Antioxidant, Phenolic, Flavonoid, and Mineral Content of L. officinalis and Its Cytotoxic Effect on Human Embryonic Kidney (Hek-293) Cells

Abstract

Cherry laurel (L. officinalis) is a well known natural product and folk medicine in the Black Sea region of Turkey. The aim of this study was to investigate the antioxidant effect, polyphenolic, and mineral content of cherry laurel and the cytotoxic effect of its methanolic extraction on human embryonic kidney cells. The total phenolic content of L. officinalis was found to be 1.28 mg GAE/g, while the flavonoid content was 1.26 mg RE/g. The DPPH scavenging activity was 118.76 μg/g. Total antioxidant capacity was found to be 3.54 mM/100 g and in HPLC analysis only chlorogenic acid (101 μg/g) could be detected, but cyanidin-3-glucoside chloride, resveratrol, vanillic acid, (+)-catechin, and (−)-epicatechin could not. The highest mineral content was found in magnesium levels (46.10 ± 0.57 μg/g), but also contained selenium (9.90 ± 0.78 μg/g), silver (4.46 ± 0.27 μg/g), lead (1.34 ± 0.08 μg/g), zinc (1.31 ± 0.11 μg/g), and copper (0.66 ± 0.05 μg/g). Trace amounts of manganese (0.17 ± 0.02 μg/g) and mercury (0.08 ± 0.01 μg/g) were found in aqueous extraction of L. officinalis but in ethanolic and methanolic extractions these elements could not be detected. In all elements there was a statistically significant increase in water extraction of L. officinalis. Cobalt could not be detected in any of the extractions. The IC₅₀ concentration of L. officinalis on Hek-293 cells was found to be 370 mg/mL. As a conclusion, L. officinalis is rich in chlorogenic acid and is a good antioxidant fruit. The high antioxidant activity, phenolic and flavonoid content, and mineral content are mostly used to decrease oxidative stress; however, it should not be forgotten that antioxidants may also have pro-oxidant effects and should be investigated more on healthy and unhealthy cells.