Isolation, Characterization and Biological Activities of Chemical Constituents of Ophiorrhiza and Hedyotis Species

Chemical investigation on the leaves of Ophiorrhiza species, O. communis and O. tomentosa, has resulted in the isolation of two indole type alkaloids, harman and strictosidinic acid. Strictosidinic acid was isolated from the butanol extract of both Ophiorrhiza communis and O. tomentosa while harman was isolated from O. communis only. The structures of these alkaloids were elucidated using modern spectroscopic techniques such as UV, IR, NMR, MS and also by comparison with the literature. A study on the constituents of Hedyotis verticil lata has resulted in the isolation of kaempferitrin and Hv2 whereas from Hedyotis herbacea, kaempferol-3-0-rutinoside, ursolic acid, kaempferol-3-0-arabinopyranoside and quercetin galactoside were isolated. These structures were determined using modern spectroscopic techniques and also by comparison with the literature. A bioassay was also carried out using brine shrimp and anti bacterial tests on the pure and crude compounds. The brine shrimp tests showed that some of the compounds were very toxic whereas the anti-bacterial tests showed that some compounds have anti-bacterial properties and certainly these compounds have potential for further investigations for their medicinal and practical uses

Chemical Constituents of Hedyotis dichotoma and their Biological Activity

Two compounds, isovitexin and ursolic acid, were isolated from the aerial parts of Hedyotis dichotoma. Anti-microbial assays indicated that isovitexin was active against fungus and candida. The structures of both compounds were assigned using modern spectroscopic techniques

Chemical Constituents of Vitex ovata (Verbenaceae)

Three compounds, luteolin, ursolic acid and meta-hydroxybenzoic acid were isolated from the leaves of Vitex ovata. The structures of the compounds were identified using modern spectroscopic techniques

The Alkaloids of Ophiorrhiza communis and O. tomentosa

Two alkaloids, harman and strictosidinic acid, were isolated from the leaves and bark of Dphiorrhiza communis Linn. Strictosidinic acid was also isolated from Dphiorrhiza tomentosa Jack. These structural assignments were based on their physical and spectroscopic data

6-Benzyl-3-(1,4-dioxaspiro­[4.5]decan-2-yl)-8,8-dimethyl-1-oxa-2,6-diaza­spiro­[4.4]non-2-ene-7,9-dione

In the title compound, C23H28N2O5, the 4,5-dihydro­isoxazole ring adopts a slight envelope conformation and the dioxolane ring is in a twisted conformation. The mol­ecular structure, in the vicinity of the benzyl group, may be influenced by an intra­molecular C—H⋯O hydrogen bond which generates an S(7) ring motif. In the crystal structure, mol­ecules are linked via weak inter­molecular C—H⋯O hydrogen bonds, forming extended chains along the b axis. Further stabilization is provided by weak C—H⋯π inter­actions

(5R)-Ethyl 6-benzyl-8,8-dimethyl-7,9-dioxo-1-oxa-2,6-diaza­spiro­[4.4]non-2-ene-3-carboxyl­ate

In the title compound, C18H20N2O5, the pyrrolidine ring adopts an envelope conformation with the C atom bonded to the methyl groups as the flap. The dihydro­isoxazole ring is essentially planar (r.m.s. deviation = 0.041 Å) and forms a dihedral angle of 65.19 (6)° with the phenyl ring. In the crystal, neighbouring mol­ecules are linked into chains along [110] by inter­molecular C—H⋯O hydrogen bonds and weak C—H⋯π inter­actions involving the phenyl ring

Evaluation of antioxidant and nitric oxide inhibitory activities of selected Malaysian medicinal plants

Methanol extracts of seven Malaysian medicinal plants were screened for antioxidant and nitric oxide inhibitory activities. Antioxidant activity was measured by using FTC, TBA and DPPH free radical scavenging methods and Griess assay was used for the measurement of nitric oxide inhibition in lipopolysaccharide (LPS) and interferon-γ (IFN-γ)-treated RAW 264.7 cells. All the extracts showed strong antioxidant activity comparable to or higher than that of α-tocopherol, BHT and quercetin in FTC and TBA methods. The extracts from Leea indica and Spermacoce articularis showed strong DPPH free radical scavenging activity comparable with quercetin, BHT and Vit C. Spermacoce exilis showed only moderate activity but other species were weak as compared to the standards. In the Griess assay Lasianthus oblongus, Chasalia chartacea, Hedyotis verticillata, Spermacoce articularis and Leea indica showed strong inhibitory activity on nitric oxide production in LPS and IFN-γ-induced RAW 264.7 cells. Extracts from Psychotria rostrata and Spermacoce exilis also inhibited NO production but this was due to their cytotoxic effects upon cells during culture

Effects of the Absorption Behaviour of ZnO Nanoparticles on Cytotoxicity Measurements

ZnO absorbs certain wavelengths of light and this behavior is more pronounced for nanoparticles of ZnO. As many toxicity measurements rely on measuring light transmission in cell lines, it is essential to determine how far this light absorption influences experimental toxicity measurements. The main objective was to study the ZnO absorption and how this influenced the cytotoxicity measurements. The cytotoxicity of differently sized ZnO nanoparticles in normal and cancer cell lines derived from lung tissue (Hs888Lu), neuron-phenotypic cells (SH-SY5Y), neuroblastoma (SH-SY5Y), human histiocytic lymphoma (U937), and lung cancer (A549) was investigated. Our results demonstrate that the presence of ZnO affected the cytotoxicity measurements due to the absorption characteristic of ZnO nanoparticles. The data revealed that the ZnO nanoparticles with an average particle size of around 85.7 nm and 190 nm showed cytotoxicity towards U937, SH-SY5Y, differentiated SH-SY5Y, and Hs888Lu cell lines. No effect on the A549 cells was observed. It was also found that the cytotoxicity of ZnO was particle size, concentration, and time dependent. These studies are the first to quantify the influence of ZnO nanoparticles on cytotoxicity assays. Corrections for absorption effects were carried out which gave an accurate estimation of the concentrations that produce the cytotoxic effects

Isolation and cytotoxicity of triterpenes from the roots of Phyllanthus pulcher Wall. ex Müll. Arg. (Euphorbiaceae).

The dried powdered roots of Phyllanthus pulcher Wall. ex Müll. Arg. (Euphorbiaceae), were sequentially extracted with dichloromethane (DCM), ethyl acetate (EtOAc) and methanol (MeOH). The extracts were tested for cytotoxic activity against three human cancer cell lines: MCF-7 (breast), NCI-H460 (lung) and DU-145 (prostate). The DCM extract exhibited the strongest cytotoxic activity compared with EtOAc and MeOH extracts. Hence from the DCM extract, five pentacyclic triterpenes, 3α-acetoxyl-25-hydroxyolean-12-en-28-oic acid (1), glochidone (2), 12(13)-dehydro-3α-acetoxyolean-28-oic acid (3), lupanyl acetate (4) and glochidonol (5) were isolated and identified by spectroscopic analyses (1H NMR, 13C NMR, FT-IR, UV, DEPT, HMQC, HMBC and HREIMS). This is the first report on the isolation of 4 from a natural source, whereas 1 and 3 have already been isolated from the families Hamamelidaceae and Compositae (Asteraceae), respectively. However this is the first study reporting the presence of 1 and 3 in the Euphorbiaceae family. The isolated tritepenes 1-5 were tested against the three human tumour cell lines as stated above. Only compounds 1 and 5 exhibited cytotoxic activity, 5 being most potent with IC50 values ranging 7.5–13.4 µg/mL (17.1–30.5 µM)