This recent report describes testing the potential therapeutic effects of fruit-derived compounds using a fly model of neurodegenerative disease (a transgenic fly strain expressing human A-beta-42).
Yu Y, Feng XL, Gao H, Xie ZL, Dai Y, Huang XJ, Kurihara H, Ye WC, Zhong Y, Yao XS. Chemical constituents from the fruits of Gardenia jasminoides Ellis. Fitoterapia. 2012 Apr;83(3):563-7. PubMed PMID: 22245087
Models like this in which a disease-associated human gene is expressed in flies are available from the BDSC. Check out BDSC's page on Alzheimers disease fly stocks for example.