Bioguided Isolation and in-Silico Analysis of Hep-G2 Cytotoxic Constituents From Laurus nobilis Linn. Cultivated In Egypt

Document Type : Original Article

Authors

1 Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.

2 Department of Biochemistry, Faculty of Agriculture, Zagazig University, Zagazig, Egypt

Abstract

The air dried leaves of Laurus nobilis cultivated in Egypt were extracted by petroleum ether followed by methylene chloride then ethyl acetate and finally methanol. The preliminary cytotoxic screening of these extracts against Hep-G2 using vinblastine sulfate (IC50= 2.93 μg/ml) as standard showed that petroleum ether, methylene chloride and ethyl acetate extracts exhibited strong cytotoxic activity (IC50= 10.6, 5.96 and 3.80 μg/ml, respectively) while the methanolic extract showed moderate activity (IC50= 23.2 μg/ml). Bio-guided chromatographic isolation of L. nobilis extracts resulted in isolation of seven compounds identified as 1-tricosanol (1), reynosin (2), protocatechuic acid (3), vincetoxicoside B (4) and vitexin (5). chemical structures have been established on the basis of physical, chemical and spectroscopic methods (UV, IR, MS, 1H-NMR, 13C-NMR and HSQC) in addition to comparison with literature data and /or authentic samples. Reynosin (2) showed the most potent cytotoxic activity against Hep-G2 (IC50= 4.98 μg/ml) among other isolated compounds, while vitexin (5) showed the lowest activity (IC50= 219 μg/ml). Other compounds showed moderate to weak activity. The isolated compounds were docked to caspase3 to reveal their possible cytotoxic mechanism of action on the enzymatic level. Protein fraction obtained after 0.5 hr hydrolysis with papain showed moderate cytotoxic activity (IC50= 200 μg/ml) and that obtained after 3.5 hr hydrolysis exhibited strong antioxidant action (45 % inhibition at a concentration of 200 μg/ml using DPPH assay).

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