abietane and ferruginol

We identify two ferruginol synthases and a 11-hydroxyferruginol synthase from a traditional Chinese medicinal herb Isodon lophanthoides and propose their involvement in two independent abietane diterpenoids biosynthetic pathways. Isodon lophanthoides is a traditional Chinese medicinal herb rich in highly oxidized abietane-type diterpenoids. These compounds exhibit a wide range of pharmaceutical activities, yet the biosynthesis is barely known. Here, we describe the screening and functional characterization of P450s that oxidize the abietane skeleton abietatriene. We mainly focused on CYP76 family and identified 12 CYP76AHs by mining the RNA-seq data of I. lophanthoides. Among the 12 CYP76AHs, 6 exhibited similar transcriptional expression features as upstream diterpene synthases, including root or leaf-preferential expression pattern and highly MeJA inducibility. These six P450s were considered as first-tier candidates and functionally characterized in yeast and plant cells. In yeast assays showed that both CYP76AH42 and CYP76AH43 were ferruginol synthases hydroxylating the C12 position of abietatriene, whereas CYP76AH46 was characterized as a 11-hydroxyferruginol synthase which catalyzes two successive oxidations at C12 and C11 of abietatriene. Heterologous expression of three CYP76AHs in Nicotiana benthamiana resulted in the formation of ferruginol. qPCR analysis showed CYP76AH42 and CYP76AH43 were mainly expressed in the root, which was consistent with the distribution of ferruginol in the root periderms. CYP76AH46 was primarily expressed in the leaves where barely ferruginol or 11-hydroxyferruginol was detected. In addition to distinct organ-specific expression pattern, three CYP76AHs exhibited different genomic structures (w or w/o introns), low protein sequence identities (51-63%) and were placed in separate subclades in the phylogenetic tree. These results suggest that the identified CYP76AHs may be involved in at least two independent abietane biosynthetic pathways in the aerial and underground parts of I. lophanthoides.

Topics: Abietanes; Cytochrome P-450 Enzyme System; Diterpenes; Isodon; Phylogeny; Saccharomyces cerevisiae

Topics: Abietanes; Agrobacterium; Biomass; Bioreactors; Culture Media; Diterpenes; Plant Roots; Plants, Genetically Modified; Salvia; Transformation, Genetic

Abietane diterpenoids are naturally occurring plant metabolites with a broad spectrum of biological effects including antibacterial, antileishmanial, antitumor, antioxidant, as well as antiinflammatory activities. Recently, we found that some analogues of natural ferruginol ( 2 ) actively inhibited dengue virus 2 (DENV-2) replication. Due to the similarity with DENV, we envisaged that abietane diterpenoids would also be active against Zika virus (ZIKV). Six selected semi-synthetic abietane derivatives of (+)-dehydroabietylamine ( 3 ) were tested. Cytotoxicity was determined by MTT assay in Vero cells. In vitro anti-ZIKV (clinical isolate, IMT17) activity was evaluated by plaque assay. Interestingly, these molecules showed potential as anti-ZIKV agents, with EC50 values ranging from 0.67 to 18.57 µM, and cytotoxicity (CC50 values) from 2.56 to 35.09 µM. The 18-Oxoferruginol (8) (EC50 = 2.60 µM, SI = 13.51) and 12-nitro-N-benzoyldehydroabietylamine (9) (EC50= 0.67 µM, SI = 3.82) were the most active compounds, followed by 12-hydroxy-N-tosyldehydroabietylamine ( 7 ) (EC50 = 3.58 µM, SI = 3.20) and 12-hydroxy-N,N-phthaloyldehydroabietylamine ( 5 ) (EC50 = 7.76 µM, SI = 1.23). To the best of our knowledge, this is the first report on anti-Zika virus properties of abietanes.

Topics: Abietanes; Animals; Chlorocebus aethiops; Plant Extracts; Vero Cells; Zika Virus; Zika Virus Infection