Other natural products U 0800Isolation of the Natural Colorant from the Roots of Arnebia nobilis and Its Use as a New Neutralization Indicator. -Compound (I) is reported to have a much wider pH-range than phenolphthalein or methyl orange, and it is also working in mixtures of strong acid-weak alkali and weak acid-strong alkali, where the two common indicators fail. -(INDRAYAN*, A. K.; YADAV, V.; KUMAR, R.; TYAGI, P. K.; J. Indian Chem.