Infusing the Undergraduate Curriculum with Medicinal Chemistry Techniques Using Real-World Examples Involving Bioassay-Directed Synthesis of Chalcone-based Citrus Fruit Bioregulators

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 18 (2013) pp 295-301
DOI 10.1007/s00897132510

Infusing the Undergraduate Curriculum with Medicinal Chemistry Techniques Using Real-World Examples Involving Bioassay-Directed Synthesis of Chalcone-based Citrus Fruit Bioregulators

Joseph K. Rugutt*^,†, Travis L. Pohl^†, Benton G. Grills^†, Taewan Park^†, Chulapol Thanomsing^†, Christine Chemutai Bii^‡, Kipngeno J. Rugutt^§, Joel Koech^**, Britteny Duru^††, Leyla Gil^††, and Grecia Leslie^††

†Math and Science Division, Missouri State University-West Plains, 128 Garfield, West Plains, MO 65775, JRugutt@MissouriState.edu; ‡Research Scientist Medical Mycology, Center for Microbiology Research, Kenya Medical Research Institute, KNH 00202 Nairobi, Kenya;§Illinois State University, Department of Educational Administration and Foundations, College of Education, DeGarmo 331, Campus Box 5900, Normal, IL 61790-5900; **School of Science & Technology, Department of Biological Sciences, University of Kabianga, Main Campus,P.O. Box 2030,20200, Kericho City, Kenya; ††Department of Chemistry, Columbus State University, 4225 University Ave., Columbus, GA 31907
Received April 8, 2013. Accepted May 18, 2013.

Published: 28 October 2013

Abstract. 1-phenyl-3-(p-diethylaminoethoxyphenyl)-2-propen-1-one, a chalcone-based bioregulator, was synthesized through a two-step process involving Claisen-Schmidt condensation of benzaldehyde and acetophenone followed by nucleophilic substitution with diethylaminoethyl chloride hydrochloride. The bioregulator induced significant production of lycopene in citrus fruits (i.e., oranges and lemons). The intermediate chalcone phenoxide anion as well as chalcone, ergosterol, and cholesterol were less effective compared to the bioregulator. Lycopene has been the focus of many studies because of its anti-prostate cancer and anti-oxidant properties. Our bioassays were straightforward. Citrus fruits were coated with bioregulators and placed near a window to allow carotogenesis to occur within seven days. A thin layer of citrus fruit peel was removed using a grater then extracted with n-hexane. The amount of lycopene in n-hexane was determined using UV absorption spectroscopy. Chalcone-based bioregulators were chosen for the model medicinal organic chemistry experiment because chalcones are real chemical estates that easily lend themselves to robust multidisciplinary research opportunities such as integrating the world’s best synthetic methods developed by Nobel Laureates (e.g., Diels-Alder, Smalley, and Corey), nanomaterials, and green chemistry into undergraduate curriculum. The proposed experiments were carefully designed so that they match the skill levels of students at two- and four-year colleges. Our ongoing US-Africa medicinal project focuses on hypothesis-driven guided inquiry synthesis of novel chalcone-based citrus bioregulators. The goal is to optimize the activity of enantiomers of bioregulators. Since the individual enantiomers may vary in biological activities, their bioregulatory profile will provide important information needed to understand possible physiological effects on citrus fruits.

Key Words: Laboratories and Demonstrations; organic chemistry; Aldol condensation; chalcones; bioregulators

(*) Corresponding author. (E-mail: JRugutt@MissouriState.edu )

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