Philip H. Evans

Thallphytic Alleopathy: Isolation and Identification of Laetisaric Acid

Laetisaria arvalis, a soil-dwelling basidiomycete fungus, secretes an allelopathic agent that induces rapid hyphal lysis in several phytopathogenic fungi. The active compound was isolated from chloroform:methanol extracts of L. arvalis mycelia and characterized as a previously unknown hydroxy fatty acid, (Z,Z-9,12-8-hydroxyoctadecadienoic acid.

Activity of Turkish medicinal plants against mosquitoes Aedes aegypti and Anopheles gambiae

Organosoluble extracts from 55 Turkish medicinal plants were tested under standardised conditions for biological activity against third-instar larvae of mosquitoes Aedes aegypti and Anopheles gambiae. Eight extracts demonstrated significant larvicidal activity, with An. gambiae being more susceptible than Ae. aegypti in all cases. The possibility of using indigenous plants for mosquito control is discussed.RésuméDes extraits organosolubles provenant de 55 plantes médecinales de Turquie ont été testés sous conditions standardisées pour leur activité biologique sur des larves du 3è stade d’Aedes aegypti et Anopheles gambiae. Huit extraits ont démontré une activité larvicide significative, avec An. gambiae étant plus susceptible qu’Ae. aegypti dans tous les cas. Les possibilités d’utilisation des plants indigènes pour la lutte contre moustiques a été discutée.

Plumbagin from Diospyros olen

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) (CAS Reg. No. 481-42-5) was isolated from the bark of Diospyros olen (Ebenaceae) via an antibiotic guided biological assay using the bacterium Pseudomonas solanacearum. D. olen bark, collected in New Caledonia, was extracted with dichloromethane and components separated by flash chromatography on silica.[...]

Enteric and Plant Derived Deterrents in Regurgitate of American Bird Grasshopper, Schistocerca americana

Regurgitates of the grasshopper Schistocerca americana were deterrent to Crematogaster ants. Regurgitates obtained from insects fed upon wheat seedlings were more strongly deterrent than those obtained from insects fed on romaine lettuce leaves. After extraction of the regurgitates with ethyl acetate, deterrence could be demonstrated in both the organic and aqueous phases. Wheat seedlings, lettuce, and feces from wheat- or lettuce-fed insects yielded extracts with lower deterrency. Our results suggest that deterrents in the organic phase of the regurgitate are primarily due to the presence of plant natural products, whereas the deterrency of the aqueous phase is probably due to digestive enzymes from enteric components, probably digestive enzymes.