Isolation Of Active Compounds Research Articles

TLC-bioautography linked with guess: A truely targeted active compound isolation process

In order to optimize the isolation procedure of anti-TB lead compounds, a truly targeted isolation approach was developed, which aligns (HP)TLC-bioautography with GUESS1 based countercurrent separation (CCS). (HP)TLC-bioautography was specifically developed for Mycobacterium tuberculosis, using the mc2 7000 lux ABCDE strain, while the GUESS method is used to rapidly determine the optimal CCS solvent system. Optimal CCS conditions target the separation of the inhibition zones within a range of optimal CCS partition coefficients referred to as the “CCS sweet spot”, with a corresponding TLC Rf-value ˜0.5. Hereby, the CCS solvent system is chosen on the basis of the Rf-value of the bioactive component(s) rather than the fraction as a whole. This approach accelerates the isolation process and prevents the isolation of non-active metabolites and byproducts. The new TLC-bioautography-GUESS-CCS workflow is demonstrated with the fractionation of an extract from an anti-TB active actinomycete strain. [Funding: NIH R21 AI093919 – 02] 1Friesen & Pauli, G.U.E.S.S. – A Generally Useful Estimate of Solvent Systems for CCC, Journal of Liquid Chromatography & Related Technologies, 2005, Volume 28, Issue17, 2777 – 2806 *Equal contributors

Antioxidant and antitumour activities of extracts from Patrinia villosa and its active constituents

Patrinia villosa Juss is a famous medicinal herb and is used as an anti-inflammatory and anti-bacterial agent. Its tender leaves have also been used as a wild vegetable in China. In this study, the antioxidant and cytotoxic activities of various fractions of ethanol extract from P. villosa were investigated, the ethyl acetate fraction (EE-PV) exhibited the strongest antioxidant activity and cytotoxic effect on four cancer cell lines. EE-PV also significantly inhibited the tumour growth in vivo. EE-PV was subjected to bioassay-guided isolation of active compounds by column chromatography. Phenolic compounds such as 5,7,4′-trihydroxy-3-methoxyflavone and p-hydroxybenzoic acid are mainly responsible for antioxidant activity. Ursolic acid as one of main constituents contributed to the antitumour activity of EE-PV. These results suggest that this plant extract could be considered as a potential source of functional food and pharmaceutical for preventing cancer and reducing the risk of chronic diseases associated with oxidative damage.

Antibacterial assay-guided isolation of active compounds from Artocarpus heterophyllus heartwoods

Context: Preparations from Artocarpus heterophyllus Lam. (Moraceae) heartwoods are used in the traditional folk medicine for the treatment of inflammation, malarial fever, and to prevent bacterial and fungal infections.Objective: The objective of this study was to isolate pure antibacterial compounds from A. heterophyllus heartwoods.Materials and methods: The dried and powdered A. heterophyllus heartwoods were successively extracted with the following solvents: hexane, ethyl acetate, and methanol. Each of the extracts was screened for their antibacterial activities using a disc diffusion method (10 mg/disc). Their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined using a broth microdilution method. The extract that showed the strongest antibacterial activities was fractionated to isolate the active compounds by an antibacterial assay-guided isolation process.Results and discussion: The ethyl acetate extract exhibited the strongest antibacterial activities against Streptococcus mutans, S. pyogenes, and Bacillus subtilis with MIC values of 78, 39, and 9.8 µg/mL, respectively. Based on an antibacterial assay-guided isolation, four antibacterial compounds: cycloartocarpin (1), artocarpin (2), artocarpanone (3), and cyanomaclurin (4) were purified. Among these isolated compounds, artocarpin exhibited the strongest antibacterial activity against Gram-positive bacteria, including S. mutans, S. pyogenes, B. subtilis, Staphylococcus aureus, and S. epidermidis with MICs of 4.4, 4.4, 17.8, 8.9, and 8.9 µM, respectively, and MBCs of 8.9, 8.9, 17.8, 8.9, and 8.9 µM, respectively, while artocarpanone showed the strongest activity against Escherichia coli, a Gram-negative bacteria with MIC and MBC values of 12.9 and 25.8 µM, respectively. Only artocarpin showed inhibitory activity against Pseudomonas aeruginosa with an MIC of 286.4 µM.

