Lignin from oil palm empty fruit bunches: Characterization, biological activities and application in green synthesis of silver nanoparticles.

Lignin was extracted from oil palm empty fruit bunches under four different conditions. The lignin samples were characterized and employed in the green synthesis of silver nanoparticles. Two-dimensional HSQC NMR analysis showed that lignins extracted under more aggressive conditions (3.5% acid, 60 min) exhibited less signals and thus, presented a more degraded chemical structure. Additionally, those lignins obtained under harsh conditions (3.5% acid, 60 min) exhibited higher antioxidant capacity than those obtained under mild conditions (1.5% acid, 20 min). Formation of lignin-mediated silver nanoparticles was confirmed by color change during their synthesis. The surface plasmon resonance peaks (423-427 nm) in UV-visible spectra also confirmed the synthesis of AgNPs. AgNPs showed spherical shape, polycrystalline nature and average size between 18 and 20 nm. AgNPs, in suspension, presented a negative Zeta potential profile. Lignin was assumed to contribute in the antioxidant capacity exhibited by AgNPs. All AgNPs presented no significant differences on the disk diffusion antimicrobial susceptibility test against E. coli. The minimum inhibitory concentration of HAL3-L AgNPs (62.5 µg·mL-1) was better than other physicochemically produced AgNPs (100 µg·mL-1).

Pentose-rich hydrolysate from oil palm empty fruit bunches for ß-glucan production using Pichia jadinii and Cyberlindnera jadinii.

Pentose-rich hydrolysate obtained from dilute acid pretreatment of oil palm empty fruit bunches was successfully consumed by pentose-consuming yeasts: Cyberlindnera jadinii (Cj) and Pichia jadinii (Pj). Nitrogen supplementation and no additional detoxification step were required. Pj produced 5.87 g/L of biomass using a C/N ratio of 14 after 120 h of fermentation, with xylose consumption of 71%. Cj produced 10.50 g/L of biomass after 96 h of fermentation with C/N ratio of 11.5, with maximum xylose consumption of 85%. ß-glucans, high value-added macromolecules, were further extracted from the yeast biomass, achieving yields of 3.1 and 3.0% from Pj and Cj, respectively. The isolated polysaccharides showed a chemical structure of ß-(1,3)-glucan with residues of other molecules. Additionally, ß-(1,6) branches seems to have been broken during isolation process. Further studies assessing ß-glucans production at industrial scale should be carried out looking for nitrogen sources and optimizing the ß-glucan isolation method.

Protective Effect of the Sulfated Agaran Isolated from the Red Seaweed Laurencia aldingensis Against Toxic Effects of the Venom of the Snake, Lachesis muta.

Snakebite is a serious occupational hazard affecting mainly rural populations of tropical and subtropical developing countries. Lachesis muta (Bushmaster) bites are extremely serious but are rarely reported in the literature. Bushmaster envenomings are characterized by intense local pain, edema, neurotoxicity, hypotension, local hemorrhage, and dramatic systemic alterations. Antivenom treatment has regularly been used for more than a century; however, it fails to neutralize local tissue damage and hemorrhage, leading to morbidity or disabilities in victims. Thus, the production and clinical use of antivenom must be improved. The present work characterizes, for the first time, a sulfated polysaccharide from the red seaweed, Laurencia aldingensis, including its neutralizing effect on some toxic activities of L. muta venom. Chemical and spectroscopic analyses showed that L. aldingensis produces sulfated agarans with the A-units partially C-2 sulfated or 6-O-methoxylated presetting the B-units in the cyclized (3,6-anhydro-α-L-galactose) or in the non-cyclized form (α-L-galactose). The latter is significantly substituted by sulfate groups on C-6. In vitro and in vivo assays showed that this sulfated agaran inhibited hemolysis, coagulation, proteolysis, edema, and hemorrhage of L. muta venom. Neutralization of hemorrhagic activity was also observed when the agaran was administered by different routes and after or before the venom injection. Furthermore, the agaran blocked the edema caused by a phospholipase A2 isolated from the L. muta venom. Experimental evidence therefore indicates that the sulfated agaran of L. aldingensis has potential to aid antivenom therapy of accidents caused by L. muta venom and may help to develop more effective antivenom treatments of snake bites in general.

Sulfated Galactan from Palisada flagellifera Inhibits Toxic Effects of Lachesis muta Snake Venom.

In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse the evolution of all the toxic effects is performed by injection of antivenom. However, such therapy does not effectively neutralize tissue damage or any other local effect, since in most cases victims delay seeking appropriate medical care. In this way, alternative therapies are in demand, and molecules from natural sources have been exhaustively tested. In this paper, we analyzed the inhibitory effect of a sulfated galactan obtained from the red seaweed Palisada flagellifera against some toxic activities of L. muta venom. Incubation of sulfated galactan with venom resulted in inhibition of hemolysis, coagulation, proteolysis, edema and hemorrhage. Neutralization of hemorrhage was also observed when the galactan was administered after or before the venom injection; thus mimicking a real in vivo situation. Moreover, the galactan blocked the edema caused by a phospholipase A2 isolated from the same venom. Therefore, the galactan from P. flagellifera may represent a promising tool to treat envenomation by L. muta as a coadjuvant for the conventional antivenom.