[Preparation of five ginkgolic acid monomers and their molluscicidal effects against Oncomelania hupensis].

OBJECTIVE: To investigate the molluscicidal activities of the ginkgolic acid(GA) monomers isolated and purified from GAs. METHODS: Five monomers of GAs from the sarcotesta of Ginkgo biloba. were extracted by petrol ether, separated by silica gel column chromatography, purified by semi-prepared reversed-phased HPLC, and identified by LC-MS analysis. The molluscicidal activities of GAs and their monomers against Oncomelania hupensis were determined as referring to the WHO guidelines for laboratory molluscicidal test. RESULTS: The five purified ginkgolic acid monomers were GA(13:0), GA(15:0), GA(15:1), GA(17:1) and GA(17:2), with a side chain of 13, 15, 17 alkyl or ethylenic radicals res pectively on their benzene loop. The five monomer proportions to the total GAs were 17.6%, 3.2%, 52.3%, 23.3% and 3.6% respectively. The order of molluscicidal activities for the five monomers was as follows: GA(13:0)>GA(15:1)>GA(15:0)>GA(17:1)>GA(17:2), and their LC50 for snails was 20.79 mg/L, 22.28 mg/L, 33.76 mg/L, 51.89 mg/L, and 59.10 mg/L respectively after immersion for 24 hours. Two monomers, GA(13:0), and GA(15:1) inhibited the snails' climbing up significantly. CONCLUSION: The molluscicidal activities of GAs may be dependent on the monomer's structure with different number of carbon molecules and double-bonds on the side carbon-chain. The two monomers, GA(13:0) and GA(15:1), are mainly responsible for the molluscicidal activities of GAs and both effectively inhibit snails' climbing up as well. GA(15:0) also shows certain molluscicidal activity.

[Preliminary survey on concentration of indoor allergens derived from dust mites in residential homes in Shanghai].

OBJECTIVE: To investigate the level of indoor dust mite allergens in residential homes in Shanghai. METHODS: The allergenic proteins, Dff F3 and Der f III (well known allergen) from the whole culture extract of Dermatophagoides farinae were purified by chromatography and sedimentation techniques. Allergic activities of both proteins were identified by skin prick test and RAST. After preparation of specific IgG anti-Dff F3, anti-Der f III, and extraction of indoor allergens from 200 indoor dust samples collected from residential homes, the allergen concentration was measured by sandwich ELISA. Allergen level was expressed in geometric mean and range, the analysis of variance (ANOV) was used to determine the level of significance between groups. RESULTS: Dff F3 and Der f III were demonstrated strongly allergic activities, which can be highly recognized with IgE from sera of the mite-allergic patients with asthma. In the sampled 200 homes, the proportion of homes with Dff F3 level of >10 microg/g was 57.0%, 29.5% for group of 2-10 microg/g, and 13.5% for group of <2 microg/g. The proportion of homes with Der f III level of >10 microg/g was 53.5%, 32.0% for group of 2-10 microg/g, 14.5% for group of <2 microg/g. CONCLUSION: Selected residential homes in Shanghai were found more likely to have high level of dust mite allergens. Dff F3 was identified as the stronger allergic fraction.