Rare Plant-Derived Polysaccharides as Next-Generation Drug Delivery Carriers: Opportunities, Challenges, and Future Perspectives

Rare plant-derived polysaccharides have emerged as promising biomaterials for advanced drug delivery due to their structural adaptability and functional performance. This review critically evaluates polysaccharides from underutilized sources such as tamarind seed, fenugreek, bael fruit, jackfruit, okra, aloe, and Plantago ovata. Tamarind polysaccharide-based systems demonstrate high encapsulation efficiency (>70%) and sustained drug release beyond 8–12 h with enhanced mucoadhesion and prolonged residence time. Thiolated fenugreek mucilage exhibits improved swelling and controlled release in gastroretentive formulations. Bael and jackfruit polysaccharides provide good mechanical strength and stability in matrix and nanocarrier systems. Okra-based formulations show high drug entrapment (>75%) and extended release, supporting colon-targeted delivery. Aloe polysaccharide hydrogels enable sustained release and improved tissue regeneration, while Plantago ovata allows enzyme-triggered site-specific drug release. Despite these advantages, variability, limited toxicity data, and scale-up challenges hinder clinical translation. Overall, these polysaccharides offer improved functional performance over conventional polymers and require further standardization for pharmaceutical applications.