Antidiabetic Potential of Polysaccharides from Indian Tea Cultivars Using in vitro and in vivo Evaluation

Research background. Natural polysaccharides have gained increasing attention because of their potential role in the management of diabetes mellitus. Tea is a widely consumed beverage containing structurally diverse polysaccharides that contribute to its health benefits. However, polysaccharides from Indian tea cultivars remain insufficiently explored, particularly regarding their structural characteristics and antidiabetic potential. Experimental approach. Fresh leaves from six Indian tea cultivars (TV-17, TV-22, Teen Ali, TRF-1, UPASI-9 and UPASI-28) were screened for polysaccharide yield using hot-water extraction followed by ethanol precipitation. Based on their higher polysaccharide content, Teen Ali and UPASI-28 were selected for further structural characterisation by Fourier-transform infrared spectroscopy and scanning electron microscopy. Their antidiabetic potential was evaluated through α-amylase and α-glucosidase inhibition assays and further validated in an alloxan-induced diabetic mouse model. Results and conclusions. The isolated polysaccharides showed characteristic structural features of carbohydrate-rich biomolecules and had distinct morphological properties. Both samples demonstrated significant inhibitory activity against major carbohydrate-hydrolysing enzymes, indicating their potential to regulate glucose metabolism. In vivo studies further confirmed their antidiabetic efficacy through improved glycaemic control, recovery from diabetes-associated body mass loss, and recovery of tissue architecture in treated groups. The observed biological activity may be associated with structural attributes such as hydroxyl groups and uronic acid content, which could enhance interactions with target enzymes. Novelty and scientific contribution. This study provides a comparative investigation of polysaccharides derived from Indian tea cultivars by integrating structural characterisation with both in vitro and in vivo antidiabetic evaluations. The findings contribute to the understanding of tea polysaccharides as potential natural therapeutic agents for diabetes management and highlight the biomedical relevance of underexplored Indian tea varieties.