No, MXC is not using hydroxychloroquine (synthetic). They are using Artemisinin (botanical) - based on below, it is believed to have more potent binding to particular hot spots on the COVID-19 spike proteins.
"In-silico Studies of Antimalarial-agent Artemisinin and Derivatives Portray More Potent Binding to Lys353 and Lys31-Binding Hotspots of SARS-CoV-2 Spike Protein than Hydroxychloroquine: Potential Repurposing of Artenimol for COVID-19."
Unlike with Hydroxychloroquine, Artemisinin has good safety and toxicity profiles based on it's history in treating drug resistant malaria.
"Safety was assessed by analysing adverse events, as well as clinical laboratory (haematology assessed in 4,062, blood chemistry in 3,893 patients), electrocardiographic (2638 patients) and neurological assessments as reported in the papers. No serious adverse event or severe significant toxicity was reported. Overall, the most commonly reported adverse experiences were gastro-intestinal. Occasional neutropenia (1.3%), reticulocytopenia (0.6%), elevated liver enzymes (0.9%) were reported."
