First-in-Class Dual EZH2-HSP90 Inhibitor Eliciting Striking Antiglioblastoma Activity In Vitro and In Vivo

Structural analysis of tazemetostat, an FDA-approved EZH2 inhibitor, led us to pinpoint a suitable site for appendage with a pharmacophoric fragment of second-generation HSP90 inhibitors. Resultantly, a magnificent dual EZH2/HSP90 inhibitor was pinpointed that exerted striking cell growth inhibitory efficacy against TMZ-resistant Glioblastoma (GBM) cell lines. Exhaustive explorations of chemical probe 7 led to several revelations such as (i) compound 7 increased apoptosis/necrosis-related gene expression, whereas decreased M phase/kinetochore/spindle-related gene expression as well as CENPs protein expression in Pt3R cells; (ii) dual inhibitor 7 induced cell cycle arrest at the M phase; (iii) compound 7 suppressed reactive oxygen species (ROS) catabolism pathway, causing the death of TMZ-resistant GBM cells; and (iv) compound 7 elicited substantial in vivo anti-GBM efficacy in experimental mice xenografted with TMZ-resistant Pt3R cells. Collectively, the study results confirm the potential of dual EZH2-HSP90 inhibitor 7 as a tractable anti-GBM agent.

NCI677397 targeting USP24-mediated induction of lipid peroxidation induces ferroptosis in drug-resistant cancer cells

Cancer represents a profound challenge to healthcare systems and individuals worldwide. The development of multiple drug resistance is a major problem in cancer therapy and can result in progression of the disease. In our previous studies, we developed small-molecule inhibitors targeting ubiquitin-specific peptidase 24 (USP24) to combat drug-resistant lung cancer. Recently, we found that the USP24 inhibitor NCI677397 induced ferroptosis, a type of programmed cell death, in drug-resistant cancer cells by increasing lipid reactive oxygen species (ROS) levels. In the present study, we investigated the molecular mechanisms and found that the targeting of USP24 by NCI677397 increased gene expression of most lipogenesis-related genes, such as acyl-CoA synthetase long-chain family member 4 (ACSL4), and activated autophagy. In addition, the activity of several antioxidant enzymes, such as glutathione peroxidase 4 (GPX4) and dihydrofolate reductase (DHFR), was inhibited by NCI677397 treatment via an increase in protein degradation, thereby inducing lipid ROS production and lipid peroxidation. In summary, we demonstrated that NCI677397 induced a marked increase in lipid ROS levels, subsequently causing lipid peroxidation and leading to the ferroptotic death of drug-resistant cancer cells. Our study provides new insights into the clinical use of USP24 inhibitors as ferroptosis inducers (FINs) to block drug resistance during chemotherapy.

ADP-mimicking Platelet Aggregation Caused by Rugosin E, an Ellagitannin Isolated from Rosa rugosa Thunb

Among the nine ellagitannins, rugosin E was the most potent platelet aggregating agent with an EC50 of 1.5 ± 0.1 µM in rabbit platelets and 3.2 ±0.1 µM in human platelets. The aggregations caused by rugosin E and ADP were inhibited by EGTA, PGE1, mepacrine, sodium nitroprusside and neomycin, but not by indomethacin, verapamil, TMB-8, BN52021 and GR32191B. Rugosin E-induced thromboxane formation was suppressed by indomethacin, EGTA, PGE,, verapamil, mepacrine, TMB-8 and neomycin. ADP-scavenging agents, such as CP/CPK and apyrase inhibited concentration-dependently ADP (20 εM)-, but not rugosin E (5 εM)-induced platelet aggregation. In thrombin (0.1 U/ml)-treated and degranulated platelets, rugosin E and ADP still caused 63.5 ± 3.0% and 61.2 ± 3.5% of platelet aggregation, respectively. Selective ADP receptor antagonists, ATP and FSBA inhibited rugosin E- and ADP-induced platelet aggregations in a concentration-dependent manner. Both rugosin E and ADP did not induce platelet aggregation in ADP (1 mM)-desensitized platelets. In contrast to ADP, rugosin E did not decrease cAMP formation in washed rabbit platelets. Both rugosin E and ADP did not cause phosphoinositide breakdown in [3H]myo-inositol-labeled rabbit platelets. In fura-2/AM- load platelets, both rugosin E and ADP induced increase in intracellular calcium concentration and these responses were inhibited by ATP and PGEj. All these data suggest that rugosin E may be an ADP receptor agonist in rabbit platelets.

Evaluation of Xanthine Oxidase Inhibitory Potential and In vivo Hypouricemic Activity of Dimocarpus longan Lour. Extracts

BACKGROUND

Longan is a fruit tree known to contain many phenolic components, which are capable of protecting people from oxidative damage through an anti-inflammatory mechanism. It may be also worthwhile to study the effect on lowering uric acid activity.

MATERIALS AND METHODS

This study investigates the lowering of uric acid using longan extracts, including flowers, pericarps, seeds, leaves, and twigs, on potassium-oxonate-induced hyperuricemia mice and its inhibitory actions against xanthine oxidase (XO) activities.

