Fractionation Of Petroleum Ether Extract Research Articles

Bioassay Directed Fractionation of Petroleum Ether Extract of Aerial Parts of Ceriops tagal: Isolation of Lupeol as the Nematicidal Agent against Cyst Nematode Heterodera zeae.

Plant parasitic cyst nematode Heterodera zeae is a pest, causing substantial economic losses in agriculture. Organic pesticides, based on plant products have emerged as eco-benign nematicidal agents. Ceriops tagal is a well-known marine medicinal plant which has not been evaluated against any nematode. Petroleum ether extract of the aerial parts of the plant (CTP), exhibited promising activity against infective stage larvae of H. zeae. On subjecting to classical solvent-solvent separation, it afforded petroleum ether soluble (CTP-S), methanol soluble (CTPMS-1, CTPMS-2) and insoluble (CTPM-IN-2) fractions, which exhibited activity against the cyst nematode within 24 h exposure. GC, GC/MS and HR-ESI-MS analyses of CTPMS-1 and CTPMS-2 fractions resulted in the identification of a number of compounds, including pentacyclic triterpenoids, lupeol (1), betunal (2), betulin (3), lupenone (4), betulonaldehyde (5), betulonic acid (7), methyl 3-acetoxy-27-O-(3,4-dihydroxy-E-cinnamoyl)-20(29)-lupen-28-oate (8) and β-amyrin, along with phenylpropanoid esters, fatty acids and their derivatives, benzamide, and indole derivatives. CTPM-IN-2 which mainly contained lupeol (1) exhibited maximum nematicidal activity, with 91 % and 93 % mortality of the larvae of H. zeae, after exposure for 72 h at the concentration of 0.5 % and 1 %, respectively. Its fractionation and purification through column chromatography resulted in the isolation and identification of four lupane-type triterpenoids 1, 3, 4 and betulinic acid (6). One of its most abundant column fractions CC-9-18 (145 mg) which exhibited substantial activity, with 81 % mortality at the lowest concentration of 0.125 % after 48 h of incubation mainly contained lupeol. It seems lupeol, a wide spread bio-privileged triterpenoid is the nematicidal principle of the plant as its authentic sample showed LC50 value of 0.061 after 72 h exposure. It is for the first time that nematicidal activity is reported for any part of C. tagal and that of lupeol against H. zeae. Pentacyclic triterpenoids 1-8 are biosynthetically related. Of the twenty-four compounds isolated or identified in the present investigation only five constituents 1, 3, 6, 7 and palmitic acid have been isolated previously from C. tagal.

Characterization on the ultraclean carbons extracted from direct coal liquefaction residue using petroleum ether

ABSTRACT Direct coal liquefaction residue is a coal waste with high ash and sulfur content, but also rich in valuable organic carbons. In this work, the ultraclean carbons were obtained by solvent extraction using petroleum ether at a mild temperature. The petroleum ether extractable fraction is ash-free with high carbon content, but low nitrogen and sulfur. The petroleum ether extractable fraction is reasonable to be cleaned for fuel use or converted into carbon products. Detailed characterizations on the chemical composition and structural features of petroleum ether extractable fraction were performed to supply fundamental information for additional treatment.

Investigation of antiplasmodial efficacy of lupeol and ursolic acid isolated from Ficus benjamina leaves extract

This study emphasizes on the investigation of antiplasmodial activity of triterpenoids isolated from Ficus benjamina leaves. An unsaponified fraction of petroleum ether extract of plant leaves was subjected to silica gel column chromatography which led to the isolation of two known triterpenoids; namely ursolic acid and lupeol. These compounds were evaluated for antiplasmodial activity by schizont maturation inhibition assay using 3D7 Plasmodium strains. Both, ursolic acid and lupeol were found to exhibit significant antiplasmodial effect with an IC50 value of 18 µg/ml and 3.8 µg/ml, respectively. This study further confirms the traditional role of Ficus benjamina plant in the treatment of malaria which may be attributed to ursolic acid and lupeol.

