Effect of cycloart-24-en-3beta-ol from Euphorbia royleana latex on neuroenzyme AChE and oxidative metabolism of freshwater fish, Channa punctatus.

Cycloart-24-en-3beta-ol isolated from Euphorbia royleana latex possesses potent piscicidal activity against freshwater predatory fish Channa punctatus. Their short as well as long-term exposure causes significant (P<0.05) time and dose-dependent reversible alteration in the oxidative metabolism of the fish Channa punctatus Cycloart-24-en-3beta-ol also shifts fish respiratory pathway, inhibits energy production and AChE activity reversibly may be advantageous for their use as environmentally safe piscicide for controlling the predatory fish C. punctatus population from carp culture ponds.

Biochemical stress response in freshwater fish Channa punctatus induced by aqueous extracts of Euphorbia tirucalli plant.

Piscicidal activities of aqueous extracts of Euphorbia tirucalli were very well established, but their ultimate mode of action on fish metabolism was not yet known. Exposure of fishes over 24h or 96h to sub-lethal doses (40% and 80% of LC(50)) of aqueous extract of E. tirucalli stem-bark and latex, significantly (P<0.05) altered the level of total protein, total free amino acids, nucleic acids, glycogen, pyruvate, lactate and activity of protease, alanine aminotransferase, aspartate aminotransferase, acetylcholinesterase and cytochrome oxidase enzyme in liver and muscle tissues of freshwater fish Channa punctatus. The alterations in all these biochemical parameters were significantly (P<0.05) time- and dose-dependent. After 7d of withdrawal of treatment of 80% of LC(50) of E. tirucalli extracts shows that there was a partial recovery in the levels of glycogen but nearly complete recovery in total protein, total free amino acids, pyruvate, lactate, nucleic acids level and activity of protease, aspartate aminotransferase, alanine aminotransferase, acetylcholinesterase and cytochrome oxidase enzyme in both the tissues of fish. Thus aqueous extracts of E. tirucalli adversely affect respiratory pathway of fish and cause energy crisis during stress by suppressing ATP production. The reversibility of the action of the aqueous extracts would be an additional advantage in their use.

Alterations in carbohydrates and the protein metabolism of the harmful freshwater vector snail Lymnaea acuminata induced by the Euphorbia tirucalli latex extract.

To know the short- as well as long-term effect of aqueous latex extracts of Euphorbia tirucalli on carbohydrate and protein metabolism, the snail Lymnaea acuminata was exposed to sublethal doses of 0.37 and 0.55 mg/L for a 24-h and 0.20 and 0.31 mg/L for a 96-h exposure period. Significant (P<0.05) alterations in the glycogen, pyruvate, lactate, total protein, and free amino acid level, as well as in the activity of enzyme lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase, and alanine aminotransaminase were observed in the nervous, hepatopancreatic, and ovotestis tissues of the freshwater vector snail L. acuminata exposed to sublethal doses of E. tirucalli latex extract. The alterations in all biochemical parameters were significantly (P<0.05) time and dose dependent. After the 7th day of the withdrawal of treatment, there was significant (P<0.05) recovery in glycogen, pyruvate, lactate, total protein, and the free amino acid level and in the activity of the lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase and alanine aminotransaminase enzymes in all three of the studied tissues of the snail, which supports the view that the plant product is safe for use as a molluscicide for the control of harmful freshwater vector snails in the aquatic environment.

Toxic effect of stem bark and leaf of Euphorbia hirta plant against freshwater vector snail Lymnaea acuminata.

The aqueous stem bark and leaf extracts of plant Euphorbia hirta (family-Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40% and 80% of LC50) of aqueous stem bark and leaf extracts of this plant also significantly (P<0.05) alter the levels of total protein, total free amino acid, nucleic acids (DNA and RNA) and the activity of enzyme protease and acid and alkaline phosphatase in various tissues of the vector snail Lymnaea acuminata in time and dose dependent manner. Euphorbia hirta (family-Euphorbiaceae) commonly known as Dudhi, is a common medicinal plant of India, which is used in variety of diseases i.e. cough, asthma, colic, dysentery, genito urinary diseases.

