DA-9701 (Motilitone): A Multi-Targeting Botanical Drug for the Treatment of Functional Dyspepsia.

Functional dyspepsia (FD) is the most common functional gastrointestinal disorder (FGID). FD is characterized by bothersome symptoms such as postprandial fullness, early satiety, and epigastric pain or burning sensations in the upper abdomen. The complexity and heterogeneity of FD pathophysiology, which involves multiple mechanisms, make both treatment and new drug development for FD difficult. Current medicines for FD targeting a single pathway have failed to show satisfactory efficacy and safety. On the other hand, multicomponent herbal medicines that act on multiple targets may be a promising alternative treatment for FD. DA-9701 (Motilitone), a botanical drug consisting of Corydalis Tuber and Pharbitidis Semen, has been prescribed for FD since it was launched in Korea in 2011. It has multiple mechanisms of action such as prokinetic effects, fundus relaxation, and visceral analgesia, which are mediated by dopamine D2 and several serotonin receptors involved in gastrointestinal (GI) functions. In clinical studies, DA-9701 has been found to be beneficial for improvement of FD symptoms and GI functions in FD patients, while showing better safety compared to that associated with conventional medicines. In this review, we provide updated information on the pharmacological effects, safety, and clinical results of DA-9701 for the treatment of FGIDs.

Combined Application of UHPLC-QTOF/MS, HPLC-ELSD and 1 H-NMR Spectroscopy for Quality Assessment of DA-9801, A Standardised Dioscorea Extract.

INTRODUCTION: DA-9801, a standardised 50% aqueous ethanolic extract of a mixture of Dioscorea japonica and D. nipponica, is a botanical drug candidate for the treatment of diabetic neuropathy, which finished its US phase II clinical trials recently. An advanced quality control method is needed for further development of DA-9801, considering its high contents of both primary and secondary metabolites. OBJECTIVE: Development of a quality assessment strategy for DA-9801, based on the combination of UHPLC-QTOF/MS, HPLC-ELSD, and 1 H-NMR spectroscopy. METHODS: The method was developed and tested with 15 batch products of DA-9801. The steroidal saponins of DA-9801 were tentatively identified by UHPLC-QTOF/MS and were quantified with the validated HPLC-ELSD method. Primary metabolites of DA-9801 were identified and profiled using 1 H-NMR spectrometry. The batch-to-batch equivalence of DA-9801 was tested with the 1 H-NMR spectra using spectral binning, correlation analysis, and principal component analysis. RESULTS: Six major saponins of DA-9801 were tentatively identified by UHPLC-QTOF/MS. Among them, protodioscin and dioscin were quantified by the validated HPLC-ELSD method. Twenty-six metabolites were identified in 1 H-NMR spectra. The similarity between DA-9801 batches could be evaluated with the NMR spectra of DA-9801. The 1 H-NMR method also revealed that two Dioscorea species contributed distinct amino acids to the contents of DA-9801. CONCLUSION: This study validates the effectiveness of UHPLC-QTOF/MS, HPLC-ELSD, and 1 H NMR-combined method for quality control of DA-9801 and its crude materials. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacokinetics and brain distribution of tetrahydropalmatine and tetrahydroberberine after oral administration of DA-9701, a new botanical gastroprokinetic agent, in rats.

DA-9701, a new botanical gastroprokinetic agent, has potential for the management of delayed gastric emptying in Parkinson's disease if it has no central anti-dopaminergic activity. Therefore, we examined the pharmacokinetics of DA-9701 components having dopamine D2 receptor antagonizing activity, tetrahydropalmatine (THP) and tetrahydroberberine (THB), following various oral doses (80-328 mg/kg) of DA-9701. The distribution of THP and THB to the brain and/or other tissues was also evaluated after single or multiple oral administrations of DA-9701. Oral administration of DA-9701 yielded dose-proportional area under the plasma concentration-time curve (AUC0-8 h) and maximum plasma concentration (Cmax) values for THP and THB, indicating linear pharmacokinetics (except for THB at the lowest dose). THP and THB's large tissue-to-plasma concentration ratios indicated considerable tissue distribution. High concentrations of THP and THB in the stomach and small intestine suggest an explanation for DA-9701's potent gastroprokinetic activity. The maximum concentrations of THP and THB in brain following multiple oral DA-9701 for 7 d (150 mg/kg/d) was observed at 30 min after the last oral DA-9701 treatment: 131±67.7 ng/g for THP and 6.97±4.03 ng/g for THB. Although both THP and THB pass through the blood-brain barrier, as indicated by brain-to-plasma concentration ratios greater than unity (approximately 2-4), oral administration of DA-9701 at the effective dose in humans is not expected to lead to sufficient brain concentrations to exert central dopamine D2 receptor antagonism.

