Screening and implementation of Bougainvillea spectabilis Willd (Rosea, Alba and Flava) bract extracts as an indicator in acid–base titrations

Abstract

Background: Natural pigments present in different plants are highly colored substances and contributes to color changes with variation of pH. Aims: This study was deliberated to evaluate the flower pigment extracts obtained from Bougainvillea spectabilis bracts (Nyctaginaceae) as a titration indicator. Settings and Design: Three different varieties (Rosea, Alba, and Flava) of B. spectabilis were used for the isolation of extract. Acidified methanolic extracts were used as an indicator in different strong acid-strong base (HCl and NaOH), strong acid-weak base (HCl and NH3), weak acid-strong base (CH3COOH and NaOH), and weak acid-weak base (CH3COOH and NH3) titrations. A comparative study of B. spectabilis extract a natural indicator, with synthetic indicator phenolphthalein, methyl red, and phenol red was conducted to evaluate its accuracy as an acid-base indicator. Statistical Analysis Used: Further, the data were subjected to one-way analysis of variance analysis for analyzing the statistical difference. Results and Conclusions: Result showed that in all these titrations the Bougainvillea bract extracts were found to be accurate, useful and for indicating the end point (neutralization point). It gives sharp and intense color change, and results were found to be statistically significant (P < 0.05) as compared to phenolphthalein, methyl red, and phenol red. The presence of betalains in B. spectabilis bracts mainly contributes to the color change at different pH. From this, it can be concluded that B. spectabilis bract extracts of different varieties are emerging as a novel, very useful, economical, simple, accurate, environmentally and user-friendly indicator. This discovery can be a value addition to the plethora of numerous indicators available. From these investigations, new theories of indicators could be established.