Detrital leaves from seagrass of the Cymodoceaceae family were assayed for biologically active molecules that have commercial as well as societal benefits.

We focused on L-chiro-inositol, a very rare natural occurring cyclitol, and chicoric acid, a polyphenolic compound, in which both applications were found in the nutraceutical segment.

Six species of seagrass belonging to the genera Syringodium, Cymodocea and Halodule were collected from their native habitat. The L-chiro-inositol content of the crude aqueous extracts prepared from different batches of Cymodocea nodosa flotsam was measured by quantitative ¹H-NMR spectroscopy. High concentrations were found with values ranging from 22.2 to 35.0 mg.g^-1 plant dw. The presence of L-chiro-inositol in the tropical species C. rotundata, C. serrulata, Syringodium isoetifolium, and Halodule pinifolia was also characterized by qualitative NMR. The chicoric acid content of crude aqueous methanolic extracts prepared from C. rotundata, C. serrulata, S. isoetifolium, and Halodule pinifolia was determined by quantitative HPLC-DAD. The values found ranged from 0.39 to 6.15 mg.g^-1 dry weight. Chicoric acid was unambiguously identified as the major phenolic in S. isoetifolium, and Halodule pinifolia, while it was found in mixture with flavonol derivatives in C. rotundata and C. serrulata. Flavonol derivatives are also of interest for their bioactivity.

Considering the demonstrated therapeutic applications of L-chiro-inositol and chicoric acid, their high value on the nutraceutical market, and their rare occurrence in the plant kingdom, their presence in Syringodium, Cymodocea and Halodule detrital leaves makes this abundant biomass of interest for dietary and pharmaceutical applications.

These results show that there is a real potential for harvesting beachcast Cymodoceacea.