Effects of Different Methods of Isolation on Volatile Composition of Artemisia annua L.

In order to determine influence of extraction method on volatile oil composition of Artemisia annua L., steam distillation, hydrodistillation, organic solvent extraction, and headspace sampling have been applied. The relative abundance of volatile compounds from the odorous aerial parts of A. annua, obtained by different extraction techniques, was analyzed by GC-MS. Exactly fifty constituents were identified. The leaf and flower essential oil yield ranged from 0.9 to 2.3% (v/w). Oxygenated monoterpenes were predominant in all samples ranged from 42.6% for steam-distilled fraction of petroleum ether extract to 70.6% for headspace of plant material. Essential oils isolated by steam distillation and hydrodistillation indicate that A. annua belongs to artemisia ketone chemotype with its relative content of 30.2% and 28.3%, respectively. The principal constituent in headspace sample of plant material was also artemisia ketone (46.4%), while headspace of petroleum ether extract had camphene (25.6%) as the major compound. The results prove the combined approaches to be powerful for the analysis of complex herbal samples.

Phytochemical analysis of successive extracts of the Cordia macleodii leaves Hook.: A Folklore medicinal plant

‘Preliminary phytochemical analysis of successive extracts, fluorescence analysis and HPTLC of C. macleodiileaves has been planned in the current study.’ The extracts of the dried coarse powdered of C. macleodii leaves obtained using different polarities solventsin succession were tested for the presence of various active phytoconstituents. Fluorescence analysis was investigated andunsaponifiable fraction of petroleum ether extract was also observed forchromatographic evaluations. The outcome suggest that the existence of various dynamic phytoconstituents having particular solubility in selected solvents of different polarities used in succession. The fluorescent analysis under the visible and UV light by treatment of diverse chemical reagents showed diverse colours. HPTLC profile of unsaponifiable fraction showed 10 and 3 spots at 254 nm and 366 nm radiation respectively. After spraying with diluted H2SO4, it showed 5 and 6 spots at 254 nm and 366 nm radiations respectively. The presence of active constituents in different polarities solvent, which were used in progression suggesting the significance of the solvent as a conclusive factor. Further the data suggests that, the successive extractions using Petroleum ether, chloroform, methanol and water solvents of different polarities would maximize the exploitation of the diverse bioactive compounds. Study concluded that it would be help to isolate and characterize the different pharmacologically dynamic principles of the C. macleodii such as mouth sores, treating jaundice, hepatoprotective and also as an aphrodisiac. It shows their importance for supporting their claimed uses and biological activities such as wound healing.

Bioassay Guided Fractionation and in vitro Anti-plasmodial Activity of Ficus deltoidea and Ficus benjamina

Background: Malaria is infectious vector born disease affecting 212 million people belonging to 97 countries globally in the year 2016. Although this number has reduced progressively from last one decade but recent failure of currently available antimalarial drug therapy has accentuated the urgent need to explore different novel approaches in Anti-plasmodial drug discovery. Objective: The aim of the present study was to evaluate the Anti-plasmodial activity of traditional medicinal plants Ficus deltoidea and Ficus benjamina. Materials and Methods: Crude petroleum ether and hydro alcoholic extract of both the plant species were evaluated for Anti-plasmodial activity by schizont maturation inhibition assay using 3D7 plasmodium strains. Results: It was observed that petroleum ether extract of F. benjamina leaves showed most promising inhibitory effect on the growth of schizonts with IC50 14.5 μg/ml. Bio-assay guided fractionation of petroleum ether extract of F. benjamina led to the hexane and chloroform fraction with high Anti-plasmodial activity (IC50 4.0 μg/ml and IC50 7.8 μg/ml respectively). Further, phytochemical investigation of F. benjamina indicated the presence of various valuable phytochemicals belonging to class of steroids, terpenoids and phytosterols. Conclusion: This study has revealed the Anti-plasmodial activity of F. deltoidea and F. benjamina for the first time. Significant Anti-plasmodial activity and preliminary phytochemical studies of F. benjamina indicates its rich chemical diversity which make this plant a good candidate for isolating new molecule that could serve as new lead in Anti-plasmodial drug discovery.

