β‐secretase inhibitory effects of furanocoumarins from the root of Angelica dahurica

In the course of screening antidementia agents from natural products, five β‐secretase (BACE1) inhibitors were isolated from the root extract of Angelica dahurica (Umbelliferae). They were identified as furanocoumarins, isoimperatorin (1), imperatorin (2), (+)‐oxypeucedanin (3), (+)‐byakangelicol (4) and (+)‐byakangelicin (5). Among them, compounds 2 and 4 showed significant inhibitory activity against β‐secretase (BACE1) with IC₅₀ values of 91.8 ± 7.5 and 104.9 ± 2.4 μM , respectively. Compounds 1‐5 inhibited BACE1 activity in a dose‐dependent manner. Copyright © 2009 John Wiley & Sons, Ltd.     

Multifunctional Activity of Polyphenolic Compounds Associated with a Potential for Alzheimer's Disease Therapy from Ecklonia cava

Five polyphenols were isolated and purified from a brown alga Ecklonia cava. These compounds showed diverse biological activities such as antioxidative, antiinflammatory, and enzyme inhibitory activities. This led us to investigate the potential of these compounds as Alzheimer's disease drugs. All of the compounds showed moderate acetylcholinesterase inhibitory activity in a micromolar range (IC₅₀ from 16.0 to 96.3 μM). For butyrylcholinesterase, a new target for the treatment of Alzheimer's disease, phlorofucofuroeckol‐A (PFF‐A), showed a particularly potent inhibitory activity (IC₅₀ 0.95 μM), which is over 100‐fold greater than for acetylcholinesterase. These compounds inhibited glycogen synthase kinase 3 beta, which is related to the formation of hyperphosphorylated tau and generation Aβ. Bieckol and PFF‐A inhibited amyloid precursor protein biosynthesis. PFF‐A also showed very strong β‐secretase inhibitory activity with IC₅₀ of submicromole. These results render these compounds as interesting potential drug candidates for Alzheimer's disease. Copyright © 2015 John Wiley & Sons, Ltd.     

Antihyperlipidemic Components of Cassia auriculata Aerial Parts: Identification Through In Vitro Studies

Cassia auriculata (Caesalpiniaceae) is a common Asian beverage and medicinal plant widely used in tradition medicine for diabetes, hyperlipidemia and various other disease conditions. Previous studies on crude extracts of C. auriculata have documented the scientific basis for some of its traditional medicinal uses. The present study investigates the antilipase activity of the ethanol extract of the aerial parts along with the previously isolated compounds (kaempferol‐3‐O‐rutinoside, rutin, kaempferol, quercetin and luteolin). The crude extract displayed inhibitory activity against pancreatic lipase with IC₅₀ of 6.0 ± 1.0 µg/mL. The most active antilipase compound was kaempferol‐3‐O‐rutinoside with IC₅₀ value (2.9 ± 0.50 μM) only about twice weaker than the standard antilipase drug, orlistat (IC₅₀ = 1.45 ± 0.26 μM). Luteolin, quercetin and rutin were found to be weak pancreatic lipase inhibitors (IC₅₀ over 100 μM), whereas kaempferol showed no activity up to 250 μM. The antihyperlipidemic effect of C. auriculata could be attributed to direct lipase inhibitory effect of the plant constituents. Copyright © 2012 John Wiley & Sons, Ltd.     

Anti‐allergic activity of principles from the roots and heartwood of caesalpinia sappan on antigen‐induced β‐hexosaminidase release

