A flavone from the ethyl acetate extract of Leea rubra leaves with DNA damage protection and antineoplastic activity

Abstract

Among the major constituents of Leea rubra (Family Vitaceae) leaves, phenolic and flavonoind compounds are most important for therapeutic purposes and the plant parts have been used in traditional medicine to treat several diseases for long. Thus, in order to scientifically confirm the traditional uses of the L. rubra leaves, the present study was designed to investigate the efficacy of the isolated flavones against AAPH induced oxidative damage to pUC19 DNA by gel electrophoresis and antineoplastic activity was evaluated on Ehrlich ascites carcinoma (EAC) bearing Swiss albino mice by evaluating percentage inhibition of cell growth, morphological changes of EAC cells and hematological parameters of the mice. The isolation was carried out by column chromatography and structure was revealed by ¹H-NMR and ¹³C NMR. The result shows that, the isolated compound was identified as myricetin 4'-methoxy-3-O-α-l-rhamnopyranoside based on previously reported data. The isolated flavone effectively inhibited AAPH-induced oxidative damage to DNA; because it could inhibit the formation of circular and linear forms of the DNA. In anti-proliferative assay, 76% growth inhibition of EAC cells was observed as compare to the control mice (p<0.05) at a dose 100 mg/kg body weight. Thus the isolated flavone showed great importance as a possible therapeutic agent in preventing oxidative damage to DNA and the chronic diseases caused by such DNA damage, and can also become important in cancer chemotherapy.

Keywords: Antineoplastic activity; Ehrlich ascites carcinoma; Leea rubra; Oxidative DNA damage.

Graphical abstract

Fig. 1

Proton NMR spectrum of the compound Sz 04.

Fig. 2

Carbon NMR spectrum of the compound Sz 04.

Fig. 3

Chemical structure of the compoundSz-04.

Fig. 4

(a & b). Protective effect of the isolated compound on DNA damage induced by AAPH. Lane-1: Native DNA, Lane-2: DNA + AAPH, Lane-3: DNA + AAPH +20 μg of compound B, Lane-4: DNA + AAPH+30 μg of compound B, Lane-5: DNA + AAPH+ 40 μg of compound B, Lane-6: DNA + AAPH+40 μg of gallic acid. Each lane contains 10 μg DNA. Here, S-form is the super coiled form of plasmid DNA, C-form is the open circular form of plasmid DNA and L-form is the linear form of plasmid DNA.

Fig. 5

(a–c) Fluorescence and (d–f) optical microscopic observation of EAC cells for control mice and treated mice. (a) Represents fluorescence microscopic view of control and (b–c) pure compound treated mice cell whereas (d) express the optical microscopic view of control and (e–f) pure compound treated cells. Normal cell with round shape nucleuses appeared in control group indicated by white arrow in (a); whereas the mice treated with pure compound, condensed nucleus and fragmentation of cells (apoptotic characteristics) were found in (b) and (c) indicated by white and in (e) and (f) by red arrow, respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)