[1] His research focuses on the isolation and structural characterization of natural products, and currently investigates the role of biologically active small molecules in mediating symbiotic interactions and disease.
Early on at Iowa State University Clardy established important collaborations with Bill Fenical, John Faulkner and Paul Scheuer,[5] which led to the structure elucidation of numerous marine natural products such as the anticancer agent bryostatin,[6] the insecticidal and antifungal jaspamide, diazonamide A and B,[7] and many others.
Some of his most notable early work focused on the neurotoxins associated with "red tide" – which led to the determination of the three dimensional structures of saxitoxin,[8] of the gonyautoxin group, and the cyclic polyether brevetoxin B.
His longstanding interest in endophytic fungi led to the discovery of the selectively cytotoxic quinone torreyanic acid, the structurally diverse guanacastepenes, the antimycotic agent cryptocin, and many others.
[10] In collaboration with Cameron Currie, Clardy investigated associations between Actinomycetes and insects such as the southern pine beetle, ants and termites that led to the discovery of antifungal agents including dentigerumycin[11][12] and mycangimycin.
[18] In collaboration with Walter Leal, Clardy and colleagues obtained an X-ray crystal structure for the volatile insect pheromone bombykol with its binding partner located on the antennae of female silkworm moths.