Insecticidal activity of different fractions of petroleum ether extract of Zingiber cassumunar rhizome against Tribolium castaneum

An experiment was carried out to investigate the efficacy of contact toxicity of different fractions of petroleum ether extract of Zinziber cassumunar Roxb. rhizome against Tribolium castaneum. Seventy-eight different fractions of petroleum ether extract were obtained from column chromatography. Elutes having the similar TLC behavior were combined in eight fractions and were named as: MN-1, MN-2, MN-3, MN-4, MN-5, MN-6, MN-7 and MN-8. Four separate fractions were collected from the MN-1 fraction by preparative thin layer chromatography. These four parts were washed with petroleum ether, chloroform, ethyl acetate and methanol. Thereafter, these were separated by small column and designated as: M1N1, M1N2, M1N3, M1N4, M2N1, M2N2, M2N3, M2N4, M3N1, M3N2, M3N3, M3N4, M4N1 and M4N2. Fractions of M1N2, M2N2, M3N2 and M4N2 were found to be the most effective against the beetle T. castaneum after 24, 48 and 72 hours. However, some fractions exhibited the moderate effect and other fractions did not work against the beetle.Bangladesh J. Sci. Ind. Res. 50(2), 143-152, 2015

Isolation and biological evaluation of novel Tetracosahexaene hexamethyl, an acyclic triterpenoids derivatives and antioxidant from Justicia adhatoda.

Forty five extracts fraction of nine selected Indian medicinal plants, based on their use in traditional systems of medicine were analyzed for their antioxidant potential. All the extracts were investigated for phenol content value calculated in Gallic acid equivalents (% of GAE) and antioxidant potential. Moreover, total phenolic content (% dw equivalents to gallic acid) of all plant extracts were found in the range of 3.04 to 24.03, which correlated with antioxidant activity. The findings indicated a promising antioxidant activity of crude extracts fractions of three plants (Justicia adhatoda, Capparis aphylla and Aegle marmelos) and required the further exploration for their effective utilization. Results indicated that petroleum ether fraction of J. adhatoda out of three plants also possesses the admirable antioxidant abilities with high total phenolic content. Following, in vitro antioxidant activity-guided phytochemical separation procedures, twelve fractions of petroleum ether extract of J. adhatoda were isolated by silica gel column chromatography. One fraction (Rf value: 0.725) showed the noticeable antioxidant activity with ascorbic acid standard in hydroxyl radical scavenging assays. The molecular structures elucidations of purified antioxidant compound were carried out using spectroscopic studies ((1)H NMR, (13)C NMR and MS). This compound was reported from this species for the first time. The results imply that the J. adhatoda might be a potential source of natural antioxidants and 2,6,10,14,18,22-Tetracosahexaene, 2,6,10,15,19,23-hexamethyl is an antioxidant ingredient in J. adhatoda.

Anticancer Activity of Carica papaya Extracts in vito and Phytochemical Analysis

The aim of the present work is the evaluation of anti cancer effect of Carica papaya aerial parts extracts and also the investigation of the phytoconstituents from the extracts of the plant. Petroleum ether (40-60 о C), Chloroform, ethyl acetate and methanol 80% extracts of C. papaya aerial parts were tested for their anti cancer activity on three cancer cells TK10 (renal), UACC62 (melanoma) and MCF7 (breast) cancer cells using a Sulforhodamine B (SRB) assay. Petroleum ether of C. papaya at the concentration of 100 µg/ml has shown a significant anticancer effect for MCF7 (breast) cancer cells and showed less anticancer effect for the other two cancer cells while the other extracts have mild anticancer effect on the three cancer cells. Phytochemical profile of the plant extracts proves the presence of flavonoids, tannins, alkaloids, carbohydrates and triterpenes and bioactive fractionation of petroleum ether extract revealed the isolation and identification of β-sitosterol, stigmasterol as the major constituents. The results suggest that petroleum ether extract of C. papaya exhibited a significant anti cancer activity for breast cancer.

