Phytochemical screening and pH-responsive indicator potential of Curcuma aromatica rhizome extracts for green analytical applications

Curcuma aromatica Salisb., commonly known as Wild Turmeric or Jungli Haldi, is a medicinally important plant widely recognized for its rich phytochemical composition and traditional therapeutic applications. The present study was undertaken to investigate the phytochemical constituents and natural pH-responsive indicator potential of Curcuma aromatica rhizome extracts prepared using solvents of varying polarity, including methyl acetate, ethyl acetate, dichloromethane, carbon tetrachloride, and hot water. Qualitative phytochemical screening revealed the presence of several bioactive secondary metabolites such as alkaloids, flavonoids, terpenoids, tannins, phenolic compounds, saponins, carbohydrates in different solvent extracts, whereas glycosides, proteins, and amino acids were absent under the present experimental conditions. The distribution of phytochemicals was found to vary depending on the polarity of the extraction solvent.
The ethanolic rhizome extract was further evaluated for its application as a natural acid–base indicator and herbal pH-sensitive paper. The extract exhibited a distinct colour transition from yellow in acidic medium to reddish-brown in alkaline medium, indicating significant pH-responsive behaviour. Comparative titration studies performed using standard synthetic indicators demonstrated that the endpoint observations and titre values obtained with Curcuma aromatica extract were closely comparable to conventional indicators. In addition, the prepared herbal pH strips showed rapid, clear, and reproducible colour responses in acidic, neutral, and basic solutions.
The findings of the present investigation highlight the dual significance of Curcuma aromatica as both a phytochemically valuable medicinal plant and an eco-friendly analytical material. Its biodegradable, economical, and non-toxic nature suggests considerable potential for application in green chemistry, sustainable laboratory practices, and educational analytical experiments as a natural alternative to synthetic pH indicators.