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A quantitative analytical method for five aporphine alkaloids, nuciferine (1), nornuciferine (2), N-methylasimilobine (3), asimilobine (4), and pronuciferine (5), and five benzylisoquinoline alkaloids, armepavine (6), norarmepavine (7), N-methylcoclaurine (8), coclaurine (9), and norjuziphine (10), identified as the constituents responsible for the melanogenesis inhibitory activity of the extracts of lotus flowers (the flower buds of Nelumbo nucifera), has been developed using liquid chromatography-mass spectrometry. The optimum conditions for separation and detection of these 10 alkaloids were achieved on a πNAP column, a reversed-phase column with naphthylethyl group-bonded silica packing material, with CH3CN–0.2% aqueous acetic acid as the mobile phase and using mass spectrometry equipped with a positive-mode electrospray ionization source. According to the protocol established, distributions of these 10 alkaloids in the petal, receptacle, and stamen parts, which were separated from the whole flower, were examined. As expected, excellent correlations were observed between the total alkaloid content and melanogenesis inhibitory activity. Among the active alkaloids, nornuciferine (2) was found to give a carbamate salt (2′′) via formation of an unstable carbamic acid (2′) by absorption of carbon dioxide from the air.

Using an in silico method, seven analogs bearing hydrophobic substituents (8a: Me, 8b: Et, 8c: n-Pent, 8d: n-Hept, 8e: n-Tridec, 8f: isoBu and 8g: neoPent) at the 3'-O-position in salacinol (1), a highly potent natural α-glucosidase inhibitor from Ayurvedic traditional medicine 'Salacia', were designed and synthesized. In order to verify the computational SAR assessments, their α-glucosidase inhibitory activities were evaluated in vitro. All analogs (8a-8g) exhibited an equal or considerably higher level of inhibitory activity against rat small intestinal α-glucosidases compared with the original sulfonate (1), and were as potent as or higher in potency than the clinically used anti-diabetics, voglibose, acarbose or miglitol. Their activities against human maltase exhibited good relationships to the results obtained with enzymes of rat origin. Among the designed compounds, the one with a 3'-O-neopentyl moiety (8g) was most potent, with an approximately ten fold increase in activity against human maltase compared to 1.

Three gedunin-type limonoids, gedunin (1), 6α-acetoxygedunin (2), and 7-deacetoxy-7-oxogedunin (3), which were isolated from the seed and flower oils of andiroba (Carapa guianensis Aublet, Meliaceae), exhibited hepatoprotective effects at doses of 25 mg/kg, p.o. against d-galactosamine (d-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. To characterize the mechanisms of action of 1–3 and clarify the structural requirements for their hepatoprotective effects, 17 related limonoids (1–17) isolated from the seed and/or flower oils of C. guianensis were examined in in vitro studies assessing their effects on (i) d-GalN-induced cytotoxicity in primary cultured mouse hepatocytes, (ii) LPS-induced nitric oxide (NO) production in mouse peritoneal macrophages, and (iii) tumor necrosis factor-α (TNF-α)-induced cytotoxicity in L929 cells. The mechanisms of action of 1–3 are likely to involve the inhibition of LPS-induced macrophage activation and reduced sensitivity of hepatocytes to TNF-α; however, these compounds did not decrease the cytotoxicity caused by d-GalN. In addition, the structural requirements of limonoids (1–17) for inhibition of LPS-induced NO production in mouse peritoneal macrophages and TNF-α-induced cytotoxicity in L929 cells were evaluated.

Seven oleanane-type triterpene saponin bisdesmosides, perennisaponins N-T (1-7), were newly isolated from a methanol extract of daisy, the flowers of Bellis perennis L. (Asteraceae). The structures were determined based on chemical and physicochemical data and confirmed using previously isolated related compounds as references. The isolates, including 13 previously reported perennisaponins A-M (8-20), exhibited anti-proliferative activities against human digestive tract carcinoma HSC-2, HSC-4, and MKN-45 cells. Among them, perennisaponin O (2, IC50 = 11.2, 14.3, and 6.9 μM, respectively) showed relatively strong activities. The mechanism of action of 2 against HSC-2 was found to involve apoptotic cell death.

Three new flavonol glycosides, sarmenosides V–VII ( 1 – 3 ), were isolated from the whole plant of Sedum sarmentosum (Crassulaseae). The structures of 1 – 3 were determined on the basis of spectroscopic analysis. Among the flavonoid constituents from S. sarmentosum , 1 and 3 were found to show oleic acid–albumin-induced lipid accumulation inhibitory activity.

