Platycodi Radix Research Articles

Prostaglandin-H-synthase (PGHS)-1 and -2 microtiter assays for the testing of herbal drugs and in vitro inhibition of PGHS-isoenzyms by polyunsaturated fatty acids from Platycodi radix

In order to test inhibition of prostaglandin-H-synthase-1 and -2 (PGHS-1 and -2) by plant extracts, we have established two enzyme based in vitro assays with enzyme immunoassay (EIA) evaluation. The assays have been evaluated with known synthetic inhibitors and with plant extracts. In a screening of traditionally used Chinese herbs for anti-inflammatory activity, a series of n-hexane and dichloromethane extracts showed significant inhibitory effect in comparison with the known specific PGHS-2 inhibitors NS-398 (IC(50) = 2.6 microM) and nimesulide (IC(50) = 36 microM). The lipophilic extracts of the Chinese drug Jiengeng, the dried roots of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae), showed good inhibitory activity against both PGHS isoenzymes. The directly prepared DCM-extract exhibited better activity against PGHS-2 (IC(50) = 4.0 microg/ml) than against PGHS-1 (IC(50) = 17.6 microg/ml). We identified fatty acids as main active constituents and quantified them. Linoleic acid showed the highest content (ca. 20% of the dried extract) and a high and preferential PGHS-2 inhibitory activity (IC(50) (PGHS-1) = 20 microM; IC(50) (PGHS-2) = 2 microM). The comparison of the concentration of linoleic acid and the inhibitory activity of the direct DCM-extract showed, that linoleic acid is mainly responsible for the in vitro activity of the extract on PGHS-2.

Antiobese and hypolipidemic effects of platycodin saponins in diet-induced obese rats: evidences for lipase inhibition and calorie intake restriction

To investigate how and to what extent platycodin saponin (PS) from Platycodi Radix exerts a favorable influence on obesity and hyperlipidemia. Sprague-Dawley rats were fed with a high fat (HF) diet for 4 weeks and then the animals were treated with 35 or 70 mg / kg of PS for another 4 weeks. Changes in body weight and daily calorie intake were measured regularly during the experimental period and the degree of linear correlation for the above two variables was further analyzed. The in vitro lipase inhibition of each PS compound and the in vivo fecal lipid excretion were examined in hope of revealing their relationship. The concentrations of hepatic triglyceride and cholesterol in serum. The body weight reduction (13+/-4% vs HF control, P<0.05) by PS administration was highly correlated to the food intake restriction (Pearson's linear coefficient r=0.752, P<0.005). The in vitro inhibition of lipase by each isolated compound and mixture of PS were virtually identical. Consequently, the fecal TG excretion was increased by 2.1-3.2 folds depending on the dose of PS. The serum TG and LDL-cholesterol concentrations were decreased without noticeable changes in HDL-cholesterol levels. Concomitantly, the contents of the hepatic TG, cholesterol, and the liver surface fat pads were decreased in ubiquity, but no noticeable biochemical abnormalities or histological tissue damages were observed. The administration of PS produced profound effects on the control of obesity and lipid metabolism, which resulted in LDL-cholesterol reduction. PS also caused a remarkable reduction in calorie intake, which was highly correlated to the body weight loss. These results suggest that PS has a greater role in anti-obesity, hypolipidemia, and liver protection than previously thought. Hence, PS could be a potential therapeutic alternative in the treatment of obesity and hyperlipidemia.

In vitro inhibitory effect of triterpenoidal saponins from platycodi radix on pancreatic lipase

In the process of investigating anti-obesity effect of Platycodi Radix, we found that aqueous extract of Platycodi Radix might inhibit intestinal absorption of dietary fat by inhibiting pancreatic lipase (PL) activity. In order to clarify the anti-obesity mechanism of Platycodi Radix, activity-guided isolation was performed to find active components. The total saponin fraction of Platycodi Radix appeared to have a potent inhibitory activity against the hydrolysis of triolein emulsified with phosphatidycholine by pancreatic lipase in vitro. Based on these results, further purification of active components yielded 10 known triterpenoidal saponins, among these compounds, platycodin A, C, D, and deapioplatycodin D exhibited significant inhibitory effects on PL at the concentration of 500 microg/mL with 3.3, 5.2, 34.8, and 11.67% pancreatic lipase activity vs control, respectively. Platycodin D was found to inhibit the PL activity in a dose-dependent manner. Therefore, the anti-obesity effect of Platycodi Radix might be due to the inhibition of pancreatic lipase by its saponins.

