Ecofriendly sonicator dyeing of cotton with Rubia cordifolia Linn. using biomordant Padma S. Vankar a, * , Rakhi Shanker a , Debajit Mahanta b , S.C. Tiwari c a Facility for Ecological and Analytical Testing, Indian Institute of Technology, Kanpur 208 016, India b Arunachal Pradesh State Council for Science and Technology, Vivek-Vihar, Itanagar 791 113, Arunachal Pradesh, India c Department of Forestry, Wildlife and Environmental Sciences, Guru Ghasidas University, Bilaspur 495 009, Chhattisgarh, India Received 28 March 2006; received in revised form 21 June 2006; accepted 16 August 2006 Available online 11 October 2006 Abstract Rubia cordifolia (Tamin, local name) produces anthraquinone reddish orange dyes in roots, stem and leaves, which has been used for dyeing textiles since ancient times. Commercial sonicator dyeing with Rubia showed that pretreatment with biomordant, Eurya acuminata DC var euprista Karth. (Theaceae family) [local name, Nausankhee (Apatani tribe), Turku (Nyishi tribe) in 2%] shows very good fastness properties for dyed cotton using dry powder as 10% of the weight of the fabric is optimum. Use of biomordant replaces metal mordants making natural dyeing ecofriendly. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Rubia cordifolia; Biomordant; Eurya acuminate; Commercial dyeing 1. Introduction A revived interest in the use of natural dyes in textile col- oration has been growing and there is pressing need for the availability of natural dye yielding plants. This is a result of the stringent environmental standards imposed by many coun- tries in a response to the toxic and allergic reactions associated with synthetic dyes. Arunachal Pradesh is recognized as one of the hotspot of biodiversity and the indigenous knowledge sys- tem particularly associated with extraction and processing of natural dyes from plants. From ancient times some tribes of the state were engaged in natural dyeing. The different tribes mainly the Monpas, Apatanis, Nyishis and Adis, respectively, of West Kameng, Tawang, Lower Subansiri and East and West Siang districts of Arunachal Pradesh have been engaged in ex- traction, processing and preparation of dyes using barks, leaves, fruits and roots of the plants from time immemorial. Apatani tribe who have traditionally settled in seven villages in the Ziro valley of Lower Subansiri district of Arunachal Pradesh, use Rubia cordifolia extensively [11]. In this paper we have shown that the natural dye-stuffs of plant origins, grown in Arunachal Pradesh, used as indigenous systems can be developed scientifically and can be substituted for the chemical dyes. These indigenous dyes can be produced in large scale and could be prepared commercially and eco- nomically. The practice of indigenous systems for preparing dye-stuffs and the processes of dyeing has been developed us- ing modern technological methods. These natural dyes derived from the plants of Arunachal Pradesh are found to be of high quality, and thus these plants need to be protected for conservation of biodiversity of the flora of North Eastern region. People can produce these dyes in large scale, commercially, by establishing processing units and can replace the use of chemical dyes which are haz- ardous from the environmental point of view. As Arunachal Pradesh amidst its rich diverse flora harbors many dye yield- ing plant species in abundance, we carried out a study to * Corresponding author. Tel.: þ91 512 2597844; fax: þ91 512 2597436. E-mail address: psv@iitk.ac.in (P.S. Vankar). 0143-7208/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.dyepig.2006.08.023 Dyes and Pigments 76 (2008) 207e212 www.elsevier.com/locate/dyepig