Disclosed are compounds represented by general formula (I), wherein X is O, S or NR, and R25 and R26 together form a heterocyclyl or heteroaryl ring. Also disclosed is the use of the compounds of formula (I) for inhibiting or preventing alpha-synuclein toxicity and/or fibril formation, inhibiting or preventing alpha-synuclein fibril growth, and/or causing disassembly, disruption, and/or disaggregation of alpha-synuclein fibrils and alpha-synuclein-associated protein deposits.