RESULTS

The findings revealed that ethyl acetate fraction of longan extracts exhibited strong XO-inhibitory activity, and the flower extracts (IC50 = 115.8 μg/mL) revealed more potent XO-inhibitory activity to those of pericarps (118.9 μg/mL), twigs (125.3 μg/mL), seeds (262.5 μg/mL), and leaves (331.1 μg/mL) in vitro. In addition, different dosages of longan extract (50-100 mg/kg) were administered to hyperuricemic mice. The lowering effect of longan extracts on uric acid at 75 mg/kg markedly reduced plasma uric acid levels in decreasing order: Flowers (80%) > seeds (72%) > pericarps (64%) > twigs (59%) > leaves (41%), compared with allopurinol (89%). Finally, 10 isolated phytochemicals from longan flowers were then examined in vitro. The results indicated that proanthocyanidin A2 and acetonylgeraniin A significantly inhibited XO activity in vitro. This is the first report providing new insights into the urate-reducing effect of phenolic dimer and hydrolyzable tannin, which can be developed to potential hypouricemic agents.

SUMMARY

Longan flower extracts possess more potent XO-inhibitory activity than pericarps, twigs, seeds, and leaves in vitroThe lowering effect of longan flowers and seeds extracts markedly reduced plasma uric acid levels as compared to allopurinol in vivoThe extract proanthocyanidin A2 and acetonylgeraniin A were demonstrated potent XO inhibitory activity in vitro Abbreviations used: PO: Potassium-oxonate, XO: xanthine oxidase, HE: n-hexane, EA: ethyl acetate, i.p.: intraperitoneal, PBS: phosphate-buffered saline, AP: allopurinol, PUA: plasma uric acid.

Chemical constituents analysis and antidiabetic activity validation of four fern species from Taiwan

Pterosins are abundant in ferns, and pterosin A was considered a novel activator of adenosine monophosphate-activated protein kinase, which is crucial for regulating blood glucose homeostasis. However, the distribution of pterosins in different species of ferns from various places in Taiwan is currently unclear. To address this question, the distribution of pterosins, glucose-uptake efficiency, and protective effects of pterosin A on β-cells were examined. Our results showed that three novel compounds, 13-chloro-spelosin 3-O-β-d-glucopyranoside (1), (3R)-Pterosin D 3-O-β-d-(3'-p-coumaroyl)-glucopyranoside (2), and (2R,3R)-Pterosin L 3-O-β-d-(3'-p-coumaroyl)-glucopyranoside (3), were isolated for the first time from four fern species (Ceratopteris thalictroides, Hypolepis punctata, Nephrolepis multiflora, and Pteridium revolutum) along with 27 known compounds. We also examined the distribution of these pterosin compounds in the mentioned fern species (except N. multiflora). Although all pterosin analogs exhibited the same effects in glucose uptake assays, pterosin A prevented cell death and reduced reactive oxygen species (ROS) production. This paper is the first report to provide new insights into the distribution of pterosins in ferns from Taiwan. The potential anti-diabetic activity of these novel phytocompounds warrants further functional studies.

5β,19-epoxycucurbitane triterpenoids from Momordica charantia and their anti-inflammatory and cytotoxic activity

Five new 5β,19-epoxycucurbitane triterpenoids, taikugausins A-E (1-5), together with 5β,19-epoxy-25-methoxycucurbita-6,23-diene-3β,19-diol (6), have been isolated and characterized from the 70 % EtOH extract of the fresh fruits of Momordica charantia. The chemical structures of compounds 1-6 were elucidated on the basis of extensive spectroscopic analyses, especially 2D NMR (HMQC, HMBC, and NOESY) experiments and HRESIMS data. The relationship between NMR chemical shifts and the configuration of C-19 with an OMe group in 5β,19-epoxycucurbitane are described. Among them, compounds 3 and 4 exhibited remarkable anti-inflammatory activities by the inhibition of nitric oxide production at the concentration of 10 µg/mL. In addition, 3 and 4 also showed moderate cytotoxicity against WiDr, Hep G2, MCF-7, and HEp-2 human tumor cell lines.

Ethosomes in hair dye products as carriers of the major compounds of black tea extracts

OBJECTIVES

This study describes a novel carrier, the ethosome-based system, which is composed of non-ionic surfactants, ethanol, and water.

METHODS

Brij(®) 52 (non-ionic surfactants), soya phosphatidylcholine (PC), cholesterol, and the major compounds (caffeine and gallic acid) of black tea extracts were dissolved in the ethanolic phase. The aqueous phase containing Paragon III was heated to 60 °C and mixed with the previous solution. Finally, 3.4 ml NaOH (6.5 N) was added to adjust the pH level to 4.05. The mixture was centrifuged at 2000 g for two minutes, and the precipitate was taken as the end product. Black tea extracts were applied in ethosome-based formulations, and the efficacy of these formulations in penetrating nude mouse skin and in dyeing white hairs was investigated.

RESULTS

Compared with an ethanolic solution and black tea extracts, the non-ionic ethosomal delivery system dramatically enhanced the adsorption of black tea extracts onto hair surfaces in vitro. The non-ionic ethosomal system was much more efficient in delivering and facilitating the adsorption of black tea extracts to the hair surface than hydroalcoholic black tea extracts.

CONCLUSIONS

This formulation may have potential for development as a hair dye and protective agent.

Antiproliferative and hypoglycemic cucurbitane-type glycosides from the fruits of Momordica charantia

This paper reports that bioassay-guided fractionations of EtOH extract of Momordica charantia fruits led to the isolation of 15 cucurbitane-type triterpene glycosides including 4 new compounds, kuguaosides A-D (1-4), along with 11 known ones, charantoside A (5), momordicosides I (6), F1 (7), F2 (8), K (9), L (10), and U (11), goyaglycosides-b (12) and -d (13), 7β,25-dihydroxycucurbita-5,23(E)-dien-19-al 3-O-β-d-allopyranoside (14), and 25-hydroxy-5β,19-epoxycucurbita-6,23-dien-19-on-3β-ol 3-O-β-d-glucopyranoside (15). Their structures were elucidated on the basis of spectroscopic analyses and chemical methods. This study also established the HPLC-ELSD fingerprinting profile of an antiproliferative fraction of which 11 main peaks were identified. Biological evaluation showed that several isolated cucurbitane-type triterpene glycosides had antiproliferative activities against MCF-7, WiDr, HEp-2, and Doay human tumor cell lines. In addition, compound 14 showed potent hypoglycemic activities by glucose uptake assay.

