In vitro metabolism in Sprague-Dawley rat liver microsomes of forsythoside A in different compositions of Shuang-Huang-Lian

Shuang–Huang–Lian (SHL), a traditional Chinese formula containing Lonicerae japonicae flos (LJF), Scutellariae radix (SR) and Forsythiae fructus (FF), is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. Forsythoside A is one of the main active ingredients in Forsythiae fructus, a key herb in SHL. In the present study, effects of different compositions in SHL on the in vitro metabolism in Sprague–Dawley rat liver microsomes of forsythoside A were investigated. The observations from Sprague–Dawley rat liver microsomes in the presence of β-NADPH or UDPGA that forsythoside A may be the substrates of CYP3A4, CYP2C9, CYP1A2, UGT1A6, UGT1A3, UGT1A1 and UGT1A9; Chlorogenic acid may be the substrates of CYP3A4, CYP2C9, CYP1A2, CYP2C19, UGT1A6, UGT1A3 and UGT1A1; Baicalin may be the substrates of CYP3A4, CYP2C19, CYP1A2, UGT1A9, UGT1A1 and UGT1A3; Baicalein may be the substrates of CYP3A4, CYP2E1 and UGT1A6. It was also found that the residue of forsythoside A in SHL, FF + LJF and FF + SR was greatly increased compared with that in FF in Sprague–Dawley rat liver microsomes in the presence of β-NADPH or UDPGA, which indicated that the metabolism of forsythoside A in SHL may be influenced by chlorogenic acid in LJF acting on the CYP3A4, CYP2C9, CYP1A2, UGT1A6, UGT1A3 and UGT1A1; baicalin in SR acting on the CYP3A4, CYP1A2, UGT1A9, UGT1A1 and UGT1A3; baicalein acting on the CYP3A4 and UGT1A6 respectively.     

Cytochrome P450 1 enzyme inhibition and anticancer potential of chromene amides from Amyris plumieri

Cytochrome P450 (CYP) enzyme inhibitory properties of six chromenylated amide compounds (CAs) from Amyris plumieri are described. Inhibition of CYP microsomes (CYP1A1, CYP1A2, CYP1B1, CYP2D6, CYP3A4 and CYP2C19) was monitored using a fluorescent assay. Potent inhibition was found against CYP1A1 with IC₅₀ and K_i for CA1 (acetamide), being the lowest at 1.547 ± 1.0 μM and 0.37 μM respectively, displaying non-competitive kinetics. The selectivity for CYP1A1 was increased in CA3 (butanamide), which also exhibited cytotoxicity against breast cancer cells, MCF7 with an IC₅₀ of 47.46 ± 1.62 μM. Structure-activity relationship studies provide insight at a molecular level for CAs with implications in chemoprevention and chemotherapy.     

Anti-HBV activities of Streblus asper and constituents of its roots

The extracts from leaves, heartwood, barks and roots of the Streblus asper were investigated for anti-HBV activities, separately. The results suggested that the MeOH extracts of the heartwood, barks, and roots exhibited good anti-HBV activities. Further investigations displayed that ethyl acetate and n-butanol soluble parts of their MeOH extracts showed more significant anti-HBV activities. Moreover, a new lignan, together with 11 known compounds, was isolated from n-butanol-soluble part of MeOH extract of the roots of S. asper. The structures were elucidated by spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC) and HR-EI-MS experiments. Compounds 1-3 were evaluated for their anti-HBV activities. Honokiol showed significant anti-HBV activity with IC(50) values of 3.14μM and 4.74μM for HBsAg and HBeAg with no cytotoxicity respectively, while lamivudine (3TC, positive control) exhibited weak anti-HBV activity with IC(50) values of 11.81μM and 25.80μM for HBsAg and HBeAg respectively.     

HPLC-based activity profiling of Angelica pubescens roots for new positive GABAA receptor modulators in Xenopus oocytes

A petroleum ether extract of the traditional Chinese herbal drug Duhuo (roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan), showed significant activity in a functional two-microelectrode voltage clamp assay with Xenopus oocytes which expressed recombinant γ-aminobutyric acid type A (GABA_A) receptors of the subtype α₁β₂γ_2S. HPLC-based activity profiling of the active extract revealed six compounds responsible for the GABA_A receptor modulating activity. They were identified by microprobe NMR and high resolution mass spectrometry as columbianetin acetate (1), imperatorin (3), cnidilin (4), osthol (5), and columbianedin (6). In concentration-dependent experiments, osthol and cnidilin showed the highest potentiation of the GABA induced chloride current (273.6% ± 39.4% and 204.5% ± 33.2%, respectively at 300 μM). Bisabolangelone (2) only showed minor activity at the GABA_A receptor. The example demonstrates that HPLC-based activity profiling is a simple and efficient method to rapidly identify GABA_A receptor modulators in a bioactive plant extract.     

