Antioxidant mediated protective effect of Parthenium hysterophorus against oxidative damage using in vitro models

Abstract

Background: Parthenium hysterophorus L. (Asteraceae) is a common weed occurring throughout the globe. In traditional medicine its decoction has been used for treatment of many infectious and degenerative diseases. This work was therefore designed to assess the phytochemical constitution of P. hysterophorus flower and root extracts and to evaluate their reducing power, radical scavenging activity as well as protective efficacy against membrane lipid damage.

Methods: Dried flower and root samples were sequentially extracted with non-polar and polar solvents using Soxhlet apparatus. The phytochemical screening was done using standard chemical methods and thin layer chromatography. Total phenolic content was determined spectrophotometrically. Reducing power and hydroxyl radical scavenging activity assays were used to measure antioxidant activity. Protection against membrane damage was evaluated by inhibition of lipid peroxidation (TBARS assay) in rat kidney homogenate.

Results: Flavonoids, terpenoids, alkaloids and cardiac glycosides were present in all the extract. The total phenol contents in flower and root extracts were found to be in the range 86.69-320.17 mg propyl gallate equivalent (PGE)/g and 55.47-253.84 mg PGE/g, respectively. Comparatively better reducing power was observed in hexane fractions of flower (0.405) and root (0.282). Benzene extract of flower and ethyl acetate fraction of root accounted for appreciable hydroxyl radical scavenging activity (75-77%). Maximum protection against membrane lipid peroxidative damage among flower and root extracts was provided by ethanol (55.26%) and ethyl acetate (48.95%) fractions, respectively. Total phenolic content showed positive correlations with reducing power and lipid peroxidation inhibition (LPOI) % in floral extracts as well as with hydroxyl radical scavenging activity and LPOI % in root extracts.

Conclusion: Study established that phytochemicals present in P. hysterophorus extracts have considerable antioxidant potential as well as lipo-protective activity against membrane damage.

Figure 1

Thin layer chromatogram of P. hysterophorus extracts. (A) Flower and (B) Root extracts. The extracts dissolved in respective solvents were chromatographed in solvent system containing chloroform (163): ethyl acetate (63): formic acid (25) followed by spraying of FCR for visualization of phenolic contents. Arrows indicate phenolic spots. Numbers indicate specific extracts (1-hexane, 2-benzene, 3-chloroform, 4-ethyl acetate, 5-acetone, 6-ethyl alcohol, 7-aqueous extracts).

Figure 2

Reducing power of P. hysterophorus flower extracts. Extracts were prepared in hexane (HX), benzene (BZ), chloroform (CH), ethyl acetate (EA), acetone (AC), ethanol (ET) and water (AQ) as described in materials and methods section. Reducing power was measured at different concentration of extracts (200–1000 μg/ml). Butylated hydroxytoluene (BHT) was used as control. The results are expressed as mean ± SD of three replicates.

Figure 3

Reducing power of P. hysterophorus root extracts. Extracts were prepared in HX, BZ, CH, EA, AC, ET and AQ as described in materials and methods section. Reducing power was measured at different concentration of extracts (200–1000 μg/ml). BHT was used as control. The results are expressed as mean ± SD of three replicates.

Figure 4

Lipo-protective efficacy of P. hysterophorus flower extracts in tissue (rat kidney) homogenate. Percent lipid per-oxidation inhibition (% LPOI) activity of flower extracts (BZ, EA, ET and AQ) at a concentration of 2 mg/ml was assessed as an indicator to protect per-oxidative damage of membrane lipids in rat kidney homogenate. Butylated hydroxylanisole (BHA) was used as control. The results are expressed as mean ± SD of three replicates.

Figure 5

Lipo-protective efficacy of P. hysterophorus root extracts in tissue (rat kidney) homogenate. % LPOI activity of root extracts (BZ, EA, ET and AQ) at a concentration of 2 mg/ml was assessed as an indicator to protect per-oxidative damage of membrane lipids in rat kidney homogenate. BHA was used as control. The results are expressed as mean ± SD of three replicates.