Orris root diversity and quality assessment: Multivariate analysis of phytochemicals and antioxidant properties

Iris germanica rhizome known as orris root, has been used as flavoring, tea, spice and also herbal drug, around the world. The more terpenoid irone structures considered as the better quality in orris aroma. In this research, a multivariate analysis showed a high diversity in the essential oil (EO), total content of phenol (TPC), flavonoid (TFC), tannin (TTC) and carotenoid (TCC) and antioxidant activity (DPPH and FRAP assays) of 33 samples of Iris germanica, released in a breeding project including parents and hybrids, along with one commercial sample. Based on the results of GC-MS analysis, 59 compounds were identified, 17 of which were major compounds. Among the studied samples, the highest amount of α-irone (25.52%) and β-irone (37.98%) compounds was observed in P5, one of the parent sample. Mean comparison of phytochemical characteristics showed that OPRC104, a hybrid sample which is the richest source of TPC (173.29 mg GAE/g DW) and TTC (6.12 mg TA/g DW) and antioxidant activity (DPPH: 282.20 mg TBHQ/g DW) among all samples. The results of the present study showed that in breeding programs of Iris germanica, parent 5 (P5) can be used to increase irone structures and hybrid 104 (OPRC104) can be used to achieve the highest amount of phenolic compounds and antioxidant activity.