Phytochemicals of Roman chamomile: Antioxidant, anti-aging, and whitening activities of distillation residues

The large demand for Roman chamomile essential oil leads to nonnegligible residues in the process of steam distillation. It is an urgent problem to recycle these residues to solve the pollution in the ecological environment and enhance the industrial value. In this study, the components of different fractions extracted from the Roman chamomile residue were analyzed, and their antioxidant, whitening, and anti-aging activities were evaluated. It was found that the crude extract (CE) contained large amounts of polyphenols and flavonoids and displayed obvious antioxidant, whitening, anti-aging activities, and extremely low cytotoxicity. After fractional extraction, polyphenols and flavonoids were largely enriched in the ethyl acetate fraction (EaF), and total polyphenols and total flavonoids increased three- and fourfold, respectively, compared with CE. Especially, the rutin content increased 5.18-fold, quercetin increased 7.29-fold, and luteolin increased 10.58-fold. While chlorogenic acid and <i>p</i>-coumaric acid were mainly enriched in <i>n</i>-butanol fraction (NbF), and increased 2.1- and 2.75-fold than that in CE, respectively. The antioxidant, whitening and anti-aging activities of EaF are significantly higher than those of CE, especially the inhibition for hyaluronidase, elastase were greater than those of epigallocatechin gallate (EGCG), and its inhibitory effects on the tyrosinase and melanin content in B16F10 cells were stronger than those of kojic acid. NbF also showed lower IC₅₀ values than EGCG against hyaluronidase and elastase. These results indicated that the Roman chamomile residue, especially the CE, EaF, and NbF, had excellent antioxidant, whitening, and anti-aging activities and could be a new natural raw material for use in functional cosmetic formulations.