Isolation and antibacterial activity of phenylpropanoid derivatives from Ballota nigra

In addition to the previously isolated phenylpropanoid glycosides verbascoside 1, forsythoside B 2, arenarioside 3 and ballotetroside 4, another four compounds were isolated from generative aerial parts of Ballota nigra: three phenylpropanoid glycosides, alyssonoside 5, lavandulifolioside 6 and angoroside A 7 and a non-glycosidic derivative (+)-(E)-caffeoyl-L-malic acid 8. The antibacterial activity of the five major compounds (1-4 and 8) was tested against gram-positive and gram-negative bacteria. Three of them (1-3) exhibited a moderate antimicrobial activity against Proteus mirabilis and Staphylococcus aureus including one methicillin-resistant strain.     

Phytochemical investigation and antioxidant activity of Duranta repens

The ethylacetate fraction of the methanol extract of Duranta repens L. (Verbenaceae) showed radicalscavenging activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Three compounds were isolated from this fraction, i.e. the phenylethanoid glycoside acteoside, the iridoid lamiide and the saponin pseudo-ginsenoside-RT1. Acteoside showed an IC50 of 3.05 +/- 0.09 microg/mL in the DPPH assay, while lamiide and pseudo-ginsenoside-RT1 were not active.     

Endothelium-dependent effects of the ethanolic extract of the mistletoe Psittacanthus calyculatus on the vasomotor responses of rat aortic rings

The mistletoe Psittacanthus calyculatus (Loranthaceae) is used in Mexican traditional medicine for the treatment of hypertension. In the present study the effects of a crude ethanolic extract of this mistletoe, on the vasomotor reactivity of superfused rat aortic rings (with or without a functional endothelium) were analyzed. Either in the absence or in the presence of L-NAME or indomethacin, the extract (12.5-800 microg/ml) had no effect on the basal tone of both types of rings. In phenylephrine-precontracted rings, low concentrations of the extract (up to 300 microg/ml) induced a small additional tension development in both types of rings; however, the tension increase was slightly larger in rings having an intact endothelium. At higher concentrations (400-800 microg/ml), the extract relaxed, concentration-dependently, phenylephrine-precontracted rings with an intact endothelium. This relaxation was completely reverted by the addition of L-NAME. When the extract was applied in the continuous presence of L-NAME to phenylephrine-precontracted rings, instead of a relaxation a marked additional tension development occurred. Indomethacin did not modify the relaxation induced by the extract. The results indicate that the ethanolic extract of this mistletoe induces, predominantly, an endothelium-dependent relaxation which seems to be mediated by the synthesis/release of nitric oxide.     

Nitric oxide-dependent vasorelaxation induced by extractive solutions and fractions of Maytenus ilicifolia Mart ex Reissek (Celastraceae) leaves

This study reveals that an ethanolic supernatant obtained from an aqueous extractive solution prepared from residues of methanolic extracts of ground leaves of Maytenus ilicifolia is able to cause a concentration- and endothelium-dependent relaxation in pre-contract rat aorta rings, with EC(50) of 199.7 (190-210) microg/ml. The non-selective nitric oxide synthase inhibitors l-NAME and l-NMMA abolished this effect, while superoxide dismutase and MnTBAP (a non-enzymatic superoxide dismutase mimetic) enhanced it. Further, relaxation induced by this ethanolic supernatant have been strongly inhibited by the guanylate cyclase inhibitors methylene blue and ODQ, as well as by the potassium channel blockers 4-aminopyridine and tetraethylammonium, but was unchanged by the cyclooxygenase inhibitor indomethacin and the membrane receptor antagonists atropine, HOE-140 and pirilamine. Partition of the ethanolic supernatant between H(2)O and EtOAc generated a fraction several times more potent, able to fully relax endothelium-intact aorta rings with an EC(50) of 4.3 (3.9-4.8) microg/ml. (13)C NMR spectrum of this fraction showed signals typical of catechin. This study reveals that the leaves of M. ilicifolia possess one or more potent substances able to relax endothelium-intact rat aorta rings, an event that appears to involve nitric oxide production, guanylate cyclase activation and potassium channel opening.     

Angiotensin converting enzyme inhibitory phenylpropanoid glycosides from Clerodendron trichotomum

The stems of Clerodendron trichotomum have been traditionally used for treatment of hypertension in far East Asia including China, Korea, and Japan. Bioassay-guided fractionation and purification of the EtOAc-soluble extract of Clerodendron trichotomum afforded acteoside (1), leucosceptoside A (2), martynoside (3), acteoside isomer (4), and isomartynoside (5). The angiotensin converting enzyme (ACE) activities were significantly inhibited by the addition of these phenylpropanoid glycosides (1-5) in a dose-dependent manner of which IC(50) values were 373+/-9.3 microg/ml, 423+/-18.8 microg/ml, 524+/-28.1 microg/ml, 376+/-15.6 microg/ml, 505+/-26.7 microg/ml, respectively. These results suggest that the antihypertensive effect of Clerodendron trichotomum may be, at least in part, due to ACE inhibitory effect of phenylpropanoid glycosides.     