<b>Phytotoxic effects of aqueous leaf extracts of four Myrtaceae species on three weeds

Research on allelopathic interactions can be useful in the search for phytotoxins produced by plants that may be employed as natural herbicides. The aim of this study was to assess the phytotoxic action of aqueous leaf extract of Blepharocalyx salicifolius, Myrcia multiflora, Myrcia splendens and Myrcia tomentosa on the germination and development of three weeds. The working hypothesis was that leaf extracts of Myrtaceae may negatively influence the development of weed species. Aqueous leaf extracts at 5 and 10% (g mL-1) were tested on the germination and growth of Euphorbia heterophylla, Echinochloa crus-galli and Ipomoea grandifolia and compared with the herbicide oxyfluorfen and distilled water (control). The most extracts caused pronounced delays in seed germination and inhibited the growth of seedlings of E. heterophylla; I. grandifolia and E. crus-galli, with the last target species had no growth shoot inhibited by the extracts. In this study, the potential and efficiency of the tested aqueous leaf extracts were evident because they were more phytotoxic to the weeds than the herbicide. Thus, the aqueous extracts of leaves from Myrtaceae species show potential for the isolation of active compounds that can be used for the production of natural herbicides in the future.

Differential anti-insect activity of natural products isolated from Dodonaea viscosa Jacq. (Sapindaceae)

Abstract Botanical biopesticides constitute an important tool for Integrated Pest Management practices. Uruguay has a great potential for developing botanical biopesticides from its abundant native flora. Dodonaea viscosa Jacq. is a native Sapindaceae that in preliminary studies was shown to possess a potential deterrent activity against insect models. In this work, ethanolic extracts of the leaves of this species were studied. Bioguided fractionation and supercritical fluid extraction led to the isolation of active compounds. For that purpose four insect models were used: Epilachna paenulata, Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, which are pests of crops of economic importance. Lupeol, stigmasterol, stigmast-7-en-3-ol, and a labdane diterpene were isolated and showed differential activity against the models.

Anti-inflammatory flavanol glycosides from Saraca asoca bark

Saraca asoca (Roxb.) de Wilde, a common tree of India, is popularly used in the Ayurvedic and modern herbal systems of medicine for genito-urinary problems of women. Considering the reported antimicrobial or anti-inflammatory effect of S. asoca bark against such infections, we studied the anti-inflammatory activity-guided isolation of active compounds from methanol extract. The methanol extract of bark has yielded 10 compounds out of which 3′-deoxyepicatechin-3-O-β-d-glucopyranoside (6) and 3′-deoxycatechin-3-O-α-l-rhamnopyranoside (8) have been found to be in vitro and in vivo active. 3′,5-Dimethoxy epicatechin (3), 3′-deoxyepicatechin-3-O-β-d-glucopyranoside (6), 3′-deoxycatechin-3-O-α-l-rhamnopyranoside (8) and epigallocatechin (9) are being reported for the first time from S. asoca.

Analysis of Bioactive Components of Oilseed Cakes by High-Performance Thin-Layer Chromatography-(Bio)assay Combined with Mass Spectrometry

Hemp, flax and canola seed cakes are byproducts of the plant oil extraction industry that have not received much attention in terms of their potential use for human food instead of animal feed. Thus, the bioactivity profiling of these oilseed cakes is of interest. For their effect-directed analysis, planar chromatography was combined with several (bio)assays, namely 2,2-diphenyl-1-picrylhydrazyl scavenging, acetylcholine esterase inhibition, planar yeast estrogen screen, antimicrobial Bacillus subtilis and Aliivibrio fischeri assays. The streamlined high-performance thin-layer chromatography (HPTLC)-bioassay method allowed the discovery of previously unknown bioactive compounds present in these oilseed cake extracts. In contrast to target analysis, the direct link to the effective compounds allowed comprehensive information with regard to selected effects. HPTLC-electrospray ionization-mass spectrometry via the elution-head based TLC-MS Interface was used for a first characterization of the unknown effective compounds. The demonstrated bioactivity profiling on the feed/food intake side may guide the isolation of active compounds for production of functional food or for justified motivation of functional feed/food supplements.

