ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Plant extracts as environmentally benign corrosion inhibitors in protecting metals from acid media: a review

Vilabeilie Rutsa, Akhiu K. Yimchunger, Therola Sangtam, Vetezo Venuh, Limasenla Longkumer, Liweu Letro, T. Ngipwem Hellen, Azen Aier, and Ambrish Singh

Department of Chemistry, Nagaland University, Zunheboto, India

E-mail: drambrishsingh@gmail.com

Received: 28 October 2025  Accepted: 19 January 2026

Abstract:

The present review article discusses the types of corrosion, their occurrence, and the efficiency of environmentally friendly inhibitors of corrosion on mild steel. Corrosion is a serious challenge in various industries due to its material damage, hazard creation for humans, and high cost. Many phytochemical compounds that are contained in plant extracts take part in the discussion on their efficiency in the corrosion protection activity in acid media. In summary, plant extracts have been used as corrosion inhibitors for a great number of metals and alloys. Scientific progress in green inhibitors is gaining wider interest among people. Inhibitors by chemical origin are applicable under conditions of certain restrictions because of risks involved in them. Natural extracts were employed for retarding corrosion processes because many inhibitors of synthetic origin had adverse impacts. Plant extracts are environmentally friendly and can prevent corrosion in mild steel in acid environments. They substitute hazardous synthetic inhibitors with biodegradable, nontoxic, and inexpensive ones derived from common natural ingredients. These extracts comprise phytochemicals including flavonoids, alkaloids, tannins, and heteroatoms (O, N, S) containing pi-electrons that adsorb through physisorption or chemisorption, resulting in protective coatings that frequently attain inhibitory efficiency surpassing 90%. The manufacturing of these extracts highlights the commitment to environmental stewardship by employing renewable resources, which limit exposure to environmental perils. Plant extracts are multi-functional in action: they act as mixed-type inhibitors, suppressing anodic and cathodic reactions effectively to remain stable for long immersion periods. As more researchers unveil how truly functional natural inhibitors are and how they work, applications are likely to keep growing across more fields and drive new discoveries within green chemistry.

Keywords: Corrosion; Plant-based mitigation; Corrosion inhibitors in HCL and H2SO4

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04684-x

Chemical Papers 80 (5) 4583–4599 (2026)