Rumen fermentation and microbial population in lactating dairy cows receiving diets containing oilseeds rich in C-18 fatty acids.

Sixteen Holstein rumen-cannulated primiparous milking dairy cows were fed a control diet (CN) based on maize silage and soyabean meal during a 4-week period before the start of a 21-d experiment with oilseeds containing high concentration of linoleic acid (Linola™) or linolenic acid (NuLin™). Thereafter, four cows received ad libitum one of each of four dietary treatments comprising of CN, Linola (LN), NuLin (NL) and LN/NL (50/50 % combination). Each LN, NL and LN/NL treatment contained 6 % oil of DM. Rumen digesta samples were collected on days 6, 11, 16 and 21 and milk samples on days 13, 15 and 17. There were no effects (P>0.05) of the oilseeds on pH and concentrations of NH3-N and total volatile fatty acids, while the acetate:propionate ratio was decreased (P< 0.05). The oilseeds also decreased (P< 0.05) protozoa and increased (P< 0.1) total cellulolytic bacteria in rumen fluid, especially when containing high dietary linoleic acid (P< 0.05). The milk protein concentration was increased (P< 0.1) by the dietary linoleic acid, which produced most beneficial results. It was concluded that supplements of linoleic acid in diets of ruminants might contribute to better digestion of dietary fibre and increased quality of milk.

Supplementation with whole cottonseed causes long-term reduction of methane emissions from lactating dairy cows offered a forage and cereal grain diet.

The objective of our work was to supplement a forage and cereal diet of lactating dairy cows with whole cottonseed (WCS) for 12 wk and to determine whether the expected reduction in CH(4) would persist. A secondary objective was to determine the effect of supplementing the diet with WCS on milk yield and rumen function over the 12-wk feeding period. Fifty lactating cows were randomly allocated to 1 of 2 diets (control or WCS). The 2 separate groups were each offered, on average, 4.2 kg of DM/cow per day of alfalfa hay (a.m.) and 6.6 kg of DM/cow per day of ryegrass silage (p.m.) on the ground in bare paddocks each day for 12 wk. Cows in each group were also individually offered dietary supplements for 12 wk in a feed trough at milking times of 5.4 kg of DM/cow per day of cracked wheat grain and 0.5 kg of DM/cow per day of cottonseed meal (control) or 2.8 kg of DM/cow per day of cracked wheat grain and 2.61 kg of DM/cow per day of WCS. The 2 diets were formulated to be similar in their concentrations of CP and ME, but the WCS diet was designed to have a higher fat concentration. Samples of rumen fluid were collected per fistula from the rumen approximately 4 h after grain feeding in the morning. Samples were taken from 8 cows (4 cows/diet) on 2 consecutive days in wk 2 of the covariate and wk 3, 6, 10, and 12 of treatment and analyzed for volatile fatty acids, ammonia-N, methanogens, and protozoa. The reduction in CH(4) emissions (g/d) because of WCS supplementation increased from 13% in wk 3 to 23% in wk 12 of treatment. Similarly, the reduction in CH(4) emissions (g/kg of DMI) increased from 5.1% in wk 3 to 14.5% in wk 12 of treatment. It was calculated that the average reduction in CH(4) emissions over the 12-wk period was 2.9% less CH(4) per 1% added fat, increasing from 1.5% in wk 3 to 4.4% less CH(4) in wk 12. There was no effect of WCS supplementation on rumen ammonia-N, rumen volatile fatty acids, rumen methanogens, and rumen protozoa. On average over the 12-wk period, supplementation with WCS decreased the yield of milk (10%), fat (11%), protein (14%), lactose (11%), and fat plus protein (12%) and BW gain (31%). The WCS supplementation had no effect on milk fat concentration but resulted in a decrease in concentration of protein (5%) and lactose (11%). The major finding from this study is that addition of WCS to the diet of lactating dairy cows resulted in a persistent reduction in CH(4) emissions (g of CH(4)/kg of DMI) over a 12-wk period and that these reductions in CH(4) are consistent with previous work that has studied the addition of oilseeds to ruminant diets.

Homocysteine, folates, and the eye.

