Valorisation of agricultural waste-derived procyanidin-rich extract from early immature Durio zibethinus L. fruit for sustainable dentin caries management

Early immature Durio zibethinus L. fruit (ED), a valuable feedstock for procyanidin-rich extract (PRE) production, contains substantial concentrations of procyanidin B2 (30.51 mg/g), procyanidin C1 (27.97 mg/g), and epicatechin (18.43 mg/g). This study evaluated the triple anticariogenic potential of ED-derived PRE: (1) antibacterial activity against Streptococcus mutans , (2) dentin matrix stabilisation through endogenous proteolytic enzyme inhibition, and (3) remineralisation of demineralised dentin. Demineralised bovine dentin specimens were treated with 0%, 1%, 3%, or 5% PRE (w/v); next, evaluations were performed by colony-forming unit counts, confocal laser scanning microscopy of S. mutans biofilms, dry mass loss analysis, in situ zymography, Fourier-transform infrared spectroscopy (FTIR), surface nanoindentation, and scanning electron microscopy (SEM) following 21-day storage in simulated saliva. PRE exhibited concentration-dependent antibacterial effects; 5% PRE significantly reduced viable bacterial counts and increased dead bacteria within biofilms ( p < 0.01). All PRE concentrations effectively suppressed proteolytic activity, while 5% PRE achieved the highest phosphate-to-amide ratio ( p < 0.001), comparably dry mass loss, significantly improved nanohardness ( p = 0.02) and elastic modulus ( p = 0.01), and uniform mineral deposition confirmed by SEM. PRE simultaneously targets bacterial colonisation, matrix degradation, and mineral loss; thus, caries management by PRE demonstrates a practical application of circular economy principles aligned with SDG 12 and supports the development of sustainable, cost-effective material production.