A quantitative analytical method was developed for the determination of acylated oleanane-type triterpene saponins, chakasaponins I-III (1-3) and floratheasaponins A-F (4-9), found in Camellia sinensis (Theaceae). The practical conditions for separation and detection of these saponins were established on an ODS column with methanol containing 5 mM trifluoroacetic acid as a mobile phase, and the detection and quantitation limits of the method were estimated to be 1.1-3.8 and 3.5-12.5 ng, respectively. The relative standard deviation values of intra- and interday precision were lower than 2.35 and 6.12%, respectively, overall mean recoveries of all saponins being 94.7-108.8%, and the correlation coefficients of all the calibration curves showed good linearity within the test ranges. To approve the validity of the protocol, extracts of 13 kinds of C. sinensis collected in China, Taiwan, Japan, and India were evaluated. The results indicated that the assay was reproducible and precise, and could be readily utilized for the quality evaluation of tea flowers. It was noteworthy that the distinct regional difference was observed with respect to the content of chakasaponins and floratheasaponins, more chakasaponins being contained in the extracts of tea flowers from Fujian and Sichuan provinces, China than those from Japan, Taiwan, and India. Optimum conditions for the extraction process were also established.

A methanol extract of the bark of Shorea roxburghii (Dipterocarpaceae) was found to inhibit plasma glucose elevation in sucrose-loaded mice. From the extract, three new 3-ethyl-4-phenyl-3,4-dihydroisocoumarins, 1′ S -dihydrophayomphenol A 2 ( 1 ) and phayomphenols B 1 ( 2 ) and B 2 ( 3 ), were isolated together with 24 known compounds including 20 stilbenoids and oligostilbenoids. The structures of 1 – 3 were determined on the basis of their spectroscopic properties as well as of chemical evidences. Among the isolates, (−)-hopeaphenol ( 6 ), hemsleyanol D ( 8 ), (+)-α-viniferin ( 15 ), and (−)-balanocarpol ( 18 ) showed inhibitory activity against plasma glucose elevation in sucrose-loaded rats at doses of 100–200 mg/kg, p.o. To clarify the mode of action of the antihyperglycemic property, effects of these oligostilbenoids on gastric emptying in mice, those on glucose uptake in isolated intestinal tissues as well as inhibitory activities against rat intestinal α-glucosidase and rat lens aldose reductase were examined.

Two new phenolic glycosides, kaempferiaosides A and B were isolated from the rhizomes of Kaempferia parviflora (Zingiberaceae) together with 24 known compounds. Their structures including absolute stereochemistry were elucidated on the basis of chemical and spectroscopic evidence. Among the isolates, 5,3'-dihydroxy-3,7,4'-trimethoxyflavone showed higher activity than silybin, a commercial hepatoprotective agent.

A novel sugar ester poacynose (1) was isolated from the flowers of Poacynum hendersonii together with 31 known compounds. The structure of 1 was established mainly on the basis of 1D and 2D NMR spectral data. Among the isolates, several constituents, such as kaempferol 3-O-sophoroside (5), picein (16), and 4-hydroxybenzoic acid 4-O-β-d-glucopyranoside (17) moderately promoted adipogenesis of 3T3-L1 cells. In addition, simultaneous quantitative analysis of eight flavonoid constituents from the flower and leaf parts of P. hendersonii was developed.

The methanolic extract from the leaves of Salacia chinensis collected in Thailand was found to show a protective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. From the methanolic extract, eight new glycosides, named foliachinenosides E, F, G, H, and I, and foliasalaciosides J, K and L, were isolated together with 26 known constituents. The structures of new glycosides were determined on the basis of physicochemical and chemical evidence. In addition, the hepatoprotective effects of the isolated compounds on D-galactosamine-induced cytotoxicity were examined. Among them, lignans, eleutheroside E₂ and 7R,8S-dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside, were found to show the protective effects [inhibition (%) 41.4 ± 3.6 (p < 0.01), 45.5 ± 2.7 (p < 0.01) at 100 µM, respectively].

Five new triterpene saponins perennisosides VIII (1), IX (2), X (3), XI (4), and XII (5) were isolated from the MeOH-eluated fraction of the methanolic extract from the flowers of Bellis perennis. The MeOH-eluted fraction of the methanolic extract from the flowers of B. perennis was found to inhibit gastric emptying in olive oil-loaded mice at a dose of 200 mg/kg, per os (p.o.). The stereostructures of 1-5 were elucidated on the basis of chemical and spectroscopic evidence.

