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Runner R T Majinda
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ABSTRACT: Due to their special structural features, extraction and isolation of saponins poses a serious challenge. Conventional methods have been explored as well as the recent, relatively greener, efficient, solvent-economic, time-saving, newer methods of extraction. Both traditional and recent methods of isolation are also discussed. Finally, examples are given involving both conventional and newer methods of extraction and isolation. Though in general it is difficult to use a single technique for isolation of saponins, recent literature work seems to point to the fact that high speed counter-current separation coupled to evaporative light scattering detector (ELSD) gives superior separation. The ELSD appears to have circumvented the long-standing problem of saponin detection as most of these do not have a chromophore, and hence making UV detection only nonspecific and at range 200-210 nm.
Methods in molecular biology (Clifton, N.J.) 01/2012; 864:415-26.
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ABSTRACT: In this study, 12 compounds, which include a new flavanone 5-methoxy mundulin (1), were isolated from the leaves, stem bark and twigs of Mundulea sericea (Willd.) A. Chev. (Fabaceae; Papilionoideae). The structures of the compounds were identified based on spectral data analyses. The constituents of M. sericea also showed antimicrobial activities (MIQ = 0.01-100 µg) against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans.
Natural product research 10/2011; 26(19):1817-23. · 1.01 Impact Factor
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ABSTRACT: The investigation of Tylosema esculentum (Morama) husks, cotyledons, and tuber yielded griffonilide 2, compound 1, griffonin 3, gallic acid 4, protocatechuic acid 5, β-sitosterol 6, behenic acid 7, oleic acid 8, sucrose 9, 2-O-ethyl-α-D-glucopyranoside 10, kaempferol 11 and kaempferol-3-O-β-D-glucopyranoside 12. The structures of the isolates were determined by NMR, HR-TOF EIMS, IR and UV-vis spectroscopy, and by comparison with literature data. The husk EtOAc and n-butanol extracts demonstrated >90% DPPH radical scavenging activity at concentrations of 25, 50 and 250 μg/mL. Furthermore the husk extracts showed higher total phenolic content (233 mg GAE/g). The extractives exhibited minimum inhibitory quantities of 50-100 μg or no activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. The tuber extracts were inactive against Caco-2 and Hela cell lines, while the husk extracts showed low activity against Caco-2 and Vero cell line with IC(50) values >400 μg/mL. The GC-MS analysis showed the beans and tuber non-polar (n-hexane) extracts major constituents as fatty acids.
Bioorganic & medicinal chemistry 09/2011; 19(17):5225-30. · 2.82 Impact Factor
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ABSTRACT: The objective of this study was to isolate and characterize the constituents of the local Morus nigra L. (Black mulberry), to compare its constituents with other studied Mulberries and to evaluate its anti-oxidative and anti-bacterial activities. The isolated compounds were identified by comparison of spectral data (UV, IR, MS and NMR) with literature values. The stem bark and wood of M. nigra yielded a stilbenoid oxyresveratrol 1, a 2-arylbenzofuran moracin M2, four isoprenylated flavonoids; cyclomorusin 3, morusin 4, kuwanon C5 and a derivative of kuwanon C6, two tritepenes; betulinic acid 7, α-amyrin acetate 8 and a steroidal saponin β-sitosterol-3-O-β-D-glucoside 9. The phenolic isolates showed moderate DPPH radical scavenging activity (EC 50 = 23-135 µgml -1) compared to ascorbic acid (EC 50 = 41 µgml -1) after 30 min. Compounds 1, 2 and 4 to 6 showed activities against Staphylococcus aureus, Bacillus subtilis, Micrococus flavus, Streptococcus faecalis, Salmonella abony, Pseudomonas aeruginosa.
