toothache plant

Acmella oleracea is a plant in the daisy family, also called jambu in Portuguese and toothache plant in English. The English name contains the word for tooth pain, but the name itself is not a record that the plant was shown to work. According to a review, its raw leaves have been used as a salad flavoring in the United States, as a cooked vegetable added to soups and meat dishes in India, and as a major leafy vegetable in Indigenous Brazilian cuisine. In Java, Indonesia, young shoots and leaves are served as raw (a raw-vegetable preparation) with sambal, while in Thailand both leaves and flower heads are used in various curries. In Japan, the flowers are prized as an edible spice; the flower buds are commercially known as Buzz Buttons, Szechuan Buttons, or Electric Buttons and are used in gastronomy to counter the heat of chili peppers.

The plant's main group of constituents is described as alkylamides (a group of nitrogen-containing, lipid-like compounds), with spilanthol occupying a central place in the literature. A plant information page of Mahidol University in Thailand also names spilanthol as a constituent for the Thai name assigned to this plant. Spilanthol and structurally related fatty acid amides are described as causing pungency, tingling, numbing, mouthwatering and cooling, that is, touch and temperature sensations of the tongue and mouth (somatosensory sensations). In an experiment on isolated mouse taste bud cells, many cells responded more strongly to table salt when spilanthol was added. Content is described as varying by plant organ, place of origin, and extraction method; individual measurement records are needed to demonstrate those differences. The descriptions of mouth sensations come from a paper's background summary of earlier studies, not from measurements in people by this page's sources. The salt-response experiment was in mouse cells, and results in people are described as preliminary and unpublished.

However, it has been pointed out that more than a few Thai ethnobotanical and phytochemical records labeled Acmella oleracea or Spilanthes acmella may actually refer to Acmella paniculata, the most widely distributed native species. A study that reclassified 6 Thai Acmella species states that those two names account for about 80% of all Thai use records and that many of them could refer to A. paniculata. The correspondence between a local name and the scientific name Acmella oleracea must also be read as a folk species name that could encompass several closely related species.