Effects of Inula Britannica on the production of antibodies and cytokines and on T cell differentiation in C57BL/6 mice immunized by ovalbumin

Phytochemical constituents of Inula britannica as potential inhibitors of dihydrofolate reductase: A strategic approach against shigellosis

Shigella dysenteriae type 1 is considered as an epidemic in different developing countries, which is responsible for the most severe form of bacterial dysentery. It habitually can develop to the most severe form of dysentery with deadly complications. Development of drugs against this disease is still ongoing. Therefore, we used in silico studies to screen the Inula britannica phytocompounds that are used in traditional Chinese and Kampo Medicines and have activities against different diseases. Spinacetin, eupatin, chrysoeriol and diosmetin were successfully passed through the docking-based screening and absorption, distribution, metabolism, excretion and toxicity (ADMET) filtration. The estimated docking affinities of eupatin, diosmetin, chrysoeriol and spinacetin with Dihydrofolate reductase type 1 (DHFR-1), were -6.5, -6.5, -6.3 and -6.1 kcal/mol, respectively. Which were selected for further investigations based on their favorable ADME/Tox characteristics. Then, the 100 ns molecular dynamics (MD) simulations of apo DHFR, spinacetin-DHFR, eupatin-DHFR, chrysoeriol-DHFR and diosmetin-DHFR complexes were carried out. The RMSD fluctuations of the spinacetin, eupatin, chrysoeriol and diosmetin inside the binding site were explored. Subsequently, the effect of binding Spinacetin, eupatin, chrysoeriol and diosmetin upon the dynamic stability of protein was assessed. Additionally, Principal Component Analysis (PCA) and Hydrogen bond analysis was performed for the apo protein and the protein ligand complexes. The results revealed that chrysoeriol and eupatin has good inhibitory effects against DHFR-1 as treatment for Shigella dysenteriae type when compared to other compounds under study. Hence this study implies that eupatin and chrysoeriol are a significantly potential drug like molecule for the treatment of Shigellosis and must undergo validation through in vivo and in vitro experiments.Communicated by Ramaswamy H. Sarma.

Inula britannica fermented with probiotic Weissella cibaria D30 exhibited anti-inflammatory effect and increased viability in RAW 264.7 cells

The objective of this study was to increase the bioavailability of Inula britannica (IB) through fermentation with probiotic Weissella cibaria D30, and to evaluate the chemical composition, viability, and anti-inflammatory effect of fermented I. britannica (FIB). IB was fermented with W. cibaria D30 at 37 °C for 24 h. FIB increased total phenolic content and decreased total flavonoid content of IB. 1-O-acetylbritannilactone and ergolide production, which are associated with the viability, increased from 1.38 to 4.13 μg/mg, and decreased from 5.24 to 0.94 μg/mg, in the control and FIB, respectively. In addition, the cell viability of RAW264.7 cells increased when pretreated with 400 μg/mL FIB. FIB inhibited the production of nitric oxide and proinflammatory cytokines by inhibiting NF-κB and MAPKs pathways. Therefore, FIB with W. cibaria D30 reduced the toxicity and increased the anti-inflammatory properties. These results indicate that FIB is a potential beneficial bioactive agent for functional foods.

Antiaging Effect of Inula britannica on Aging Mouse Model Induced by D-Galactose

The antiaging effect of Inula britannica flower total flavonoids (IBFTF) on aging mice induced by D-galactose and its mechanism was examined in this study. From the results, the biochemical indexes and histological analysis of skin tissues showed that IBFTF could effectively improve the antioxidant enzyme activity of the aging mice, enhance the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) of skin tissue, and decrease the malondialdehyde (MDA) content. Besides, IBFTF could maintain the skin collagen, hydroxyproline (Hyp), dermal thickness, and moisture content. Meanwhile, IBFTF could significantly reduce the number of cells arrested in G0/G1 phase, and from the point of view of protein and mRNA expression level in skin tissue, IBFTF could significantly increase the expression of Sirt1 and CyclinD1 but decrease the expression of p16 and p21, and its effect was not less than that of the well-known vitamin E (VE). Overall, these results seem to be implying that IBFTF is a potential natural anti-skin aging agent with great antioxidant ability.

