Toxicity of chlorophyllin in different wavelengths of visible light against Fasciola gigantica larvae

Photomediated Larvicidal Activity of Pheophorbide a against Cercaria Larvae of Fasciola gigantica

Fasciolosis is a parasitic disease caused by Fasciola gigantica. The freshwater snail Lymnaea acuminata is the intermediate host of F. gigantica which cause endemic fasciolosis in the northern part of India. To investigate larvicidal activity of pure and laboratory extracted pheophorbide a (Pa) against cercaria larvae of F. gigantica, data were analyzed in different spectra of visible light, sunlight, and laboratory conditions. Photostimulation of chlorophyll derivative pheophorbide a (Pa) caused time and concentration dependent larvicidal activity against cercaria larvae of F. gigantica. Larvicidal activity of pure Pa under 650 nm and 400-650 nm (8 h LC₅₀ 0.006 mg/10 mL) was more pronounced than extracted Pa under same irradiations (650 nm LC₅₀ 0.12 mg/10 mL, 400-650 nm LC₅₀ 0.14 mg/10 mL). Lowest toxicity of pure (8 h LC₅₀ 0.14 mg/10 mL) and extracted Pa (8 h LC₅₀ 1.25 mg/10 mL) was noted under 400 nm. Pa was found to be toxic in laboratory conditions also. The results presented in this paper indicate that pheophorbide a possess potential larvicidal activity against Fasciola gigantica larvae in different wavelengths of visible light, sunlight, and laboratory conditions.

Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light

Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries.

Phytotherapy of chlorophyllin exposed Lymnaea acuminata: A new biotechnological tool for fasciolosis control

Phytotherapy of chlorophyllin formulations against Fasciola gigantica infected Lymnaea acuminata under sunlight exposure was highly toxic against redia and cercaria larvae. Binary combinations (1:1 ratio) of chlorophyllin (CHL) + freeze dried cow urine (FCU) were more toxic against cercariae (8 h LC₅₀: 9.6 mg L^- 1) than single treatment with chlorophyllin (8 h LC₅₀: 12.6 mg L^- 1) in sunlight. The larvicidal activity of sunlight exposed CHL against rediae (8 h LC₅₀: 13.5 mg L^- 1) and cercariae (8 h LC₅₀: 12.6 mg L^- 1) was more pronounced than laboratory conditions CHL treatment (rediae- 8 h LC₅₀: 305.9 mg L^- 1; cercariae- 8 h LC₅₀: 765.4 mg L^- 1). Larvicidal activity of FCU was less than CHL and CHL + FCU against both redia and cercaria. Chlorophyllin and its formulations were more toxic against redia and cercaria larvae in sunlight than laboratory conditions. CHL and its different formulations may be used as potent larvicides against Fasciola gigantica larvae. Chlorophyllin formulations will be economical, ecologically sounder and their use in aquatic environment will be safe.

Chlorophyllin Bait Formulation and Exposure to Different Spectrum of Visible Light on the Reproduction of Infected/Uninfected Snail Lymnaea acuminata

Fasciolosis is a waterborne disease, caused by Fasciola species. Snail Lymnaea acuminata is an intermediate host of these flukes. Control of snail population is major tool in reducing the incidences. Variation in light intensity and wavelength caused significant changes in reproduction pattern of snails. Maximum fecundity was noted with bait containing carbohydrate (starch, 468 ± 0.10/20 snails) or amino acid (serine, 319 ± 0.29/20 snails) as attractant. Sublethal feeding of chlorophyllin bait with starch or serine attractant to infected and uninfected snails caused significant reduction in fecundity, hatchability, and survivability. These significant changes are observed in snails exposed to different spectral band of visible light and sunlight. Maximum fecundity of 536 ± 2.0 and minimum of 89.3 ± 0.4 were noted in snails not fed with bait and exposed to sunlight and red spectral band, respectively. There was complete arrest in the fecundity of infected and uninfected snails and no survivability of uninfected snails after 48 h feeding with bait containing chlorophyllin + attractant. Minimum hatchability (9.25 ± 0.5) was noted in red light exposed, chlorophyllin + starch fed infected snails and hatching period of bait fed snails was prolonged. Conclusively, chlorophyllin bait and red light reduce reproduction capacity in snails.