Two new flavonol glycosides from the leaves of Elaeagnus pungens

Characterization of chloroplast genome and phylogenetic analysis of the Elaeagnus hybrid variety E. 'viridis' (Elaeagnaceae)

Elaeagnus 'viridis', an artificial hybrid of E. macrophylla (♂) Thunb. (1784) × E. pungens (♀) Thunb. (1784), is known for its economic and ecological value. In this study, we sequenced and assembled the whole chloroplast (cp) genome of E. 'viridis'. The results showed that its cp genome was 152,284 bp long, showing a typical quadripartite structure and containing a large single-copy region (LSC, 82,299 bp), a small single-copy region (SSC, 18,239 bp), and a pair of inverted repeats (IRs, 51,746 bp). The cp genome contains 132 genes, including 86 protein-coding genes (PCGs), 38 tRNA genes, and 8 rRNA genes. Phylogenetic analysis based on 66 common PCGs revealed that E. 'viridis' is most closely related to its maternal parent E. pungens. The chloroplast genomic information reported in this study will shed some useful light for further genetic studies in the genus Elaeagnus.

In vitro and in vivo relaxation and anti-inflammation of natural flavonoids from Elaeagnus pungens leaf via L-type calcium channel and targeting MAPK signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicine (TCM), the leaf of Elaeagnus pungens Thunb. (Family Elaeagnaceae) is a herb documented as an antiasthmatic remedy to treat the severe asthma, bronchitis and other respiratory diseases in the early material medica "Bencao Gangmu" (Ming dynasty, about 442 years ago).

AIM OF THE STUDY

This work is purposed to investigate the pharmacological effects and mechanism of total flavonoids from Elaeagnus pungens leaves (FLA) on asthma in vivo and vitro.

MATERIALS AND METHODS

Female BALB/c mice were sensitized by intraperitoneal injection of OVA with aluminum hydroxide and intranasal challenged with OVA. After treatment with FLA (10, 20 mg/kg p.o.), the behaviors of mice were observed by score evaluation. Enumeration of total cells and OVA-specific IgE assay in the blood were measured as well as enumeration of total cells and cytokines assay in the BALF. Furthermore, histopathological analysis was performed by HE staining. The in vitro relaxing action on muscle force of FLA (0.0316-10.0 mg/ml) was evaluated using isometric tension in tracheal rings, and VDLCC currents were recorded to explore the relaxation mechanism in the isolated tracheal rings and mouse ASM cells, respectively. In vitro anti-inflammatory actions were assessed with LPS-stimulated RAW 264.7 macrophages. The production of inflammatory mediators and MAPK signaling pathway was estimated using ELISA and Western blotting analysis, respectively.

RESULTS

The high dose of flavones from E. pungens leaf (20 mg/kg) can significantly improve the symptom of asthma breakout and relieve the lung swelling. FLA treatment decreased eosinophils and leukocytes numbers in blood and BLAF with a dosedependent manner. Furthermore, the inhibiting effect of FLA on the level of Ig E and inflammatory-related cytokines including TNF-α, IL-5 showed dose-independent. FLA relaxed high K + -induced contraction in a dose-dependent manner. The maximal relaxation produced by FLA was 99.7% (IC 50 = 0.46 mg/ml). The whole-cell VDLCC currents were abolished by FLA (3.16 mg/ml) and FLA significantly decreased the maximal amplitude of VDLCCs. No cytotoxic effect of FLA was observed in RAW264.7 cells under the tested concentrations (1-300 μg/mL). The increased IL-6 and NO by the stimulation of LPS in RAW264.7 cells were significantly inhibited by FLA in the dosedependent manner. Treatment with LPS in the presence of FLA, LPS-induced phosphorylation of ERK1/2 and JNK was inhibited in the macrophages.

CONCLUSION

FLA from Elaeagnus pungens leaf can alleviate the inflammation symptom via reducing the eosinophils and leukocytes numbers as well as the production of pro-inflammatory cytokines. This anti-inflammatory effect is related to the modulation of the MAPK signaling pathway. FLA can relax the precontracted TRs by blocking the VDLCCs, which interrupts extracellular Ca 2+ influx and inhibit the rise of [Ca 2+ ]i. It strongly suggests that these flavonoids components are the substances basis of Elaeagnus pungens leaves for allergic action, bronchospasm and inflammation in asthma.

