Azo dyes have been extensively utilized in various industries, establishing themselves as the predominant organic dyes in global markets owing to their diverse color range, high tinctorial strength, and excellent color fastness. However, it is imperative to acknowledge the associated health risks, including allergies, cancers and mutations, attributed to azo dyes. In contrast, natural dyes possess low sensitization, biodegradability, and environmental friendliness, thereby exhibiting significant potential for replacing high-risk azo dyes. Flavonoids, natural compounds derived from plants, have been utilized in dyes, pigments, cosmetic products, and even foods. The extract from heartwood has rich flavonoids, endowing good photostabilities to prevent wood from UV-induced degradation. However, the wood protection ability of these flavonoids would be shaded when exposed to UV light with heat and water, owing to their photo-chemical characteristics. These problems need to be solved if the flavonoids are applyed as wood photostabilzers. Hence, this study is to explore the feasibility of extracts from as natural dyes with wood photostability through mordant-dyeing process. The findings reveal that the heartwood extract and its ethyl acetate fractions, abundant in flavonoids and condensed tannins, can form chelated structures, exhibiting distinct colors when combined with CuCl and FeCl. This results in the red-brown and dark brown appearance of wood, respectively. Significantly, the specimens treated with CuCl- and FeCl-mordanted heartwood extract demonstrate excellent color fastness against heat and water. Moreover, these extracts exhibit the ability to absorb UV light and neutralize free radicals, enhancing the UV light resistance of color fastness. As a result, the mordant-dyed extract not only contribute various colors to wood but also enhance their photo resistance by excellent photostability. These outcomes also pave the way for expanding the applications of extracts and establish systematic methodologies for natural dyes applied on wood products.

中文翻译：

---

相思心材提取物环保型木材着色剂的开发


偶氮染料已广泛应用于各个行业，凭借其多样化的颜色范围、高着色强度和优异的色牢度而成为全球市场上占主导地位的有机染料。然而，必须承认偶氮染料带来的相关健康风险，包括过敏、癌症和突变。相比之下，天然染料具有低致敏性、可生物降解性和环境友好性，因此表现出替代高风险偶氮染料的巨大潜力。类黄酮是从植物中提取的天然化合物，已被用于染料、颜料、化妆品甚至食品中。心材提取物含有丰富的黄酮类化合物，具有良好的光稳定性，可防止木材因紫外线引起的降解。然而，由于它们的光化学特性，这些类黄酮的木材保护能力在暴露于紫外线、热和水时会减弱。将黄酮类化合物用作木材光稳定剂需要解决这些问题。因此，本研究旨在探索通过媒染工艺将木材提取物作为具有木材光稳定性的天然染料的可行性。研究结果表明，心材提取物及其乙酸乙酯部分富含类黄酮和缩合单宁，可以形成螯合结构，与 CuCl 和 FeCl 结合时呈现出独特的颜色。这分别导致木材的红棕色和深棕色外观。值得注意的是，用 CuCl- 和 FeCl- 媒染的心材提取物处理的样品表现出优异的耐热和水色牢度。此外，这些提取物表现出吸收紫外线和中和自由基的能力，增强了色牢度的耐紫外线能力。 因此，媒染提取物不仅为木材提供了多种颜色，而且通过优异的光稳定性增强了其耐光性。这些成果也为扩大提取物的应用和建立用于木制品的天然染料的系统方法铺平了道路。