English

Tanzania has over 12,000 plant species, some of which are endemic and have potential to yield useful medicines. This study seeks to document such plants used as traditional medicines for treatment of malaria in Kagera region of northwestern Tanzania and Lindi region in south eastern Tanzania. The study also reports on the antiplasmodial activity against chloroquine-resistant Plasmodium falciparum (Dd2) strain of some of the documented plants using the parasite lactate dehydrogenase method. A total of 108 plant species, among which the families Compositae (14; 12.96%), Fabaceae (12; 11.11%), Euphorbiaceae (8; 7.41%), Melastomataceae (6; 5.56%) and Myrtaceae (4; 3.70%) were documented. Sixteen (16; 44.4%) of 36 extracts from 31 plant species that were tested inhibited malaria parasites growth by more than 50%. Bersema abyssinica stem bark extract was the most active with 86.67% inhibition rate followed by Bridelia micrantha stem bark extract with 71.87% inhibition rate. These results confirm the potential for plants used in traditional medicine to yield active antimalarial compounds. Further in vitro and in vivo screening supported by bioassay-guided isolation of active compounds from plants showing good safety margin is suggested. Key words: Ethnobotanical survey, medicinal plants, malaria, treatment, in vitro antiplasmodial, Tanzania.

Evaluation of Phyllanthus polyphyllus L. Extract and its Active Constituent as a Source of Antifungal, Anti-Aflatoxigenic, and Antioxidant Activities

The present investigation was carried out to evaluate the antifungal activities of Phyllanthus polyphyllus L. leaf extract, to isolate its active constituent 4-o-methyl gallic acid (4-o-MGA), and to determine the antioxidant and antiaflatoxigenic properties. The bioassay-guided fractionation of methanol extract led to the isolation of active compound 4-o-methylgallic acid. The methanol extract showed the highest amount of phenolic content (290 mg GAE/g dry extract), which indicated the involvement of phenolic compounds in the radical scavenging activity observed by the methanol extract. The antioxidant capacity of 4-o-MGA was greater than the standard butylated hydroxytoluene, followed by methanol extract. The concentration-dependent growth inhibitory activity was observed against the tested fungi, in which the field fungi were susceptible, while the storage fungi were found to be more resistant including aflatoxigenic A. flavus. A correlation was observed between fungal biomass and aflatoxin production in control and treatment, there was a decrease in biomass of A. flavus and aflatoxin production with increasing concentration. The aflatoxin production was completely inhibited in vitro by methanol extract at 1 mg/mL and 4-o-MGA at 2 mg/mL, but the mycelial growth was not inhibited completely. The inhibition of aflatoxin production was relatively higher than the mycelial growth inhibition of A. flavus, such behaviors might have been determined by the presence of hydrolysable tannin 4-o-MGA in the extract, which is known to inhibit the aflatoxin biosynthesis. The significant antioxidant and aflatoxin inhibitory activities of P. polyphyllus could be exploited for its application in preventing oxidative deterioration and fungal spoilage of food products.

Bioassay-guided isolation of Poliovirus-inhibiting constituents from Zephyranthes candida

