Radical Scavenging Activities of Lagerstroemia speciosa (L.) Pers. Petal Extracts and its hepato-protection in CCl4-intoxicated mice

Abstract

Background: Lagerstroemia speciosa (L.) Pers. has medicinal importance. Bioactive phytochemicals isolated from different parts of L. speciosa, have revealed hypoglycemic, antibacterial, anti-inflammatory, antioxidant and hepato protective properties. Despite one report from Philippines detailing the use of L. speciosa as curative for fever and as well as diuretic, there is no experimental evidence about the hepatoprotective activity of the flower extracts.

Methods: Several spectroscopic methods, including GC-MS, were used to characterize phytochemicals present in the petal extract of L. speciosa. Ethanol extract of petals was evaluated for anti-oxidant and free radical scavenging properties by using methods related to hydrogen atom transfer, single electron transfer, reducing power, and metal chelation. This study has also revealed the in vitro antioxidant and in vivo hepatoprotective properties of petal extract against carbon tetra chloride (CCl₄)-induced liver toxicity in Swiss albino mice. Hepatoprotection in CCl₄ -intoxicated mice was studied with the aid of histology and different enzymatic and non-enzymatic markers of liver damage. Cytotoxicity tests were done using murein spleenocytes and cancareous cell lines, MCF7 and HepG2.

Result: GCMS of the extract has revealed the presence of several potential antioxidant compounds, of them γ-Sitosterol and 1,2,3-Benzenetriol (Pyrogallol) were the predominant ones. The antioxidants activities of the flower-extract were significantly higher than curcumin (in terms of Nitric oxide scavenging activity; p = 0.0028) or ascorbic acid (in terms of 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) assay; p = 0.0022). The damage control by the flower extract can be attributed to the reduction in lipid peroxidation and restoration of catalase activity. In vitro cytotoxicity tests have shown that the flower extract did not affect growth and survivability of the cell lines. It left beyond doubt that a flower of L. speciosa is a reservoir of antioxidant and hepatoprotective agents capable of reversing the damage inflicted by CCl₄-intoxication.

Conclusion: Results from the present study may be used in developing a potential hepato-protective health drink enriched with antioxidants from Lagerstroemia speciosa (L.) Pers.

Keywords: Antioxidant activity; CCl4-intoxicated; GC-MS; Hepatoprotective; Lagerstroemia speciosa.

Fig. 1

Free radical scavanging activity of Lagerstroemia flower extract (LFE). a Total antioxidant assay; b DPPH radical scavenging activity; c Singlet oxygen scavenging activity; d Superoxide radical scavenging activity; e Peroxynitrite radical scavenging activity; f Nitric oxide scavenging activity; g (i) and (ii). Fe chelation activity; h Hydroxy radical scavenging; i Hypocholorous radical scavenging activity; j Erythrocyte membrane stabilizing activity; and k Reducing power assay. Paired ‘t’ test was done to interpret significant difference between effect of LFE and the known standard; ***, p < 0.001; **, p < 0.01; and *, p < 0.05

Fig. 2

Hepatoprotective effect of Lagerstroemia flower extract (LFE) or silymarin (SYL) in CCl₄ treated mice. a Protective effect of LFE on catalase (CAT) activity, reduced glutathione (GSH) and Lipid peroxidation (LPO) in CCl₄ treated mice. b Protective effect of silymarin on catalase (CAT) activity, reduced glutathione (GSH) and Lipid peroxidation (LPO) in CCl₄ treated mice group. Comparisons were made with (i) control (CON); (ii) CCl₄ treated (no protection) (CON) for statistical inference (‘t’ test for paired comparison) to interpret significant difference (Data represented as Mean ± SD of six observations. *, p < 0.05, **, p < 0.01 and ***, p < 0.001.)

Fig. 3

Photomicrographs: histological sections of mice liver samples. Pictures were taken under original magnification of 400X. a Liver section from the control group demonstrating normal liver architecture with intact nucleus (IN), and normal sinusoids (NS); b Liver section from CCl₄ induced damaged liver demonstrating highly deformed liver architecture with round congested portal vein (PV), bile duct proliferation (BdP), fatty lesion due to intensive fatty infiltration (FI), sign of necrosis (N), dilated sinusoid (SD), leukocyte infiltration (LI); c Liver section from CCl₄ induced damaged liver demonstrating fibrosis (FB); d Liver section from Silymerin treated group demonstrating improved hepato-cellular architecture with normal sinusoids and intact nucleus (IN); e Liver section from low dose LFE (100 mg/kg of body weight) treated group showing sign of necrosis (N) [of lesser degree compared to the CCl₄ group]; f Liver section from high dose LFE (250 mg/kg of body weight) treated group showing improved liver architecture with normal sinusoids (NS) and intact nucleus (IN)