Flavonoids with antiplasmodial and cytotoxic activities of Macaranga triloba

A new flavanone derivative, malaysianone A (1), four prenylated flavanones, 6-prenyl-3'-methoxyeriodictyol (2), nymphaeol B (3), nymphaeol C (4) and 6-farnesyl-3',4',5,7-tetrahydroxyflavanone (5), and two coumarins, 5,7-dihydroxycoumarin (6) and scopoletin (7), were isolated from the dichloromethane extract of the inflorescences of Macaranga triloba. The structures of these compounds were elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D), UV, IR and mass spectrometry. The cytotoxic activity of the compounds was tested against several cell lines, with 5 inhibiting very strongly the growth of HeLa and HL-60 cells (IC(50): 1.3 μg/ml and 3.3 μg/ml, respectively). Compound 5 also showed strong antiplasmodial activity (IC(50): 0.06 μM).     

In vivo antidepressant activity of sesquiterpenes from the roots of Valeriana fauriei Briq

Antidepressant activity-guided fractionation of the MeOH extract of Valeriana fauriei Briq. roots resulted in the isolation of two new germacrane-type sesquiterpenes (1-2) in addition to seven known ones (3-9). Their structures were elucidated as 1β,10α-dihydroxyl-8α-acetoxyl-10β,11,11-trimethyl-4-formyl-bicyclogermacren-E-4(5)-ene (1), 1β-hydroxyl-8α-acetoxyl-11,11-dimethyl-4-formyl-bicyclogermacren-E-4(5),10(14)-diene (2), bicyclo[8,1,0]5β-hydroxyl-7β-1acetoxyl-5α,11,11'-trimethyl -E-1(10)-ene-4α,15-olide (3), 8α-acetoxyl-3α,4α,10-trihydroxyl-guaia-1(2)-ene-12,6α-olide (4), 2-Ethylhexyl-4-hydroxybenzoate (5), 11αH-gemacra-1(10)E,4Z-diene-3-one-12,6α-olide (6), β-Sitoterol (7), isovaleric acid (8), isoborneol acetate (9), using a combination of UV, IR, mass spectroscopy, 1D and 2D NMR spectroscopy. The antidepressant activity of compounds 1-4 was investigated by the FST on mice. Among them, compounds 3 and 4 showed the significant antidepressant activity (*, P<0.01).     

Solanum incanum and S. heteracanthum as sources of biologically active steroid glycosides: confirmation of their synonymy

A new spirostanol saponin (1), along with four known saponins, dioscin (2), protodioscin (3), methyl-protodioscin (4), and indioside D (5), and one known steroid glycoalkaloid solamargine (6) were isolated from the two synonymous species, Solanum incanum and S. heteracanthum. The structure of the new saponin was established as (23S,25R)-spirost-5-en-3β,23-diol 3-O-{β-D-xylopyranosyl-(1→2)-O-α-L-rhamnopyranosyl-(1→4)-[O-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside}, by using a combination of 1D and 2D NMR techniques including (1)H, (13)C, COSY, TOCSY, NOESY, HSQC and HMBC experiments and by mass spectrometry. The compounds 1, 3, 4 and 5 were evaluated for cytotoxicity against five cancer cell lines and for antioxidant and cytoprotective activity.     

Bioactive polar compounds from stem bark of Magnolia officinalis

Two new phenylethanoid glycosides magnoloside D (1) and E (2), together with nine known compounds, were isolated from the polar part of methanol extract of the stem bark of Magnolia officinalis. The structures of the new compounds were established on the basis of spectral analysis. Anti-spasmodic activity of four major constituents (3, 4, 9 and 11) was tested in isolated colon of rat, compounds 3, 4, and 9 showed inhibition against acetylcholine, with the effect similar to that of magnolol and honokiol. At the same time, antioxidant activity of the isolated compounds was investigated using a DPPH and an ORAC assay. All of the compounds, except compound 8 showed potent antioxidant capacity in the ORAC assay, while compounds 1-5 and 11 exhibited potent antioxidant activity in the DPPH assay.     