The dichloromethane extract of the roots and heartwood of Caesalpinia sappan exhibited potent inhibitory activity against β‐hexosaminidase release as marker of degranulation in rat basophilic leukemic (RBL‐2H3) cells, with inhibition of 98.7% and 87.5% at concentration of 100 µg/ml, respectively. These extracts were further separated by chromatographic techniques to give two chalcones and seven homoisoflavones. Among the compounds tested, sappanchalcone (2) possessed the most potent effect against allergic reaction in RBL‐2H3 cells with an inhibitory concentration (IC₅₀) value of 7.6 µM, followed by 3‐deoxysappanchalcone (1, IC₅₀ = 15.3 µM), whereas other compounds showed moderate and mild effects. The results suggested the following structural requirements of chalcones (1 and 2) and homoisoflavones (3‐9) for anti‐allergic activity: (i) chalcone exhibited higher activity than homoisoflavone (ii) vicinal hydroxylation at B‐ring of chalcone conferred higher activity than one hydroxylation; and (iii) for homoisoflavone, the hydroxyl groups at C‐3 and C‐4 positions decreased the activity. This is the first report of C. sappan for anti‐allergic activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Antiplasmodial and cytotoxic activity of phloroglucinol derivatives from Hypericum erectum thunb

The chloroform extracts of whole plants of Hypericum erectum were investigated for antiplasmodial activity against chloroquine‐sensitive strains of Plasmodium falciparum. Five phloroglucinol derivatives, otogirin (1), otogirone (2), erectquione A (3), erectquione B (4), and erectquione C (5) were isolated from the whole plants of H. erectum. Also, five compounds were evaluated for in vitro antiplasmodial activities as well as their cytotoxic potential on SK‐OV‐3 cancer cell line cells. Compounds 2, 4 showed notable growth inhibitory activity against chloroquine‐sensitive strains of Plasmodium falciparum with IC₅₀ values from 5.6 and 7.2 μM. This compound showed no significant cytotoxicity (IC₅₀ > 150 μM) evaluated using SK‐OV‐3 cancer cell line cells. Copyright © 2010 John Wiley & Sons, Ltd.     

Compounds with tyrosinase inhibition, elastase inhibition and DPPH radical scavenging activities from the branches of Distylium racemosum Sieb. et Zucc

Twenty compounds were isolated from the ethanol extract of Distylium racemosum branches and their inhibitory activities on tyrosinase, elastase and free radicals evaluated. The isolated compounds were identified as dibenzofurans (1–4), abscisic acid (5), 6′‐O‐galloylsalidroside (6), catechin derivatives (7–11), gallic acid derivatives (12–14), tyrosol (15), flavonoids (16–18), lupeol (19) and 1,2,3,6‐tetragalloylglucose (20). For study of tyrosinase inhibition activities, when compared with arbutin (IC₅₀ 48.8 μg/mL), four compounds (8, 11, 13, 17) showed higher activities, with IC₅₀ values of 4.8, 30.2, 40.5 and 37.7 μg/mL, respectively. For the elastase inhibition test, dibenzofuran 1 showed greater activity than the positive control, oleanolic acid (IC₅₀ 9.7 μg/mL), with an IC₅₀ of 7.7 μg/mL. In the studies on DPPH radical scavenging activities, five compounds (11, 12, 13, 14, 15) showed higher activities than ascorbic acid (IC₅₀ 5.0 μg/mL), with IC₅₀ values of 4.6, 3.9, 2.9, 3.8 and 4.7 μg/mL, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Pentacyclic Triterpenoids from Spikes of Prunella vulgaris L. Inhibit Glycogen Phosphorylase and Improve Insulin Sensitivity in 3T3‐L1 Adipocytes

Phytochemical investigation of methanol extract from the spikes of Prunella vulgaris L. led to the isolation of two new pentacyclic triterpenoid glycosides Vulgasides I (1) and II (2) along with 13 known compounds (3–15). Their structures were established on the basis of nuclear magnetic resonance (1D and 2D) and mass spectroscopic data analysis. All the isolated compounds were screened for glycogen phosphorylase inhibitory activity and also evaluated for their effect on insulin sensitivity in 3T3‐L1 adipocytes. Two new compounds (1, 2) did not demonstrate the glycogen phosphorylase inhibitory activity, but other compounds (3–11) exhibited varying degrees of glycogen phosphorylase inhibitory activity with IC₅₀ values in the range from 30.69 to 68.85 μM. Compounds 3, 6, 7, 11, and 13 demonstrated markedly increased insulin‐mediated glucose consumption in 3T3‐L1 adipocytes. Copyright © 2014 John Wiley & Sons, Ltd.     

