Showing papers in "Chemical & Pharmaceutical Bulletin in 2001"

In vitro and in vivo study of two types of long-circulating solid lipid nanoparticles containing paclitaxel.

Abstract: Paclitaxel, a diterpenoid derived from the needles and bark of the Pacific yew tree, is a potent inhibitor of cell replication, blocking cells in the late G 2 -mitotic phase of the cell cycle by stabilizing the microtuble cytoskeleton. Clinical trials have shown that paclitaxel has antineoplastic activity, particularly against primary epithelial ovarian carcinoma, breast cancer, colon, head and neck cancers and non-small cell lung cancer. 1) Paclitaxel is a hydrophobic molecule and poorly soluble in water, for which reason it is solubilized in a 50 : 50 mixture of Cremophor EL (a polyethoxylated castor oil) and ethanol. Cremophor EL is associated with a number of side effect, including hypersensitivity, nephrotoxicity and neurotoxicity. Furthermore, Cremophor EL dissolves phthalate plastics from commonly used polyvinyl chloride bags and intravenous infusion lines. 2) The use of Cremophor EL as a vehicle also appears to alter the biochemical properties of lipoproteins, such as high-density lipoprotein; it has also been shown to mediate partially the cytotoxic activities of paclitaxel in primary cultures of tumor cells from patients. 3) Although a premeditation regimen with corticosteroids and antihistamine reduces the incidence of serious hypersensitivity reactions, milder reactions have still been found to occur in 5—30% of treated patients. 3) Colloidal drug carriers such as liposomes and nanoparticles can be used to improve the therapeutics index of both established and new drugs by modifying their distribution, thus increasing their efficiency and/or reducing their toxicity. This is because the drug distribution then follows the carrier, rather than depending on the physicochemical properties of the drug. 4)

Studies on the constituents of the leaves of Morus alba L.

Abstract: Two novel prenylflavanes (1, 2) and a glycoside (3) of 1 were isolated along with six known compounds, isoquercitrin (4), astragalin (5), scopolin (6), skimmin (7), roseoside II (8) and benzyl D-glucopyranoside (9), from the leaves of Morus alba. The inhibitory activities of compounds 1, 2 and 3 on the oxidation of human low density lipoprotein (LDL) were investigated.

Medicinal Foodstuffs. XXI. Structures of New Cucurbitane-Type Triterpene Glycosides, Goyaglycosides-a, -b, -c, -d, -e, -f, -g, and -h, and New Oleanane-Type Triterpene Saponins, Goyasaponins I, II, and III, from the Fresh Fruit of Japanese Momordica charantia L.

Abstract: Eight cucurbitane-type triterpene glycosides called goyaglycosides-a, -b, -c, -d, -e, -f, -g, and -h and three oleanane-type triterpene saponins termed goyasaponins I, II, and III were isolated from the fresh fruit of Japanese Momordica charantia L. (Cucurbitaceae) together with five known cucurbitane-type triterpene glycosides momordicosides A, C, F1, I, and K. The structures of goyaglycosides and goyasaponins were elucidated on the basis of chemical and physicochemical evidence.

Chemical Constituents of Prangos tschimganica; Structure Elucidation and Absolute Configuration of Coumarin and Furanocoumarin Derivatives with Anti-HIV Activity

Abstract: The methanol extract of the dried aerial parts of Prangos tschimganica gave three new coumarin derivatives and 30 known coumarin derivatives. Their structures were established on the basis of chemical and spectroscopic evidence. Absolute configuration of the isolated compounds were determined by using a modified Mosher's method. Some of the isolated compounds showed anti-HIV activity.

Medicinal flowers. III. Marigold. (1): hypoglycemic, gastric emptying inhibitory, and gastroprotective principles and new oleanane-type triterpene oligoglycosides, calendasaponins A, B, C, and D, from Egyptian Calendula officinalis.

Abstract: The methanolic extract and its 1-butanol-soluble fraction from the flowers of Calendula officinalis were found to show a hypoglycemic effect, inhibitory activity of gastric emptying, and gastroprotective effect. From the 1-butanol-soluble fraction, four new triterpene oligoglycosides, calendasaponins A, B, C, and D, were isolated, together with eight known saponins, seven known flavonol glycosides, and a known sesquiterpene glucoside. Their structures were elucidated on the basis of chemical and physicochemical evidence. The principal saponin constituents, glycosides A, B, C, D, and F, exhibited potent inhibitory effects on an increase in serum glucose levels in glucose-loaded rats, gastric emptying in mice, and ethanol- and indomethacin-induced gastric lesions in rats. Some structure-activity relationships are discussed.