Reduced Food-Effect on Intestinal Absorption of Dronedarone by Self-microemulsifying Drug Delivery System (SMEDDS).

The oral absorption of dronedarone (DRN), a benzofuran derivative with anti-arrhythmic activity, is significantly affected by food intake. The absolute bioavailability of the marketed product (Multaq, Sanofi, U.S.) was about 4% without food, but increased to 15% when administered with a high fat meal. Therefore, to reduce the food-effect on the intestinal absorption of DRN, a novel self-microemulsifying drug delivery system (SMEDDS) was formulated and the comparative in vivo absorption studies with the marketed product were carried out using male beagle dogs either in the fasted or fed state. The SMEDDS consisted of the drug, Labrafil M 1944CS, and Kolliphor EL in a weight ratio of 1 : 1 : 2, rapidly formed a fine oil-in-water emulsion with a droplet size less than 50 nm. An in vivo absorption study revealed that the area-under-curve (AUC0-24 h) and maximal plasma concentration (Cmax) were 10.4-fold (p<0.05) and 8.6-fold (p<0.05) higher, respectively, after the marketed product was orally administered to beagles in the fed state when compared to those in the fasted state. This food-effect were remarkably alleviated by SMEDDS formulation, with AUC0-24 h and Cmax 2.9-fold (p<0.05) and 2.6-fold (p<0.05) higher in the fed state when compared to the fasted state, by facilitating intestinal absorption of DRN in the fasted state. The results of this study suggest that SMEDDS may decrease the differences in oral absorption of DRN between the prandial states, improving therapeutic efficacy as well as patient compliance.

DA-9801 promotes neurite outgrowth via ERK1/2-CREB pathway in PC12 cells.

In the present study, we examined the mechanisms underlying the effect of DA-9801 on neurite outgrowth. We found that DA-9801 elicits its effects via the mitogen-activated protein kinase (MEK) extracellular signal-regulated kinase (ERK)1/2-cAMP response element-binding protein (CREB) pathway. DA-9801, an extract from a mixture of Dioscorea japonica and Dioscorea nipponica, was reported to promote neurite outgrowth in PC12 cells. The effects of DA-9801 on cell viability and expression of neuronal markers were evaluated in PC12 cells. To investigate DA-9801 action, specific inhibitors targeting the ERK signaling cascade were used. No cytotoxicity was observed in PC12 cells at DA-9801 concentrations of less than 30 µg/mL. In the presence of nerve growth factor (NGF, 2 ng/mL), DA-9801 promoted neurite outgrowth and increased the relative mRNA levels of neurofilament-L (NF-L), a marker of neuronal differentiation. The Raf-1 inhibitor GW5074 and MEK inhibitor PD98059 significantly attenuated DA-9801-induced neurite outgrowth. Additionally, the MEK1 and MEK2 inhibitor SL327 significantly attenuated the increase in the percentage of neurite-bearing PC12 cells induced by DA-9801 treatment. Conversely, the selective p38 mitogen-activated protein kinase inhibitor SB203580 did not attenuate the DA-9801 treatment-induced increase in the percentage of neurite-bearing PC12 cells. DA-9801 enhanced the phosphorylation of ERK1/2 and CREB in PC12 cells incubated with and without NGF. Pretreatment with PD98059 blocked the DA-9801-induced phosphorylation of ERK1/2 and CREB. In conclusion, DA-9801 induces neurite outgrowth by affecting the ERK1/2-CREB signaling pathway. Insights into the mechanism underlying this effect of DA-9801 may suggest novel potential strategies for the treatment of peripheral neuropathy.

Gender differences in corydaline pharmacokinetics in rats.

