Method Validation and Evaluation of Safrole Persistence in Cowpea Beans Using Headspace Solid-Phase Microextraction and Gas Chromatography.

Bioinsecticides are regarded as important alternatives for controlling agricultural pests. However, few studies have determined the persistence of these compounds in stored grains. This study aimed at optimizing and validating a fast and effective method for extraction and quantification of residues of safrole (the main component of Piper hispidinervum essential oil) in cowpea beans. It also sought to assess the persistence of this substance in the grains treated by contact and fumigation. The proposed method used headspace solid-phase microextraction (HS-SPME) and gas chromatography with a flame ionization detector (GC/FID). Factors such as temperature, extraction time and type of fiber were assessed to maximize the performance of the extraction technique. The performance of the method was appraised via the parameters selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. The LOD and LOQ of safrole were 0.0057 and 0.019 µg kg-1, respectively and the determination coefficient (R2) was >0.99. The relative recovery ranged from 99.26 to 104.85, with a coefficient of variation <15%. The validated method was applied to assess the persistence of safrole residue in grains, where concentrations ranged from 1.095 to 0.052 µg kg-1 (contact) and from 2.16 to 0.12 µg kg -1 (fumigation). The levels measured up from the fifth day represented less than 1% of the initial concentration, proving that safrole have low persistence in cowpea beans, thus being safe for bioinsecticide use. Thus, this work is relevant not only for the extraction method developed, but also for the possible use of a natural insecticide in pest management in stored grains.

Rapid Method for The Gas Chromatographic Quantitative Analysis to Determinate Safrole in Commercial Essential Oils.

Safrole is a well-known carcinogenic agent that is present in camphor trees. In this study, a gas chromatographic method was established to quantitate the levels of safrole in essential oils using n-decyl alcohol as an internal standard. The method used a nonpolar column and was able to detect concentrations of safrole as low as 5 µg/ml in the samples. Following addition of 2-10 mg of safrole into 1 g of essential oil extracted from Stout Camphor wood (Cinnamomum kanehirai Hayata) or 1-10 mg of safrole into 1 g of essential oil extracted from Small-flower Camphor wood (Cinnamomum micranthum Hayat), the recovery rates of safrole were determined. With direct injection of samples into the gas chromatograph, the results showed that the recovery was more than 96.1%, with a coefficient of variation below 5.6%. We then analyzed 23 commercially available Stout Camphor and other essential oil samples and found that 21 of them contained safrole in the range of 37.65-355.07 mg/g. In addition, in the heavier essential oil distilled from Small-flower Camphor wood, the safrole level was up to 642.98 mg/g. Our results demonstrated that most camphor essential oils on the market have a carcinogenic potential due to their high safrole levels.

Anti-hepatoma effect of safrole from Cinnamomum longepaniculatum leaf essential oil in vitro.

The aim of this study was to study the anti-hepatoma effect of safrole and elucidate its molecular mechanism, the human hepatoma BEL-7402 cells were incubated with various concentrations (40, 80, 160, 320 and 640 µg/ml) of safrole and the cell proliferation and apoptosis were evaluated. The results showed that both the cell proliferation determined by 3-(4,5-dimethyl-thiazolyl-2)-2,5-diphenyl tetrazolium brominde (MTT) assay and cell colony determined by soft agar assay were significantly suppressed by safrole in a dose-time-dependent manner. Characteristic morphological and biochemical changes associated with apoptosis, including cells shrinkage, deformation and vacuolization of mitochondria, nuclear chromatin condensation and fragmentation, formation of apoptotic bodies were observed when treated with safrole for 24 h and 48 h. Cell cycle changes evaluated by flow cytometry analysis showed that the safrole could induce accumulation of cells arrested at G1 and S phases of the cell cycle. These results demonstrated that safrole is potent anti-hepatoma agent and the underlying mechanism may be attributed to suppress tumor cell growth by inducing cell apoptosis.

Apratoxin H and apratoxin A sulfoxide from the Red Sea cyanobacterium Moorea producens.

