Crude Dichloromethane Research Articles

HPLC–NMR and HPLC–MS investigation of antimicrobial constituents in Cystophora monilifera and Cystophora subfarcinata

The crude dichloromethane extracts of the marine brown algae Cystophora monilifera and Cystophora subfarcinata were subjected to phytochemical profiling. This enabled the structures of both new and known phloroglucinols to be dereplicated and proposed using HPLC–NMR and HPLC–MS. Subsequent isolation confirmed the presence of four new and eight previously reported compounds. Five of the isolated phloroglucinols displayed selective antimicrobial activity.

Bioactivity and chemical characterisation of Lophostemon suaveolens – an endemic Australian Aboriginal traditional medicinal plant

Lophostemon suaveolens is a relatively unexplored endemic medicinal plant of Australia. Extracts of fresh leaves of L. suaveolens obtained from sequential extraction with n-hexane and dichloromethane exhibited antibacterial activity in the disc diffusion and MTT microdilution assays against Streptococcus pyogenes and methicillin sensitive and resistant strains of Staphylococcus aureus (minimum bactericidal concentration < 63 μg/mL). The dichloromethane extract and chromatographic fractions therein inhibited nitric oxide in RAW264.7 murine macrophages (IC50 3.7–11.6 μg/mL) and also PGE2 in 3T3 murine fibroblasts (IC50 2.8–19.7 μg/mL). The crude n-hexane, dichloromethane and water extracts of the leaves and chromatographic fractions from the dichloromethane extract also showed modest antioxidant activity in the ORAC assay. GC–MS analysis of the n-hexane fraction showed the presence of the antibacterial compounds aromadendrene, spathulenol, β-caryophyllene, α-humulene and α-pinene and the anti-inflammatory compounds β-caryophyllene and spathulenol. Fractionation of the dichloromethane extract led to the isolation of eucalyptin and the known anti-inflammatory compound betulinic acid.

Antioxidant, hemolytic, antimicrobial, and cytotoxic activities of the tropical Atlantic marine zoanthid Palythoa caribaeorum.

Marine invertebrates are capable of synthesizing bioactive compounds, which may be beneficial to human health. The aim of this study was to evaluate the antioxidant, hemolytic, antimicrobial and cytotoxic activities of crude extract (70% EtOH), and dichloromethane (DCM), ethyl acetate (EtOAc), and aqueous (Aq) fractions of the marine zoanthid Palythoa caribaeorum. The phenolic compound contents of the crude extract, DCM, EtOAc and Aq fractions were 12.33, 18.17, 10.53, and 3.18 mg GAE per gram, respectively. DPPH radical scavenging activity showed slight variation. IC50 of crude extract, DCM, EtOAc and Aq fractions were 11.13, 11.25, 11.74, and 11.28 µg mL(-1), respectively. Among the sample, ferrous ion chelating was the highest in crude extract (IC50 302.90 µg mL(-1)), followed by EtOAc, Aq, and DCM fractions with 457.77, 547.91, and 641.82 µg mL(-1), respectively. Ferric-reducing antioxidant power showed optical density at about 0.5. The samples tested exhibited low hemolytic activity under 10% up to a concentration of 50 μg mL(-1). No antimicrobial activity was observed against any of the tested bacterial strains. For the cytotoxic activity, LC50 of DCM, crude extract, EtOAc, and Aq were 52.10, 83.06, 86.34, and 117.45 μg mL(-1), showing high toxicity.

Assessing chemical constituents of Mimosa caesalpiniifolia stem bark: possible bioactive components accountable for the cytotoxic effect of M. caesalpiniifolia on human tumour cell lines.

