Neoclerodane Diterpenoids from Ajuga taiwanensis

A newly developed UPLC-MS/MS method for simultaneous quantitative analysis of ajuforrestin A, ajuforrestin B, ajugamacrin and 8-O-acetylharpagide derived from Ajuga plants in mice blood and the in vivo pharmacokinetics

OBJECTIVE

To develop a sensitive and fast detection method via ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to assess the concentration of ajuforrestin A, ajuforrestin B, ajugamacrin and 8-O-Acetylharpagide primarily derived from Ajuga plants in mice blood and their pharmacokinetics.

METHODS

Single protein precipitation with high-proportioned acetonitrile is chosen for sample clean-up. The UPLC HSS T3 (2.1 mm × 100 mm, 1.8 µm) column with a mobile phase in gradient elution mode at the flow rate of 0.4 mL/min was used for sample separation. Acetonitrile was selected as the organic phase solution and water containing 0.1% formic acid was chosen as the aqueous solution. A tandem mass spectrometer containing an electrospray ionization (ESI) source in the positive ionization mode was used to detect four compounds via multiple reaction monitoring (MRM).

RESULTS

The calibration curves (5-1000 ng/mL) of four compounds were linear with correlation coefficients > 0.997. The matrix effects, accuracy, precision, and recovery were all within permissible scope.

CONCLUSIONS

In this approach, the corresponding pharmacokinetic parameters were successfully clarified in mouse for the first time, which provided a theoretical basis for the improvement of the standard of Ajuga plants and the safety of clinical medication. Furthermore, this method may provide the UPLC-MS/MS evidence for the differentiation of the main close relative varieties of genus Ajuga according to these plants contain different mixtures of the four marker compounds.

Anti-inflammatory neo-Clerodane Diterpenoids from Ajuga pantantha

Eight new neo-clerodane diterpenoids (1-8) were acquired from the aerial parts of Ajuga pantantha. Spectroscopic data analysis permitted the definition of their structures, and experimental and calculated electronic circular dichroism data were used to define their absolute configurations. Compounds 2 and 4-8 were found to have NO inhibitory effects with IC₅₀ values of 20.2, 45.5, 34.0, 27.0, 45.0, and 25.8 μM, respectively. The more potent compounds 2, 6, and 8 were analyzed to establish their anti-inflammatory mechanism, including regulation of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins as well as their binding interactions with the two proteins.

Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicology of Species from the GenusAjugaL.: A Systematic Review

The present review is aimed at providing a comprehensive summary of the botanical characteristics, ethnomedicinal uses, phytochemical, pharmacological, and toxicological studies of the genus Ajuga L. The extensive literature survey revealed Ajuga L. species to be a group of important medicinal plants used for the ethnomedical treatment of rheumatism, fever, gout, sclerosis, analgesia, inflammation, hypertension, hyperglycemia, joint pain, palsy, amenorrhea, etc., although only a few reports address the clinical use and toxicity of these plants. Currently, more than 280 chemical constituents have been isolated and characterized from these plants. Among these constituents, neo-clerodane diterpenes and diterpenoids, phytoecdysteroids, flavonoids, and iridoids are the major bioactive compounds, possessing wide-reaching biological activities both in vivo and in vitro, including anti-inflammatory, antinociceptive, antitumor, anti-oxidant, antidiabetic, antimicrobial, antifeedant, antidiarrhoeal, hypolipidemic, diuretic, hypoglycaemic, immunomodulatory, vasorelaxant, larvicidal, antimutagenic, and neuroprotective activity. This review is aimed at summarizing the current knowledge of the ethnomedicinal uses, phytochemistry, biological activities, and toxicities of the genus Ajuga L. to reveal its therapeutic potentials, offering opportunities for future researches. Therefore, more focus should be paid to gathering information about their toxicology data, quality-control measures, and the clinical application of the bioactive ingredients from Ajuga L. species.

Isolation and Identification of Neo-Clerodane Diterpenes from Ajuga Nipponensis Makino

An extract of the aerial parts of Ajuga nipponensis Makino was examined by HPLC for neo-clerodane diterpenes. The suitability of reversed-phase HPLC for the semi-preparative fractionation of this extract was explored, resulting in the isolation of two new neo-clerodane diterpenes, which we have named ajuganipponin A, (12S)-1β,6α,19-triacetoxy-4α,18-epoxy-12-tigloyl-neo-clerod-13-en-15,16-olide (AJNP A, 1), and ajuganipponin B, (12S)-6α,19-diacetoxy-4α,18-epoxy-12-tigloyl-neo-clerod-13-en-15,16-olide (AJNP B, 6). In addition, ajugamarins A2 and F4, ajugamacrin B, ajugacumbin A and ajugatakasin A, were newly isolated compounds from A. nipponensis, along with the previously reported ajugamarins A1, B2 and L2 (ajugacumbin B). The structures of all the isolated compounds were unambiguously elucidated based on extensive NMR spectral studies (one and two-dimensional experiments) and their reversed-phase chromatographic behavior was established. The antifeedant activity of the isolated diterpenes against Spodoptera littoralis is also reported here.

