Tran Dinh Thang

Composition of essential oils of four Hedychium

BackgroundVietnam is a country blessed with many medicinal plants widely used as food and for medicinal purposes, and they contain a host of active substances that contribute to health. However, the analysis of chemical constituents of these plant species has not been subject of literature discussion.ResultsIn this study, the chemical compositions of essential oils of four Hedychium species, obtained by hydrodistillation, were determined by means of gas chromatography-flame ionization detector (GC-FID) and gas chromatography–mass spectrometry (GC-MS) techniques. Individually, α-pinene (52.5%) and β-pinene (31.8%) were present in the leaf oil of Hedychium stenopetalum Lodd., while linalool (45.2%), (E)-nerolidol (8.7%) and α-pinene (5.0%) were identified in the root. The leaf of Hedychium coronarium J. König was characterized by α-pinene (20.0%), linalool (15.8%), 1,8-cineole (10.7%), α-pinene (10.1%) and α-terpineol (8.6%); while α-pinene (23.6%), α-humulene (17.1%) and β-caryophyllene (13.0%) were identified in the root. Hedychium flavum Roxb., gave oil whose major compounds were α-pinene (22.5%), α-humulene (15.7%) and β-caryophyllene (10.4%) in the leaf; α-humulene (18.9%), β-caryophyllene (11.8%) and α-pinene (11.2%) in the stem, as well as α-pinene (21.8%), linalool (17.5%) and 1,8-cineole (13.5%) in the root. The main constituents of Hedychium ellipticum Buch.-Ham. ex Smith were (E)-nerolidol (15.9%), α-pinene (11.8%) and bornyl acetate (9.2%) in the leaf with 1,8-cineole (40.8%), α-pinene (18.3%) and α-pinene (11.0%) occurring in the root.ConclusionsUbiquitous monoterpenes and sesquiterpenes were identified as characteristic markers for Hedychium species. This work is of great importance for the evaluation of Hedychium essential oils grown in Vietnam.

Anti-inflammatory Diterpenoids from Croton tonkinensis

Phytochemical investigation of the methanolic extract of Croton tonkinensis afforded two known kauranes (1, 2), eight new ent-kauranes (3-10), and 16 known ent-kaurane-type diterpenoids (12-27). In addition, 30 known compounds were identified by comparison of their physical and spectroscopic data with reported data. Among the isolated compounds, ent-18-acetoxykaur-16-en-15-one (20) displayed the most significant inhibition of superoxide anion generation and elastase release.

Constituents of the Roots of Clausena lansium and Their Potential Anti-inflammatory Activity

Eight new carbazole alkaloids, claulamines C (1), D (2), and E (5) and clausenalines B-F (3, 4, 6-8), four new coumarins, clausemarins A-D (9-12), and 43 known compounds were isolated from the roots of Clausena lansium. The structures of the new compounds were established on the basis of 2D-NMR spectroscopic analysis, and their absolute configurations were established from their ECD spectra. The configuration of wampetin was revised as E using a NOESY experiment. Most of the isolated compounds were evaluated for their potential anti-inflammatory activity. The results showed that compounds 9, 13-18, and 20-22 exhibited strong inhibition of superoxide anion generation with IC50 values ranging from 1.9 to 8.4 μM, while compounds 18, 19, and 21 inhibited elastase release with IC50 values in the range from 2.0 to 6.9 μM.

Bioactive constituents of Clausena lansium and a method for discrimination of aldose enantiomers

Glycosides, clausenosides A and B, and carbazole alkaloids, clausenaline A, claulamine A, and claulamine B, together with 50 known compounds, were isolated from the stems of Clausena lansium. Their structures were determined by means of spectroscopic methods, including that of CD and 1D/2D NMR analysis. Claulamine A has a 1-oxygenated carbazole skeleton with a rare 2,3-lactone ring, and claulamine B represents an hitherto unknown acetal carbazole alkaloid. Thirty-one of the isolated known compounds were evaluated in various assays for anti-inflammatory activity. Among them, imperatorin, isoheraclenin, and osthol exhibited selective and potent inhibition of formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation, and lansiumarin C also decreased nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-induced macrophages. In addition, a modified HPLC method of pre-column derivatization was developed that is more practical for simultaneous analysis of aldose enantiomers as compared to the literature method. The absolute configurations of the sugar moieties in clausenosides A and B were determined with this modified method.