Context: Plants of the Zephyranthes genus are globally used in folk medicine. In a previous study, Zephyranthes candida Linn. (Amaryllidaceae) was identified as having antiviral properties; this led to anti-poliovirus assay-guided isolation of compounds from crude methanol extract of the plant.Objective: Isolation of anti-poliovirus constituents from Z. candida.Material and methods: Active chloroform fraction from crude methanol extract of Z. candida (whole plant) was subjected to bioassay-guided fractionation; repeated column and preparative thin layer chromatography led to isolation of active compounds. Chemical structures were identified using spectroscopic techniques. Using serial two-fold dilution of maximum non-toxic concentration (MNTC) of each compound (0.0625–1 µg/mL for lycorine and 0.625–10 µg/mL for trisphaeridine and 7-hydroxy-3′,4′-methylenedioxyflavan), the ability of extracts to inhibit viral-induced cell death in tissue culture was evaluated 72 h post-infection by the colorimetric method using MTT (3-[4,5-dimethylthiazol–2-yl]-2,5-diphenyltetrazolium bromide) dye. Regression analysis was used to determine 50% inhibitory concentration (IC50) and 50% cytotoxicity concentration (CC50), from which selective index (SI) was calculated.Results: From the chloroform fraction, three compounds were isolated and identified, namely lycorine (1), trisphaeridine (2), and 7-hydroxy-3′,4′-methylenedioxyflavan (3) as the anti-polioviral components. Lycorine was the most active, with an IC50 value of 0.058 µg/mL followed by trisphaeridine (2) with an IC50 of 0.1427 µg/mL, and 7-hydroxy-3′,4′-methylenedioxyflavan (3) with an IC50 of 0.2384 µg/mL.Discussions and conclusions: The antipoliovirus activity of trisphaeridine (2) and 7-hydroxy-3′,4′-methylenedioxyflavan (3) is established in this report; these compounds are of moderate toxicity and have very good SI. They could be a potential template for the development of a new antiviral agent.

Alkaline phosphatase activity-guided isolation of active compounds and new dammarane-type triterpenes from Cissus quadrangularis hexane extract

Ethnopharmacological relevanceThe stem of Cissus quadrangularis L. (CQ) is used in traditional medicine to treat bone fractures and swelling. Anti-osteoporotic activity of CQ hexane extract has been reported, but the active compounds in this extract remain unknown. Thus, we aimed to identify the active compounds in CQ hexane extract using bioassay-guided isolation. Materials and methodsThe CQ hexane extract was fractionated sequentially with benzene, dichloromethane, ethyl acetate, and methanol. The examination of CQ extract and its fractions was guided by bioassays for alkaline phosphatase (ALP) activity during the differentiation of MC3T3-E1 osteoblastic cells. The cells were treated with or without the CQ extract and its fractions for a period of time, and then the stimulatory effect of the alkaline phosphatase enzyme, a bone differentiation marker, was investigated. The compounds obtained were structurally elucidated using spectroscopic techniques and re-evaluated for activity during bone differentiation. ResultsA total of 29 compounds were isolated, viz., triterpenes, fatty acid methyl esters, glycerolipids, steroids, phytols, and cerebrosides. Four new dammarane-type triterpenes were isolated for the first time from nature, and this report is the first to identify this group of compounds from the Vitaceae family. Seven compounds, viz., glycerolipids and squalene, stimulated ALP activity at a dose of 10μg/mL. Moreover, the synergistic effect of these compounds on bone formation was demonstrated. ConclusionThis report describes, for the first time, the isolation of active compounds from CQ hexane extract; these active compounds will be useful for the quality control of extracts from this plant used to treat osteoporosis.

An appraisal of the potency of roots of <i>Anogeissus leiocarpus</i> (DC.) Guill. & Perr. and <i>Terminalia glaucescens</i> Benth. in the management of <i>E</i>. coli related infections