LC-MS/MS determination of 1-O-acetylbritannilactone in rat plasma and its application to a preclinical pharmacokinetic study

A novel, rapid and sensitive LC-MS/MS method for the determination of 1-O-Acetylbritannilactone (ABL), a sesquiterpene lactone abundant in Inula britannica, was developed and validated using heteroclitin D as internal standard. Separation was achieved on a reversed phase Hypersil Gold C18 column (50 × 4.6 mm, i.d., 3.0 µm) using isocratic elution with methanol-5 mM ammonium acetate buffer aqueous solution (80:20, v/v) at a flow rate of 0.4 mL/min. Calibration curve was linear (r > 0.99) in a concentration range of 1.60-800 ng/mL with the lower limit of quantification of 1.60 ng/mL. Intra- and inter-day accuracy and precision were validated by relative error (RE) and relative standard deviation (RSD) values, respectively, which were both less than ±15%. The validated method has been successfully applied to a pharmacokinetic study of ABL in rats. The elimination half-lives were 0.412 ± 0.068, 0.415 ± 0.092 and 0.453 ± 0.071 h after a single intravenous administration of 0.14, 0.42, and 1.26 mg/kg ABL, respectively. The area under the plasma concentration-time curve from time zero to the last quantifiable time point and from time zero to infinity and the plasma concentrations at 2 min were linearly related to the doses tested.

The genus Inula and their metabolites: from ethnopharmacological to medicinal uses

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Inula comprises more than one hundred species widespread in temperate regions of Europe and Asia. Uses of this genus as herbal medicines have been first recorded by the Greek and Roman ancient physicians. In the Chinese Pharmacopoeia, from the 20 Inula spp. distributed in China, three are used as Traditional Chinese medicines, named Tumuxiang, Xuanfuhua and Jinfeicao. These medicines are used as expectorants, antitussives, diaphoretics, antiemetics, and bactericides. Moreover, Inula helenium L. which is mentioned in Minoan, Mycenaean, Egyptian/Assyrian pharmacotherapy and Chilandar Medical Codex, is good to treat neoplasm, wound, freckles and dandruff. Many other Inula spp. are used in Ayurvedic and Tibetan traditional medicinal systems for the treatment of diseases such as bronchitis, diabetes, fever, hypertension and several types of inflammation. This review is a critical evaluation of the published data on the more relevant ethnopharmacological and medicinal uses of Inula spp. and on their metabolites biological activities. This study allows the identification of the ethnopharmacological knowledge of this genus and will provide insight into the emerging pharmacological applications of Inula spp. facilitating the prioritirization of future investigations. The corroboration of the ethnopharmacological applications described in the literature with proved biological activities of Inula spp. secondary metabolites will also be explored.

MATERIALS AND METHODS

The major scientific databases including ScienceDirect, Medline, Scopus and Web of Science were queried for information on the genus Inula using various keyword combinations, more than 180 papers and patents related to the genus Inula were consulted. The International Plant Name Index was also used to confirm the species names.

