A comparative study of two clerodane diterpenes from Baccharis trimera (Less.) DC. on the influx and mobilization of intracellular calcium in rat cardiomyocytes

Baccharis trimera (Less.) D.C. (Asteraceae) is a medicinal species native to South America and used in Brazilian folk medicine to treat gastrointestinal and liver diseases, kidney disorders and diabetes. The aqueous extract (AE) of the aerial parts of this species presented two mainly constituents: the ent-clerodane diterpene (Fig. 1) and the neo-clerodane diterpene (Fig. 2). The objective of this work was to study their activities on the blockade of Ca²⁺-induced contractions in KCL-depolarized rat portal vein preparations, and on the influx and mobilization of cytosolic calcium in rat cardiomyocytes by fluorescence measurements. The results showed that both the neo- and the ent-clerodane diterpenes reduced the maximal contractions induced by CaCl₂, in KCl depolarized rat portal vein preparations, without modifying the EC₅₀. The data on the concentration of cytosolic calcium ([Ca²⁺]_c) showed that, while the neo-clerodane diterpene stimulates the mobilization of [Ca²⁺]_c in rat cardiomyocytes, this effect was not observed with the ent-clerodane diterpene. On the other hand, the influx of calcium was not altered by the neo-clerodane diterpene, but was reduced in the presence of the ent-clerodane diterpene, indicating that this compound induces a blockade of the voltage-dependent calcium channels.     

neo-Clerodane diterpenes from Ajuga ciliata and their inhibitory activities on LPS-induced NO production

Two new neo-clerodane diterpenes, (12S)-6α-acetoxy-4α,18-epoxy-12-hydroxy-19-tigloyloxy-neo-clerod-13-en-15,16-olide (1) and 6α,18-diacetoxy-4α-hydroxy-19-tigloyloxy-neo-clerod-13-en-15,16-olide (2), along with three known analogs (3–5) have been isolated from the whole plants of Ajuga ciliata Bunge. Their structures were elucidated on the basis of spectroscopic data analyses (IR, ESI-MS, HR-ESI-MS, HMQC, HMBC, COSY, and NOESY). The inhibitory activities on LPS-induced NO production of these diterpenes were evaluated and compounds 1 and 5 showed inhibitory effects.     

neo-Clerodane diterpenoids from the leaf exudate of Dodonaea angustifolia

Phytochemical investigation of the leaf surface exudate of Dodonaea angustifolia L.f. yielded two new neo-clerodane diterpenes, neo-clerodan-3,13-dien-16,15:18,19-diolide (mkapwanin) and 15-methoxy-neo-clerodan-3,13-dien-16,15:18,19-diolide (15-methoxymkapwanin). In addition, ten known compounds were identified. The structures were determined on the basis of spectroscopic evidence. This additional chemical information could contribute towards solving the taxonomical controversy that exists between Dodonaea angustifolia and Dodonaea viscosa Jacq., which are morphologically similar.     

Stachaegyptin A-C: Neo-clerodane diterpenes from Stachys aegyptiaca

Phytochemical investigation of Stachys aegyptiaca resulted in the characterization of three new diterpenes (1-3) together with eleven known compounds including four neo-clerodane diterpenes and seven flavonoid aglycones. Structure elucidation was performed by spectroscopic analysis by HRFABMS, 1D and 2D NMR and X-ray. Isolated compounds were screened for anti-inflammatory activity using a lipopolysaccharide-induced nitric oxide inhibition assay employing murine macrophage cells. Among the assayed compounds, 13 (calycopterin) showed a concentration-dependent inhibition of LPS-induced nitric oxide release with a IC₅₀ of 62.5 μM.     

Teugin,a neo-clerodane diterpenoid from Teucrium fragile

From the aerial part of Teucrium fragile a new neo-clerodane diterpenoid, teugin, has been isolated. Its structure, 15,16-epoxy- 2β,6β-dihydroxy-neo-cleroda-3,13(16),14-triene-18,19:20,12S-diolide, was established mainly by spectroscopic means.     