A novel antivirally active fucan sulfate derived from an edible brown alga, Sargassum horneri.

Abstract: A novel fucan sulfate (Hor-1) was isolated from the hot water extract of an edible brown alga, Sargassum horneri (Turner) C AGARDH The fucan sulfate was revealed to have sugar linkage types, sulfate content and uronic acid content different from those of sodium hornan (Na-HOR), another fucan sulfate isolated from this alga However, it exhibited inhibitory activity against replication of herpes simplex virus type 1 with similar potency to Na-HOR

Medicinal foodstuffs. XXVII. Saponin constituents of gotu kola (2): structures of new ursane- and oleanane-type triterpene oligoglycosides, centellasaponins B, C, and D, from Centella asiatica cultivated in Sri Lanka.

Abstract: Ursane- and oleanane-type triterpene oligoglycosides, centellasaponins B, C, and D, were isolated from the aerial parts of Centella asiatica (L.) Urban cultivated in Sri Lanka together with madecassoside, asiaticoside, asiaticoside B, and sceffoleoside A. The chemical structures of centellasaponins B, C, and D were determined on the basis of chemical and physicochemical evidence to be madecassic acid 28-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside, madasiatic acid 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside, and 3beta,6beta,23-trihydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside, respectively.

Analgesic components of saposhnikovia root (Saposhnikovia divaricata).

Abstract: By activity-oriented separation using the writhing method in mice, the analgesic components of Saposhnikovia root (Saposhnikovia divaricata Schischkin; Umbelliferae) were identified to be chromones, coumarins, polyacetylenes and 1-acylglycerols. Two new components, divaricatol and (3'S)-hydroxydeltoin, were also isolated. The most potent analgesia was observed in chromones such as divaricatol, ledebouriellol and hamaudol, which inhibited writhing inhibition at an oral dose of 1 mg/kg in mice. Acylglycerols also showed inhibition significantly at a dose of 5 mg/kg. In some pharmacological tests using sec-O-glucosylhamaudol, the compound showed analgesia by the tail pressure and the Randall & Selitto methods, and its writhing inhibition was not reversed by naloxone.

The Heterocyclic Ring Fission and Dehydroxylation of Catechins and Related Compounds by Eubacterium Sp. Strain SDG-2, a Human Intestinal Bacterium

Abstract: A human intestinal bacterium, Eubacterium (E.) sp. strain SDG-2, was tested for its ability to metabolize various (3R)- and (3S)-flavan-3-ols and their 3-O-gallates. This bacterium cleaved the C-ring of (3R)- and (3S)-flavan-3-ols to give 1,3-diphenylpropan-2-ol derivatives, but not their 3-O-gallates. Furthermore, E. sp. strain SDG-2 had the ability of p-dehydroxylation in the B-ring of (3R)-flavan-3-ols, such as (-)-catechin, (-)-epicatechin, (-)-gallocatechin and (-)-epigallocatechin, but not of (3S)-flavan-3-ols, such as (+)-catechin and (+)-epicatechin.

Effects of constituents from the bark of Magnolia obovata on nitric oxide production in lipopolysaccharide-activated macrophages.

Abstract: The methanolic extract from a Japanese herbal medicine, the bark of Magnolia obovata, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophages By bioassay-guided separation, three neolignans (magnolol, honokiol, obovatol) and three sesquiterpenes (alpha-eudesmol, beta-eudesmol, gamma-eudesmol) were obtained as active constituents A trineolignan (magnolianin), a phenylpropanoid glycoside (syringin), lignan glycosides (liriodendrin, (+)-syringaresinol 4'-O-beta-D-glucopyranoside) and a sesquiterpene (caryophyllene oxide) did not show any activity On the other hand, sesquiterpene-neolignans (eudesmagnolol, clovanemagnolol, caryolanemagnolol, eudeshonokiol A, eudesobovatol A) showed the strong cytotoxic effects Active constituents (magnolol, honokiol, obovatol) showed weak inhibition for inducible NO synthase (iNOS) enzyme activity, but potent inhibition of iNOS induction and activation of nuclear factor-kappaB

Preparation of rapidly disintegrating tablet using new types of microcrystalline cellulose (PH-M series) and low substituted-hydroxypropylcellulose or spherical sugar granules by direct compression method.

