Third strand stabilization of poly(U)·poly(A)* poly(U) triplex by the naturally occurring flavone luteolin: A...

Naturally occurring flavonoid luteolin (LTN) was found to interact with double stranded poly(A).poly(U) and triple stranded poly(U)·poly(A)*poly(U) with association constants of the order of 10⁴M^-1. The association was monitored by various spectroscopic and viscometric techniques. Non-cooperative binding was observed for the association of LTN with two different polymorphic forms of RNA. Intercalation mode of binding was confirmed by fluorescence quenching and viscometric experiments. Thermal melting profiles indicated greater stabilization of the Hoogsteen base paired third strand (∼16°C) compared to Watson-Crick double strand (∼5°C) of RNA by LTN. Since the interaction of naturally occurring small molecules with RNA is an active area of research, this study has led to great openings to explore LTN as RNA targeted therapeutic agent.