In vitro anti-oxidant potential of new metabolites from Hypericum oblongifolium (Guttiferae)

Phytochemical investigations on Hypericum oblongifolium led to the isolation of a flavone named folicitin (1) and a bicyclic conjugated lactone, folenolide (2) from the ethyl acetate fraction of methanolic extract. Both metabolites were characterised as new compounds based on detailed spectroscopic analyses. In vitro anti-oxidant potential of both the compounds was evaluated by the DPPH radical scavenging assay. Compound 1 exhibited significant antioxidant activity while compound 2 was found inactive.     

A new depsidone derivative from the leaves of Garcinia polyantha

One new depsidone, polyanthadepsidone A (1), together with four known compounds were isolated from the dichloromethane extract of the leaves of Garcinia polyantha. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR and EI mass spectral data. All the isolates exhibited suppressive effect on phagocytosis response upon activation with serum opsonised zymosan in the IC₅₀ range of 4.5–23.80 μM, tested in vitro for oxidative burst studies of whole blood.     

Inophyllin A, a new pyranoxanthone from Calophyllum inophyllum (Guttiferae)

In the authors' continuing search for new natural products, their recent studies on the roots of Calophyllum inophyllum (Guttiferae) have yielded a new prenylated pyranoxanthone, Inophyllin A together with the common triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved through (1)H, (13)C, DEPT, COSY, HSQC and HMBC experiments. The molecular mass was determined using MS techniques. The authors report here the isolation of and structural elucidation for Inophyllin A as well as its toxicity test result. The discovery of this new natural product from the unexploited Malaysian forest will certainly contribute to the search for potential natural larvicides.     

Neoorthosiphonone A; a nitric oxide (NO) inhibitory diterpene with new carbon skeleton from Orthosiphon stamineus

From the aerial part of Orthosiphon stamineus from Hainan island of China, a diterpene named neoorthosiphonone A (1), having a novel carbon framework, has been isolated. Neoorthosiphonone A (1) possessed a unique unprecedented structural feature of eight-membered ring C in its structure, which may be biogenetically derived from its isopimarane precursor, orthosiphonone A, through the insertion of vinyl group into the C₁₃-C₁₄ bond. Neoorthosiphonone A (1) displayed potent inhibitory activity on the nitric oxide production in LPS-activated macrophage-like J774.1 cells with an IC₅₀ value of 7.08 μM, more potent than the positive control l-NMMA.     

Cytotoxic polyprenylated benzoylphloroglucinol derivatives with an unusual adamantyl skeleton from Hypericum sampsonii (Guttiferae)

[formula: see text] The structures of sampsoniones I and J, isolated from the aerial parts of the Chinese medicinal plant Hypericum sampsonii, have been elucidated by detailed spectral analysis. They are complex adamantyl derivatives, and sampsonione I is the first polyprenylated benzoylphloroglucinol derivative with the unique caged tetracyclo[7.3.1.1.0]tetradecane-2,12,14-trione skeleton. Cytotoxic sampsonione I has also been obtained by the biomimetic transformation of sampsonione J.     

Neosappanone A, a xanthine oxidase (XO) inhibitory dimeric methanodibenzoxocinone with a new carbon skeleton from Caesalpinia sappan

A novel dimeric methanodibenzoxocinone, named neosappanone A (1), possessing a unique unprecedented novel carbon framework, has been isolated from the heartwood of Caesalpinia sappan L. of Vietnam, and its structure was elucidated on the basis of spectroscopic analysis. Neosappanone A (1) competitively inhibited xanthine oxidase in a concentration-dependent manner (IC₅₀, 29.7 μM; K_i, 16.3 μM).     

A new bibenzyl derivative from Pleione bulbocodioides

A new bibenzyl derivative 1, named 2-（4＇＇-hydroxybenzy1）-3-（3＇-hydroxyphenethy1）-5-methoxy-cyclohexa-2,5-diene-1,4- dione, and two known stilbenoids （2, 3） were isolated from the tubers of Pleione bulbocodioides （Franch.） Rolfe. Their structures were elucidated by spectroscopic methods.     

Mucigerin, a new coumarin from Calophyllum mucigerum (Guttiferae)

Our recent studies on the stem bark of Calophyllum mucigerum (Guttiferae) have yielded a new coumarin mucigerin, a prenylated xanthone cudraxanthone C and the common steroidal triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved using 1H NMR, 13C NMR, DEPT, COSY, HETCOR and HMBC experiments while MS gave the molecular masses. Cytotoxic assays using CEM-SS cell line (T-lymphoblastic leukemia) on the crude extracts of the stem bark indicated some activity. The crude extracts were also found to be moderately toxic against the larvae of Aedes aegypti. This article reports the isolation and identification of mucigerin as well as bioassay data.     

Determination of Active Components in St. John's Wort (Hypericum Perforatum) by Capillary Electrophoresis with Electrochemical Detection

St. John's Wort (Hypericum perforatum) is a medicinal plant which has been known in traditional medicine as an anti‐inflammatory and healing agent. Nowadays, the alcoholic extract of its aerial parts finds wide application for its antidepressant activity. A capillary electrophoresis method for the identification of its constituents using electrochemical detection was developed. Effects of several important factors were investigated to acquire the optimum conditions. The working electrode was a 300 μm carbon disc electrode at a working potential of +0.90 V (vs. SCE). The analytes can be well separated within 20 min in a 75 cm length fused‐sillica capillary at a separation of 16 kV in 50 mmol L^?1 borate buffer (pH=9.0). The current response was linear over about three orders of magnitude with detection limits (S/N=3) ranging from 0.2 to 0.5 mg L^?1 for all the analytes. The method was successfully used in the analysis of Hypericum perforatum with relatively simple extraction procedures, and the assay results were satisfactory.     

