Taxonomic Patterns in Euphorbiaceae Seed Tocopherol and Tocotrienol Profile: Contribution of Tocochromanols to Antioxidant Potential

While the spurge (Euphorbiaceae) family has played an important role in tocotrienol, tocopherol and other tocochromanol research history, the diversity of these fat-soluble antioxidants in the family remains little-studied. Therefore, seeds of 68 species and 13 genera from the Euphorbiaceae family were investigated. Some connection to taxonomic classification could be observed, but conclusions are severely limited by the number of biological replicates per species. The main tocochromanols were γ-tocopherol and γ-tocotrienol. However, some species had elevated δ-tocopherol content, e.g., Euphorbia marginata (35.88 mg 100 g−1 dry weight–dw). The highest total tocotrienol content (50.96 mg 100 g−1 dw) was observed in γ-tocotrienol-dominated Triadica cochinchinensis. The Mallotus genus was the richest in tocochromanols (up to 100.00 mg 100 g−1 dw) and tocopherol-dominated. This demonstrates the variable dominance of tocopherols or tocotrienols across the family. Tocochromanols constitute the predominant lipophilic antioxidants within the unsaponifiable fraction of Euphorbiaceae seeds. This is consistent with a strong correlation (r = 0.975, p < 0.00001, n = 20) between tocochromanol content and 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity. Tocochromanols contributed only a minor share of antioxidant activity in 96.2% (v/v) ethanolic extracts—below 10%, on average ~2% of the overall activity, depending on species, indicating that other ethanol-extractable phytochemicals have a higher effect on measured antioxidant potential.