Potential Utilization of a Polysaccharide from the Marine Algae Gayralia oxysperma, as an Antivenom for Viperidae Snakebites.

Worldwide, snakebites have serious implications for human health. The administration of antivenom is the official treatment used to reverse the toxic activities of envenomation. However, this therapy is not efficient to treat the local effects, leading to the amputation or deformity of affected limbs. As such, alternative treatments are needed. Here, we analyze the ability of a polysaccharide from the green marine alga Gayralia oxysperma (Go3) to inhibit the effects of venom from Bothrops jararaca and Lachesis muta. B. jararaca or L. muta venoms were incubated together with sulfated heterorhamnans from Go3, and the in vitro (coagulation, proteolytic, and hemolytic) and in vivo (hemorrhagic, myotoxic, edematogenic, and lethal) activities of venoms were assessed. Additionally, Go3 was injected before and after the injection of venoms, and the toxic activities were further tested. When incubated with the venoms, Go3 inhibited all activities, though results varied with different potencies. Moreover, Go3 neutralized hemorrhagic, myotoxic, and edematogenic activities when injected before or after injection with B. jararaca and L. muta venom. Go3 also blocked the coagulation of plasma in mice caused by the venoms in an ex vivo test. Therefore, Go3 has the potential to be used as antivenom for B. jararaca and L. muta bites, notably exhibiting higher efficacy on L. muta venom.

Acid heteropolysaccharides with potent antileishmanial effects.

The present study investigated in vitro the effects of sulphated heterorhamnan (Go3), iota-/nu-carrageenans (G3d and EHW-I) and arabinogalactan (ARAGAL) polysaccharides on macrophage activation and inhibition of intracellular amastigotes of Leishmania (L.) amazonensis. All the sulphated polysaccharides (Go3, G3d and EHW-I) promoted increased nitric oxide production varying from 71 to 110%. The leishmanicidal activity of all compounds was compared to the inhibition effect of Meglumine Antimoniate at 300µg/mL (∼79%), used as positive control. Inhibition of Leishmania (L.) amazonensis growth was 55% with 5µg/mL of Go3, 50% and 98% to G3d and EHW-I, respectively at 10µg/mL, and 88% with 10µg/mL of ARAGAL. The superoxide anion scavenging activity for the sulphated polysaccharides varied from approximately 30-55% at 10µg/mL. In conclusion, the results of the present study indicate the promising potential of these polysaccharides for the development of new alternative therapeutic agents against leishmaniasis.