Abstract: To decrease the sensation of roughness when a tablet, which is rapidly disintegrated by saliva (rapidly disintegrating tablet), is orally taken, we prepared rapidly disintegrating tablets using microcrystalline cellulose (Avicel PH-M series), a new type of pharmaceutical excipient that is spherical and has a very small particle size (particle size, 7-32 microm), instead of conventional microcrystalline cellulose (PH-102) used in the formulation of tablets containing acetaminophen or ascorbic acid as model drugs for tableting study. Tablets (200 mg) prepared using spherical microcrystalline cellulose, PH-M-06, with the smallest particle size (mean value, 7 microm) had sufficient crushing tolerance (approximately, 8 kg) and were very rapidly, disintegrated (within 15 s) when the mixing ratio of PH-M-06 to low-substituted hydroxypropylcellulose (L-HPC) was 9:1. Sensory evaluation by volunteers showed that PH-M-06 was superior to PH-102 in terms of the feeling of roughness in the mouth. Consequently, it was found that particle size is an important factor for tablet preparation using microcrystalline cellulose. It is possible to prepare drugs such as acetaminophen and ascorbic acid (concentration of approximately 50%) in the tablet form using PH-NM-06 in combination with L-HPC as a good disintegrant at a low compression force (1-6 kN). To solve the problem of poor fluidity in the preparation of these tablets, we investigated the use of spherical sugar granules (Nonpareil, NP-101 (sucrose and starch, composition ratio of 7:3), NP-103 (purified sucrose), NP-107 (purified lactose) and NP-108 (purified D-mannitol)). Rapidly disintegrating tablets can be prepared by the direct compression method when suitable excipients such as fine microcrystalline cellulose (PH-M-06) and spherical sugar granules (NP) are used.

Analysis of the marker compounds of Rhodiola rosea L. (golden root) by reversed phase high performance liquid chromatography.

Abstract: An HPLC method permitting the first simultaneous detection of 5 marker compounds (salidroside, rosarin, rosavin, rosin, rosiridin) of R. rosea was developed. A separation was achieved within 27 min by using C-18 column material, a phosphate buffer/acetonitrile gradient system and at a separation temperature of 60 degrees C. All five compounds could be detected at concentrations as low as 0.62 microg/ml and were clearly assignable in R. rosea plant material and commercial products. Therefore, this quantitative and qualitative applicability of the method offers efficient and reliable means for the evaluation of R. rosea and products thereof.

In vitro evaluation of secoiridoid glucosides from the fruits of Ligustrum lucidum as antiviral agents

Abstract: Six secoiridoid glucosides, lucidumoside C (1), oleoside dimethylester (2), neonuezhenide (3), oleuropein (4), ligustroside (5) and lucidumoside A (6), isolated from the fruits of Ligustrum lucidum (Oleaceae), were examined in vitro for their activities against four strains of pathogenic viruses, namely herpes simplex type I virus (HSV-1), influenza type A virus (Flu A), respiratory syncytial virus (RSV) and parainfluenza type 3 virus (Para 3). Antiviral activities were evaluated by the cytopathic effect (CPE) inhibitory assay. The purpose was to check if the antioxidative potency of these glucosides correlated with their antiviral potency. Results showed that none of the glucosides had any significant activity against HSV-1 and Flu A. Oleuropein, however, showed significant antiviral activities against RSV and Para 3 with IC50 value of 23.4 and 11.7 microg/ml, respectively. Lucidumoside C, oleoside dimethylester and ligustroside showed potent or moderate antiviral activities against Para 3 with IC50 values of 15.6-20.8 microg/ml. These results also documented that the anti-oxidative potency of these secoiriodoid glucosides was not directly related to their antiviral effects.

Two New Pyrrolidine Alkaloids, Radicamines A and B, as Inhibitors of α-Glucosidase from Lobelia chinensis LOUR.

Abstract: Two new pyrrolidine alkaloids, radicamines A and B were isolated as inhibitors of alpha-glucosidase from Lobelia chinensis Lour. (Campanulaceae). Radicamines A and B were formulated as (2S,3S,4S,5S)-2-hydroxymethyl-3,4-dihydroxy-5-(3-hydroxy-4-methoxyphenyl)-pyrrolidine (1) and (2S,3S,4S,5S)-2-hydroxymethyl-3,4-dihydroxy-5-(4-hydroxyphenyl)-pyrrolidine (2) on the basis of spectroscopic analyses and chemical methods.