Plasma homocysteine has been identified as a risk factor for arterial disease, retinal artery and vein occlusions, and other common eye diseases. The value of treating an elevated plasma homocysteine with folic acid for preventing further vascular disease has not been proven. Although secondary prevention of coronary artery disease using this approach has been unsuccessful, trials on primary prevention of stroke and loss of cognitive function with folic acid supplementation appear to be successful. Further trial data are awaited. In patients with premature retinovascular disease, the measurement of plasma homocysteine is suggested and reduction of elevated homocysteine with folic acid for secondary prevention of retinal arterial and venous occlusion. Meanwhile, the debate on fortification of flour for primary prevention of neural tube defects, which has already taken place in North America, continues in European countries. Such fortification could have an impact on primary and secondary prevention of vascular disease.

Evaluation of selected Sudanese medicinal plants for their in vitro activity against hemoflagellates, selected bacteria, HIV-1-RT and tyrosine kinase inhibitory, and for cytotoxicity.

Ethnobotanical investigations led to the selection of 19 plant species, used traditionally in Sudan against malaria and other similar tropical diseases, for further studies. Pamianthe peruviana (Amaryllidaceae) exhibited significant activity against a chloroquine-resistant Plasmodium falciparum strain (K1) and a chloroquine-sensitive strain (NF54) with IC(50) values of 0.6 and 1.1 microg/ml, respectively. Additionally, P. peruviana showed considerable activities against Trypanosoma brucei rhodesiense (IC(50) 1.5 microg/ml) and T. cruzi (IC(50) 11.8 microg/ml). The antiplasmodial activity of the different extracts of Salvadora persica (Salvadoraceae) against P. falciparum NF54 strain were found to be 0.6 microg/ml (stems) and 0.7 microg/ml (leaves). Extracts of different parts of Combretum hartmannianum (Combretaceae) possessed significant activity against the chloroquine-sensitive P. falciparum strain (NF54) with IC(50) values of 0.2 microg/ml (bark), 0.4 microg/ml (stem) and 4.3 microg/ml (leaves). Most interestingly, the extracts of the leaves of C. hartmannianum totally inhibited the enzyme HIV-1 reverse transcriptase (HIV-1 RT) at a concentration of 66 microg/ml. A comparably strong activity against p56(lck) tyrosine kinase was also seen for this extract.

Assessment of antimycobacterial activity of a series of mainly marine derived natural products.

A series of mainly marine derived natural products were tested for their activities against Mycobacterium tuberculosis and M. avium. Of the thirty-nine compounds tested fifteen demonstrated minimum inhibition concentrations (MICs) of 32 micrograms/ml or less, and eleven had MICs of 16 micrograms/ml or less. The most active compound found in this study was the sponge derived metabolite axisonitrile-3 (MIC 2 micrograms/ml).

HIV reverse transcriptase inhibitors of natural origin.

Inhibitors of HIV reverse transcriptase (RT) are important drugs for the treatment of acquired immuno-deficiency syndrome (AIDS). One approach to identify novel inhibitors of HIV-1-RT is the screening of natural compounds. Many natural products have been shown to be active as RT inhibitors. These compounds belong to a wide range of different structural classes, e.g., coumarins, flavonoids, tannins, alkaloids, lignans, terpenes, naphtho- and anthraquinones, and polysaccharides. The life forms from which the bioactive compounds were isolated are as equally diverse and comprise terrestrial and marine plants, micro-organisms, and marine animals. From the most extensive screening effort, carried out by the NCl, calanolide A, isolated from the terrestrial plant Calophyllum lanigerum (Guttiferae), has been discovered as the most interesting natural RT inhibitor. The promise of this natural product probably relates to a novel mechanism of action. The current review describes natural products from various sources that are able to inhibit HIV-RT.

Hypoglycaemic activity of an HMG-containing flavonoid glucoside, chamaemeloside, from Chamaemelum nobile.

The 3-hydroxy-3-methylglutaric acid (HMG) containing flavonoid glucoside chamaemeloside, has been determined to have in vivo hypoglycaemic activity comparable to that of free HMG. An improved isolation scheme for obtaining chamaemeloside from Chamaemelum nobile is presented.