Antiplasmodial and cytotoxic activity of khellactone derivatives from Angelica purpuraefolia chung

The methanolic extract of the rhizomes parts of Agelica purpuraefolia was investigated for its activity against chloroquine‐sensitive strains of Plasmodium falciparum using the parasite lactate dehydrogenase assay method. Two natural khellactone, (+)‐4′‐Decanoyl‐cis‐khellactone (1) and (+)‐3′‐Decanoyl‐cis‐khellactone (2) were isolated from the rhizomes parts of A. purpuraefolia. Two compounds were evaluated for in vitro antiplasmodial activities as well as their cytotoxic potential on SK‐OV‐3 cancer cell line cells. Compounds 1, 2 showed notable growth inhibitory activity against chloroquine‐sensitive strains of Plasmodium falciparum with IC₅₀ values from 1.5 and 2.4 μM. This compound showed no significant cytotoxicity (IC₅₀ > 100 μM) evaluated using SK‐OV‐3 cancer cell line cells. This is the first report on the antiplasmodial activity of the compounds from A. purpuraefolia. Copyright © 2009 John Wiley & Sons, Ltd.     

Phytochemical and Pharmacological Investigations on Nymphoides indica Leaf Extracts

Nymphoides indica (L.) Kuntze (Menyanthaceae) is traditionally used in the Indian subcontinent. However, scientific data reporting its constituents are poor. This study aimed at evaluating its phytochemical constituents and various biological activities. Phytochemical investigations of the extracts and fractions resulted in the isolation of 5 lipophilic compounds, i.e. azelaic (nonanedioic) acid (1) and 4‐methyl‐heptanedioic acid (3), hexadecanoic (2) and stearic acid (5) and the fatty alcohol hexadecanol (4); 3 seco‐iridoids, i.e. 7‐epiexaltoside (6), 6″,7″‐dihydro‐7‐epiexaltoside (7) and menthiafolin (8); 3 flavonoids, i.e. 3,7‐di‐O‐methylquercetin‐4′‐O‐β‐glucoside (9), 3‐O‐methylquercetin‐7‐O‐β‐glucoside (10) and 3,7‐di‐O‐methylquercetin (11); scopoletin (12) and ferulic acid (13); and the monoterpenoids foliamenthoic acid (14) and 6,7‐dihydrofoliamenthoic acid methyl ester (15). Compounds 1–5 showed moderate antimicrobial activities, whereas compound 9 presented mild antiprotozoal activities against Trypanosoma brucei (IC₅₀ 8 μM), Leishmania infantum (IC₅₀ 32 μM) and Trypanosoma cruzi (IC₅₀ 30 μM). Antiglycation activity was shown by compounds 7 (IC₅₀ 0.36 mM), 10 (IC₅₀ 0.42 mM) and 15 (IC₅₀ 0.61 mM). Finally α‐glucosidase inhibition was shown by compounds 7, 9, 11 and 13–15. It could be concluded that N. indica leaf extracts possess mild to moderate antimicrobial, antiprotozoal, antioxidant and antidiabetic activities. Copyright © 2016 John Wiley & Sons, Ltd.     

Artepillin C and Other Herbal PAK1‐blockers: Effects on Hair Cell Proliferation and Related PAK1‐dependent Biological Function in Cell Culture

