Chemical composition and inhibitory effects of water extract of Henna leaves on reactive oxygen species, DNA scission and proliferation of cancer cells

From the centuries, Lawsonia inermis L. (Henna) is utilized in traditional health care system as a medicinal and cosmetic agent. The present study was intended to assess antiradical, DNA protective and antiproliferative activity of water extract of Lawsonia inermis L. leaves (W-LI). Antioxidant activity was estimated using various in vitro assays such as DPPH, ABTS, superoxide anion radical scavenging, FRAP, deoxyribose degradation and DNA protection assay. Growth inhibitory effects of W-LI were assessed using MTT assay against different cancer cell lines viz. HeLa, MCF-7, A549, C6 and COLO-205. From the results of antioxidant assays, it was found that W-LI quenched DPPH and ABTS cation radicals with IC(50) value of 352.77 µg/ml and 380.87 µg/ml respectively. It demonstrated hydroxyl radical scavenging potential of 59.75 % at highest test dose of 1000 µg/ml in deoxyribose degradation assay. The results of FRAP assay showed that W-LI also possesses significant reducing activity. Extract inhibited hydroxyl radical induced pBR322 plasmid DNA strand scission, thus conferring DNA protection. Growth inhibition of various cancer cell lines was achieved to the varying extent on treatment with W-LI. Further, it was observed that activity was quite promising against colon cancer COLO-205 cells (GI(50) 121.03 µg/ml). HPLC profiling of W-LI revealed the presence of different polyphenolic compounds such as ellagic acid, catechin, quercetin, kaempferol etc. which might be contributing towards antioxidant and cytotoxic activity. The present study demonstrated that polyphenols rich W-LI extract from leaves of L. inermis possesses ability to inhibit oxidative radicals and cancer cells proliferation.