African journal of pharmacy and pharmacology 07/2011; 5:751-754. · 0.84 Impact Factor
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ABSTRACT: Three new dihydro-beta-agarofuran polyesters, 1alpha,9beta-difuranoyloxy-2-oxodihydro-beta-agarofuran (1), 1alpha,9beta-difuranoyloxy-2-oxo-3-enedihydro-beta-agarofuran (2), and 1alpha,9beta-difuranoyloxydihydro-beta-agarofuran (3), have been isolated from the CHCl(3) extract of the root bark of Osyris lanceolata, together with two known pentacylic triterpenoids, 4 and 5. Compounds 1-5 did not scavenge the DPPH radical within 30 min of reaction time. All five compounds displayed antifungal activity against Candida albicans. Compounds 1, 3, 4, and 5 showed antibacterial activity against the Gram-positive Bacillus subtilis and Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa, with 4 and 5 being the most active. Compound 2 displayed weak antibacterial activity only against Escherichia coli.
Journal of Natural Products 06/2010; 73(6):1151-5. · 3.13 Impact Factor
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ABSTRACT: The root bark of Osyris lanceolata was screened for its antioxidant potential using three variations of the DPPH radical scavenging method viz a TLC-autographic assay, a semi-quantitative TLC assay, and a spectrophotometric assay. The total phenolic content was evaluated as gallic acid equivalents (GAE) using the Folin-Ciocalteu method. The powdered root bark was extracted sequentially with n-hexane, chloroform, methanol and 90% methanol/water. A separate supercritical fluid extraction (SFE) of the root bark was also carried out. The radical scavenging ability, as measured by IC50 values, was found to be 48.4 +/- 0.4 and 49.5 +/- 1.9 microg/mL for the 90% methanol/water and methanol extracts respectively, while those of the chloroform, n-hexane, and SFE extracts were found to be > 250 microg/mL. Under the same conditions, the values for the standards, ascorbic acid and gallic acid, were found to be 38.70 +/- 0.08 and 2.86 +/- 0.01 microg/mL respectively. The radical scavenging power of the five extracts correlated positively with the total phenolic content and was ranked in the following decreasing order: 90% methanol/water > methanol > chloroform > SFE > n-hexane with total phenolic contents of 290.2 +/- 3.3, 271.0 +/- 3.7, 74.4 +/- 0.8, 62.5 +/- 0.4 and 49.5 +/- 1.9 mg GAE/g of dry extract, respectively. The 90% methanol/water and methanol extracts showed several components with high antioxidant activity displaying fast kinetics in both TLC assays, while the chloroform, SFE, and n-hexane extracts exhibited slow kinetics antioxidant activity.
Natural product communications 01/2009; 4(1):89-94. · 1.24 Impact Factor
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ABSTRACT: Reversed-phase HPLC analyses of the methanol extract of the leaves of Erica arborea afforded a novel phenylpropanoid glucoside, named ericarborin, together with five flavonoids, dihydromyricetin 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-beta-D-glucopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside, apigenin 7-O-beta-D-glucopyranoside and apigenin 7-O-beta-D-(6-O-acetyl-glucopyranoside). While the structure of ericarborin was determined by extensive 1D and 2D NMR analyses, the structures of all known flavonoids were determined by direct comparison of their spectroscopic data with respective literature data. The antioxidant properties of these compounds were assessed by the DPPH assay. The chemotaxonomic significance of these phenolic compounds has been discussed.
Natural product research 02/2008; 22(16):1385-92. · 1.01 Impact Factor
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ABSTRACT: An efficient and enantioselective method for catalytic transfer hydrogenation of the C=C double bond of α-methylcinnamic acid with the aid of chiral organic acids as the hydrogen donors and palladium(II) chloride as the catalyst is reported. Enantiomeric excess was assayed using optical rotation measurements. The best stereoselectivity was achieved when L-(+)-tartaric acid was used as the hydrogen donor and acetonitrile as the solvent.
Bulletin of the Chemical Society of Ethiopia 11/2007; 21(3):457-460. · 0.39 Impact Factor
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ABSTRACT: The seeds and the pulp of Gardenia volkensii yielded one new iridiod, namely 4-(2N-gardenamide)n-butanoic acid, together with the known iridoids genipin and genipin gentiobioside, the pterocarpin medicarpin, coumarins, phenylpropanoids, benzenoids and triterpenes. The structures of these were determined on the basis of spectroscopic data and by comparison of obtained data with those from literature. The fruit extracts of this plant exhibited moderate radical scavenging activity against DPPH radical and moderate lethality against brine shrimps (Artemia salina).
