[Study on the chemical constituents of Viscum ovalifolium]

OBJECTIVE

To study the chemical constituents of Viscum ovalifolium.

METHODS

The chemical constituents from Viscum ovalifolium were isolated and purified by silica gel column chromatography, polyamide column chromatography and recrystallization methods. Their structures were elucidated by physicochemical properties and spectral analysis.

RESULTS

Twelve compounds were isolated and their structures were identified as 1-octadecene (1), ethyl palmitate (2), 28-hydrxy-amyrone (3), betulinic acid (4), rutin (5), quercetin (6), beta-amyrinpalmitate (7), lupeol acetate (8), beta-amyrin (9), beta-sitosterol (10), lupeol (11) and oleanolic acid (12).

CONCLUSION

Compounds 1 - 6 are obtained from this plant for the first time.

[Screening and identifying of hepatoprotective compounds in paeoniae radix rubra]

OBJECTIVE

To establish a new rapid method to screen potential hepatoprotective compounds from traditional Chinese medicine, and identify the hepatoprotective compounds in Paeoniae Radix Rubra.

METHOD

Fluorescein diacetate labelled and MTT assay were applied for screening the hepatoprotective fractions on HepG2 cells exposed to galactosamine. The active fractions were analyzed by chromatography coupled with mass spectrometry. Finally, the hepatoprotective effects of the identified compounds were validated by hepatoprotective assay.

RESULT

Three hepatoprotective fractions were founded, in which three compounds were identified as paeoniflorin, ethyl palmitate and ethyl linoleate. Validation results indicated that all the three compounds can attenuate the galactosamine induced injury on HepG2 cells.

CONCLUSION

Paeoniflorin, ethyl palmitate and ethyl linoleate from paeoniae radix rubra showed potential hepatoprotective activity.

Fast ultrasound-assisted extraction of polar (phenols) and nonpolar (lipids) fractions in Heterotheca inuloides Cass

INTRODUCTION

Heterotheca inuloides Cass., also known as "arnica", is used in traditional medicine in Mexico.

OBJECTIVE

Development of fast methods for the extraction of lipidic and phenolic fractions from arnica plants and their subsequent characterization.

METHODOLOGY

Ultrasound was applied to accelerate extraction of the target compounds from this plant and reduce the use of organic solvents as compared with conventional methods. Gas chromatography-ion trap mass spectrometry and liquid chromatography with diode-array detection were used for the characterization of the lipidic and phenolic fractions, respectively.

RESULTS

Under optimal extraction conditions, 9 and 55 min were necessary to complete extraction of the lipidic and phenolic fractions, respectively. The fatty acids present at the highest concentrations in H. inuloides were eicosatetraenoic n3 (24.6 μg/g), cis-9-hexadecenoic n7 (23.1 μg/g), exacosanoic (22.7 μg/g) and cis-9-octadecenoic acid (21.3 μg/g), while the rest were in the range 7.6-1.3 μg/g. The most concentrated phenols were guaiacol (41.5 μg/g), catechin (38.7 μg/g), ellagic acid (35.9 μg/g), carbolic acid (24.2 μg/g) and p-coumaric acid (19.5 μg/g), while the rest were in the range 5.1-0.4 μg/g.

CONCLUSION

Ultrasound reduces the time necessary to complete the extraction 160 and 26 times, the extraction volume 2.5 and 4 times, and increases the extraction efficiency 5 and 3 times for lipidic and phenolic fractions, respectively, in comparison with conventional extraction methods. In addition, the characterization of the lipidic and phenolic fractions constitutes a first approach to the H. inuloides metabolome.

Derivatives of 10,16-dihydroxyhexadecanoic acid isolated from tomato (Solanum lycopersicum) as potential material for aliphatic polyesters

The main monomer of tomato cuticle, 10,16-dihydroxyhexadecanoic acid (or 10,16-dihydroxypalmitic acid; 10,16-DHPA), was isolated and used to efficiently synthesize two different monomers (16-hydroxy-10-oxo-hexadecanoic and 7-oxohexa-decanedioic acids) in addition to a dimer and linear and branched trimers. These compounds were fully characterized using NMR and MS techniques and could be used as starting materials for the synthesis of a wide range of chemicals and bio-polyesters, particularly the latter due to their physical properties, non-toxicity, and relative abundance among raw materials.