A new benzofuranolignan and a new flavonol derivative from the stem of Morus australis

A new benzofuranolignan austrafuran A （1） and a new flavonol derivative 5,7,2′,4′-tetrahydroxy-3-methoxyflavone （2） were isolated from the stem of Morus australis. Their structures were determined on the basis of spectroscopic evidences.     

Pileamartines A and B: Alkaloids from Pilea aff. martinii with a new carbon skeleton

Two novel alkaloids, with an unprecedented carbon skeleton, pileamartines A (1) and B (2), together with the known alkaloid, julandine (I-a) were isolated from the alkaloidal fraction of Pilea aff. martinii leaves. Their structures were established by spectral data analysis, including MS and 2D NMR. The absolute configurations of 1 and 2 were suggested by comparison of their experimental and calculated electronic circular dichroism spectra. Compound 2 exhibited weak inhibitory activity against the α-glucosidase enzyme with an inhibition of 11% at a concentration of 200?µM. These compounds were not cytotoxic against several cancer cell lines even at a concentration of 150?µM.     

A new lignan derivative from the root of Ilex pubescens

One new compound, ilexlignan A （1）, was isolated from the root of llex pubescens. Its structure was elucidated by the combination of one- and two-dimensional NMR analysis, mass spectrometry, CD spectrum measurement and chemical evidence.     

Przewalskin A: A new C23 terpenoid with a 6/6/7 carbon ring skeleton from Salvia przewalskii maxim

Przewalskin A (1), a novel C23 terpenoid with a 6/6/7 carbon ring skeleton, was isolated from Salvia przewalskii. Its structure was determined by comprehensive 1D NMR, 2D NMR, and MS spectroscopic analysis and subsequently confirmed by a single-crystal X-ray diffraction study of its PDC oxidation derivative (2). Compounds 1 and 2 showed modest anti-HIV-1 activity with EC50 = 41 and 89 microg/mL, respectively.     

Salviskinone A, a diterpene with a new skeleton from Salvia przewalskii

A novel compound, named salviskinone A (1), was isolated from Salvia przewarskii. The compound has a rearranged carbon skeleton with a methyl unit at C-5 from abietane-type diterpene. Its structure and relative stereochemistry were elucidated by detailed spectroscopic analysis, including HREIMS and 2DNMR (COSY, HSQC, HMBC, and NOESY) spectra.     

Codonopiloneolignanin A,a polycyclic neolignan with a new carbon skeleton from the roots of Codonopsis pilosula

A neolignan codonopiloneolignanin A(1) with a novel 2,9:2',9:7,7'-tricyclo-8,'-neolignane skeleton was isolated from an aqueous extract of the Codonopsis pilosula roots. Its structure including the absolute configuration was elucidated by extensive spectroscopic analysis, including 2D NMR and electronic circular dichroism calculation. The proposed biosynthetic pathway of compound 1 is also discussed.     

Achilleol B: a new tricyclic triterpene skeleton from Achillea odorata L

Achilleol B ( ), a new tricyclic triterpene, has been isolated from Achillea odorata L. and its structure established on the basis of its NMR data obtained through n.O.e., short and long-range homo and heteronuclear correlation experiments and other spectroscopic evidence.     

Seconoriridone A: A C16-seco-noriridal derivative with a 5/5/7 tricyclic skeleton from Belamcanda chinensis

Seconoriridone A (1), a novel C₁₆-seco-noriridal with a 5/5/7 tricyclic scaffold, was isolated from the rhizome of Belamcanda chinensis. Its structure and absolute configuration were determined by NMR spectroscopy and quantum chemical calculations. Notably, seconoriridone A featured a 2-butanonyl moiety with oxidative cleavage of the conventionally multisubstituted cyclohexane ring of iridals. Seconoriridone A was a mixture of C-14 epimers in the presence of hemiacetal. The plausible biosynthetic pathway for 1 was deduced.     

Ainsliadimer A, a new sesquiterpene lactone dimer with an unusual carbon skeleton from Ainsliaea macrocephala

A phytochemical investigation of Ainsliaea macrocephala led to the isolation of a new dimeric sesquiterpene lactone, ainsliadimer A (1). The structure of 1 was elucidated by spectroscopic analysis, and confirmed by single crystal X-ray diffraction. Ainsliadimer A represents an unusual carbon skeleton with a cyclopentane system connecting the two monomeric sesquiterpene lactone units. This unique molecule exerted potent inhibitory activity against the production of nitric oxide in RAW264.7 stimulated by LPS.     

A new (propylphenyl)bibenzyl derivative from Dendrobium williamsonii

A new (propylphenyl)bibenzyl derivative, dendrowillol A (1), along with 22 known compounds were isolated from the whole plants of Dendrobium williamsonii. Their structures were elucidated by means of extensive spectroscopic analysis. Cytotoxicity evaluation against five human tumour lines showed that all the compounds tested displayed very weak cytotoxicity when compared with the positive control taxol, but selective inhibitory effects on HL-60 for several compounds tested were observed, with IC₅₀ values ranging from 4.48 to 11.04 μM.