PAK1 (RAC/CDC42‐activated kinase 1) is the major oncogenic kinase, and a number of herbal PAK1‐blockers such as propolis and curcumin have been shown to be anti‐oncogenic and anti‐melanogenic as well as anti‐alopecia (promoting hair growth). Previously, we found several distinct PAK1‐inhibitors in Okinawa plants including Alpinia zerumbet (alpinia). Thus, here, we tested the effects of these herbal compounds and their derivatives on the growth of cancer or normal hair cells, and melanogenesis in cell culture of A549 lung cancer, hair follicle dermal papilla cell, and B16F10 melanoma. Among these herbal PAK1‐inhibitors, cucurbitacin I from bitter melon (Goya) turned out to be the most potent to inhibit the growth of human lung cancer cells with the IC₅₀ around 140 nM and to promote the growth of hair cells with the effective dose around 10 nM. Hispidin, a metabolite of 5,6‐dehydrokawain from alpinia, inhibited the growth of cancer cells with the IC₅₀ of 25 μM as does artepillin C, the major anti‐cancer ingredient in Brazilian green propolis. Mimosine tetrapeptides (MFWY, MFYY, and MFFY) and hispidin derivatives (H1–3) also exhibited a strong anti‐cancer activity with the IC₅₀ ranging from 16 to 30 μM. Mimosine tetrapeptides and hispidin derivatives strongly suppressed the melanogenesis in melanoma cells. Copyright © 2015 John Wiley & Sons, Ltd.     

长穗桑中的α-葡萄糖苷酶抑制剂成分研究

 目的 研究长穗桑中具有α-葡萄糖苷酶抑制活性的化学成分。方法 采用各种离子交换树脂对长穗桑水提取物进行分离纯化,通过NMR、MS等波谱分析手段鉴定化合物结构。结果 从长穗桑水提取物中分离到11个化合物,其中7个多羟基生物碱类化合物,2个酰胺类化合物,1个氨基酸以及甜菜碱。分别鉴定为1-deoxynojirimycin (1),fagomine (2),3-epi-fagomine (3),1,4-dideoxy-1,4-imino-D-arabinitol (4),2-O-α-D-galactopyranosyl-1-deoxynojirimycin (5),4-O-β-D-glucopyranosyl-fagomine (6),1,4-dideoxy-1,4-imino-(2-O-β-D-glucopyranosyl)-D-arabinitol (7),(2S)-citrullinamide (8),grateloupinamide (9),天冬氨酸(10),甜菜碱(11)。化合物1~10分别进行了α-葡萄糖苷酶抑制活性筛选。结论 化合物1~11均为首次从该植物中分离得到。4个多羟基生物碱(1,5~7)以及1个酰胺类化合物(9)有较强的α-葡萄糖苷酶抑制活性,其中化合物1的IC₅₀为0.07 μmol·L^-1;化合物5的IC₅₀为0.39 μmol·L^-1,与阳性对照阿卡波糖(acarbose,IC₅₀=0.52 μmol·L^-1)相当;化合物6,7,9的IC₅₀值在1~5 μmol·L^-1。     

Antiparasitic activity of C-geranyl flavonoids from Mimulus bigelovii

Bioactivity‐directed fractionation of the MeOH fraction of the extract of Mimulus bigelovii by means of an axenic Leishmania amastigote assay and chromatographic techniques resulted in the isolation of four C‐geranyl flavanones, diplacone (1), 3′‐O‐methyldiplacone (2), 4′‐O‐methyldiplacone (3), 3′‐O‐methyldiplacol (4), together with a geranylated flavone, cannflavin A (5). These compounds were separated from M. bigelovii for the first time. All compounds showed moderate antileishmanial activity against axenic Leishmania donovani amastigotes with IC₅₀ values ranging from 4.8 to 14.6 μg/mL. The compounds were also tested against the related kinetoplastid parasite Trypanosoma brucei brucei and they showed activity with IC₅₀ values ranging from 1.4 to 7.2 μg/mL. Copyright © 2011 John Wiley & Sons, Ltd.     