Mimosa caesalpiniifolia is a native plant of the Brazilian northeast, and few studies have investigated its chemical composition and biological significance. This work describes the identification of the first chemical constituents in the ethanolic extract and fractions of M. caesalpiniifolia stem bark based on NMR, GC-qMS and HRMS analyses, as well as an assessment of their cytotoxic activity. GC-qMS analysis showed fatty acid derivatives, triterpenes and steroid substances and confirmed the identity of the chemical compounds isolated from the hexane fraction. Metabolite biodiversity in M. caesalpiniifolia stem bark revealed the differentiated accumulation of pentacyclic triterpenic acids, with a high content of betulinic acid and minor amounts of 3-oxo and 3β-acetoxy derivatives. Bioactive analysis based on total phenolic and flavonoid content showed a high amount of these compounds in the ethanolic extract, and ESI-(−)-LTQ-Orbitrap-MS identified caffeoyl hexose at high intensity, as well as the presence of phenolic acids and flavonoids. Furthermore, the evaluation of the ethanolic extract and fractions, including betulinic acid, against colon (HCT-116), ovarian (OVCAR-8) and glioblastoma (SF-295) tumour cell lines showed that the crude extract, hexane and dichloromethane fractions possessed moderate to high inhibitory activity, which may be related to the abundance of betulinic acid. The phytochemical and biological study of M. caesalpiniifolia stem bark thus revealed a new alternative source of antitumour compounds, possibly made effective by the presence of betulinic acid and by chemical co-synergism with other compounds.

Stabilization of Groundnut Oil with Natural Antioxidants Extracted from Bauhinia Species and Piliostigma reticulatum

The total phenol and antioxidant activity of the crude extract, dichloromethane, ethylacetate and butanol fractions of the leaves of Bauhinia species and Piliostigma reticulatum plants were determined and EC50 value calculated. The extract with highest antioxidant activity was used in the stabilization study of freshly extracted groundnut oil samples. The results revealed that ethylacetate fraction of P. reticulatum had the highest total phenolic content (106.50 ± 2.26 mg gallic acid equivalent per gram extract) and the lowest EC50 value (8.29 μg/mL). The stabilization study revealed that the plant extract-protected groundnut oil recorded the least values for lipid hydroperoxide, thiobarbituric acid reactive substances and p-anisidine value and the least reduction in total tocopherol. This showed that the plant extract had sparring role on tocopherol. It can be concluded that ethylacetate fraction of P. reticulatum was a better antioxidant than butylated hydroxyanisole and could be used as an antioxidant in vegetable oil. Practical Applications The etiology of some diseases such as cancer has been linked to synthetic antioxidant used in the preservation of vegetable oil. Hence, the replacement of these synthetic compounds with extracts obtained from medicinal plants such as Bauhinia species and P. reticulatum will be a step in the right direction. The ethylacetate extract from P. reticulatum showed a great potential as an antioxidant against lipid oxidation. The extract of this plant can be used as a possible replacement for synthetic antioxidants for the preservation of the nutritional quality of vegetable oil.

Chemical profiling (HPLC-NMR & HPLC-MS), isolation, and identification of bioactive meroditerpenoids from the southern Australian marine brown alga Sargassum paradoxum.

A phytochemical investigation of a southern Australian marine brown alga, Sargassum paradoxum, resulted in the isolation and identification of four new (5, 9, 10, and 15) and nine previously reported (1, 2, 6–8, and 11–14) bioactive meroditerpenoids. HPLC-NMR and HPLC-MS were central to the identification of a new unstable compound, sargahydroquinal (9), and pivotal in the deconvolution of eight (1, 2, 5–7, and 10–12) other meroditerpenoids. In particular, the complete characterization and identification of the two main constituents (1 and 2) in the crude dichloromethane extract was achieved using stop-flow HPLC-NMR and HPLC-MS. This study resulted in the first acquisition of gHMBCAD NMR spectra in the stop-flow HPLC-NMR mode for a system solely equipped with a 60 μL HPLC-NMR flow cell without the use of a cold probe, microcoil, or any pre-concentration.

