Scirpusin B isolated from Passiflora edulis Var. flavicarpa attenuates carbohydrate digestive enzymes, pathogenic bacteria and oral squamous cell carcinoma

Passiflora edulis Var. flavicarpa (passion fruit) generates vast waste (60–70%) in the form of peel and seed after the juice extraction. The study aimed to isolate Scirpusin B (SB) from passion fruit (PF) seed waste collected from Northeast India and to analyse its anti-radical, antibacterial, anti-diabetic, and anti-oral cancer activities. Scirpusin B was isolated following hydro-alcoholic extraction, fractionation, and column chromatography. The isolated fraction was further identified through NMR and mass spectroscopy. SB exhibited significant antiradical activity against six standard antioxidant compounds, indicating its commercial application. SB inhibited α-amylase (IC₅₀ Value: 76.38 ± 0.25 µg/mL) and α-glucosidase digestive enzymes (IC₅₀ Value: 2.32 ± 0.04 µg/mL), signifying its antidiabetic properties. In addition, SB showed profound antibacterial activity against eight gram-positive and gram-negative bacteria reported for the first time. Furthermore, SB inhibited SAS and TTN oral cancer cell proliferation up to 95% and 83%, respectively. SB significantly inhibited colonies of SAS and TTn cells in the clonogenic assay, attributing to its anticancer properties. The PI-FACS assay confirmed the ability of SB (75 µM) to kill SAS and TTn cells by 40.26 and 44.3% in 72 h. The mechanism of SB inhibiting oral cancer cell proliferation was understood through western blot analysis, where SB significantly suppressed different cancer hallmark proteins, such as TNF-α, survivin, COX-2, cyclin D1, and VEGF-A. The present study suggests that SB isolated from PF seed can add noteworthy value to the waste biomass for various industrial and medical applications.