Cultivation of the marine cyanobacterium Moorea producens, collected from the Nabq Mangroves in the Gulf of Aqaba (Red Sea), led to the isolation of new apratoxin analogues apratoxin H (1) and apratoxin A sulfoxide (2), together with the known apratoxins A-C, lyngbyabellin B, and hectochlorin. The absolute configuration of these new potent cytotoxins was determined by chemical degradation, MS, NMR, and CD spectroscopy. Apratoxin H (1) contains pipecolic acid in place of the proline residue present in apratoxin A, expanding the known suite of naturally occurring analogues that display amino acid substitutions within the final module of the apratoxin biosynthetic pathway. The oxidation site of apratoxin A sulfoxide (2) was deduced from MS fragmentation patterns and IR data, and 2 could not be generated experimentally by oxidation of apratoxin A. The cytotoxicity of 1 and 2 to human NCI-H460 lung cancer cells (IC50 = 3.4 and 89.9 nM, respectively) provides further insight into the structure-activity relationships in the apratoxin series. Phylogenetic analysis of the apratoxin-producing cyanobacterial strains belonging to the genus Moorea, coupled with the recently annotated apratoxin biosynthetic pathway, supports the notion that apratoxin production and structural diversity may be specific to their geographical niche.

[New neolignan from seed of Myristica fragrans].

OBJECTIVE: To study the chemical constituents in the nutmeg (seed of Myristica fragrans). METHOD: The chemical constituents were isolated by various column chromatographic methods and structurally elucidated by IR, NMR and MS evidences. RESULT: Fifteen compounds were obtained and identified as myristicin (1), methyleugenol (2), safrole (3), 2, 3-dihydro-7-methoxy-2(3, 4-methylenedioxyphenyl)-3-methyl-5-(E) -propenyl-benzofuran (4), dehydrodiisoeugenol (5), 2, 3-dihydro-7-methoxy-2-(3-methoxy-4, 5-methylenedioxyphenyl) -3-methyl-5-(E)-propenyl-benzofuran (6), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3, 4-dimetho- xyphenyl) propane (7), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3, 4, 5-trimethoxyphenyl) propane (8), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3, 4-dimethoxyphenyl) propan-1-ol acetate (9), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3, 4-dimethoxyphenyl) propan-1-ol (10), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3, 4, 5-trimethoxyphenyl) propan-1-ol (11), 5-methoxy-dehydrodiisoeugenol (12), erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)-propan-1-ol (13), guaiacin (14) and threo-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(3-methoxy-5-hydroxy-phenyl) propan-1-ol (15). CONCLUSION: Compound 15 is a new compound and named myrisisolignan. Compound 7 is isolated from the genus Myristica for the first time.

[GC-MS analysis of essential oil from nutmeg processed by different traditional methods].

OBJECTIVE: To analyze the chemical components of the essential oil extracted from the seeds of Myristica fragrans (nutmeg) processed by different methods (steamed with water steam, roasted with flour, sauted with flour, roasted with talcum powder, roasted with loess, and roasted with bran) and to provide quality control foundations in the sciences. METHOD: The essential oil was extracted by steam distillation and separated with GC capillary column. The relative content of every compound was determined with area normalization method and the structures were elucidated by GC-MS technique. RESULT: Fifty-eight to one hundred and four of chromatographic peaks were detected, among them seventy-six compounds accounting for 98.32% to 99.99% of the total essential oil in nutmeg were identified, which were composed of 69.15% to 97.24% for monoterpenoids and 2.06% to 25.51% for aromatic compounds of the total essential oil, respectively. CONCLUSION: It was shown that monoterpenoids and their derivatives were main composition, and aromatic compounds were secondary composition in the total essential oil of nutmeg grows in Indonesia and processed by different traditional methods on the basis of theory of traditional Chinese medicine. In addition, it was suggested that we should be careful to use processed nutmeg owing to contain safrole and a-asarone induced genetoxicity in animals and mutagenicity in the Ames Salmonella assay, and myristicin and elemicin induced narcotism in human. The processed method roasted with bran for nutmeg may be better and will be developed.

Theory and use of the pseudophase model in gas-liquid chromatographic enantiomeric separations.

The theory and use of the "three-phase" model in enantioselective gas-liquid chromatography utilizing a methylated cyclodextrin/polysiloxane stationary phase is presented for the first time. Equations are derived that account for all three partition equilibria in the system, including partitioning between the gas mobile phase and both stationary-phase components and the analyte equilibrium between the polysiloxane and cyclodextrin pseudophase. The separation of the retention contributions from the achiral and chiral parts of the stationary phase can be easily accomplished. Also, it allows the direct examination of the two contributions to enantioselctivity, i.e., that which occurs completely in the liquid stationary phase versus the direct transfer of the chiral analyte in the gas phase to the dissolved chiral selector. Six compounds were studied to verify the model: 1-phenylethanol, alpha-ionone, 3-methyl-1-indanone, o-(chloromethyl)phenyl sulfoxide, o-(bromomethyl)phenyl sulfoxide, and ethyl p-tolylsulfonate. Generally, the cyclodextrin component of the stationary phase contributes to retention more than the bulk liquid polysiloxane. This may be an important requirement for effective GC chiral stationary phases. In addition, the roles of enthalpy and entropy toward enantiorecognition by this stationary phase were examined. While enantiomeric differences in both enthalpy and entropy provide chiral discrimination, the contribution of entropy appears to be more significant in this regard. The three-phase model may be applied to any gas-liquid chromatography stationary phase involving a pseudophase.