Objective: This study analysed the roots of Anogeissus leiocarpus and Terminalia glaucescens for their chemical constituents and investigated their therapeutic potential in Escherichia coli related infections with a view to combating resistant strains and providing basis for future pharmacological research on the two plants. Methodology and results: The phytochemical analysis of the powdered plant samples was done using qualitative technique. The water and ethanol extracts of the two plants were prepared using cold extraction method. An extract concentration of 10 mg/ml was employed for the antibacterial screening using agar-well diffusion method. The test organisms were clinical isolates of E. coli obtained from the University College Hospital (UCH), Ibadan, Nigeria. All data were statistically analysed. The plants contained alkaloids, saponins, tannins, phenols and glycosides. Seventy (70) % of the test organisms were susceptible to the water extracts of both plants at 10-6 cfu/ml inoculum concentration of isolates. The ethanol extracts of the plants were active against 100 % of the organisms at 10-6 cfu/ml. Conclusion and application of results: The plants have significant therapeutic potential in the management of E. coli associated infections. The isolation of active compounds from the two plants and the study of their mode of actions in infections could lead to the discovery of novel phytodrugs that could be useful in combating multidrug resistant strains of E. coli. The roots of the two plants are sold as chewing sticks (for the prevention of oral infections and mouth odour) in Nigeria. This study indicates the possible antibacterial activity of the plants against oral microbes hence they could be useful in the prevention of tooth decay, gum and throat infections. In addition, the antioxidant screening of the plants could form basis for the assessment of their therapeutic potential in the management of metabolic diseases such as diabetes. The roots of the two plants are commonly used in ethnomedicine in Nigeria; therefore efforts should be directed at their sustainable use via conservation.Keywords: Anogeissus leiocarpus; Terminalia glaucescens; herbal recipe; Escherichia coli; antibacterial activity; phytochemical analysis.

Bioassay-guided isolation of active compounds and fingerprinting of an edible nut toward the development of a diabetic zebrafish model

Bioassay-guided isolation of active compounds and fingerprinting of an edible nut toward the development of a diabetic zebrafish model

Evaluation of the Biological Activities of Marine Bacteria Collected from Jeju Island, Korea, and Isolation of Active Compounds from their Secondary Metabolites

To explore marine microorganisms with medical potential, we isolated and identified marine bacteria from float s, marine algae, animals, and sponges collected from Jeju Island, Korea. We isolated and identified 21 different strains from the marine samples by 16S rRNA analysis, cultured them in marine broth, and extracted them with ethyl acetate (EtOAc) to collect secondary metabolite fractions. Next, we evaluated their anti-oxidative and anti-inflammatory effects. Among the 21 strains, the secondary metabolite fraction of Bacillus badius had both strong antioxidant and anti-inflammatory activity, and thus was selected for further experi ments. An antioxidant compound detected from the secondary metabolite fraction of B. badius was purified by preparative cen trifugal partition chromatography (n-hexane:EtOAc:methanol:water, 4:6:4:6, v/v), and identified as diolmycin A2. Additionally, diolmycin A2 strongly inhibited nitric oxide production. Thus, we successfully identified a significant bioactive compound from B. badius among the bacterial strains collected from Jeju Island.

Vitis amurensis Ruprecht root inhibited α-melanocyte stimulating hormone-induced melanogenesis in B16F10 cells.

BACKGROUND/OBJECTIVESThe root of Vitis amurensis Ruprecht, a sort of wild-growing grape, has been used in oriental medicine for treatment of skin ailments; however, its dermatological activity is not sufficiently understood. The aim of this study was to investigate tyrosinase inhibitory and anti-melanogenic activities of V. amurensis Ruprecht root methanol extract (VARM) in B16F10 mouse melanoma cells and to attempt to isolate and identify the active compound issued from VARM.MATERIALS/METHODSAnti-melanogenic activity of VARM was analyzed in α-melanocyte stimulating hormone (MSH)-stimulated B16F10 cells through evaluation of antioxidative activity as well as inhibited tyrosinase activity and melanin contents compared with those of kojic acid and arbutin. After anti-melanogenic analysis of VARM, serial fractionation, nuclear magnetic resonance (NMR), and thin layer chromatorgraphy (TLC) were applied for identification of active compounds contained in VARM.RESULTSVARM significantly inhibited oxidative stress and tyrosinase activity and attenuated α-MSH-induced melanin production in B16F10 cells. For isolation of active compounds, VARM was fractionated using a series of organic solvents, including dichloromethane (CH2Cl2), ethyl acetate (EtOAc), and n-butanol (n-BuOH). Among fractions showing anti-melanogenic activity, the CH2Cl2 fraction induced the most potent attenuation of melanogenesis without cytotoxicity and the major compound in the CH2Cl2 fraction was identified as betulinic acid. Betulinic acid isolated from the CH2Cl2 fraction of VARM significantly attenuated α-MSH-induced melanogenesis in a dose dependent manner, which was stronger than that of arbutin used as a positive control.CONCLUSIONSThese results indicate that VARM inhibits oxidative stress, tyrosinase activity, and α-MSH-induced melanogenesis in B16F10 cells, due primarily to the active compound, betulinic acid, in the CH2Cl2 fraction.