Clytostoma callistegioides (Bignoniaceae) wax extract with activity on aphid settling

A bioassay-guided fractionation of leaf extracts from Clytostoma callistegioides (Cham.) Bureau ex Griseb. (Bignoniaceae) led to isolation of a natural mixture of four fatty acids with anti-insect activity against aphids. The compounds were identified by GC-MS as palmitic, stearic, linoleic and linolenic acids and quantified as their methyl esters. The anti-aphid activity of the natural mixture was traced to linolenic and linoleic acids, as shown by the settling inhibition activity of synthetic samples. Interestingly, the saturated acids (palmitic and stearic) tested alone stimulated settling on one of the tested aphids (Myzus persicae), but not on the other tested species (Rhopalosiphum padi). Although ubiquitous, none of these free acids have been previously reported in this Bignoniaceae species. The leaf surface chemistry, which is likely involved in modulating aphid settling behavior, was further investigated for the occurrence of lipophilic substances by histochemical staining. Short, stalked glandular trichomes, previously undescribed for this species, stained with osmium tetroxide and Sudan III, suggesting that the secretion of the defensive acids is related to these surface trichomes.

Chemical constituents from the roots of Homonoia riparia

A new compound and twelve known compounds were isolated from the ethyl acetate extract of the roots of Homonoia riparia Lour, which are used in folk medicine for treatment of hepatitis, bellyache and scald, by the method of silica gel column chromatography repeatedly with a gradient of PE-EtOAc, PE-Me2CO, CHCl3-Me2CO, CHCl3-MeOH. Their structures were identified as a new compound 1-oxo-aleuritolic acid (1), and twelve known compounds aleuritolic acid (2), 3-acetoxy-aleuritolic acid (3), taraxerone (4), taraxerol (5), methyl 3-acetoxy-12-oleanen-28-oate (6), 3-acetoxy-12-oleanen-28-ol (7), ursolic acid (8), lupenol (9), 3beta-acetoxy-lupenol (10), cleomiscosin A (11), chrysophanol (12), and gallic acid (13), which were obtained from this plant for the first time, by the spectroscopic techniques of NMR, HMBC, IR and MS, separately. Among the cytotoxicities evaluation of compounds 1 -3 towards AGZY 83-a (human lung cancer cells) and SMMC-7721 (human liver cancer cells) tumor cells was assayed by MTT methods with cis-dichlorodiamminoplatinum (DDP) used as positive control. Compound 2 exerted weak activity against AGZY 83-a with the IC50 value of 33.055 microg x mL(-1), while 1 and 3 showed no activity to these two cell lines.

Antifilarial activity in vitro of polycarpol and 3-O-acetyl aleuritolic acid from cameroonian medicinal plants against Onchocerca gutturosa

Previous results have revealed the antifilarial activities of crude extracts and pure compounds from some Cameroonian medicinal plants against Onchocerca volvulus and Onchocerca gutturosa. In our efforts to find new filaricidal agents against adult male O. gutturosa worms, we have isolated and screened three compounds: polycarpol and polyveoline from Polyalthia suaveolens (Annonaceae) and 3-O-acetyl aleuritolic acid from Discoglypremna caloneura (Euphorbiaceae). Only polycarpol and 3-O-acetyl aleuritolic acid exhibited significant inhibitory activities on the vitality of adult male worms of O. gutturosa using Amocarzine as positive control compound. The motility reduction values were 28.6 and 57.1%, and the inhibition of MTT reduction values 80.0 and 64.8% respectively.

[Analysis of constituents of essential oil from the skin of water caltrop]

OBJECTIVE

To analyze the constituents of essential oil from the skin of water caltrop.

METHOD

Water steam distillation and GC-MS were used.

RESULT

58 componds were separated respectively. 56 componds being identified which were 96. 5% of the totle essential oil.

CONCLUSION

Diethyl phthalate, acetamide, N-acetyl-N, N'-1,2-ethanediylbis-, isopropyl palmitate, hexadecanoic acid, Z-11 and octadecanoic acid are the main component of essential oil from the skin of water caltrop.

[Preparation of contraceptive pill microcapsule and its anti-fertility effect]

The main component of this pill is 2-Octadecanoic acid-4-Palmitic acid-2, 4-Pentanediyl ester separated from chloroform extract of neem oil. The microcapsules coated by the re-curdle method were fabricated with an average particle size of 100-180 microm. The morphological characteristics, incorporation efficiency, carrier reclamation efficiency of the microcapsule were investigated. Kunming mice were used in the experiment, and the anti-fertility effect of the microcapsule on the histology and apoptosis was studied by light and electron microscopy and the flow cytometry. The data obtained clearly indicated that the microcapsule could lead to the payload of medicine, the incorporation efficiency being 90%. After the microcapsules were given to the male mice orally, its anti-fertility effect came into being and could keep the mice in a state of reversible infertility for a long time. The results of histological study and flow cytometry indicate that the mechanism of its anti-fertility effect involves mainly the inhibition of sperm motility and the arrest of spermatogenic process.

