This study demonstrates that SQDG isolated from the leaves of Azadirachtaindica exerts selective and potent anti-ALL effects by inhibiting DNArelaxation activity of topo I. Silencing of TOP1 gene in MOLT-4 and Reh celllines increased resistance of these cell lines for SQDG treatment, suggesting thatSQDG mediated MOLT-4 and Reh cell killing is mediated by topo I inhibition. Here, TOP1 is linked to acute lymphoblastic leukemia.