Medicinal foodstuffs. XXVIII. Inhibitors of nitric oxide production and new sesquiterpenes, zedoarofuran, 4-epicurcumenol, neocurcumenol, gajutsulactones A and B, and zedoarolides A and B, from Zedoariae Rhizoma.

Abstract: A new eudesmane-type sesquiterpene, zedoarofuran, and six new guaiane- or seco-guaiane-type sesquiterpenes, 4-epicurcumenol, neocurcumenol, gajutsulactones A and B, and zedoarolides A and B, were isolated from aqueous acetone extract of Zedoariae Rhizoma together with 36 known sesquiterpenes and two diarylheptanoids. Their stereostructures were elucidated on the basis of chemical and physicochemical evidence. The effects of isolated components on nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages were examined and 16 sesquiterpenes including gajutsulactones A and B, and bis(4-hydroxycinnamoyl)methane were found to show inhibitory activity.

Radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl of ascorbic acid 2-glucoside (AA-2G) and 6-acyl-AA-2G.

Abstract: The radical scavenging activity of the stable derivatives, which are O-substituted at the C-2 position of ascorbic acid (AA), against 1,1-diphenyl-2-picrylhydrazyl (DPPH) was evaluated in buffer under different pH conditions, and compared with those of AA and alpha-tocopherol. AA was shown to have 50% radical scavenging ability (EC50) at a concentration of 2.2 x 10(-5) M against 0.1 mM DPPH in 60% ethanol. Ascorbyl 6-palmitate, a lipophilic AA derivative which has a free endiol group and is therefore unstable, also showed potent radical scavenging activity with EC50 of 2.9 x 10(-5) M. A typical lipophilic antioxidant, alpha-tocopherol gave a similar EC50 value as that of AA. In contrast, ascorbyl 2,6-dipalmitate, AA 2-phosphate and AA 2-sulfate exhibited negligible scavenging activity. On the other hand, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and a series of 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G) themselves exhibited the radical scavenging activity of EC50: 6.1 x 10(-5) M and 4.4 x 10(-5)-5.9 x 10(-5) M, respectively, although their activities were lower than that of AA. Among 6-Acyl-AA-2G derivatives, the EC50 values tended to decrease with increasing length of their acyl carbon group. Increasing pH of the buffer resulted in decrease in the scavenging activity of all compounds tested as expected. We speculate that the difference in the radical scavenging activity of derivatives O-substituted at the C-2 position of AA may be ascribed to the linkage type of the substituent group to the endiol-lactone resonance system and the degree of dissociation of the C-3 proton.

Six new dammarane-type triterpene saponins from the leaves of Panax ginseng.

Abstract: Six new minor saponins, together with known ginsenosides, were isolated from the leaves of Panax ginseng. The new saponins were named as ginsenoside-Rh5, -Rh6, -Rh7 -Rh8, -Rh9 and -Rg7, and their structures were elucidated on the basis of chemical and physicochemical evidence to be as follows: ginsenoside-Rh5: 3beta,6alpha,12beta,24zeta-tetrahydroxy-dammar-20(22),25-diene 6-O-beta-D-glucopyranoside (1), -Rh6: 3beta,6alpha12beta,20(S)-tetrahydroxy-25-hydroperoxy-dammar-23-ene 20-O-beta-D-glucopyranoside (2), -Rh7: 3beta,7beta,12beta,20(S)-tetrahydroxy-dammar-5,24-diene 20-O-beta-D-glucopyranoside (3), -Rh8: 3beta,6alpha,20(S)-trihydroxy-dammar-24-ene-12-one 20-O-beta-D-glucopyranoside (4), -Rh9: 3beta,6alpha,20(S)-trihydroxy-12beta,23-epoxy-dammar-24-ene 20-O-beta-D-glucopyranoside (5) and -Rg7: 3-O-beta-D-glucopyranosyl 3beta,12beta,20(S),24(R)-tetrahydroxy-dammar-25-ene 20-O-beta-D-glucopyranoside (6).