The methanolic extract from fresh stems of Cistanche tubulosa (Orobanchaceae) was found to show hepatoprotective effects against D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. From the extract, three new phenylethanoid oligoglycosides, kankanosides H(1) (1), H(2) (2), and I (3), were isolated together with 16 phenylethanoid glycosides (4-19) and two acylated oligosugars (20, 21). The structures of 1-3 were determined on the basis of spectroscopic properties as well as of chemical evidence. Among the isolates, echinacoside (4, IC(50)=10.2 microM), acteoside (5, 4.6 microM), isoacteoside (6, 5.3 microM), 2'-acetylacteoside (8, 4.8 microM), and tubuloside A (10, 8.6 microM) inhibited D-GalN-induced death of hepatocytes. These five isolates, 4 (31.1 microM), 5 (17.8 microM), 6 (22.7 microM), 8 (25.7 microM), and 10 (23.2 microM), and cistantubuloside B(1) (11, 21.4 microM) also reduced TNF-alpha-induced cytotoxicity in L929 cells. Moreover, principal constituents (4-6) exhibited in vivo hepatoprotective effects at doses of 25-100mg/kg, po.

The MeOH extract from the flowers of Bellis perennis was found to show pancreatic-lipase inhibitory activity (IC50 455 μg/ml). From the extract, seven new triterpene saponins named perennisaponins G (1; IC50 163 μM), H (2; 137 μM), I (3; 147 μM), J (4; 148 μM), K (5; 223 μM), L (6; 81.4 μM), and M (7; 195 μM) were isolated as pancreatic lipase inhibitors. The stereostructures of 1–7 were elucidated on the basis of chemical and spectroscopic evidence.

Four new acylated phenylethanoid oligoglycosides, kankanosides J(1) (1), J(2) (2), K(1) (3), and K(2) (4), were isolated from stems of Cistanche tubulosa (Orobanchaceae) together with isocampneoside I (5). Their structures were elucidated on the basis of chemical and physicochemical evidence. Among them, 3-5 were found to inhibit D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes.

Three iridoid glycosides, kankanosides L, M, and N, and two acyclic monoterpene glycosides, kankanosides O and P, were isolated from fresh stems of Cistanche tubulosa (Orobanchaceae) together with eight iridoid glycosides, five acyclic monoterpene glycosides, three phenylpropanoid glycosides, and four lignan glycosides. Their structures were elucidated on the basis of chemical and physicochemical evidence.

Four novel megastigmanes, neosedumosides I ( 1 ), II ( 2 ), III ( 3 ), and IV ( 4 ) were isolated from the whole plant of Sedum sarmentosum (Crassulaceae). Absolute stereostructures of these constituents were determined on the basis of chemical and physicochemical evidence. Among them, 1 – 3 were found to show lipid accumulation inhibitory activity in HepG2 cells. Furthermore, 2 and 3 were found to also show lipid metabolism-promoting activity.

The methanolic extract from the flowers of Punica granatum L. (Punicaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha, 1 ng/ml)-induced cytotoxicity in L929 cells. By bioassay-guided separation, a new taraxastane-type triterpene, punicanolic acid (1), was isolated from the active fraction (ethyl acetate-soluble fraction) together with four triterpenes (2--5), two galloyl glucoses (6, 7), two flavones (8, 9), and beta-sitosterol. Among the constituents, 1, oleanolic acid (2), maslinic acid (4), 1,2,6-tri-O-galloyl beta-D-glucopyranoside (6), 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl beta-D-glucopyranoside (7), and luteolin (8) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 30 microM.

The methanolic extract from the rhizomes of Boesenbergia rotunda (Zingiberaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha)-induced cytotoxicity in L929 cells (IC(50)=6.1 microg/ml). By bioassay-guided separation, four new prenylcalcones, (+)-krachaizin A (1a), (-)-krachaizin A (1b), (+)-krachaizin B (2a), and (-)-krachaizin B (2b), and four new prenylflavanones, rotundaflavones Ia (3a), Ib (3b), IIa (4a), and IIb (4b), were isolated together with 18 known constituents (5a-7b and 8-19). The structures of eight new compounds were elucidated on the basis of physicochemical evidence. Among them, (+)-krachaizin B (2a), (-)-krachaizin B (2b), (+)-4-hydroxypanduratin A (6a), (-)-4-hydroxypanduratin A (6b), (+)-isopanduratin A (7a), (-)-isopanduratin A (7b), alpinetin (10), cardamonin (14), and 2,6-dihydroxy-4-methoxydihydrochalcone (15) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 10 microM. In addition, 2a, 2b, (+)-panduratins A (5a), (-)-panduratin A (5b), 6a, 7b, and geranyl-2,4-dihydroxy-6-phenylbenzoate (17) were found to show strong inhibitory effects on aminopeptidase N activity.

The 80% aqueous acetone extract from the flowers of Hedychium coronarium was found to show a protective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. On the other hand, two new labdane-type diterpene glycosides, coronalactosides I (1) and II (2), and a new labdane-type trinorditerpene, coronadiene (3), were isolated together with 8 known compounds from the extracts, which were obtained with chloroform and 80% aqueous acetone from the flowers of H. coronarium. The structures of new constituents were elucidated on the basis of chemical and physicochemical evidence. In addition, the principal constituents, coronaririn C and 15-hydroxylabda-8(17),11,13-trien-16,15-olide, displayed hepatoprotective effects, which were stronger than that of the hepatoprotective agent, silybin.

