Natural Products Articles

Unripe avocado fruit (Persea americana) was subjected to a bioactivity-directed fractionation, as monitored via the brine shrimp lethality assay, to isolate three major bioactive constituents. All three of the compounds have a 1,2,4-triol moiety and a long aliphatic chain that terminates as either an alkane, alkene, or alkyne, respectively. All have activity against six human tumor cell lines in culture and show selectivity for human prostate adenocarcinoma (PC-3) cells.

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Public interest in attaining or maintaining health with “natural” remedies has steadily increased during the last few decades. The demand for phytopharmaceuticals, otherwise known as plant or herbal drugs, to treat disease has become a worldwide phenomenon. In Europe, the market for botanicals is well developed and involves prescription sales in some countries. China and Japan also have long traditions of using herbal drugs. In the U.S., interest continues to rise as more Americans choose alternative medicines and self-treatment approaches for their health.

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Quantities of material required for structural analysis were reduced substantially following the introduction of 3 mm microinverse and microdual NMR probes in 1992. We now report the first very low-level results obtainable with a new 1.7 mm submicro-inverse-detection gradient or SMIDG NMR probe. Using this technology at 600 MHz, it was possible to fully characterize an 8% impurity contained in a 0.55 mol sample of cryptolepine that had been standing in excess of 2 years since its initial isolation. The impurity was unequivocally identified as cryptolepinone through the concerted interpretation of GHSQC, GHMBC, homonuclear TOCSY, and ROESY spectra in conjunction with APCI LC/MS and CID data acquired from a portion of the serial dilution solution used to prepare the NMR sample.

American Chemical Society Resveratrol (3,5,4'-trihydroxy-trans-stilbene; Scheme 1) is a natural product present at concentrations up to 100 M in red wines. It is reported to have antiinflammatory, cardiovascular protective, and cancer chemopreventive properties and was shown to target prostaglandin H2 synthases (COX-1 and COX-2).

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Numerous hormonal compounds have been made available as over-the-counter nutritional supplements in the United States as a result of the Dietary Supplement Health and Education Act (DSHEA) of 1994. Although many hormonal supplements (e.g., androst-5-en-3 -ol-17-one (DHEA) and melatonin, in particular) have been well-documented with regard to source, safety, and potential benefit, some other compounds have not. An esoteric member of this category, 5-androst-1-ene-3 , 17-diol (1), has not been demonstrated to be present in the food supply and may, therefore, not be considered a nutritional supplement.

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Clivorine (1) and ligularine (2), two hepatotoxic otonecine-type pyrrolizidine alkaloids isolated from Ligularia hodgsonii, an antitussive traditional Chinese medicine, were investigated in CDCl3 and D2O by various NMR techniques to delineate why this type of alkaloid displays uncharacteristic solubility properties by dissolving in both nonpolar organic and aqueous solutions. The results demonstrated that both alkaloids exist in a non-ionized form in CDCl3, but in an ionized form in D2O, suggesting that this unique dual solubility may play a role in the intoxication resultant from consumption of water extracts of herbs, including herbal teas, containing otonecine-type pyrrolizidine alkaloids





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Herbal medicinal products exist in all Member States of the European Union (EU), although their importance varies considerably from o­ne country to another. They do not represent a homogeneous group. Generally speaking, there are either fully licensed medicinal products with efficacy proven by clinical studies or by bibliography (in accordance with Article 4.8 a (ii) of Council Directive 65/65/EEC) or products with a more or less simplified proof of efficacy according to their national use. Although these two categories exist in many Member States, there are major discrepancies between the Member States in the classification of individual herbal drug preparations and products into o­ne of these categories as well as in the requirements for obtaining a marketing authorisation.

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The screening of crude natural product extracts and combinatorial libraries for activities has been a major source of biologically active compounds for drug development efforts. However, whole extract screens can be problematic when multiple, potentially interfering activities or nonspecifically active compounds, such as tannins or leptins, are present. The ability to separate and assess individually such activities without macroscopic isolation represents an extremely useful method for drug discovery.

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