Biological Science: Research Developments and Innovations Vol. 4

The genus Coleus (Lamiaceae) includes several medicinally important species used in traditional medicine. This review synthesises current information on Coleus forskohlii (Willd.) Briq., Coleus vettiveroides K.C. Jacob, and Coleus amboinicus Lour., with emphasis on in vitro propagation and phytochemical characteristics. C. forskohlii is an important source of forskolin, a labdane diterpene associated with cardiovascular, respiratory, ophthalmic, and metabolic effects. C. vettiveroides is valued for its aromatic roots and essential oils, whereas C. amboinicus contains volatile constituents, particularly thymol and carvacrol, with reported antimicrobial and anti-inflammatory activities. The review compares explant selection, surface sterilisation, culture media, plant growth regulators, callus induction, shoot multiplication, rooting, acclimatisation, hairy-root culture, genetic-fidelity assessment, and bioreactor approaches. It also summarises primary and secondary metabolites, including alkaloids, flavonoids, phenolics, terpenoids, essential oils, and related bioactive constituents, together with the analytical methods used for their detection and quantification. Particular attention is given to differences in metabolite accumulation among intact plants, regenerated tissues, callus, root cultures, and hairy roots, together with challenges in contamination control and commercial scale-up. Available evidence indicates that propagation and phytochemical protocols are more extensively developed for C. forskohlii and C. amboinicus than for C. vettiveroides. The review therefore highlights the need for improved standardisation of culture conditions, analytical methods, and scale-up strategies to support conservation, sustainable propagation, and consistent phytochemical production.