Design,synthesis, and biological activity studies of a new class of sulfonated aurones: First synthesis of acidoaurone isolated from Phyllanthus acidus

A novel series of aurones were designed by introducing sulfonic acid group on ring-A and ring-B of known natural aurones such as hispidol, sulfuretin, maritimetin, and aureusidin. These sulfonated aurones were synthesized by a unique approach. Sulfonation on ring-A or ring-B converts water-insoluble aurones into highly water-soluble aurones. The sulfonated aurones were tested for their antioxidant, antiinflammatory, and AChE inhibition activities along with their natural aurones. Ring-A sulfonated aurones displayed higher antioxidant activity, 5-LOX, and AChE inhibition in comparison with their corresponding natural aurones. Ring-B sulfonated aurones exhibited potent 5-LOX inhibitory activity and significant antioxidant activity. Acidoaurone, a first sulfonated aurone isolated from Phyllanthus acidus was synthesized for the first time and was well characterized using NMR, LC–MS, and further confirmed by HMBC.