# In Vitro Antiviral Activity of Red Algae Extracts from Chondracanthus teedei var. lusitanicus and Osmundea pinnatifida Against Coxsackievirus A12 and a Lentiviral Vector

## TL;DR

This study shows that red algae extracts from two species collected in Portugal can inhibit the replication of two viruses in laboratory tests.

## Contribution

The study identifies specific red algae extracts with potent antiviral activity against Coxsackievirus A12 and a lentiviral vector in vitro.

## Key findings

- Extracts from Chondracanthus teedei and Osmundea pinnatifida inhibited viral replication at non-cytotoxic concentrations.
- O. pinnatifida showed the strongest antiviral effects against both viruses tested.
- The extracts interfered with multiple stages of the viral life cycle and induced an antiviral state in cells.

## Abstract

Infectious diseases remain a major global health challenge, underscoring the need for safe and accessible antiviral therapies. Natural products, particularly marine macroalgae, are promising sources of bioactive compounds with antiviral properties. This study evaluated the antiviral activity of extracts from two red algae collected along the Portuguese coast: two life stages (tetrasporophyte and female gametophyte) of Chondracanthus teedei var. lusitanicus and the algae Osmundea pinnatifida. Antiviral effects were assessed against Coxsackievirus A12 (CVA12) and a lentivirus (LV) vector model. Extracts from both algae inhibited viral replication in vitro at non-cytotoxic concentrations. The tetrasporophyte extract of C. teedei exhibited virucidal activity against CVA12, and the results are consistent with interference with multiple stages of the viral life cycle, while also inducing an antiviral state in HEK-293T cells against LV infection. The female gametophyte extract affected early stages of CVA12 and LV infection and showed potential virucidal activity. O. pinnatifida demonstrated the strongest antiviral effects against both viruses. These findings highlight the antiviral potential of these red algal extracts and warrant further in vivo evaluation.