Traditional Chinese Medicinal Plant Extracts Research Articles

Chemical constituents from Macleaya cordata (Willd) R. Br. and their phenotypic functions against a Parkinson’s disease patient-derived cell line

Cytological profiling (CP) assay against a human olfactory neuroshpere-derived (hONS) cell line using a library of traditional Chinese medicinal plant extracts gave indications that the ethanolic extract of Macleaya cordata (Willd) R. Br. elicited strong perturbations to various cellular components. Further chemical investigation of this extract resulted in the isolation of two new benzo[c]phenanthridine alkaloids, (6R)-10-methoxybocconoline (1) and 6-(1-hydroxyethyl)-10-methoxy-5,6-dihydrochelerythrine (2). Their planar structures were elucidated by extensive 1D and 2D NMR studies, together with MS data. The absolute configuration for position C-6 of 1 and relative configurations for position C-6 and C-1′ of 2 were assigned by density functional theory (DFT) calculations of ECD and NMR data, respectively. Also isolated were fourteen known metabolites, including ten alkaloids (3–12) and four coumaroyl-containing compounds (13–16). Cytological profiling of the isolates against Parkinson’s Disease (PD) patient-derived olfactory cells revealed bocconoline (3) and 6-(1-hydroxyethyl)-5,6-dihydrochelerythrine (4) significantly perturbated the features of cellular organelles including early endosomes, mitochondria and autophagosomes. Given that hONS cells from PD patients model some functional aspects of the disease, the results suggested that these phenotypic profiles may have a role in the mechanisms underlying PD and signified the efficacy of CP in finding potential chemical tools to study the biological pathways in PD.

Large-Scale Screening of 239 Traditional Chinese Medicinal Plant Extracts for Their Antibacterial Activities against Multidrug-Resistant Staphylococcus aureus and Cytotoxic Activities.

Novel alternative antibacterial compounds have been persistently explored from plants as natural sources to overcome antibiotic resistance leading to serious foodborne bacterial illnesses. In this study, the ethanolic extracts from 239 traditional Chinese medicinal plants (TCMP)’ materials were screened to discover promising candidates that have strong antibacterial properties against multidrug-resistant Staphylococcus (S.) aureus and low cytotoxicity. The results revealed that 74 extracts exhibited good antibacterial activities (diameter of inhibition zone (DIZ) ≥ 15 mm). Furthermore, 18 extracts (DIZ ≥ 20 mm) were determined their minimum inhibitory concentrations (MIC) and minimum bactericide concentrations (MBC), ranging from 0.1 to 12.5 mg/mL and 0.78 to 25 mg/mL, respectively. In addition, most of the 18 extracts showed relatively low cytotoxicity (a median lethal concentration (LC50) >100 µg/mL). The 18 extracts were further determined to estimate possible correlation of their phenolic contents with antibacterial activity, and the results did not show any significant correlation. In conclusion, this study selected out some promising antibacterial TCMP extracts with low cytotoxicity, including Rhus chinensis Mill., Ilex rotunda Thunb., Leontice kiangnanensis P.L.Chiu, Oroxylum indicum Vent., Isatis tinctorial L., Terminalia chebula Retz., Acacia catechu (L.f.) Willd., Spatholobus suberectus Dunn, Rabdosia rubescens (Hemsl.) H.Hara, Salvia miltiorrhiza Bunge, Fraxinus fallax Lingelsh, Coptis chinensis Franch., Agrimonia Pilosa Ledeb., and Phellodendron chinense C.K.Schneid.

The NCI library of traditional Chinese medicinal plant extracts – Preliminary assessment of the NCI-60 activity and chemical profiling of selected species

Botanical-based natural products are an important resource for medicinal drug discovery and continue to provide diverse pharmacophores with therapeutic potential against cancer and other human diseases. A prototype Traditional Chinese Medicine (TCM) plant extract library has been established at the US National Cancer Institute, which contains both the organic and aqueous extracts of 132 authenticated medicinal plant species that collectively represent the potential therapeutic contents of most commonly used TCM herbal prescriptions. This library is publicly available in 96- and 384- well plates for high throughput screening across a broad array of biological targets, as well as in larger quantities for isolation of active chemical ingredients. Herein, we present the methodology used to generate the library and the preliminary assessment of the anti-proliferative activity of this crude extract library in NCI-60 human cancer cell lines screen. Particularly, we report the chemical profiling and metabolome comparison analysis of four commonly used TCM plants, namely Brucea javanica, Dioscorea nipponica, Cynanchum atratum, and Salvia miltiorrhiza. Bioassay-guided isolation resulted in the identification of the active compounds, and different extraction methods were compared for their abilities to extract cytotoxic compounds and to concentrate biologically active natural products.

