Hydroxychloroquine is a zinc ionophore that lets zinc into cells. This zinc can block viral replication, which is why researchers are investigating it. But hydroxychloroquine is an available prescription drug in the US because chloroquine had some obnoxious side effect. There is no reason to think that chloroquine and quinine don't act in the same manner. There are also lots of other zinc ionophores that are being investigated. Two of those are quercetin (QCT) and epigallocatechin-gallate.

The interesting thing is that one or both of these are found in green tea and to a lesser extent in black tea, red onions, broccoli, red raspberries, black grapes, and red wine!

Amazon is still taking orders for EGCG green tea extract.