Synergic evaluation of associations of crude Pterodon pubescens Benth dichloromethane extract and Varronia spp essential oil in antinociceptive experimental models

Synergic evaluation of associations of crude Pterodon pubescens Benth dichloromethane extract and Varronia spp essential oil in antinociceptive experimental models

Antibacterial effect of crude dichloromethane extract and fractions obtained from Vexibia alopecuroides L. Jakovl

Antibacterial effect of crude dichloromethane extract and fractions obtained from Vexibia alopecuroides L. Jakovl

Oil absorbency of cellulose/butylmethacrylate graft polymer fibers

Cotton pulp cellulose and butyl methacrylate were used as the main raw materials to synthesize cellulose/butylmethacrylate graft polymer (Cell-g-PBMA) via homogeneous ATRP method, after which the graft polymer was dissolved in N,N-dimethylacetamide to prepare a spinning solution, and the novel oil-absorbent Cell-g-PBMA graft polymer fibers were spun by wet-spinning method. The morphology of the polymer fibers before and after oil absorption was analyzed using a high-powered microscope and scanning electron microscope and the saturated oil absorption rate as well as buoyancy recovery of the fiber products were also studied. The results showed that Cell-g-PBMA polymer fibers had a rough surface and exhibited a void network structure that was specific to oil-absorbent materials. The saturated absorption rates of the Cell-g-PBMA polymer fibers for crude oil, vegetable oil, dichloromethane and diesel were 96.5, 78.7, 38.4, and 27.2 g/g, respectively, which were about 3–6 times that of a commercial polypropylene sorbent. The Cell-g-PBMA fibers also displayed excellent oil/water selectivity and high buoyancy recovery in the clean-up of oil over water. Its excellent oil absorbency demonstrated oil absorbent characteristics of both traditional oil-absorbing materials and synthetic oil-absorbing resins, rendering it an excellent fibrous oil-absorbent material.

Anti-invasive Activity against Cancer Cells of Phytochemicals in Red Jasmine Rice (Oryza sativa L.)

Red rice contains pharmacological substances including phenolics, oryzanol, tocotrienol and tocopherol. Recently, red rice extract has been employed as a source of antioxidants for inhibition of tumor growth. This study was carried out to evaluate the anti-invasion effects of red rice extract fractions on cancer cells. It was found that at 100 μg/ml of crude ethanolic extract (CEE), hexane fraction (Hex) and dichloromethane fraction (DCM) could reduce HT1080 and MDA-MB-231 cancer cell invasion. Hex and DCM revealed higher potency levels than CEE, whereas an ethyl acetate fraction (EtOAc) had no effect. Gelatin zymography revealed that Hex decreased the secretion and activity of matrix metalloproteinase-2 and -9 (MMP-2 and-9). In contrast, the DCM fraction exhibited slightly effect on MMPs secretion and had no effect on MMPs activity. Collagenase activity was significantly inhibited by the Hex and DCM fractions. High amounts of γ-oryzanol and γ-tocotrienol were found in the Hex and DCM fractions and demonstrated an anti-invasion property. On the other hand, proanthocyanidin was detected only in the CEE fraction and reduced MDA-MB-231 cells invasion property. These observations suggest that proanthocyanidin, γ-oryzanol and γ-tocotrienol in the red rice fractions might be responsible for the anti invasion activity. The red rice extract may have a potential to serve as a food-derived chemotherapeutic agent for cancer patients.

Antiplasmodial, acetylcholinesterase and alpha-glucosidase inhibitory and cytotoxicity properties of Buddleja saligna

The crude ethanolic extract, hexane, dichloromethane, ethyl acetate and aqueous fractions of Buddleja saligna leaves were investigated for antiplasmodial, alpha-glucosidase and acetylcholinesterase inhibitory and cytotoxicity properties. Although the crude extract displayed some level of activity, the hexane fraction demonstrated the best antiplasmodial (IC50=8.5μg/ml), alpha-glucosidase inhibitory (IC50=260μg/ml) and anticholinesterase (IC50=124.8μg/ml) activities. The safety index values of the hexane fraction [antiplasmodial (0.2), alpha-glucosidase inhibition (0.007) and anticholinesterase (0.01)] revealed that the fraction is cytotoxic. These findings highlight the importance of reporting the SI values of biologically active samples together with their biological activities. It remains to be determined whether the toxicity observed is caused by the compounds responsible for the biological activities investigated or not.

Purification and identification of metabolites produced by Bacillus cereus and B. subtilis active against Meloidogyne exigua, and their in silico interaction with a putative phosphoribosyltransferase from M. incognita.