Antiplasmodial and cytotoxic metabolites from the Maltese sponge Agelas oroides.

From a Maltese sample of the marine sponge Agelas oroides, five compounds: oroidin (1), 2-cyano-4,5-dibromopyrrole (2), 4,5-dibromopyrrole-2-carboxylic acid (3), 4,5-dibromopyrrole-2-carboxylic acid methyl ester (4), and 4 alpha-methyl-5 alpha-cholest-8-en-3 beta-ol (5) have been isolated. For compounds 1-5, completely assigned 1H- and 13C-NMR data are reported for the first time. For 2 a single crystal X-ray crystallographic analysis proved its structure unambiguously. The X-ray analysis of 2 indicated it to crystallise in an unexpected polar space group. Biological activity assessment of all isolates indicate 5 to have moderate antiplasmodial activity, as well as being cytotoxic, and 2 to be moderately cytotoxic towards several cancer cell lines.

An unprecedented compound from the dichloromethane solubles of the tropical marine sponge Agelas oroides.

Further investigation into the natural product chemistry of the tropical marine sponge Agelas oroides has yielded the new compound 2,4,6,6-tetramethyl-3(6 H)-pyridone (1), and 2,2,6,6-tetramethyl-4-piperidone (2). Both compounds are volatile. The structures of 1 and 2 were determined from the interpretation of their 1D and 2D NMR, UV, IR, and mass spectral data.

Triterpene saponins from Cyclamen coum var. coum.

From the tubers of Cyclamen coum (Primulaceae) three new saponins, cyclaminorin (1), cyclacoumin (3) and mirabilin lactone (4) were isolated together with a known saponin, deglucocyclamin (2). The structures of the new compounds were established as 13 beta,28-epoxy-3 beta-(([beta-D-glucopyranosyl-(1-->2)]- [beta-D-glucopyranosyl-(1-->4)]-alpha-L-arabinopyranosyl) oxy) 16 alpha-hydroxy-olean-30-al (1), 13 beta,28-epoxy-3 beta-((([beta-D-xylopyranosyl-(1-->2) -beta-D-glucopyranosyl-(1-->4)]-[beta-D-glucopyranosyl-(1-->2)]- alpha-L-arabinopyranosyl)oxy)-16 alpha,23-dihydroxy-olean-30-al (3) and 16 alpha-hydroxy-3 beta-((([beta-D-xylopyranosyl-(1-->2)]- [beta-D-glucopyranosyl-1-->6)]-beta D-glucopyranosyl-(1-->4))- [beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)-oxy) olean-12-eno-30,28-lactone (4). Structure elucidattions were accomplished using both spectral (NMR, MS, IR) and chemical methods.

Cycloartane triterpene glycosides from the roots of Astragalus melanophrurius.

From the roots of Astragalus melanophrurius eight known saponins (1-8) were isolated. Based on spectral data (IR, 1H- and 13C-NMR, and FABMS), the structures were established as astrasieversianins II (1) and X (4), astragalosides I (2), II (3), IV (5) and VI (7), and cyclocanthosides E (6) and G (8). The isolates were evaluated in a broad range of bioassay systems and found to be inactive. Modest antibacterial activity was observed, however, as was immunomodulatory activity, as indicated by stimulation of isolated human lymphocytes.

Sesquiterpene content of the antibacterial dichloromethane extract of the marine red alga Laurencia obtusa.

For a sample of Laurencia obtusa, collected from the Caribbean island of Dominica, allolaurinterol was isolated for the first time and found to be responsible for the biological activity of the dichloromethane extract. For allolaurinterol, complete and assigned 1H- and 13C-NMR data are given, together with an assessment of its antibacterial, antifungal, and antialgal activities.

Marine natural products research: current directions and future potential.

Natural products research is increasingly turning to marine animals, plants, and microbes as source organisms. Several marine natural products are currently in preclinical and clinical evaluation, others show promising biological activities in in vitro and in vivo assays. Investigations of biological and chemical ecological phenomena in the marine world will contribute to a better understanding of marine habitats, and also provide a more founded basis regarding the search for pharmaceutically useful marine natural products.