Antidiabetic effects of pterosin A, a small-molecular-weight natural product, on diabetic mouse models

The therapeutic effect of pterosin A, a small-molecular-weight natural product, on diabetes was investigated. Pterosin A, administered orally for 4 weeks, effectively improved hyperglycemia and glucose intolerance in streptozotocin, high-fat diet-fed, and db/db diabetic mice. There were no adverse effects in normal or diabetic mice treated with pterosin A for 4 weeks. Pterosin A significantly reversed the increased serum insulin and insulin resistance (IR) in dexamethasone-IR mice and in db/db mice. Pterosin A significantly reversed the reduced muscle GLUT-4 translocation and the increased liver phosphoenolpyruvate carboxyl kinase (PEPCK) expression in diabetic mice. Pterosin A also significantly reversed the decreased phosphorylations of AMP-activated protein kinase (AMPK) and Akt in muscles of diabetic mice. The decreased AMPK phosphorylation and increased p38 phosphorylation in livers of db/db mice were effectively reversed by pterosin A. Pterosin A enhanced glucose uptake and AMPK phosphorylation in cultured human muscle cells. In cultured liver cells, pterosin A inhibited inducer-enhanced PEPCK expression, triggered the phosphorylations of AMPK, acetyl CoA carboxylase, and glycogen synthase kinase-3, decreased glycogen synthase phosphorylation, and increased the intracellular glycogen level. These findings indicate that pterosin A may be a potential therapeutic option for diabetes.

Evaluation of antioxidant and free radical scavenging capacities of polyphenolics from pods of Caesalpinia pulcherrima

Thirteen polyphenolics were isolated from fresh pods of Caesalpinia pulcherrima using various methods of column chromatography. The structures of these polyphenolics were elucidated as gallic acid (1), methyl gallate (2), 6-O-galloyl-d-glucoside (3), methyl 6-O-galloyl-β-d-glucoside (4), methyl 3,6-di-O-galloyl-α-d-glucopyranoside (5), gentisic acid 5-O-α-d-(6'-O-galloyl)glucopyranoside (6), guaiacylglycerol 4-O-β-d-(6'-O-galloyl)glucopyranoside (7), 3-methoxy-4-hydroxyphenol 1-O-β-d-(6'-O-galloyl) glucopyranoside (8), (+)-gallocatechin (9), (+)-catechin (10), (+)-gallocatechin 3-O-gallate (11), myricetin 3-rhamnoside (12), and ampelopsin (13). All isolated compounds were tested for their antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and peroxynitrite radicals scavenging assays. Among those compounds, 11, 12, and 2 exhibited the best DPPH-, hydroxyl-, and peroxynitrite radical-scavenging activities, respectively. Compound 7 is a new compound, and possesses better scavenging activities towards DPPH but has equivalent hydroxyl radical scavenging activity when compared to BHT. The paper is the first report on free radical scavenging properties of components of the fresh pods of Caesalpinia pulcherrima. The results obtained from the current study indicate that the free radical scavenging property of fresh pods of Caesalpinia pulcherrima may be one of the mechanisms by which this herbal medicine is effective in several free radical mediated diseases.

Tanshinone IIA attenuates cyclic strain-induced endothelin-1 expression in human umbilical vein endothelial cells

1. Tanshinone IIA, one of the active components of the Radix of Salvia miltiorrhiza, is used in traditional Chinese medicine to treat cardiovascular diseases. However, the intracellular mechanism of action of tanshinone IIA remain to be determined. The aims of the present study were to test the hypothesis that tanshinone IIA alters strain-induced endothelin (ET)-1 expression and nitric oxide (NO) production, as well as to identify the putative signalling pathways involved, in human umbilical vein endothelial cells (HUVEC). 2. Cultured HUVEC were exposed to cyclic strain in the presence of 1-10 μmol/L tanshinone IIA. Expression of ET-1 was examined by reverse transcription-polymerase chain reaction and ELISA. Phosphorylation of endothelial NO synthase (eNOS) and activating transcription factor (ATF) 3 was assessed by western blot analysis. 3. Tanshinone IIA (3 and 10 μmol/L) inhibited strain-induced ET-1 expression. In contrast, NO production, eNOS phosphorylation and ATF3 expression were enhanced by tanshinone IIA. The eNOS inhibitor N(G) -nitro-L-arginine methyl ester (l-NAME; 100 μmol/L), the phosphatidylinositol 3-kinase inhibitor LY294002 (5 μmol/L) and the soluble guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ; 10 μmol/L) inhibited tanshinone IIA-induced increases in ATF3 expression. Moreover, treatment of HUVEC with either an NO donor (3,3-bis [aminoethyl]-1-hydroxy-2-oxo-1-triazene; 500 μmol/L) or an ATF3 activator (carbobenzoxy-L-leucyl-L-leucyl-L-leucinal; 5 μmol/L) resulted in the repression of strain-induced ET-1 expression. The inhibitory effect of tanshinone IIA on strain-induced ET-1 expression was significantly attenuated by l-NAME, ODQ and the transfection of small interfering RNA for ATF3. 4. In conclusion, tanshinone IIA inhibits strain-induced ET-1 expression by increasing NO and upregulating ATF3 in HUVEC. The present study provides important new insights into the molecular pathways that may contribute to the beneficial effects of tanshinone IIA in the cardiovascular system.