The Compositional Features of Thermally Soluble Fractions from Two Chinese Coals in Cyclohexane

Shengli lignite (SL) and Shenmu-Fugu subbituminous coal (SFSBC) were subjected to thermal dissolution in cyclohexane at 300°C for 1 h under hydrogen. The reaction mixtures were extracted with petroleum ether (PE) and the PE-extractable fractions (PEEFs) were analyzed with a gas chromatography/mass spectrometer. The results show that the PEEFs from thermally dissolved SL (TDSL) and thermally dissolved SFSBC (TDSFSBC) mainly consist of alkanes, alkenes, arenes, and oxygen-containing organic compounds (OCOCs); the yields of alkanes and alkenes in the PEEF from TDSFSBC are appreciably higher than those from TDSL, while the yields of arenes and oxygen-containing organic compounds in the petroleum ether-extractable fraction from thermally dissolved Shenmu-Fugu subbituminous coal are significantly lower than those from thermally dissolved Shengli lignite; arenols are dominant OCOCs in the PEEF from TDSL, while main OCOCs in the PEEFs from TDSFSBC are arenols and esters.

Algicidal activity and potential mechanisms of ginkgolic acids isolated from Ginkgo biloba exocarp on Microcystis aeruginosa

Natural plant agents are considered promising sources to control harmful algal blooms. The primary purpose of this study was to isolate the algicidal compounds from Ginkgo biloba exocarp against the toxic cyanobacterium Microcystis aeruginosa and determine the potential inhibition mechanisms. Bioassay-guided fractionation of petroleum ether extract yielded ginkgolic acids, which were identified by spectral analysis (infrared and reversed-phase high-performance liquid chromatography/electrospray mass spectrometry). Bioassays showed ginkgolic acids inhibited M. aeruginosa growth effectively with the 3- and 7-day median effective concentration (EC50,3d, EC50,7d) of 3.26 and 2.03 mg L−1, respectively. For the potential inhibition mechanisms, cellular morphology, physiological changes, and genes expression during 12–96 h of exposure were investigated. Ginkgolic acids caused morphologic damage or lysis of cells. They induced oxidative damage by increasing malondialdehyde content and decreasing total antioxidant and superoxide dismutase activities. Transcription of three photosynthetic genes (psaB, psbD, and rbcL) and two nutrient uptake related genes (ntcA and phoU) were also found to be inhibited. Additionally, ginkgolic acids also affected the microcystin contents and the transcription of microcystin-related genes. The results suggested that ginkgolic acids isolated from G. biloba exocarp have the potential to inhibit M. aeruginosa growth effectively by causing pleiotropic effects on several physiological and biochemical reactions.

Phytochemical properties of some solvent fractions of petroleum ether extract of the African mistletoe (Loranthus micranthus Linn) leaves and their antimicrobial activity

The leaves of the African Mistletoe (Loranthus micranthus Linn) on Kola acuminata in Nsukka, Eastern Nigeria were studied. The chloroform (A), ethyl acetate (B) and ethyl acetate residue (C) fractions of crude petroleum ether extract of L. micranthus Linn were subjected to phytochemical and antimicrobial evaluation. Results reveal the presence of protein in fraction C, whereas flavonoids, steroids and terpenes were present in all the fractions, but in a low quantity. Fractions A and B had high, while fraction C had moderate quantity of tannins. However, high quantity of resins was present in fraction C followed by fraction A. Fraction B showed the highest susceptibility (25) to Bacillus subtilis , and was active against the fungus, Candida albicans, suggesting its higher potency and fungistatic potential. Apart from Klebsiella spp., the other organisms were not susceptible to fraction A, apparently owing to high resins but no protein content. Fraction C was active against the highest number of organisms ( Pseudomonas aeruginosa , B. subtilis and Klebsiella spp.). In all, this study suggests that A, B and C fractions of crude petroleum ether leaf extract of L. micranthus Linn is parasitic on K. acuminate , may serve as source for compounds with therapeutic potentials. However, the fractionating solvents used in this study may not be the preferred choice for fractionating the active principles of L. micranthus Linn. Interestingly, the possible fungistatic potential of L. micranthus Linn parasitic on K. acuminata as observed in fraction B may be exploited in the design and development of fungistatic drug. Keywords: Phytochemical, antimicrobial, fungistatic, Loranthus micranthus Linn, Kola acuminata , mistletoe

