Novel report of the phytochemical composition from Fraxinus excelsior pollen grains

Abstract

In this research, we investigated the phytochemical profiles for two models of aqueous (Aq) and methanolic (Me) pollen extracts of F. excelsior from three pollination periods from hermaphrodite flowers (H) of polygamous and male flowers of pure male (M) in order to identify their constituent compounds. Pollens of both phenotypes H and M were collected during three pollination periods and were analyzed by light and scanning electron microscopy (LM/SEM). The total phenolic content (TPC) and flavonoids content (TFC) was measured using Folin-Ciocalteu and aluminum chloride (AlCl3) methods, respectively. Antioxidant activities were evaluated using ferric reducing antioxidant power (FRAP) and scavenging free radical DPPH• and ABTS•+. GC-FID and GC/MS were used to identify the chemical composition of essential oils. There was a significant difference (P < 0.001) between the means of TPC for M and TFC for the H. Comparison of H and M antioxidant activities showed that DPPH (IC50) to be (2.977 ± 0.117 μM) during the second pollination period of M and (4.877 ± 0.021 μM) for first period of H. The majority of the compounds identified were linalool (35.42%) from the monoterpenoides in H and Delta-cadinene (43.22%) belonging to the sesquiterpenes in M. We concluded that there is a significant difference between the H and M compounds in pollen at different periods.