Suppressive effects ofPlatycodon grandiflorum on the progress of carbon tetrachloride-lnduced hepatic fibrosis

The suppressive effects of Platycodi Radix (Changkil: CK), the root of Platycodon grandiflorum A. DC (Campanulaceae), on the progress of acute carbon tetrachloride (CCl4)-induced hepatic fibrosis were investigated in the rat. CK significantly suppressed CCl4-induced hepatic necrosis and inflammation, as determined by the serum enzymatic activities of alanine and aspartate aminotransferase and serum tumor necrosis factor-alpha levels, in dose-dependent manners. In addition, the increased hepatic fibrosis after acute CCl4 treatment was suppressed by the administration of CK. CK also significantly prevented the elevation of hepatic alpha1 (I) procollagen (type I collagen) mRNA and alpha-smooth muscle actin (alpha-SMA) expressions in the liver of CCl4-intoxicated rats and also suppressed the induction of alpha-SMA and type I collagen in cultured hepatic stellate cells, in dose-dependent manners. These results suggest that the suppressive effects of CK against the progress of acute CCl4-induced hepatic fibrosis possibly involve mechanisms related to its ability to block both hepatic inflammation and the activation of hepatic stellate cells.

Determination of the kinetic properties of platycodin D for the inhibition of pancreatic lipase using a 1,2-diglyceride-based colorimetric assay

A 1, 2-diglyceride-based multi-step colorimetric assay to measure the pancreatic lipase activity was applied for the determination of the kinetic profiles of the lipase inhibition with a slight modification and the validity verification. With this assay method, our study revealed that platycodin D, one of major constituents of Platycodi Radix, inhibits the pancreatic lipase activity in a competitive type, with the value of Kl being 0.18 +/- 0.02 mM. In addition, PD has affected the values of Km,app and Kcat/Km in a dose- dependent manner. The results shed a meaningful light on how PD mediates lipid metabolism in the intestinal tracts. On the other hand, since the revised assay is sensitive, rapid, and does not affect the accuracy to the kinetic properties, it is applicable not only to evaluation of the kinetic properties of the pancreatic lipase, but also to high-throughput screening of pancreatic lipase activity.

Determination of the kinetic properties of platycodin D for the inhibition of pancreatic lipase using a 1,2-diglyceride-based colorimetric assay.

A 1,2-diglyceride-based multi-step colorimetric assay to measure the pancreatic lipase activity was applied for the determination of the kinetic profiles of the lipase inhibition with a slight modification and the validity verification. With this assay method, our study revealed that platycodin D, one of major constituents of Platycodi Radix, inhibits the pancreatic lipase activity in a competitive type, with the value of KI being 0.18+/-0.02 mM. In addition, PD has affected the values of K(m,app) and Kcat/Km in a dose-dependent manner. The results shed a meaningful light on how PD mediates lipid metabolism in the intestinal tracts. On the other hand, since the revised assay is sensitive, rapid, and does not affect the accuracy to the kinetic properties, it is applicable not only to evaluation of the kinetic properties of the pancreatic lipase, but also to high-throughput screening of pancreatic lipase activity.

An aqueous extract of Platycodi radix inhibits LPS-induced NF-κB nuclear translocation in human cultured airway epithelial cells

We investigated the effects of aqueous extract from Platycodi radix (AEPR), a traditional drug used to treat acute lung inflammatory disease, on lipopolysaccharide (LPS)-induced inflammation in A549 human cultured airway epithelial cells. Nuclear factor-kappaB (NF-kappaB) and its inhibitory regulator, inhibitory kappaB (I-kappaB), play crucial roles in LPS-induced inflammatory response. We show that LPS-induced nuclear translocation of NF-kappaBp65 is inhibited by AEPR. LPS-induced expression of I-kappaBalpha, which is expressed by LPS-induced activation of NF-kappaB, is inhibited by AEPR as well. Besides LPS-induced expression of a group of genes, such as tumor necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), are repressed by AEPR. We also found that expression of heat shock protein 70 (Hsp70), which has an anti-inflammatory activity, is increased by AEPR plus LPS. These results suggest that AEPR may act as a therapeutic agent for inflammatory disease through regulating the activity of NF-kappaB and expression of inflammatory genes.

