New glycosides from ajuga decumbens

Metabolome-microbiome insights into therapeutic impact of 8-O-acetylharpagide against breast cancer in a murine model

Iridoid glycosides extract, which is the main active extract of Ajuga decumbens Thunb, has been proved to have anti-breast cancer activity in previous studies. However, it is still unknown whether 8-O-acetylharpagide, a main active compound in the extract, has anti-breast cancer activity. In this study, 4 T1 breast cancer mice model was first successfully established. Then the anti-breast cancer effect of 8-O-acetylharpagide was systematically investigated. Feces were collected for metabolomics and 16S rRNA analysis to assess the potential mechanism. The results showed that 8-O-acetylharpagide was effective in reducing 4 T1 mouse tumor volume and weight compared with the model group. Metabolome analysis revealed 12 potential metabolite biomarkers in feces, mainly involved in primary bile acid biosynthesis and arachidonic acid metabolism. The 16S rRNA sequencing results demonstrated that 8-O-acetylharpagide modulated the abundance of the intestinal flora in 4 T1 mice. Spearman correlation analysis showed that calcitriol and prostaglandin G2 strongly correlated with Akkermansia, Firmicutes and Muribaculum. Overall, the active compound 8-O-acetylharpagide could inhibit significantly breast cancer growth in 4 T1 breast cancer model mice. The mechanism of the anti-breast cancer effect of 8-O-acetylharpagide may be related to the regulation of primary bile acid biosynthesis and arachidonic acid metabolism and modulation of the abundance of Akkermansia and Firmicutes.

Diterpenoids from the Whole Plants of Ajuga nipponensis and Their Inhibition of RANKL-Induced Osteoclastogenesis

Two new diterpenoids, ajudecunoid A (1) and ajudecunoid B (14), along with thirteen known diterpenoids, were isolated from the whole plants of Ajuga nipponensis Makino. Their structures were elucidated by the extensive spectroscopic analysis (UV, IR, MS, and NMR). The absolute configurations of ajudecunoid A (1) and ajudecunoid B (14) were defined through analysis of X-ray crystallography. Fifteen compounds were evaluated for inhibition of the formation of osteoclasts in bone marrow-derived macrophages (BMM) cells. Two neo-clerodane diterpenoids ajuganipponin B (5) and (12S)-6α,19-diacetoxy-18-chloro-4α-hydroxy-12-tigloyloxy-neo-clerod-13-en-15,16-olide (12) showed significant inhibition of osteoclastogenesis with IC₅₀ values of 0.88 and 0.79 μM, respectively. Here we firstly reported diterpenoids with anti-osteoclastogenesis activity from A. nipponensis.

Harpagide: Occurrence in plants and biological activities - A review

In this review article, the occurrence of harpagide in the plant kingdom and its associated biological activities are presented and detailed for the first time. The presence of harpagide has been reported in several botanical families within Asteridae, and harpagide has been observed to exert a wide number of biological activities such as cytotoxic, anti-inflammatory, and neuroprotective. These results show how harpagide can be recovered from several natural sources for several pharmacological purposes even if there is a lot to still be studied. Nowadays, the interest is related to its presence in phytomedicines. Threfore, these studies are useful to support and validate the large use of several plants in the folklore medicine.

Characterisation of phenylethanoid glycosides by multiple-stage mass spectrometry

RATIONALE

Although phenylethanoid glycosides (PhGs) occur widely in plants, their characterisation by liquid chromatography/mass spectrometry (LC/MS) is less well studied than other phenolic glycosides such as flavonoid glycosides. The multiple-stage mass spectrometry (MSⁿ ) experiments required to improve the annotation of common verbascoside-type PhGs are described here.

METHODS

Deprotonated, ammoniated and sodiated molecules of nine PhGs were subjected to low-energy collision-induced dissociation (CID) in a hybrid ion trap/orbitrap mass spectrometer. Most experiments were recorded at nominal mass using the linear ion trap analyser for wider applicability in the plant metabolomics community. Data interpretation was supported by high-resolution orbitrap scanning of product ions. Comparative data was acquired on the same instrument by performing higher-energy collisional dissociation (HCD) in the C-trap.