1. Corydaline, an isoquinoline alkaloid, is one of the major active constituents in a new prokinetic botanical agent, DA-9701. It has been recommended that preclinical pharmacokinetic studies of natural medicines include both genders. Therefore, in this study, the pharmacokinetics of corydaline in male and female rats was evaluated following intravenous and oral administration of pure corydaline or DA-9701. 2. After intravenous administration of corydaline, the area under the plasma concentration-time curve (AUC) was significantly greater (by 46.4%) in female rats compared to male rats due to a 29.3% reduction in non-renal clearance in female rats. The gender difference in corydaline hepatic metabolic clearance was supported by a significantly slower metabolism of corydaline in hepatic microsomes of female rats mediated via male-specific (CYP2C11 and CYP3A2) or male-dominant (CYP3A1) CYP isozymes. 3. Following oral administration of pure corydaline or DA-9701, the AUC and Cmax values of corydaline in female rats were significantly greater (by 793% and 466% increase for corydaline administration or by 501% and 143% increase for DA-9701 administration) than in male rats. Greater F values of corydaline in female rats could be due to smaller hepatic first-pass extraction as a result of slower hepatic metabolism of corydaline. 4. However, we observed a comparable disappearance of corydaline in male and female human liver microsomes, consistent with little gender difference in CYP2C9 and CYP3A activities in humans compared to that in rats. Thus, gender differences in corydaline metabolism are not expected to occur in humans.

DA 5505: a novel topical formulation of terbinafine that enhances skin penetration and retention.

Topical fungal infections can become severe if left untreated. Efficient treatment modalities for topical fungal infections aid the penetration of antifungal agents deep into viable skin layers. Terbinafine is a fungicidal agent that inhibits ergosterol, an essential fungal component. The main objective of this study was to evaluate skin permeation and retention of a terbinafine-loaded solution containing chitosan as a film former. Comparative assessment of skin permeation and retention was performed using a prepared formulation (DA 5505) and marketed formulations of terbinafine in murine and porcine skin. To mimic fungal infection of skin, keratinized skin was induced in NC/Nga mice. In comparison with the marketed formulations, DA 5505 exhibited significantly better skin permeation. The flux, permeation coefficient, and enhancement ratio of terbinafine were remarkably increased by DA 5505 in comparison with the marketed formulations, and lag time was dramatically reduced. DA 5505 significantly increased cumulative terbinafine retention in viable skin layers in comparison with the marketed solution, suggesting enhanced efficacy. Furthermore, DA 5505 exhibited superior skin permeation in normal skin and keratinized skin. Thus, the DA 5505 formulation has the potential to effectively deliver terbinafine to superficial and deep cutaneous fungal infections.

Preparation of solid dispersion of dronedarone hydrochloride with Soluplus(®) by hot melt extrusion technique for enhanced drug release.

In order to enhance the dissolution rate of dronedarone hydrochloride (DRN), a novel Soluplus(®) (polyethyleneglycol-polyvinyl caprolactam-polyvinyl acetate grafted copolymer)-based solid dispersion (SD) was formulated using a hot melt extrusion technique. The physical characteristics determined using scanning electron microscopy and X-ray powder diffraction, revealed that the active compound was molecularly dispersed in the amphiphilic polymer in a stable amorphous form. The dissolution rate of DRN from the tablet dosage form of SD extrudate consisted of the drug and Soluplus(®) in a weight ratio of 1 : 1, and was obviously more rapid and higher than that of the intact drug and marketed product (Multaq(®), Sanofi, U.S.A.) at pH 1.2, 4.0 and 6.8. This suggests that Soluplus(®)-based SD formula can be a promising approach for enhancing the dissolution and oral absorption of DRN with a simple preparation process.

In vivo wound-healing effects of novel benzalkonium chloride-loaded hydrocolloid wound dressing.

The purpose of this study was to evaluate the wound-healing effects of a novel benzalkonium chloride (BC)-loaded hydrocolloid wound dressing (HCD). A BC-loaded HCD was prepared with various constituents using a hot melting method, and its mechanical properties and antimicrobial activities were assessed. The in vivo wound healings of the BC-loaded HCD in various would models were evaluated in rats compared with a commercial wound dressing, Duoderm™. This BC-loaded HCD gave better skin adhesion, swelling, mechanical strength, and flexibility compared with the commercial wound dressing. It showed excellent antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In addition, as compared with the commercial wound dressing, it showed more improved wound healings and tissue restoration effect on the excision, infection, and abrasion wounds in rats. Thus, this novel BC-loaded HCD would be an excellent alternative to the commercial wound dressing for treatment of various wounds.