Diterpenoids from Ajuga chamaepitys: Two neo-clerodane derivatives

From the whole plant of Ajuga chamaepitys two new neo-clerodane diterpenoids, ajugapitin and its dihydro derivative, have been isolated. Their     

Antifeedant activity of neo-clerodane diterpenoids from Teucrium fruticans and derivatives of fruticolone

The antifeedant activity of three neo-clerodane diterpenoids, fruticolone, isofruticolone and fruticolide from Teucrium fruticans was assessed using larvae of Spodoptera littoralis. Isofruticolone was one of the most potent of the Teucrium derived neo-clerodanes. Chemical modification of functional groups on fruticolone showed that its activity could be enhanced.     

Neo-clerodane diterpenoids and other constituents from Baccharis species

A new neo-clerodane dilactone, desoxyarticulin, and dihydrotucumanoic acid, together with other known compounds, were isolated from Baccharis pedicellata and Baccharis marginalis. The structures of the new compounds were elucidated by spectroscopic methods.     

Lasianthin,a neo-clerodane diterpenoid from Salvia lasiantha

From the aerial part of Salvia lasiantha a neo-clerodane diterpenoid, lasianthin, was isolated. The structure of this compound was established by spectroscopic means and X-ray diffraction analysis.     

Clerodane diterpenoids from Portulaca cv jewel

Three trans-clerodane diterpenes were isolated from the aerial part of the Portulaca cv Jewel. Their structures were elucidated by spectroscopic methods and chemical correlations.     

Neo-clerodane diterpenoids from Ajuga pseudoiva

From the whole plant of Ajuga pseudoiva two epimeric neo-clerodane diterpenoids, 2-acetylivain I and its C-2 epimer 14,15-dihydro-ajugapitin, have been isolated. The structures were established by spectroscopic and chemical means. 2-Acetylivain I had not been previously reported, while its C-2 epimer had been isolated from Ajuga chamaepitys.     

Effect of nutritional factors on cryptotanshinone and ferruginol production by cell suspension cultures of Salvia miltiorrhiza

The effects of the components of Murashige-Skoog (MS) medium on the production of the diterpenes cryptotanshinone and ferruginol in cell suspension cultures of Salvia miltiorrhiza were examined. Sucrose, a nitrogen source and thiamine were needed for the production of these compounds, and phosphate, MnSO₄ and kinetin showed slight beneficial effects. All the other components of MS medium were found to be either unnecessary or inhibitory for the production of these compounds, when tested separately. A revised medium for the production of cryptotanshinone, a clinically active principle in this plant, was designed.     

Hastifolins A–G,antifeedant neo-clerodane diterpenoids from Scutellaria hastifolia

From the aerial parts of Scutellaria hastifolia, family Lamiaceae (Labiatae), seven neo-clerodane diterpenoids (hastifolins A–G) were isolated. The products are similar to the known scuteparvin and are characterized by being trans-cinnamoyl derivatives. Structures and stereochemistry were determined by intensive NMR investigation. Six of the products form three pairs of epimers at C-13. Hastifolins A–C showed significant antifeedant activity.     

Teucretol,a neo-clerodane diterpenoid from Teucrium creticum

From the aerial parts of Teucrium creticum a new neo-clerodane diterpenoid, teucretol, has been isolated, together with the previously known diterpenoids 6,19- diacetylteumassilin, 19-acetylgnaphalin and teucjaponin B. The structure of teucretol, 6,19-diacetoxy-4α,18;15,16-diepoxy-neo-cleroda-13(16),14-diene-12ξ,20-diol, was established by chemical and spectroscopic means.     

