Molluscicidal activity of some plant constituents

Several plant samples were tested for their lethal effects against white garden snail, Theba pisana (Muller), Heliecidae. These samples are Aloe vera, Liliaceae (dried leaves); Allium sativum L., Alliaceae (dried leaves); Chenopodium ambrisoides, Chenopodiaceae (leaves and seeds); Ipomea carnea, Convolvulaceae (leaves, seeds and seed coat); Mangifera indica L, Anacardiaceae (seed kernels); Prunus armeniaca L., Rosaceae (seed kernels);  Punica granatum, Punicaceae (fruit peel) and Zygophyllum album, Zygophyllaceae (areal parts). The tested plant samples were mixed with
wheat bran at ratios; 1:2, 1:1 and 2:1 (w/w). Mortality was differed among the tested plant parts as well as their ratios. P. armeniaca and I. carnea (leaves), followed by C. ambrisoides (leaves), I. carnea (seed-coat) and P. granatum were active with 84.4, 72.2, 65.6, 62.3 and 61.2% mortality, respectively after 14 days at (2:1) ratio. So, seed kernels of P. armeniaca
were separated, extracted with different solvents. The obtained extracts were further fractionated and the produced constituents were checked for their mortal effect. The activity was differed among the separated constituents depending on both concentration and exposure time. The most active constituent caused 100% mortality after 72 hours at a concentration of 10% with LT50 equaled 25.7 (23.7-27.9) hours. GC-MS identification of the active fraction proved that it is enrich in oleic acid, flavanol derivatives, isoquercetrin and cyanogenic glycosides (amygdalin and prunasin). This
study exhibited a positive relation between the molluscicidal activity and the cyanogenic glycosides content.