RESULTS

Low-energy CID-MS² of the deprotonated and ammoniated molecules generated diagnostic product ions from which the molecular masses of the phenolic acid and phenylethanoid moieties, respectively, could be determined. The sugar at C-3' of the core glucose was preferentially lost from the sodiated molecule following CID-MS² , while CID-MSⁿ produced a sodiated product ion from ring cleavage of the core glucose bearing the sugar at C-6'. Evidence of a disaccharide substitution came from a sodiated disaccharide residue in CID-MSⁿ spectra.

CONCLUSIONS

The consistency of PhG dissociation following low-energy CID-MSⁿ of various ions is sufficient to enable annotation of verbascoside-type PhGs in LC/MS analyses of crude plant extracts. This can be achieved on a low-resolution instrument capable of MSⁿ .

A review on the structure and pharmacological activity of phenylethanoid glycosides

Phenylethanoid glycosides (PhGs) are compounds made of phenylethyl alcohol, caffeic acid and glycosyl moieties. The first published references about phenylethanoid glycosides concerned the isolation of echinacoside from Echinaceu ungustifolia (Asteraceae) in 1950 and verbascoside from Verbascum sinuatum (Scrophulariaceae) in 1963. Over the past 60 years, many compounds with these structural characteristics have been isolated from natural sources, and most of these compounds possess significant bioactivities, including antibacterial, antitumor, antiviral, anti-inflammatory, neuro-protective, antioxidant, hepatoprotective, and immunomodulatory activities, among others. In this review, we will summarize the phenylethanoid glycosides described in recent papers and list all the compounds that have been isolated over the past few decades. We will also attempt to present and assess recent studies about the separation, extraction, determination, and pharmacological activity of the excellent natural components, phenylethanoid glycosides.

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.

A new abietane diterpenoid glycoside from ajuga ovalifolia var. calantha

A new abietane diterpenoid glycoside, ajugaside B (1), along with three known compounds (2-4), were isolated from the whole plants of Ajuga ovalifolia var. calantha. The structure of the new compound (1) was elucidated by means of spectroscopic analyses (HRESIMS, IR, NMR and ECD). All of the isolated compounds were evaluated for their antitumor activities against MGC803, MCF-7, A549, HT29 and HepG2 cell lines. Compounds 3-4 showed moderate cytotoxicity against all tested cell lines with IC₅₀ values of 1.8-7.3 μM.

Bioactive Secondary Metabolites from the Aerial Parts of Buddleja macrostachya

A new iridoid glycoside, buddlemacroside A (1) and 15 known compounds, including 6-α-L-(4″- O-trans-p-coumaroyl)rhamnopyranosylcatalpol (2), 6-α-L-(2″-caffeoyl)rhamnopyranosylcatalpol (3), salidroside (4), echipuroside A (5), darendoside A (6), decaffeoylacteoside (7), acteoside (8), martynoside (9), 8-hydroxylinalool 3- O-β-D-glucopyranoside (10), 9- O-α-L-rhamnopyranosyl-4-hydroxy-cinnamic acid (11), apigenin (12), acacetin-7- O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (13), mimengoside C (14), buddlejasaponin Ia (15), and buddejasaponin I (16) were isolated from a methanol extract of the aerial parts of Buddleja macrostachya Benth. Their chemical structures were elucidated by extensive spectroscopic analyses, including MS and NMR spectra as well as by comparison with the data reported in the literature. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test showed that compounds 3 and 7-9 possess significant scavenging capacity, with SC50 values ranging from 6.9-19.6 μM. Compound 8 was shown to have potent inhibitory effect against the release of malondialdehyde (MDA) - the major product of the cellular lipid peroxidation, with IC50 value of 2.3 μM. Compounds 12 and 16 significantly inhibited nitrite production in LPS-stimulated BV2 microglia, with IC50 values of 14.2 and 11.4 μM, respectively. Furthermore, compound 16 showed cytotoxicity toward three human cancer cell lines, including SK-LU-1, MCF7, HepG2, with IC50 values in the range of 6.5-8.0 μM.