[Studies on the chemical constituents of the essential oil from the leaves of Dalbergia odorifera T. Chen]

OBJECTIVE

To study the constituents of the essential oil from the leaves of Dalbergia odorifera T. Chen.

METHOD

The constituent were separated and identified by GS-MS.

RESULT

21 compounds from the essential oil were identifed, which account for 77.71% of total volatile oils, 21.73% of 2-methoxy-4-vinylphenol, 13.97% of n-hexadecanoic acid, 6.69% of phenol.

CONCLUSION

The study provided a chemical basis as a medicinal herb.

[Study on optimizing the extraction process of total free organic acids in Pinellia ternate Breit]

OBJECTIVE

To optimize the extraction process of total free organic acids in Pinellia ternate Breit.

METHOD

The optimum extraction was investigated by total free organic acids determined by direct potential titration. The concentration of ethanol, amount of ethanol, extraction time and extraction times were the four factors in the experiment.

RESULTS

The optimum extraction process was adding 10 times amount of 75% ethanol, refluxing for 2 times, 1 h each time.

CONCLUSION

This extraction process shows higher yield of total free organic acids in Pinellia ternate Breit and is available for industrial production.

Synthesis of (R)- and (S)-10,16-dihydroxyhexadecanoic acid: cutin stereochemistry and fungal activation

The first asymmetric syntheses of the cutin monomers (R)- and (S)-10,16-dihydroxyhexadecanoic acid (10,16-DHPA) and confirmation of (S)(+)-absolute configuration for 10,16-DHPA derived from tomato are reported. The individual DHPA stereoisomers display differences in their ability to activate the fungal pathogen Colletotrichum trifolii.

Total synthesis of 2-methoxy-14-methylpentadecanoic acid and the novel 2-methoxy-14-methylhexadecanoic acid identified in the sponge Agelas dispar

The phospholipid FA composition of the Caribbean sponge Agelas dispar was revisited and 40 different FA were identified. Among these a novel 2-methoxylated FA, namely, the anteiso methyl-branched 2-methoxy-14-methylhexadecanoic acid, was identified together with the recently discovered iso methyl-branched 2-methoxy-14-methylpentadecanoic acid and the normal-chain 2-methoxytetradecanoic acid. The structures of the iso and anteiso methyl-branched 2-methoxylated FA were confirmed by total syntheses, which were accomplished in seven steps and in 45-48% overall yields. Other phospholipid FA identified in A. dispar include the unusual methyl-branched 10,13-dimethyltetradecanoic acid, 3,7,11,15-tetramethylhexadecanoic (phytanic) acid, and the 11-methyloctadecanoic acid. In addition, the delta5,9 FA (5Z,9Z)-15-methyl-5,9-hexadecadienoic acid and (5Z,9Z)-5,9-octadecadienoic acid were characterized. These findings establish alternative FA biosynthetic possibilities for these marine organisms.

[Isolation and identification of chemical constituents from Acropora pulchra]

Three compounds, N-1-(hydroxymethyl)-2-hydroxyl-(E,E)-3,7-heptadecadienal-hexadecanamide(1), batyl alcohol(2) and n-cetanol(3) were isolated from the EtOAc portion of the ethanol extract of the hard coral Acropora pulchra collected from north China sea, and their structures were determined by MS, 1HNMR, 13CNMR analysis.

