Effect of Eucalyptus globulus oil and Ricinus communis methanolic extract as potential natural molluscicides on the reproductive biology and some antioxidant enzymes of the land snail, Theba pisana

Abstract

This study was conducted to investigate the effects of Eucalyptus globulus oil and methanolic extract of Ricinus communis seeds on the reproductive biology of the land snail Theba pisana. For this purpose, the snails were exposed to different concentrations of these plant extracts for six weeks. Rates of oviposition, hatching percentages, reproductive hormones and the histological structures of the hermaphrodite gland were estimated. Antioxidant enzymes were also estimated. The obtained results revealed that all tested concentrations of both tested natural products exerted hazardous effects on exposed snails. The mean egg number/snail treated with 2% E. globulus and R. communis were significantly decreased to 22 and 14 eggs respectively compared to 79 eggs for control. The hatching rates were dramatically decreased with increasing concentrations of both products. 2% of R. communis extract caused highly significant decrease in the activities of CAT, SOD, GST and MDA antioxidant enzymes while the same concentration of Eucalyptus oil resulted in elevations of CAT and SOD activities and significantly decreased GST and MDA activities. Levels of reproductive hormones were greatly disrupted and the histological structures of hermaphrodite acini as well as various developmental stages of spermatogenesis and oogenesis of treated snails were strictly spoiled.