Larvicidal efficacy of Ocimum basilicum extracts and its synergistic effect with neonicotinoid in the management of Anopheles stephensi

ObjectiveTo evaluate the larvicidal activities of different combinations of synthetic nicotinoid insecticide, imidacloprid with an insecticidal plant, Ocimum basilicum (O. basilicum) against malaria vector, Anopheles stephensi, with reference to the impact of most potent combination on some non-targets, Anisops bouvieri (A. bouvieri) and cyclop. MethodsThe larvicidal activity was determined against mosquito larvae in various concentrations, 1:1, 1:2 and 1:4 under laboratory conditions. These experiments were conducted according to WHO standard procedure. ResultsIn bioassays, binary mixtures of different combinations of synthetic insecticide (imidacloprid) with crude petroleum ether leave extract of O. basilicum and then with most potent 4th fraction of it, produced promising results. Therefore, ratio 1:1 of all the binary mixtures was most effective as compared to 1:2 and 1:4 against mosquito larvae and showed synergism in all cases. The combinatorial ratio 1:1 of imidacloprid and most potent 4th fraction of petroleum ether extract of O. basilicum with LC50 value 0.010 and 0.007 ppm; LC90 value 0.033 and 0.023 ppm for anopheline larvae after 24 and 48 h of treatment, respectively, showed high toxicity. This effective ratio was found safe to aquatic mosquito predator, A. bouvieri and other aquatic non-target cyclops with the respective LC50 values 12.351 and 5.290 ppm after 24 h of exposure. ConclusionsIt is, therefore, concluded that the tested combination is more effective than its individual constituents. Further, this formulation is cost-effective and ecofriendly to the aquatic fauna.

Egbuonu, A.C.C., Nwankwo N.E. (2012). Phytochemical of some solvent fractions of petroleum ether extract of the African Mistletoe (Loranthus micranthus Linn) leaves and their antimicrobial activity

Egbuonu, A.C.C., Nwankwo N.E. (2012). Phytochemical of some solvent fractions of petroleum ether extract of the African Mistletoe (Loranthus micranthus Linn) leaves and their antimicrobial activity

AKTIVITAS SITOTOKSIK ISOLAT 5 FRAKSI ETIL ASETAT EKSTRAK PETROLEUM ETER DAUNPhaleria macrocarpa(Scheff.) Boerl. PADA TURUNAN SEL KANKER SERVIKS MANUSIA (HeLa)

Cervical cancer is a malignant tumor in cervix which is occupy the second possition that cause the death of Indonesia’s women under the breast cancer. One of the traditional medicine that can be used to cure cancer is Phaleria macrocarpa (Scheff.)Boerl leaves. The petroleum eter extract of Phaleria macrocarpa (Scheff.)Boerl leaves has antiproliferation activity againts cervical cancer cell lines (HeLa) with IC50 9 µg/ml (Kintoko & Azimahtol Hawariah, 2007). This research was aimed to detect cytotoxic activity of isolate 5 of ethyl acetate fraction of petroleum ether extract of Phaleria macrocarpa (Scheff.)Boerl leaves againts HeLa cell lines. Initially, the powder of Phaleria macrocarpa (Scheff.)Boerl was extracted using Soxhlet apparatus with petroleum ether. The extracts was concentrated and partitioned until ethyl acetate fraction was obtained. The fraction of ethyl acetate was isolated using Preparative Thin Layer Chromatography on silica gel F254 as stationary phase and n-hexane : ethyl acetate (9 : 1) as mobile phase. Cytotoxic activity against HeLa cell lines was determinated by LC50 value by direct counting. The isolation by preparative thin layer chromatography resulted five isolate on Rf value : 0,05 ; 0,10 ; 0,20 ; 0,60 ; and 0,90. The LC50 values of isolate 5 (Rf : 0,90) was 123,60 µg/ml.