Pharmacokinetics of chlorogenic acid and corydaline in DA-9701, a new botanical gastroprokinetic agent, in rats.

1.Few studies describing the pharmacokinetic properties of chlorogenic acid (CA) and corydaline (CRD) which are marker compounds of a new prokinetic botanical agent, DA-9701, have been reported. The aim of the present study is to evaluate the pharmacokinetic properties CA and CRD following intravenous and oral administration of pure CA (1-8 mg/kg) or CRD (1.1-4.5 mg/kg) and their equivalent dose of DA-9701 to rats. 2. Dose-proportional AUC and dose-independent clearance (10.3-12.1 ml/min/kg) of CA were observed following its administration. Oral administration of CA as DA-9701 did not influence the oral pharmacokinetic parameters of CA. Incomplete absorption of CA, its decomposition in the gastrointestinal tract, and/or pre-systemic metabolism resulted in extremely low oral bioavailability (F) of CA (0.478-0.899%). 3. CRD showed greater dose-normalized AUC in the higher dose group than that in lower dose group(s) after its administration due to saturation of its metabolism via decreased non-renal clearance (by 51.3%) and first-pass extraction. As a result, the F of CRD following 4.5 mg/kg oral CRD (21.1%) was considerably greater than those of the lower dose groups (9.10 and 13.8%). However, oral administration of CRD as DA-9701 showed linear pharmacokinetics as a result of increased AUC and F in lower-dose groups (by 182% and 78.5%, respectively) compared to those of pure CRD. The greater oral AUC of CRD for DA-9701 than for pure CRD could be due to decreased hepatic and/or GI first-pass extraction of CRD by other components in DA-9701.

Evaluation of the transporter-mediated herb-drug interaction potential of DA-9801, a standardized dioscorea extract for diabetic neuropathy, in human in vitro and rat in vivo.

BACKGROUND: Drug transporters play important roles in the absorption, distribution, and elimination of drugs and thereby, modulate drug efficacy and toxicity. With a growing use of poly pharmacy, concurrent administration of herbal extracts that modulate transporter activities with drugs can cause serious adverse reactions. Therefore, prediction and evaluation of drug-drug interaction potential is important in the clinic and in the drug development process. DA-9801, comprising a mixed extract of Dioscoreae rhizoma and Dioscorea nipponica Makino, is a new standardized extract currently being evaluated for diabetic peripheral neuropathy in a phase II clinical study. METHOD: The inhibitory effects of DA-9801 on the transport functions of organic cation transporter (OCT)1, OCT2, organic anion transporter (OAT)1, OAT3, organic anion transporting polypeptide (OATP)1B1, OATP1B3, P-glycoprotein (P-gp), and breast cancer resistance protein (BCRP) were investigated in HEK293 or LLC-PK1 cells. The effects of DA-9801 on the pharmacokinetics of relevant substrate drugs of these transporters were also examined in vivo in rats. RESULTS: DA-9801 inhibited the in vitro transport activities of OCT1, OCT2, OAT3, and OATP1B1, with IC50 values of 106, 174, 48.1, and 273 µg/mL, respectively, while the other transporters were not inhibited by 300 µg/mL DA-9801. To investigate whether this inhibitory effect of DA-9801 on OCT1, OCT2, and OAT3 could change the pharmacokinetics of their substrates in vivo, we measured the pharmacokinetics of cimetidine, a substrate for OCT1, OCT2, and OAT3, and of furosemide, a substrate for OAT1 and OAT3, by co-administration of DA-9801 at a single oral dose of 1,000 mg/kg. Pre-dose of DA-9801 5 min or 2 h prior to cimetidine administration decreased the Cmax of cimetidine in rats. However, DA-9801 did not affect the elimination parameters such as half-life, clearance, or amount excreted in the urine, suggesting that it did not inhibit elimination process of cimetidine, which is governed by OCT1, OCT2, and OAT3. Moreover, DA-9801 did not affect the pharmacokinetic characteristics of furosemide, as evidenced by its unchanged pharmacokinetic parameters. CONCLUSION: Inhibitory effects of DA-9801 on OCT1, OCT2, and OAT3 observed in vitro may not necessarily translate into in vivo herb-drug interactions in rats even at its maximum effective dose.

Longan extract suppresses food intake through regulation of POMC/AgRP neuronal activities and endoplasmic reticulum stress in hypothalamus of db/db mice.

