Cholinesterase Inhibitory Activities of Halenaquinolsulfate from the Sponge Petrosia nigricans

The high incidence of Alzheimer’s disease (AD) required a continued exploration of promising molecules that demonstrated good affinities with the pharmacological targets of AD. This study presented cholinesterase (ChE) inhibitor screening of sponge extracts from under-explored waters, in Bali, Indonesia. The study identified ten sponges whose extracts exhibited low to high AChE inhibition percentages. One of the sponge extracts, Petrosia nigricans, displayed the highest inhibition 95.17%. Subsequent chromatographic purification of the extract returned a known pentacyclic hydroquinone, halenaquinolsulfate (HQS). This report was the first study on identifying HQS from the sponge of the genus Petrosia. Next, the compound displayed moderate acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitions with IC₅₀values of 40.73±0.19 µg/mL and 53.12±0.32µg/mL respectively. This study expands the cholinesterase activities of the pentacyclic hydroquinone class of compounds isolated from marine sponges.