Evaluations of Saponin Properties of HPLC Analysis of Platycodon grandiflorum A.DC.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Evaluations of saponin properties of HPLC analysis of Platycodon grandiflorum A.DC

Platycodon root, one of the most important Chinese herbal medicines, has been used as an antiphlogistic, antitusivie, and expectorant agent since ancient times. In the Japanese Pharmacopoeia XIV this is listed as the root of Platycodon grandiflorum A. De Candolle (Campanulaceae) and called KIKYOU (Platycodi Radix) in Japanese. HPLC analysis showed that commercial samples of P. Radix all contained platycodins, and a total of 12 peaks were identified by co-HPLC analysis with authentic samples isolated earlier from this laboratory. The peak purity and identity were checked with a photodiode array detector. The contents of the major saponins, platycodins A, C, and D, were determined and the peak-area ratios of platycodins A, C, and D, were shown to be correlated with their sources of origin. Fourteen commercial samples of Platycodon root, the origin of which was Platycodon grandiflorum, were collected from China (5 samples), Korea (5 samples), and Japan (4 samples). The commercial samples from China, Korea, and Japan each gave a distinct HPLC pattern with peak-area ratio of platycodins A, C, and D, of 1:2:3 and 2:8:1, respectively. HPLC analysis showed that those on the Japanese market were either imported from China or Korea based upon their HPLC patterns.

길경 수용액 추출물에 의한 인체 폐암세포의 apoptosis 유발에 관한 연구

전통 한의학에서 많이 사용되는 길경(Platycodi radix)은 도라지(Platycodon grandiflorum A. DC)의 뿌리 껍질을 벗기거나 또는 그대로 말린 것을 말하며, 염증성 호흡기 질환에 많이 사용되어져 오고 있다. 본 연구에서는 길경 수용액 추출물의 항암 활성 기전해석의 일환으로 A549 인체 폐암세포의 성장에 미치는 영향을 조사하였다. 길경 추출물의 처리에 의하여 처리 농도 의존적으로 암세포의 성장이 억제되었으며, 이는 apoptosis의 유발과 관련이 있었다. 즉 염색체 응축에 의한 apoptotic body의 출현과 sub-Gl기에 속하는 세포의 빈도가 길경 추출물 처리에 의하여 농도 의존적으로 증가하였다. Immunoblot 및 RT-PCR분석에서 길경 추출물의 처리에 의하여 Bcl-2의 mRNA 및 단백질의 발현은 감소되었으며, Bax의 발현이 증가됨을 알 수 있었다. 또한 길경 추출물의 처리에 의하여 caspase-3가 활성화되었으며, 이에 따른 PARP 및 <TEX>$\beta$</TEX>-catenin의 단백질 발현 감소 현상을 관찰할 수 있었다. 이러한 결과들은 길경 추출물을 이용한 인체 암세포의 성장억제제의 개발 가능성이 있음을 시사하여 준다. Platycodi Radix, the root of Platycodon grandiflorum, commonly known as Doraji, is used as a traditional oriental medicine. Extracts from the roots of P grandiflorum have been reported to have wide ranging health benefits. In the present study, we investigated the effects of an aqueous extract from the roots of P. grandiflorum (AEPG) on the growth of human lung carcinoma A549 cells. Upon treatment with AEPG, a concentration-dependent inhibition of cell growth was observed and cells developed many of the hallmark features of apoptosis, including condensation of chromatin. Flow cytometry analysis confirmed that AEPG increased populations of apoptotic-sub Gl phase. Immunoblot and quantitative RT-PCR analyses indicated that the expressions of Bcl-2 was down-regulated but Bax was up-regulated in AEPG-treated A549 cells. The expression of active form of caspase-3 by AEPG treatment was markedly increased, and the levels of poly(ADP-ribose) polymerase (PARP) and <TEX>$\beta$</TEX>-catenin, its target proteins, were decreased in a concentration dependent manner. Taken together, these findings suggest that P. grandiflorum has strong potential for development as an agent for prevention against human lung cancer.

