Snake Venom PLA₂s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

Abstract

Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s) are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites.

Anti-obesity Potential of Selected Tropical Plants via Pancreatic Lipase Inhibition

“…Antioxidants interrupt free radical chain oxidation by donating hydrogen from hydroxyl groups to form a stable end product, diphenylpicrylhydrazine (DPPH), which does not initiate or propagate further oxidation of lipids. This causes the purple-coloured DPPH to lose its chromophore and turn it into a yellowish product (α,α-diphenyl-β-picryl hydrazine) [63][64][65].…”

Essential Oils from <i>Mentha piperita, Cymbopogon citratus, Rosmarinus officinalis, Peumus boldus</i> and <i>Foeniculum vulgare</i>: Inhibition of Phospholipase A2 and Cytotoxicity to Human Erythrocytes

“…An aqueous extract of Mandevilla velutina was an effective inhibitor of phospholipase A 2 and inhibited some of its toxic effects, such as hemorrhage [19]. Carvalho et al (2013) [3] reported the importance of plant species in treating snakebites, especially in places that do not have access to serotherapic treatment.…”

“…These substances might also act by inhibiting the action of phospholipases from various sources, both animal and human, exerting anti-inflammatory activities and interfering in processes such as blood coagulation and platelet aggregation. These processes are closely related to the action of eicosanoids generated from arachidonic acid, one of the products of the breakdown of phospholipids [3].…”

Essential Oils from <i>Mentha viridis</i> (L). L. and <i>Mentha pulegium</i> L.: Cytogenotoxic Effects on Human Cells

“…However, there are a few studies on genotoxicity evaluations, the effect on phospholipase or even potential anti-snakebite activities of the essential oils or their constituents, highlighting a wide range of studies to be explored [8] [9] [10].…”