Unusual isovalerylated flavonoids from the fruit of sea buckthorn (Elaeagnus rhamnoides) grown in Sokółka, Poland

Eight undescribed isorhamnetin glycosides, acylated with isovaleric acid were isolated from the fruit of sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson). Structures of the purified compounds were determined using one and two-dimensional NMR spectroscopy, mass spectrometry and chemical methods. In addition, the cytotoxic activity of the phenolic-rich fraction of sea buckthorn fruit and its major flavonoids against colon cell lines, HT-29, HCT-116 and Caco-2, was determined. While the phenolic fraction was moderately active against HT-29 and HCT-116, all investigated purified flavonoids showed significantly weaker activity. This is most probably the first report about isorhamnetin glycosides acylated with isovaleric acid.

Quercetin, Kaempferol and Isorhamnetin in Elaeagnus pungens Thunb. Leaf: Pharmacological Activities and Quantitative Determination Studies

Elaeagnus pungens leaf was documented to be very effective to treat asthma and chronic bronchitis both as traditional Chinese medicine and minority traditional medicine; yet the actual effective components still remain unknown. This work is to investigate the anti-inflammatory, antalgic and antitussive activities of E. pungens leaf, quercetin and kaempferol, and their contents in E. pungens leaf. Pharmacological experiments showed that they could considerably reduce ear-swelling of mouse and relieve writhing reaction of mouse; they could also prevent mouse from coughing significantly. These findings suggested that quercetin and kaempferol are major effective components treating asthma and chronic bronchitis. Quantitative analysis results indicated that the levels of quercetin, kaempferol and isorhamnetin varied greatly in different species of Elaeagnus and in different plant parts: E. pungens leaf is more similar to Elaeagnus umbellate leaf chemically; quercetin level is exceptionally high in Elaeagnus oldhami leaf; E. pungens leaf is a better medical part for treating asthma and chronic bronchitis in comparison with other parts.

Emodinol ameliorates urate nephropathy by regulating renal organic ion transporters and inhibiting immune inflammatory responses in rats

Emodinol, 1β, 3β, 23-trihydroxyolean-12-en-28-acid, as the main active ingredient firstly extracted from the rhizomes of Elaeagus pungens by our Research Group, was identified with apparent uricosuric and nephroprotective effects in hyperuricemia mice in our previous study. This study aimed to investigate the renal protective effect of emodinol in urate nephropathy rats. Rats were orally administrated by combined adenine and ethambutol to induce urate nephropathy. Emodinol at various doses were administered intragastrically to urate nephropathy rats daily. Serum uric acid (Sur), serum creatinine (Scr) and blood urea nitrogen (BUN) levels, as well as Interleukin-1beta (IL-1β) and tumor necrosis factor- alpha (TNF-α) concentrations in serum and kidney were determined. Renal protein expressions of organic ion transporters, components of NLR pyrin domain containing 3 (NLRP3) inflammasome, as well as key factors involved in toll-like receptors (TLRs)/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) signaling pathway were analyzed by western blot. Emodinol significantly decreased Sur, Scr and BUN levels in adenine and ethambutol - induced urate nephropathy rats. More importantly, emodinol reversed dys-expression of organic ion transporters, inhibited NLRP3 inflammsome activation and suppressed TLRs/MyD88/NF-κB signaling pathway in the kidneys of urate nephropathy rats. Consistently, dilated tubules and tubular UA crystal formation, as well as tubular interstitial inflammatory cells infiltration in kidneys of urate nephropathy rats were obviously attenuated by emodinol, accompanied by restored renal and serum inflammatory cytokines concentrations. Taken together, the date suggested that emodinol ameliorated urate nephropathy by regulating renal organic ion transporters and inhibiting immune inflammatory responses in rats.