Ten New Labdane-Type Diterpenes from the Fruit of Vitex rotundifolia

Abstract: Ten new labdane-type diterpenes were isolated from the fruit of Vitex rotundifolia L. (Verbenaceae), along with a known diterpene, vitexilactone. Their chemical structures were determined on the bases of spectroscopic data.

Antioxidative glucosides from the fruits of Ligustrum lucidum

Abstract: The ethanol extract of the fruits of Ligustrum lucidum was shown to have inhibitory effects on the hemolysis of red blood cells induced by 2,2'-azo-bis-(2-amidinopropane) dihydrochloride. Bioassay-guided analysis led to the isolation of ten secoiridoid glucosides. Two of them were new, lucidumosides C and D. Their structures were elucidated by spectroscopic methods. The other eight compounds were identified as oleoside dimethyl ester, ligustroside, oleuropein, nuezhenide, isonuezhenide, neonuezhenide, lucidumoside A and lucidumoside B. Five compounds, oleoside dimethyl ester, oleuropein, neonuezhenide, lucidumoside B and lucidumoside C, exhibited strong antioxidant effect against hemolysis of red blood cells induced by free radicals.

New phenolic constituents from the fruit juice of Phyllanthus emblica.

Abstract: Six new phenolic constituents, L-malic acid 2-O- (1), mucic acid 2-O- (5), mucic acid 1,4-lactone 2-O- (6), 5-O- (8), 3-O- (10), and 3,5-di-O- (11) gallates, were isolated from the fruit juice of Phyllanthus emblica together with their methyl esters (2-4, 7, 9), and their structures were determined by spectral and chemical methods. Compounds 5, 6, and 8, the major phenolic constituents of the juice, were present as an equilibrium mixture in aqueous solution.

Prolyl endopeptidase inhibitors from the underground part of Rhodiola sachalinensis

Abstract: The methanolic extract of the underground part of Rhodiola sachalinensis was found to show inhibitory activity on prolyl endopeptidase (PEP, EC. 3.4.21.26), an enzyme that plays a role in the metabolism of proline-containing neuropeptidase which is recognized to be involved in learning and memory. From the MeOH extract, five new monoterpenoids named sachalinols A (24), B (25) and C (26) and sachalinosides A (23) and B (27) were isolated, together with twenty-two known compounds, gallic acid (1), trans-p-hydroxycinnamic acid (2), p-tyrosol (3), salidroside (4), 6n-O-galloylsalidroside (5), benzyl beta-D-glucopyranoside (6), 2-phenylethyl beta-D-glucopyranoside (7), trans-cinnamyl beta-D-glucopyranoside (8), rosarin (9), rhodiocyanoside A (10), lotaustralin (11), octyl beta-D-glucopyranoside (12), 1,2,3,6-tetra-O-galloyl-beta-D-glucose (13), 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (14), kaempferol (15), kaempferol 3-O-beta-D-xylofuranosyl(1-->2)-beta-D-glucopyranoside (16), kaempferol 3-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside (17), rhodionin (18), rhodiosin (19), (-)-epigallocatechin (20), 3-O-galloylepigallocatechin-(4-->8)-epigallocatechin 3-O-gallate (21) and rosiridin (22). Among these, nineteen compounds other than 3, 4 and 9 have been isolated for the first time from R. sachalinensis, and six (6, 8, 13, 16, 17, 20) are isolated from Rhodiola plants for the first time. Among them, six compounds (13, 14, 18, 19, 21, 22) showed noncompetitive inhibition against Flavobacterium PEP, with an IC50 of 0.025, 0.17, 22, 41, 0.44 and 84 microM, respectively.

Multifunctional asymmetric catalysis.

Abstract: Two types of general and practical enantioselective catalysts, namely, bimetallic complexes and Lewis acid-Lewis base bifunctional catalysts were developed based on the concept of multifunctional catalysis. In the first part of this review, the first example of a catalytic enatioselective nitro-Mannich reaction as well as a direct catalytic enantioselective aldol reaction of 2-hydroxyacetophenone using bimetallic complexes is discussed. The new complex, composed of ytterbium, potassium, and BINOL in a ratio of 1:1:3, promoted the nitro-Mannich reaction of nitromethane with up to 91% ee. On the other hand, second generation ALB catalyzed an enantioselective and diastereoselective nitro-Mannich reaction of nitroalkanes in up to 83% ee with a diastereomeric ratio up to 7:1. Moreover, the reaction of aldehydes with 2-hydroxyacetophenone in the presence of LLB, KHMDS, and H2O selectively gave the corresponding anti-alpha,beta-dihydroxy ketones in up to 95% ee and, in the presence of the catalyst prepared from linked-BINOL and 2 eq of Et2Zn, selectively afforded the syn-alpha,beta-dihydroxy ketones in up to 86% ee. In the second part, the development of new catalysts displaying a Lewis acidity and a Lewis basicity is described. The Lewis acid of the catalyst activates aldehydes, imines, acyl quinoliniums, and ketones. At the same time, the Lewis base activates the nucleophile (TMSCN). Catalysts of this type produced a highly enantioselective cyanation of these electrophiles. Application of the catalytic enantioselective cyanosilylation of aldehydes to a total synthesis of epothilones is also described.