To contribute to the development of products to control Meloidogyne exigua, the bacteria Bacillus cereus and B. subtilis were cultivated in liquid medium to produce metabolites active against this plant-parasitic nematode. Fractionation of the crude dichloromethane extracts obtained from the cultures afforded uracil, 9H-purine and dihydrouracil. All compounds were active against M. exigua, the latter being the most efficient. This substance presented a LC50 of 204 µg/mL against the nematode, while a LC50 of 260 µg/mL was observed for the commercial nematicide carbofuran. A search for protein-ligand complexes in which the ligands were structurally similar to dihydrouracil resulted in the selection of phosphoribosyltransferases, the sequences of which were used in an in silico search in the genome of M. incognita for a similar sequence of amino acids. The resulting sequence was modelled and dihydrouracil and 9H-purine were inserted in the active site of this putative phosphoribosyltransferase resulting in protein-ligand complexes that underwent molecular dynamics simulations. Calculation of the binding free-energies of these complexes revealed that the dissociation constant of dihydrouracil and 9H-purine to this protein is around 8.3 x 10-7 and 1.6 x 10-6 M, respectively. Consequently, these substances and the putative phosphoribosyltransferase are promising for the development of new products to control M. exigua.

Anthelmintic activity in vitro and in vivo of Baccharis trimera (Less) DC against immature and adult worms of Schistosoma mansoni

Although its efficiency against all Schistosoma species, praziquantel (PZQ) shows low efficacy against schistosomula and juvenile stages. The potential for development of resistance to PZQ has justified the search for new alternative chemotherapies. In this scenario, studies to new formulations, more comprehensive and without adverse effects, are being conducted. One viable and promising treatment is the study of medicinal plants as a new approach to the experimental treatment for Schistosomiasis. Amongst all the variety of the medicinal species studied, we can highlight Baccharis trimera (Less) DC, known as “Carqueja-amarga”. This paper not only describes the effect of crude dichloromethane extract (DE) and aqueous fraction (AF) obtained from B. trimera, in vitro but also is the first one that investigates the in vivo efficacy of B. trimera against schistosomula, juvenile and adult worms of Schistosoma mansoni BH strain. In the experiment, mice were treated with DE, AF and PZQ (40 and 200mg/kg) over the period of larval development (3 and 30 post-infection; pi), and adult worms (60days post-infection; pi). The in vitro results show that the DE and AF effects are dose-dependents, being the 130μg/mL the most effective one in a shorter period of incubation. The exposure of the in vitro samples over adult parasites were able to inhibit 100% of the oviposition in females. Likewise caused the mortality of the parasites with morphological alterations on the tegument, on the suckers, oral and acetabulum, in both males and females after 6–72h of exposure. Additionally, the in vivo treatments against juvenile and adult infection were more effective compared to the control group untreated. Administrations of AF and DE in day 30pi (juvenile worms) show female worm total burden reductions of 75% and 68% respectively. At the same period of infection reductions of respectively 98% and 97% egg/g in the faeces were seen. In relation to the different egg developmental stages (oogram), the results showed significant reductions, due to the reduction in the number of worms, especially the females. In conclusion, B. trimera exhibits major schistosomicidal effects in vivo against immature and adult worms of S. mansoni, opening up perspectives for future researches on substance or compound isolation and the elucidation of its mechanisms of action.

Vacuum Liquid Chromatography of Cystoseira usneoides for purification of antioxidant compounds.