Palmitic acid is the major fatty acid responsible for significant anti-N-methyl-N'-nitro-N-nitroguanidine (MNNG) activity in yogurt

We describe here the isolation and identification of palmitic acid as being responsible for significant anti-N-methyl-N'-nitro-N-nitroguanidine (MNNG) activity in yogurt. The Ames test (Salmonella typhimurium TA100) was used to direct fractionation of activity. Yogurt was freeze-dried and extracted with acetone to yield a crude extract. The crude extract was purified by normal phase silica gel, Sephadex LH-20, and reversed phase medium pressure liquid chromatographies. The major compound in the active medium pressure liquid chromatographic fractions was determined to be palmitic acid on GC and high pressure liquid chromatography (HPLC) systems, and by nuclear magnetic resonance (NMR) analysis. Other saturated straight chain and methyl branched fatty acids were detected by GC/MS and were later shown to possess anti-MNNG activity. Of the straight chain fatty acids, palmitic acid had the highest anti-MNNG activity. All omega - 1 methyl branched fatty acids tested were more active than their straight chain counterparts. A trace amount of isopalmitic acid (14-methyl pentadecanoic acid), a minor milk lipid, was detected in one of the active fractions, and was later shown to be five times more active than palmitic acid. Isopalmitic acid also inhibited mutagenesis induced 4-nitroquinoline-N-oxide (4NQO), and 7, 12-dimethyl benz[a]anthracene (DMBA), and was found to inhibit the metabolic activation of DMBA.

[Chemical constituents of Cyclocarya paliurus (Batal.) Iljinsk]

Four compounds were isolated from the leaves of Cyclocarya paliurus. They were identified as daucosstero, beta-L-arabopyranose, steraric acid and palmitic acid on the basis of spectral data and chemical properties. All of them were isolated from this plant for the first time.

Confirmation by gas chromatography/mass spectrometry of two unusual trans-3-monoethylenic fatty acids from the Nova Scotian seaweeds Palmaria palmata and Chondrus crispus

The structures of two unusual fatty acids, the known trans-3-hexadecenoic acid and a novel trans-3-tetradecenoic acid, both isolated from the Nova Scotian seaweeds Palmaria palmata and Chondrus crispus, were positively identified. After the extraction of the total fatty acids by saponification, followed by methylation, the monoenoic trans fractions were isolated by thin-layer chromatography on silica gel impregnated with silver nitrate. The monoenoic trans fractions were derivatized with 2-amino-2-methyl-propanol prior to analysis by gas chromatography/mass spectrometry. The mass spectra showed prominent [M + 1]+ ions but lacked the 12 amu interval useful for identifying the double bond position. Hence, alternative diagnostic peaks were used to confirm the position of the double bond in these two fatty acids. As the trans-3-hexadecenoic acid is found in the photosynthetic tissue of all plants, it may also be present in ruminant fats and, presumably, in human adipose tissue.

Calibration of albumin-fatty acid binding constants measured by heptane-water partition

Most measurements of binding affinity of albumin for long-chain fatty acids are based on heptane-water partition. In this method, equilibrium partition of fatty acid between heptane and an albumin-containing buffer is calibrated using the partition ratio between heptane and buffer in the absence of protein. In the current study, we used a variety of techniques to examine potential problems with this approach. Hydrophobic impurities in commercial [3H]palmitate preparations were incompletely removed by standard purification techniques. These impurities contributed from 5% of the total radioactivity in the heptane phase at low albumin concentrations (5 microM) to 62% at higher albumin concentrations (500 microM), thus confounding determination of binding affinity. These were identified by gas chromatography/mass spectroscopy as radio-labeled glycerol monopalmitate and monostearate. When albumin was not present, the partition ratio was similar to values reported by others. However, our results varied by a factor of four (265-1,119) depending on how the solutions were prepared. Although a true equilibrium partition must not depend on starting conditions, the partition ratio after 24-72 h was > 2x as large when tracer [3H]palmitate was added to the heptane phase than when it was added to the aqueous phase. Results also depended on the relative volumes of heptane and buffer used, approaching a maximum of 1,445 +/- 112 for very low heptane/buffer volume ratios. Much of this variability was due to hydrophilic impurities in [3H]palmitate, which ranged from 0.2 to 1.2% in commercial lots down to 0.1-0.5% after alkaline ethanol extraction and < 0.05% after thin-layer chromatography (TLC).(ABSTRACT TRUNCATED AT 250 WORDS)

[Chemical constituents of Emilia sonchifolia L. DC]

Five known compounds were obtained from the whole plant of Emilia sonchifolia. By means of chemical and spectral methods, they were identified to be simiral, beta-sitosterol, stigmasterol, palmitic acid and honey acid.

[Constituents of the dry roots of Rehmannia glutinosa Libosch]

From the extract of dry roots of Rehmannia glutimosa, fatty acids, palmitic acid, beta-sitosterol, daucosterol and sulfur (Ss) cyclic compound were isolated and identified. The latter four were isolated for the first time.