Natural Product Research 03/2007; 21(2):121-5. · 1.01 Impact Factor
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ABSTRACT: The reversed-phase preparative HPLC analysis of the methanol extract of the rhizomes of Eremostachys glabra (Lamiaceae) led to the isolation of two furanolabdane diterpene glycosides, phlomisoside II, and beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl ester of phlomisoic acid (named eremostachiin), the latter being a novel natural product. The structure of the new compound has been elucidated unambiguously by HRMS and a series of 1D- and 2D-NMR spectroscopic techniques. The free radical scavenging activity of these compounds was assessed using the DPPH assay.
Natural Product Research 02/2006; 20(2):167-72. · 1.01 Impact Factor
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ABSTRACT: From the stem wood of Erythrina latissima, two isoflavones and a flavanone were isolated and characterized as 7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)isoflavone (erylatissin A), 7,3'-dihydroxy-6'',6''-dimethyl-4'',5''-dehydropyrano [2'',3'': 4',5']isoflavone (erylatissin B), (-)-7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)flavanone (erylatissin C), respectively, in addition to 10 known flavonoids. Structures of these compounds were determined on the basis of their spectroscopic data. These compounds showed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida mycoderma. The isolated compounds also exhibited weak radical scavenging properties towards DPPH radical.
Phytochemistry 02/2005; 66(1):99-104. · 3.35 Impact Factor
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ABSTRACT: Fourteen different erythrinaline alkaloids have been isolated from the flowers and pods of Erythrina lysistemon with four being reported for the first time in nature and five for the first time in this species and the rest having been re-isolated. The new compounds are (+)-11beta-hydroxyerysotramidine (1), (+)-11beta-methoxyerysotramidine (2), (+)-11beta-hydroxyerysotrine N-oxide (4) and (+)-11beta-hydroxyerysotrine (8). (+)-11alpha-Hydroxyerysotrine N-oxide (3), earlier misidentified as erythrartine N-oxide (beta-hydroxyerysotrine N-oxide 4), was also re-isolated along with four other alkaloids. Correct identification of compounds 4 and 8 was aided by the fact that the two sets of C-11 epimers 3, 4 and 8, 9 were both isolated in this study thus making it easier to identify and assign the individual epimers. (+)-Erythristemine (14) was found distributed in most of the plant parts investigated. Preliminary work on the crude chloroform/methanol (1:1) showed moderate toxicity to brine shrimp (LC50 23 ppm) and moderate (IC50 86 microg/ml) radical scavenging properties against stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging properties of the isolated compounds were assessed using TLC autographic and spectrophotometric assays whereupon only compounds 11 (1 microg; 90 microg/ml) and 12 (0.1 microg; 160 microg/ml) showed any notable activity. It appears the two compounds are slow reacting and do not reach steady state conditions within the standard half an hour time frame but only seemed to have reached steady state conditions after 4 h.
Phytochemistry 06/2004; 65(10):1397-404. · 3.35 Impact Factor
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ABSTRACT: Three new flavonoids-5,7,4'-trihydroxy-6-[1-hydroxy-2-methylbuten-2-yl]isoflavone (isogancaonin C), 7,2'-dihydroxy-4'-methoxyisoflav-3-ene (bolusanthin III), 6,6'-dihydroxy-4'-methoxy-2-arylbenzofuran (bolusanthin IV), in addition to eight known flavonoids; derrone, medicarpan, genistein, wighteone, lupiwighteone, gancaonin C, 7-hydroxy-4'-methoxyisoflavone and 7,3'-dihydroxy-4'-methoxyisoflavone were isolated from the root wood of Bolusanthus speciosus. The compounds showed strong antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida mycoderma. The isolated compounds also showed moderate to strong radical scavenging properties against DPPH radical with the highest activities shown by the 2-arylbenzofuran, the isoflav-3-ene and 7,3'-dihydroxy-4'-methoxyisoflavone in decreasing order.