Antibacterial triterpenoids from Dillenia papuana and their structure-activity relationships.

Two new oleanene-type triterpenoids, dillenic acids D and E, have been isolated from the leaves and stems of Dillenia papuana together with the new natural product 3-oxoolean-12-en-30-oic acid. Together with these compounds, the known compound, betulinic acid (3 beta-hydroxy-20(29)-lupen-28-oic acid) was isolated as the major component of the fractions studied. Dillenic acids D and E were characterized as 2,3-seco-2-oxoolean-12-en-3-methylester-30-oic acid and 1 alpha,3 beta-dihydroxyolean-12-en-30-oic acid and their nuclear magnetic resonance data were unambiguously assigned using two-dimensional nuclear magnetic resonance techniques. A comparison of antibacterial activities of these compounds with the earlier reported dillenic acids A-C indicated that, aside from a double bond in gamma- or delta-position to a carboxylic group, a ketone function in ring A of an oleanene-skeleton may be required for the observed activity.

Studies on the glycolipid content of the cyanobacterium Fischerella ambigua.

A series of monogalactosyl diacylglycerols was isolated from lipophilic extracts of Fischerella ambigua. These glycolipids were identified on the basis of chemical and spectroscopic analyses.

Biological activities of cyanobacteria: evaluation of extracts and pure compounds.

A total of 80 lipophilic and hydrophilic extracts obtained from 20 samples of cultured freshwater and terrestrial cyanobacteria were investigated for their biological activities. Of all the extracts, 26% exhibited a significant lethal effect against brine shrimp. Out of 54 extracts tested for antimicrobial activity, 78% showed antibacterial and 45% antifungal activities. Of 30 extracts tested for cytotoxicity against KB cells, none was found to be active. Bioassay-guided fractionation of the lipophilic extracts of Fischerella ambigua led to the isolation of three compounds; ambigols A (1) and B (2), and tjipanazole D (3). Compounds 1 and 2 exhibited antibacterial, antifungal, cytotoxic, molluscicidal, and anti-inflammatory, and antiviral activities. Tjipanazole D (3) showed moderate antibacterial properties.

Biological activities of selected marine natural products.

Sixty-nine natural products derived from Phaeophyta (brown algae), Rhodophyta (red algae), Porifera (sponges), Cnidaria (soft corals), and Mollusca (nudibranchs) were investigated for their cytotoxic, antimalarial, and antimicrobial effects. Fifty-six were found to mediate a positive response in one or more of these test systems.

Antibacterial triterpenoid acids from Dillenia papuana.

Three new oleanene-type triterpenoids, dillenic acids A [1], B [2], and C [3], and two known compounds, 3-oxoolean-1,12-dien-30-oic acid [4] (a new natural product) and the lupene derivative betulinaldehyde, have been isolated from the Papua New Guinean medicinal plant Dillenia papuana. The structures of the new compounds were elucidated as 2 alpha-hydroxy-3-oxoolean-12-en-30-oic acid, 2-oxo-3 beta-hydroxyolean-12-en-30-oic acid and 1 alpha-hydroxy-3-oxoolean-12-en-30-oic acid. The 1H- and 13C-nmr data of all new compounds were assigned unambiguously using a variety of 2D nmr experiments including 1H-1H-COSY, HMQC, HMBC, and NOESY experiments. Of these compounds, 1-4 showed antibacterial activities against Bacillus subtilis, Escherichia coli, and Micrococcus luteus.

Inerminosides A and B, two novel complex iridoid glycosides from Clerodendrum inerme.

The leaves of Clerodendrum inerme have yielded two new iridoid biglycosides which have been characterized as 2'-O-[5"-O-(8-hydroxy-2,6-dimethyl-2(E)-octenoyl)-beta-D-apiofuranosy l]- mussaenosidic acid (inerminoside A) [1], and 2'-O-[5"-O-(8-hydroxy-2,6-dimethyl-2(E),6(E)-octadienoyl)-beta-D- apiofuranosyl]-8-epi-loganic acid (inerminoside B [2]), respectively. Structure elucidation was carried out both chemically and spectroscopically.