Chemical communication of emigration behavior of Drosophila melanogaster. II. Identification of chemical substances

Two chemical substances isolated from adult flies of Drosophila melanogaster differently affected the emigration activity of genetically different strains. These substances were identified as palmitic acid and oleic acid, respectively. Chemical and biological comparisons of the natural and authentic compounds showed them to be identical. The behavior response was dependent on the concentration of these fatty acids. The two chemical substances are excreted by adult flies, both male and female, but the emigration activity of one strain was affected by only palmitic acid and that of the other strain, by only oleic acid.

Podoscyphic acid, a new inhibitor of avian myeloblastosis virus and Moloney murine leukemia virus reverse transcriptase from a Podoscypha species

A novel enzyme inhibitor of RNA-directed DNA-polymerases of avian myeloblastosis and murine leukemia virus was isolated from fermentations of an tasmanian Podoscypha species. Its structure was elucidated by spectroscopic methods and oxidative degradation as (E)-4,5-dioxo-2-hexadecenoic acid (1). The enzyme inhibitor, which was named podoscyphic acid, did not inhibit DNA and RNA synthesis in permeabilized L 1210 cells nor did it affect RNA synthesis in isolated nuclei of L 1210 cells. 1 inhibits protein synthesis in whole L 1210 cells and rabbit reticulocyte lysate and shows very weak antimicrobial and cytotoxic properties. The testing of ethyl (E)-4,5-dioxo-2-hexadecenoate (2) and (E)-4-oxo-2-tetradecenoic acid (11) revealed the importance of the free gamma-oxoacrylic acid unit for the biological activities of 1.

[Chemical constituents of the pericarp of Trichosanthes rosthornii Harms]

Nine compounds were isolated from the pericarp of T. rosthornii and identified on the basis of spectral data to be palmitic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, L-(-)-alpha-monopalmitin, delta 7-stigmastenol, delta 7-stigmastenone-3 and delta 7-stigmatenol-3-beta-D-glucopyranoside. All but the last one are obtained from this species for the first time.

Interaction of fatty acid binding protein with microsomes: removal of palmitic acid and retinyl esters

[14C] palmitic acid or [3H] retinyl esters incorporated in microsomal membranes were removed by a cytosolic fraction enriched in fatty acid binding protein. When mouse liver cytosol was fractionated by 70% ammonium sulphate, a precipitate and a soluble fraction were obtained. The soluble fraction containing the fatty acid binding protein was able to remove from microsomal membranes, [14C] palmitic acid or [3H] retinyl esters, whereas the precipitate fraction had no removal capacity. Retinoid analysis indicated that 70% ammonium sulphate soluble fraction was enriched in endogenous retinyl esters with regard to cytosol or 70% ammonium sulphate precipitate fraction.

Identification of the new 18-hexacosenoic acid in the sponge Thalysias juniperina

The phospholipid fatty acids from the sponge Spheciospongia cuspidifera were studied revealing the presence of the rare 10-octadecenoic acid (10-18:1) and a new 2-methoxyhexadecenoic acid. The phospholipid fatty acids from Thalysias juniperina were also studied revealing the presence of the hitherto unreported 18-hexacosenoic acid (18-26:1). These results tend to indicate that the biosynthetic pathway from 10-18:1 to 18-26:1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by 31P-NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.

[Volatile components of herbal Cynomorii]

The volatile components were obtained from Herba Cynomorii for the first time (yield 0.02%). These components were analysed by TLC and GC-MS. Twenty-two compounds, including the main components hexadecanoic acid and 9-octadecenoic acid, were identified. Their percent contents were given.

Precipitation of calcium palmitate from bile salt-containing dispersions

Addition of calcium chloride to mixed micellar systems composed of sodium salts of palmitic acid and high concentrations of different bile acids results in precipitation of Ca(palmitate)2 only when the palmitate concentration exceeds a critical value, which is dependent on the concentrations of Ca2+, Na+ and bile salt, and on the type of bile salt used. All these dependencies, as well as the complex and interrelated effects of the various parameters on the kinetics of Ca(palmitate)2 precipitation are consistent with the following mechanism: (i) calcium binds to palmitate-bile salt mixed micelles and promotes their aggregation, at a rate governed by the concentration ratio between bound calcium and micelles (here denoted "binding ratio"). (ii) Ca(palmitate)2 precipitation occurs within the aggregate of micelles only if those micelles include sufficient amounts of Ca2+ and palmitate to allow for the formation of large enough crystal units of Ca(palmitate)2 which can serve as nucleation "seeds". Both the concentrations of micelles and Na+ have dual effects on the rate of precipitation. Increasing micelle concentration, by itself, accelerates aggregation but at the same time leads to a decrease of the binding ratio, thus reducing the rate of precipitation. Na+ which reduces the binding ratio through competitive binding also reduces the surface charge, thus assisting micelle aggregation. Our model also explains the facilitation of precipitation observed when phosphatidylcholine is contained in the palmitate-bile salt mixed micelles and the inhibitory effect of the water soluble bovine serum albumin.