A methanol extract from the rhizomes of Kaempferia parviflora Wall. ex Baker (Zingiberaceae) has shown inhibitory effects against melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells (IC50 = 9.6 μg/mL). Among 25 flavonoids and three acetophenones isolated previously (1-28), several constituents including 5-hydroxy-7,3',4'-trimethoxyflavone (6, IC50 = 8.8 μM), 5,7,3',4'-tetramethoxyflavone (7, 8.6 μM), 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (12, 2.9 μM), and 5-hydroxy-3,7,3',4'-tetramethoxyflavone (13, 3.5 μM) showed inhibitory effects without notable cytotoxicity at the effective concentrations. Compounds 6, 7, 12, and 13 inhibited the expression of tyrosinase, tyrosine-related protein (TRP)-1, and TRP-2 mRNA, which could be the mechanism of their melanogenesis inhibitory activity. In addition, a quantitative analytical method for 12 methoxyflavones (1, 2, 4-11, 13, and 14) in the extract was developed using HPLC. The optimal condition for separation and detection of these constituents were achieved on an ODS column (3 μm particle size, 2.1 mm i.d. × 100 mm) with MeOH-0.1 % aqueous acetic acid solvent systems as the mobile phase, and the detection and quantitation limits of the method were estimated to be 0.08-0.66 ng and 0.22-2.00ng, respectively. The relative standard deviation values of intra- and interday precision were lower than 0.95 and 1.08 %, respectively, overall mean recoveries of all flavonoids were 97.9-102.9 %, and the correlation coefficients of all the calibration curves showed good linearity within the test ranges. For validation of the protocol, extracts of three kinds of the plant's rhizomes collected from different regions in Thailand (Leoi, Phetchabun, and Chiang Mai provinces) were evaluated. The results indicated that the assay was reproducible, precise, and could be readily utilized for the quality evaluation of the plant materials.

Seven novel limonoids, e.g. mexicanolide-type carapanolides R (Ia) and S (Ib) are isolated from the oil of Carapa guianensis.

[structure: see text] Four new dolabellane-type diterpene alkaloids, nigellamines A(1) (1), A(2) (2), B(1) (3), and B(2) (4), were isolated from the seeds of Nigella sativa. Their absolute stereostructures were determined on the basis of chemical and physicochemical evidence. Nigellamines A(1) (1), B(1) (3), and B(2) (4) were found to show potent lipid metabolism promoting activity in primary cultured mouse hepatocytes, and their activities were equivalent to that of a PPAR-alpha agonist, clofibrate.

Six new sesquiterpenes, cyperusols A(1) (1), A(2) (2), B(1) (3), B(2) (4), C (5), and D (6), together with two monoterpenes and 13 sesquiterpenes were isolated from an Egyptian herbal medicine, the whole plants of Cyperus longus. The stereostructures of the new sesquiterpenes were determined on the basis of chemical and physicochemical evidence. In addition, the principal constituents were found to exhibit inhibitory activity on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes.

New dolabellane-type diterpene alkaloids, nigellamines A(3), A(4), A(5), and C, were isolated from the methanolic extract of an Egyptian medicinal food, black cumin (the seeds of Nigella sativa). Their absolute configurations were determined on the basis of chemical and physicochemical evidence. Nigellamines were found to lower triglyceride levels in primary cultured mouse hepatocytes, and in particular, the activity of nigellamine A(5) was equivalent to that of the hypolipidemic agent, clofibrate.

The saponin fraction from the flower buds of Panax notoginseng exhibited protective effect on liver injury induced by d-galactosamine and lipopolysaccharide. From the saponin fraction with hepatoprotective effect, five new dammarane-type triterpene saponins, notoginsenosides-O (1), -P (2), -Q (3), -S (4), and -T (5), were isolated together with nine known protopanaxadiol oligoglycosides. The structures of the new saponins were elucidated on the basis of chemical and physicochemical evidence. The principal dammarane-type triterpene saponins from the roots and flower buds of Panax notoginseng were found to show potent hepatoprotective effects.

The methanolic extract of the roots of Saussurea lappa C larke , a Chinese medicinal herb Saussureae Radix, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Among the constituents from the methanolic extract, two sesquiterpene lactones (costunolide and dehydrocostus lactone) and two amino acid-sesquiterpene conjugates (saussureamines A and B) potently inhibited LPS-induced NO production (IC 50 =1.2–2.8 μM). Saussureamines A and B in addition to costunolide and dehydrocostus lactone did not inhibit iNOS enzyme activity, but they inhibited both induction of inducible NO synthase and activation of nuclear factor-κB in accordance with induction of heat shock protein 72.