Evaluation of selected traditional Chinese medical extracts for bone mineral density maintenance: A mechanistic study

ObjectiveTo investigate the development of a minimal traditional Chinese medicine (TCM) formula using selected TCM ingredients and evaluating their biological activity with bone-specific in vitro tests. Finally, determining if the minimal formula can maintain bone mineral density (BMD) in a low bone mass (LBM)/osteoporosis (OP) model system. Methods and resultsSixteen different TCM plant extracts were tested for estrogenic, osteogenic and osteoclastic activities. Despite robust activation of the full-length estrogen receptors α and β by Psoralea corylifolia and Epimedium brevicornu, these extracts do not activate the isolated estrogen ligand binding domains (LBD) of either ERα or ERβ; estrogen (17-β estradiol) fully activates the LBD of ERα and ERβ. E. brevicornu and Drynaria fortunei extracts activated cyclic AMP response elements (CRE) individually and when combined these ingredients stimulated the production of osteoblastic markers Runx2 and Bmp4 in MC3T3-E1 cells. E. brevicornu, Salvia miltiorrhiza, and Astragalus onobrychis extracts inhibited the Il-1β mediated activation of NF-κβ and an E. brevicornu/D. fortunei combination inhibited the development of osteoclasts from precursor cells. Further, a minimal formula containing the E. brevicornu/D. fortunei combination with or without a third ingredient (S. miltiorrhiza, Angelica sinensis, or Lycium barbarum) maintained bone mineral density (BMD) similar to an estradiol-treated control group in the ovariectomized rat; a model LBM/OP system. ConclusionA minimal formula consisting of TCM plant extracts that activate CRE and inhibit of NF-κβ activation, but do not behave like estrogen, maintain BMD in a LBM/OP model system.

Expression and functional activity of bitter taste receptors in primary renal tubular epithelial cells and M-1 cells.

The kidney is essential in the maintenance of in vivo homeostasis by body fluid and electrolyte conservation and metabolic waste removal. Previously, we reported the expression of a novel G protein family (Tas2rs), which includes bitter taste receptors, in the kidney tubule system, including the nephrons and the collecting duct system. Bitter taste receptors could affect kidney function via Ca2+ intake. Alkaloids such as phenylthiocarbamide stimulate these receptors and cause an increase in Ca2+ intake. In this study, we determined the expression of bitter taste receptors in the immature kidney and small intestine and in primary renal epithelial cells and M-1 (collecting tubule cell line) cells, by using QPCR and immunostaining. We found no expression of bitter taste receptors in the immature kidney and small intestine several days after birth; the relative abundance of Tas2rs transcripts varied depending on the developmental stage. Tas2rs were expressed in primary renal epithelial cells and M-1 cells. The traditional Chinese medicinal plant extracts phellodendrine and coptisine caused a rapid rise in intracellular Ca2+ concentration, which was inhibited by the phospholipase C (PLC) inhibitor U-73122. Thus, phellodendrine and coptisine could change the physiological status of renal cells in vitro by mediation of bitter taste receptors in a PLC-dependent manner. Our results provide new insights on the expression and role of bitter taste receptors in renal development and function.

The efficacy of four common anthelmintic drugs and traditional Chinese medicinal plant extracts to control Dactylogyrus vastator (Monogenea)

Disease caused by Dactylogyrus vastator has resulted in considerable economic damage in aquaculture. To control this parasite effectively, the anthelmintic properties of several extracts obtained from Euphorbia fischeriana and four common anthelmintic drugs (trichlorfon, praziquantel, 40% phoxim and mebendazole) against adults and eggs of D. vastator were assessed in vitro and in vivo. Trichlorfon (0.5, 1 and 1.5mg/L), praziquantel (10 and 20mg/L), 40% phoxim (0.1, 0.2 and 0.4mg/L), mebendazole (0.02 and 0.04mg/L) and the ethyl acetate extract of E. fischeriana (10 and 20mg/L) were effective to kill the parasites in vitro, while the other extracts (petroleum ether, n-butanol and distilled water) of E. fischeriana had no significant effects. Praziquantel effectively killed adults with the efficacy of 80.3% at 20mg/L and inhibited egg hatching, while trichlorfon and the ethyl acetate extract of E. fischeriana effectively eliminated adult parasites with the efficacy of 87.3% and 80.1% at 2.5mg/L and 14mg/L, but had no effect on egg viability. 40% phoxim was highly effective in suppressing egg hatching, but mebendazole was not significantly effective on either adults or eggs. Overall, this study found that 40% phoxim and praziquantel could prevent horizontal infection via eggs in aquaculture facilities and that trichlorfon, praziquantel and the ethyl acetate extract of E. fischeriana could be effective against adult parasites. However, the effective dose of the ethyl acetate extract of E. fischeriana was very close to the toxic dose, a factor that likely limits its practical application in aquaculture.

