Effects of lovastin, fosmidomycin and methyl jasmonate on andrographolide biosynthesis in the Andrographis paniculata

Andrographolide is a diterpene secondary metabolite product of Andrographis paniculata. It has been known to be a pharmaceutically important compound synthesized via the cytosolic mevalonate (MVA) and the plastidial 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways. To understand the biosynthetic pathway of andrographolide biosynthesis in Andrographis paniculata, lovastatin, fosmidomycin and methyl jasmonate (MeJA) were used to inhibit the key enzymes 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), and 1-deoxy-d-xylulose-5-phosphate reducto-isomerase (DXR) involved in the synthesis of andrographolide in the MVA and MEP pathways, respectively. The inhibition of andrographolide accumulation was linked with the expression level of the studied regulatory genes, 3-hydroxy-3-methyl glutaryl coenzyme A synthase (hmgs), 3-hydroxy-3-methyl glutaryl coenzyme A reductase (hmgr), 1-deoxyxylulose-5-phosphate synthase (dxs), 1-deoxyxylulose-5-phosphate reductoisomerase (dxr), 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase (hds),1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (hdr), 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase(isph), isopentenyl diphosphate isomerase (ipp), geranylgeranyl diphosphatesynthase (ggps) of the MVA and MEP pathways. The pathways associated transcript expression level, and andrographolide biosynthesis was significantly modulated by the inhibitors indicating that the andrographolide biosynthesis is strongly responsive at the transcriptional level. The results demonstrated that both pathways can contribute to the biosynthesis of andrographolide in A. paniculata. Both hmgr and dxr played a critical role consistent with some crossover between MVA and MEP pathways in andrographolide biosynthesis.