Location: Natural Products Utilization Research2013 Annual Report
1a. Objectives (from AD-416):
The long-term objective of this project is to identify and chemically characterize secondary metabolites from natural sources with nutraceutical and/or pesticidal properties as chemical markers for selection of high value crops and/or lead compounds for structure-activity optimization. Over the next 5 years, we will focus on the following objectives: Objective 1. Profile phytochemicals of selected crops (blueberry and rice) to identify species or cultivars with high contents of compounds with beneficial health and/or fungicidal properties to promote development as high value crops. Objective 2. Discover and identify technologies based on secondary metabolites that facilitate the development of commercially viable herbicides, fungicides, insecticides, insect repellants, fish bacterides, and health promoters.
1b. Approach (from AD-416):
Blueberry and rice samples will be extracted with appropriate solvents and the extracts will be analyzed by liquid chromatography-mass spectrometry, as well as by gas chromatography-mass spectrometry. The extracts will also be tested for antioxidant activity using a cell-based antioxidant assay. The chemical profiles of the extracts will be correlated with disease resistance of the samples, as well as antioxidant activity. A bioassay-guided investigative approach will be performed on bioactive extracts in efforts to discover herbicides, fungicides, insecticides, insect repellents, fish bactericides and health promoters. General procedures for isolation of active compounds such as solvent extractions, distillations, column chromatography and thin layer chromatography will be employed. Extracts, fractions and pure compounds will be tested for phytotoxicity, antifungal and insecticidal activity in assays being carried out routinely at NPURU and at collaborator's laboratories. Identification of active compounds will be done using spectroscopic methods (Ultraviolet (UV), Infrared (IR), Mass Spectroscopy (MS), Nuclear Magnetic Resonance (NMR)). Chemical studies modification will be performed on compound(s) that will be identified as "highly active" to improve activity or bioavailability.
3. Progress Report:
Chemical profiling of leaf extracts of two rice cultivars inoculated with a pathogen was completed to determine if certain compounds can be used as chemical markers for fungal resistance. This work is in collaboration with the USDA, ARS, Dale Bumpers National Rice Research Center, Stuttgart, AR. Pterostilbene was shown to inhibit progression of prostate cancer in animals. Pterostilbene inhibited the metastasis protein 1 (MTA1), and reduced tumor size more than resveratrol. This study found: 1) MTA1 is a potential therapeutic target in prostate cancer and 2) pterostilbene is a promising compound for treatment of MTA1-overexpressing advanced prostate cancer. This study provided foundation for a grant awarded to a University of Mississippi Medical Center (UMMC) collaborator to conduct further research on the use of pterostilbene to treat prostate cancer. The biting deterrent effect of a series of fatty acids against the yellow fever mosquito [Aedes (Ae.) aegypti] was investigated, in collaboration with an entomologist at the University of Mississippi. Bioassays on mid-chain length fatty acids showed at 24-h post treatment; lauric acid had a proportion not biting value higher than DEET at low concentrations and a similar value at higher concentrations. Cloth patch assays with human subjects at USDA, ARS, Center for Medical, Agricultural and Veterinary Entomology (CMAVE) showed that the mid-chain length fatty acids were not as effective as DEET against Ae. Aegypti. Phenolic compounds from cashew nut shell liquid were evaluated for activity against Ae. aegypti larvae, in collaboration with CMAVE. Cardol and cardanol derivatives were active. Neither methylation nor hydrogenation of the compounds improved their activities. Large scale synthesis of a mosquito repellent, with duration of action three times longer than DEET, was performed. Toxicity studies were performed by a private company. Collaboration with scientists from China and Brazil yielded: 1) compounds from essential oils of Acorus tatarinowii and Acorus calamus with activity against Colletotrichum (C.) fragariae, Botrytis cinerea and Fusarium oxysporium; 2) compounds from Acorus dahurica that are active against C. fragariae. Phomopsis obscurans and Phomopsis viticola; and 3) identification of compounds from Pileostegia viburnoides with phytotoxic activity. In collaboration with microbiologists from Brazil, bioactive compounds from fungi associated with macroalgae from Antarctica were surveyed. Penicillium spp. recovered from the endemic species Palmaria decipiens and Monostrama hariotii, respectively, yielded extracts with high and selective antifungal and/or trypanocidal activities. Extracts of the phytopathogenic fungi Fomitopsis and Epicoccum species were antifungal and phytotoxic. Acyl derivatives of glucinol were as active against the fish bacteria Flavobacterium columnare and Streptococcus iniae as a drug control.
1. Pterostilbene, a compound found in some foods such as blueberries, inhibits progression of prostate cancer. Prostate cancer is the second leading cause of cancer-related death in men in the U.S.; globally it is the sixth. Treatment options for prostate cancer are still limited. A researcher at the University of Mississippi Medical Center in collaboration with an ARS scientist at the Natural Products Utilization Research Unit, Oxford, MS, showed in animal studies that pterostilbene, a naturally-occurring phenolic compound, reduced tumor growth in animal models of prostate cancer. Pterostilbene inhibited metastasis protein 1, which is involved in processes associated with metastasis. Pterostilbene inhibited the progression of prostate cancer better than resveratrol. Serum levels correlated with tumour size reduction and biochemical parameters measured. This study provides evidence that a dietary component could be used for the treatment of advanced stage prostate cancer. Pterostilbene has been previously identified in blueberries. This study may benefit blueberry farmers, since blueberries are the leading food with this compound. This study may also benefit the male population of the world.
Zhelijazkov, V.D., Cantrell, C.L., Donega, M.A., Astatkie, T. 2013. Bioprospecting for podophyllotoxin in the Big Horn Mountains, Wyoming. Industrial Crops and Products. 43:787-790.