3,3'4-trimethoxy-4'-rutinosylellagic acid and its acetylated derivative: Antioxidant activity and antiproliferative effects on breast cancer cells and molecular docking study.

Cancers account for many deaths worldwide and natural compounds and their derivatives are interesting chemotherapeutic agents for cancer drug development. In this study, a natural compound 3,3'4-trimethoxy-4'-rutinosylellagic acid (TR2) and its acetylated derivative 3,3'4-trimethoxy-4'-hexaacetylrutinosylellagic acid (TR22) were evaluated for their antioxidant and anticancer effects against estrogen sensitive (MCF-7) and estrogen non-sensitive (MDA-MB 231) breast adenocarcinoma. In the ß-Carotene-linoleic acid assay, DPPH• radical scavenging and CUPRAC assay, the compound TR2 had better activity than the standard α-Tocopherol, while in the ABTS•+ assay, it was more active than both standards α- α-Tocopherol and BHA. Both compounds had good antioxidant effects with TR2 being more active than TR22. Both compounds inhibited growth of breast carcinoma cells when compared to the untreated controls after 72 h. Compound TR22 significantly (p < 0.001) inhibited proliferation of both MCF-7 and MDA-MB 231 breast carcinoma cell lines suggesting that acetylation reaction improves inhibition of breast cancer cells growth. On the contrary, TR2 exhibited better inhibitory effect of clone formation than TR22 suggesting that acetylation reduces the activity in this assay. Both compounds inhibited migration of the cancer cells when compared to the untreated control cells and compound TR2 exhibited greater cellular anti-migration effect than TR22 at the same concentration and after the same period of incubation. Molecular docking studies supplemented the results and revealed that TR2 and TR22 had appreciable interactions with tyrosine kinase with negative binding energies suggesting that they are potent receptor tyrosine kinase inhibitors which can impede on cancer progression.