Bioactivity guided isolation of antipsychotic constituents from the leaves of Rauwolfia tetraphylla L

This study was undertaken to ascertain the antipsychotic properties of Rauwolfia tetraphylla L. leaves and to isolate and characterize the antipsychotic constituents. Among the MeOH extract and some alkaloidal fractions at different pHs, the alkaloidal CHCl(3) fraction at pH-9 (2C) showed the highest antipsychotic activity against dopaminergic (DA-D(2)) and serotonergic (5-HT(2A)) receptors in-vitro and amphetamine induced hyperactive mouse model in-vivo. The activity guided isolation of CHCl(3) fraction (2C) afforded six indole alkaloids: 10-methoxytetrahydroalstonine (1), isoreserpiline (2), an isomeric mixture of 11-demethoxyreserpiline (3) and 10-demethoxyreserpiline (4), α-yohimbine (5) and reserpiline (6). Given orally, alkaloids 3-6 showed significant antipsychotic activity in a dose dependent manner. None of the extract, alkaloidal fractions or alkaloids showed any extra pyramidal symptoms at the tested doses. It was also observed that MeOH extract was behaving similar to other clinically used novel atypical antipsychotics in having 5-HT(2A) occupancy greater than the DA-D(2) receptor at the tested doses. Further toxicity and safety evaluation studies of MeOH extracts of R. tetraphylla leaves at different doses (10, 100, 300 and 2000 mg/kg) on female Swiss albino mice showed that MeOH extract is non toxic. The isolated alkaloids, 3-6 could serve as a promising lead structure for drug development of treating psychotic conditions in human.     

Anti-androgenic effect of sesquiterpenes isolated from the rhizomes of Curcuma aeruginosa Roxb

Six sesquiterpenes: germacrone (1), zederone (2), dehydrocurdione (3), curcumenol (4), zedoarondiol (5) and isocurcumenol (6) were isolated from rhizomes of Curcuma aeruginosa Roxb. (Zingiberaceae). They inhibited 5α-reductase which converts testosterone to dihydrotestosterone (DHT). Germacrone (1) was the most potent (IC(50)=0.42±0.05 mg/mL). Compound 1 was anti-androgenic in LNCaP cells when proliferation was testosterone-induced. The growth of flank gland of male Syrian hamsters is dependent on circulating androgen and when maintained with testosterone, 1 (3, 30, 100μg) inhibited growth but was ineffective against DHT. The similar activity profile was observed on the 5α-reductase inhibitor, finasteride (100 μg) treatment group. The androgen receptor binding assay showed that 1 did not bind to the androgen receptor. In conclusion, 1 showed anti-androgenic effect on in vitro and in vivo assays. One of the possible mechanisms was inhibition 5α-reductase activity. Thus, 1 is a potential lead compound for treatment of androgen-dependent disorders.     

Ent-trachyloban-19-oic acid isolated from Iostephane heterophylla as a promising antibacterial agent against Streptococcus mutans biofilms

From the roots of Iostephane heterophylla, six known compounds, namely, ent-trachyloban-19-oic acid (1), the mixture of ent-kaur-16-en-19-oic acid (2) and ent-beyer-15-en-19-oic acid (3), xanthorrhizol (4), 16α-hydroxy-ent-kaurane (5) and 16α-hydroxy-ent-kaur-11-en-19-oic acid (6) were isolated using a bioassay-guided fractionation method. The known compounds (1-6) were identified by comparison of their spectroscopic data with reported values in the literature. In an attempt to increase the resultant antimicrobial activity of 1 and 4, a series of reactions was performed on ent-trachyloban-19-oic acid (1) and xanthorrhizol (4), to obtain derivatives 1a, 1b, and 4a-4d. All the isolated compounds (1-6) and the derivatives 1a, 1b, and 4a-4d were evaluated for their antimicrobial activity against two oral pathogens, Streptococcus mutans and Porphyromonas gingivalis associated with caries and periodontal disease, respectively. Compounds 1, 1b, 2+3, 4 and 4d inhibited the growth of S. mutans with concentrations ranging from 4.1 μg/mL to 70.5 μg/mL. No significant activity was found on P. gingivalis except for 4 with an MIC of 6.8 μg/mL. The ability of 1, 1b, 2+3, 4 and 4d to inhibit biofilm formation by S. mutans was evaluated. It was found that 1, 1b, 4 and 4d interfered with the establishment of S. mutans biofilms, inhibiting their development at 32.5, 125.0, 14.1 and 24.4 μg/mL, respectively.     

