Introducing Organic Chemistry Students to Natural Product Isolation Using Steam Distillation and Liquid Phase Extraction of Thymol, Camphor, and Citral, Monoterpenes Sharing a Unified Biosynthetic Precursor

Abstract

Plants have provided and continue to provide the inspiration and foundation for modern medicines. Natural product isolation is a key component of the process of drug discovery from plants. The purpose of this experiment is to introduce first semester undergraduate organic chemistry students, who have relatively few lab techniques at their disposal, to the process of natural product isolation. In one, 3 h lab period, students use steam-distillation and liquid-phase extraction to isolate a single medicinally relevant molecule from one of three plants. The identity of the molecule can be demonstrated using infrared spectroscopy and thin-layer chromatography. Students choose to isolate thymol from thyme (Thymus vulgaris), citral from lemongrass (Cymbopogen), or camphor from sagebrush (Artemisia tridentata)three commercially available plants with a long history of use. Each isolated molecule has a common biosynthetic origin in the plant, and this is discussed to introduce the relationship between organic chemistry and biochemistry.

Isolation of biologically active compounds from mangrove sediments

“…Similar to work presented here, extraction procedures involved the utilization of various organic solvents [28][29][30]. The range of chromatographic techniques varied from simple paper chromatography [31] and TLC [30,[32][33][34], with the latter noting, "the students recognize that TLC does not have the resolving power necessary to separate the extracted compounds and are guided towards a more powerful alternative, HPLC" [35]. HPLC is widely used in undergraduate teaching environments [35][36][37][38], so the utilization of HPLC in this paper is an obvious choice given the complexity of the extract.…”

Isolation of Natural Steroids from Corn Silk Using Recycling Preparative HPLC: A Natural Products Discovery Assignment for the Undergraduate Chemistry Student

“…The assignment is divided into three parts: (1) the extraction of plants of interest, (2) the isolation and identification of natural products in the plant, and (3) the evaluation of the cytotoxicity of the isolated compounds. These procedures are commonly used in many research laboratories around the world. , In addition, there are several experiments in the chemical education literature that, applied to several undergraduate isolation experiments, demonstrate the separation techniques − and spectroscopic characterization of natural products. − The need for the isolation and purification of natural products has led to continuous improvements and advancements in separation techniques. The present study describes the efficient isolation and separation of natural products from corn silk by Recycling Preparative High-Performance Liquid Chromatography (HPLC).…”

Multiple Solid–Liquid Extraction: Determination of Extraction Yield through UV–Vis Spectroscopy

“…The extraction of compounds from solid matrices is considerably significant in the chemical industry and provides lots of input also in teaching. − In particular, the extraction of natural compounds greatly stimulates the interest of students, and therefore, teachers are very interested in the conception of laboratory methods on this topic. ,, The fact that many natural compounds absorb intensely in the visible region of the electromagnetic spectrum makes experiments intuitive and easy to carry out. , Many papers published in this Journal deal with extractions of natural solid matrices with the purpose of characterizing − or separating/quantifying − the extracted compounds.…”