Transformation of isosteviol lactam by fungi and the suppressive effects of its transformed products on LPS-induced iNOS expression in macrophages

From the screening of 21 microbial strains, Absidia pseudocylindrospora ATCC 24169 and Aspergillus niger BCRC 32720 were found to reproducibly transform isosteviol lactam (4α-carboxy-13α-amino-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactam) (3) into various compounds. Preparative-scale transformation of 3 with Abs. pseudocylindrospora yielded two new hydroxylated compounds (4 and 5), with conservation of the lactam ring. Preparative-scale transformation of 3 with Asp. niger afforded seven new compounds, 6 and 9-14, together with the known compounds 7 and 8. A single-crystal X-ray diffraction experiment confirmed the structure of 14. The suppressive effects of compounds 1-14 on the lipopolysaccharide-induced expression of the inducible nitric oxide synthase gene in RAW 264.7 macrophages were examined by a reverse-transcription real-time PCR analysis. With the exception of 7, all other compounds significantly reduced levels of iNOS mRNA relative to control cells, which were induced by LPS alone. Compounds 2, 3, and 5 were similar in activity to dexamethasone, while 9 was more potent.

Neurocytoprotective effects of the bioactive constituents of Pueraria thomsonii in 6-hydroxydopamine (6-OHDA)-treated nerve growth factor (NGF)-differentiated PC12 cells

Chronic neurodegenerative disorders are having an increasing impact on public health as human longevity increases. Parkinson's disease (PD) is a degenerative disorder of the central nervous system and is characterized by motor system disorders resulting in loss of dopamine-producing brain cells. Pueraria thomsonii Benth. (Fabaceae) is an herbal medicine that has traditionally been used as an antipyretic agent. In the present study, the active constituents, daidzein and genistein, were isolated from P. thomsonii. Both compounds exhibited neurocytoprotective effects against 6-hydroxydopamine (6-OHDA)-induced cytotoxicity in nerve growth factor (NGF)-differentiated PC12 cells. Neither daidzein nor genistein affected 6-OHDA-induced cellular reactive oxygen species (ROS) generation according to flow cytometric analysis. Rather, they inhibited caspase-8 and partially inhibited caspase-3 activation, providing a protective mechanism against 6-OHDA-induced cytotoxicity in NGF-differentiated PC12 cells. The present results imply that daidzein and genistein may be useful in the development of future strategies for the treatment of PD.

Human monoclonal antibody GNX-8 directed to extended type 1 chain: Specific binding to human colorectal cancer

We observed previously that two carbohydrate epitopes, extended type 1 chain Le(a)-Le(a) and Le(b)-Le(a), are expressed strongly in human gastric or colorectal cancer and cell lines derived therefrom, but their expression in human normal colorectal cells is highly limited. A monoclonal antibody, termed GNX-8, was established through immunization of "KM mice" with colonic cancer cell line Colo205, and with purified Le(b)-Le(a) glycosphingolipid, followed by screening human IgG directed to this antigen. KM mice possess human chromosome fragments and are capable of producing human immunoglobulin. GNX-8 reacted specifically with extended type 1 chain epitope Le(b)-Le(a), bound to all five colonic cancer cell lines so far tested, and displayed strong complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). The antigens defined by GNX-8, expressed in Colo205 cells, were: (i) glycosphingolipids with epitope Le(b)-Le(a), whose reactivity was abolished upon defucosylation; (ii) glycoproteins with molecular mass range from 32 to >175 kDa, which were depleted in cells cultured in the presence of benzyl-alpha-GalNAc, indicating that these epitopes are O-linked glycans.Immunohistological reactivity of GNX-8 at 1 mug/ml, applied on tissue sections from colorectal and various other types of cancer, was much stronger than that with various normal cells and tissues. GNX-8 reactivity with normal cells required a much higher concentration (150 mug/ml), and this reactivity was based on cross-reaction with non-extended, normal blood group Le(b) antigen. Growth of subcutaneous xenograft of human colonic cancer cells, Colo205 or DLD-1, in nude mice or SCID mice, was strongly inhibited by administration of GNX-8. These observations, taken together, indicate that antibody GNX-8, directed specifically to Le(b)-Le(a) antigen, provides a novel direction of immunotherapy for human colorectal cancer. (c) 2009 UICC.

Microbial transformation of isosteviol oxime and the inhibitory effects on NF-kappaB and AP-1 activation in LPS-stimulated macrophages

Microbial transformation of isosteviol oxime (ent-16-E-hydroxyiminobeyeran-19-oic acid) (2) with Aspergillus niger BCRC 32720 and Absidia pseudocylindrospora ATCC 24169 yielded several compounds. In addition to bioconverting the d-ring to lactone and lactam moieties, 4alpha-carboxy-13alpha-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone (7) and 4alpha-carboxy-13alpha-amino-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactam (10), one known compound, ent-1beta,7alpha-dihydroxy-16-oxo-beyeran-19-oic acid (6), and five new compounds, ent-7alpha-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (3), ent-1beta,7alpha-dihydroxy-16-E-hydroxyiminobeyeran-19-oic acid (4), ent-1beta-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (5), ent-8beta-cyanomethyl-13-methyl-12-podocarpen-19-oic acid (8), and ent-8beta-cyanomethyl-13-methyl-13-podocarpen-19-oic acid (9), were isolated from the microbial transformation of 2. Elucidation of the structures of these isolated compounds was primarily based on 1D and 2D NMR, and HRESIMS data, and 3-5 were further confirmed by X-ray crystallographic analyses. Additionally, the inhibitory effects of all of these compounds were evaluated on NF-kappaB and AP-1 activation in LPS-stimulated RAW 264.7 macrophages. Among the compounds tested, 5 and 10 significantly inhibited NF-kappaB activation, with 5 showing equal potency to dexamethasone; 3 and 6-9 significantly inhibited AP-1 activation, particularly 8, which showed more inhibitory activity than dexamethasone.

