Undergraduate Student Oral and Poster Presentations at Professional Meetings (with Venugopal Mukku)
Lydia Hegge, Venugopal J. Mukku, Psuedoguaianolides from Helenium flexuosum seeds. National Conference on Undergraduate Research, University of North Carolina Asheville, Asheville, NC, April 7-9, 2016. Abstract
You Bin Lee, Sierra Trost, Brian Dingmann and Venugopal Mukku. Using alamar blue cell viability assay to screen for putative antimicrobial products. National Conference on Undergraduate Research, University of North Carolina Asheville, Asheville, NC, April 7-9, 2016. Abstract. Abstract
Michael Laurich, Emmett LaCoursiere, Bryce Tradewell, Venugopal J. Mukku, Timothy J. Dudley, E. Peterson, W. J. Boyko, Nicholas A. Piro, William S. Kassel, Jared J. Paul. Synthesis and characterization of neutral and ionic forms of ortho- and para-hydroxyphenyl benzimidazoles. 50th Midwest Regional Meeting of American Chemical Society, St. Joseph, MO, Oct 21-24, 2015. (poster)
Brooke Vatthauer, Rochelle Herzog, Jason Brantner and Venugopal J. Mukku. HPLC fingerprinting of biologically active extracts from Streptomyces. National Conference on Undergraduate Research, Eastern Washington University, Cheney, WA, April 16-18, 2015. (oral) Abstract
Emmett LaCoursiere, Michael Laurich, Venugopal J. Mukku, Timothy J. Dudley, David D. Mall, W.J. Boyko, William G. Dougherty, William S. Kassel, Jared J. Paul. Theoretical and experimental investigations of ortho and para-hydroxyphenyl benzimidazoles. 49th Midwest Regional Meeting of American Chemical Society, Columbia, MO, Nov 12-15, 2014. (poster)
Gyuongyoun Baek, and Venugopal J. Mukku. Isolation and characterization of bioactive pseudoguaianolides from Helenium flexuosum. National Conference on Undergraduate Research, University of Kentucky, Lexington, KY, April 3-5, 2014. Abstract
Constantin Adelakoun, Danielle Wavra, Jake Heggem, Jason Brantner, Venugopal J. Mukku, Streptomyces ‘beets’ Aphanomyces. National Conference on Undergraduate Research, LaCrosse, WI, April 11-13, 2013. (Oral)
Shawn Friedland, Brian J. Dingmann, Venugopal J. Mukku. Flavonoids from native Minnesotan plants. Undergraduate Research in Molecular Sciences, Moorhead, MN, October 28-29, 2011. (poster)
Shawn Friedland, Heather Donati Lewis, Brian J. Dingmann, Venugopal J. Mukku. Antibacterial activity of selected Minnesota seeds. American Society of Pharmacognosy Annual Meeting, San Diego, CA, July 30-August 3, 2011. (poster) Abstract
Heather Donati Lewis, Brian J. Dingmann, Venugopal J. Mukku. Common spices and uncommon properties. National Conference on Undergraduate Research, Missoula, MT, April 15-17, 2010. (Oral) Abstract
Title: Psuedoguaianolides from Helenium flexuosum seeds
Abstract: Natural products continue to play an important role in drug discovery and development. The recent award of Nobel Prize in physiology and medicine to scientists who discovered artemisinin (antimalarial) and avermectins corroborates the importance of both random screening and screening based on ethno-pharmacological resources. Other examples of natural product derived compounds used in modern medicine include taxol and simvastatin derived from Taxus brevefolia and Aspergillus terreus respectively. The focus of our research is to discover new chemical entities with antimicrobial properties to combat pathogens resistant to multiple classes of existing antimicrobials. In our ongoing screening of Native American medicinal plants for antimicrobial properties we have found that Helenium flexuosum seed extracts exhibited moderate activity against Staphylococcus aureus. A series of pseudoguainolide esters were isolated using column chromatography over silica gel followed by RP HPLC. Pseudoguainolides are a type of hydroazulenic sesquiterpene lactones having an angular ß methyl group at C-5 instead of at C-4 as in normal guainolides. Structures were established using a combination of 2D NMR and mass spectral data. Details of the structural elucidation of these compound(s) will be presented. Pseudoguainolides are garnering increased interest as lead molecules that possess anticancer, antimalarial, antibacterial, antifungal properties.
Title: Using alamar blue cell viability assay to screen for putative antimicrobial products
Abstract: The number of pathogens resistant to antibiotics in hospitals and communities is on the rise. The costs associated with the treatment and work loss run into billions of dollars annually. Our research is focused on discovering new compounds with antimicrobial properties. With that goal in mind we have screened 30 crude plant extracts obtained from a phytochemical company. We screened these extracts on a mini panel of BSL 1 pathogens (Candida albicans, Aspergillus niger, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli) in 96 well plates. The Alamarblue® cell viability assay was used to screen against the pathogens. Viability was determined by reduction of Alamarblue®, which changes the color from blue to pink/red. Crude extracts with minimum inhibitory concentration (MIC) at or < 256 µg/ml were prioritized for further study. Four extracts showed activity against both Candida albicans and Aspergillus niger and three extracts demonstrated activity against Aspergillus niger only. The Alamarblue® viability assay is a cost-effective, quick and easy method to test for antimicrobial activity. The method can be easily utilized by any researcher interested in drug discovery and new antimicrobial products.