Neo-clerodane diterpenes and phytoecdysteroids from Ajuga decumbens Thunb. and evaluation of their effects on cytotoxic, superoxide anion generation and elastase release in vitro

Five novel compounds, including four neoclerodane diterpenoids, named ajugacumbins KN (1-4) along with a phytoecdysterone, named ajugacetalsterone E (5), were isolated from the whole herbs of Ajuga decumbens (Labiatae). Their structures were elucidated on the basis of detailed spectroscopic analysis including IR, HRESIMS, CD, 1D and 2D NMR spectroscopic experiments. Compounds 1-5 were evaluated for their cytotoxic activities and the effects on superoxide anion generation and elastase release in FMLP/CB-induced human neutrophils.

Chemical and pharmacological research on the plants from genus Ajuga

The genus

Clerodane diterpenes: sources, structures, and biological activities

Covering: 1990 to 2015The clerodane diterpenoids are a widespread class of secondary metabolites and have been found in several hundreds of plant species from various families and in organisms from other taxonomic groups. These substances have attracted interest in recent years due to their notable biological activities, particularly insect antifeedant properties. In addition, the major active clerodanes of Salvia divinorum can be used as novel opioid receptor probes, allowing greater insight into opioid receptor-mediated phenomena, as well as opening additional areas for chemical investigation. This article provides extensive coverage of naturally occurring clerodane diterpenes discovered from 1990 until 2015, and follows up on the 1992 review by Merritt and Ley in this same journal. The distribution, chemotaxonomic significance, chemical structures, and biological activities of clerodane diterpenes are summarized. In the cases where sufficient information is available, structure activity relationship (SAR) correlations and mode of action of active clerodanes have been presented.

neo-Clerodane Diterpenoids from Ajuga macrosperma var. breviflora

Six new naturally occurring ajugarin-like neo-clerodane diterpenoids, ajugaflorins A-F, along with six known compounds [the parent ajugarin I, ajugalides B and C, ajugamarin F4, ajugamacrin E, and ajugatakasin B] were isolated from A. macrosperma var. breviflora. The structures were elucidated by extensive NMR spectroscopic and MS analyses and comparison with data previously reported.

A new neo-clerodane diterpene from Ajuga decumbens

A new neo-clerodane diterpene, named ajugacumbin J (1), together with 13 known compounds (2-14) was isolated from Ajuga decumbens. The structure of ajugacumbin J (1) was elucidated by 1D and 2D NMR spectra and MS. Ajugacumbin J (1) and ajugacumbin D (5) exhibited inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages with an IC50 value of 46.2 and 35.9 μM, respectively.

Bioactive neo-clerodane diterpenoids from the whole plants of Ajuga ciliata Bunge

Ten new neo-clerodane diterpenes, ajugaciliatins A-J (1-5, 8-12), along with 17 known analogues (6, 7, 13-27) were isolated from the whole plants of Ajuga ciliata Bunge. Their structures were elucidated by spectroscopic data analysis (IR, ESIMS, HRESIMS, 1D and 2D NMR), and the configuration of 1 was confirmed by X-ray crystallography. All of the compounds were assessed for neuroprotective effects against MPP(+)-induced neuronal cell death in dopaminergic neuroblastoma SH-SY5Y cells. Compounds 2, 6, 7, 9, 10, 15-17, 19, and 20 exhibited moderate neuroprotective effects.

Diterpene Lactones with Labdane, Halimane and Clerodane Frameworks

The labdane, halimane and clerodane type diterpenoids are compounds that have been isolated in plants of several families. These molecules and their derivatives with a lactone group on the side chain or on the decaline system, have a great interest because of their biological properties as insect antifeedant, antiviral, cytotoxic and trypanocidal. The scope of this review is lactones diterpenoids with labdane, halimane and clerodane frameworks.

Diterpenoids

This review covers the isolation and structures of diterpenoids, including labdanes, clerodanes,pimaranes, abietanes, kauranes, cembranolides, taxanes and marine diterpenoids. The literature from January to December 2005 is reviewed, and 195 references are cited.

A new phytoecdysteroid from Ajuga taiwanensis

A new phytoecdysteroid, namely ajugalide-E (1), together with twenty five known compounds were isolated from Ajuga taiwanensis collected from Tainan, Taiwan. Their structures were determined by spectral analysis including high resolution one- and two-dimensional NMR spectroscopy.