Discovery of new angiotensin converting enzyme (ACE) inhibitors from medicinal plants to treat hypertension using an in vitro assay

Background and purpose of the studyAngiotensin converting enzyme (ACE) inhibitors plays a critical role in treating hypertension. The purpose of the present investigation was to evaluate ACE inhibition activity of 50 Iranian medicinal plants using an in vitro assay.MethodsThe ACE activity was evaluated by determining the hydrolysis rate of substrate, hippuryl-L-histidyl-L-leucine (HHL), using reverse phase high performance liquid chromatography (RP-HPLC). Total phenolic content and antioxidant activity were determined by Folin-Ciocalteu colorimetric method and DPPH radical scavenging assay respectively.ResultsSix extracts revealed > 50% ACE inhibition activity at 330 μg/ml concentration. They were Berberis integerrima Bunge. (Berberidaceae) (88.2 ± 1.7%), Crataegus microphylla C. Koch (Rosaceae) (80.9 ± 1.3%), Nymphaea alba L. (Nymphaeaceae) (66.3 ± 1.2%), Onopordon acanthium L. (Asteraceae) (80.2 ± 2.0%), Quercus infectoria G. Olivier. (Fagaceae) (93.9 ± 2.5%) and Rubus sp. (Rosaceae) (51.3 ± 1.0%). Q. infectoria possessed the highest total phenolic content with 7410 ± 101 mg gallic acid/100 g dry plant. Antioxidant activity of Q. infectoria (IC50 value 1.7 ± 0.03 μg/ml) was more than that of BHT (IC50 value of 10.3 ± 0.15 μg/ml) and Trolox (IC50 value of 3.2 ± 0.06 μg/ml) as the positive controls.ConclusionsIn this study, we introduced six medicinal plants with ACE inhibition activity. Despite the high ACE inhibition and antioxidant activity of Q. infectoria, due to its tannin content (tannins interfere in ACE activity), another plant, O. acanthium, which also had high ACE inhibition and antioxidant activity, but contained no tannin, could be utilized in further studies for isolation of active compounds.

Isolation of active compounds from methanol extracts of Toddalia asiatica against Ichthyophthirius multifiliis in goldfish (Carassius auratus)

The parasitic ciliate Ichthyophthirius multifiliis infests all species of freshwater fish and can cause severe economic losses in fish breeding. The present study aims to evaluate the antiparasitic activity of the active components from Toddalia asiatica against I. multifiliis. Bioassay-guided fractionation and isolation of compounds with antiparasitic activity were performed on the methanol extract of T. asiatica yielding two bioactive compounds: chelerythrine and chloroxylonine identified by comparing spectral data (NMR and ESI-MS) with literature values. Results from in vitro antiparasitic assays revealed that chelerythrine and chloroxylonine could be 100% effective against I. multifiliis at the concentration of 1.2mgL−1 and 3.5mgL−1, with the median effective concentration (EC50) values of 0.55mgL−1 and 1.90mgL−1 respectively. In vivo experiments demonstrated that fish treated with chelerythrine and chloroxylonine at the concentrations of 1.8 and 8.0mgL−1 carried significantly fewer parasites than the control (P<0.05). The acute toxicity (LC50) of chelerythrine for goldfish was 3.3mgL−1.

