The 2009 ASHS Annual Conference

Medicinal and aromatic plants have a long history of use in traditional medicine by many cultures, especially Asia.  Natural product-derived agrochemicals and pharmaceuticals are used Worldwide and are the source of 78% of anti-infectives used in plant protection, veterinarian and human disease applications because most of these compounds evolved from microbial warfare.  Nature has also produced a wide array of anti-proliferative agents and 74% of today’s anticancer compounds have their origin in secondary plant metabolism.  We present our most recent studies on fungicidal, insecticidal, and mosquito deterrent activity conducted by the USDA, ARS, Natural Products Utilization Research Unit in a wide area of natural product agrochemical discovery.  
Essential oils represent an unusually complex class of natural products which are isolated from aromatic plants.  While many volatile oils have been evaluated for activity again human pathogens very few have been evaluated as plant protectants against agriculturally important plant pathogens and insects.  As part of a program to discover natural product-based fungicides, sensitive detection systems were developed for evaluation of antifungal agents as agrochemical plant protectants.  Our lab has established improved bio-monitoring and separation techniques of antifungal compounds using planar formats.  Plant extracts are an extraordinary complex matrix of lipophilic, non-lipophilic, and nuisance chemistry and  Overpressured-layer chromatography (OPLC) was effectively used to quickly separate co-migrating compounds and perform chemical finger printing.  Also, a novel 24-well plate leaf bioassay was developed to test new fungicides that are available in small amounts and are lipophilic in nature.
The natural compound, sampangine, was first patented by the university in 1990 by the University of Mississippi (UM) as a potential treatment for human fungal-infections and was later patented by ARS/UM in 2005 as a novel agrochemical fungicide.  Sampangine is derived from a natural product first isolated from the bark of Cleistopholis patens (Anonaceae).  Sampangine can be used to treat fungi such as:  Botrytis cinera, Colletotrichum fragaraie, Colletotrichum acutatum, Colletotrichum gloesporiodes. The antifungal cyclopentenedione coruscanone A, isolated from the Peruvian plant, Piper coruscans was patented in 2006 and showed promising antifungal activity against B. cinerea, C. fragariae, C. acutatum, C. gleosporioides, F. oxysporium, Phomopsis obscurans, and P. viticola. Data suggests that these compounds may be useful as a broad spectrum agricultural fungicides.  We will also present detailed results on other medicinal and aromatic plants.