sentence: Although the availability of NA sources is limited , the seeds of several plant species reportedly contain relatively large amounts of NA within storage lipids ( e.g ., Cardamine graeca , Malania oleifera , A. truncatum , Lunaria annua , Borago officinalis , and Tropaeolum speciosum ) ( Bettger et al ., 2001 ; Wang and Wang , 2005 ; Guo et al ., 2009 ; Taylor et al ., 2009 ; Yang et al ., 2018 ) .