银杏外种皮提取物杀灭钉螺效果的研究

目的 　观察银杏外种皮石油醚提取物（主要成分为银杏酸，含量为64%）、槟榔碱及两药伍用杀灭钉螺效果及对斑马鱼急性毒性。 方法 取7～8螺层、活力强的钉螺，用银杏外种皮干粉、水提取物和石油醚提取物3种制剂以及银杏外种皮石油醚提取物与槟榔碱伍用，采用WHO“杀螺剂实验室终筛方法”中的浸泡法，进行浸杀钉螺试验、钉螺上爬试验以及斑马鱼急性毒性试验。 3项试验均以氯硝柳胺为对照。 结果 　银杏外种皮3种制剂随浸泡时间延长浸杀效果明显提高。 其中，石油醚提取物浸杀效果较好， 浸泡24 h LC₅₀和LC₉₀分别为0.65 mg/L和5.50 mg/L，48 h 分别为0.07 mg/L和0.85 mg/L； 72 h钉螺死亡率近100%。与槟榔碱伍用, 浸杀效果明显提高, 浸泡24 h 银杏外种皮石油醚提取物LC₅₀和LC₉₀分别为0.26 mg/L 和0.56 mg/L，较银杏外种皮石油醚提取物单药LC₅₀降低60%，LC₉₀降低90%(P值均<0.05)。2.50 mg/L银杏外种皮石油醚提取物24 h总上爬率为10%；两药伍用，其银杏外种皮石油醚提取物0.16 mg/L上爬率仅为8%，提高了其抑制钉螺上爬效果。1倍LC₉₀和2倍LC₉₀浓度的银杏外种皮石油醚提取物，斑马鱼存活时间分别为24 h和10 h；伍用后，24 h斑马鱼在2倍LC₉₀浓度中未见死亡，48 h内死亡率为50%，伍用对斑马鱼急性毒性较低。 结论 银杏外种皮石油醚提取物有较好的灭螺效果，是具有研究价值的灭螺植物。

Study on Molluscicidal Effect of the Extracts from Sarcotesta of Ginkgo biloba

OBJECTIVE: To observe the molluscicidal activity and the fish acute toxicity of the molluscicides extracted from Ginkgo biloba sarcotesta by benzinum (EGSB) (with major component of ginkgolic acid), arecoline (ARE) and their combination. METHODS: Oncomelania hupensis snails were immersed in different concentrations of dry powder sarcotesta of Ginkgo biloba (DPGB), extract of Ginkgo biloba sarcotesta by water (EGSW) and EGSB by WHO recommended method for molluscicide screening to observe the molluscicidal activity, and also the inhibiting effect on the snails' climbing-up as well as acute toxicity to Brachydanio rerio. Niclosamide was used as control. RESULTS: The three extractions from Ginkgo biloba all showed molluscicidal activity, with EGSB as the best. Its 24 h LC50 and LC90 were 0.65 mg/L and 5.50 mg/L, and the 48 h LC50 and LC90 were 0.07 mg/L and 0.85 mg/L, respectively. The combination of EGSB and ARE showed better effect than EGSB alone. Its 24 h LC50 and LC90 were 0.26 mg/L and 0.56 mg/L respectively, a sharp decrease by 60% and 90% compared to EGSB (P<0.05). Under the concentration of 2.50 mg/L of EGSB, the rate of snails' climbing-up was 10%, while under the concentration of 0.16 mg/L of the EGSB+ARE combination, the rate was 8%. The inhibition on the snails' climbing-up of the combination was stronger than EGSB. The fish survived for 24 h and 10th respectively at the concentration of 1 x LC90 and 2 x LC90 of EGSB. Under the concentration of 2 x LC90 of the combination, only 50% of the fish died and no fish died at the concentration of 1 x LC90. The toxicity of the combination was lower than EGSB alone. CONCLUSION: EGSB shows an adequate molluscicidal activity and it is worth of further investigation.