Radioprotective properties of Hippophae rhamnoides (sea buckthorn)

Abstract

Background - Hippophae rhamnoides, a high altitude habitat plant, has been extremely
used in traditional medicinal practices for treating a variety of ailments. Recently, an
extract (RH-3) prepared from berries of Hippophae rhamnoides has been reported to
exhibit significant radioprotection against whole body lethal irradiation.
Objective - Present study was undertaken to elucidate the DNA binding ability of an
extract (RH-3) prepared from berries of Hippophae rhamnoides and its role in
modulating radiation induced frank and clustered DNA damage.
Method - Agarose gel electrophoresis was employed as method to understand DNA
binding potential and DNA protective ability of RH-3.
Results - RH-3 in a dose dependent fashion interacted with plasmid DNA (pUC18)
reducing the mobility of supercoiled form and increasing the amount of the complex in
the well indicating its ability to interact with plasmid DNA. RH-3 at higher
concentrations (> 0.4 mg/ml) almost completely prevented the migration of supercoiled
form without interfering with mobility of open circular form indicating its ability to
selectively interact with supercoiled form. Studies done with supercoiled or open circular
form also revealed the binding specificity of RH-3 for supercoiled form of plasmid. Both
inhibited radiation induced strand breaks and DNA interaction by RH-3 were found to be
dependent upon pH and the order of efficacy was found to be acidic pH> neutral pH >
alkaline pH. RH-3 in a dose dependent manner inhibited radiation induced frank single,
double strand breaks as well as endonuclease IV detectable abasic sites (clusters) and
maximum reduction was observed at a conce
Conclusion - Results obtained in this study suggest that the ability of RH-3 to interact
with DNA could be playing a significant role in preventing radiation induced DNA
damage.
Key words: Clustered DNA damage, Hippophae rhamnoides, Radioprotection, pUC18,
single strand breaks (ssb); double strand breaks (dsb).