酢浆草提取物中总黄酮含量的分光光度法测定

目的测定酢浆草不同提取物中总黄酮的含量。方法以异荭草素为标准品,采用分光光度法测定酢浆草提取物中总黄酮的含量。结果异荭草素在10.096～80.768μg/ml范围内呈良好的线性关系;平均回收率(n=6)为98.7%,RSD为1.70%。结论方法灵敏度高、稳定性好,可用于酢浆草提取物的质量控制。     

Antioxidant flavone glycosides from the leaves of<Emphasis Type="Italic">Sasa borealis</Emphasis>

Sasa borealis (Poaceae) is a perennial medicinal plant which is a major source of bamboo leaves in Korea. Then-BuOH extract ofS. borealis leaves exhibited significant antioxidant activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and a cytoprotective effect against oxidative damage in HepG2 cells. Bioactivity-guided fractionation by column chromatography led to the isolation of two antioxidative flavonoid C-glycoside derivatives, isoorientin (2) and isoorientin 2”-O-α-i_-rhamnoside (4) along with tricin 7-0-β-D-glucopyranoside (1) and apigenin 6-C-β-D-xylopyranosyl-8-C-β-D-glucopyranoside (3). Their structures were identified on the basis of chemical and spectroscopic methods. The radical scavenging activity and cytoprotective effect against oxidative damage of all the isolated compounds were also evaluated. Isoorientin (2) and isoorientin 2-O-α-L-rhamnoside (4) showed potent free radical scavenging activity with 1C₅₀ values of 9.5 and 34.5 μM, respectively, and strong cytoprotective effects againstt-BOOH-induced oxidative damage in HepG2 cells, at very low concentrations of 1.1 μM isoorientin and 0.8 μM isoorientin 2-O-α-L-rhamnoside. This is the first report of the isolation and antioxidant activity of compounds 2 and 4 from S.borealis.     

Metabolism and plasma pharmacokinetics of isoorientin,a natural active ingredient,in Sprague-Dawley male rats after oral and intravenous administration

Abstract

1. Several pharmacological effects have been revealed on isoorientin, suggesting its potential medicinal prospects. The metabolic and plasma pharmacokinetic profiles of isoorientin were investigated in rats.

2. For intra-gastric gavage, parent drug and three metabolites were detected in urine and feces by HPLC–MS/MS, but only one metabolite was found in plasma and identified as isoorientin 3′- or 4′-O-sulfate (M1) according to MS and UV absorbance spectra.

3. After a single i.v. administration of isoorientin (5, 10, or 15?mg/kg B.W.) in rats, linear pharmacokinetic property was observed with favorable terminal half-lives (1.67?±?1.32–2.07?±?0.50?h). After a single p.o. administration of isoorientin (150?mg/kg B.W.) in rats, plasma isoorientin concentration was low, but the concentration of M1 was comparatively high. Low systemic exposure of oral isoorientin in rats could result from its low aqueous solubility and extensive first-pass metabolism, and plasma concentration of M1 can be used as a biomarker of isoorientin intake. Isoorientin showed low oral bioavailability (8.98?±?1.07%), and had about 6% or 45% dose recovery in urine or feces, respectively, 72?h after intra-gastric gavage.

4. These studies are the first to describe the pharmacokinetics of isoorientin via i.v. or p.o. dosing, providing important information for understanding its process in vivo.     

Gluconeogenesis inhibition and phytochemical composition of two Cecropia species

Aim of the study

Cecropia obtusifolia and Cecropia peltata are plants highly used by the Mexican diabetic population to treat type 2 diabetes. Previous studies have assessed their hypoglycemic effect in animal models and in type 2 diabetic patients. Both plants contain cholorogenic acid, an inhibitor of glucose-6-phosphate translocase. In this work, we found a mechanism by which to understand how these plants could produce the observed hypoglycemic effect according to their traditional use. To test the hypothesis that targeting gluconeogenesis with an inhibitor of Gl-6-P translocase could result in a reduction of hepatic glucose production, we examined the effects of Cecropia obtusifolia and Cecropia peltata on gluconeogenesis (in vivo) and the activity of the enzyme (in vitro).

Materials and methods

The extracts of the two plants were analyzed by HPLC to confirm their phytochemical composition. To test the inhibition of gluconeogenesis in vivo, a pyruvate tolerance test (2 g/kg) was performed in 18-h fasted n5-STZ rats. The effect of the extracts (Cecropia obtusifolia and Cecropia peltata 150 mg/kg) on glucose-6-phosphatase activity was assayed in vitro with intact rat liver microsomes.

Results

Using HPLC-DAD, we confirmed that the main components of both species are chlorogenic acid and isoorientin. Diabetic rats treated with the extracts showed a lower glucose curve. The tested extracts were able to reduce the increase in the glucose blood level, and they inhibited the glucose-6-P activity with IC₅₀s of 224 μg/ml for Cecropia obtusifolia aqueous, 160 μg/ml for Cecropia obtusifolia butanolic, 146 μg/ml for Cecropia peltata aqueous and 150 μg/ml for Cecropia peltata butanolic.