Event Abstract Back to Event Vacuum Liquid Chromatography of Cystoseira usneoides for purification of antioxidant compounds. Sylvie Santos1, Joana Silva2, Susete Pinteus2, André Horta2, Celso Alves2 and Rui Pedrosa2* 1 Berufskolleg für Biotechnik in Hohenheim, Landwirtschaftliche Schule Stuttgart Hohenheim, Germany 2 School of Tourism and Maritime Technology - IPL, GIRM, Portugal Cystoseira usneoides is a brown algae commonly found in the Portuguese coast. A previous study has reported high antioxidant activity of its extract, however, few works have been made in order to isolate and identify the molecules responsible for the antioxidant activity. In this work, a vacuum liquid chromatography (VLC) was performed to Cystoseira usneoides dichloromethane extract using silica gel with the following solvents system: 100% cyclohexane followed by a mixture of 3:1; 1:1; 1:3 of cyclohexane and ethyl acetate and 100 % ethyl acetate. The five fractions were concentrated in a rotary evaporator and dissolved in DMSO at 100mg/ml. The antioxidant potential of all fractions was evaluated by both, the quantification of the total phenolic content (TPC) and by the evaluation of the DPPH radical scavenging activity. Comparatively to the initial values of DPPH radical scavenging activity (IC50= 81.8 µg/ml (54.74-122.2)) and the total phenolic content (86.28 ± 0.002 mg of gallic acid eq./g of extract) of the crude dichloromethane extract, all the fractions obtained by VLC in a silica gel column reported much less antioxidant activity. The most active fractions scavenging the DPPH radical were F3, F4 and F5 which presented and IC50 of 1314 (1209-1429), 2084 (1624-2674) and 1414 (1199-1668) µg/ml, respectively. F5 fraction presented the highest phenolic content of 20.85 mg of gallic acid equivalents/g of extract. The results suggest that the compounds we are trying to isolate have strong affinity with the stationary phase, and therefore, weren’t eluted with the solvents, even with the increasing polarity along the chromatography. Even though VLC, with a silica gel column, have already revealed to be efficient for separation of compounds extracted with dichloromethane, as regards to antioxidant compounds, these continue to be a great challenge. Keywords: VLC, Brown algae, Total phenolic content, DPPH radical scavenging activity, Bioactive marine natural compounds Conference: IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014. Presentation Type: Poster Presentation Topic: BLUE BIOTECH Citation: Santos S, Silva J, Pinteus S, Horta A, Alves C and Pedrosa R (2014). Vacuum Liquid Chromatography of Cystoseira usneoides for purification of antioxidant compounds.. Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2014. doi: 10.3389/conf.fmars.2014.02.00051 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 May 2014; Published Online: 18 Jul 2014. * Correspondence: Prof. Rui Pedrosa, School of Tourism and Maritime Technology - IPL, GIRM, Peniche, 2520–641, Portugal, rpedrosa@ipleiria.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sylvie Santos Joana Silva Susete Pinteus André Horta Celso Alves Rui Pedrosa Google Sylvie Santos Joana Silva Susete Pinteus André Horta Celso Alves Rui Pedrosa Google Scholar Sylvie Santos Joana Silva Susete Pinteus André Horta Celso Alves Rui Pedrosa PubMed Sylvie Santos Joana Silva Susete Pinteus André Horta Celso Alves Rui Pedrosa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

In vivo antiprostate tumor potential of Vernonia guineensis Benth. (Asteraceae) tuber extract (VGDE) and the cytotoxicity of its major compound pentaisovaleryl sucrose

Vernonia guineensis Benth. (Asteraceae) root decoction is used in folk medicine in Cameroon to treat some ailments including prostate cancer. The aim of this study was to validate the claimed antiprostate cancer activity of Vernonia guineensis Benth. in vivo and to investigate the cytotoxicity of a pentaisovaleryl sucrose isolated from Vernonia guineensis on some cancer cell lines. A crude dichloromethane extract of Vernonia guineensis (VGDE) was used for this study. For in vivo antiprostate cancer efficacy, nude mice (n=16) were injected subcutaneously with prostate cancer PC-3 cells. Upon the formation of the xenograft tumors, the mice were divided into two equal groups with approximately the same mean tumor volume per group. One group was treated with VGDE orally (500 mg/kg) and the other with a vehicle control for 30 days. Body weight and tumor volumes were measured 2× a week and on the 33rd day, the mice were euthanized and tumors harvested and weighed. For the cytotoxicity study, the WST-1 assay was used to determine the activity of pentaisovaleryl sucrose previously isolated from VGDE. The cancer cell lines used in the cytotoxicity study included breast, colon, leukemia, lung, melanoma, ovarian and prostate. Prostate cancer (PC-3) xenograft tumors treated with VGDE showed a significant decrease in tumor size (P=0.0295) compared to control. Pentaisovaleryl sucrose also demonstrated cytotoxicity against various cancer cell lines with IC₅₀ values as follows: MDA-MD-231-6.66µM; MCF-7-7.50 µM; HCT116-14.12 µM; A549-5.76 µM; HL60-6.43 µM; A375-8.64 µM; OVCAR3-9.53 µM; Capan1-7.13 µM; Mia-Paca 6.47 µM. VGDE does possess in vivo activity against prostate tumor and has potential for development into a natural product for the treatment of prostate cancer. This study thus provides preliminary validation for the folk use of Vernonia guineensis against prostate conditions. Further in vivo studies are however required to confirm these results and to understand the mechanism of action of VGDE and the in vivo efficacy of pentaisovaleryl sucrose.