RESULTS

Although the benefits of Inula spp. are known for centuries, there are insufficient scientific studies to certify it. Most of the patents are registered by Chinese researchers, proving the traditional use of these plants in their country. Although a total of sixteen Inula species were reported in the literature to have ethnopharmacological applications, the species Inula cappa (Buch.-Ham. ex D.Don) DC., Inula racemosa Hook.f., Inula viscosa (L.) Aiton [actually the accepted name is Dittrichia viscosa (L.) Greuter], Inula helenium, Inula britannica L. and Inula japonica Thunb. are the most frequently cited ones since their ethnopharmacological applications are vast. They are used to treat a large spectrum of disorders, mainly respiratory, digestive, inflammatory, dermatological, cancer and microbial diseases. Fifteen Inula spp. crude extracts were investigated and showed interesting biological activities. From these, only 7 involved extracts of the reported spp. used in traditional medicine and 6 of these were studied to isolate the bioactive compounds. Furthermore, 90 bioactive compounds were isolated from 16 Inula spp. The characteristic compounds of the genus, sesquiterpene lactones, are involved in a network of biological effects, and in consequence, the majority of the experimental studies are focused on these products, especially on their cytotoxic and anti-inflammatory activities. The review shows the chemical composition of the genus Inula and presents the pharmacological effects proved by in vitro and in vivo experiments, namely the cytotoxic, anti-inflammatory (with focus on nitric oxide, arachidonic acid and NF-κB pathways), antimicrobial, antidiabetic and insecticidal activities.

CONCLUSIONS

Although there are ca. 100 species in the genus Inula, only a few species have been investigated so far. Eight of the sixteen Inula spp. with ethnopharmacological application had been subjected to biological evaluations and/or phytochemical studies. Despite Inula royleana DC. and Inula obtusifolia A. Kerner are being used in traditional medicine, as far as we are aware, these species were not subjected to phytochemical or pharmacological studies. The biological activities exhibited by the compounds isolated from Inula spp., mainly anti-inflammatory and cytotoxic, support some of the described ethnopharmacological applications. Sesquiterpene lactone derivatives were identified as the most studied class, being britannilactone derivatives the most active ones and present high potential as anti-inflammatory drugs, although, their pharmacological effects, dose-response relationship and toxicological investigations to assess potential for acute or chronic adverse effects should be further investigated. The experimental results are promising, but the precise mechanism of action, the compound or extract toxicity, and the dose to be administrated for an optimal effect need to be investigated. Also human trials (some preclinical studies proved to be remarkable) should be further investigated. The genus Inula comprises species useful not only in medicine but also in other domains which makes it a high value-added plant.

Hepatoprotective effect of the flavonoid fraction isolated from the flower of Inula britannica against D-Galactosamine-induced hepatic injury

The aim of this study was to investigate the mechanism and nature of the protective effect of Inula britannica flower flavonoids (IBFF) on antioxidants and the inhibition of inflammation in liver injury. Liver injury was induced in a mouse model by intraperitoneal injection of D-Galactosamine (D-Gal; 850 mg/kg) and IBFF was administered orally at 125, 250 or 500 mg/kg once a day for 7 days. The results revealed that IBFF reversed the increases in serum aminotransferase levels and lipid peroxidation and also reversed the decreases in hepatic glutathione content. IBFF attenuated the D-Gal-induced increases in tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA and protein levels in the liver. Our data suggest that IBFF ameliorates D-Gal-induced acute liver injury and that this protection may be due to its antioxidative and anti-inflammatory activities.

Inulae Flos and Its Compounds Inhibit TNF-α- and IFN-γ-Induced Chemokine Production in HaCaT Human Keratinocytes

The present study is to investigate which kinds of solvent extracts of Inulae Flos inhibit the chemokine productions in HaCaT cell and whether the inhibitory capacity of Inulae Flos is related with constitutional compounds. The 70% methanol extract showed comparatively higher inhibition of thymus and activation-regulated chemokine (TARC/CCL17) in HaCaT cells, therefore this extract was further partitioned with n-hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction inhibited TARC, macrophage-derived chemokine (MDC/CCL22), and regulated on activation of normal T-cell-expressed and -secreted (RANTES/CCL5) production in HaCaT cells better than the other fractions. The compounds of Inulae Flos, such as 1,5-dicaffeoylquinic acid and luteolin, inhibited TARC, MDC, and RANTES production in HaCaT cells. 1,5-Dicaffeoylquinic acid was contained at the highest concentrations both in the 70% methanol extract and ethyl acetate fraction and inhibited the secretion of chemokines dose-dependently more than the other compounds. Luteolin also represented dose-dependent inhibition on chemokine productions although it was contained at lower levels in 70% methanol extract and solvent fractions. These results suggest that the inhibitory effects of Inulae Flos on chemokine production in HaCaT cell could be related with constituent compounds contained, especially 1,5-dicaffeoylquinic acid and luteolin.

