Comprehensive review on phytochemistry and in vitro biotechnology of Coleus forskohlii

Abstract

Coleus forskohlii is an important medicinal plant which has a great role in Indian Ayurvedic medicine. It is the only source of the alkaloid forskolin the plant kingdom. It has excellent potential in the drug trade. It is used as a stomach aid and in treating intestinal disorders. This article reviews the effect of different sources of explants, different agents of sterilization, various media composition on micropropagation of the crop of high medicinal value. The best source of explants for initiation of cultures was the nodal segments of Coleus, since they withstood the sterilization process better than apical shoots, exhibiting maximum survival frequency. Simultaneously, when nodal segments were used as explants, shoots multiplied at a rate of 12 fold every six weeks. Sterilization with HgCl₂ shows a good response; however, prolonged sterilization time tends to show browning. In most of the study, Proline was effective for avoiding the browning during in vitro regeneration of Coleus forskohlii. The maximum percentage of shoot induction from the nodal segment was achieved on the medium containing BA (2 mg/l) and NAA (1 mg/l). Among two cytokinins (BAP and kinetin), BAP (2.0 mg/ l) was superior for the regeneration of shoots in Coleus. IAA (1.0 mg/l) was a prominent hormone for rooting of regenerated shoots.