Toxicological effect and biochemical alterations induced by different fractions of Euphorbia royleana latex in freshwater harmful vector snail Lymnaea acuminata.

Laboratory evaluation was made to assess the molluscicidal activity of different fractions of Euphorbia royleana (Family- Euphorbiaceae) latex obtained through sephadex gel column against freshwater snail Lymnaea (Radix) acuminata Lamarack. This snail is the vector of liver fluke, Fasciola hepatica Linnaeus and Fasciola gigantica Cobbold, which causes endemic fascioliasis in cattle and livestock. The toxic effect of the different fractions was time dependent and fifth fraction obtained through benzene: ethyl acetate (5:5) had maximum molluscicidal activity against Lymnaea acuminata. There was a significant negative correlation between LC values and exposure periods thus increase in exposure time, the LC50 value of V fraction of Euphorbia royleana latex was decreased from 14.28 mg/l (24 hr) to 9.28 mg/l (96 hr) against Lymnaea acuminata. After exposure to sub-lethal concentrations of this fraction there were significant time and dose dependent alterations observed in pyruvate, lactate levels, ALAT, AAT, AChE and cytochrome oxidase enzyme activities in different body tissues of Lymnaea acuminata. It is proposed that the fifth fraction of E. royleana latex can be used as a molluscicide for controlling the harmful snail population from aquatic ecosystem without any harm due to their reversible toxic action.

Toxic and sub-lethal effects of oleandrin on biochemical parameters of fresh water air breathing murrel, Channa punctatus (Bloch.).

Active compound oleandrin extracted from Nerium indicum (Lal Kaner) leaf has potent piscicidal activity. The piscicidal activity of oleandrin on freshwater fish C. punctatus was both time and dose dependent. Exposure to sub-lethal doses of oleandrin for 24hr and 96hr to fish caused significant alteration in the level of total protein, total free amino acid, nucleic acid, glycogen, pyruvate, lactate and enzyme protease, phosphatases, alanine aminotransferase, aspartate aminotransferase and acetylcholinesterase activity in liver and muscle tissues. The alterations in all the above biochemical parameters were also significantly time and dose dependent. The results show a significant recovery in all the above biochemical parameters, in both liver and muscle tissues of fish after the 7th day of the withdrawal of treatment. Toxicity persistence test of oleandrin on juvenile Labeo rohita shows that fish seed of common culturing carp can be released into rearing ponds after three days of oleandrin treatment. It supports the view that the oleandrin is safer and may be useful substitute of other piscicides for removing the unwanted freshwater fishes from aquaculture ponds.

Control of common freshwater predatory fish, Channa punctatus, through Nerium indicum leaf extracts.

The diethyl ether, chloroform, acetone and methanol extract of Nerium indicum leaf were evaluated for their piscicidal activity against common freshwater air breathing predatory fish Channa punctatus. The rank of order of toxicity (LC50) of the leaf extract was, diethyl ether extract (17.34 mg/l)>acetone (40.01 mg/l)>chloroform (40.61 mg/l)>and methanol (106.37 mg/l). There was a significant negative correlation between LC50 values and exposure periods. Thus increase in exposure period, LC50 decreases from 17.34 mg/l (24 h) to >13.58 mg/l (96 h) in the diethyl ether extract. Similar trends were also observed in acetone, chloroform and methanol extracts. Exposure of sub-lethal doses (40% and 80% of LC50) of the diethyl ether extract of N. indicum leaf (which has maximum piscicidal activity) for 24 or 96 h caused significant alteration in the level of total protein, total free amino acid, nucleic acid, glycogen, pyruvate, lactate and activity of enzyme protease, phosphatases, alanine aminotransferase, aspartate aminotransferase and acetylcholinesterase in liver and muscle tissue. The alterations in all the above biochemical parameters were significantly (P<0.05) time and dose dependent. There was a significant recovery in all the above biochemical parameters, in both liver and muscle tissues of fish after the seventh day of the withdrawal of treatment. Thus, the leaf extracts of N. indicum have potent piscicidal activity against fish C. punctatus and also significantly affect both aerobic and anaerobic pathway of respiration in fish.