Mosquito larvicidal activity of oleic and linoleic acids isolated from Citrullus colocynthis (Linn.) Schrad

In mosquito control programs, botanical origin may have the potential to be used successfully as larvicides. The larvicidal activity of crude acetone, hexane, ethyl acetate, methanol, and petroleum ether extracts of the leaf of Centella asiatica Linn., Datura metal Linn., Mukia scabrella Arn., Toddalia asiatica (Linn.) Lam, extracts of whole plant of Citrullus colocynthis (Linn.) Schrad, and Sphaeranthus indicus Linn. were assayed for their toxicity against the early fourth instar larvae of Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in whole plant petroleum ether extract of C. colocynthis. In the present study, bioassay-guided fractionation of petroleum ether extract led to the separation and identification of fatty acids; oleic acid and linoleic acid were isolated and identified as mosquito larvicidal compounds. Oleic and Linoleic acids were quite potent against fourth instar larvae of Aedes aegypti L. (LC50 8.80, 18.20 and LC90 35.39, 96.33 ppm), Anopheles stephensi Liston (LC50 9.79, 11.49 and LC90 37.42, 47.35 ppm), and Culex quinquefasciatus Say (LC50 7.66, 27.24 and LC90 30.71, 70.38 ppm). The structure was elucidated from infrared, ultraviolet, 1H-nuclear magnetic resonance, 13C-NMR, and mass spectral data. This is the first report on the mosquito larvicidal activity of the reported isolated compounds from C. colocynthis.

Effect of Aerva lanata against hepatotoxicity of carbon tetrachloride in rats

The partially purified petroleum ether extractable fraction of the whole plant Aerva lanata (PF) was evaluated for the protective effect against liver damage induced by carbon tetra chloride (CCl 4) in Sprague Dawley rats. Rats were orally administered with PF (50 and 100 mg/kg body weight) for 14 days before CCl 4 challenge and 100 mg of PF alone for toxicity analysis without CCl 4 administration. The results showed that CCl 4 administration significantly damaged the liver as evident from histopathology and very high activity of serum and liver marker enzymes. It also reduced the antioxidant enzyme status of the animals. PF administration significantly reversed the histopathological changes and restored the elevated activities of liver marker enzymes and also enhanced the antioxidant enzyme activities. The extract also reduced hepatic lipid peroxidation and increased the serum total protein and albumin/globulin (A/G) ratio. Preliminary phytochemical analysis of PF showed the presence of alkaloids. These observations clearly indicate that PF contains antioxidant alkaloids capable of ameliorating the CCl 4-induced hepatic injury by virtue of its antioxidant activity.

