Isoprenylated flavonoids and clerodane diterpenoids from Dodonaea viscosa

Phytochemical investigation of the aerial parts of Dodonaea viscosa led to the isolation of six new compounds including four isoprenylated flavonoids,dodovisones A-D(1-4),and two clerodane diterpenoids,dodovislactones A and B(5 and 6).Their structures were established by extensive spectroscopic analysis.

The genomes of medicinal skullcaps reveal the polyphyletic origins of clerodane diterpene biosynthesis in the family Lamiaceae

The presence of anticancer clerodane diterpenoids is a chemotaxonomic marker for the traditional Chinese medicinal plant Scutellaria barbata,although the molecular mechanisms behind clerodane biosynthesis are unknown.Here,we report a high-quality assembly of the 414.98 Mb genome of S.barbata into 13 pseudochromosomes.Using phylogenomic and biochemical data,we mapped the plastidial metabolism of kaurene(gibberellins),abietane,and clerodane diterpenes in three species of the family Lamiaceae(Scutellaria barbata,Scutellaria baicalensis,and Salvia splendens),facilitating the identification of genes involved in the biosynthesis of the clerodanes,kolavenol,and isokolavenol.We show that clerodane biosynthesis evolved through recruitment and neofunctionalization of genes from gibberellin and abietane metabolism.Despite the assumed monophyletic origin of clerodane biosynthesis,which is widespread in species of the Lamiaceae,our data show distinct evolutionary lineages and suggest polyphyletic origins of clerodane biosynthesis in the family Lamiaceae.Our study not only provides significant insights into the evolution of clerodane biosynthetic pathways in the mint family,Lamiaceae,but also will facilitate the production of anticancer clerodanes through future metabolic engineering efforts.

Clerodane diterpenoids with potential anti-inflammatory activity from the leaves and twigs of Callicarpa cathayana

Phytochemical investigation of the leaves and twigs of Callicarpa cathayana led to the isolation of six new clerodane diterpenoids,cathayanalactones A-F(1-6),together with seven analogues(7-13).Their structures were established by extensive NMR analyses together with experimental and calculated ECD spectra analyses.Compounds 1,2,3,7 and 11 showed inhibitory activities on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.

Peltate glandular trichomes of Colquhounia seguinii harbor new defensive clerodane diterpenoids

Glandular trichomes produce a wide variety of secondary metabolites that are considered as major defensive chemicals against herbivore attack.The morphology and secondary metabolites of the peltate glandular trichomes of a lianoid Labiatae,Colquhounia seguinii Vaniot,were investigated.Three new clerodane diterpenoids,seguiniilactones A-C（1-3）,were identified through precise trichome collection with laser microdissection,metabolic analysis with ultra performance liquid chromatography-tandem mass spectrometer,target compound isolation with classical phytochemical techniques,structure elucidation with spectroscopic methods.All compounds showed significant antifeedant activity against a generalist plant-feeding insect Spodoptera exigua.Seguiniilactone A（1） was approximately 17-fold more potent than the commercial neem oil.a-Substituted α,β-unsaturated γ-lactone functionality was found to be crucial for strong antifeedant activity of this class of compounds.Quantitative results indicated that the levels of these compounds in the peltate glandular trichomes and leaves were sufficiently high to deter the feeding by generalist insects.Moderate antifungal activity was observed for seguiniilactone C（3） against six predominant fungal species isolated from the diseased leaves of C seguinii,while seguiniilactones A and B were generally inactive.These findings suggested that seguiniilactones A-C might be specialized secondary metabolites in peltate glandular trichomes for the plant defense against insect herbivores and pathogens.