Chemical constituents from Abutilon indicum

The investigation on the chemical constituents of the whole plant of Abutilon indicum has resulted in the isolation of two new compounds, abutilin A (1) and (R)-N-(1′-methoxycarbonyl-2′-phenylethyl)-4-hydroxybenzamide (2), as well as 28 known compounds. The structures of the two new compounds were established on the basis of the spectroscopic analysis, and the known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature.

Study on the volatile oil contents of Annona glabra L., Annona squamosa L., Annona muricata L. and Annona reticulata L., from Vietnam.

The volatile compounds identified from four species of Annona from Vietnam are being reported. The oils were obtained from aliquots of plant samples by steam distillation and subjected to GC and GC–MS analysis. The main compounds of Annona glabra L., were β-caryophyllene (21.5%) germacrene D (17.7%), α-cadinol (5.4%) and β-elemene (5.2%). Annona squamosa L., comprised mainly of α-pinene (1.0–11.9%), limonene (0.8–11.7%), β-cubebene (0.5–13.0%), β-caryophyllene (11.6–24.5%), spathulenol (0.8–9.0%), caryophyllene oxide (1.0–10.6%) and α-cadinol (3.3–7.8%). The significant constituents of Annona muricata L., were α-pinene (9.4%), β-pinene (20.6%), ρ-mentha-2,4(8)-diene (9.8%), β-elemene (9.1%) and germacrene D (18.1%). However, camphene (0.2–6.6%), α-copaene (2.0–7.3%), β-elemene (5.9–16.6%), β-caryophyllene (8.3–14.9%), β-bisabolene (0.4–10.2%), δ-cadinene (1.7–4.8%) and germacrene D (9.3–22.8%) were the main compounds common to samples of Annona reticulata L. There were significant amounts of sabinene (11.2% and 2.7%; leaf and stem bark) and bicycloelemene (9.6% and 6.1%; stem and bark).

Chemical compositions of the leaf essential oils of some Annonaceae from Vietnam

The leaf oils of some genus of Annonaceae collected from Vietnam in December 2009 were analyzed by capillary gas chromatography (GC) and GC coupled with mass spectrometry (GC/MS). The major compounds identified in the oil of Artabotrys pallens Ast. were α-gurjunene (21.9%), α-phellandrene (20.1%) and bicycloelemene (9.6%). The oil of Goniothalamus tamirensis Pierre ex Finet & Gagnep. contained β-selinene (12.3%), bicyclogermacrene (10.9%), caryophyllene oxide (10.4%) and bicycloelemene (5.6%) in abundance. However, β-pinene (33.4%), α-pinene (32.3%) and β-caryophyllene (10.5%) were the most quantitative significant constituents of Dasymaschalon rostratum Merr. & Chun. From the oil of Uvaria pierrei Finet & Gagnep. we could identified bicycloelemene (18.3%), germacrene D (30.2%), bicyclogermacrene (26.4%) and β-bisabolene (7.7%) as the major compounds, while γ-elemene (54.0%) was the most singly abundant constituent of Uvaria dac Pierre ex Finet & Gagnep oil. All the other compounds were identified in amount less than 5% with the most prominent ones being myrcene (3.8%) and limonene (3.8%). In addition, the oil of Melodorum vietnamensis Ban., had an abundance of α-pinene (15.4%), bicyclogermacrene (13.9%), bicycloelemene (10.8%) and β-caryophyllene (9.9%). The chemotaxonomic importance of the results was also discussed.