Phytochemistry 05/2004; 65(7):875-80. · 3.35 Impact Factor
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ABSTRACT: A new isoflavanone namely 3,5,7,2',4'-pentahydroxy-8,3'-di(gamma,gamma-dimethylallyl)isoflavanone (bolusanthin II) and four new pterocarpans identified as 3-hydroxy-6',6'-dimethylpyrano[2',3':1,2] [6a R,11a R]-8,9-methylenedioxypterocarpan (bolucarpan A), 3-hydroxy-6',6'-dimethyl-4',5'-dihydropyrano[2',3':1,2][6a R,11a R]- 8,9-methylenedioxypterocarpan (bolucarpan B), 3-hydroxy-9-methoxy-6',6'-dimethylpyrano-[2',3':1,2][6a R,11a R]-pterocarpan (bolucarpan C) and 3-hydroxy-9-methoxy-6',6'-dimethyl-4',5'-dihydropyrano[2',3':1,2][6a R,11a R]-pterocarpan (bolucarpan D) and three known isoflavonoids were isolated from the methanolic extracts of the root bark, while eight known isoflavonoids were isolated from the stem bark of Bolusanthus speciosus. These compounds showed antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae and Candida mycoderma using the agar overlay technique.
Planta Medica 08/2002; 68(7):615-20. · 2.15 Impact Factor
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ABSTRACT: The genus Erythrina is very rich in secondary metabolites particularly of the flavonoids class. A literature survey of non-alkaloidal secondary metabolites from Erythrina showed the presence of flavanones, flavonols, chalcones, cinnamoylphenols, stilbenoids, isoflavones, isoflavans, isoflavanones, pterocarpans, isoflav-3-enes, 3-phenoxychromones, coumastans, 3-phenyl-coumarins, lignans, cinnamate esters, simple phenolics, triterpenes, sesquiterpenes, long-chain carboxylic acids, and long-chain alcohols. The documented bioactivities of some of the isolated metabolites range from antimicrobial, anti-inflammatory, inhibition of platelet aggregation, tyrosinase inhibition, phospholipase A2 (PLA2) inhibitors, cyclooxygenase inhibitors, antioxidant, inhibitors of NA+/H+ exchange system, phospholipase C inhibitors, behavioural depression, muscle relaxation, β-adrenergic inhibition, diuretic, anticancer, cytotoxic, DNA-repair properties, oestrogenic or proestrogenic activities, antitrypanosomal, antiplasmodial, and anti-HIV activities. The bioactivity profile represented the various classes fairly reasonably but it became apparent that a number of these isolates have not yet been tested for biological activity. A very close agreement between ethno-medical use of the various Erythrina extract preparations (Table 1) and the results of biological activity (Table 2) was found, with the reported activities of pure isolates strongly supporting the documented ethno-medical uses and reported pharmacological activity. The most common activity exhibited by extracts and pure isolates was mostly microbial related. It was also interesting to note that some compounds showed high efficacy against resistant organisms, a very important aspect, since most used drugs especially antibiotics tend to produce resistance to certain strains of organisms. The survey showed furthermore that certain structural features were essential for certain activities and also that compounds that were found active were usually effective against not just one but several disease functions. One cannot help but surmise that more activities are yet to be reported for these same isolates. The challenge remains for researchers in the various pertinent disciplines to carry out more work on these to fill in the knowledge gaps that still exist.
Studies in Natural Products Chemistry. 32:821-853.
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ABSTRACT: The n-hexane and ethyl acetate extracts of the aerial parts of Vahlia capensis yielded the coumarins umbelliferone, scopoletin and scoparone, and the terpenoids sitosterol, cycloartenol, 24-methylenecycloartanol, cycloart-23-en-3β,25-diol, glutinol and a seco ring-A triterpene acid, 3,4-seco-olean-4,(23),18-dien-3-oic acid.
Phytochemistry.
