Stress-Induced Phytochemical Enhancement and in vitro Antidiabetic and Anti-Inflammatory Activities of Soil-Grown Urad Microgreens: A Comparative Study

Objectives

Microgreens are tender edible seedlings harvested 7-21 days after germination at a height of 2.5-7.5 cm. They are rich in bioactive compounds and possess potential health benefits. The present study aimed to quantify major phytochemicals, including phenolics and flavonoids, in urad (Vigna mungo) microgreens grown under different stress conditions and to evaluate their in vitro antidiabetic and anti-inflammatory activities.

Materials and Methods

Urad microgreens were cultivated under normal conditions, 25%, 50%, and 100% salinity stress, and 24-hr dark stress. Ethanolic extracts (70-80%) were prepared for phytochemical analysis. Total Phenolic Content (TPC), Total Flavonoid Content (TFC), anthocyanin, chlorophyll, and carotenoid levels were estimated. Antidiabetic activity was assessed using the α-amylase inhibition assay, while anti-inflammatory activity was evaluated through the egg albumin denaturation assay.

Results

Phytochemical screening confirmed the presence of alkaloids, carbohydrates, phenolics, flavonoids, and steroids. TPC was highest at 100% salinity (0.1422±0.0012 mg GAE/g), whereas TFC and anthocyanin peaked at 50% salinity (0.5969±0.2238 mg QE/g and 0.3197±0.0011 µg/g FW, respectively). Pigment content was maximum under normal conditions. Dark-grown microgreens showed elevated flavonoids but reduced phenolics, anthocyanins, and bioactivity. Microgreens grown under normal photoperiod exhibited the strongest α-amylase inhibition (IC₅₀ 55.98 µg/mL) and anti-inflammatory activity (IC₅₀ 9.24 µg/mL).

Conclusion

Moderate salinity (50%) enhanced flavonoid accumulation, while normal conditions produced superior bioactivity, highlighting stress-induced urad microgreens as promising functional foods.