Flavonoid Accumulation Plays an Important Role in the Rust Resistance of Malus Plant Leaves

Cedar-apple rust (Gymnosporangium yamadai Miyabe) is a fungal disease that causes substantial injury to apple trees and results in fruit with reduced size and quality and a lower commercial value. The molecular mechanisms underlying the primary and secondary metabolic effects of rust spots on the leaves of Malus apple cultivars are poorly understood. Using HPLC, we found that the contents of flavonoid compounds, especially anthocyanin and catechin, were significantly increased in rust-infected symptomatic tissue (RIT). The expression levels of structural genes and MYB transcription factors related to flavonoid biosynthesis were one- to seven-fold higher in the RIT. Among these genes, CHS, DFR, ANS, FLS and MYB10 showed more than a 10-fold increase, suggesting that these genes were expressed at significantly higher levels in the RIT. Hormone concentration assays showed that the levels of abscisic acid (ABA), ethylene (ETH), jasmonate (JA) and salicylic acid (SA) were higher in the RIT and were consistent with the expression levels of McNCED, McACS, McLOX and McNPR1, respectively. Our study explored the complicated crosstalk of the signal transduction pathways of ABA, ETH, JA and SA; the primary metabolism of glucose, sucrose, fructose and sorbitol; and the secondary metabolism of flavonoids involved in the rust resistance of Malus crabapple leaves.

In Vivo Evaluation of the Antiasthmatic, Antitussive, and Expectorant Activities and Chemical Components of Three Elaeagnus Leaves

The leaf of Elaeagnus lanceolata and Elaeagnus henryi as well as Elaeagnus pungens has been documented as an effective herb for the treatment of asthma and chronic bronchitis in traditional clinical medicine. This study was aimed at evaluating the antiasthmatic, antitussive, and expectorant activities of the water extracts from the three plants in vivo and analyzing their chemical components by HPLC-DAD. At the medium and high doses, the water extracts of three Elaeagnus leaves significantly prolonged the preconvulsive time (P < 0.01) in guinea pigs, lengthened the latent period of cough (P < 0.01) and decreased the cough frequency caused by aqueous ammonia in mice (P < 0.01), and enhanced tracheal phenol red output in mice (P < 0.01). There were no significant differences in the pharmacological actions between the three Elaeagnus leaves. Moreover, there was more similarity on overlap peaks in the range of retention time from 10 to 40 min by HPLC and many peaks that belonged to flavonoids compounds. It suggested that the main constituents of the three Elaeagnus leaves were flavonoid for the pharmacological activities. These effects were the important evidence for the traditional use of E. henryi leaf and E. lanceolata leaf as well as E. pungens to treat asthma and chronic bronchitis.

Studies on cytotoxic constituents from the leaves of Elaeagnus oldhamii Maxim. in non-small cell lung cancer A549 cells

Elaeagnus oldhamii Maxim. is a commonly used traditional herbal medicine. In Taiwan the leaves of E. oldhamii Maxim. are mainly used for treating lung disorders. Twenty five compounds were isolated from the leaves of E. oldhamii Maxim. in the present study. These included oleanolic acid (1), 3-O-(Z)-coumaroyl oleanolic acid (2), 3-O-(E)-coumaroyl oleanolic acid (3), 3-O-caffeoyl oleanolic acid (4), ursolic acid (5), 3-O-(Z)-coumaroyl ursolic acid (6), 3-O-(E)-coumaroyl ursolic acid (7), 3-O-caffeoyl ursolic acid (8), 3β, 13β-dihydroxyolean-11-en-28-oic acid (9), 3β, 13β-dihydroxyurs-11-en-28-oic acid (10), uvaol (11), betulin (12), lupeol (13), kaempferol (14), aromadendrin (15), epigallocatechin (16), cis-tiliroside (17), trans-tiliroside (18), isoamericanol B (19), trans-p-coumaric acid (20), protocatechuic acid (21), salicylic acid (22), trans-ferulic acid (23), syringic acid (24) and 3-O-methylgallic acid (25). Of the 25 isolated compounds, 21 compounds were identified for the first time in E. oldhamii Maxim. These included compounds 1, 4, 5 and 8–25. These 25 compounds were evaluated for their inhibitory activity against the growth of non-small cell lung cancer A549 cells by the MTT assay, and the corresponding structure-activity relationships were discussed. Among these 25 compounds, compound 6 displayed the best activity against the A549 cell line in vitro (CC₅₀ = 8.56 ± 0.57 μg/mL, at 48 h of MTT asssay). Furthermore, compound 2, 4, 8 and 18 exhibited in vitro cytotoxicity against the A549 cell line with the CC₅₀ values of less than 20 μg/mL at 48 h of MTT asssay. These five compounds 2, 4, 6, 8 and 18 exhibited better cytotoxic activity compared with cisplatin (positive control, CC₅₀ value of 14.87 ± 1.94 μg/mL, at 48 h of MTT asssay). The result suggested that the five compounds might be responsible for its clinical anti-lung cancer effect.