Chemical and pharmacological research on the plants from genus Ajuga

The genus

New Iridoid Glucosides from Caryopteris incana (Thunb.) Miq. and Their α-Glucosidase Inhibitory Activities

In our continued investigations of the plant Caryopteris incana, five new iridoid glucosides 1-5, including two cis-trans-isomers, 3 and 4, along with six known compounds 6-11, were isolated from the n-butyl alcohol (n-BuOH) soluble fraction of whole dried material of Caryopteris incana. Their structures were established by a combination of spectroscopic techniques, including 1D and 2D NMR and high resolution electrospray ionization mass spectroscopy (HR-ESI-MS). Furthermore, all isolates were evaluated for their yeast α-glucosidase inhibitory effects. Among these compounds, 4-8 and 10 exhibited potent inhibition of α-glucosidase.

Evaluation of in vitro antiprotozoal activity of Ajuga laxmannii and its secondary metabolites

Context Some Ajuga L. (Lamiaceae) species are traditionally used for the treatment of malaria, as well as fever, which is a common symptom of many parasitic diseases. Objective In the continuation of our studies on the identification of antiprotozoal secondary metabolites of Turkish Lamiaceae species, we have investigated the aerial parts of Ajuga laxmannii. Materials and methods The aerial parts of A. laxmannii were extracted with MeOH. The H2O subextract was subjected to polyamide, C18-MPLC and SiO2 CCs to yield eight metabolites. The structures of the isolates were elucidated by NMR spectroscopy and MS analyses. The extract, subextracts as well as the isolates were tested for their in vitro antiprotozoal activities against Plasmodium falciparum, Trypanasoma brucei rhodesiense, T. cruzi and Leishmania donovani at concentrations of 90-0.123 μg/mL. Results Two iridoid glycosides harpagide (1) and 8-O-acetylharpagide (2), three o-coumaric acid derivatives cis-melilotoside (3), trans-melilotoside (4) and dihydromelilotoside (5), two phenylethanoid glycosides verbascoside (6) and galactosylmartynoside (7) and a flavone-C-glycoside, isoorientin (8) were isolated. Many compounds showed moderate to good antiparasitic activity, with isoorientin (8) displaying the most significant antimalarial potential (an IC50 value of 9.7 μg/mL). Discussion and conclusion This is the first report on the antiprotozoal evaluation of A. laxmannii extracts and isolates. Furthermore, isoorientin and dihydromelilotoside are being reported for the first time from the genus Ajuga.

Stereochemistry of cleistanthane diterpenoid glucosides from Phyllanthus emblica

Theoretical calculated electronic circular dichroism and Mosher’s method were applied to elucidate the stereochemistry of cleistanthane diterpenoids.

Myrotheciumones: bicyclic cytotoxic lactones isolated from an endophytic fungus of Ajuga decumbens

Two new bicyclic lactones, myrotheciumones A (1) and B (2) which possessed a rare ring-fusion system were isolated from Myrothecium roridum (M. roridum), an endophytic fungus of the medicinal herb plant Ajuga decumbens (A. decumbens) via an in vitro cytotoxicity assay. Structures were deduced from 1D and 2D NMR (Nuclear magnetic resonance) data. Myrotheciumone A's in vitro cytotoxicity and apoptotic activity were evaluated and myrotheciumone A was shown to exert cytotoxicity via inducing apoptosis in cancer cell line.

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.

Pharmacokinetics of 8-O-acetylharpagide and harpagide after oral administration of Ajuga decumbens Thunb extract in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ajuga decumbens Thunb is a medicinal plant native to China popularly used to treat chronic pelvic inflammation and hysteromyoma. Its main bioactive components are iridoid glycosides, such as 8-O-acetylharpagide and harpagide that had presented antibacterial, anti-inflammatory, and antiviral activities.