Studies on the Constituents of Bark of Parameria laevigata MOLDENKE

Abstract: One new trimeric proanthocyanidin, epicatechin-(2beta-->O-->7, 4beta-->6)-epicatechin-(2beta-->O--->7, 4beta-->8)-epicatechin (5) and two new tetrameric proanthocyanidins, epicatechin-(2beta-->O-->7, 4beta-->8)-[epicatechin-(4beta-->6)]-epicatechin-(4beta-->8)-epicatechin, named as parameritannin A-1 (6), and epicatechin-(2beta-->O-->5, 4beta-->6)-[epicatechin-(2beta-->O-->7, 4beta-->8)]-epicatechin-(4beta-->8)-epicatechin, named as parameritannin A-2 (7), have been isolated from the bark of Parameria laevigata Moldenke (Apocynaceae) along with the two known dimers, proanthocyanidin A-2 (1) and proanthocyanidin A-6 (2), and two trimers, cinnamtannin B-1 (3) and aesculitannin B (4). These structures were elucidated by spectral and chemical evidence.

Studies on a Medicinal Parasitic Plant: Lignans from the Stems of Cynomorium songaricum

Abstract: Eight phenolic compounds including two new lignan glucopyranosides together with a known alkaloid were isolated from the stems of Cynomorium songaricum RUPR. (Cynomoriaceae). Their chemical structures were elucidated on the basis of spectral and chemical evidence. The chemotaxonomic significance of these metabolites is discussed.

Relationship of electrochemical oxidation of catechins on their antioxidant activity in microsomal lipid peroxidation.

Abstract: The oxidation potentials of catechins were measured by employing flow-through column electrolysis. The oxidation potentials of catechins were shown to depend on their structures. At the same time, the antioxidant activity of catechins on NADPH-dependent lipid peroxidation in rat liver microsomes was evaluated. Catechins showed a 50% inhibition of lipid peroxidation in the concentration range of 10-51 microM. Among those studied, galloylated catechins exhibited stronger antioxidant activities than those of nongalloylated catechins. A quantitative relationship has been obtained to describe the antioxidant activity of catechins: log IC50 (microM)= 1.56+2.49E1/2 (V)-0.29 logP (r=0.907), where IC50 represents the concentration for 50% inhibition of lipid peroxidation, E1/2 represents the half-wave potential of the first oxidation wave, and P represents the octanol/water partition coefficient. This relationship suggested two important characteristics determining catechin antioxidant activity, namely the ease of oxidation and the lipophilicity.

Bioactive saponins and glycosides. XIX. Notoginseng (3): immunological adjuvant activity of notoginsenosides and related saponins: structures of notoginsenosides-L, -M, and -N from the roots of Panax notoginseng (Burk.) F. H. Chen.

Abstract: New dammarane-type triterpene saponins, notoginsenosides-L, -M, and -N, were isolated from the glycosidic fraction of the dried roots of Panax notoginseng (Burk.) F. H. Chen. Their structures were elucidated on the basis of chemical and physicochemical evidence. Immunological adjuvant activities of the principal notoginsenosides and related dammarane-type triterpene saponins were examined and notoginsenosides-D, -G, -H, and -K were found to increase the serum IgG level in mice sensitized with ovalbumin.

Inhibitory effects on HIV-1 protease of tri-p-coumaroylspermidine from Artemisia caruifolia and related amides.

