A review on the Scorpaena plumieri fish venom and its bioactive compounds

The most poisonous fish species found along the Brazilian coast is the spotted scorpionfish Scorpaena plumieri. Though hardly ever life-threatening to humans, envenomation by S. plumieri can be quite hazardous, provoking extreme pain and imposing significant socioeconomic costs, as the victims may require days to weeks to recover from their injuries. In this review we will walk the reader through the biological features that distinguish this species as well as the current epidemiological knowledge related to the envenomation and its consequences. But above all, we will discuss the challenges involved in the biochemical characterization of the S. plumieri venom and its compounds, focusing then on the successful isolation and pharmacological analysis of some of the bioactive molecules responsible for the effects observed upon envenomation as well as on experimental models. Despite the achievement of considerable progress, much remains to be done, particularly in relation to the non-proteinaceous components of the venom. Therefore, further studies are necessary in order to provide a more complete picture of the venoms chemical composition and physiological effects. Given that fish venoms remain considerably less studied when compared to terrestrial venoms, the exploration of their full potential opens a myriad of possibilities for the development of new drug leads and tools for elucidating the complex physiological processes.

Pharmacological studies on the venomous spotted butterfish (Scatophagus argus Linn) sting extract on experimental animals.

A sting of the fish S. argus, a venomous edible spotted butterfish, produces tremendous local pain, severe swelling, rise of body temperature, throbbing sensation etc. To establish the pharmacological activities of S. argus sting extract, the present investigation, was carried out on experimental animals. The LD50 of extract was found to be 9.3 mg/kg (iv) in male albino mice. The extract showed loss of sensation, urination and salivation in mice. It potentiated pentobarbitone induced sleeping time in male albino mice and produced hypothermia. Extract produced a fall of cat and guinea pig blood pressure, which was completely abolished by mepyramine. It produced a transient reduction of respiratory rate in rat, but decreased respiratory amplitude in cat, which was abolished after vagotomy. On isolated toad heart, the extract increased both the amplitude and rate of contraction. On isolated guinea pig heart, the sting extract decreased both the rate and amplitude of contraction leading to cardiac arrest, but it had no effect on isolated guinea pig auricle. The extract produced a reversible blockade of electrically induced twitch response of isolated chick biventer cervices preparation, but it had no effect on the isolated rat phrenic nerve diaphragm preparation. It produced a slow contractile response on isolated guinea pig ileum, rat uterus and rat fundal strip preparations but produced slow relaxation on isolated rat duodenum preparation. The contractile response on isolated guinea pig ileum and rat fundal strip was antagonised by SC19220. It did not produce any significant cutaneous haemorrhage in mice and did not produce any haemolysis on saline washed erythrocytes. The sting extract significantly increased capillary permeability of guinea pig dorsal flank and produced oedema in mice hind paw.

Purification and properties of a cardioactive toxin, cardioleputin, from stonefish, Synanceja verrucosa

Cardioleputin, a new cardioactive toxin, was purified from a stonefish venom using column chromatographies. The purified toxin was found to be an unstable protein that was susceptible to heat and freeze-thawing. This protein showed to have a molecular size of 46,000 daltons, and its amino acid composition was rich in serine and glycine, but low in basic amino acids. The crude venom induced a sudden drop in blood pressure and heart rate of rats right after administration. Both the blood pressure and heart rate returned to their original values as time elapsed, and thereafter continued to show a gradual decrease. In addition, crude venom actively affected the contractile response and suppressed the heart rate of guinea pig atria. The purified toxin caused irreversible inotropical and chronotropical increases in guinea pig atria. The action of the toxin on the atria was completely different from that of lysolecithin. It might be suggested that the toxin acts on the Ca++ ion channel of the atrial membrane.

Pharmacological actions of the venom of the Indian catfish (Plotosus canius Hamilton).

The venom of the common Indian catfish P. canius Hamilton (locally called 'Kanmagur') was examined for its pharmacodynamic activity. The LD50 of the venom in mice was found to be 3.9 mg/kg (ip). At lower doses, the venom produced a positive inotropic effect on toad and rabbit hearts, while at higher doses it produced cardiac arrest. In the isolated guinea pig auricle, the venom increased the rate and amplitude of contraction. The venom increased rat blood pressure--an action antagonised by alpha-adrenergic blocker (phenoxybenzamine). It reduced the rate and amplitude of rat and guinea pig respiration leading to respiratory arrest and death. The venom did not alter the cutaneous capillary permeability of guinea pig but produced vasoconstrictor effect on rat hindquarter perfusion. It induced contractions in several smooth muscle preparations viz., ileum and colon of guinea pig, fundus, uterus and ileum of rat. On isolated guinea pig ileum, the venom produced contraction which was not antagonised by atropine and mepyramine, but was partially antagonised by methysergide associated with a residual contraction which was abolished by SC 19220, a prostaglandin receptor blocker. The venom produced irreversible blockade of electrically induced twitch response on isolated rat phrenic nerve diaphragm and chick biventer cervicis preparation. Haemolysis was not produced by the venom on mice, guinea pig and human RBC (washed).