The methanolic extract from the flowers of Tilia argentea (linden) was found to show a hepatoprotective effect against d -galactosamine ( d -GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. By bioassay-guided separation using in vitro d -GalN-induced damage to hepatocytes, five flavonol glycosides were isolated as the hepatoprotective constituents of the methanolic extract. Tiliroside, the principal flavonol glycoside, strongly inhibited serum GPT and GOT elevations at doses of 25–100 mg/kg (p.o.) in d -GalN/LPS-treated mice. By comparing the inhibitory effects of tiliroside with those of its components alone, the kaempferol 3-O-β- d -glucopyranoside moiety was found to be essential for the activity, and its effect was suggested to depend on the inhibition of tumor necrosis factor-α (TNF-α) production, decreased sensitivity of hepatocytes to TNF-α, and on the protection of hepatocytes against d -GalN.

Basic inhibitory mechanisms of costunolide and its active component, alpha-methylene-gamma-butyrolactone (alpha-MGBL), on blood-ethanol elevation were investigated in rats. In normal rats, blood-ethanol elevation (30 min later) induced by 20% (v/v) ethanol [5 ml/kg, per os (p.o.)] was strongly inhibited by pretreatment (30 min earlier) with costunolide and alpha-MGBL (50 mg/kg, p.o.). In pylorus-ligated rats given ethanol, blood-ethanol level (30 min) was barely elevated compared with that of normal rats. Neither costunolide nor alpha-MGBL affected the blood-ethanol elevation in pylorus-ligated rats or that induced by intraperitoneal and intraduodenal ethanol administration. Moreover, these compounds given orally induced no irreversible changes in alcohol dehydrogenase activity in rat liver. We continuously investigated the rate of gastric emptying in rats given various test meals. Costunolide and alpha-MGBL suppressed gastric emptying in rats given 20% ethanol and 1% sodium carboxymethyl cellulose. alpha-MGBL (50 mg/kg), but not costunolide, suppressed gastric emptying in 20% glucose-loaded rats. In an in vitro experiment, alpha-MGBL contracted the pylorus strip at a high concentration (20 mM), which was the estimated concentration in the stomach when the substance was given orally in vivo. These findings suggested that alpha-MGBL constricted the pylorus and caused delay of gastric emptying. Moreover, both compounds increased gastric fluid secretion with pepsin and mucus. In conclusion, the inhibitory effects of costunolide and alpha-MGBL on blood-ethanol elevation were based on inhibition of gastric emptying and dilution of the ethanol concentration by the increased gastric fluid.

The hepatoprotective effects of the hot water (SRHW) and methanolic (SRM) extracts from the roots and stems of Salacia reticulata were examined using an oxidative stress-induced liver injury model. Both SRHW and SRM extracts (400 mg/kg, p.o.) significantly suppressed the increase in glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities in carbon tetrachloride (CCl4)-treated mice. These extracts also inhibited CCl4-induced thiobarbituric acid-reactive substance (TBA-RS) formation, which indicates increased lipid peroxidation in the liver. A good correlation (r=0.945, p0.01) was observed between the amount of phenolic compounds in the extracts and their inhibitions of TBA-RS formation. The IC50 values of the extracts on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging were less than 10 microg/ml and the antioxidative activities of six phenolic compounds from the roots of S. reticulata were examined. Mangiferin, (-)-4'-O-methylepigallocatechin, and (-)-epicatechin-(4beta--8)-(-)-4'-O-methylepigallocatechin, which a principal phenolic compounds, showed potent scavenging activity on DPPH radicals and their concentrations required for 50% reduction of 40 microM DPPH radicals were 5.9, 10, and 3.2 microM, respectively. On the other hand, against the CCl4-induced serum GOT and GPT elevations and TBA-RS formation in mice, mangiferin and (-)-4'-O-methylepigallocatechin showed potent activity at a dose of 100 mg/kg, but (-)-epicatechin-(4beta--8)-(-)-4'-O-methylepigallocatechin did not. These results suggest that the antioxidative activity of the principal phenolic compounds is involved in the hepatoprotective activity of S. reticulata.