Saponins from Platycodi Radix Ameliorate High Fat Diet–Induced Obesity in Mice

We examined the effects of crude saponins isolated from Platycodi radix on the degree on fat storage induced in mice by feeding a high fat diet for 9 wk. We reported previously that feeding mice a high fat diet for a longer time caused obesity and fatty liver compared with those fed a low fat diet, nonpurified diet. Feeding a high fat diet containing 10 or 30 g/kg crude saponins prevented the body and parametrial adipose tissue weight increases and hepatic steatosis of mice fed the high fat diet alone. Furthermore, crude saponins (375 mg/kg) inhibited the elevations in blood triacylglycerol in rats orally administered a lipid emulsion compared with that of rats given the lipid emulsion alone. Previously, we reported that crude saponins inhibited pancreatic lipase activity in vitro. To identify the active substance(s) of crude saponins, we examined the effects of purified platycodin D, the primary saponin in the crude mixture, on pancreatic lipase activity and on the blood triacylglycerol elevation in rats administered the oral lipid emulsion tolerance test. Platycodin D (0.5 and 1.0 g/L) inhibited pancreatic lipase activity in vitro and at a dose of 244 mg/kg, inhibited the elevation of blood triacylglycerol. Therefore, the antiobesity effect of the crude saponins in mice fed a high fat diet may be due to the inhibition of intestinal absorption of dietary fat by platycodin D.

Protective effect of Platycodi radix on carbon tetrachloride-induced hepatotoxicity

The protective effects of a Platycodi radix (Changkil: CK), the root of Platycodon grandiflorum A. DC ( Campanulaceae) on carbon tetrachloride (CC1 4)-induced hepatotoxicity and the possible mechanisms involved in this protection were investigated in mice. Pretreatment with CK prior to the administration of CC1 4 significantly prevented the increased serum enzymatic activities of alanine and aspartate aminotransferase in a dose-dependent manner. In addition, pretreatment with CK also significantly prevented the elevation of hepatic malondialdehyde formation and the depletion of reduced glutathione content in the liver of CC1 4-intoxicated mice. However, hepatic reduced glutathione levels and glutathione S-transferase activities were not affected by treatment with CK alone. CC1 4-induced hepatotoxicity was also essentially prevented, as indicated by a liver histopathologic study. The effects of CK on the cytochrome P450 (P450) 2E1, the major isozyme involved in CC1 4 bioactivation were also investigated. Treatment of mice with CK resulted in a significant decrease of P450 2E1-dependent p-nitrophenol and aniline hydroxylation in a dose-dependent manner. CK showed antioxidant effects in FeCl 2–ascorbate-induced lipid peroxidation in mice liver homogenate and in superoxide radical scavenging activity. Our results suggest that the protective effects of CK against CC1 4-induced hepatotoxicity possibly involve mechanisms related to its ability to block P450-mediated CC1 4 bioactivation and free radical scavenging effects.

Platycodi Radix Affects Lipid Metabolism in Mice with High Fat Diet–Induced Obesity

An aqueous extract of Platycodi radix inhibited the hydrolysis of triolein emulsified with phosphatidylcholine by pancreatic lipase in vitro and it reduced the elevation of rat plasma triacylglycerol level 2-4 h after oral administration of a lipid emulsion containing corn oil. These preliminary results suggested that the aqueous extract of Platycodi radix may inhibit the intestinal absorption of dietary fat by inhibiting its hydrolysis. Therefore, we examined the antiobesity activity of the aqueous extract of Platycodi radix by testing whether the extract prevented the obesity induced by feeding a high fat diet to mice for 8 wk. Body weights at 3-8 wk and the final parametrial adipose tissue weights were significantly lower in mice fed the high fat diet containing 5% aqueous extract of Platycodi radix than in the controls fed the high fat diet. The aqueous extract of Platycodi radix also significantly reduced hepatic triacylglycerol concentrations that were elevated in mice fed the high fat diet alone. Inulin, which is a major component of Platycodi radix, had no effect on the hydrolysis of triolein emulsified with phosphatidylcholine by pancreatic lipase in vitro, and did not prevent obesity or the fatty liver induced by the high fat diet. On the other hand, the total saponin fraction of the aqueous extract inhibited pancreatic lipase activity in vitro. Therefore, the antiobesity effect of the aqueous extract of Platycodi radix in mice fed a high fat diet may be due in part to the inhibition of intestinal absorption of dietary fat by the saponins of Platycodi radix.

Hypoglycaemic Effects ofShokatsu-Cha(Xiao-Ke-Ca) in Streptozotocin-induced Diabetes Mellitus

Shokatsu-cha is a novel formula for diabetic mellitus based on the traditional Chinese medicine and composed of Dioscoreae rhizoma, Adenophorae radix, Rehmanniae radix, Anemarrhenae rhizoma, Platycodi radix, Salviae miltiarrhizae radix, Epimedii folium and Lycii fructus. The hypoglycaemic effect of Shokatsu-cha was evaluated in streptozotocin (STZ)-induced diabetic mice and rats. When orally administered once a day for 10 days to the mice intraperitoneally injected with STZ, the Shokatsu-cha extract suppressed the increase of the blood glucose level during administration. In the in situ intestine circulation method, the Shokatsu-cha extract and its ethanol-eluted fraction inhibited tbe glucose absorption in STZ-induced diabetic rats. The ethanol-eluted fraction also inhibited the increase of blood glucose level in an oral glucose tolerance test using diabetic mice. This study indicates that a part of the hypoglycaemic effect of Shokatsu-cha is based on its inhibitory action on intestinal glucose absorption in diabetes.

