title: Podophyllum hexandrum Offers Radioprotection by Modulating Free Radical Flux: Role of Aryl-Tetralin Lignans.
abstract: We have evaluated the effect of variation in aryl-tetralin lignans on the radioprotective properties of Podophyllum hexandrum. Two fractionated fractions of P. hexandrum [methanolic (S1) and chloroform fractions (S2)], with varying aryl-tetralin lignan content were utilized for the present study. The peroxyl ion scavenging potentials of S1 and S2 were found to be comparable [i.e. 45.88% (S1) and 41% (S2)] after a 48 h interval in a time-dependent study, whereas in a 2 h study, S2 exhibited significant (P < 0.05) antioxidant activity in different metal ion + flux states. In the aqueous phase, S2 exhibited non-site-specific reactive oxygen species scavenging activity, i.e. 73.12% inhibition at 500 mug ml(-1). S1 exhibited 58.40 +/- 0.8% inhibition (at 0.025 mug ml(-1)) of the formation of reactive nitrite radicals, comparable to S2 (52.45 +/- 0.825%), and also showed 45.01% site-specific activity (1000 mug ml(-1)), along with significant (P < 0.05) electron donation potential (50-2000 mug ml(-1)) compared to S2. Such activities of S1 could be attributed to the significantly (P < 0.05) higher levels of podophyllotoxin beta-d-glucopyranoside (16.5 times) and demethyl podophyllotoxin glucoside (2.9 times) compared with S2. Together, these findings clearly prove that aryl-tetralin lignan content influences the radiation protective potential of the Podophyllum fractions to a great extent.
authors.forename: Raman
authors.initials: R
authors.lastname: Chawla
authors.forename: Rajesh
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authors.lastname: Arora
authors.forename: Shikha
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authors.lastname: Singh
authors.forename: R K
authors.initials: RK
authors.lastname: Sagar
authors.forename: Rakesh Kumar
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authors.lastname: Sharma
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authors.lastname: Kumar
authors.forename: A
authors.initials: A
authors.lastname: Sharma
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authors.initials: RP
authors.lastname: Tripathi
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authors.initials: SC
authors.lastname: Puri
authors.forename: H A
authors.initials: HA
authors.lastname: Khan
authors.forename: A S
authors.initials: AS
authors.lastname: Shawl
authors.forename: P
authors.initials: P
authors.lastname: Sultan
authors.forename: Tej
authors.initials: T
authors.lastname: Krishan
authors.forename: G N
authors.initials: GN
authors.lastname: Qazi