Venoms and Toxins - Current Issue

Olindias sambaquiensis, the most abundant species of jellyfish along the southern coast of Brazil, frequently stings bathers during the summer months, when the occurrence of this species usually reaches a peak.

As jellyfish are rich in protein and carbohydrates, and as these biomolecules could provide a natural defense against stings, this study investigates whether any of the components present in the umbrella of jellyfish species occurring in the south of Brazil can inhibit the nematocyst discharge of the tentacles of O. sambaquiensis.

Sting tests were conducted in humans, with live tentacles of O. sambaquiensis, to evaluate different lyophilized extracts of different exumbrellar jellyfish tissues obtained at different times of the year to determine their capacity to reduce pain and alter skin color.

Of all the species of jellyfish used in this study (O. sambaquiensis, Chiropsalmus quadrumanus and Tamoya haplonema), only the lyophilized extract of the cubozoa C. quadrumanus umbrella showed the capacity to inhibit the pain associated with nematocyst stings.

Tests on a lyophilized extract obtained from organisms caught in summer and winter suggested that the biomolecule responsible for the biological activity is carbohydrate since this biomolecule would signal the recognition of the species. Jellyfish are rich in protein and carbohydrates, and as these biomolecules could provide a natural defense against stings. This study investigates whether any of the components present in the umbrella of jellyfish species occurring in the south of Brazil can inhibit the nematocyst discharge. Of all the species of jellyfish used in this study, only the lyophilized extract of the cubozoa C. quadrumanus umbrella showed the capacity to inhibit the pain associated with nematocyst stings of the O. sambaquiensis. It is suggested that the biomolecule responsible for the biological activity is carbohydrates.

Adansonia digitata has been used as a traditional medicine to treat various diseases including snakebite envenomation.

In this study, the protective and ameliorative potentials of crude methanol extract of Adansonia digitata fruit pulp against crude venom of Naja nigricollis in-vitro and in-vivo were investigated.

The dose-dependent inhibitory studies, pharmacological, histopathological and in vivo studies were conducted using standard methods.

The mean lethal dose of the crude methanolic extract of Adansonia digitata fruit pulp in Wistar rats was > 5,000 mg/kg, while Naja nigricollis venom was 0.89 mg/kg. The anti-lethality effective concentration of the fruit pulp on Naja nigricollis venom was 92.52 mg/ml. Treatment significantly (p < 0.05) inhibited the activities of Naja nigricollis phospholipase A2 and dose-dependently reduced Naja nigricollis venom-induced paw oedema at 1-4 hours post-envenomation. In-vivo, treatment with 250 and 500 mg/kg of Adansonia digitata fruit pulp was protective against the clinical signs and mortality. Serum acetylcholinesterase activities were maintained in the group treated with normal saline and the ameliorative groups but decreased significantly (p < 0.05) in other groups. Brain acetylcholinesterase was high in all the groups by day 1 but was reduced with increasing dose by day 2 in the ameliorative groups only. Adansonia digitata fruit pulp also preserved the histoarchitecture of the brain, heart, liver and spleen from venom-induced pathologies.

Crude methanolic extract of Adansonia digitata fruit pulp possesses good protective and ameliorative neutralization effects on Naja nigricollis venom and could be promising in the management of snakebite envenomation.

Fungi of the genus Lactarius Pers. before the maturation of spores are not damaged by microorganisms, insects, mollusks, and animals. Such resistance correlates with the period when the basidiomes of these fungi are filled with milky juice, which contains substances of various chemical nature that provide their protection.

The aim of our work is to present the results of our recent and previously published studies on the identification and toxicological characteristics of substances available in the milky juice of fungi of the genus Lactarius Pers and used for protection against predator and parasite organisms. The possibility of using these substances to suppress tumor cells is also discussed.

The biological effect of the juice of L. pergamenus, L. quietus, and L. volemus, as well as methylene chloride, extracts obtained from fresh, frozen and dried basidiomes of L. pergamenus was studied. Purification of individual fractions of hexane extract from the basidiomes was performed by chromatography on a silica gel column and their analysis by done by thin layer chromatography and gas chromatography mass spectrometry.

The sesquiterpene aldehydes were shown to be the main component of the chemical protection system of Lactarius. These agents are present in the milky juice of the Lactarius fungi, and they are easily oxidized by oxygen in the air. The milky juice of these mushrooms is also rich in higher fatty acids and phthalates. Phthalates possess an insecticidal effect, while higher fatty acids are capable of forming adducts with sesquiterpenes that provide emulsion stability. Water-soluble substances, in particular, the polyphenol oxidase enzyme, whose activity correlates with the content of milky juice in basidiomes, also play a protective role.

Milky juice of mushrooms of Lactarius Pers. genus is a stable balanced emulsion containing a large number of substances. One part is responsible for the toxic effects on other organisms, while the other part determines the chemical stability of the emulsion. Altogether, they create an effective system of protection of fungi of the Lactarius genus against microorganisms, insects, mollusks, and animals.