Aim:
To identify the lipid composition of linseed and establish a more reliable qualitative evaluation method for lipid-rich herbal medicines
Linseed and its oil are commonly consumed health products around the world, for their gluten-free fiber and abundant omega-3 essential fatty acid. It is also widely used in Chinese Medicine for the prevention of constipation.
Fatty acids are selected as the assay markers in both Chinese Pharmacopoeia and European Pharmacopoeia of linseed and its oil, respectively. The issue of using fatty acids as markers is that their contents in linseed are rather low. Triglycerides, triesters of fatty acids and glycerol, are the major group of compounds in linseed extract. However, due to the varied structures of triglycerides, not all of them are commercially available.
In this study, the structures and identities of the major triglycerides in linseed are determined by RPHPLC-Q-TOF-MS/MS. Ion fragmentation mechanisms of triglyceride chemical reference standards are also studied to help identify those reference standards are unavailable. Eleven triglycerides are identified in linseed extract. The next move is to quantify the fatty acids and triglycerides in linseed and apply the evaluation method to other lipid-rich herbal medicines.