Antioxidant activity and cytotoxicity of Jerusalem artichoke tubers and leaves extract on HaCaT and BJ fibroblast cells

BACKGROUND: Extracts from plants, rich in antioxidants may be used as active ingredients of many preparations, mainly due to their antioxidant, regenerative and anti-aging properties. The work involved a comprehensive evaluation of the Jerusalem artichoke (Helianthus tuberosus L.) leaf and tuber extract as a multifunctional raw material. METHODS: The plant extracts were prepared by using ultrasound-assisted extraction method (UAE).The content of total phenolic and flavonoid compounds of extracts were determined spectrophotometrically using the Folin-Ciocalteu method and aluminium nitrate nonahydrate, respectively. Antioxidant activity of extract was analyzed using DPPH free radical scavenging assay and the effect of the investigated extracts on the proliferation of keratinocytes (HaCaT) and fibroblasts (BJ) was measured. To detect of intracellular reactive oxygen species level in tested cells, the fluorogenic dye H(2)DCFDA was used. In the next step, the ability of obtained extracts to regulate the expression of genes (SOD-1, Nox-4) involved in oxidative stress in cells was evaluated. RESULTS: As a result of the conducted research, it was shown that leaf extract exhibit a higher content of phenols and flavonoids comparing to tuber extracts (5.07 and 7.14 fold higher, respectively). The opposite trend was observed after proliferation assay with Neutral Red test. It was shown that tuber extract in all applied concentrations (25–500 μg·ml(− 1)) had a positive effect on fibroblast growth. The leaf extract showed proliferative activity only for the smallest tested concentrations (25–100 μg·ml(− 1)). Similar trends were observed for HaCaT cells. The distinct effect of leaves and tuber extract on the generation of ROS was observed in HaCaT cells. In the present study, it was shown that tuber and leaf extracts may increase the expression of the ROS SOD-1 inactivating enzyme gene in the fibroblast cell line. There were no significant differences in gene expression of the ROS Nox-4 producing enzyme. In the case of keratinocytes, the opposite effect was observed. CONCLUSIONS: The study suggest that Jerusalem artichoke leaves and tubers extracts affect the cell proliferation and can alter the expression of genes related to oxidative stress.