Phenylpropanoids from Ballota nigra L. inhibit in vitro LDL peroxidation

From the European plant Ballota nigra L. various polyphenols including phenylpropanoid derivatives were isolated. There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherogenesis. The goal of this study was to test whether the major polyphenolic compounds extracted from Ballota nigra, four phenylpropanoid glycosides, verbascoside, forsythoside B, arenarioside, and ballotetroside and one non-glycosidic phenylpropanoid, caffeoyl-L-malic acid, inhibit Cu(2+)-induced LDL peroxidation. The effectiveness of these compounds was compared to the activity of quercetin, a well-known polyphenol inhibitor of Cu(2+)-induced LDL oxidation. Antioxidant efficacious doses (ED 50) of arenarioside and ballotetroside were 1.8 microM and 7.5 microM respectively, while in the same conditions, the ED 50 of forsythoside B and verbascoside were similar (1 microM) and those of quercetin and of caffeoyl-L-malic acid were 2.3 microM and 9.5 microM respectively. Spectrophotometric studies show that quercetin is a Cu(2+) chelator while phenylpropanoid glycosides and caffeoyl-L-malic acid are not Cu(2+) chelators. Therefore, phenylpropanoid glycosides are strong inhibitors of Cu(2+)-induced LDL oxidation, independent of any capacity to act as Cu(2+) chelators.     

栀子环烯醚萜苷治疗脑缺血损伤的作用机制研究

目的: 探讨近几年来栀子环烯醚萜苷治疗脑缺血损伤的作用机制,为栀子环烯醚萜苷类成分的进一步研究和应用提供参考。 方法: 查阅国内外相关文献并进行归纳、总结。 结果: 环烯醚萜苷类成分是栀子药材的主要化学成分。研究表明,它不仅有明显的保肝利胆、解热、镇静等作用,而且对缺血性脑损伤亦有保护作用。关于栀子环烯醚萜苷类成分对缺血性脑损伤的保护作用研究较多,其作用机制是多方面的。 结论: 栀子环烯醚萜苷治疗脑缺血损伤的作用机制有待进一步研究。     

玄参的化学成分及质量控制研究进展

参考阅读近几年来国内外与玄参研究相关的文献,对玄参的化学成分及其质量控制方法进行了综述。目前其主要化学成分为环烯醚萜类、苯丙素苷类、芳香糖苷类等;目前主要的质量控制手段有多指标性含量测定及指纹图谱等,为深入研究玄参提供进一步参考。     

Isolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare

The isolation and identification of major phenylpropanoid esters from Marrubium vulgare: (+) (E)-caffeoyl-L-malic acid 1, acteoside 2, forsythoside B 3, arenarioside 4, ballotetroside 5, as well as their anti-inflammatory activity are reported for the first time. We evaluated the inhibitory effects of these five compounds on cyclooxygenase (Cox) catalysed prostaglandin biosynthesis activity. Only the glycosidic phenylpropanoid esters showed an inhibitory activity towards the Cox-2 enzyme and three of them: acteoside 2, forsythoside B 3, arenarioside 4, exhibited higher inhibitory potencies on Cox-2 than on Cox-1. These results are of interest, as Cox-2 is mainly associated with inflammation and the Cox-1 inhibition with adverse side effects often observed with non-steroidal anti-inflammatory drugs. The occurrence of these phenylpropanoid esters could also explain some other pharmacological properties of M. vulgare.     

In vitro purgative effect of Ruellia praetermissa. Sceinf.ex.Lindau (Acanthaceae)

Methanol, ethylacetate and aqueous extracts of Ruellia praetermissa initiated spontaneous contractions in the quiescent and increased contraction on the electrically stimulated ileal strip at a concentration of 30 microg/ml. The extracts produced concentration-related contractions both in amplitude and tone up till 750 microg/ml with IC(50) of 360 microg/ml (methanol extract), 425 microg/ml (ethylacetate extract) and 540 microg/ml (aqueous extract). Acetylcholine also produced a concentration-related (IC(50)=18 microg/ml) contractions of the isolated ileum. Atropine in concentrations of 3.4 x 10(-6)-3 x 10(-3) microg/ml antagonized progressively the response of the isolated ileum to acetylcholine (32 x 10(-2) microg/ml) and the methanol extract (650 microg/ml) induced contractions suggesting a mode of action via cholinergic system. Luteolin and apigenin and iridoid glucosides (taxiphilin and 8-epi-deoyganic acid) might be responsible at least in part for the observed effect.     