Fungal transformation of isosteviol lactone and its biological evaluation for inhibiting the AP-1 transcription factor

A number of hydroxylated diterpenoids were obtained from the microbial transformation of isosteviol lactone (4alpha-carboxy-13alpha-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone) (2) with Mucorrecurvatus MR 36, Aspergillusniger BCRC 31130, and Absidiapseudocylindrospora ATCC 24169. Incubation of 2 with M. recurvatus and Asp.niger led to isolation of seven known compounds (1 and 3-8). Incubation of 2 with Abs. pseudocylindrospora produced 5 and six previously unreported compounds (9-14). The structures of these isolated compounds were deduced by high-field NMR techniques ((1)H, (13)C, DEPT, COSY, NOESY, HSQC, and HMBC), and those of 9 and 11 were further confirmed by X-ray crystallographic analyses. Subsequently, the inhibitory effects on activator protein-1 (AP-1) activation in lipopolysaccharide-stimulated RAW 264.7 macrophages of all of these compounds were evaluated. Compounds 2-5, 8, 9, 11, and 12 exhibited significant inhibitory activity, while 3 was more potent than the reference compound of dexamethasone.

Microbial transformation of isosteviol lactone and evaluation of the transformation products on androgen response element

Two filamentous fungi, Cunninghamella bainieri ATCC 9244 and Aspergillus niger BCRC 32720, were used to investigate the biotransformation of isosteviol lactone (4alpha-carboxy-13alpha-hydroxy-13,16- seco-ent-19-norbeyeran-16-oic acid 13,16-lactone) ( 2), which was derived by reacting isosteviol ( ent-16-oxobeyeran-19-oic acid) ( 1) with m-chloroperbenzoic acid. Incubation of 2 with C. bainieri afforded metabolites 3- 6, which involved isomerization, hydroxylation, and ring cleavage reactions followed by oxidation and selective O-methylation. Incubation of 2 with A. niger afforded mono-, di-, and trihydroxylated metabolites 3, 4, and 7- 12. The structures of 3- 12 were elucidated on the basis of spectroscopic analyses, and structures 3, 4, and 6 were confirmed by X-ray crystallographic studies. Compounds 2- 6, 8- 10, and 12 were assayed as androgen agonists using an ARE (androgen response element)-mediated luciferase reporter gene assay. Compounds 3, 6, and 10 were significantly active, with 6 showing more activity than testosterone.

Anemonin is a natural bioactive compound that can regulate tyrosinase-related proteins and mRNA in human melanocytes

BACKGROUND

Melanin is the pigment responsible for skin color. Melanin synthesis occurs with the participation of the tyrosinase (TYR) family of proteins including TYR, tyrosinase-related protein 1 (TRP1), and tyrosinase-related protein 2(TRP2/DCT).

OBJECTIVE

The effect of a newly isolated natural compound that inhibits hyperpigmentation on the regulation of the TYR family of proteins was examined.

METHODS

The natural compound, anemonin, was isolated from Clematis crassifolia Benth and was used to inhibit cellular TYR activity; it was found to have a low cytotoxicity (cell viability > 80%) in human melanocytes.

RESULTS

In human melanocytes, anemonin showed both time- and dose-dependent inhibition (IC(50) 43.5 microM) of TYR. Western blot analysis and immunocytochemical staining revealed that expression of TYR, TRP1, and TRP2 was decreased in anemonin-treated melanocytes. Additionally, reverse transcription and quantitative real-time polymerase chain reaction analyses revealed that expression of mRNAs for MITF, TYR, TYRP1, and TYRP2 was also suppressed by anemonin.

CONCLUSION

The natural compound, anemonin, an active compound of C. crassifolia, inhibits pigmentation synthesis in human melanocytes. Anemonin inhibits melanin synthesis by inhibiting the transcription of the genes encoding MITF, TYR, TRP1, and TRP2. This natural compound may be a candidate for cosmetic use.

Hypoglycemic effect of syringin from Eleutherococcus senticosus in streptozotocin-induced diabetic rats

Eleutherococcus senticosus (Araliaceae ) is a very powerful adaptogenic agent. In the present study, the effects of syringin, an active principle of this herb, on plasma glucose levels in streptozotocin-induced diabetic rats (STZ-diabetic rats) were investigated. Thirty minutes after syringin was intravenously injected into fasting STZ-diabetic rats, plasma glucose levels dose-dependently decreased. In normal rats, syringin at the effective dose (1.0 mg/kg) significantly attenuated the increase in plasma glucose caused by an intravenous glucose challenge. Syringin dose-dependently (0.01 to 10.0 micromol/L) stimulated glucose uptake in soleus muscle isolated from STZ-diabetic rats. Syringin treatment of hepatocytes isolated from STZ-diabetic rats enhanced glycogen synthesis . The ability of syringin to enhance glucose utilization and lower plasma glucose level in rats suffering from insulin deficiency suggest that this chemical may be useful in the treatment of human diabetes.

