Borage oil: Tocopherols, sterols and squalene in farmed and endemic-wild Borago species

Abstract

Endemic Borago species contain notably high amounts of γ-linolenic acid (GLA, 18:3n6), the main bioactive fatty acid of borage oil. However, little is known about the occurrence of nutritionally relevant phytochemicals in seed oil of such plants. This work was designed to test the occurrence of important phytochemicals (tocopherols, sterols and squalene) in the seed oil of Borago species. To this end, seeds of endemic-wild and farmed Borago species were collected and analyzed. All compounds were analyzed by HPLC-diode array detector, while sterol and squalene peaks were confirmed using a LC–MS device and a library software. The highest amounts of tocopherols were found in two endemic Borago species: B. pygmaea and B. morisiana, with 514 and 296 mg/100 g oil, respectively. Squalene was predominant in B. officinalis collected in Tunisia and B. morisiana (3.9 mg/100 g seeds). The main sterols were Δ5-avenasterol, campesterol, and β-sitosterol, which were especially high in B. morisiana and B. pygmaea, with 107 and 102 mg of total sterols by100 g of seeds, respectively. The latter species are noteworthy GLA producers. The study suggested that oils from the endemic species are more nutritionally advantageous than those from the common cultivated borage (B. officinalis) and other current sources.