Occurrence of galactosylceramide in pig epidermal cells

Monoglycosylceramides were isolated from pig epidermal cells which had been prepared free from dermal elements. The most polar glycolipid among the five isolated monoglycosylceramides was galactosylceramide. The galactosylceramide was composed of alpha-hydroxypalmitic acid and 16- and 18-carbon chain sphingenine, being quite different from epidermal glucosylceramides. This is the first report demonstrating the occurrence of galactosylceramide in mammalian epidermal cells.

Displacement chromatography of oligomycins

Oligomycins A, B and C were separated by reversed-phase chromatography in the displacement mode on octadecylsilica columns. The carrier was a mixture of methanol and water and a saturated solution of palmitic acid in the carrier served as the displacer. The production rate was investigated as a function of the chromatographic conditions, i.e., methanol concentration in the carrier, displacer concentration, flow-rate and the amount and concentration of the oligomycin mixture in the feed solution. A practical guide for method development is given.

A rapid assay for activity of phospholipase A2 using radioactive substrate

A rapid method for the assay of phospholipase A2 has been developed using a radioactive substrate, L-alpha-dipalmitoyl-(2-[9,10(N)-3H]palmitoyl)-phosphatidylcholine. The substrate diluted with cold carrier (1 mM) is dissolved in 80% ethanol containing 25 mM sodium deoxycholate. The enzymatic reaction is performed in 1.0 ml 0.1 M glycine-NaOH buffer, pH 9.0, containing 2 mumol CaCl2, 10 micrograms bovine serum albumin, 2.5 mumol sodium deoxycholate, 0.01 unit (or less) phospholipase A2, and 40-100 nmol substrate. The enzymatic reaction is terminated by adding 0.2 ml 5% Triton X-100 solution containing 40 mumol EDTA. The product of the enzymatic reaction, radioactive palmitic acid, is extracted by 10 ml hexane containing 0.1% acetic acid in the presence of anhydrous sodium sulfate (0.5 g/ml). Activity of phospholipase A2 is directly determined from the radioactivity in the hexane extract. The present method achieves a quick separation of the radioactive product, [3H]palmitic acid, from the radioactive substrate, L-alpha-dipalmitoyl-(2-[3H]palmitoyl)-phosphatidylcholine, without the need of separation by TLC.

High-performance liquid chromatography of fatty acid isopropylidene hydrazides and its application in lipid analysis

Fatty acid isopropylidene hydrazides, prepared by stepwise treatment of acyl lipids with hydrazine and acetone, were analyzed by high-performance liquid chromatography on a reversed-phase column. These derivatives could be easily eluted with 15% water in methanol and monitored by measuring absorbance at 229 nm with a uv detector. Their elution behavior, in general, was similar to that of methyl esters and some commonly used ultraviolet-absorbing derivatives of fatty acids. The new method has been used for fatty acid analysis of some oils.

Antineoplastic agents. 51. The yellow jacket Vespula pensylvanica

An ethyl alcohol extract of the yellow jacket Vespula pensylvanica Saussure was found to inhibit growth of the murine P388 lymphocytic leukemia cell line. Separation of a ligroin fraction guided by bioassay led to characterization of the cytotoxic constituents as oleic acid (1a) and palmitoleic acid (1b). Evidence was also found for the presence of palmitic acid and the sterols sitosterol, campesterol and cholesterol.

Quantitative recovery of free and esterified fatty acids from thin-layer plates coated with silica gel

A method is described for the recovery of fatty acids from silica gel on thin-layer plates. The method is simple and rapid and depends on the conversion of silica gel to potassium silicate, using potassium hydroxide, followed by acidification in such a way that the silicic acid is kept in solution. Fatty acids are then extracted by shaking with solvent. Fatty acid recovery from free fatty acid, phospholipid, glyceride and cholesterol ester zones is more than 90% efficient. There is no oxidation or isomerization of unsaturated fatty acids.