Conclusions

The results of the experiments presented here suggest that the administration of both plants can improve glycemic control by blocking the hepatic glucose output, especially in the fasting state. These data support the traditional use of the plants as “agua de uso”, a cold infusion of the plant consumed over the course of a day.     

HPLC法同时测定紫果西番莲叶中荭草素、异荭草素与牡荆素的含量

目的:建立同时测定紫果西番莲叶中荭草素、异荭草素与牡荆素含量的方法。方法:采用高效液相色谱法。色谱柱为Inertsil C18(250mm×4.6mm,5μm),流动相为乙腈-0.1%磷酸溶液(梯度洗脱),检测波长为350nm,流速为1mL·min-1,柱温为30℃。结果:异荭草素、荭草素与牡荆素的检测浓度分别在0.015～0.150mg·mL-1(r=0.9998)、0.012～0.120mg·mL-1(r=0.9998)、0.012～0.120mg·mL-1(r=0.9994)范围内与各自峰面积积分值呈良好线性关系;平均回收率分别为99.04%(RSD=0.80%,n=6)、99.30%(RSD=1.03%,n=6)、98.92%(RSD=1.11%,n=6)。结论:本方法简便、准确,可为紫果西番莲叶的进一步开发利用提供质量控制依据。     

Effect of isoorientin on intracellular antioxidant defence mechanisms in hepatoma and liver cell lines

Isoorientin (ISO) is considered one of the most important flavonoid-like compounds responsible for health benefits, including the prevention of liver damage as well as antioxidant, anti-inflammatory, and anti-nociceptive activities. Our previous study showed that ISO inhibited the proliferation of hepatoma cells through increasing intracellular ROS levels. Interestingly, ISO protects rat liver cells against hydrogen peroxide-induced oxidation stress by decreasing intracellular ROS levels. Why are there different effects of ISO on ROS in different physiological and pathophysiological circumstances? The present study investigated the effect of ISO on mitochondrial respiratory chain complexes and phase II detoxifying enzyme activities in human hepatoblastoma cancer cells (HepG2), buffalo rat liver cells (BRL-3A) and human liver cancer cells (HL-7702). The results showed that intracellular ROS levels and the protein expression of the respiratory chain complexes was significantly (p < 0.01) higher in the HepG2 cells than in the BRL-3A and HL-7702 cells. Additionally, ISO notably (p < 0.01) increased ROS levels in the HepG2 cells, while no significance was found in the BRL-3A and HL-7702 cells. Furthermore, in the HepG2 cells, the protein expression of the respiratory chain complexes and the phase II detoxifying enzyme activities and GSH content were decreased by ISO (p < 0.01), while ISO, in a certain range, enhanced the expression of the protein complexes and the phase II detoxifying enzyme activities and GSH content in BRL-3A and HL-7702 cells. All of these results demonstrated, for the first time, that ISO possesses a notable hepatoprotective effect, which might be mediated through the respiratory chain complexes and phase II detoxifying enzyme activities.     

HPLC 法测定竹叶提取物中荭草苷、异荭草素、牡荆素和异牡荆素的含量

目的：建立竹叶提取物中荭草苷、异荭草素、牡荆素和异牡荆素含量的HPLC测定方法。方法：色谱柱：Agilent HC-C18（250mm ＆#215;4．6mm,5μm）;流动相：乙腈-2％冰醋酸（14∶86）;流速：1mL/min;检测波长350nm;柱温：40℃。结果：线性范围为荭草苷在2．0760～12．4560μg（r＝0．9999）;异荭草素在3．9400～23．6400μg（r＝0．9997）;牡荆素在0．2740～1．6440μg（r＝0.9999）;异牡荆素在0．7690～4．6140μg（r＝0．9999）。荭草苷平均回收率为99．36％,RSD为2．39％;异荭草素平均回收率为99.69％,RSD为1．89％;牡荆素平均回收率为100．04％,RSD为1．49％;异牡荆素平均回收率为100．64％,RSD为1．61％。结论：该方法准确可靠、简单易行,适用于竹叶提取物中荭草苷、异荭草素、牡荆素和异牡荆素的含量测定。     

HPLC法测定导赤冲剂中异牡荆苷和异荭草苷的含量

目的 建立导赤冲剂中异牡荆苷和异荭草苷的含量测定方法.方法 采用高效液相色谱法,色谱柱为迪马C18柱,流动相为四氢呋喃-乙腈-0.2％磷酸水溶液(66∶ 22∶ 12),流速为1.0 mL?nin-1,柱温为35℃,检测波长为330 nm.结果 异荭草苷在0.82～4.08 μg范国内与峰面积积分值呈良好的线性关系(r=0.9990),平均加样回收率为96.4％,RSD为2.7％;异牡荆苷在0.79～3.96 μg范围内与峰面积积分值呈良好的线性关系(r=0.9999),平均加样回收率为98.8％,RSD为2.6％.结论 建立的含量测定方法简便、准确、灵敏,可用于导赤冲剂中异牡荆苷和异荭草苷的含量测定.     

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.