THE EFFECT OF GARLIC IN PREVENTION AND CONTROL OF CARDIOVASCULAR DISORDERS

The aim of this review was to evaluate the effect of different preparations of garlic with different methodologies on prevention and control of cardiovascular disorders. Almost 30 articles and abstracts from 1990-2003 were searched through Medline. Most of the studies between 1990-1993 showed the significant reduction of TC by garlic powder but a recent controlled study in 2000 found that consumption of 900 mg of dried garlic powder for 12 weeks by hypercholesterolemic subjects did not have any significant effect on TC, LDL-C and HDL-C. The evidences of some double-blinded randomized placebo-controlled or crossover interventions indicated that aged garlic extract (AGE) inhibits the oxidation of LDL, aggregation and adhesion of platelets in a dose-dependent manner. In one animal study using cultured rat hepatocyte it was found 44-87% inhibition of cholesterol synthesis by the water-extractable fraction (WEE) methanol-extractable fraction (MEF) and petroleum ether-extractable fraction of fresh garlic and liquid form of AGE. In recent study in 2003 AGE found to be an effective antioxidant as it scavenged superoxide ions and reduced lipid peroxides in cell free assays. Standard formulations such as AGE has a role in preventing the development and progression of atherosclerotic disease but more controlled studies are warranted.

Larvicidal and chemosterilant activity of the acetone fraction of petroleum ether extract from Argemone mexicana L. seed

The acetone fraction of the petroleum ether extract of seeds from Argemone mexicana L. exhibited larvicidal and growth inhibiting activity against the second instar larvae of Aedes aegypti (Linn). This activity occurred at higher concentrations (200, 100, 50 and 25 ppm). Chemosterilant activity, including reduction in blood meal utilization (27.70%), reduction in fecundity (19.00%), formation of larval–pupal intermediates, formation of pupal–adult intermediates, adult mortality and sterility of first generation eggs (100%), occurred at low concentration (10 ppm).

Cholesterol-Lowering Effect of Garlic Extracts and Organosulfur Compounds: Human and Animal Studies

The medicinal use of garlic dates back thousands of years, but there was little scientific support of its therapeutic and pharmacologic properties until recently. In the past decade, the cancer-protective effects of garlic have been well established by epidemiologic studies and animal experiments. However, the cardiovascular-protective properties of garlic are less well understood. In particular, despite the reported hypocholesterolemic effect of garlic, the mechanism of the effect is unclear. In a recent randomized, double-blind, placebo-controlled intervention study, we showed that aged garlic extract (AGE) supplementation was effective in lowering plasma concentration of total cholesterol by 7% and LDL cholesterol by 10% in hypercholesterolemic men compared with subjects consuming a placebo. Supplementation of AGE in animal diets similarly reduced plasma concentrations of total cholesterol and triacylglycerol by 15 and 30%, respectively. In subsequent experiments using cultured rat hepatocytes, we found 44--87% inhibition of cholesterol synthesis by the water-extractable fraction (WEF), methanol-extractable fraction (MEF) and petroleum ether-extractable fraction (PEF) of fresh garlic, and Kyolic (liquid form of AGE). These observations suggested that hydrophilic and hydrophobic compounds of garlic are inhibitory to cholesterol synthesis. Because S-allylcysteine (SAC) alone was less potent than Kyolic, which contains SAC and other sulfur compounds, a maximal inhibition appears to require a concerted action of multiple compounds of garlic. In a series of experiments, we further characterized the inhibitory potency of individual water-soluble and lipid-soluble compounds of garlic. Among water-soluble compounds, SAC, S-ethylcysteine (SEC), and S-propylcysteine (SPC) inhibited cholesterol synthesis by 40--60% compared with 20--35% by gamma-glutamyl-S-allylcysteine (GSAC), gamma-glutamyl-S-methylcysteine (GSMC) and gamma-glutamyl-S-propylcysteine (GSPC). Lipid-soluble sulfur compounds (i.e., diallyl sulfide, diallyl disulfide, diallyl trisulfide, dipropyl sulfide and dipropyl trisulfide) at low concentrations (0.05--0.5 mol/L) slightly (10--15%) inhibited cholesterol synthesis but became highly cytotoxic at high concentrations (1.0--4.0 mol/L). All water-soluble compounds, except S-allylmercaptocysteine, were not cytotoxic, judging from the release of cellular lactate dehydrogenase into the culture medium. Taken together, the results of our studies indicate that the cholesterol-lowering effects of garlic extract, such as AGE, stem in part from inhibition of hepatic cholesterol synthesis by water-soluble sulfur compounds, especially SAC.