Abstract: From a methanol extract of Artemisia caruifolia, which showed a moderate inhibitory activity on HIV-1 protease in a preliminary screening, N1, N5, N10-tri-p-coumaroylspermidine and three dicaffeoylquinic acids were isolated. The former compound was found to appreciably inhibit HIV-1 protease. Of related amides which were chemically synthesized, N1, N5, N10, N14-tetra-p-coumaroylspermine and N1, N4, N7, N10, N13-penta-p-coumaroyltetraethylenepentamine inhibited HIV-1 protease more potently than N1, N5, N10-tri-p-coumaroylspermidine.

Thermal behaviour of diclofenac sodium: decomposition and melting characteristics

Abstract: The thermal behaviour and melting characteristics of diclofenac sodium were investigated using various instrumental techniques--differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy and thin layer chromatography (TLC). DSC analysis of diclofenac sodium performed under dynamic flow of either synthetic air or helium or nitrogen did not produce any sharp endothermic peak characteristic of melting peak of a pure substance. Both the rate of scanning of the sample and the environmental atmospheric condition significantly affected the thermographic profile of diclofenac sodium. An exothermic peak prior to an endothermic peak corresponding to melting of the substance appeared when heated under dynamic flow of synthetic air suggesting oxidation (decomposition) of diclofenac sodium before reaching its melting point. In fact, at a scanning rate of 1 degree C/min only the exothermic peak appeared in the thermogram, suggesting complete decomposition prior to melting under the dynamic flow of synthetic air. DSC, FT-IR and TLC data obtained from samples heated under the dynamic flow of either helium or nitrogen revealed formation of a related compound, 1-(2,6-dichlorophenyl)-indolin-2-one, an indol-cyclic amide, as a result of an intramolecular cyclization reaction during the heating process. TGA data demonstrated a loss of 11.4-20.2% of the mass of diclofenac sodium when heated under various environmental conditions, and also supported the oxidative nature of degraded product(s) when the thermal process occurred slowly under a dynamic flow of synthetic air.

Evaluation of flow properties of dry powder inhalation of salbutamol sulfate with lactose carrier

Abstract: The effects of the flow and packing properties of a drug/carrier powder mixture on emission of drug adhering to the carrier from capsules and inhalation devices were investigated. Model powder mixtures were designed consisting of lactose carriers with different particle shapes were prepared by surface treatment and micronized salbutamol sulfate. These powder mixtures were aerosolized by a Spinhaler, and in vitro deposition properties of salbutamol sulfate were evaluated by a twin impinger. The flow properties of the mixed powders were evaluated by the Carr's flowability index (FI) and Hausner's ratio (HR). The packing properties of the mixed powders were determined employing the tapping method. Compared with the powder mixed with the untreated lactose carrier, the FI, HR, and the constant K in Kawakita's equation of the powder mixture prepared using the surface-treated lactose carrier were significantly different, showing that the flow and packing properties of the drug/carrier powder mixture were improved. Using this surface-treated system, the handling of the powder mixture when packing into capsules is improved, which is desirable for handling dry powder inhalants. The fraction (%) of drug emitted from capsules and devices (EM) and the FI of the powder mixture were correlated. As the flow properties improved, the outflow of the powder mixture from capsules and devices became easier, and emission of drug adhering on the carrier from capsules and devices improved. Improvement of the inhalation process, such as the drug particles emitted from the inhalation system, is valuable for increasing inhalation properties of dry powder inhalation.

Kaempferol acetylrhamnosides from the rhizome of Dryopteris crassirhizoma and their inhibitory effects on three different activities of human immunodeficiency virus-1 reverse transcriptase.

Abstract: Three new kaempferol glycosides, called crassirhizomosides A (1), B (2) and C (3), were isolated from the rhizome of Dryopteris crassirhizoma (Aspidiaceae), together with the known kaempferol glycoside, sutchuenoside A (4). The structures of 1-3 were determined as kaempferol 3-alpha-L-(2,4-di-O-acetyl)rhamnopyranoside-7-alpha-L-rhamnopyranoside, kaempferol 3-alpha-L-(3,4-di-O-acetyl)rhamnopyranoside, and kaempferol 3-alpha-L-(2,3-di-O-acetyl)rhamnopyranosside-7-alpha-L-rhamnopyranoside, respectively, by chemical and spectroscopic means. Inhibitory effects of 1-4 and kaempferol on human immunodeficiency virus reverse transcriptase-associated DNA polymerase (RNA-dependent DNA polymerase and DNA-dependent DNA polymerase) and RNase H activities were investigated.