Indigo Carmine: Between Necessity and Concern

Abstract

Dyes, such as indigo carmine, have become indispensable to modern life, being widely used in the food, textile, pharmaceutical, medicine, and cosmetic industry. Although indigo carmine is considered toxic and has many adverse effects, it is found in many foods, and the maximum permitted level is 500 mg/kg. Indigo carmine is one of the most used dyes in the textile industry, especially for dyeing denim, and it is also used in medicine due to its impressive applicability in diagnostic methods and surgical procedures, such as in gynecological and urological surgeries and microsurgery. It is reported that indigo carmine is toxic for humans and can cause various pathologies, such as hypertension, hypotension, skin irritations, or gastrointestinal disorders. In this review, we discuss the structure and properties of indigo carmine; its use in various industries and medicine; the adverse effects of its ingestion, injection, or skin contact; the effects on environmental pollution; and its toxicity testing. For this review, 147 studies were considered relevant. Most of the cited articles were those about environmental pollution with indigo carmine (51), uses of indigo carmine in medicine (45), and indigo carmine as a food additive (17).

Effects of Indigo Carmine on Growth, Cell Division, and Morphology of Allium cepa L. Root Tip

“…For instance, the concentration of 0.2 mg/mL is equivalent to the concentration of indigo carmine in candied fruit, candies, nougats, fine bakery wares, aromatized alcoholic beverages, etc. [ 1 ]. However, in our study, we also considered lower concentrations of indigo carmine because the toxic effect of a substance also depends on the exposure time, and our experiment lasted only 5 days.…”

“…Indigo carmine is an intensively used dye, but at the same time can be a threat to the environment and human health [ 1 ]. Indigo carmine is a dark blue and water-soluble powder known as indigotine, E132, 5,5′-indigodisulfonic acid sodium salt, etc.…”

“…[ 7 , 15 ]. The European Food Safety Authority allows the use of indigo carmine in food and beverages with maximum permitted levels between 50 and 500 mg/kg [ 1 , 16 ], while the Codex Alimentarius Commission has approved maximum levels ranging from 50 to 450 mg/kg [ 1 , 17 ]. The U.S. Food and Drug Administration (USFDA) has not established maximum levels for this food additive but allows its use under good manufacturing practices in a number of foods as listed in the Code of Federal Regulations [ 1 , 18 ].…”

“…It can increase water turbidity, affect plant photosynthesis, and accumulate in aquatic organisms [ 36 ]. In addition, water contaminated with indigo carmine changes color and odor and becomes non-potable even at very low concentrations [ 1 ].…”

Study of PEG-b-PLA/Eudragit S100 Blends on the Nanoencapsulation of Indigo Carmine Dye and Application in Controlled Release

“…This process was obtained by taking an encapsulation approach to entrap water-soluble substances within the aqueous core of hydrophobic nanocapsules, namely, the water-in-oil-in-water (W 1 /O/W 2 ) double emulsion method . The model dye IC has already been established as a suitable agent in a wide variety of applications including as a diagnostic tool in clinical medicine. − The encapsulating material was based on a solution blend of two biocompatible polymers that could form a negatively charged interior wall. Specifically, the binary blend was composed of poly­(ethylene glycol)- block -poly­( d , l -lactic acid) (PEG- b -PLA with PEG and PDLLA molecular weights of 5 and 100 kDa, respectively) with 10% w/w Eudragit S100 (1:2 copolymer of methacrylic acid and methyl methacrylate).…”