Tailored Momordica charantia Fruit Biomass Nanocellulose Surfaces via Acid Hydrolysis and Catalytic Oxidation for In-vitro Antioxidant, Anti-inflammatory and Anti-diabetic Activities

This study reports the synthesis of sulfated cellulose nanocrystals (S-CNC; 23% yield) and carboxymethyl cellulose nanocrystals (CM-CNC; 17% yield) from Momordica charantia fruit biomass via sulfuric acid hydrolysis and TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl)-mediated oxidation, respectively. Comprehensive characterization confirmed sulfate (S=O at 1220–1260 cm⁻¹; 0.95 wt% S by EDS) and carboxylate (C=O at 1600–1740 cm⁻¹; C/O 45.62/54.38 wt%) functionalization, alongside preserved cellulose Iβ crystallinity (S-CNC: 92.78%, 6.29 nm crystallites; CM-CNC: 90.37%, 10.65 nm). Both materials exhibited potent antioxidant activity- 2,2-diphenyl-1-picrylhydrazyl (DPPH)/(ABTS) (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)/superoxide scavenging: 67–79% at 1000 µg/mL vs. 96–97% ascorbic acid, and anti-inflammatory effects (egg albumin/Bovine Serum Albumin denaturation/Human RBC cells stabilization: 65–78% at 1000 µg/mL vs. 87–90% diclofenac), with S-CNC outperforming CM-CNC. Antidiabetic potential was evident in α-amylase/α-glucosidase inhibition (41–62% at 1000 µg/mL vs. 76–77% acarbose) and enhanced insulin secretion from RIN-5F β-cells (S-CNC: 9.3-fold at 250 µg/mL; CM-CNC: 7.8-fold vs. 11.9-fold glucose control; p < 0.001). Minimal cytotoxicity (>68% viability at 500 µg/mL in RIN-5F cells vs. Streptozotocin control) underscores biocompatibility. These M. charantia -derived nanocelluloses offer promising scaffolds for diabetes management.