Biocompounds and Bioactivities of Selected Greek Boraginaceae Seeds

Abstract

The seeds of Boraginaceae species constitute a source of γ-linolenic acid (GLA, 18:3n-6)-rich oils, mainly those of Borago officinalis. However, there are many wild unexplored Boraginaceae taxa that are potentially GLA producers. This work scrutinizes the seeds of several Greek Boraginaceae species for fatty acids (FAs), phenolic compounds, antioxidant activity, and in vitro antiproliferative activity against HT-29 colorectal cancer cells. The FA profiles were checked by GC-FID, and GLA (FA% of total FA) highlights in Symphytum bulbosum (26.2), S. creticum (23.2), and Lithodora zahnii (17.4). The total FA content ranged from 9.2 in Alkanna methanaea to 27.3 g/100 g of seeds in Alkanna corcyrensis. The antioxidant activity of the water/methanol extracts, evaluated by the ABTS and DPPH methods, was in line with other GLA producer seeds. Phenolic acids were analyzed by HPLC-DAD and LC-MS, and rosmarinic acid ranged from 160.2 in S. bulbosum to 479.7 mg/100 g in L. zahnii. The MTT assay showed dose- and time-dependent inhibitory effects of the water/methanol extracts against HT-29 cancer cells, especially those of C. major and L. zahnii (GI50 of 600 and 375 μg/mL for 72 h-exposed cells). This work constitutes the first approach to evaluate the seeds of Boraginaceae taxa from Greece as functional oil providers.