High performance thin-layer chromatographic (HPTLC) profiling and bioactivity assessment of aroma-enhanced Indian tea blends: In vitro and in silico insights

The rising prevalence of oxidative stress-associated metabolic disorders, particularly diabetes, underscores the urgent need for culturally relevant, plant-based therapeutic interventions. This study investigates the antioxidant, antidiabetic, and anti-inflammatory potential of Indian black teas-Darjeeling and Ooty in both traditional (non-aromatic) and aromatic (spice-enriched) formulations. High-performance thin-layer chromatography (HPTLC) revealed key bioactives including rutin, gallic acid, catechin, quercetin, and ferulic acid, with catechin predominating in Ooty tea and quercetin and ferulic acid enriched in aromatic variants. Aromatic Ooty tea exhibited the highest flavonoid content (42.9 ± 0.9 mg rutin/g), while its non-aromatic counterpart showed superior total phenolic content (2835.1 ± 39.5 mg GAE/100 g). Antioxidant activity, measured via DPPH and FRAP assays, was notably high in aromatic teas, especially in Darjeeling masala tea (DMT), which exhibited the highest FRAP value. Antidiabetic potential, assessed through α-amylase and α-glucosidase inhibition, was the strongest in aromatic Ooty tea (OMT) and non-aromatic Darjeeling tea (DT), respectively. In vitro safety and anti-inflammatory effects were confirmed using Caco-2 and RAW 264.7 cell lines, with significant nitric oxide reduction in LPS-stimulated macrophages. In silico molecular docking and MM-GBSA binding energy calculations validated the strong interactions of rutin and quercetin with key metabolic enzymes, supporting the in vitro results. These findings highlight aromatic Indian teas, particularly spice-enriched Ooty and Darjeeling variants, as potent and accessible future functional beverages in combating oxidative stress and diabetes.