素馨花中总环烯醚萜苷提取工艺的研究

目的研究素馨花中总环烯醚萜苷的最佳提取工艺。方法以紫外分光光度法测定总环烯醚萜苷的含量,计算总环烯醚萜苷收率(按药材计算)为评价指标,采用L9(34)正交实验法对水冷浸、水煎煮、醇冷浸、醇回流的各个因素进行考察。结果水冷浸最佳条件为A3B3C3,水煎煮最佳条件为A3B1C3,醇冷浸最佳条件为A2B1C3,醇回流最佳条件为A3B3C1。各种方法的最优组合所得的总环烯醚萜苷收率差别不大。结论该研究考察的提取工艺具有良好的稳定性和重复性,可为素馨花药材的进一步开发利用提供科学依据。     

Endothelium-dependent and independent vasorelaxation induced by an n-butanolic fraction of bark of Scutia buxifolia Reiss (Rhamanaceae)

Ethnopharmacological relevance

Scutia buxifolia has been widely used in Brazilian folk medicine as an anti-hypertensive agent.We evaluated the vascular effects and mechanism involved in the relaxation of aorta induced by an n-butanolic fraction (BuOH) from Scutia buxifolia.

Materials and Methods

Rat aortic rings precontracted by phenylephrine (1 μM) were exposed to cumulative concentrations (3–3000 μg/ml) of crude extracts or fractions obtained from bark or leaves of Scutia buxifolia. Classical receptor antagonists, channel and enzymatic inhibitors were used to check the mechanisms involved.

Results

The crude extracts of both leaves and bark of Scutia buxifolia, as well as several fractions, were able to induce partial or total relaxation of rat aortic rings. The BuOH fraction of bark of Scutia buxifolia was the most potent in endothelium-intact (E+) preparations, and also induced a partial, but very significant relaxation in endothelium-denuded (E−) vessels. The non-selective nitric oxide synthase inhibitor L-NAME, as well as the soluble guanylate cyclase inhibitor ODQ, vanished the relaxation in E+. In E− preparations, K⁺ channel blockers, such as tetraethylammonium, glibenclamide, 4-aminopyridine, and the large-conductance calcium-activated K⁺ channel blocker iberiotoxin, were able to significantly reduce the maximum relaxation elicited by BuOH fraction.

Conclusion

Our results demonstrated that BuOH fraction obtained from barks of Scutia buxifolia induced both endothelium-dependent and -independent relaxation in rat aortic rings. The endothelium-dependent relaxation is fully dependent on NO/cGMP system, while direct activation of K⁺ channels may explain, at least in part, the endothelium-independent relaxation induced by BuOH fraction of Scutia buxifolia.     

Anti-inflammatory activity and lipid peroxidation inhibition of iridoid lamiide isolated from Bouchea fluminensis (Vell.) Mold. (Verbenaceae)

Anti-inflammatory activity of an ethanolic extract from Bouchea fluminensis leaves was demonstrated. From de ethanolic extract, the active compound was isolated and characterized as the iridoid lamiide. The activity of lamiide on rat-brain phospholipid peroxidation showed a powerful effect (IC(50)=0.92+/-0.01 mM) and an anti-inflammatory activity in carrageenin-induced paw edema test (ED(50)=62.3+/-7 mg/kg weight).     

Effects of Kaempferia parviflora Wall. Ex Baker on endothelial dysfunction in streptozotocin-induced diabetic rats

Aim of the study

The aim of the present study was to investigate an ethanolic extract of Kaempferia parviflora (KPE) reduces oxidative stress and preserves endothelial function in aortae from diabetic rats.

Materials and methods

Diabetes was induced in Sprague-Dawley rats by streptozotocin (STZ) treatment (55 mg/kg i.v.). Vascular reactivity and superoxide generation were assessed in aortic rings using standard organ bath techniques and lucigenin-enhanced chemiluminescence, respectively.

Results

Eight weeks after STZ treatment blood glucose was elevated compared to citrate treated control rats and there was an increased aortic generation of superoxide anion. In aortic rings acetylcholine-induced relaxation was impaired whereas endothelium-independent relaxation to sodium nitroprusside was unaffected. When aortic rings were acutely exposed to KPE (1, 10 and 100 μg/ml) there was a significant reduction in the detection of superoxide anion and enhanced relaxation to acetylcholine. Two separate groups of rats (control and diabetic) were orally administered daily with KPE (100 mg/kg body weight) for 4 weeks. KPE treatment reduced superoxide generation and increased the nitrite levels in diabetic aortae, and enhanced acetylcholine-induced relaxation. In the presence of N^G-nitro-l-arginine (l-NNA), the relaxation to acetylcholine in aortic rings of diabetic rats was only partially inhibited, but was totally abolished in aortic rings from the KPE-treated diabetic rats. Indomethacin did not affect relaxation to acetylcholine in aortic rings of any group.

