Halimione portulacoides (L.)

Maciel, Elisabete, Lillebø, Ana, Domingues, Pedro, Costa, Elisabete da, Calado, Ricardo & Domingues, M. Rosário M., 2018, Polar lipidome profiling of Salicornia ramosissima and Halimione portulacoides and the relevance of lipidomics for the valorization of halophytes, Phytochemistry 153, pp. 94-101 : 97

2.2. Lipid profile of Halimione portulacoides

Halimione portulacoides exhibited nineteen different FA ( Table 1 ). The FA profile was characterized by a high percentage of PUFA (∼60%), in particular, omega-3 (n -3) FA (nearly 45%). The most abundant fatty acids contained 16 and 18 carbon atoms, and C18:3 n -3 (43.5%), which was the main FA present in H. portulacoides . The FA 16:0 was the second most abundant FA (19.2%), being the most represented SFA. MUFA accounted for ∼12% of total FA, with oleic acid C18:1 n- 9 being the most abundant (∼10% of the total pool of FAs).

The LC− MS− based approach employed allowed the identification of 160 PL molecular species distributed over five classes: 69 PC, 43 PE, 20 PA, 21 PG and 7 PI molecular species; three glycolipid classes: SQDG, MGDG and DGDG, and one glycosphingolipid HexCer in the lipid extracts of H. portulacoides . The distribution of acyl chains differed between PL classes, as shown in Table 4. The main PC molecular species were PC 16:0/18:2 and PC 16:1/18:1 (m/z 756.556), PC 16:0/18:1 (m/ z 760.585), PC 18:1/18:3 and PC 18:2/18:2 (m/z 782.566) and PC (18:1/18:1), PC (18:0/18:2) and PC (16:2/20:0) (m/z 786.601). Odd-chain FA's were found in some PC molecular species, such as C17:0, C19:0, C21:0, as well as molecular species with very long chain FA (PC 18:3/24:0; PC 18:1/24:1). The main PE molecular species in H. portulacoides lipid extracts were identified at m/z 714.505, identified as PE 16:0/18:2 and PE 16:1/18:1, and at m/z 738.505 assigned as PE 18:2/ 18:2 and PE 18:1/18:3. Some of the molecular species contained odd chain FAs such as PE 18:2/21:0 and PE 17:2/24:0. In the PA class, the molecular species identified were esterified to FA with 16 and 18 carbon atoms. The main molecular species in the PA class were PA 16:0/18:2 at m/z 671.464 and PA 18:2/18:2 and 18:1/18:3 at m/z 695.464. The acyl composition of PG ranged from 14 to 20 carbon atoms. PG 16:0/18:3 and PG 16:1/18:2 (m/z 743.485) and PG 16:0/ 18:2 and 16:1/18:1 (m / z 745.499) were the most abundant molecular species. In this same class a molecular specie with C18:4 (PG 16:0/18:4) was detected at m / z 741.468. The molecular species of the PI class had fatty acyl groups with 16 and 18 carbon atoms and with 0–3 double bonds, as was observed for PA class. The most abundant molecular specie was found at m/z 833.515, corresponding to PI 16:0/18:2.

The analysis of the lipid extracts of H. portulacoides revealed three glycolipid classes: SQDG, MGDG and DGDG and one glycosphingolipid, HexCer. In total, 39 molecular species were identified: 18 SQDG, 10 MGDG, 8 DGDG and 3 HexCer ( Table 5 ). The acyl composition of GL molecular species ranged from 14 to 20 carbon atoms and 0 to 3 double bonds. The details of all GL molecular species that were identified are shown in Table 3 . The main SQDG molecular species was SQDG 18:3/ 16:0 at m/z 815.497, followed by SQDG 16:0/16:0 at m/z 793.512 and SQDG 18:3/18:2 at m/z 839.496. The most abundant molecular species in MGDG observed in LC− MS was the MGDG 18:3/18:3 at m/z 792.558. Only one MGDG molecular species with odd-chain FA was observed, the MGDG 119:2/18:3 at m/z 808.553. The fatty acyl chains of DGDG comprised 16 or 18 carbon atoms. The main molecular species was DGDG 18:3/18:3 at m/z 954.611. No molecular species with odd-chain FA were identified in this class.

The analysis of HexCer showed the presence of both di- and trihydroxy long-chain bases. The long chain bases were C18, while the fatty acids were hydroxylated. The most abundant molecular species was HexCer t 18:1/h24:0 at m/z 844.684.