The 80% aqueous acetone extract of Zedoariae Rhizoma was found to show a protective effect against D-galactosamine (D-GalN)/lipopolysaccharide-induced acute liver injury in mice. To clarify the active compounds, the principal constituents were examined and 11 sesquiterpenes (furanodiene, curdione, neocurdrione, dehydrocurdione, germacrone, 13-hydroxygermacrone, curcumenol, isocurcumenol, aerugidiol, zedoarondiol, and curcumenone) and a diarylheptanoid (curcumin) were found to inhibit the increase in serum aspartate aminotransaminase and alanine aminotransaminase at a dose of 50 mg/kg p.o. in agreement with the previous in vitro studies, except for dehydrocurdione, aerugidiol, and zedoarondiol. In particular, curdione, neocurdione, curcumenol, and isocurcumenol potently inhibited the increase at a dose of 12.5 mg/kg p.o. Furthermore, the eight sesquiterpenes, furanodiene, curdione, neocurdione, dehydrocurdione, germacrone, 13-hydroxygermacrone, curcumenol, and curcumenone, also showed a protective effect against D-GalN/tumor necrosis factor-alpha-induced liver injury in mice at a dose of 50 mg/kg p.o.

A methanol extract from the aerial part of Isodon trichocarpus (Labiatae) demonstrated inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells (IC50 = 1.6 μg/mL). From the extract, nine diterpenoids (1–9) and four triterpenoids (10–13) were isolated. Among the isolates, enmein (1, IC50 = 0.22 μM), isodocarpin (2, 0.19 μM), nodosin (4, 0.46 μM), and oridonin (6, 0.90 μM) showed an inhibitory effect without notable cytotoxicity at the effective concentrations. These diterpenoids (1, 2, 4, and 6) inhibited the expression of tyrosinase, tyrosine-related protein (TRP)-1, and TRP-2 mRNA, which could be the mechanism of melanogenesis inhibitory activity.

A simultaneous quantitative analytical method for 13 stilbenoids including (−)-hopeaphenol (1), (+)-isohopeaphenol (2), hemsleyanol D (3), (−)-ampelopsin H (4), vaticanols A (5), E (6), and G (7), (+)-α-viniferin (8), pauciflorol A (9), hopeafuran (10), (−)-balanocarpol (11), (−)-ampelopsin A (12), and trans-resveratrol 10-C-β-d-glucopyranoside (13), and two dihydroisocoumarins, phayomphenols A1 (14) and A2 (15) in the extract of Shorea roxburghii (dipterocarpaceae) was developed. According to the established protocol, distributions of these 15 polyphenols (1–15) in the bark and wood parts of S. roxburghii and a related plant Cotylelobium melanoxylon were evaluated. In addition, the principal polyphenols (1, 2, 8, 13–15) exhibited hepatoprotective effects against d-galactosamine (d-galN)/lipopolysaccharide (LPS)-induced liver injury in mice at a dose of 100 or 200 mg/kg, p.o. To characterize the mechanisms of action, the isolates were examined in in vitro studies assessing their effects on (i) d-GalN-induced cytotoxicity in primary cultured mouse hepatocytes; (ii) LPS-induced nitric oxide (NO) production in mouse peritoneal macrophages; and (iii) tumor necrosis factor-α (TNF-α)-induced cytotoxicity in L929 cells. The mechanisms of action of these polyphenols (1, 2, and 8) were suggested to be dependent on the inhibition of LPS-induced macrophage activation and reduction of sensitivity of hepatocytes to TNF-α. However, none of the isolates reduced the cytotoxicity caused by d-GalN.

An 80% aqueous acetone extract of Cassia auriculata leaves was found to show a protective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. From the 80% aqueous acetone extract, we isolated a new benzocoumarin glycoside, avaraoside I (1), and a new flavanol dimer, avaraol I (2), together with 29 known constituents. The structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. In addition, three isolated compounds, pseudosemiglabrin (15, 0.0011%), (2S)-7,4'-dihydroxyflavan(4β→8)-catechin (22, 0.00075%), and (2S)-7,4'-dihydroxyflavan(4β→8)-gallocatechin (23, 0.092%), displayed hepatoprotective effects equivalent to that of the hepatoprotective agent, silybin.

The aqueous acetone extract of Zedoariae Rhizoma was found to show inhibitory effects on contractions induced by high concentrations of potassium cation (K+) in isolated rat aortic strips. From the extract, two new carabrane-type sesquiterpenes, curcarabranols A and B, were isolated together with a few carabrane-type sesquiterpenes, such as curcumenone and 4S-dihydrocurcumenone. Their absolute stereostructures were determined on the basis of chemical and physicochemical evidence, which included the application of the modified Mosher's method and chemical conversion from curcumenone to curcarabranols A and B. In addition, several sesquiterpenes and diarylheptanoids (e.g. germacrone, glechomanolide, isocurucmenol, β-eudesmol, and β-dictyopterol) showed potent inhibitory effects on contractions induced by high concentrations of K+ in isolated rat aortic strips (inhibition >80% at 100 μM), while they did not inhibit norepinephrine-induced contractions, so that the vasorelaxant activities of these sesquiterpenes were presumed to be dependent on their calcium channel-blocking activity.