Novel ent-Beyeran-19-oic acids from biotransformations of isosteviol metabolites by Mortierella isabellina

Biotransformations of ENT-16beta-hydroxybeyeran-19-oic acid ( 1) by Mortierella isabellina produced hydroxylated metabolites. The isolated metabolites included three new compounds, ent-14beta,16beta-dihydroxybeyeran-19-oic acid ( 3), ent-12beta-hydroxy-16-oxobeyeran-19-oic acid ( 4), and ent-7alpha,12beta-dihydroxy-16-oxobeyeran-19-oic acid ( 5), and one known compound, ent-7alpha,16beta-dihydroxybeyeran-19-oic acid ( 2). The structural elucidation was achieved by detailed analysis of LC-MS chromatograms, and MS and NMR spectroscopic data. In this study, M. isabellina hydroxylated the basic skeleton beyeran-19-oic acid at the 7beta-, 12alpha-, and 14alpha-positions, and oxidized the skeleton at the 16-position. All compounds were evaluated with the cell viability assay. The results of the bioassay indicated that MTT formazan exocytosis occurs upon treatment of the cells with 1.

Immunomodulatory activity of dioscorin, the storage protein of yam (Dioscorea alata cv. Tainong No. 1) tuber

The purified dioscorin from yam (Dioscorea alata L. cv. Tainong 1) tuber was previously reported (Hsu et al., 2002. J. Agric. Food Chem., 50, 6109-6113). In this report, we evaluated its immunomodulatory ability in vitro in the presence of polymyxin B (50 microg/ml) to eliminate lipopolysaccharide (LPS) contamination. Dioscorin (5-100 microg/ml) was able to stimulate nitric oxide production (expressed as nitrite concentrations) in RAW264.7 cells. The stimulation index on the phagocytosis of RAW264.7 cells against E. coli and the oxidative burst (determined by the intensity of rhodamine fluorescence) of RAW264.7 cells were both enhanced by different concentrations of dioscorin (5-100 microg/ml). The cytokine production, including IL-6, TNF-alpha, and IL-1beta in dioscorin-treated RAW264.7 cells or human monocytes, was measured in the cultured medium. Dioscorin (5-100 microg/ml) was found able to induce IL-6, TNF-alpha, and IL-1beta production in RAW264.7 cells and human monocytes. To evaluate the effects of dioscorin on the proliferation of spleen cells from BALB/c mice, phytohemagglutinin (PHA, 2 microg/ml) alone or PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml) was used to treat spleen cells for 24h. The stimulated proliferation index of splenic cells ranged from 1.38- to 1.48-fold of PHA alone for PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml). We suggest that the tuber storage protein of yam dioscorin functions as an immunomodulatory substance.

New constituent from Podocarpus macrophyllus var. macrophyllus shows anti-tyrosinase effect and regulates tyrosinase-related proteins and mRNA in human epidermal melanocytes

A new biflavonoid, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5), and five known compounds, (-)-catechin (1), quercetin (2), 2,3-dihydrosciadopitysin (3), sciadopitysin (4), and isoginkgetin (6), were isolated from Podocarpus macrophyllus var. macrophyllus (Podocarpaceae). These compounds were evaluated their ability to inhibit cellular tyrosinase activity and for their melanin inhibitory activity in human epidermal melanocytes (HEMn). In the melanin synthesis assay, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5) showed a potent anti-tyrosinase effect with IC(50)=0.098 mM in HEMn. It also significantly decreased both protein and mRNA levels of the tyrosinase-related protein-2 (TRP-2) by Western blot and quantitative real-time PCR (qRT-PCR) analysis. These findings suggest that the new compound, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5), is the most active component of P. macrophyllus var. macrophyllus in inhibiting pigmentation and that this inhibition is exerted through inhibition of transcription of the genes encoding TRP2.

Constituents from the Formosan apple reduce tyrosinase activity in human epidermal melanocytes

Tyrosinase is a copper-containing monooxygenase that catalyzes melanin synthesis in skin melanocytes. Herein, 13 compounds from the Formosan apple (Malus doumeri var. formosana), an indigenous Taiwanese plant, were isolated and identified. The active constituents were identified as 3-hydroxyphloretin (7) and catechol (9); they exhibited potent hydroxyl radical-scavenging (IC(50) values, 0.6 and 1.1 microM) and cellular tyrosinase-reducing activities (IC(50) values, 32 and 22 microM) in human epidermal melanocytes. In addition, we evaluated the level of several tyrosinase-related proteins by Western blot analysis. In contrast to 3-hydroxyphloretin (7), which showed no effect on the level of these proteins, catechol (9) reduced their activity and the expression of the respective genes, as determined by quantitative real-time PCR. In a kinetic analysis of mushroom tyrosinase, 3-hydroxyphloretin (7) was a competitive inhibitor. These two constituents exhibited metal-coordinating interactions with copper ions in a virtual model of molecular docking with human tyrosinase. Thus, 3-hydroxyphloretin (7) and catechol (9) were the most active constituents from the Formosan apple; they exhibited anti-oxidant and tyrosinase reducing activities, suggesting their possible use as cosmetic agents.

