Imparting functionality viz color, antioxidant and antibacterial properties to develop multifunctional wool with Tectona grandis leaves extract using reflectance spectroscopy.

In recent years, considerable attention has been given to plant colorants for use in dyeing applications because of their newly discovered properties such as insect repellency, deodorizing, antioxidant, sun protection, and antibacterial activity. In view of their better biocompatibility, biodegradability, less-toxicity, natural colorants are gaining worldwide interest for producing elegant hues and highly functional value-added textiles. In the present work, we investigated the coloring and functional finishing of wool with Tectona grandis L. leaves extract with the emphasis on effect of metallic salt mordants on colorimetric potential, fastness, radical scavenging potential, and antibacterial activity in an attempt to develop bioactive fibres for use in health care applications. The pretreatment of wool with ferrous sulfate, potassium aluminium sulfate and stannous chloride provided a significant enhancement in CIELa*b* parameters and fastness properties. Antioxidant tests showed that the control dyed wool had excellent radical scavenging activity than mordanted samples. In addition, metal mordants particularly ferrous sulfate enhanced the durability of antibacterial efficacy to several laundering cycles. It can be concluded that the extract of Tectona grandis may be developed as multifunctional finishing agent to impart simultaneous color, antioxidant and antibacterial properties to wool based fabrics.

Natural Colorants: Historical, Processing and Sustainable Prospects.

With the public's mature demand in recent times pressurized the textile industry for use of natural colorants, without any harmful effects on environment and aquatic ecosystem, and with more developed functionalities simultaneously. Advanced developments for the natural bio-resources and their sustainable use for multifunctional clothing are gaining pace now. Present review highlights historical overview of natural colorants, classification and predominantly processing of colorants from sources, application on textiles surfaces with the functionalities provided by them. Chemistry of natural colorants on textiles also discussed with relevance to adsorption isotherms and kinetic models for dyeing of textiles.

An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics.

In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R (2) = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R (2) = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL(∗) a (∗) b (∗) and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated.

Phytochemistry, biological activities and potential of annatto in natural colorant production for industrial applications - A review.

Bixa orellana commonly known as annatto is one of the oldest known natural dye yielding plants native to Central and South America. Various parts of annatto have been widely used in the traditional medical system for prevention and treatment of a wide number of health disorders. The plethora of traditional uses has encouraged researchers to identify and isolate phytochemicals from all parts of this plant. Carotenoids, apocarotenoids, terpenes, terpenoids, sterols, and aliphatic compounds are main compounds found in all parts of this plant and are reported to exhibit a wide range of pharmacological activities. In recent years annatto has received tremendous scientific interest mainly due to the isolation of yellow-orange natural dye from its seeds which exhibits high biodegradability, low toxicity, and compatibility with the environment. Considerable research work has already been done and is currently underway for its applications in food, textile, leather, cosmetic, solar cells, and other industries. The present review provides up-to-date systematic and organized information on the traditional usage, phytochemistry and pharmacology of annatto. It also highlights its non-food industrial applications in order to bring more interest on this dye plant, identifies the existing gaps and provides potential for future studies. Studies reported in this review have demonstrated that annatto holds a great potential for being exploited as source of drugs and a potential natural dye. However, further efforts are required to identify extract biomolecules and their action mechanisms in exhibiting certain biological activities in order to understand the full phytochemical profile and the complex pharmacological effects of this plant.