Title: HPLC fingerprinting of biologically active extracts from Streptomyces
Abstract: Aphanomyces cochlioides causes damping-off and root rot in sugar beet under warm and wet soil conditions which results in decreased yields. Treating the soils with lime reduced the problem and led to concomitant increase in the number of Streptomyces strains in the soil. It was hypothesized that these Streptomyces strains are involved in the observed effect. Thirty six strains isolated from the soil were grown on GYEA plates and examined for activity on Candida albicans and Bacillus subtilis. One strain (NWROC -11B) was prioritized and was grown on a shaker for a week. The media was vacuum filtered and the organic compounds were extracted using ethyl acetate. The ethyl acetate extract was subjected to reversed phase HPLC in order to finger print the extract and compare it with subsequent cultures and fermentations. Various fractions from the HPLC are now being tested in order to localize the activity. The fractions will also be tested for activity against A. cochlioides.
Title: Isolation and characterization of bioactive pseudoguaianolides from Helenium flexuosum
Abstract: Natural products in general played a predominant role in drug discovery and development. Almost 70% of antibacterial and anticancer drugs are either natural products or are derived from natural products. However, the rate of discovery of new chemical entities with antibacterial activity is lagging behind the development of drug resistant pathogens. Particularly important at this juncture is the discovery of new pharmacophores. With a view to explore the chemical diversity of Native American plants and their antibacterial potential we started a systematic screening of twenty two plant seeds. Disc diffusion assay was used to evaluate the antibacterial activity. Initial results led to the prioritization of two plants: Helenium flexuosum and H. autumnale (Family: Asteraceae). This presentation will focus on the chemical examination of H. flexuosum. H. flexuosum seeds were powdered and extracted repeatedly with methanol and the combined methanol was evaporated on a rotavapor. The residue from the methanol extract was subjected to Kupchan partition and the antibacterial activity was localized in the dichloromethane fraction. Repeated chromatography of the dichloromethane fraction on normal and reverse phase columns using a Biotage flash chromatography system resulted in a number of fractions. Thin Layer Chromatography and 1H NMR analysis of these fractions suggested the presence of closely related compounds. Further chromatography over silica gel using hexane – acetone and toluene – acetone afforded a pure compound, isohelenol, which was previously reported from Helenium microcephalum and was reported to have in vivo activity against mouse P388 lymphocytic leukemia. However, this is the first report of this compound from H. flexuosum. Isohelenol belongs to the pseudoguaianolide class of sesquiterpene lactones. The significance of this work lies in the fact that this class of compounds have gained considerable interest for treating human diseases such as inflammation, headache and infections.
Title: Antimicrobial activity of selected Native American seeds
Abstract: Antibacterial activity profiles for 22 seed extracts against five pathogens were evaluated using a disc diffusion assay. Helenium flexuosum, H. autumnale, Epilobium angustifloium, E. coloratum and E. glandulosum showed activity against S. aureus, E. aerogenes and P. aeruginosa. The two Helenium species exhibited moderate activity. Bioassay guided chemical examination of H. autumnale afforded the flavonoids apigenin and luteolin of which luteolin showed weak activity against S. aureus.
Title: Common spices and uncommon properties
Abstract: Potent; invoking feelings of nostalgia in some while compelling others to wrinkle their nose, spices play a powerfully integral role in our everyday lives. Unbeknownst to most, these common cabinet dwellers hide secrets beyond belief. For example, a few well known plants and herbs, better known for their flavor, have been reported to have antimicrobial and even antibiotic properties. A case in point is Thevetia peruviana or yellow oleander that is known for its antimicrobial activity. We have now tested 35 diverse plants including the yellow oleander for anti-fungal characteristics. These plants originate from multiple continents and represent a variety of botanical families. The experiment utilized an enzyme assay to test for chitinase inhibition, which is an enzyme used by insects and fungi to construct exoskeleton structures or cell walls. The targeting of chitinase prevents any treatments from impacting host cells or beneficial crops but still acting as an effective treatment for unwanted organisms. The method involves the incubation of the crude methanol plant extract with chitinase and its substrate, chitin azure. The level of inhibition is found by measuring the absorbance of the resulting reaction and comparing it to a control. Out of the 35 plant extracts, four (11%) demonstrated chitinase inhibition at levels as low as 250 micrograms of crude extract per milliliter. Among the active extracts are Thevetia peruviana and Euphorbia hirta (asthma weed) which was previously thought to be a natural antihistamine and antiamoebic. Further studies are under way to determine the minimum inhibitor concentration (MIC). The high hit rate underlines the importance of plants in drug discovery and encourages the pursuit of pharmacological research.