Hypoxia-inducible factor 1alpha regulates lung adenocarcinoma cell invasion

We studied the role of hypoxia-inducible factor-1alpha (HIF-1alpha) in human lung adenocarcinoma cell invasion using a metastatic cell model composed of low invasive CL1 and highly invasive CL1-5 cells. We showed that HIF-1alpha was expressed in CL1-5 but not in CL1 cells under normoxic condition, and that inhibition of HIF-1alpha expression by a small interfering RNA decreased invasiveness of CL1-5 cells. Complementary, overexpression of HIF-1alpha increased the invasiveness of CL1 and gastric cancer SC-M1 cells. Subsequently, we showed that urokinase-type plasminogen activator receptor (uPAR), and matrix metalloproteinases (MMPs) 1 and 2 were critical in HIF-1alpha-induced invasion. Mechanistic studies revealed that HIF-1alpha overexpression could increase the expression of uPAR and MMP1, but not MMP2. However, ELISA assays on the conditioned media generated from control CL1 and CL1 cells overexpressing HIF-1alpha showed that overexpression of HIF-1alpha increased the levels of endogenous free active MMP2 and total free MMP2, and the former was blocked by inhibition of MMP1 expression. We conclude that (i) HIF-1alpha overexpression enhances lung cancer cell invasion at least through up-regulating the expression and activities of uPAR, MMP1, and MMP2; and (ii) induction of MMP1 participates in cell invasion and also plays an important role in HIF-1alpha-induced activation of MMP2.

Microbial metabolism of steviol and steviol-16alpha,17-epoxide

Steviol (2) possesses a blood glucose-lowering property. In order to produce potentially more- or less-active, toxic, or inactive metabolites compared to steviol (2), its microbial metabolism was investigated. Incubation of 2 with the microorganisms Bacillus megaterium ATCC 14581, Mucor recurvatus MR 36, and Aspergillus niger BCRC 32720 yielded one new metabolite, ent-7alpha,11beta,13-trihydroxykaur-16-en-19-oic acid (7), together with four known related biotransformation products, ent-7alpha,13-dihydroxykaur-16-en-19-oic acid (3), ent-13-hydroxykaur-16-en-19-alpha-d-glucopyranosyl ester (4), ent-13,16beta,17-trihydroxykauran-19-oic acid (5), and ent-13-hydroxy-7-ketokaur-16-en-19-oic acid (6). The preliminary testing of antihyperglycemic effects showed that 5 was more potent than the parent compound (2). Thus, the microbial metabolism of steviol-16alpha,17-epoxide (8) with M. recurvatus MR 36 was continued to produce higher amounts of 5 for future study of its action mechanism. Preparative-scale fermentation of 8 yielded 5, ent-11alpha,13,16alpha,17-tetrahydroxykauran-19-oic acid (10), ent-1beta,17-dihydroxy-16-ketobeyeran-19-oic acid (11), and ent-7alpha,17-dihydroxy-16-ketobeyeran-19-oic acid (13), together with three new metabolites: ent-13,16beta-dihydroxykauran-17-acetoxy-19-oic acid (9), ent-11beta,13-dihydroxy-16beta,17-epoxykauran-19-oic acid (12), and ent-11beta,13,16beta,17-tetrahydroxykauran-19-oic acid (14). The structures of the compounds were fully elucidated using 1D and 2D NMR spectroscopic techniques, as well as HRFABMS. In addition, a GRE (glucocorticoid responsive element)-mediated luciferase reporter assay was used to initially screen the compounds 3-5, and 7 as glucocorticoid agonists. Compounds 4, 5 and 7 showed significant effects.

Biotransformation of gallic acid by Beauveria sulfurescens ATCC 7159

Preparative-scale fermentation of gallic acid (3,4,5-trihydroxybenzoic acid) (1) with Beauveria sulfurescens ATCC 7159 gave two new glucosidated compounds, 4-(3,4-dihydroxy-6-hydroxymethyl-5-methoxy-tetrahydro-pyran-2-yloxy)-3-hydroxy-5-methoxy-benzoic acid (4), 3-hydroxy-4,5-dimethoxy-benzoic acid 3,4-dihydroxy-6-hydroxymethyl-5-methoxy-tetrahydro-pyran-2-yl ester (7), along with four known compounds, 3-O-methylgallic acid (2), 4-O-methylgallic acid (3), 3,4-O-dimethylgallic acid (5), and 3,5-O-dimethylgallic acid (6). The new metabolite genistein 7-O-beta-D-4''-O-methyl-glucopyranoside (8) was also obtained as a byproduct due to the use of soybean meal in the fermentation medium. The structural elucidation of the metabolites was based primarily on 1D-, 2D-NMR, and HRFABMS analyses. Among these compounds, 2, 3, and 5 are metabolites of gallic acid in mammals. This result demonstrated that microbial culture parallels mammalian metabolism; therefore, B. sulfurescens might be a useful tool for generating mammalian metabolites of related analogs of gallic acid (1) for complete structural identification and for further use in investigating pharmacological and toxicological properties in this series of compounds. In addition, a GRE (glucocorticoid response element)-mediated luciferase reporter gene assay was used to initially screen for the biological activity of the 6 compounds, 2-6 and 8, along with 1 and its chemical O-methylated derivatives 9-13. Among the 12 compounds tested, 11-13 were found to be significant, but less active than the reference compounds of methylprednisolone and dexamethasone.

Transformation of steviol-16alpha,17-epoxide by Streptomyces griseus and Cunninghamella bainieri

Eight new ent-beyerane metabolites, 5-8, 12, and 14-16, and four new ent-kaurane metabolites, 3, 10, 11, and 13, together with two known metabolites, 4 and 9, were isolated from the microbial transformations of steviol-16alpha,17-epoxide using Streptomyces griseus ATCC 10137 and Cunninghamella bainieri ATCC 9244. The structures of the metabolites were characterized by IR, HRFABMS, and 1D and 2D NMR data. In addition, a GRE (glucocorticoid response element)-mediated luciferase reporter assay was used to initially screen for the biological activity of the 11 metabolites and stevioside. Steviol (1), steviol-16alpha,17-epoxide (2), ent-11alpha,13,16alpha,17-tetrahydroxykauran-19-oic acid (3), ent-17-hydroxy-16-ketobeyeran-19-oic acid (4), ent-9alpha,13-dihydroxy-16beta,17-epoxykauran-19-oic acid (10), ent-9alpha,17-dihydroxy-16-ketobeyeran-19-oic acid (12), ent-1beta,17-dihydroxy-16-ketobeyeran-19-oic acid (14), and stevioside showed significant effects; in particular, stevioside showed almost equal potency as dexamethasone.