Type 2 diabetes mellitus (T2DM) is one of the biggest public health issues worldwide and closely related to development of other chronic diseases such as cardiovascular diseases, cancer and neurodegenerative diseases. Considerable percentage of T2DM patients undergo have suffered from binge eating disorder which exacerbates insulin resistance and metabolic challenges. Longan (Dimocarpus longan L.) and its constituents are reported for their various health benefits. However, it is still unknown whether longan fruit supplementation can ameliorate glucose homeostasis and binge eating disorder found in T2DM. The current study aimed to investigate whether longan fruit extract (LE) supplementation can improve diabetic hyperglycemia through modulation of feeding center located in hypothalamus of db/db T2DM mice. As a result, LE supplementation ameliorated fasting blood glucose levels and reduced excessive epididymal fat accumulation. In addition, LE administration improved glucose tolerance and insulin sensitivity in db/db mice. Especially, LE supplemented mice showed less food consumption which was in line with increase of pro-opiomelanocortin (POMC) neuronal activities and decrease of agouti-related peptide (AgRP) neuronal activities. Furthermore, LE supplementation reduced hypothalamic endoplasmic reticulum (ER) stress which was stimulated in db/db mice. As ER stress is a crucial factor involving in appetite control and glucose homeostasis, the effect of LE supplementation on circulating glucose levels and feeding behavior might be mediated by suppression of hypothalamic ER stress. Collectively, these findings suggest that LE could be a potential nutraceutical for improvement of T2DM as well as patients with satiety issues.

Effects of DA-9701, a novel prokinetic agent, on gastric accommodation in conscious dogs.

BACKGROUND AND AIM: DA-9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, has strong prokinetic effects, and enhances gastric compliance in conscious dogs. In this study, the effects of DA-9701 on gastric accommodation were studied in conscious dogs. METHODS: Beagle dogs with an implanted gastric cannula in the stomach were used in this study. After an overnight fast, the dogs received DA-9701 orally, or served as a positive control that received sumatriptan or a negative control before ingestion of a meal. The basal and postprandial gastric volumes were monitored at a constant operating pressure using an electronic barostat. To investigate the long-lasting effects on increased postprandial gastric volume, the area under the volume versus time curve (AUC) was calculated. RESULTS: DA-9701 significantly increased the basal gastric volume compared to the negative controls (P < 0.05); the effects were comparable to sumatriptan. DA-9701 and sumatriptan significantly increased gastric accommodation compared to the negative control (P < 0.05). In the negative control, the gastric volume reached the maximal volume 40 min after the meal, and then gradually decreased. However, with DA-9701, the increased gastric volume remained significantly elevated for 60 min postprandially (P < 0.05). DA-9701 significantly increased the value of AUC compared to the negative control; this was observed during both the early and late postprandial phases (P < 0.05). CONCLUSIONS: A novel prokinetic agent, DA-9701, improved gastric accommodation by increasing the postprandial gastric volume; these effects persisted for 60 min after a meal.

In vitro metabolism of corydaline in human liver microsomes and hepatocytes using liquid chromatography-ion trap mass spectrometry.

Corydaline is a pharmacologically active isoquinoline alkaloid isolated from Corydalis tubers. It exhibits the antiacetylcholinesterase, antiallergic, antinociceptive, and gastric emptying activities. The purposes of this study were to establish in vitro metabolic pathways of corydaline in human liver microsomes and hepatocytes by identification of their metabolites using liquid chromatography-ion trap mass spectrometry. Human liver microsomal incubation of corydaline in the presence of an NADPH-generating system resulted in the formation of nine metabolites, namely, four O-desmethylcorydaline [M1 (yuanhunine), M2 (9-O-desmethylcorydaline), M3 (isocorybulbine), and M4 (corybulbine)], three di-O-desmethylcorydaline [M5 (9,10-di-O-desmethylcorydaline), M6 (2,10-di-O-desmethylcorydaline), and M7 (3,10-di-O-desmethylcorydaline)], M8 (hydroxyyuanhunine), and M9 (hydroxycorydaline). Incubation of corydaline in human hepatocytes produced four metabolites including M1, M5, M6, and M9. O-Demethylation and hydroxylation were the major metabolic pathways for the metabolism of corydaline in human liver microsomes and hepatocytes.

Effect of a New Prokinetic Agent DA-9701 Formulated with Corydalis Tuber and Pharbitidis Semen on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes.

