Temporal patterns of fucoxanthin in four species of European marine brown macroalgae

Abstract

Brown seaweeds are a rich source of carotenoids, particularly fucoxanthin, which has a wide range of potential health applications. Fucoxanthin fluctuates within and among seaweeds over time, frustrating efforts to utilise this resource. Thus, we require comprehensive analyses of long- and short-term concentrations across species in field conditions. Here, we used High Performance Liquid Chromatography to compare fucoxanthin content in four brown macroalgae, Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus and Saccharina latissima, monthly for 1 year. F. serratus and F. vesiculosus had significantly higher fucoxanthin content (mg/g), which was highest in Spring (0.39 ± 0.04) and Autumn (0.45 ± 0.04) [mean (± SE)]. Two species, A. nodosum and F. serratus, were collected monthly at the same location for a further two non-consecutive years. For both A. nodosum and F. serratus, a significant interaction effect of seasons and years was identified, highlighting that there is variation in fucoxanthin content among and within species over time. We also show that fucoxanthin content differs significantly among months even within seasons. Therefore, it is not sufficient to assess fucoxanthin in single months to represent seasonality. We discuss how weather, nutrients and reproduction may have driven the seasonal variation, and reveal patterns of fucoxanthin concentration that can provide information concerning its availability for many important medical functions.

Figure 1

Fucoxanthin structure (drawn by AOK author in ChemDraw).

Figure 2

Collection Site at Bangor, Co. Down, Northern Ireland (54° 39′ 58.6″ N 5° 39′ 53.4″ W).

Figure 3

Macroalgal species studied: (A) A. nodosum, (B) F. serratus, (C) F. vesiculosus, (D) S. latissima.

Figure 4

Fucoxanthin content of the four macroalgae (A. nodosum, F. serratus, F. vesiculosus, S. latissima) during four seasons (Autumn, Winter, Spring, Summer). All data were collected during year one (Oct 2015–Sep 2016). Each box and whisker plot shows the median, inter-quartile range, and min/max values. The raw data are shown as points on each plot (n = 9 per species per season).

Figure 5

The fucoxanthin content of Ascophyllum nodosum (A), F. serratus (B), F. vesiculosus (C), and S. latissima (D), over each of the 12 months within year one. Each box and whisker plot shows the median, inter-quartile ranges, and min/max values. The raw data are shown as points on each plot (n = 3 per month).

Figure 6

The fucoxanthin content measured in A. nodosum (A) and F. serratus (B) across four seasons (Autumn, Winter, Spring, Summer), and three years (year one; Oct 2015–Sep 2016, year two; Jan 2018–Dec 2018, year three; Jan 2021–Dec 2021). Each box and whisker plot shows the median, inter-quartile ranges, and min/max values. The raw data are shown as points on each plot (n = 18 per season) .

Figure 7

The monthly and seasonal fucoxanthin content measured across all species sampled in year one (A), year two (B), and year three (C). The mean (± SE) fucoxanthin content is displayed for each month as barplots with error bars. Average monthly temperature measured at the study site is displayed as a red line on each plot. Temperature data from Bangor, Northern Ireland sourced from Met Office UK.