AIM OF THE STUDY

To establish a sensitive LC-MS/MS method and compare the pharmacokinetics of 8-O-acetylharpagide and harpagide in rats after oral administration of their pure forms and from compounds obtained from Ajuga decumbens extract.

MATERIALS AND METHODS

Rats received orally 15 mg/kg (equivalent of 6 mg/kg 8-O-acetylharpagide and 1.5mg/kg harpagide), 30 mg/kg and 60 mg/kg of Ajuga decumbens Thunb extract and were compared to animals that received 12 mg/kg of 8-O-acetylharpagide or 3mg/kg of harpagide p.o. Concentrations of 8-O-acetylharpagide and harpagide in plasma were determined by LC-MS/MS method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis.

RESULTS

Results showed that the iridoid glycosides were quickly absorbed by oral route and showed a dose-dependence profile. Pharmacokinetic parameters of both glycosides were essentially the same except Tmax when dosed as the extract or pure forms.

CONCLUSION

8-O-acetylharpagide was metabolized to harpagide, which affected the pharmacokinetic profiles of harpagide when dosed as the extract. This pharmacokinetic study seems to be useful for a further clinical study of Ajuga decumbens Thunb extract.

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.

Beneficial effects of Ajuga decumbens on osteoporosis and arthritis

Extract of the whole plant, Ajuga decumbens (KE) has long been used in China as a medication for the relief of joint pain. Previously, we proved that KE up-regulated the synthesis of collagen in false aged model rats. In this paper we examined the effects of KE on nitric oxide (NO) production, expression of inducible nitric oxide synthase (iNOS), osteoblast and osteoclast activity. We also investigated whether KE had any anti-osteoporosis or anti-arthritic activity by using ovariectmized mice and adjuvant induced arthritic rats. KE exhibited down-regulation of differentiation into osteoclast and up-regulation of mineralization in osteoblast-like MC3T3-E1 cells in a concentration-dependent manner. NO synthesized by iNOS plays important roles in inflammatory disease and imbalance between bone resorption and bone formation caused by estrogen depletion. KE inhibited expression of iNOS which caused concentration dependent inhibition of NO production. Furthermore, KE prevented brittle bones in ovariectomized mice and swelling of the left hind ankle in adjuvant induced arthritic rats. Therefore, KE improved the balance of bone resorption and bone formation, showing anti-inflammatory effects. Consequently, KE is beneficial for sufferers of bone and joint disease.

Abietane diterpenoids from Clerodendrum bungei

Five new naturally occurring abietane diterpenoids (1-5) along with three known diterpenoids (6-8) were isolated from an acetone-soluble extract of the roots of Clerodendrum bungei. The structures of the new compounds were elucidated on the basis of spectroscopic analysis and chemical methods. In addition, all compounds were evaluated for cytotoxic activity against the cultured B16 (murine melanoma), HGC-27 (human gastric), and HEK-293 (human epithelial kidney) cell lines. Uncinatone (7) exhibited moderate cytotoxicity, inhibited cell proliferation, and induced cell-cycle G(2)/M phase arrest.

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.

Neoclerodane Diterpenoids from Ajuga taiwanensis

Phytochemical investigation of Ajuga taiwanensis resulted in the isolation of seven neoclerodane diterpenes, four of which ajugalide-A (1), -B (2), -C (3), and -D (4), are new and the remaining three are known diterpenes, ajugamacrin B (5), ajugapantin A (6), and ajugamarin C1 (7). Their structures were elucidated in spectral and chemical transformation studies.