Cosmetic applications of selected traditional Chinese herbal medicines

Because tyrosinase catalyzes melanin synthesis, tyrosinase inhibitors are important in cosmetic skin-whitening. Oxidative stress contributes to skin aging and can adversely affect skin health, which means antioxidants active in skin cells may support skin health. We examined 25 traditional Chinese herbal medicines that might be useful for skin-whitening and skin health. Extracts (100microg/mL) were tested for cytotoxicity on human epidermal melanocytes (HEMn); 12 exhibited low cytotoxicity. Their effects on tyrosinase and melanin inhibitory activities and free radical scavenging activities were further assessed. Phenolic contents were evaluated using Folin-Ciocalteu reagent. Four herbs, Pharbitis nil, Sophora japonica, Spatholobus suberectus, and Morus alba, exhibited potent inhibitory effects on tyrosinase (IC(50) values 24.9, 95.6, 83.9, and 78.3microg/mL, respectively). Melanin inhibition was not dose-dependent. Sophora japonica (IC(50): 14.46microg/mL, 1,1-diphenyl-2-picrylhydrazyl (DPPH); 1.95microg/mL, hydroxyl radical) and Spatholobus suberectus (IC(50): 10.51microg/mL, DPPH; 4.36microg/mL, hydroxyl radical) showed good antioxidative activities and high phenolic contents (255 and 189mg of gallic acid/g extract, respectively). Among active anti-tyrosinase extracts, Sophora japonica and Spatholobus suberectus were especially potent in HEMn cells in terms of free radical scavenging effects and high phenolic contents, making them the strongest candidates for cosmetic application found in the current study.

Bioactive constituents of Spatholobus suberectus in regulating tyrosinase-related proteins and mRNA in HEMn cells

Spatholobus suberectus Dunn (Leguminosae) is a traditional Chinese herbal medicine used to treat rheumatism, anemia, menoxenia, and other disorders. The extent to which this herbal medicine is useful to skin cells, however, has not been evaluated. Constituents of the 95% ethanol extracts of the dried vine stems of S. suberectus were therefore isolated and examined for their skin-whitening capacity. A bio-guided phytochemical investigation, involving use of the mushroom tyrosinase inhibitory system, of active fractions of the extracts resulted in the isolation of 12 constituents. The structures of these constituents, which were characterized by various spectroscopic techniques, consisted of one flavone, three isoflavones, five flavanones, two flavanonols, and one chalcone. Of these constituents 3',4',7-trihydroxyflavone (1), eriodictyol (3), plathymenin (5), dihydroquercetin (6), butin (7), neoisoliquiritigenin (8), dihydrokaempferol (9), liquiritigenin (10), and 6-methoxyeriodictyol (12) represented compounds isolated for the first time from S. suberectus. These constituents were evaluated their ability to inhibit cellular tyrosinase activity and for their melanin inhibitory activity in human epidermal melanocytes (HEMn). Butin (7) was the most efficacious of these constituents and exhibited concentration-dependent effects. Western blot analysis revealed that expression of tyrosinase and tyrosinase-related proteins 1 and 2 (TRP1 and TRP2) was decreased in butin (7)-treated HEMn cells. Additionally, quantitative real-time PCR (qRT-PCR) analysis disclosed that expression of mRNAs for tyrosinase, TRP1 and TRP2 was suppressed by butin (7). It is concluded that butin (7) is the most active of the components of S. suberectus in inhibiting pigmentation and that this inhibition is exerted through inhibition of transcription of the genes encoding tyrosinase, TRP1 and TRP2.

Promotion of hyphal growth and underlying chemical changes in Antrodia camphorata by host factors from Cinnamomum camphora

The aim of this research was to investigate the hyphal growth-promoting factors (HGFs) of Antrodia camphorata from the host-related species, Cinnamomum camphora (CC) and the underlying chemical produced. The HGF was identified in the polysaccharide fraction of CC at levels ranging from 80 to 320 mg L(-1), and it maximally stimulated growth to 5.50 g L(-1) during a 14-day culture period compared to that of the control of 2.88 g L(-1). We also investigated the nature and chemical composition of the CC polysaccharide. Herein, size-exclusion column chromatography followed by high-performance anion-exchange chromatography after complete hydrolysis of the CC polysaccharide was performed to derive its molecular weight and sugar composition. The Mw values of the CC polysaccharide were determined to be 728.2, 187.5, 28.7, 7.5, and 1.9 kDa. Compositional analysis of the CC polysaccharide showed that galactosamine, mannose, and glucose were the major monosaccharides. Time-course studies of mycelial extracts of cultures revealed that prolonged incubation with the water-soluble extracts of CC resulted in an increase in the relative amounts of two lanostane-type compounds, i.e., dehydrosulphurenic acid and 15alpha-acetyl-dehydrosulphurenic acid, which are found in the fruiting bodies of A. camphorata. This finding offers the possibility of the reliable production of this medicinal fungus under laboratory conditions compared to its limited slow growth in nature.