New carabrane-type sesquiterpene lactones, curcumenolactones A, B, and C, were isolated from the 80% aqueous acetone extract of Zedoariae Rhizoma (Zingiberaceae), together with 41 sesquiterpenes and two diarylheptanoids. The absolute stereostructures of curcumenolactones A, B, and C were determined on the basis of physicochemical evidence, which included nuclear Overhauser effect (NOE) and circular dichroic (CD) spectroscopic analyses. Curcumenone, a principal carabrane-type sesquiterpene from Zedoariae Rhizoma, was found to show potent protective effect on D-galactosamine/lipopolysaccharide-induced acute liver injury in mice. In addition, curcumenolactones A and B and the other constituents showed protective effect on D-galactosamine-induced cytotoxicity in primary cultured rat hepatocytes.

A new ionone glucoside, pisumionoside, a phenethyl glycoside, sayaendoside, and two acylated flavonol oligoglycosides, pisumflavonosides I and II, were isolated from the young seedpods of garden peas, Pisum sativum L., together with quercetin and kaempferol 3-O-(6-O-trans-p-coumaroyl)-beta-D-glucopyranosyl (1--2)-beta-D-glucopyranosyl (1--2)-beta-D-glucopyranosides and quercetin and kaempferol 3-sophorotriosides. The structures of pisumionoside, sayaendoside, and pisumflavonosides I and II were determined on the basis of chemical and physicochemical evidence, respectively. Quercetin 3-sophorotrioside, a principle component, was found to show protective effects on liver injury induced by D-galactosamine and lipopolysaccharide and by carbon tetrachloride in mice.

Triterpene glycoside adonitol esters, scorzonerosides A, B, and C, were isolated from Chinese Bupleuri Radix, the roots of Bupleurum scorzonerifolium . Their absolute stereostructures were elucidated on the physicochemical and chemical evidence, which included the synthesis of the adonitol moiety from d -ribose. Scorzonerosides A, B, and C were found to show hepatoprotective effect on liver injury induced by d -galactosamine and lipopolysaccharide in mice.

New hepatoprotective saponins, bupleurosides III, VI, IX, and XIII, were isolated from Chinese Bupleuri Radix, the roots of Bupleurum scorzonerifolium Willd ., together with nine new and sixteen known saponins. The structures of bupleurosides III, VI, IX, and XIII were elucidated on the basis of chemical and physicochemical evidence. By examination of the structure requirements in saponins for the protective effect on the d -galactosamine-induced cytotoxicity in primary cultured rat hepatocytes, the 11-oxygen function, the 16β-hydroxyl group, and the 3-O-diglycoside moiety were found to be essential to exerting the hepatocytoprotective activity.

We have investigated the effects of escins Ia, Ib, IIa, and IIb isolated from horse chestnut, the seeds of Aesculus hippocastanum L. and desacylescins I and II obtained by alkaline hydrolysis of escins on acute inflammation in experimental animal models, and some structure-requirements of escins for the activity was obtained.

A methanol extract from the tuberous roots of Potentilla anserina (Rosaceae) exhibited hepatoprotective effects against d-galactosamine (d-GalN)/lipopolysaccharide-induced liver injuries in mice. Six triterpene 28-O-monoglucopyranosyl esters, potentillanosides A-F, were isolated from the extract along with 32 known compounds, including 15 triterpenes. The structures of potentillanosides A-F were determined on the basis of spectroscopic properties and chemical evidence. Four ursane-type triterpene 28-O-monoglycosyl esters, potentillanoside A (IC50=46.7μM), 28-O-β-d-glucopyranosyl pomolic acid (IC50=9.5μM), rosamutin (IC50=35.5μM), and kaji-ichigoside F1 (IC50=14.1μM), inhibited d-GalN-induced cytotoxicity in primary cultured mouse hepatocytes. Among these four triterpenes, potentillanoside A, rosamutin, and kaji-ichigoside F1 exhibited in vivo hepatoprotective effects at doses of 50-100mg/kg, p.o. The mode of action was ascribable to the reduction in cytotoxicity caused by d-GalN.

Acylated oleanane-type triterpene saponins, namely chakasaponins I (1) and II (2), floratheasaponin A (3), and their analogs, together with catechins—including (–)-epigallocatechin 3-O-gallate (4), flavonoids, and caffeine—have been isolated as characteristic functional constituents from the extracts of “tea flower”, the flower buds of Camellia sinensis (Theaceae), which have common components with that of the leaf part. These isolates exhibited antiproliferative activities against human digestive tract carcinoma HSC-2, HSC-4, MKN-45, and Caco-2 cells. The antiproliferative activities of the saponins (1–3, IC50 = 4.4–14.1, 6.2–18.2, 4.5–17.3, and 19.3–40.6 µM, respectively) were more potent than those of catechins, flavonoids, and caffeine. To characterize the mechanisms of action of principal saponin constituents 1–3, a flow cytometric analysis using annexin-V/7-aminoactinomycin D (7-AAD) double staining in HSC-2 cells was performed. The percentage of apoptotic cells increased in a concentration-dependent manner. DNA fragmentation and caspase-3/7 activation were also detected after 48 h. These results suggested that antiproliferative activities of 1–3 induce apoptotic cell death via activation of caspase-3/7.

