Multiple extraction conditions to produce phytochemical- and antioxidant-rich Alternanthera sessilis (red) extracts that attenuate lipid accumulation in steatotic HepG2 cells

Abstract

Alternanthera sessilis (red) is an edible herb used by Malaysians to alleviate hyperlipidaemia. This study aimed to produce phytochemical- and antioxidant-rich A. sessilis (red) whole plant extracts using multiple extraction conditions. The lipid-lowering effects of the extracts against steatosis in HepG2 cells were assessed. Ethanolic extracts (100%, 50 °C, 24 h) showed the highest total phenolic content (83.5 mg GAE/g extract) while water extracts (50 °C, 24 h) had the highest extraction yield (20.5%). Ethyl acetate extracts (50 °C, 24 h) showed the highest flavonoids (641 mg RE/g), triterpenoids (46.1 mg UAE/g) and betalains (amaranthin: 72.7 mg/g; betaxanthin: 74.5 mg/g; betanin: 73.1 mg/g). Despite this, the ethanolic extracts showed the highest antioxidant activities (DPPH IC50: 82.6 μg/ml; TEAC: 0.51 mmol TE/g; FRAP: 1.95 mmol Fe2+/g). UHPLC analyses showed the presence of 4 polyphenolic compounds from the extracts; trans-ferulic acid, rutin, quercetin and apigenin. Different concentrations (5–40 μg/ml) of ethanolic, ethyl acetate and water extracts produced at 50 °C, 24 h were selected for cell-based assays. Two assays were used to determine their preventive and ameliorative effects against palmitate-induced lipid accumulation in HepG2 cells. Results indicated that the ethanolic extracts were the most effective at preventing steatosis (intracellular lipid content reduced by 28.3%) while water extracts showed the highest decrease of steatosis (intracellular lipid content reduced by 30%). The results were comparable with the common drug fenofibrate (0.1 mM) for hyperlipidaemia, indicating the potential of this plant's extract to reduce hepatic lipid accumulation.