Isolation, purification, and partial characterization of prunellin, an anti-HIV component from aqueous extracts of Prunella vulgaris.

Prunellin, an anti-HIV active compound, was isolated from aqueous extracts of the Chinese medicinal herb, Prunella vulgaris, and purified to chromatographic homogeneity. Infrared and NMR spectroscopy identified prunellin as a polysaccharide. Elemental analyses, precipitation with calcium(II), barium(II), or 9-aminoacridine suggest a sulfated polysaccharide. Paper chromatography of the exhaustively hydrolyzed material indicates the presence of glucose, galactose, xylose, gluconic acid, galactonic acid and galactosamine as the constituent monosaccharides. The molecular size of prunellin, as determined by gel permeation chromatography and the Squire method on Sephadex G-75, is about 10 kDa.

Dextran sulfate as an inhibitor against the human immunodeficiency virus.

Dextran sulfate (DS) is a potent inhibitor of the growth of human immunodeficiency virus type 1 (HIV-1) in the H9 cell. Its minimal inhibitory concentration is about 1 microgram/ml. Its therapeutic index is greater than or equal to 200 which is higher than that of 38 for zidovudine. At the ID100 range, DS blocks the synthesis of HIV-1 antigens completely for at least 21 days; zidovudine at the subtoxic concentration of 3 micrograms/ml is incapable of achieving such a complete blockage. DS is still active when added to H9 cell cultures 4 hr after the addition of HIV-1. DS does not inactivate extracellular HIV-1 and is incapable of inducing interferons. It interferes partially with the infection of the H9 cells by the HIV-1. It inhibits the activity of HIV-1 reverse transcriptase. These activities may account, at least in part, for the inhibitory activity of dextran sulfate against the HIV-1. DS has a narrow antiviral spectrum; it is noninhibitory to the herpes simplex, vesicular stomatitis, polio, or adeno viruses. Dextran is not inhibitory to HIV-1. After sulfonation, the sulfonated dextran is highly inhibitory. Therefore, the sulfate group in the DS molecule appears to be essential for its anti-HIV-1 activity. The molecular weights of DS within the range 4000 to 12,000 do not appear to influence its anti-HIV potency.

Isolation, purification and partial characterization of an active anti-HIV compound from the Chinese medicinal herb viola yedoensis.

The dimethylsulfoxide extract of the Chinese medicinal herb Viola yedoensis demonstrates high inhibitory activity toward HIV-1 in vitro. The corresponding methanol extract also showed inhibitory activity but not as high as the dimethylsulfoxide extract. Anti-HIV activity in the extracts is accompanied by cytotoxicity, and we describe here the separation of the cytotoxic material from the active fraction. We also describe the procedure for isolation, purification, and separation of the active component from crude extracts of V. yedoensis as well as details of its activity against HIV-1. The UV-visible, infrared (IR) and proton nuclear magnetic resonance (NMR) data and certain other characteristics of the active compound are also presented. Initial chemical tests and the proton NMR and IR spectra indicate a high molecular weight sulphonated carbohydrate polymer, and chromatographic evidence suggests an MW between 10,000 and 15,000.

The use of N-methylprotoporphyrin dimethyl ester to inhibit ferrochelatase in Rhodopseudomonas sphaeroides and its effect in promoting biosynthesis of magnesium tetrapyrroles.

N-Methylprotoporphyrin dimethyl ester inhibits ferrochelatase in isolated membranes of Rhodopseudomonas sphaeroides at low concentrations (around 10 nm). Full inhibition developed after a short lag phase. The inhibition was non-competitive with porphyrin substrate. Addition of inhibitor to growing cultures of Rps. sphaeroides caused a decrease (near 40%) in cytochrome content and a severe inhibition of ferrochelatase; the excretion of haem into the medium by cell suspensions was also severely inhibited. The addition of N-methylprotoporphyrin dimethyl ester to suspensions of photosynthetically competent Rps. sphaeroides Ga caused excretion of Mg-protoporphyrin monomethyl ester. When added to mutants V3 and O1, magnesium divinylphaeoporphyrin a5 monomethyl ester and 2-devinyl-2-hydroxyethylphaeophorbide a were excreted, with maximum effect at around 3 microM-inhibitor in the medium. The results are interpreted to suggest that the inhibitor decreases concentration of intracellular haem, which normally controls the activity of 5-aminolaevulinate synthetase. Unregulated activity of this enzyme leads to overproduction of protoporphyrin, which is diverted to the bacteriochlorophyll pathway. Further control operates at magnesium protoporphyrin ester conversion in normal cells.