Chemical investigation of <i>Phyllanthus reticulatus</i> by HPLC‐SPE‐NMR and conventional methods

Lam, Sio Hong; Wang, Chen Yu; Chen, Chien Kuang; Lee, Shoei‐Sheng

doi:10.1002/pca.979

Cited by 32 publications

(16 citation statements)

References 12 publications

(10 reference statements)

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“…Hence, the HPLC-NMR technique has been applied to study the metabolic profile of some drugs (Burton et al, 1997;Spraul et al, 2003). The HPLC-SPE-NMR technique has also been successfully applied in analysis of natural products (Wang and Lee, 2005;Lam et al, 2007;Lee et al, 2007) as well as in identification of certain metabolites (Godejohann et al, 2004;Sandvoss et al, 2005). In the present study, HPLC-SPE-NMR, along with HPLC-HRESIMS, was applied to the characterization of the dicentrine metabolites in the urine of miniature pigs.…”

Section: Introductionmentioning

confidence: 99%

Metabolism of Dicentrine: Identification of the Phase I and Phase II Metabolites in Miniature Pig Urine

Lai¹,

Kuo²,

Chen³

et al. 2010

Drug Metab Dispos

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ABSTRACT:The metabolic profile of dicentrine, a selective ␣ 1 -adrenoceptor antagonist with potent antiarrhythmic and antihypertensive activities, in miniature pig urine via oral administration was investigated for the first time. The urine, collected after a single oral administration of dicentrine, was pretreated using solvent extraction and column chromatographic methods to identify the metabolites containing fractions. Twenty-four metabolites (MI-1-9 and MII-1-15), of which 21 compounds are new, were identified by mass spectrometry and high-performance liquid chromatography-diode array detector solid-phase extraction-NMR techniques. Of these, 14 metabolites (MI-5, MII-1 and 2, and MII-5-15) were further isolated for structure confirmation. The phase I metabolic transformations of dicentrine were found to be N-demethylation, N-oxidation, O-demethylation (9,10-OMe), O,O-demethylenation (1-OCH 2 O-2), and hydroxylation at the benzylic (C-4) and the aromatic (C-3) positions, whereas those for the phase II were O-glucuronidation and O-glucosylation of the phenolic group of the phase I metabolites.

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Section: Introductionmentioning

confidence: 99%

Metabolism of Dicentrine: Identification of the Phase I and Phase II Metabolites in Miniature Pig Urine

Lai¹,

Kuo²,

Chen³

et al. 2010

Drug Metab Dispos

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“…Prominent among these is the technique of HPLC-SPE-NMR, for which a SPE cartridge is used to trap multiple injections of a metabolite to enable sufficient accumulation for NMR measurement and thereby eliminating the eluent effect on 1 H NMR signals. Various studies successfully applied such a technique to identify the metabolites of drugs or bioactive compounds (Burton et al, 1997;Spraul et al, 2003;Godejohann et al, 2004;Sandvoss et al, 2005;Lai et al, 2010) and the constituents in complex natural products (Wang and Lee, 2005;Lam et al, 2007;Lee et al, 2007). In the present study, HPLC-SPE-TT-NMR, which equipped a liquid handler between SPE and NMR to transfer compound from SPE to a 2-mm NMR tube for NMR measurement, and HPLC-HRESIMS were applied to characterize the metabolites of (2S)-pterosin A (1) in rat urine, collected in 24 h after intragastrical oral administration (Brant and Remon, 1991).…”

Section: Introductionmentioning

confidence: 99%

Metabolism of (2S)-Pterosin A: Identification of the Phase I and Phase II Metabolites in Rat Urine

Lee¹,

Hsu²,

Kang³

et al. 2012

Drug Metab Dispos

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ABSTRACT:The metabolic profile of the potent hypoglycemic agent, (2S)-pterosin A (1), in rat urine via intragastrical oral administration was investigated. In total, 19 metabolites (M1-M19) were identified. Among these, 16 metabolites were characterized by high-performance liquid chromatography solid-phase extraction-tube transfer-NMR, and seven metabolites were further isolated from the treated urine to enable further structural determination. Twelve of these are new compounds. The phase I metabolites of 1 were formed via various oxidations at positions C-3, C-10, C-12, C-13, or C-1 followed by decarboxylation of C-10 or C-14, and lactonization at C-12/C-14 or C-14/C-12. The phase II metabolites were glucuronide conjugates from the parent compound or phase I metabolites. The major metabolites were found to be (2S)-14-O-glucuronylpterosin A (M9), (2S)-2-hydroxymethylpterosin E (M14), and (؎)-pterosin B (M19). Quantitative HPLC analysis of metabolites, based on similar UV absorption and use of the regression equation of 1, indicated that ϳ71% 1 was excreted as metabolites in rat urine.

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“…It also is claimed to have anti-diabetic activity in tribal areas (Kumar et al , 2008). Phyllanthus species have been found to contain bioactive alkaloids, flavonoids, lignan, phenol and terpenes (Lam et al , 2007). Some reports have demonstrated its anti-plasmodial activity (Omulokoli et al , 1997) and antidiabetic activity (Kumar et al , 2008).…”

Section: Resultsmentioning

confidence: 99%

An evaluation of the RNase H inhibitory effects of Vietnamese medicinal plant extracts and natural compounds

Tài

Nhut²,

Nhiệm³

et al. 2011

Pharmaceutical Biology

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In research on anti-human immunodeficiency virus (HIV) agents from natural sources, thirty two extracts of Vietnamese plants and twenty five isolated compounds were screened for their inhibitory effect against the ribonuclease H (RNase H) activity of HIV-1 reverse transcriptase and the cytopathic effect of the HIV virus. At a concentration of 50 μg/mL, eleven plant extracts and five isolated compounds inhibited over 90 percent of RNase H enzymatic activity. Of these, the methanol extracts from the leaves of Phyllanthus reticulatus and Aglaia aphanamixis highly inhibited RNase H activity by 99% and 98%, respectively. Several fucoidans isolated from seaweeds Sargassum kuetzingii, Sargassum polycystum, and Gelidiella acerosa, as well as epigallocatechin-3-gallate isolated from Camellia chinensis also showed strong inhibitory effects over ninety percent. Sixteen plant extracts with inhibition of over seventy five percent in the RNase H assay were tested in a cellular model of HIV-1 cytopathicity; four extracts showed modest activity in protecting against the cytopathic effect of the HIV virus.

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Chemical investigation of Phyllanthus reticulatus by HPLC‐SPE‐NMR and conventional methods

Cited by 32 publications

References 12 publications

Metabolism of Dicentrine: Identification of the Phase I and Phase II Metabolites in Miniature Pig Urine

Metabolism of Dicentrine: Identification of the Phase I and Phase II Metabolites in Miniature Pig Urine

Metabolism of (2S)-Pterosin A: Identification of the Phase I and Phase II Metabolites in Rat Urine

An evaluation of the RNase H inhibitory effects of Vietnamese medicinal plant extracts and natural compounds

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