Cytotoxic triterpene saponins from the leaves of Aralia elata

Phytochemical investigation of the leaves of Aralia elata has led to the isolation of four new compounds, 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl oleanolic acid (1), 3-O-[β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)]-[β-D-glucopyranosyl (1→2)]-β-d-glucopyranosyl hederagenin 28-O-β-D-glucopyranoside (2), 3-O-{[β-D-glucopyranosyl (1→2)]-[β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl (1→3)]-β-D-glucopyranosyl} oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-[β-D-glucopyranosyl (1→2)]-[β-D-glucopyranosyl (1→3)]-β-d-glucopyranosyl caulophyllogenin (4) and two known compounds, 3-O-[β-D-glucopyranosyl (1→3)-α-l-arabinopyranosyl]-echinocystic acid (5) and 3-O-α-L-arabinopyranosyl echinocystic acid (6). The structural determination was accomplished with spectroscopic analysis, in particular (13)C-NMR, 2D-NMR and HR-ESI-MS techniques. Compounds 1-6 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. Compound 1 showed significant cytotoxic activity against HL60 and A549 cancer cells with IC(50) values of 6.99μM and 7.93μM respectively. In addition, compounds 5 and 6 showed significant cytotoxic activity against HL60 cancer cells with IC(50) values of 5.75μM and 7.51μM, respectively.     

Phenolics from Bidens bipinnata and their amylase inhibitory properties

A new chlorinated flavonoid, 3, 6, 8-trichloro-5, 7, 3', 4'-tetrahydroxyflavone (1), a new biscoumaric acid derivative, 4-O-(2″, 3″-O-diacetyl-6″-O-p-coumaroyl-β-d-glucopyranosyl)-p-coumaric acid (2), and 8, 3', 4'-trihydroxyflavone-7-O-β-d-glucopyranoside (3) together with twenty-four known compounds (4-27) were isolated from the whole plant of Bidens bipinnata. All chemical structures were established on the basis of UV-, MS- and NMR ((1)H, (13)C, (1)H-(1)H COSY, HMQC and HMBC) spectroscopic data. Some of the isolated compounds were tested for the inhibition of α-amylase. The result showed that isookanin (6) was a potent inhibitor of α-amylase (IC(50)=0.447mg/ml).     

Steroidal saponins from Fritillaria pallidiflora Schrenk

Five new steroidal saponins, Pallidifloside D (1), Pallidifloside E (2), Pallidifloside G (5), Pallidifloside H (6) and Pallidifloside I (7), together with seven other steroidal saponins (3, 4, 8-12) were isolated from the dry bulbs of Fritillaria pallidiflora Schrenk. Their structures were established by spectroscopic techniques (IR, MS, 1D and 2D NMR) and chemical means. The isolated steroidal saponins were evaluated for cyotoxic activity against human C6 brain gliomas and Hela cervix cancer cell lines using MTT assays. Compounds 1, 10, 11, 12 showed cytotoxicity against C6 and Hela cell lines with IC(50) values in the range of 5.1-75.8μM.     

Two new nortriterpenoid saponins from Salicornia bigelovii Torr. and their cytotoxic activity

Investigation of characteristic constituents of Salicornia bigelovii Torr. led to isolation of two new 30-nortriterpenoid glycosides, Bigelovii A (1), Bigelovii B (2), together with two known 30-nortriterpenoid glycosides 3-4 and three known oleanane-type triterpenoid glycosides 5-7. The structures of new compounds were elucidated by extensive 1D and 2D NMR, and MS spectroscopic analysis, and chemical evidences. All compounds were isolated for the first time from Chenopodiaceae. Thus compounds 1-4 were evaluated for their cytotoxicity and compouds 1, 3 showed moderate activity against four cell lines, HL-60 (promyelocytic leukemia), MCF-7 (breast carcinoma), HepG2 (liver carcinoma) and A549 (lung carcinoma), with IC(50) values of 6.18, 78.08, 13.64 and >100μM for 1; 31.87, >100, ~100, >100μM for 3, respectively.     

