Acmella oleracea


Acmella oleracea is a species of flowering herb in the family Asteraceae. Common names include toothache plant, paracress, Sichuan buttons, buzz buttons, tingflowers and electric daisy. Its native distribution is unclear, but it is likely derived from a Brazilian Acmella species. It is grown as an ornamental and attracts fireflies when in bloom. It is used as a medicinal remedy in various parts of the world. A small, erect plant, it grows quickly and bears gold and red inflorescences. It is frost-sensitive but perennial in warmer climates.
Its specific epithet oleracea means "vegetable/herbal" in Latin and is a form of .

Culinary uses

For culinary purposes, small amounts of shredded fresh leaves are said to add a unique flavour to salads. Cooked leaves lose their strong flavour and may be used as leafy greens. Both fresh and cooked leaves are used in dishes such as stews in northern Brazil, especially in the state of Pará. They are combined with chilis and garlic to add flavor and vitamins to other foods.
The flower bud has a grassy taste followed by a strong tingling or numbing sensation and often excessive salivation, with a cooling sensation in the throat. The buds are known as "buzz buttons", "Sichuan buttons", "sansho buttons", and "electric buttons". In India, they are used as flavoring in chewing tobacco.
A concentrated extract of the plant, sometimes called jambu oil or jambu extract, is used as a flavoring agent in foods, chewing gum, and chewing tobacco. The oil is traditionally extracted from all part of the plant. EFSA and JECFA reviewed a feeding study in rats conducted by Moore et al. and both authorities recognized that the no adverse effect level for spilanthol was 572 mg/kg b.w./day, yielding a safe dose of spilanthol of 1.9 mg/kg b.w./day, or 133.5 mg/70-kg-male/day, 111 mg/58-kg-female/day, or 38 mg/20-kg-child/day.
Jambu extract as a flavoring agent is described as having a citrus, herbal, tropical or musty odor, and its taste can be described as pungent, cooling, tingling, numbing, or effervescent. Thus, as described, the flavor use of jambu extract includes the ability induce a mouth-watering sensation and the ability to promote the production of saliva. Spilanthol, the major constituent of jambu extract, is responsible for the perception of a mouth-watering flavor sensation, as well as the ability to promote salivation as a sialogogue, perhaps through its astringent action or its pungent taste.
Jambu extract can also be used in cosmetics and shampoos.

Cultivation

This plant prefers well-drained, black soil. If starting outdoors, the seeds should not be exposed to cold weather, so start after last frost. Seeds need direct sunlight to germinate, so should not be buried.

