Evaluation of UV-sunscreen mycosporine-like amino acids (MAAs) in two economically important red macroalgae from Peru

Mycosporine-like amino acids (MAAs) are UV-absorbing, multifunctional metabolites with increasing biotechnological relevance. This study provides the first comprehensive characterization of MAAs profiles in two commercially important Peruvian red macroalgae, Chondracanthus chamissoi and Gracilariopsis lemaneiformis, cultivated in Pisco (Ica, Peru). Seasonal (spring vs. summer) and life-stage (gametophyte vs. tetrasporophyte) differences were analysed using HPLC–DAD for targeted quantification and UHPLC–HRMS/MS coupled with feature-based molecular networking (FBMN) for untargeted metabolite discovery. Both species were confirmed as high MAAs producers (> 2 mg g^-1 DW) and shared the same set of 13 MAAs, although their relative abundances varied by species, season, and life stage. Chondracanthus chamissoi accumulated up to 3.39 mg g^-1 DW and exhibited a SH-dominant profile (shinorine (SH), palythine (PA) and asterina-330 (AS)), complemented by ten additional low-abundance MAAs detected by FBMN. Gracilariopsis lemaneiformis reached higher total concentrations (up to 3.69 mg g^-1 DW) and displayed a broader primary-MAAs repertoire, including porphyra-334 (PR), together with nine secondary metabolites detected at trace levels. Seasonal forcing produced pronounced summer maxima MAAs total concentration in both species, although the magnitude of induction was substantially greater in G. lemaneiformis - consistent with an inducible, habitat-dependent photoprotective strategy - whereas C. chamissoi showed a more constitutive response aligned with persistent intertidal UV exposure. Life-stage effects were also evident, tetrasporophytes of both species generally accumulated higher total MAAs levels and exhibited richer MAAs profiles. FBMN revealed several previously unreported MAAs in both taxa, expanding the known chemical diversity of Peruvian Rhodophyta. Collectively, these findings demonstrate strong environmental and ontogenetic modulation of MAAs biosynthesis and highlight both species - particularly G. lemaneiformis - as promising, sustainable sources of natural UV-protective compounds for cosmetic, pharmaceutical, and biomedical applications.