Chemical composition of the essential oil of Ocimum Basilicum cultivated in Mongolian Desert-Gobi

Ocimum Basilicum L. (Sweet Basil ) is cultivated commercially in many countries (e.g., India, France, Marocco, Italy) mainly for its essential oil, which is used extensively in the pharmaceutical and cosmetics industries. The medicinal propertie s of the plant are highlighted by its use as a carminative and stimulant. The seeds are said to have demulcent and diuretic properties [1, 2] and the oil’s pleasant odor is responsible for its use in expensive perfumes, liqueurs, and expensive seasonings [3]. They are also commonly cultivated in many other tropical countries, such as South America, Madagascar, Sri Lanka, Cambodia, Malaysia, Indonesia, the Philippines, etc. [4]. Ocimum Basilicum L. is an introduced species to Fiji and is recognized as a useful therapeutic agent among these peoples [1, 5]. The aromatic leaves are used fresh or dried as a flavoring agent for food and confectionery products and posses antimicrobial activity [6]. A number of different chemotypes of Sweet Basil exist. Varieties rich in methyl cinnamate, linalool, 1.8-cineole, methyl chavicol, and eugenol have been established [7, 8]. Seeds of Ocimum Basilicum L. from the USA were used in this study. The air-dried parts of Ocimum Basilicum were hydrodistilled in a Clevenger-type apparatus [9] for 2 h. About 15 mg of oil, which was dried with anhydrous sodium sulfate, was dissolved in 1 mL of CH 3OH (for spectroscopy or for chromatography). GC analysis was performed on an HP 6890 Plus gas chromatograph equipped with a FID and fitted with an HP-5 column (L = 25 m, ID = 0.25 mm). The analytical conditions were: carrier gas H 2, injector temperature (PTV) 250°C, detector temperature 260°C, temperature programmed 60° (2 min hold) to 220° (10 min hold) at 4°C/min. The Hewlett–Packard 6890 Plus chromatograph was fitted with the fused silica capillary column HP-5. The conditions of use were the same as described above with He as carrier gas, interface with the mass spectrometer HP 5972 MSD (70 eV). The temperature was programmed as reported a bove. Component identific ation was carried out by comparing MS data with those reported in the Wiley library on Chemstation HP, and in some cases with substances identified from the oil’s known composition and also with standard substances [10]. Oxygenated constituents are the most important compounds: 1.8-cineol (8.54%), linalool (27.26%), methylchavicol (19.77%), and ( Z)-α-bergamotene (10.00%) (Table 1).

Bioactive 6S-styryllactone constituents of Polyalthia parviflora.

Parvistones A-E (1-5), five new styryllactones possessing a rare α,β-lactone moiety and a 6S configuration, were isolated from a methanolic extract of Polyalthia parviflora leaves. The structures and the absolute configuration of the isolates were elucidated using NMR spectroscopy, specific rotation, circular dichroism, and X-ray single-crystal analysis. Compounds 8, 9, 11, and 12 were isolated for the first time. The results were supported by comparing the data measured to those of 6R-styryllactones. Moreover, a plausible biogenetic pathway of the isolated compounds was proposed. The structure-activity relationship of the compounds in an in vitro anti-inflammatory assay revealed the 6S-styryllactones to be more potent than the 6R derivatives. However, the effect was opposite regarding their cytotoxic activity. In addition, 6S-styrylpyrones isolated showed more potent anti-inflammatory and cytotoxic activity when compared to the 1S-phenylpyranopyrones obtained.

Chemical constituents from the leaves of Annona reticulata and their inhibitory effects on NO production.

In the present study, the chemical investigation of the leaves of Annona reticulata has resulted in the identification of nine compounds, including annonaretin A, (1), a new triterpenoid. The purified compounds were subjected to the examination of their effects on NO inhibition in LPS-activated mouse peritoneal macrophages and most of them exhibited significant NO inhibition, with IC50 values in the range of 48.6 ± 1.2 and 99.8 ± 0.4 μM.