Role of Cyclic Nucleotide System in the Action of Oriental Medicinal Herbs

Tests were performed on mice in order to examine the ability of Oriental medicinal herbs to increase plasma levels of cyclic AMP in vivo. Cyclic AMP was determined by radioimmunoassay before and after administration of water decocted extracts of 218 different herbs. Of these,82 were positive. Polyphenol, a tannin-like substance, was responsible for most of the activities of the herbs except Platycodi Radix. The active constituents in Platycodi Radix were successfully purified and were shown to be saponins. Further, tannic acid and its degenerates, pyrogallol and purpurogallin, which are produced by peroxidase from pyrogallol, were shown to have adenylate cyclase stimulatory, COMT inhibitory and phosphodiesterase inhibitory activities, respectively. Peroxidase activities were varied according to the mouse strain, suggesting that the efficacy of Oriental medicinal herbs is determined by the interaction between the herbs and the metabolism of the patient. Long term peroral administration of Shôseiryû-tô which has been used for bronchial asthma, enhances the plasma cyclic AMP responses to isoprenaline and histamine in mice and restores the down regulation induced by long term subcutaneous injections of catecholamine, indicating that there is some effect on the β-adrenoceptors and H2 receptors. Evodiae Fructus contains 30-40n mole/g dry wt. cyclic GMP and Zizyphi Fructus contains 30-50 and 100-500n mole/g dry wt. cyclic GMP and cyclic AMP, Respectively. In natural occurrance, these values are the highest among not only plants but also animal tissues. Chronic and general pharmacological action by Oriental medicinal herbs can be explained partly via its effect on the cyclic nucleotide system.

Effects of crude drugs on congestive edema.

Screening tests of crude drugs was carried out using a model system of congestive edema in rats. Some crude drugs containing saponin, i.e., Akebiae Caulis, Platycodi Radix, Polygalae Radix, and Mi-saponin (which resembles senega saponin in chemical structure) showed anti-edmatous and diuretic actions. Concomitant use of phenylbutazone with Mi-saponin resulted in an increase in urine volume and anti-edmatous action.

Interaction of d-pseudoephedrine with water soluble extracts of Platycodi Radix on acute toxicity (author's transl)

Effect of various combinations of Platycodi Radix water soluble extracts (Pla), 1-ephedrine (1-eph), d-pseudoephedrine (d-pseudo) and Ipecacuanhae Radix water soluble extracts (Ipe) on acute toxicity were examined in mice. Oral LD50 of Ipe, d-pseudo and 1-eph was 490 (415--578) mg/kg, 1550 (1360--1767) mg/kg and 1400 (1102--1778) mg/kg, respectively, while that of Pla was over 10 g. LD50 of Pla Ipe, d-pseudo and 1-eph given intraperitoneally was 1400 (1228--1596) mg/kg 235 (210--263) mg/kg, 245 (229--262) mg/kg and 300 (259--348) mg/kg, respectively. The ratio of the predicted LD50 value, which was calculated on the assumption that each component drug would be additively toxic when combined, to the observed LD50 value was used for comparison. The combination of d-pseudo with Pla gave a significantly greater LD50 value than the predicted LD50 value, while the combination of 1-eph with Pla showed a LD50 value which was not significantly different from Finney's additive model. A combination of d-pseudo with 1-eph and Ipe, and of 1-eph with Ipe showed a LD50 value which was not significantly different from that of the additive model.

Studies on the saponins of the root of Platycodon grandiflorum A. De Candolle. I. Isolation and the structure of platycodin-D.

The chemical structure of platycodin-D, C57H92O28, [α]21D-32.3°(MeOH), which was isolated from platycodi radix (root of Platycodon grandiflorum A. DC.) was elucidated as I on the basis of physical data of platycodin-D, its derivatives and degradation products. It should be noted that platycodin-D is the first example of saponin containing apiose in the sugar moiety.