Medicinal uses

A decoction or infusion of the leaves and flowers is a traditional remedy for stammering, toothache, and stomatitis.
An extract of the plant has been tested against various yeasts and bacteria and was essentially inactive. It has been shown to have a strong diuretic action in rats.
As a bush plant used for treating toothache, the analgesic effect of the Spilanthes plant has been attributed to the presence of constituents containing an N-isobutylamide moiety, such as spilanthol, a substance that has been found to be an effective sialogogue, an agent that promotes salivation. Spilanthol is absorbed trans-dermally and through the buccal mucosa. Spilanthol may activate TRPA1, a specific transient receptor potential ion channel in the oral cavity. In addition to capsaicin, allyl isothiocyanate, and cinnamaldehyde, spilanthol is also reported to affect the catecholamine nerve pathways present in the oral cavity that promote the production of saliva, which is responsible for its ability to induce a mouth-watering sensation when used as a flavor.
Since 2000, there are several medicinal activities reported for Acmella oleracea:
Pharmacological activitySpeciesPart usedType of extractModels used
Antimalarial, larvicidalS. acmella Murr.FlowersEthanolAnopheles, Aedes, Culex larvae
Antinociception, antihyperalgesicS. acmellaFlowersCWEFormalin test of nociception and carrageenan-induced thermal hyperalgesia in rats
Antinociception, antihyperalgesicAcmella uliginosa, CassFlowersMethanolChemicals and thermal models of nociception in mice
ImmunomodulatoryS. acmella Murr.LeavesEthanolMacrophage function in mice
ImmunomodulatoryS. acmellaLeavesEthanolNeutrophil adhesion test in rat
AntiviralS. americanaFlowersNANA
InsecticidalS. calvaLeaves and flowersPetroleum ether, ethyl acetate and methanolHelopeltis theivora
Antimalarial, larvicidalS. acmella, S. calva, S. paniculataFlowersHexaneA. stephensi, A. culicifacies, C. quinquefasciatus larvae
AntioxidantS. acmellaLeaves, stemsMethanolDPPH, SOD assay
AntihepatoxicS. ciliataWhole plantEthanolParacetamol-induced hepatic damage in rats
AntimicrobialS. calvaRootsMethanolOral microflora: Streptococcus mutans, Lactobacillus acidophilus and Candida albicans
Anti-inflammatoryS. acmellaAerial partsEthanolLipopolysaccharide-activated murine macrophage model
Antimalarial, larvicidalS. mauritianaAerial partsMethanol extractAedes aegypti larvae
InsecticidalS. acmella Murr.Leaves and flowersAqueousChilo partellus
DiureticS. acmellaFlowersCWEHydrated rats
AntioxidantS. acmella Murr.Aerial partsChloroform, hexane, ethyl actate, methanol2,2-Diphenyl-1-picrylhydrazyl and superoxide dismutase assay
AntimicrobialS. americanaWhole plantAqueous, ethanol and hexaneStaphylococcus aureus, Streptococcus hemolytic, Bacillus cereus, Pseudomonas aeruginosa and Escherichia coli
AntipyreticS. acmella Murr.NAAqueousAspirin-treated rats
DiureticS. acmellaLeavesPetroleum ether, chloroform and ethanolHydrated Wistar albino rats
AntimicrobialS. paniculataLeavesNABacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida
albicans and Microsporum gypseum
AntimicrobialS. mauritianaRoots and flowersNAStaphylococcus, Enterococcus, Pseudomonas, Escherichia and Klebsiella, Salmonella
AntimicrobialS. mauritianaRoots and flowersNACandida species and Aspergillus species
AntimicrobialS. acmella Linn.Flower headsPetroleum etherFusarium oxysporium, F. moniliformis, Aspergillus Niger and A. paraciticus
Local anaestheticS. acmella Murr.NAAqueousXylocaine-induced guinea pig and frog
Antimalarial, larvicidalS. mauritianaLeavesCrude powderA. gambiae, Culex larvae
Anti-inflammatoryS. acmellaAerial partsAqueousCarragenan-induced paw edema in rats
AphrodisiacS. acmella L. Murr.FlowersEthanolNitric oxide release in human corpus cavernosum cell line and penile erection in rats
InsecticidalS. acmellaNANAPeriplaneta Americana
HIV-1 protease inhibitorS. acmella L.Whole plantChloroform, methanol and waterIn vitro HIV-1 protease solution assay method
AnalgesicS. acmellaAerial partsAqueousAcetic acid-induced writhing response in albino mice
Pancreatic lipase-inhibitoryS. acmellaFlowersEthanolIn vitro test
VasorelaxantS. acmella Murr.Aerial partsChloroform, hexane, ethyl acetate, methanolPhenethylephrine-induced rat
AntimutagenicS. calvaNAChloroformAmes Salmonella/microsome assay
ConvulsantS. acmellaWhole plantHexaneElectroencephalograph response of rats

Active chemicals

The most important taste-active molecules present are fatty acid amides such as spilanthol, which is responsible for the trigeminal and saliva-inducing effects of the plant. It also contains stigmasteryl-3-O-b-D-glucopyranoside and a number of triterpenes. The isolation and total synthesis of the active ingredients have been reported.

Biological pest control

Extracts were bioassayed against yellow fever mosquito and corn earworm moth larvae. The spilanthol proved effective at killing mosquitoes, with a 24-hour LD100 of 12.5 µg/mL, and 50% mortality at 6.25 µg/mL. The mixture of spilanthol isomers produced a 66% weight reduction of corn earworm larvae at 250 µg/mL after 6 days.