Hypoxia affects cellular responses to plant extracts

Ethnopharmacological relevanceMicroenvironmental conditions contribute towards varying cellular responses to plant extract treatments. Hypoxic cancer cells are known to be resistant to radio- and chemo-therapy. New therapeutic strategies specifically targeting these cells are needed. Plant extracts used in Traditional Chinese Medicine (TCM) can offer promising candidates. Despite their widespread usage, information on their effects in hypoxic conditions is still lacking. In this study, we examined the cytotoxicity of a series of known TCM plant extracts under normoxic versus hypoxic conditions. Materials and methodsPereskia grandifolia, Orthosiphon aristatus, Melastoma malabathricum, Carica papaya, Strobilanthes crispus, Gynura procumbens, Hydrocotyle sibthorpioides, Pereskia bleo and Clinacanthus nutans leaves were dried, blended into powder form, extracted in methanol and evaporated to produce crude extracts. Human Saos-2 osteosarcoma cells were treated with various concentrations of the plant extracts under normoxia or hypoxia (0.5% oxygen). 24h after treatment, an MTT assay was performed and the IC50 values were calculated. Effect of the extracts on hypoxia inducible factor (HIF) activity was evaluated using a hypoxia-driven firefly luciferase reporter assay. ResultsThe relative cytotoxicity of each plant extract on Saos-2 cells was different in hypoxic versus normoxic conditions. Hypoxia increased the IC50 values for Pereskia grandifola and Orthosiphon aristatus extracts, but decreased the IC50 values for Melastoma malabathricum and Carica papaya extracts. Extracts of Strobilanthes crispus, Gynura procumbens, Hydrocotyle sibthorpioides had equivalent cytotoxic effects under both conditions. Pereskia bleo and Clinacanthus nutans extracts were not toxic to cells within the concentration ranges tested. The most interesting result was noted for the Carica papaya extract, where its IC50 in hypoxia was reduced by 3-fold when compared to the normoxic condition. This reduction was found to be associated with HIF inhibition. ConclusionHypoxia variably alters the cytotoxic effects of TCM plant extracts on cancer cells. Carica papaya showed enhanced cytotoxic effect on hypoxic cancer cells by inhibiting HIF activities. These findings provide a plausible approach to killing hypoxic cancer cells in solid tumors.

Baicalin, a prodrug able to reach the CNS, is a prolyl oligopeptidase inhibitor

Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyzes proline-containing peptides at the carboxy terminus of proline residues. It has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders and therefore may have important clinical implications. In a previous work, we used 19F NMR to search for new prolyl oligopeptidase inhibitors from a library of traditional Chinese medicine plant extracts, and identified several extracts as powerful inhibitors of this peptidase. Here, the flavonoid baicalin was isolated as the active component of an extract of Scutellaria baicalensis roots having prolyl oligopeptidase inhibitory activity. Baicalin inhibited prolyl oligopeptidase in a dose-dependent manner. Inhibition experiments using baicalin analogs showed that the sugar moiety was not necessary for activity. The IC 50s of baicalin and its aglycone derivative baicalein were rather similar, showing that the sugar moiety was not involved in the interaction of baicalin with POP. These results were confirmed by saturation transfer difference NMR experiments. To further understand the absorption and transport mechanisms of baicalin and baicalein, we evaluated their transport in vitro through the gastrointestinal tract and the blood–brain barrier using a Parallel Artificial Membrane Permeability Assay. The molecule which potentially crosses both barriers was identified as baicalein, the aglycone moiety of baicalin. Our results show that baicalin is a new prodrug able to inhibit prolyl oligopeptidase. As baicalin is a natural compound with a long history of safe administration to humans, it is a highly attractive base from which to develop new treatments for schizophrenia, bipolar affective disorder, and related neuropsychiatric diseases.

The Natural Product Berberine is a Human Prolyl Oligopeptidase Inhibitor

Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyzes proline-containing peptides at the carboxy terminus. This peptidase has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders, and therefore may have important clinical implications. Among the strategies used to find novel prolyl oligopeptidase inhibitors, traditional Chinese medicinal plants provide a rich source of unexplored compounds. We used (19)F NMR spectroscopy to search for new prolyl oligopeptidase inhibitors in a library of traditional Chinese medicine plant extracts. Several extracts were identified as powerful inhibitors of this peptidase. The alkaloid berberine was the prolyl oligopeptidase inhibitory molecule isolated from Rhizoma coptidis extract. Berberine inhibited prolyl oligopeptidase in a dose-dependent manner. As berberine is a natural compound that has been safely administered to humans, it opens up new perspectives for the treatment of neuropsychiatric diseases. The results described herein suggest that the initiation of clinical trials in patients with schizophrenia, bipolar affective disorder, or related diseases in which cognitive capabilities are affected should be undertaken with either the extract or pure BBR.

Identification by 19F NMR of Traditional Chinese Medicinal Plants Possessing Prolyl Oligopeptidase Inhibitory Activity

Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyzes proline-containing peptides at the carboxy termini of the proline residues. This peptidase has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders and might therefore have important clinical implications. Traditional Chinese medicinal (TCM) plants provide a rich source of unexplored compounds for strategies to find novel POP inhibitors, but the traditional methodologies used to identify POP inhibitors could have some limitations when working with natural products: interference with the colorimetric or fluorimetric detection methods commonly used to screen for POP inhibitors can result in the generation of false positives or false negatives. Since NMR screening is less prone to such interference, we decided to explore the use of 19F NMR to screen for POP inhibitors. We synthesized a new 19F-labeled POP substrate--Z-Gly-Pro-Phe-4(CF3)-NH2--and used it to search for new POP inhibitors in TCM plant extracts. We identified several plants with high POP-inhibitory activity and show here that the combination of 19F NMR and TCM plant extracts is a useful tool for identifying new POP inhibitors.