Dieckol, a phlorotannin isolated from a brown seaweed, Ecklonia cava, inhibits adipogenesis through AMP-activated protein kinase (AMPK) activation in 3T3-L1 preadipocytes

In this study, we assessed the potential inhibitory effect of 5 species of brown seaweeds on adipogenesis the differentiation of 3T3-L1 preadipocytes into mature adipocytes by measuring Oil-Red O staining. The Ecklonia cava extract tested herein evidenced profound adipogenesis inhibitory effect, compared to that exhibited by the other four brown seaweed extracts. Thus, E. cava was selected for isolation of active compounds and finally the three polyphenol compounds of phlorotannins were obtained and their inhibitory effect on adipogenesis was observed. Among the phlorotannins, dieckol exhibited greatest potential adipogenesis inhibition and down-regulated the expression of peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer-binding proteins (C/EBPα), sterol regulatory element-binding protein 1 (SREBP1) and fatty acid binding protein 4 (FABP4) in a dose-dependent manner. The specific mechanism mediating the effects of dieckol was confirmed by AMP-activated protein kinase (AMPK) activation. These results demonstrate inhibitory effect of dieckol compound on adipogenesis through the activation of the AMPK signal pathway.

Bioprospecting of brown seaweed (Ochrophyta) from the Yucatan Peninsula: cytotoxic, antiproliferative, and antiprotozoal activities

In the Yucatan Peninsula coast, a large diversity of seaweed species are found, and recent studies have reported the presence of metabolites with pharmaceutical importance. In this study, a biological screening of brown seaweed extracts from Dictyota ciliolata, Padina sanctae-crucis, Sargassum fluitans, and Turbinaria tricostata was carried out. Their cytotoxicity and antiproliferative activities were evaluated by the sulforhodamine B assay on human embryonic kidney (HEK 293), human breast cancer (MCF-7), human prostate cancer (LNCaP), and human hepatic cancer (Hep-G2) cell lines. Seaweed extracts were also tested for their anti-trichomonal (Trichomonas vaginalis) and anti-giardicidal (Giardia lamblia) properties. Fucan fractions were extracted using successive maceration with ethanol/water and freeze-dried. Organics extracts were obtained from ethanol residue from liquid–liquid fractionation. A total of four ethanol extracts, four fucan-rich fractions, four ethanolic extracts, and 12 organic fractions were obtained. Only the ethanolic extracts from Turbinaria tricostata and D. ciliolata were active against LNCaP (CC50 of 24.4 and 29.3 μg mL−1, respectively). Interestingly, the activity found in the extracts from D. ciliolata and Turbinaria tricostata was maintained when both extracts were subjected to a liquid–liquid fractionation with hexane on the LNCaP cell line (CC50 of 24.4 and 25.2 μg mL−1, respectively). The antiproliferative assays showed that both dichloromethane and ethanolic fractions from P. sanctae-crucis were active against MCF-7, with IC50 of 26.1 and 29.8 μg mL−1, respectively. These species have been selected for further bio-guided fractionation and isolation of active compounds.

Anti-HIV-1 integrase activity of Mimusops elengi leaf extracts

Context: Integrase (IN) is one of the three human immunodeficiency virus type 1 (HIV-1) enzymes that, together with a reverse transcriptase and protease, allow the virus to reproduce itself after infecting the host cells. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs.Objective: To evaluate the anti-HIV-1 IN activity of some Thai medicinal plant extracts, and to isolate the active compounds from the extract that possessed the strongest anti-HIV-1 IN activity.Materials and methods: Ethanol extracts of eight Thai medicinal plants (10–100 µg/mL) were evaluated for their inhibitory effect against HIV-1 IN. An extract of Mimusops elengi L. (Sapotaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by an anti-HIV-1 IN assay-guided isolation process.Results and discussion: The leaf extract from M. elengi had the strongest anti-HIV-1 IN activity with an IC50 value of 62.1 µg/mL. A bioassay-guided isolation of the active compounds from M. elengi leaf extract resulted in the isolation of active compounds, identified as a mixture of gallocatechin and epigallocatechin. This mixture of gallocatechin and epigallocatechin showed satisfactory anti-HIV-1 IN activity with an IC50 value of 35.0 µM. A flavanol glycoside, mearnsitrin was also isolated but was inactive at a concentration of 100 µM.