In the present study Hypnea valentiae was collected along the shore of Mandapam and was identified and
authenticated. To analyse the methanol extract of marine red macro alga species H. valentiae using Gas chromatography-Mass
spectrometry (GC-MS) and in vitro antibacterial activity. Gas chromatography and mass spectrometry analysis of seaweed
extract injected with instrument GC-MS-QP 2010 [SHIMADZU] and antibacterial activity of human pathogenic bacteria. The
methanol extracts of Hypnea valentiae was identified 27 bioactive compounds which were major compound such Hexadecanoic
acid-methylester, 13-Docosenamide, (Z) and Eicosane (RT, 21.07, 34.46, 16.51; 29.10%, 10.27%, 10.24%) Cholest-5-en-3-ol, 24-
propylidene-, (3á)-, 9-Octadecenoic acid (Z)-, methyl ester (CAS) (RT39.09, 24.38; 9.00%, 8.07%) Hexadecanoicacid (CAS) -
Methyl tetradecanoate (RT 21.89, 17.04; 4.74%, 3.30%). In India, seaweeds have been utilized since the ancient times as source
of human food, animal feed, fertilizer, as well as herbicides.
