Phenylpropanoids

Phenylpropanoids List

Introduction

Phenylpropanoids are a class of organic compounds containing one or more C6-C3 units (a six-carbon aromatic phenyl group and a three-carbon propylene tail). These compounds are predominantly sourced from plants and synthesized by the amino acid phenylalanine via the shikimate pathway. Apart from serving as natural shields against ultraviolet radiation and herbivores, phenylpropanoids play a pivotal role in facilitating plant-pollinator interactions. They also possess various pharmacological properties, making them useful in pharmaceuticals. Fig. 1 illustrates the molecular structure of eugenol, a phenylpropane compound formally derived from guaiacol.

Fig. 1 Structure of eugenol.

Classification of Phenylpropanoids

There are many kinds of phenylpropanoid compounds, which can be mainly divided into simple phenylpropanoids, coumarins, and lignans. These three phenylpropanoids and their further classification are described below.

• Simple phenylpropanoid

Simple phenylpropanoids represent a prevalent group of aromatic compounds, characterized by their structural derived from phenylpropane. Based on the composition of their C3 side chains, simple phenylpropanoids can be categorized into distinct classes, namely phenylpropenes, phenylpropanols, phenylpropanals, and phenylpropionic acids.

• Phenylpropenes: They encompass a group of volatile compounds, exemplified by eugenol, anethole, α-asarone, and other related constituents.
• Phenylpropanols: Within the realm of phenylpropanols, notable members include coniferyl alcohols and phenylpropanol glycosides.
• Phenylpropanals: They are represented by compounds such as cinnamaldehydes, sinapaldehydes, among others.
• Phenylpropionic acids: They comprise a diverse array of compounds, including p-hydroxycinnamic acids, caffeic acids, ferulic acids, isoferulic acids, and chlorogenic acids.

• Coumarin

Coumarins, characterized by a benzo-α-pyrone skeleton, are derived from phenylpropanoids. According to the different substituents and positions on the benzo-α-pyrone skeleton, coumarin compounds are generally divided into four main subtype classes of compounds: simple coumarins, furanocoumarins, pyranocoumarins, and pyrone-substituted coumarins.

• Simple cumarins: They are basic cumarins containing a benzopyrone ring structure. Examples include coumarin itself and its derivatives like 7-hydroxycoumarin.
• Furanocoumarins: These cumarins contain a furan ring fused to the benzopyrone structure. Examples include psoralen and angelicin, commonly found in plants such as parsley and citrus fruits.
• Pyranocoumarins: These cumarins have a pyran ring fused to the benzopyrone structure. One example is scopoletin, found in several plant species.
• Pyrone-substituted coumarins: They are different from the above-mentioned three types in structure. They contain different chemical radicals fused with the pyran ring of coumarin.

• Lignan

Lignans represent a class of intricate polymers derived from phenylpropanoids, exhibiting a widespread presence in various plant parts such as roots, rhizomes, leaves, flowers, fruits, seeds, and xylems. These compounds typically arise from the polymerization of two or more phenylpropanoid units and are predominantly found in a free state, with some forming glycosides in conjunction with sugars. They can be categorized based on the following two methods.

• According to their structure, lignans can be classified into lignans, neolignans, norlignans, hybrid lignans, and oligomeric lignans.
• According to the way in which oxygen is incorporated into the skeleton and the cyclization pattern, lignans can be classified into eight subgroups: furofurans, furans, dibenzylbutane, dibenzylbutyrolactone, ariltetralin, arylnaphthalene, dibenzylcyclooctadiene, and dibenzylbutyrolactol ^[1].

Alfa Chemistry offers an extensive array of phenylpropanoids and their derivatives, encompassing simple phenylpropanoids, coumarins, lignans, and more. For a comprehensive view of our product catalog, kindly access the link provided at the top of this page. Alternatively, utilize the search functionality on our website to locate specific products of interest. If you do not find the product you need, please do not hesitate to contact us. We can also provide customized synthesis of phenylpropanoids according to customer requirements.

Reference:

1. Toshiaki, U. Diversity in lignan biosynthesis. Phytochemistry Reviews. 2003, 2: 371–390