Natural Plant Extracts as Acid-Base Indicator

Natural Plant Extracts as Acid-Base Indicator

Author Name : Dr. Sundhararajan R, Mrs. R. Jothilakshmi, S. Vishva Balan, C. Yuvanraj, S. Yokesh, G. Pavin Kumar, M. Mohamed Nazeem

DOI: https://doi.org/10.56025/IJARESM.2025.1302251059

ABSTRACT Herbal indicators are plant-derived natural pH indicators that exhibit distinct color changes in response to acidic or basic environments. These eco-friendly alternatives to synthetic indicators are gaining significant attention due to their non-toxic, biodegradable, and cost-effective nature. Various plant extracts, such as those from hibiscus, red cabbage, turmeric, beetroot, and butterfly pea flowers, contain bioactive compounds like anthocyanins, flavonoids, and curcumin, which undergo structural transformations at different pH levels, leading to visible color variations. The increasing demand for sustainable and green chemistry solutions has driven research into the effectiveness of herbal indicators in titrations, pharmaceutical testing, and environmental monitoring. Unlike synthetic indicators such as phenolphthalein and methyl orange, which may pose health and environmental risks, herbal indicators provide a safer alternative for laboratory and educational applications. Extraction methods, including maceration, infusion, and solvent extraction, are commonly used to obtain these plant-based indicators. Their stability and accuracy can be enhanced through formulation techniques such as microencapsulation and the addition of stabilizing agents. Studies have shown that herbal indicators offer comparable accuracy to conventional chemical indicators while reducing chemical waste and pollution. However, further research is needed to optimize their stability, expand their pH sensitivity range, and explore their applications in diverse fields such as food safety, cosmetics, and pharmaceuticals. The development of standardized herbal indicator formulations could pave the way for their commercial adoption in analytical and industrial processes.