A traditional method of Cinnamomum carolinense preparation eliminates safrole from a therapeutic Pohnpean tea.

Cinnamomum carolinense, locally known as madeu, is a tree endemic to the volcanic mountains of the Island of Pohnpei in the Eastern Carolines of the South Pacific. The bark is harvested from trees and brewed to make a medicinal tea and hot beverage that is regularly consumed. Many species of Cinnamomum contain the known hepatocarcinogen safrole, sparking concern regarding habitual consumption of this beverage. HPLC-PDA analysis confirmed the presence of the carcinogen in alcoholic extracts of Cinnamomum carolinense bark shavings (0.435%, w/w), but safrole was not detected in the tea. The limit of detection and limit of quantitation of safrole were determined to be 1.25 and 3.75 microg/mL, respectively. The traditional preparation method, which boils the bark shavings, degrades the safrole.

Microbiologic oxidation of isosafrole into piperonal.

The biotransformation of isosafrole by Cladosporium sphaerospermum yielded piperonal, which is a compound of great commercial importance in the flavor and fragrance industries. The experiments were performed in 500-mL conical flasks containing 100 mL of Czapek-modified medium in an orbital shaker with controlled agitation and temperature. Spores of C. sphaerospermum were used as inocula, and after 96 h of incubation the substrate was added to the culture. Samples of 2 mL were withdrawn at 24-h intervals and analyzed by gas chromatography, (GC) and/or GC/MS spectroscopy.

Oxygen-containing sulfur-rich compounds from the bark of the tropical garlic tree Scorodophloeus zenkeri Harms.

Two sulphoxides (2,3,5-trithiahexane 5-oxide and 2,4,5,7-tetrathiaoctane 2-oxide), three novel sulphones [S-(methylthiomethyl)methanesulfonothioate, methylthio(methylthio-methyl)sulfone, 2,3,5,7-tetrathiaoctane3,3-dioxide] and four known sulphones [methylsulphonylmethylthiomethane, methylmethanethiosulfonate, bis-methyl-sulphonylmethane, and bis-(methylthiomethyl)sulfone] were isolated from the bark extracts of Scorodophloeus zenkeri Harms. The structures were determined by spectral methods, essentially MS and NMR experiments.

Separation ability and stoichiometry of cyclodextrin complexes.

Gas-liquid chromatography has been applied to search relations between selectivity towards isomers and stoichiometry of cyclodextrin complexes. The model tested compounds were: dimethylnaphthalenes and alpha- and beta-pinenes as constitutional isomers; cis/trans decalins, anetholes and isosafroles as diastereomers and as enantiomers (+/-)-alpha-pinenes and (+/-)-camphenes. Experimental retention data are used to confirm a simple theoretical model that allows distinguishing formation of G x CD complexes (1:1) and G x CD2 complexes (1:2). Based on the experimental data, stability constants K were evaluated. It has been found that remarkable selectivity factor alpha may appear both within the range of 1:1 stoichiometry (beta-CD complexes of decalins and of alpha- and beta-pinenes) and 1:2 stoichiometry (alpha-CD complexes with (+/-)-alpha-pinenes and (+/-)-camphenes). Occasionally selectivity arises from a different composition, when one isomer forms a 1:1 stoichiometry complex while another forms a 1:2 complex (dimethylnaphthalenes, cis/trans-anetholes and cis/trans-isosafroles).

[GS-MS analysis of essential oils from five species of Asarum].

This paper reports the result of GS-MS analysis of the essential oils from five species of Asarum, namely, A. heterotropoides var. mandshuricum (cultivated), A. sieboldii (cultivated), A. caudigerellum (from Sichuan), A. sieboldii(from Shandong) and A. sieboldii(wild). Ninety-two constituents were detected, of which 73 compounds were identified.

[GC-MS analysis of essential oils from the pericarps of Illicium majus Hook.f.et. Thoms. and I. micranthum Dunn].

The chemical constituents of essential oils from the pericarps of Illicium majus and I. micranthum were analyzed. Seventy-two compounds have been identified by GC-MS, of which safrole, linalool and limonene are higher in content.