Anti-neuroinflammatory constituents from Polygala tricornis Gagnep

Two new compounds (S)-(+)-butyl-4-methylene-5-oxo-pyrrolidin-2-carboxylate (1) and (5-formylfuran-2-yl)methyl 4-hydroxy-2-methylenebutanoate (2), together with four known compounds (3-6) were isolated from the roots of Polygala tricornis Gagnep. Their structures were determined on the basis of 1D- and 2D-NMR experiments and by comparison with physical data of known compounds. All the isolated compounds were examined for their inhibitory effect on the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in BV-2 microglial cells, and compounds 1 and 2 exhibited pronounced inhibition on the NO production with IC(50) values of 14.1 μM and 1.77 μM, respectively.     

Reactive oxygen species scavenging activities and inhibition on DNA oxidative damage of dimeric compounds from the oxidation of (−)-epigallocatechin-3-O-gallate

The dimeric catechins dehydrotheasinensin A (2) and theacitrin C (3) were prepared from the oxidation of (−)-epigallocatechin-3-O-gallate (EGCG, 1), and their antioxidant activity was investigated using a chemiluminescence (CL) method in vitro. Both compounds showed significant inhibitory effects on reactive oxygen species (O₂⁻, H₂O₂ and •OH) and DNA oxidative damage, with 2 being more potent than 3 and EGCG itself.     

Sesquiterpenes from the marine red alga Laurencia composita

Four new chamigrane derivatives, laurecomin A (1), laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5), and three known halogenated structures, deoxyprepacifenol (6), 1-bromoselin-4(14),11-diene (7), and 9-bromoselin-4(14),11-diene (8), were isolated from the marine red alga Laurencia composita collected from Pingtan Island, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 2 was active against both brine shrimp and fungus Colletotrichum lagenarium.     

Heptaketides with antiviral activity from three endolichenic fungal strains Nigrospora sp., Alternaria sp. and Phialophora sp

Two new heptaketides, (+)-(2S,3S,4aS)-altenuene (1a) and (-)-(2S,3S,4aR)-isoaltenuene (2a), together with six known compounds, (-)-(2R,3R,4aR)-altenuene (1b), (+)-(2R,3R,4aS)-isoaltenuene (2b), 5'-methoxy-6-methyl-biphenyl-3,4,3'-triol (3), alternariol (4), alternariol-9-methyl ether (5), and 4-hydroxyalternariol-9-methyl ether (6) were isolated from the EtOAc extract of an endolichenic fungal strain Nigrospora sphaerica (No.83-1-1-2). Compounds 1a and 1b were separated from enantiomers 1 by chiral HPLC, and so were 2a and 2b from enantiomers 2. Interestingly, 1-6 were also obtained from other two endolichenic fungal strains Alternaria alternata (No.58-8-4-1) and Phialophora sp. (No.96-1-8-1). The structures of 1-6 were elucidated by means of MS, HR-MS, NMR, and X-ray diffraction. Furthermore, the absolute configurations of 1a-2b were determined by CD experiments and CD calculation. Of these compounds, 4 and 5 showed antiviral activity against herpes simplex virus (HSV) in vitro, with IC(50) values of 13.5 and 21.3 μM, and with selective index (SI) values of 26.5 and 17.1, respectively.     

Toxicarioside M, a new cytotoxic 10β-hydroxy-19-nor-cardenolide from Antiaris toxicaria

A new 10β-hydroxy-19-nor-cardenolide, named toxicarioside M (1), was isolated from the trunk bark of Antiaris toxicaria (Pers.) Lesch (Moraceae), along with six known cardenolides (convallatoxin (2), convallatoxol (3), convalloside (4), 3-O-ß-D-xylopyranosylstrophanthidin (5), glucostrophanthidin (6) and strophanthidin (7)). Their structures were elucidated on the basis of HR-MSⁿ analysis, spectroscopic methods (IR, UV, 1D and 2D NMR) and by comparison with data reported in the literature. The cardenolides were evaluated for their cytotoxic activity against KB, HCT-116, SF-268, MCF-7, HL-60, PC-3 and MRC-5 cell lines.