Molluscicidal activity of Morus nigra against the freshwater snail Lymnaea acuminata

The molluscicidal activity of Morus nigra fruit, bark and leaf powder against the snail Lymnaea acuminata was time and concentration dependent. Toxicity of fruit powder (96h LC50: 166.92 mg/L) was more pronounced in comparison to bark powder (96h LC50: 173.17 mg/L) and leaf powder (96h LC50: 173.69 mg/L). Ethanolic extracts of M. nigra fruit, bark and leaf was more toxic than their other organic solvent extracts. The molluscicidal activity of ethanolic extract of M. nigra fruit powder (24h LC50: 116.23 mg/L) was more effective than the ethanolic extract of bark powder (24h LC50: 154.41 mg/L) and leaf powder (24h LC50: 139.80 mg/L). The 96h LC50 of column-purified fraction of M. nigra fruit powder was, 10.03 mg/L whereas that of bark and leaf powder was 8.69 mg/L and 4.97 mg/L, respectively. Column and thin layer chromatography analysis demonstrates that the active molluscicidal component in M. nigra is quercetin (96h LC50: 1.11 mg/L), apigenin (96h LC50: 1.92 mg/L) and morusin (96h LC50: 2.12 mg/L), respectively. Co-migration of quercetin (Rf 0.49), apigenin (Rf 0.51) and morusin (Rf 0.52) with column-purified fruit, bark and leaf of M. nigra on thin layer chromatography demonstrates same Rf value. The present study indicates that M. nigra may be used as potent source of molluscicides against the snail Lymnaea acuminata.