Extracts from Lupinus albescens: antioxidant power and antifungal activity in vitro against phytopathogenic fungi.

Fungi are considered the most damaging microorganisms in agriculture. The indiscriminate use of chemical treatments in agricultural products causes the development of pest resistance and affects human health. An alternative to synthetic fungicides is the use of natural products such as plant extracts for the management of fungal diseases in plants. Extracts from different parts of Lupinus albescens (roots, stalks, leaves, and flowers) were obtained by extraction using supercritical carbon dioxide (CO2) or compressed liquefied petroleum gas (LPG). Thereafter, the antioxidant activity of each extract was measured, and the antifungal activity in vitro of extracts was evaluated against Fusarium oxysporum and Fusarium verticillioides. For a concentration of 5000 mg/L, the half maximal inhibitory concentration (IC50) ranged from 29.25 μg/mL to 192.96 μg/mL. Antifungal tests showed that all matrices presented inhibitory effect against both fungi tested. The extracts obtained from roots by CO2 and LPG presented 70.1% and 65.1% inhibition against F. oxysporum, and 67.8% and 61.2% inhibition against F. verticillioides, respectively. These results suggest that the extracts obtained from L. albescens by extractions using supercritical CO2 and compressed LPG might be a potential source of antioxidants and natural fungicides.