Extraction and characterization of Plantago major L. mucilage as a potential natural alternative over synthetic polymers for pharmaceutical formulations

The growing demand for natural cosmetic ingredients with minimal environmental impact has spurred the search for novel alternatives to synthetic materials. In this context, mucilage from Plantago major L., an exotic plant widely spread in Brazil, presents a promising option. This study focused on optimizing mucilage extraction from Plantago major L. seeds, drying the extracted solution, characterizing the dried product, and evaluating its rheological properties for potential cosmetic use. An extraction procedure was developed using a baffled-jacketed stirred vessel with the addition of Teflon® particles to improve seed attrition and enhance seeds' mucilage removal. The mucilage solution was filtered, precipitated by ethanol addition, and then dried on various surfaces, with Teflon® proving the most effective. The product's suitability was evaluated in gel formulations and compared with established commercial polymers. The results showed an optimum extraction yield of 18.4% from the seeds, at the optimum extraction conditions of 140.5 min, solvent-to-seed mass ratio of 0.0284, and a temperature of 80.2 °C. The dried purified mucilage yielded a thermally stable product up to 300 °C, with a structure featuring the fingerprint region between 800 and 1200 cm⁻1, characteristic of carbohydrates. The gel formulation obtained with the product exhibited a non-Newtonian, pseudoplastic rheological profile, resembling the ones prepared with the natural and semi-synthetic polymers such as xanthan gum and hydroxyethyl cellulose, commonly used in cosmetic formulations. This study highlights the potential of mucilage from Plantago major L. seeds for applications in pharmaceutical formulations.