Bioactive constituents from the edible seaweed (Rhodophyta).

CONTEXT

The marine macroalga, , holds significant commercial potential due to its culinary uses among various ethnic groups in Hawai'i and its success in aquaculture.

OBJECTIVE

To investigate the chemical components and potential medicinal properties of .

MATERIALS AND METHODS

Dried, ground was sequentially extracted with three solvents: ethyl acetate, methanol, and -butanol. Chromatographic procedures were sequentially applied, leading to the isolation of several compounds. Structure determination of these compounds was performed using spectroscopic methods. The isolated compounds were then assessed through several assays.

RESULTS

A total of 11 compounds were isolated and identified: two nucleosides ( and ), a cytosine analog (), five saturated long-chain fatty acids (-), cholesterol (), and two of its derivatives (-) were isolated. Compounds and displayed promising antimicrobial activity against , both exhibiting MIC values of 8 μg/mL, and methicillin-susceptible , with MIC values of 32 and 64 μg/mL, respectively. Furthermore, using a cell culture model, compounds , , and exhibited significant anti-inflammatory effects as indicated by their inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production, with IC values ranging from 50.2 to 60.8 µM. These compounds also effectively inhibited the generation of reactive oxygen species (ROS)/reactive nitrogen species (RNS) in RAW 264.7 mouse macrophage cells with IC values of 55-73.7 µM without inducing cytotoxicity. Compounds also exhibited mild cytotoxicity against the non-small cell lung cancer cell line A549, with compound eliciting the strongest response (IC 86.1 µM).

CONCLUSIONS

This study uncovered a diverse array of constituents from . Notably, compounds and , which feature peroxide side chains, show significant promise as lead compounds for the development of novel anti-inflammatory and antimicrobial agents.