Natural Products Articles

Various hydrophilic polymers from synthetic origin such as methylcellulose, PEGs, HPMC as well as those from natural world such as guar gum, tragacanth, xanthan gum have been used to formulate oral sustained release formulations. Psyllium husk has the ability to swell 10-14 times of its original volume and form a hydrogel.

Seed oils of Gynandropsis gynandra, Impatiens balsamina, Celastrus paniculata, Embelia ribes and Mucuna pruriens were investigated for their anthelmintic property against Pheritima posthuma . Three concentrations (10, 50 and 100 mg/ml) of each oil were studied in a bioassay, which involved the determination of time of paralysis and time of death of the worm.

Melothria maderaspatana (Linn) Cogn, a plant drug of Siddha medicine, is an annual monoecious tendril climber, belonging to the family Cucurbitaceae, mostly prevalent in South India. It is commonly called Musumusukkai in Tamil. Preliminary phytochemical screening of the plant revealed the presence of phytochemical constituents such as coumarins, flavonoids.

Hybanthus enneaspermus Muell, belonging to family Violaceae, was investigated to evaluate in vitro antibacterial activity of aqueous, ethanolic, petroleum ether and chloroform extracts against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis and Staphylococcus aureus .

Dendrobatid frogs of Central and South America have been a rich source of a wide variety of biologically active alkaloids, comprising over 20 structural classes; code names for the over 500 alkaloids found in frog skins are provided in a recent review. In 1976, a C19 alkaloid of molecular weight 275, which was code-named 275A (1), was found to be a major alkaloid in skin extracts of a red and black-banded dendrobatid frog, Dendrobates lehmanni Myers and Daly, 1976, collected in montane forest near Cali, Colombia. The frog, known previously o­nly from street markets in Cali, had been considered another populational variant of the extremely variable species Dendrobates histrionicus Berthold, 1845.

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All rights reserved. The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed.

This article shows a number of interesting new chemical structures, some of which are extremely potent antibacterial agents--possible explanations for how sharks deal with infections.

Seven new aminosterols related to squalamine were isolated from the liver of the dogfish shark Squalus acanthias. These aminosterols possess a relatively invariant cholestane skeleton with a trans AB ring junction, a spermidine or spermine attached equatorially at C3, and a steroidal side-chain that may be sulfated. The structure of the lone spermine conjugate, was confirmed by its synthesis from (5,7,24R)-7-hydroxy-3-ketocholestan-24-yl sulfate. Some members of this family of aminosterols exhibit a broad spectrum of antimicrobial activity comparable to squalamine.

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Synthetic excipients frequently offer advantages over all-natural compounds.



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Naturally occurring substances that appear to repel a leaf-eating insect pest have been found in the leaves of Spanish cedar trees. Veitch and co-workers say that selecting seedlings with high concentrations of these previously unidentified substances, known as limonoids, may help in the production of plantation-raised Spanish cedars while also reducing the need for synthetic insecticides.

"The four compounds we identified are new to science," said Philip C. Stevenson, Ph.D., natural product chemist at the Jodrell Laboratory of the Royal Botanic Gardens and the Natural Resources Institute at the University of Greenwich, and the study's primary coordinator. "As well, our study was the first to examine Spanish cedar leaves for the particular group of substances (known as triterpenoids, which include limonoids) in tandem with the first extensive field observations of insect feeding patterns o­n Spanish cedars.

Natural products from plants remain at the core of modern medicinal chemistry.For all the biomedical promise of genetic engineering and combinatorial chemistry, the greenhouse, the garden, and the jungle remain key sources of current pharmaceuticals and future drug candidates. Whether directly purified from nature or chemically modified in the lab, these compounds are at the heart of the world pharmacopoeia and the source molecules for directed, knowledge-based medicinal chemistry.

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