Glucosinolates in Sisymbrium officinale (L.) Scop.: Comparative Analysis in Cultivated and Wild Plants and in Vitro Assays with T2Rs Bitter Taste Receptors

Abstract

Sisymbrium officinale (L.) Scop., commonly known as "hedge mustard" or "the singer's plant" is a wild plant common in Eurasian regions. Its cultivation is mainly dedicated to herboristic applications and it has only recently been introduced into Italy. The active botanicals in S. officinale are glucosinolates, generally estimated by using UV or high-performance liquid chromatography (HPLC). Using both techniques, we measured the total glucosinolates from S. officinale in different parts of the plant as roots, leaves, seeds, and flowers. A comparison was made for cultivated and wild samples, and for samples obtained with different pre-treatment and fresh, frozen, and dried storage conditions. Cultivated and wild plants have a comparable amount of total glucosinolates, while drying procedures can reduce the final glucosinolates content. The content in glucoputranjivin, which is the chemical marker for glucosinolates in S. officinale, has been determined using HPLC and a pure reference standard. Glucoputranjivin and two isothiocyanates from S. officinale have been submitted to in vitro assays with the platform of bitter taste receptors of the T2Rs family. The results show that glucoputranjivin is a selective agonist of receptor T2R16.

Isothiocyanates and Glucosinolates from Sisymbrium officinale (L.) Scop. (“the Singers’ Plant”): Isolation and in Vitro Assays on the Somatosensory and Pain Receptor TRPA1 Channel

“…Hydrolysis mainly leads to IPITC (compound 2 ), followed by 2-BITC (compound 4 ). The percentage of the two compounds varies in different samples, with compound 2 always being the main component in leaves, seeds and flowers; compound 4 is present in variable amounts, reaching 24% of total volatiles in a sample of fresh flowers [ 28 ]. The compound 2-BITC is the hydrolysis product of glucochoclearin 3 ; it is abundant in plants of the genus Cochlearia and has been previously found also in SO [ 5 ].…”

Chemoinformatics View on Bitter Taste Receptor Agonists in Food

“…The similarity of TAS2R16 agonists was highlighted also with the scaffolds analysis, and it is well renowned because TAS2R16 is specialized in the recognition of “bitter sugars”, 57 as glucopyranosides 38 and glucosinolates. 32 Similarly, TAS2R5 shows specificity toward polyphenols: it is activated only by compounds belonging to the phenylpropanoids and polyketides superclass. This indication could be relevant for TAS2R5-targeted nutritional studies in the future because polyphenols are biomolecules with a well-established positive impact on nutrition and health.…”

“…In vitro assays can be run on milligram scale samples and do not require preliminary toxicity tests . Some of the recently identified TAS2R agonists have not even been submitted to sensory analysis. , Functional assays led to a new array of data connected to bitter compounds, and for a better understanding of the molecular recognition of bitter compounds, supporting the combinatorial coding of the bitter taste percept. Some bitter receptors are broadly tuned and respond to a wide range of structurally diverse bitter compounds, whereas others are very selective for one or a small number of compounds .…”

Sisymbrium Officinale (the Singers’ Plant) as an Ingredient: Analysis of Somatosensory Active Volatile Isothiocyanates in Model Food and Drinks

“…Samples of honey showed a low ITCs release; only sample S5, containing seeds and submitted to grinding before analysis, has an ITCs content much higher than the others, confirming that ITCs are well preserved in the plant material and their release is favoured by the activation of enzymatic hydrolysis. Since the precursor glucosinolates are most abundant in flowers than in seeds [ 13 ], the lower content of ITCs in honey with flowers can be related to a loss due to various enzymatic processes, which can involve flowers more than seeds. In fact, flowers’ tissues have about 90% water, whereas seeds are mainly constituted by oil and are therefore protected by enzymatic hydrolysis until grinding occurs.…”

“…Compounds 1-8 are shown in Figure 1. A comparative analysis of GLSs in wild and cultivated SO has been recently published [13]. An extensive analysis of volatile compounds obtained by the hydrodistillation by GCMS was described and showed the presence of at least 42 different volatile compounds in SO, including several ITCs.…”