Phycochemical analyses and pharmacological activities of seven macroalgae of Arabian Sea (Northern coast line).

Seaweeds have been used as nutraceuticals because of certain metabolites present in some species including polyphenols. Seven species of seaweeds collected from the Karachi coast were screened for the first time both for phycochemical analysis and pharmacological activities. The phycochemicals quantified included phenols, flavonoids, tannins and saponins. Melanothamnus afaqhusainii showed the highest content of phenols (2.16mg GAE/g) while highest flavonoids were observed in Coelarthrum muelleri (4.59mg RE/g). Tannins were found in low amounts while saponins were observed as major constituents among the seaweeds ranging from 1.34-3.47% in Sargassum swartzii and Codium flabellatum, respectively. Saponins were not analysed in Rhodophyta due to gel formation. Pharmacological screening revealed analgesic and anti-inflammatory effects. Both the methods of analgesic activities have shown significant increase in reaction time when methanol extracts were used. The reason for delayed anti-inflammatory activity of Solieria robusta and C. muelleri was found correlating with its gel forming ability. While Cystoseira indica and C. flabellatum exhibited highly significant effect from 1st to 5th h. Results suggested that selected seaweeds had potential in combating both acute and chronic inflammation and pain and hence can be used for therapeutic efficacy.