Chemical Constituents of Cinnamomum rupestre and Cinnamomum nanophyllum

Cinnamomum rupestre Kosterm. (Lauraceae) is an endemic species in the Philippines originally discovered in Palawan [1], while Cinnamomum nanophyllum Kosterm. is a widespread endemic species in the country. In Cebu, the local people collect and prepare the leaves and the bark as a decoction for relief of stomach and abdominal ailments. There are no reported chemical and biological studies on C. rupestre and C. nanophyllum. These are two of the 21 species of Cinnamomum found in the Philippines, of which 16 are known to be endemic [1]. This study was conducted as part of our research on the chemical constituents of Cinnamomum species found in the Philippines. We earlier reported the isolation of eugenol and safrole from the bark, polyprenol from the leaves, and trilinolein from the roots of Cinnamomum cebuense [2]. Silica gel chromatography of the dichloromethane (DCM) extract of the bark of C. rupestre afforded 4 -hydroxy5,7,3 -trimethoxyflavan-3-ol (1), 4-hydroxy-3-methoxycinnamaldehyde (2), and 4-allyl-2-methoxyphenol or eugenol (3), while the leaves yielded -sitosterol (4). The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by comparison of its 13C NMR data with those reported in the literature for 4 -hydroxy-5,7,3 -trimethoxyflavan-3-ol (1) [3]. The structures of 4-hydroxy-3-methoxycinnamaldehyde (2) [4], 4-allyl-2-methoxyphenol or eugenol (3) [5], and -sitosterol (4) [6] were confirmed by comparison of their 13C NMR data with those reported in the literature. The DCM extract of the bark of C. nanophyllum afforded 1, 2, 4, and trilinolein (5), while the leaves yielded 4. The structure of trilinolein (5) [7] was confirmed by comparison of its 13C NMR data with those reported in the literature. To the best of our knowledge, this is the first report on the chemical constituents of C. rupestre and C. nanophyllum. The bark and leaves of Cinnamomum rupestre and Cinnamomum nanophyllum were collected from Hagnaya, Carmen, Cebu, Philippines in June 2010. Voucher specimens of Cinnamomum rupestre and Cinnamomum nanophyllum were authenticated by one of the authors (EMGA) and deposited in the De La Salle University-Manila Herbarium (DLSU-3101 and DLSU-3102, respectively). The air-dried bark and leaves of C. rupestre were chopped into small pieces and then air dried. The air-dried bark (371.8 g) and leaves (89.1 g) were soaked in DCM for 3 days and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts of bark (16.6 g) and leaves (7.0 g), which were fractionated by silica gel chromatography using increasing proportions of acetone in DCM (10% increment by volume) as eluents. The DCM fraction from the bark was rechromatographed in petroleum ether (7 ) to afford 3 (28 mg). The 30% acetone in DCM fraction was rechromatographed with 12.5% ethyl acetate in petroleum ether as eluent to afford 2 (18 mg). The 40% acetone in DCM fraction was rechromatographed (5 ) in DCM, then (8 ) in diethyl ether–acetonitrile–DCM (0.5:0.5:9) to afford 1 (12 mg). The DCM fraction from the leaves was rechromatographed (3 ) in 5% ethyl acetate in petroleum ether to afford 4 (10 mg). The air-dried bark and leaves of C. nanophyllum were chopped into small pieces and then air dried. The air-dried bark (493.5 g) and leaves (49.5 g) were soaked in DCM for three days and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts of bark (8.0 g) and leaves (9.5 g), which were fractionated by silica gel chromatography using increasing proportions of acetone in DCM (10% increment by volume) as eluents. The crude DCM extract of the bark of C. nanophyllum was chromatographed in increasing proportions of acetone in DCM at 10% increment as eluents. The 10%