Antiviral and anticancer activities of 13(E)‐labd‐13‐ene‐8α,15‐diol isolated from Brachyglottis monroi

The antiviral activity of 13(E)‐labd‐13‐ene‐8α,15‐diol (1), isolated from Brachyglottis monroi, was examined against human rhinovirus 2 (HRV2) and 3 (HRV3), and the anticancer activity on human cancer cells (A549 and Hep2). Compound (1) showed strong anti‐HRV2 and HRV3 activity with a 50% inhibitory concentration (IC₅₀) of 2.68 and 0.87 µg/mL, respectively, and a 50% cytotoxicity concentration (CC₅₀) of 59.45 µg/mL. Ribavirin only showed anti‐HRV3 activity with an IC₅₀ of 30.48 µg/mL and a CC₅₀ > 100 µg/mL. The addition of compound (1) to HRV‐infected HeLa cells directly reduced the formation of visible cytopathic effect (CPE) and it directly interacted with HRV particles. Furthermore, A549 and Hep2 cells incubated with 32 µg/mL of compound (1) for 48 h exhibited antilung and antilaryngeal cancer activities, with a viability of less than 50%. These results suggest that compound (1) may be used as a potential antiviral and anticancer agent. Copyright © 2009 John Wiley & Sons, Ltd.     

Anti‐HIV‐1 Integrase Activity and Molecular Docking Study of Compounds from Caesalpinia sappan L.

Caesalpinia sappan L. (Caesalpiniaceae) has been traditionally used as blood tonic, expectorant, and astringent by boiling with water. Searching for HIV‐1 integrase (IN) inhibitors from this plant is a promising approach. The EtOH extract of C. sappan and its isolated compounds were tested for their anti‐HIV‐1 IN effect using the multiplate integration assay, and the active compounds were determined for their mechanisms by molecular docking technique. Extraction from the heartwoods and roots of C. sappan led to the isolation of nine compounds. Among the compounds tested, sappanchalcone (2) displayed the strongest effect against HIV‐1 IN with an IC₅₀ value of 2.3 μM followed by protosappanin A (9, IC₅₀ = 12.6 μM). Structure‐activity relationships of compounds from C. sappan were found, in which the vicinal hydroxyl moiety were essential for anti‐HIV‐1 IN effect of compounds 2 and 9 by binding with the amino acid residues Gln148 and Thr66 in the core domain of the HIV‐ 1 IN enzyme, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Anti‐platelet Activity of Erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan from Myristica fragrans

Platelets play a critical role in pathogenesis of cardiovascular disorders and strokes. The inhibition of platelet function is beneficial for the treatment and prevention of these diseases. In this study, we investigated the anti‐platelet activity of erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan (EATN), a neolignan isolated from Myristica fragrans, using human platelets. EATN preferentially inhibited thrombin‐ and platelet‐activating factor (PAF)‐induced platelet aggregation without affecting platelet damage in a concentration‐dependent manner with IC₅₀ values of 3.2 ± 0.4 and 3.4 ± 0.3 μM, respectively. However, much higher concentrations of EATN were required to inhibit platelet aggregation induced by arachidonic acid. EATN also inhibited thrombin‐induced serotonin and ATP release, and thromboxane B₂ formation in human platelets. Moreover, EATN caused an increase in cyclic AMP (cAMP) levels and attenuated intracellular Ca²⁺ mobilization in thrombin‐activated human platelets. Therefore, we conclude that the inhibitory mechanism of EATN on platelet aggregation may increase cAMP levels and subsequently inhibit intracellular Ca²⁺ mobilization by interfering with a common signaling pathway rather than by directly inhibiting the binding of thrombin or PAF to their receptors. This is the first report of the anti‐platelet activity of EATN isolated from M. fragrans. Copyright © 2013 John Wiley & Sons, Ltd.     

Chemical Constituents of Euonymus alatus (Thunb.) Sieb. and Their PTP1B and α‐Glucosidase Inhibitory Activities

