Studies on the post-coital contraceptive mechanisms of crude extract of Sri Lankan marine red algae, Gelidiella acerosa

An overview on red algae bioactive compounds and their pharmaceutical applications

Objectives To review red algae bioactive compounds and their pharmaceutical applications. Content Seaweed sources are becoming attractive to be used in health and therapeutics. Among these red algae is the largest group containing bioactive compounds utilized in cosmetic, pharmaceutical, food industry, manure and various supplements in food formula. Various significant bioactive compounds such as polysaccharides (aginate, agar, and carrageenan), lipids and polyphenols, steroids, glycosides, flavanoids, tannins, saponins, alkaloids, triterpenoids, antheraquinones and cardiac glycosides have been reported in red algae. The red algae have rich nutritional components Different polysaccharides of red algae possess the antiviral potential namely agarans, carrageenan, alginate, fucan, laminaran and naviculan. Sulfated polysaccharides and carraginans of red algae are rich source of soluble fibers which can account for antitumor activities depending upon chemistry of various secondary metabolites and metabolism of cell line. Flavons-3-ols containing catechins from many red algae block the telomerase activity in colon cancer cells. Contraceptive agents were tested from red algae as a source for post-coital. Lectin of red algae showed pro-healing properties and anti-ulcerogenic activities. Carragenates from red algae also conferred a positive influence on diabetes. Red algae depicted a reducing effect on plasma lipids and obesity. Porphyran from red alga can act as anti-hyperlipidemic agent also reduces the apolipoprotein B100 via suppression of lipid synthesis in human liver. Summary The polyphenolic extracts of Laurencia undulate, Melanothamnus afaqhusainii and Solieria robusta extract show anti-inflammatory effects against multiple genera of devastating fungi. Antioxidants such as phlorotannins, ascorbic acids, tocopherols, carotenoids from red algae showed toxicity on some cancer cells without side effects. Red algae Laurencia nipponica was found insecticidal against mosquito larvae. Red algae fibers are very important in laxative and purgative activities. Gracilaria tenuistipitat resisted in agricultural lands polluted with cadmium and copper. Outlook In the recent decades biotechnological applications of red algae has been increased. Polysaccharides derived from red algae are important tool for formulation of drugs delivery system via nanotechnology.

Isolation of a non-steroidal contragestative agent from Sri Lankan marine red alga, Gelidiella acerosa

This study reports the isolation of a non-steroidal contragestative agent from the Sri Lankan marine red alga, Gelidiella acerosa. One-hundred grams of MeOH-CH2Cl2 (1:1) crude extract of G. acerosa was initially partitioned into hexane, CH2Cl2 and EtOAc, respectively, using the modified Kupchan scheme. At each separation step, all the resulting fractions were tested for contragestative effects in pregnant rats. The fertility was assessed in terms of the number of viable implants following oral administration of fractions (co-precipitated with polyvinylpyrrolidone), on day 1 through day 7 of pregnancy. The hexane fraction with highest activity was subjected to gel filtration through Sephadex LH-20, vacuum liquid chromatography over TLC-grade silica, two open-column chromatography runs over silica gel (60-120 mesh), and HPLC to isolate the active component. Nuclear magnetic resonance and infrared spectroscopic analysis revealed that the contragestative agent of G. acerosa is a sphingosine derivative.