Inhibitory Effects of Nerium oleander L. and Its Compounds, Rutin and Quercetin, on Parthenium hysterophorus L.

Aqueous and methanol extracts of Nerium oleander L. leaves inhibited seed germination (Germination Percentage, Germination Speed, Germination Value and Peak Value) and early growth (root hair formation, root & shoot lengths of seedlings) of Parthenium hysterophorus L. in a concentration dependent manner. Methanol extracts of white flowered variety showed higher inhibition compared to that of pink flowered variety (at 1:40 dilution of the stock, inhibition was 60% and 23.4% with white and pink, respectively) and had ~5 fold higher levels of Rutin. Rutin and its aglycoside, Quercetin, when mixed with soil affected seed germination, root and shoot lengths of P. hysterophorus, though the effects varied at varying concentrations. These results demonstrate that N. oleander extracts, Rutin and Quercetin are inhibitory to P.hysterophorus. SDS-PAGE analysis of P.hysterophorus seedlings grown in presence of N. oleander aqueous extracts showed an additional prominent band of 42.66 kDa protein.