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

Abstract

Sisymbrium officinale (L.) Scop. is a wild common plant of the Brassicaceae family. It is known as “the singers’ plant” for its traditional use in treating aphonia and vocal disability. Despite its wide use in herbal preparations, the molecular mechanism of action of S. officinale extracts is not known. The plant is rich in glucosinolates and isothiocyanates, which are supposed to be its active compounds. Some members of this family, in particular allylisothiocyanate, are strong agonists of the transient receptor potential ankyrin 1 (TRPA1) channel, which is involved in the somatosensory perception of pungency as well as in the nociception pathway of inflammatory pain. This study aims to isolate the glucosinolates and isothiocianates from fresh S. officinale to identify the major components and test their activity in in vitro assays with a cloned TRPA1 channel. Samples of cultivated S. officinale have been extracted and the active compounds isolated by column chromatography, HPLC and PTLC. The main components glucoputranjivin, isopropylisothiocyanate and 2-buthylisothiocianate have been tested on TRPA1. The glucosinolates glucoputranjivin and sinigrin turned out to be inactive, while isopropylisothiocyanate and 2-buthylisothiocyanate are potent agonists of TRPA1, with an EC50 in the range of the high potency natural agonists identified so far for this somatosensory channel.

Moringin, A Stable Isothiocyanate from Moringa oleifera, Activates the Somatosensory and Pain Receptor TRPA1 Channel In Vitro

“…Many of them, included Moringa oleifera, are important crops for human and animal diets and are also commonly used as traditional remedies. Allylisothiocyanate (mustard oil) is the reference agonist for TRPA1; other isothiocyanates as benzyl-, phenylethyl-, isopropyl-, and methyl-isothiocyanates have been proved to activate TRPA1 in vitro [43,44]. The role of TRPA1 channel in pain has been extensively reviewed [45,46].…”

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

“…In a previous work we demonstrated that isopropyl isothiocyanate 4 is an effective agonist on the somatosensory ion channel TRPA1 in vitro, [15], whereas glucoputranjivin 3 is inactive on this ion channel. In the present work, we identified glucoputranjivin 3 as a selective agonist of T2R16 receptor in vitro.…”

“…Glucoputranjivin 3 is the main GLS in S. officinale; its quantitative determination in all the parts of the plant has not been described previously. We performed this analysis by RP-HPLC using an authentic sample of this compound, previously obtained in our laboratory [15], as the reference standard to build a calibration curve.…”

“…Sinigrin 1 is reported to activate receptors T2R38 and T2R16 [13] of the bitter family, whereas allyl isothiocyanate 2 is the reference agonist for TRPA1 ion channel, a sensor for pungency [14]. It has been recently reported [15] that the two main volatile ITCs from SO, isopropyl isothiocyanate 4 and 2-buthylisothiocyanate 6, are also strong agonist in vitro of the TRPA1 somatosensory ion channel, which is involved in the somatosensory perception as well as in the nociception pathway of inflammatory pain [14,16,17].…”

Effect of Fertilization on Yield and Quality of Sisymbrium officinale (L.) Scop. Grown as Leafy Vegetable Crop

“…Plants in the Brassicaceae family are rich in TRPA1 active compounds. Borgonovo et al found that in vitro essay of isothiocyanate (ITC), isopropylisothiocyante (IPITC) and 2-buthylisothiocyanate (2-BITC) are selective and, in some cases, potent antagonists of TRPA1 channels [34].…”