Mangroves: A Potent Source of Polysaccharides
Mangroves possess a number of chemical defense mechanisms against various physical, chemical, and biological stresses. Chemical metabolites of mangroves have been used traditionally by indigenous people for centuries, but, until recently, the chemistry of these natural products has remained poorly dened (Bandaranayake, 2002). Mangroves are well known for containing high phenolic compounds such as tannins, which offer protection to the plant against pest and parasitic damages (Kathiresan and Veera Ravi, 1990; Veera Ravi and Kathiresan, 1990). Mangroves are proven for their potent biological activities against human, animal, and plant
pathogens (Premanathan et al., 1992). It is known that the accumulation of low-molecular-weight organic solutes such as sugars, some amino acids, and quaternary ammonium compounds are involved in the adaptation to abiotic stresses (Hibino et al., 2001). Mangroves have also been reported to synthesize and accumulate various chemicals such as aliphatic alcohols and acids, amino acids, alkaloids, carbohydrates, lignins, polysaccharides, carotenoids, hydrocarbons, fatty acids, lipids, pheromones, phorbol esters, phenolics, steroids, troterpenes, tannins and other terpenes, and related compounds (Bandaranayake, 2002). Most mangrove species produce a lot of natural products, such as antioxidants and terpenoids, to modulate physiological activities, including membrane permeability to salt and other solutes (Oku et al., 2003; Parida et al., 2004; Vijayavel et al., 2006) in addition to providing chemical defense.