DA-9701 is a new botanical drug composed of the extracts of Corydalis tuber and Pharbitidis semen, and it is used as an oral therapy for the treatment of functional dyspepsia in Korea. The inhibitory potentials of DA-9701 and its component herbs, Corydalis tuber and Pharbitidis semen, on the activities of seven major human cytochrome P450 (CYP) enzymes and four UDP-glucuronosyltransferase (UGT) enzymes in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. DA-9701 and Corydalis tuber extract slightly inhibited UGT1A1-mediated etoposide glucuronidation, with 50% inhibitory concentration (IC(50)) values of 188 and 290 µg/mL, respectively. DA-9701 inhibited CYP2D6-catalyzed bufuralol 1'-hydroxylation with an inhibition constant (K(i)) value of 6.3 µg/mL in a noncompetitive manner. Corydalis tuber extract competitively inhibited CYP2D6-mediated bufuralol 1'-hydroxylation, with a K(i) value of 3.7 µg/mL, whereas Pharbitidis semen extract showed no inhibition. The volume in which the dose could be diluted to generate an IC(50) equivalent concentration (volume per dose index) value of DA-9701 for inhibition of CYP2D6 activity was 1.16 L/dose, indicating that DA-9701 may not be a potent CYP2D6 inhibitor. Further clinical studies are warranted to evaluate the in vivo extent of the observed in vitro interactions.

Design of Experiments-Based Optimization of Flavonoids Extraction from Daphne genkwa Flower Buds and Flavonoids Contents at Different Blooming Stages.

The flower buds of Daphne genkwa have been reported as a potent resource associated with anti-angiogenic, anti-tumor, anti-rheumatoid arthritis activities, as well as immunoregulation. This paper aimed to establish an optimal extraction method for flavonoids, as active phytochemicals, and to conduct a comparative analysis by profiling the different blooming stages. Optimized shaking extraction conditions from the design of experiments (DoE), such as minutely mixture design, 23 full factorial design, and polynomial regression analysis, involved an agitation speed of 150 rpm and temperature of 65 °C for 12 h in 56% (v/v) acetone solvent. After, a comparative analysis was performed on three blooming stages, juvenile bud, mature purple bud, and complete flowering, by ultra-high-performance liquid chromatography-photodiode array-mass spectrometry (UHPLC-PDA-MS). Most flavonoids increased during bud growth and then decreased when the bud opened for blooming. In particular, apigenin 7-O-glucuronide, genkwanin 5-O-primeveroside, and genkwanin strikingly showcased this pattern. Furthermore, the raw spectrometric dataset was subjected to orthogonal projection to latent structures discriminant analysis (OPLS-DA) to find significant differences in the flavonoids from the juvenile bud, mature purple bud, and complete flowering. In conclusion, the present study facilitates an understanding of flavonoid change at different blooming stages and provides a momentous reference in the research of D. genkwa.

Inhibition of α-synuclein aggregation by MT101-5 is neuroprotective in mouse models of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease, after Alzheimer's disease, and becomes increasingly prevalent with age. α-Synuclein (α-syn) forms the major filamentous component of Lewy bodies, which are pathological hallmarks of α-synucleinopathies such as PD. We evaluated the neuroprotective effects of MT101-5, a standardized herbal formula that consists of an ethanolic extract of Genkwae Flos, Clematidis Radix, and Gastrodiae Rhizoma, against α-synuclein-induced cytotoxicity in vivo. MT101-5 protected against behavioral deficits and loss of dopaminergic neurons in human α-syn-overexpressing transgenic mice after treatment with 30 mg/kg/day for 5 months. We investigated transcriptomic changes within MT101-5 mechanisms of action (MOA) suppressing α-syn aggregation in an α-synuclein preformed fibril (α-syn PFF) mouse model of sporadic PD. We found that inhibition of α-syn fibril formation was associated with changes in transcripts in mitochondrial biogenesis, electron transport, chaperones, and proteasomes following treatment with MT101-5. These results suggest that the mixed herbal formula MT101-5 may be used as a pharmaceutical agent for preventing or improving PD.

Tetrahydroberberine, an isoquinoline alkaloid isolated from corydalis tuber, enhances gastrointestinal motor function.