Conclusions

These results suggest that KPE, acutely in vitro or after 4 weeks administration in vivo, reduces oxidant stress, increases NO bioavailability and preserves endothelium-dependent relaxation in aortae from diabetic rats.     

中药玄参的研究进展

文章综述了玄参近年来在化学成分、药理活性、质量评价等方面的研究进展,化学成分主要含有环烯醚萜、苯丙素苷、有机酸及挥发油等;药理研究显示玄参具有保肝、抗血小板聚集、抗缺血、抗氧化等作用;其质量控制方法主要以所含主要成分哈帕苷和喻帕俄苷等作为药材和制剂的质量控制指标。     

Verbaspinoside, a new iridoid glycoside from Verbascum spinosum

A new iridoid glycoside, verbaspinoside (1), was isolated from the aerial parts of Verbascum spinosum. Its structure was elucidated on the basis of chemical and spectral data as 6-O-[(2' '-O-trans-cinnamoyl)-alpha-L-rhamnopyranosyl]-catalpol. Additionally, three known iridoids (aucubin, catalpol, and ajugol) and three phenylpropanoid glycosides [acteoside, angoroside A (2), and angoroside C (3)] were isolated and identified.     

Endothelium-dependent contraction of rat thoracic aorta induced by gallic acid

The vascular effect of a component of hydrolysable tannins, gallic acid, was examined in isolated rat thoracic aorta. Gallic acid exerted a contractile effect on the phenylephrine- or prostaglandin F(2/alpha)-precontracted endothelium-intact arteries. In endothelium-denuded arteries, the contractile response to-gallic acid was absent. Pretreatment with N(G)-nitro-L-arginine methyl ester (30 microM) abolished the gallic acid-induced contraction. Pretreatment with indomethacin (10 microM) or BQ610 (100 nM) had no observed effect. Pretreatment with gallic acid (1-10 microM) significantly attenuated the relaxation induced by acetylcholine, and that with 10 microM gallic acid also reduced the potency of sodium nitroprusside in the relaxation, without a reduction in efficacy, in endothelium-denuded arteries. These findings indicate that gallic acid induced endothelium-dependent contraction and strongly inhibited the endothelium-dependent relaxation rather than the endothelium-independent relaxation, probably through inhibition of endothelial nitric oxide (NO) production. Since NO plays an important role in vasodilative regulation and inflammatory disorders, these findings may also indicate that gallic acid interferes with the inflammatory responses.     

Iridoid glycosides from Globularia trichosantha

A new iridoid glycoside, deacetylalpinoside (2), was isolated from the aerial parts of Globularia trichosantha together with nine known iridoid glycosides: catalpol, 10-O-benzoyl-catalpol, aucubin, asperuloside, deacetylasperuloside, asperulosidic acid, scandoside, geniposidic acid, and alpinoside (1). From the underground parts of the same plant, two new bisiridoid glycosides, globulosides A (3) and B (4); a known iridoid glycoside, globularidin; a lignan glycoside, liriodendrin; and seven phenylethanoid glycosides, arenarioside, verbascoside (= acteoside), isoacteoside, crenatoside, isocrenatoside, and trichosanthosides A and B, were isolated. Compounds 2-4 are new iridoids containing an 8,9 double bond representing a rare carbon skeleton. Their structures were established by spectroscopic methods.     

Antispasmodic and anti-diarrhoeal effect of Satureja hortensis L. essential oil

Satureja hortensis L. (Lamiaceae) is an annual herb that is used in the traditional medicine of Iran for treating stomach and intestinal disorders. The antispasmodic activity of S. hortensis essential oil (SHEO) was assessed on contractions of isolated ileum, induced by KCl and acetylcholine, and compared with the effect of atropine and dicyclomine. SHEO inhibited the response to 80 mM KCl in a concentration-dependent manner (pD(2)=1.55+/-0.09 microg/ml; this is negative log concentration of SHEO causing 50% of maximum inhibition) and attenuating the maximum inducible response of acetylcholine concentration-response curve. Effect of SHEO on KCl was similar to that of dicyclomine. Dicyclomine (3.46 and 34.6 ng/ml) also reduced the response to acetylcholine on rat isolated ileum without altering the maximum response and shifted the acetylcholine concentration-response curve to the right by 16-fold at 34.6 ng/ml (100 nM) bath concentration, while atropine only inhibited the response to acetylcholine. This study shows that SHEO is a relaxant of rat isolated ileum. In addition to antispasmodic activity in vitro, essential oil of this plant at a dose of 0.1 ml/100 g inhibited castor oil induced diarrhoea in mice. As the inhibition of contractile overactivity of the ileum is the base of the treatment of some gastrointestinal disorders such as colic, SHEO may have clinical benefits for treatment of these conditions.