Vasorelaxant effect of the aqueous extract of Ajuga iva in rat aorta

The aim of the present study was to investigate the ex vivo and in vitro vascular activity of the aqueous extract of Ajuga iva (L.) Schreber (Labiatae) in normotensive Wistar rats. Chronic oral administration of the extract of Ajuga iva did not significantly affect the systolic blood pressure. In aorta isolated from Ajuga iva-treated rats, the contractile response to noradrenaline was depressed compared to the responses obtained in aorta from untreated rats but the endothelium-dependent relaxation evoked by acetylcholine was not affected. In vitro, Ajuga iva extract inhibited the contraction evoked by noradrenaline. The addition of Ajuga iva extract during the plateau phase of noradrenaline-evoked contraction produced a relaxation that was sensitive to N-nitro-L-arginine. After pre-incubation of the artery in the presence of the plant extract, vasorelaxant effect was markedly less pronounced. The endothelium-dependent relaxation induced by acetylcholine was concentration-dependently blunted in the presence of Ajuga iva extract in the bathing solution. This study indicates that the aqueous extract of Ajuga iva possesses NO-mediated and NO-independent vasorelaxing properties in vitro while only the endothelium-independent effect was observed ex vivo.

Acute and chronic toxicological studies of Ajuga iva in experimental animals

Ajuga iva (L.) Schreber (AI), is widely used in the Moroccan pharmacopoeia as a panacea (cure-all), and specifically for gastrointestinal disorders and diabetes, and as an anthelmintic. No toxicological investigations have been carried out on this plant. We have previously observed that single oral doses (2-14 g/kg) of a lyophilised aqueous extract of AI (AI-extract) in mice or daily oral administration of 10 mg/kg of AI-extract in rats for 2 weeks did not result in any adverse effects. We have now evaluated AI-extract for its behavioural and pharmaco-toxicological effects after acute and chronic administration by the oral and intraperitoneal routes in rats and mice. No toxicity was observed in mice after single oral doses of as high as 14 g/kg of the AI-extract. However, single intraperitoneal injections of the AI-extract (1500-5500 mg/kg BW) produced a dose-dependent increase in adverse effects in the general behaviour and the mortality rate; the LD50 of acute intraperitoneal dose was 3.6 g/kg. In chronic toxicological studies in rats, the AI-extract (administered orally at daily doses of 100, 300 and 600 mg/kg for 3 months), did not cause any changes in haematological and biochemical parameters, with the exception of a transient rise in platelet counts and a short-term decrease in serum glucose levels. Histopathological examination of the brain, liver and the kidneys at the end of the study (3 months) showed normal architecture suggesting no morphological disturbances.

Cancer chemopreventive activity of an iridoid glycoside, 8-acetylharpagide, from Ajuga decumbens

In the course of our continuing search for novel cancer chemopreventive agents from natural sources, several kinds of Labiatae plants were screened. Consequently, the iridoid glycoside derivative, 8-acetylharpagide (8-AcHarp), was obtained from the flowering whole plant of Ajuga decumbens as an active constituent. This glycoside exhibited the remarkable inhibitory effect on two-stage carcinogenesis test of mouse skin tumors induced by nitric oxide (NO) donor, (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexen eamide (NOR 1) as an initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter. Further, 8-AcHarp exhibited potent anti-tumor-promoting activity on two-stage carcinogenesis test of mouse hepatic tumor using N-nitrosodiethylamine (DEN) as an initiator and phenobarbital (PB) as a promoter.

Cancer chemopreventive agents (antitumor-promoters) from Ajuga decumbens

Sixteen compounds (1-16) isolated from the flowering whole plant of Ajuga decumbens have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) induction by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), as a primary screening test for antitumor-promoters (potential cancer chemopreventive agents). Five compounds (6, 9, and 12-14) showed strong inhibitory effects on EBV-EA induction. Of these active compounds, two major constituents of this plant, cyasterone (6) and 8-acetylharpagide (13), showed potent antitumor-promoting activities on a mouse-skin in vivo two-stage carcinogenesis procedure, using 7, 12-dimethylbenz[a]anthracene as initiator and TPA as promoter. Further, compound 13 also exhibited potent chemopreventive activity in a mouse pulmonary tumor model.