Antiviral therapy for chikungunya (CHIKV) and Zika (ZIKV) viruses: Berberine, isolated from berberis, increases spermidine/spermine N1-acetyltransferase (SAT) expression, depletes spermidine and Spermine levels, and restricts Chikungunya and Zika viruses replication via up regulation of its target gene, 10/April/2018, 7.33 pm