Secondary metabolites from Inula britannica L. and their biological activities

Inula britannica L., family Asteraceae, is used in traditional Chinese and Kampo Medicines for various diseases. Flowers or the aerial parts are a rich source of secondary metabolites. These consist mainly of terpenoids (sesquiterpene lactones and dimmers, diterpenes and triterpenoids) and flavonoids. The isolated compounds have shown diverse biological activities: anticancer, antioxidant, anti-inflammatory, neuroprotective and hepatoprotective activities. This review provides information on isolated bioactive phytochemicals and pharmacological potentials of I. britannica.

Acetylbritannilactone Inhibits Neointimal Hyperplasia after Balloon Injury of Rat Artery by Suppressing Nuclear Factor-{kappa}B Activation

Based on our previous observations that 1-O-acetylbritannilactone (R)-4((3aS,4S,7aR)-4-hydroxy-6-methyl-3-methylene-2-oxo-2,3,3a,4,7,7a-hexahydrobenzofuran-5-yl)pentyl acetate (ABL) suppresses prostaglandin E(2) and nitric oxide synthesis in macrophages, the present study was designed to explore the effect of ABL on neointimal hyperplasia after balloon injury and its mechanism of action. In male Sprague-Dawley rats, 26 mg/kg ABL or polyglycol (control) was administered daily from 3 days before injury to 2 weeks after conventional balloon injury. ABL administration led to a significant reduction in neointimal formation (neointima to media ratio, 1.94 +/- 0.43 versus 0.84 +/- 0.29, P < 0.01) and proliferative activity of vascular smooth muscle cells after balloon injury in rats. Western blot analysis revealed that this is correlated to the inhibition of nuclear factor (NF)-kappaB activation and to the reduced expression of cyclooxygenase-2. Investigation of potential signaling pathways demonstrated that ABL inhibited NF-kappaB activation via the blockade of the inhibitor of NF-kappaB kinase-beta activation and the suppression of the degradation of the inhibitors of NF-kappaB-alpha. These findings suggest that ABL is a potential inhibitor of neointimal formation because it blocks injury-induced NF-kappaB activation and may have beneficial effects in reducing the risk of restenosis after angioplasty.

Anti-diabetic and Hypolipidemic Effects of Aqueous-Extract from the Flower of Inula japonica in Alloxan-Induced Diabetic Mice

The anti-diabetic and hypolipidemic effects of aqueous-extract from the flower of Inula japonica (IJ) and its two fractions (IJR and IJP) were investigated in alloxan-induced diabetic mice. An oral glucose tolerance test (OGTT) of IJ was also performed in normal and diabetic mice. The results showed that IJ (1000 mg/kg), IJR (500 mg/kg) and IJP (250 mg/kg) significantly reduced blood glucose levels in diabetic mice by oral administration (p<0.01). IJ and IJP markedly decreased serum triglyceride concentrations (p<0.05) in diabetic mice. Their hypoglycemic activities were better than gliclazide (40 mg/kg) and compared with metformin (250 mg/kg). IJ raised plasma insulin levels in alloxan-induced diabetic mice. IJ, IJR and IJP significantly decreased the consumption of water and food in diabetic mice. OGTT showed that IJ slightly lowered blood glucose levels in normal mice, but significantly decreased blood glucose in diabetic mice between 60-150 min after a glucose load (p<0.05). The data indicated that IJ has both anti-diabetic and hypolipidemic effects.