Because delayed gastric emptying and impaired gastric accommodation are regarded as pathophysiological mechanisms underlying functional dyspepsia (FD), prokinetics and fundic relaxants have been suggested as a new treatment for FD. We isolated tetrahydroberberine (THB), an isoquinoline alkaloid (5,8,13,13a-tetrahydro-9,10-dimethoxy-6H-benzo[g]-1,3-benzodioxolo[5,6-a]quinolizine) from Corydalis tuber, and found that it has micromolar affinity for dopamine D(2) (pK(i) = 6.08) and 5-HT(1A) (pK(i) = 5.38) receptors but moderate to no affinity for other relevant serotonin receptors (i.e., 5-HT(1B), 5-HT(1D), 5-HT(3), and 5-HT(4); pK(i) < 5.00). Oral administration of THB not only resulted in significantly accelerated gastric emptying of normal rats in a bell-shaped relationship, with a maximal efficacy at a dose of 30 µg/kg, but also restored the delayed gastric emptying caused by apomorphine, which might be mediated by an antidopaminergic effect. Data from electromyography indicated enhanced motor function of the upper gastrointestinal tract by THB, which occurred through strengthening contractility and shortening the contraction interval. Furthermore, in rats stressed by repeated restraint, a significantly higher shift in the pressure-volume curve by THB (10 µg/kg, p < 0.05), which was inhibited by [O-methyl-3H]-N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY-100635), a 5-HT(1A) antagonist, and N(ω)-nitro-l-arginine methyl ester, a nitric-oxide synthase inhibitor but not a vasoactive intestinal peptide antagonist, was observed. Oral administration of THB resulted in a drastic increase of gastric accommodation in Beagle dogs. Area under the volume versus time curve was increased significantly by THB (30 µg/kg, p < 0.01) and comparable with that of sumatriptan (3 mg/kg), a potent fundic relaxant. Taken together, our data suggested that THB, with D(2) receptor antagonist and 5-HT(1A) receptor agonist properties, has significant potential as a therapeutic for treatment of FD.

Diosgenin from Dioscorea nipponica ameliorates diabetic neuropathy by inducing nerve growth factor.

Diabetic neuropathy is characterized by axonal degeneration, demyelination, and atrophy in association with failed axonal regeneration, remyelination, and synaptogenesis. Recent reports suggest that reduced levels of nerve growth factor (NGF) may play a significant role in the pathogenesis of diabetic polyneuropathy. In this study, we investigated the regulation of NGF by steroid diosgenin (DG) in a diabetic neuropathy rodent model. We found that DG, the primary spirostane-type steroid in several Dioscorea species, increased NGF levels in the sciatic nerve of diabetic rats. Additionally, DG increased neurite outgrowth in PC12 cells and enhanced nerve conduction velocities in the diabetic neuropathy mouse model. DG-treated diabetic mice showed reduced disarrangement of the myelin sheath and increased area of myelinated axons by electron microscope studies and exhibited improvement in the damaged axons. Our data further suggest that DG increased the nerve conduction velocity through induction of NGF. Thus, our findings indicate that DG, a major sapogenin obtained from Dioscorea nipponica, reverses functional and ultrastructural changes and induces neural regeneration in a diabetic neuropathy model.

Corydaline inhibits multiple cytochrome P450 and UDP-glucuronosyltransferase enzyme activities in human liver microsomes.

Corydaline is a bioactive alkaloid with various antiacetylcholinesterase, antiallergic, and antinociceptive activities found in the medicinal herb Corydalis Tubers. The inhibitory potential of corydaline on the activities of seven major human cytochrome P450 and four UDP-glucuronosyltransferase enzymes in human liver microsomes was investigated using LC-tandem MS. Corydaline was found to inhibit CYP2C19-catalyzed S-mephenytoin-4'-hydroxylatoin and CYP2C9-catalyzed diclofenac 4-hydroxylation, with K(i) values of 1.7 and 7.0 mM, respectively. Corydaline also demonstrated moderate inhibition of UGT1A1-mediated 17b-estradiol 3-glucuronidation and UGT1A9-mediated propofol glucuronidation with K(i) values of 57.6 and 37.3 mM, respectively. In the presence of corydaline, CYP3A-mediated midazolam hydroxylation showed a decrease with increasing preincubation time in a dose-dependent manner with K(i) values of 30.0 mM. These in vitro results suggest that corydaline should be evaluated for potential pharmacokinetic drug interactions in vivo due to potent inhibition of CYP2C19 and CYP2C9.