Establishment of callus,cell suspension and shoot cultures of Leonurus cardiaca L. and diterpene analysis

Summary Callus cultures, cell suspension cultures and shoot cultures of Leonurus cardiaca L. (Motherwort) were established and growth conditions optimized. Shoot cultures showed constant growth whether in the dark or under continuous light, accumulating varying amounts of the furanic labdane diterpenes leosibiricin, preleosibirin, leosibirin and isoballotenol acetate, which are also present in the soil-grown plants. Only traces of leosibiricin were detected in callus cultures, while cell suspension cultures did not produce any furanic diterpenes. A small amount of furanic labdane diterpenes was found in the medium of shoot cultures. Callus and shoot culture induction of several other Lamiaceae species is also described.Abbreviations 2 4-D 2,4-dichlorophenoxyacetic acid - BAP benzylaminopurine - GA₃ gibberellic acid - HPLC high pressure liquid chromatography - NAA naphthyl acetic acid - TLC thin layer chromatography     

neo-Clerodane diterpenoids from Ajuga: structural elucidation and biological activity

The presence of several types of allelochemicals has been reported from Ajuga, a Labiatae genus comprising more than 40 species of wide distribution in extratropical regions of both hemispheres. The genus is of great medicinal and economic importance and among the biological properties of the secondary metabolites, the antifeedant activity against pest insects appears to be related to the presence of neo-clerodane type diterpenes. This review focuses on the isolation and structural elucidation of this type of compounds from Ajuga species and the hemisynthetic compounds of closely related structure obtained. The reported biological activity of crude extracts and isolated diterpenes will be briefly commented.

Scutelinquanines A–C,three new cytotoxic neo-clerodane diterpenoid from Scutellaria barbata

Three new neo-clerodane diterpenoids, named scutelinquanines A–C (1–3), were isolated from the whole plant of Scutellaria barbata. Their structures were established on the basis of detailed spectroscopic analyses. In vitro, the isolated three new compounds showed significant cytotoxic activities against three human cancer lines (HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells), and gave IC₅₀ values in the range 2.7–6.7 μM.     

Enhanced production of camptothecin and biological preparation of <Emphasis Type="Italic">N</Emphasis><Superscript>1</Superscript>-acetylkynuramine in <Emphasis Type="Italic">Camptotheca acuminata</Emphasis> cell suspension cultures

The Camptotheca acuminata cell suspension cultures were established to produce the well-known antitumor monoterpene indole alkaloid camptothecin (CAM). Most CAM was present in the broth of the C. acuminata cell suspension cultures. The CAM production was evidenced to be attenuated when the C. acuminata cell suspension cultures were continuously subcultured and grown under identical axenic conditions. A practical cryopreservation and recovery procedure was established to maintain the C. acuminata cell suspension cultures. Biotic and abiotic elicitors were administrated to the C. acuminata cell suspension cultures to restore and enhance CAM production. Of them, sorbitol, a well-known hyperosmotic stressor, was proven to be the most effective elicitor that stimulates a ～500-fold increase of CAM production. The committed biosynthetic precursors of CAM, tryptamine and secologanin, were feed to the C. acuminata cell suspension cultures and the CAM production is not remarkably increased. However, N ¹-acetylkynuramine (NAK), an important metabolite of kynuramine pathway, was isolated and identified from the cell suspension cultures feeding with tryptamine. The present work provides an efficient method to produce CAM and NAK using the C. acuminata cell suspension cultures. The biotransformation of tryptamine to NAK sheds lights on the biosynthetic formation of the pyrroloquinoline moiety of CAM.     

Rearranged abietane diterpenoid hydroquinones from aerial parts of Ajuga decumbens Thunb

Four new rearranged abietane diterpenoid hydroquinones, ajudecumins A–D (1–4), together with two known rearranged abietane diterpenoids, three neo-clerodane diterpenoids, four megastigmane derivatives, two flavonoids as well as a bisabolene sesquiterpenoid were isolated from the aerial parts of Ajuga decumbens. Their structures were established on the basis of extensive spectroscopic analysis and the stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis. Among the diterpenoids, compounds 1 and 3 exhibited moderate inhibitory activity on the proliferation of human breast cancer MCF-7 cells.