Relaxant effect of 1-butanol fraction from Elaeagnus pungens leaf through inhibiting L-type Ca2+ channel on guinea pig tracheal smooth muscle

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf of Elaeagnus pungens thunb. (Family Elaeagnaceae) has been documented as an effective herb for the treatment of asthma and chronic bronchitis in traditional Chinese medicine. In the past years, only a few of preliminary studies reported the chemical constituents and pharmacology effects of the herb, but their action on the tracheal relaxation has not been investigated.

AIM OF THE STUDY

To investigate the relaxing effect and mechanism of the extracts from Elaeagnus pungens leaves on guinea pig tracheal smooth muscle and bronchi smooth muscle cells.

MATERIALS AND METHODS

Four fractions of different polarities from Elaeagnus pungens leaves were tested to the tracheal strips on the resting tension or pre-contracted by histamine (20 μM) and acetylcholine (20 μM). Inhibitory effects of the 1-butanol fraction (400mg/ml) on cumulative histamine and acetylcholine (0.2-20 μM) induced contraction were measured. In order to determine the mediators on the 1-butanol fraction effect, the relaxing effect of the 1-butanol fraction was evaluated in the absence and presence of β-adrenoceptor antagonists (1 μM propranolol), K(+) channels-blockers (4-aminopyridine (2mM), tetraethylammonium chloride (5mM) or glibenclamide (10 μM)), the cyclooxygenase inhibitor (indomethacin, 10 μM), nitric oxide synthase inhibitor (Nω-nitro-L-arginine methyl ester, 100 μM) or L-type Ca(2+) channel inhibitor (nifedipine, 1 μM). Moreover, [Ca(2+)]i in bronchi smooth muscle cells was analyzed by measuring the fluorescence intensity with confocal system.

RESULTS

1-Butanol fraction induced the highest relaxant effect among four fractions of different polarities from Elaeagnus pungens leaves, and significantly relaxed the tracheal strip in the concentration-dependent manner on the resting tension and pre-contracted by histamine phosphate and acetylcholine. It also produced an unparallel rightward shift of the cumulative concentration-response curve of histamine or acetylcholine. Furthermore, the relaxant effect of 1-butanol fraction was not affected by propranolol, glibenclamide, tetraethylammonium chloride, 4-aminopyridine, indomethacin and Nω-nitro-L-arginine methyl ester. However, 1-butanol fraction-induced relaxation decreased after adding nifedipine. It also concentration-dependently inhibited CaCl2-induced contraction in the Ca(2+)-free, 60mM K(+)-containing solution. Additionally, [Ca(2+)]i in the BSMCs significantly reduced after administration of the 1-butanol fraction.

CONCLUSIONS

The 1-butanol fraction from Elaeagnus pungens leaves resulted in a relaxation in the non-precontracted and pre-contracted tracheal strips. The relaxant effect was not related to K(+) channels, NO, cGMP or β-adrenoceptors, but related to the inhibition of Ca(2+) influx through L-type Ca(2+) channels.

One lignanoid compound and four triterpenoid compounds with anti-inflammatory activity from the leaves of Elaeagnus oldhamii maxim

One lignanoid compound, isoamericanol B (1), along with four triterpenoid compounds-cis-3-O-p-hydroxycinnamoyloleanolic acid (2), trans-3-O-p-hydroxy cinnamoyloleanolic acid (3), cis-3-O-p-hydroxycinnamoylursolic acid (4), trans-3-O-p-hydroxycinnamoylursolic acid (5) have been isolated for the first time from the leaves of Elaeagnus oldhamii Maxim. Compounds 1-4 significantly inhibited the expression of NO (nitric oxide) produced in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The IC50 value for inhibition of nitrite production of compound 1 was about 10.3 ± 0.4 μg/mL. In the cell viability test, however, among compounds 1-4 compound 1 did not significantly change cell viability. Therefore, in this study compound 1 possessed anti-inflammatory effects. The result suggests compound 1 as a potential lead compound for the treatment of inflammatory diseases.