Antiplasmodial activity of some plants used by Zulu traditional healers and some of triterpenes isolated from the plants

Mimusops caffra E. Mey. ex A.DC., Mimusops obtusifolia, Lam (both members of Sapotaceae family) and Hpoxis colchicifolia, Bak are used by traditional healers in Zululand to manage malaria. We have investigated the anti-plasmodial activity of the crude extracts and isolated pure compounds of these plants. The crude dichloromethane extracts of the plants showed activity against the chloroquine sensitive (CQS) strain of Plasmodium falciparum (D10). The crude plants extracts exhibited activity with IC50 values raging from 2.14 µg/ml to 32.5 µg/ml. The pentacyclic triterpenoids (PTCs) isolated and characterized (through IR, NMR, MS spectral data) from the leaves and stem bark of M. caffra and M. obtusifolia include taraxerol (I), Sawamilletin (II), and ursolic acid (III). Ursolic acid was found to have anti-plasmodial activity (IC50, 6.8 µg/ml). The results validate the use of these plants in folk medicine.

HPLC-NMR Chemical Profiling and Dereplication Studies of the Marine Brown Alga, Cystophora torulosa

A chemical profiling/dereplication exercise, involving the use of HPLC-NMR and mass spectrometry in combination with the MarinLit database, was conducted on the crude dichloromethane extract of the southern Australian marine brown alga Cystophora torulosa. This strategy was successful in identifying a total of nine secondary metabolites representing two principle structure classes, including seven resorcinol (1–7) and two polyene derivatives (8 and 9). Validation of this on-line dereplication strategy was supported by the isolation and complete 2D NMR assignment of the major secondary metabolite (1). This methodology was concluded to be suitable for the rapid on-line identification of the resorcinol and polyene structure classes that are frequently encountered in the genus Cystophora.

Isolation of Ingenol-Type Diterpenoids from Euphorbia kansui by Offline Coupling of HPLC-ESI-MSn and HSCCC

A method based on an offline coupling of high-performance liquid chromatography/electrospray ionization multi-stage mass spectrometry (HPLC-ESI-MSn) and high-speed counter-current chromatography (HSCCC), was established for targeted separation and purification of skin-irritative and structurally similar ingenol-type diterpenoids in Euphorbia kansui. The crude dichloromethane extract of Euphorbia kansui after an initial clean-up step on silica gel and targeted fractionation according to HPLC-ESI-MSn, was separated by HSCCC. As a result, 3-O-(2′E,4′Z-decadienoyl)-20-O-acetylingenol and 3-O-(2′E,4′E-decadienoyl)-20-O-acetylingenol as well as a pair of geometrical isomers, 5-O-(2′E,4′Z-decadienoyl)-20-O-acetylingenol and 5-O-(2′E,4′E-decadienoyl)-20-O-acetylingenol, were successfully separated and purified. The established method is rapid and efficient without irritation to operators, providing an extensible and feasible way for the separation and purification of other toxic and skin-irritative compounds.

Chemical and biological investigations of the leaves of Gynura procumbens

The crude n-hexane (HX), dichloromethane (DCM), methanol (ME) and ethyl acetate (EA) extracts of the leaves of Gynura procumbens were subjected to antioxidant, antibacterial and antifungal activities and cytotoxicity against brine shrimp nauplii. The DCM and EA extracts exhibited mild antimicrobial activities, whereas, HX and ME extracts did not show any sort of sensitivity. On the other hand, the brine shrimp lethality with LC50 values was 70.71, 0.78, 4.42 and 59.46 µg/mL for HX, DCM, ME and EA extracts, respectively indicates the presence of potent bioactive compounds. At the same time, among the four crude extracts, only ME and HX extracts showed potential antioxidant activity with IC50 values of 20.35 and 48.0µg/mL. A pure compound was isolated from HX extract and the structure of the compound was elucidated as stigmasterol by means of 1H NMR spectroscopy.