Phytochemical study on the corks of Euonymus alatus resulted in the isolation of a novel 3‐hydroxycoumarinflavanol (23), along with ten triterpenoids (1–10), ten phenolic derivatives (11–20), and two flavonoid glycosides (21 and 22). Their structures were determined by extensive 1D and 2D‐nuclear magnetic resonance spectroscopic and mass spectrometry data analysis. Furthermore, their inhibitory effects against the protein tyrosine phosphatases 1B (PTP1B) and α‐glucosidase enzyme activity were evaluated. Compounds 6, 7, 9, 15, 19, and 23 were non‐competitive inhibitors, exhibiting most potency with IC₅₀ values ranging from 5.6 ± 0.9 to 18.4 ± 0.3 µm , against PTP1B. Compound 3 (competitive), compounds 5 and 15 (mixed‐competitive) displayed potent inhibition with IC₅₀ values of 15.1 ± 0.7, 23.6 ± 0.6 and 14.8 ± 0.9 µm , respectively. Moreover, compounds 15, 20, and 23 exhibited potent inhibition on α‐glucosidase with IC₅₀ values of 10.5 ± 0.8, 9.5 ± 0.6, and 9.1 ± 0.5 µm , respectively. Thus, these active ingredients may have value as new lead compounds for the development of new antidiabetic agents. Copyright © 2015 John Wiley & Sons, Ltd.     

Anti‐complement activity of isolated compounds from the roots of Clerodendrum bungei Steud.

To determine the anti‐complement activity of natural diterpenes, chromatographic separation of the acetone‐soluble fraction from the roots of Clerodendrum bungei (Verbenaceae) led to the isolation of five diterpenoids. An acetone‐soluble extract of the roots of C. bungei exhibited significant anti‐complement activity on the classical pathway complement system, which was expressed as total hemolytic activity. Five compounds isolated from the roots of C. bungei, namely 12‐O‐β‐d ‐glucopyranosyl‐3,11,16‐trihydroxyabieta‐8,11,13‐triene (1), 3,12‐O‐β‐d ‐diglucopyranosyl‐11,16‐dihydroxyabieta‐8,11,13‐triene (2), ajugaside A (3), uncinatone (4) and 19‐hydroxyteuvincenone F (5). Compounds 1, 2, 3, 4 and 5 showed inhibitory activity against complement system with 50% inhibitory concentrations (IC₅₀) values of 24 µm , 138 µm , 116 µm , 87 µm and 232 µm . Among the compounds tested, 1 showed the most potent anti‐complement activity (IC₅₀, 24 µm ). Copyright © 2010 John Wiley & Sons, Ltd.     

Extracts from Epilobium sp. Herbs,Their Components and Gut Microbiota Metabolites of Epilobium Ellagitannins,Urolithins, Inhibit Hormone‐Dependent Prostate Cancer Cells‐(LNCaP) Proliferation and PSA Secretion

Extracts from Epilobium sp. herbs have been traditionally used in the treatment of prostate‐associated ailments. Our studies demonstrated that the extracts from Epilobium angustifolium, Epilobium parviflorum and Epilobium hirsutum herbs are potent prostate cancer cells (LNCaP) proliferation inhibitors with IC₅₀ values around 35 µg/ml. The tested extracts reduced prostate specific antigen (PSA) secretion (from 325.6 ± 25.3 ng/ml to ~90 ng/ml) and inhibited arginase activity (from 65.2 ± 1.1 mUnits of urea/mg of protein to ~40 mUnits of urea/mg protein). Selected constituents of extracts (oenothein B, quercetin‐3‐O‐glucuronide, myricetin‐3‐O‐rhamnoside) were proven to be active in relation to LNCaP cells. However, oenothein B was the strongest inhibitor of cells proliferation (IC₅₀ = 7.8 ± 0.8 μM), PSA secretion (IC₅₀ = 21.9 ± 3.2 μM) and arginase activity (IC50 = 19.2 ± 2.0 μM). Additionally, ellagitannins from E. hirustum extract were proven to be transformed by human gut microbiota into urolithins. Urolithin C showed the strongest activity in the inhibition of cell proliferation (IC₅₀ = 35.2 ± 3.7 μM), PSA secretion (reduced PSA secretion to the level of 100.7 ± 31.0 ng/ml) and arginase activity (reduced to the level of 27.9 ± 3.3 mUnits of urea/mg of protein). Results of the work offer an explanation of the activity of Epilobium extracts and support the use of Epilobium preparations in the treatment of prostate diseases. Copyright © 2013 John Wiley & Sons, Ltd.