduction

Scientists analyzed the potential use of curcumin extracts in colored cotton textiles (CCT) from Paraíba, Brazil (BRS Rubi cultivar) to evaluate curcumin as a potential natural, photoprotective, and antimicrobial dye for everyday clothing. They used an optical microscope to analyze the interwoven structure of cotton with curcumin, revealing a solid textile network.

The key parameter evaluated was the protection provided by colored cotton textiles treated with curcumin when exposed to ultraviolet rays (UPF, ultraviolet protection factor). The colored cotton textiles treated with 10% and 20% curcumin extracts (w/v, indicating the number of grams of curcumin in 100 ml of solution) demonstrated UPF 34 and UPF 36, respectively, falling within the range of average UV protection.

UV Rays: What they Are and What they Cause

What Are UV Rays?

UV rays are ultraviolet radiation (electromagnetic waves) with wavelengths between 100 and 400 nm (nanometers), which are invisible to the human eye. They are responsible for tanning and the production of vitamin D. Most of this radiation comes from the Sun, but it can also come from tanning lamps, mercury vapor lamps, incandescent lights, and some LEDs. Moderate exposure is recommended to avoid potential health risks and to ensure the primary benefit of vitamin D production.

According to the paper, UV rays are essential for many other biological processes, such as photodegradation.

Types of UV Rays

UVA (320-400 nm): About 95% of solar radiation consists of UVA rays, which are emitted year-round. They can easily penetrate the skin (more so than UVB rays). Continuous exposure to these rays causes premature aging of the skin (photoaging) and can also lead to redness, dark spots, wrinkles, and skin cancer.

UVB (280-320 nm): They account for only about 5% of the sun’s rays that reach Earth and are emitted from April through October, which includes the summer months. They cause tanning and are more aggressive than UVA rays, but they can be better blocked by clouds and sunscreen. They can cause sunburn, skin burns, erythema and skin cancer.

UVC (100-280 nm): They are potentially the most dangerous, but fortunately they are filtered out by the ozone layer and therefore do not reach the Earth’s surface.

damage of uv rays

The risk of developing skin cancer depends on a combination of genetic and environmental factors, with prolonged exposure to UV light being the most common cause.
Excessive and prolonged exposure to UV rays leads to changes in the immune system and the accumulation of genetic alterations.

Skin cancer is a global problem, but it is particularly prevalent in Brazil, where skin cancer—whether benign or malignant—is one of the most common type of cancer due to work and sports activities carried out in the sun. Sunscreen, hats, makeup, sunglasses, and protective clothing are essential for protection.

BRS Rubi Cultivar

The naturally colored cotton fabric (CCT) of the BRS Rubi cultivar was chosen as the subject of a study by scientists who found that, by adding curcumin extracts, they were able not only to color the fabric but also to enhance its antimicrobial properties and UV protection.
According to the paper, the acronym “BRS” stands for Brazilian Seeds, and “Rubi” refers to its reddish-brown or earthy color. The BRS Rubi cultivar differs from other brown-fiber cultivars in Brazil in that it has a darker color.

Colored cotton from Paraíba, a state in Brazil located in the northeastern part of the country, is a raw material produced in an ecological and sustainable manner; it is a source of great pride for the country. It is grown without pesticides and has a natural color, eliminating the need for bleaching or chemical dyes. The final product is undoubtedly eco-friendly.

The importance of the study

Curcumin contains bioactive compounds with the following properties: anti-inflammatory, antimutagenic, anticancer, and antibacterial; it also has the ability to absorb UV rays. The simplicity of the method and the easy availability of raw materials demonstrate the benefits of using curcumin extracts to enhance everyday clothing by increasing its UV protection and promoting antimicrobial activity. The colored cotton textiles treated with 10% and 20% curcumin extracts, demonstrated UPF 34 and UPF 36, respectively, falling within the range of average UV protection.

Bibliographic sources:

1. Bento, G.R., Mendes, A.A.P., dos Santos, A.M. et al. Curcuma longa L. as a Natural Photoprotective and Antimicrobial Agent in Colored Cotton Textiles (BRS Rubi) from the State of Paraíba. Fibers Polym, 2026. DOI: https://doi.org/10.1007/s12221-026-01603-5
2. UV Rays: The Differences Between UVA and UVB and Tips for Protection

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