Plant tissue culture of cat whiskers (Orthosiphon aristatus Blume Miq): A review of secondary metabolite production and micropropagation

Abstract

Background: The cat whiskers plant (Orthosiphon aristatus Blume Miq) is widely used as a raw material in traditional medicine for one of its many properties, i.e. antiviral activity. Three varieties of cat whiskers grow in Indonesia, classified according to the colour of their flower: white, white-purple, and purple. The purple variety of cat whiskers is endangered, so it is necessary to propagate this plant.    Objectives: This research aimed to obtain appropriate protocols for plant propagation and production of active compounds of cat whiskers by in vitro culture.    Methods: Data were collected from various online journal sites such as PubMed, ResearchGate, and Scopus. This review discusses several aspects, including callus induction efforts, modification of cell suspension cultures, and efforts to propagate the cat whiskers plant by in vitro culture.    Results: Callus induction of white cat whiskers with purple and purple hues could take place on Murashige and Skoog (MS) media added with growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) 0.4 mg/L. Suspension culture medium (MS+ 2,4-D 1 mg/L + NAA 1 mg/L) can increase cell biomass and rosmarinic acid levels. Media MS + 6-benzyl amino purine (BAP) 3 mg/L + 1-naphthaleneacetic acid (NAA) 2 mg/L can induce the growth of shoots of white cat whiskers with purple and purple patterns. Root induction of the two varieties of cat whiskers could take place on MS + Indole-3-butyric acid (IBA) 0.75 mg/L medium.   Conclusion: Efforts to produce secondary metabolites and plant propagation of cat whiskers by in vitro culture have been successful. It is necessary to enhance the production and propagation using bioreactors to yield more active compounds and raw materials of the cat whiskers plant.