I think there are plants like Cryptoleptis and Sida Acuta that can be used as tonics or to treat Malaria. They are effective against it's lesser known and less virulent cousin Babesia (common in the US via biting insects or blood donations). Test reliability could be improved significantly, including T-cell responses (sound familiar?;-). I think due to the unsustainable cost model of western patented pharmaceuticals and their lack of adaptability and/or side effects, many are also looking into herbal approaches and studies on efficacy & safety.
Sorry, but I don't think this is good advice. Malaria medication does generally work well, I only pointed out that unlike something like Aids and antiretrovirals, it's just not something you can use safely and at scale, for the rest of your life.
If those plants are effective against malaria, it is inevitable that it should be applied in a practical way, which often turns out to be in the form of pills.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956309/