Details

Autor(en) / Beteiligte

• Chawla, Raman
• Arora, Rajesh
• Kumar, Raj
• Sharma, Ashok
• Prasad, Jagdish
• Singh, Surendar
• Sagar, Ravinder
• Chaudhary, Pankaj
• Shukla, Sandeep
• Kaur, Gurpreet
• Sharma, Rakesh Kumar
• Puri, Satish Chander
• Dhar, Kanaya Lal
• Handa, Geeta
• Gupta, Vinay Kumar
• Qazi, Ghulam Nabi

Titel

Antioxidant activity of fractionated extracts of rhizomes of high-altitude Podophyllum hexandrum: role in radiation protection

Ist Teil von

• Molecular and cellular biochemistry, 2005-05, Vol.273 (1-2), p.193-208

Ort / Verlag

Netherlands: Springer Nature B.V

Erscheinungsjahr

2005

Quelle

SpringerLink (Online service)

Beschreibungen/Notizen

• Whole extract of rhizomes of Podophyllum hexandrum has been reported earlier by our group to render whole-body radioprotection. High-altitude P. hexandrum (HAPH) was therefore fractionated using solvents of varying polarity (non-polar to polar) and the different fractions were designated as, n-hexane (HE), chloroform (CE), alcohol (AE), hydro-alcohol (HA) and water (WE). The total polyphenolic content (mg% of quercetin) was determined spectrophotometrically, while. The major constituents present in each fraction were identified and characterized using LC-APCI/MS/MS. In vitro screening of the individual fractions, rich in polyphenols and lignans, revealed several bioactivities of direct relevance to radioprotection e.g. metal-chelation activity, antioxidant activity, DNA protection, inhibition of radiation (250 Gy) and iron/ascorbate-induced lipid peroxidation (LPO). CE exhibited maximum protection to plasmid (pBR322) DNA in the plasmid relaxation assay (68.09% of SC form retention). It also showed maximal metal chelation activity (41.59%), evaluated using 2,2'-bipyridyl assay, followed by AE (31.25%), which exhibited maximum antioxidant potential (lowest absorption unit value: 0.0389 +/- 0.00717) in the reducing power assay. AE also maximally inhibited iron/ascorbate-induced and radiation-induced LPO (99.76 and 92.249%, respectively, at 2000 microg/ml) in mouse liver homogenate. Under conditions of combined stress (radiation (250 Gy) + iron/ascorbate), at a concentration of 2000 microg/ml, HA exhibited higher percentage of inhibition (93.05%) of LPO activity. HA was found to be effective in significantly (p < 0.05) lowering LPO activity over a wide range of concentrations as compared to AE. The present comparative study indicated that alcoholic (AE) and hydro-alcoholic (HA) fractions are the most promising fractions, which can effectively tackle radiation-induced oxidative stress.