A quantitative analytical method has been developed for four alkaloids (1–4), identified as constituents responsible for the melanogenesis inhibitory activity of the extracts of wintersweet, the flower buds of Chimonanthus praecox (L.) Link (Calycanthaceae). Concurrently, a quantitative analytical protocol has been developed for five flavonoids (5–9), which also exhibited inhibitory activity. To approve the validity of the developed protocols, five extracts of the flower buds collected in Chinese market were evaluated. The optimum conditions of separation and detection of these alkaloids (1–4) and flavonoids (5–9) were achieved on a common ODS column using a MeOH-H2O mobile phase with different additives [Et2NH for alkaloids (1–4); acetic acid for flavonoids (5–9)]. The results indicated that these assays were reproducible and precise, and could be readily utilized for evaluation of the melanogenesis inhibitory activity of wintersweet on the basis of the content of the functional species. The principal flavonoid constituents (5–9) also exhibited lipid accumulation inhibitory activity.

With the aid of an in silico method, α-glucosidase inhibitors with far more potent activities than salacinol (1), a potent natural α-glucosidase inhibitor isolated from an Ayurvedic traditional medicine Salacia reticulata, have been developed.

Two new phenolic glycosides, kaempferiaosides A and B were isolated from the rhizomes of Kaempferia parviflora (Zingiberaceae) together with 24 known compounds. Their structures including absolute stereochemistry were elucidated on the basis of chemical and spectroscopic evidence. Among the isolates, 5,3'-dihydroxy-3,7,4'-trimethoxyflavone showed higher activity than silybin, a commercial hepatoprotective agent.

A methanol extract of the flowers of Mammea siamensis (Calophyllaceae) was found to inhibit nitric oxide (NO) production in lipopolysaccharide-activated RAW264.7 cells. From the extract, two new geranylated coumarins, mammeasins A (1) and B (2), were isolated together with 17 known compounds including 15 coumarins. The structures of 1 and 2 were determined on the basis of their spectroscopic properties as well as of their chemical evidence. Among the isolates, 1 (IC(50) = 1.8 μM), 2 (6.4 μM), surangins B (3, 5.0 μM), C (4, 6.8 μM), and D (5, 6.2 μM), kayeassamins E (7, 6.1 μM), F (8, 6.0 μM), and G (9, 0.8 μM), mammea A/AD (11, 1.3 μM), and mammea E/BB (16, 7.9 μM) showed NO production inhibitory activity. Compounds 1, 9, and 11 were found to inhibit induction of inducible nitric oxide synthase (iNOS). With regard to mechanism of action of these active constituents (1, 9, and 11), suppression of STAT1 activation is suggested to be mainly involved in their suppression of iNOS induction.

Two new phenolic glycosides, kaempferiaosides A and B were isolated from the rhizomes of Kaempferia parviflora (Zingiberaceae) together with 24 known compounds. Their structures including absolute stereochemistry were elucidated on the basis of chemical and spectroscopic evidence. Among the isolates, 5,3'-dihydroxy-3,7,4'-trimethoxyflavone showed higher activity than silybin, a commercial hepatoprotective agent.

Eight new glycosides, foliachinenoside G (I), F (V), E (VI), I (VIIa), H (VIIb) and foliasalacioside J (II), K (III) and L (IV) are isolated along with 26 known constituents from the methanolic extract of title shrub leaves.

The methanol extract from the bark of Shorea roxburghii (Dipterocarpaceae, "Phayom" in Thai) was found to suppress plasma triglyceride elevation in olive oil-treated mice, and also to inhibit pancreatic lipase activity (IC(50) = 31.6 μg/ml). From the extract, two new 3-acetyl-4-phenyl-3,4-dihydroisocoumarins, phayomphenols A(1) (1) and A(2) (2) were isolated, together with 22 known compounds. The structures of 1 and 2 were elucidated on the basis of chemical and spectroscopic evidence, including X-ray crystallographic analysis. Among the isolates, several oligostilbenoids, including (-)-hopeaphenol (3) and (+)-isohopeaphenol (4), showed inhibitory effects on plasma triglyceride elevation at a dose of 200 mg/kg p.o. and pancreatic lipase inhibitory activity (IC(50) = 32.9 and 26.5 μM, respectively).