Nanotechnological exploitation of the antioxidant potential of Hura crepitans L. extract

Hura crepitans L. belongs to the Euphorbiaceae family. It is a tree growing up to 40 m high, characterized by dark, pointed (conical) spines. Its common name “Monkey-no-climb” refers to the characteristic spiny trunk. H. crepitans is known for many ethnomedicinal applications, but also for its toxicity. Indeed, the latex is used as arrow poison and is said to cause ailing teeth to fall out. The milky sap is known to be a poison to fish, due to the presence of huratoxine and hexahydrohuratoxin, two lectins with hemagglutinating activity that inhibit protein synthesis. Huratoxin was demonstrated to be more potent than callicarpone, isolated from Callicarpa candicans (Burm. f.) Hochr., and rotenone, a strong inhibitor of complex I of the mitochondrial respiratory chain. On the other hand, H. crepitans leaves, stem bark, roots, and seeds have several therapeutic applications, which include the treatment of skin diseases, rheumatism, intestinal worms in leprosy. A few studies reported the presence of flavonoids, phenolic acid, carotenoids, terpenes in root, stem bark, and leaf extracts of H. crepitans, especially in aqueous extracts. These compounds are secondary metabolites involved in the defense of plants that play a key role in reducing oxidative stress, which is a prominent cause of various human diseases, such as cancer, neurodegenerative diseases, diabetes, and obesity. Solvent, temperature, and duration of extraction can influence the phytochemical profile and biological activity of plant extracts. The purpose of this study was to improve the knowledge on Hura crepitans L and its antioxidant activity in nanoformulation. Different green extraction methods were applied, varying solvent, temperature, and duration of extraction, which can influence the phytochemical profile and biological activity of plant extracts, and the extracts were fully characterized. Aqueous extracts exhibited a superior antioxidant activity, as indicated by different spectrophotometric tests, and were cytoprotective to HepG2 cells used as model cells. Liquid chromatography–mass spectrometry analyses were performed to identify the secondary metabolites involved in these effects and demonstrated that solvent, duration, and temperature indeed influenced the extraction of polyphenols. Furthermore, the most promising extract, in terms of antioxidant potential, was incorporated into liposomes with the aim of promoting cell interaction and enhancing the antioxidant activity.