In vitro production of spilanthol from Spilanthes acmella Murr.: State of the art and future prospect

Spilanthes acmella Murr., commonly known as toothache plant, is a well-known traditional plant of India. It has been demonstrated for a wide array of biological activities such as antifungal, antipyretic, bio-insecticide, antioxidant, aphrodisiac, analgesic, pancreatic lipase inhibitor, antimicrobial, diuretic, vasorelaxant and anti-inflammatory effects. These attributes are mainly due to the presence of an alkylamide, spilanthol. With increase in awareness about spilanthol therapeutic properties, industrial demand for this compound has also increased. Currently, spilanthol based industrial products are produced by collecting field grown plants. The utilization of huge quantities of whole plant parts is alarming as it can reduce local plant populations and erode genetic diversity. Moreover, the plants growing in wild undergo various climatic and environmental fluxes that may lead to change in their chemical profile. In vitro cultures have been viewed as promising alternatives to whole plant extraction for obtaining spilanthol, irrespective of seasons and regions, offering stable and consistent production. However, the research on in vitro spilanthol production is in its infancy and requires culture and process optimization for the development of a commercially feasible process. This review states the present status and future challenges of plant tissue culture for spilanthol production.