Antimicrobial compounds isolated from Tropaeolum tuberosum.

Activity-guided fractionations of black tubers of Tropaeolum tuberosum led to the isolation of 3-[3-(3-pyridinyl)-1,2,4-oxadiazol-5-yl] benzonitrile (1) and [3,5-Bis (1,1-dimethylethyl)-4-hydroxyphenyl] ethenylidene] bis-phosphonic acid tetraethyl ester (2). Compounds 1 and 2 showed an antibacterial effect against almost all the strains assayed, especially compound 2, showing the same inhibition potential for Enterococcus faecalis and Salmonella enteritidis as the ampicillin (MIC = 1.5 µM) and a better potential than chloramphenicol which has a MIC of 3.5 µM. In addition, compounds 1 and 2 showed a relevant antifungal inhibition against Candida tropicalis with MICs of 100 µM and 50 µM, and against Saccharomyces kudriavzevii with MICs of 25 µM and 1.5 µM. This is in comparison to fluconazole which had MICs of 150 µM (against Candida tropicalis) and 3.5 µM (against Saccharomyces kudriavzevii). This is the first time that compounds 1 and 2 are reported as showing antimicrobial activities.

Identification of TRPV1 Ion Channels Agonists of Tropaeolum tuberosum in Human Skin Keratinocytes.

Tropaeolum tuberosum, commonly known as Mashua, is an herbal remedy used in traditional Andean medicine for the relief of kidney and bladder pain, as well as contusions. This study aimed to evaluate the fractions and isolated compounds from T. tuberosum with analgesic activity mediated by the transient receptor potential vanilloid-1 receptor. A bioguided phytochemical analysis based on NMR/MS was performed to identify the compounds of the n-heptane fractions from samples of purple tubers of T. tuberosum. The transient receptor potential vanilloid-1 agonist and antagonist activity were assessed through the measurement of intracellular Ca2+ in HEK001 cells. The chemical structure determination led to the identification of two alkamides: N-(2-hydroxyethyl)-7Z,10Z,13Z,16Z-docosatetraenamide (1: ) and N-oleoyldopamine (2: ). Both compounds induced increased intracellular calcium flow with IC50 values of 3.2 nM and 7.9 nM, respectively, thus activating the transient receptor potential vanilloid-1 receptor. Our research is the first report to show that these two compounds isolated from T. tuberosum can act as agonists of the transient receptor potential vanilloid-1 receptor, providing scientific evidence for the traditional use of this species in pain relief.