Science Forums 2

[Michaelangelica]

Abstract Extracts of 13 Korean seaweeds, previously shown to contain antiviral activity, were investigated in more detail in order to learn the nature of the antiviral compounds and their mechanisms of action.
One extract, from Codium fragile, was active against all three test viruses (herpes simplex, HSV; Sindbis, SINV; polio), whereas the others were more selective. Thus four species, Enteromorpha linza, Colpomenia bullosa, Scytosiphon lomentaria, and Undaria pinnatifida, were active against HSV and SINV, but not poliovirus.
The other eight were active against either HSV or SINV.
In all cases there was evidence for photosensitizers, since the antiviral activities required or were enhanced substantially by light.
In general UVA (long wave ultraviolet) was much more effective than visible light in promoting activity, although the extract of Sargassum sagamianum could be activated equally by either.
In experiments to determine the site of action of these antiviral extracts, the predominant activity was virucidal (i.e. direct inactivation of virus particles), rather than inhibition of virus replication, although Sargassum sagamianum also could protect cells against subsequent virus infection.
These results imply that different antiviral compounds are present among the extracts, and furthermore the activities cannot be explained in terms of common ingredients such as polysaccharides or tannins.
We suggest that seaweeds may be a source of potentially useful and interesting antiviral compounds.

http://www.springerlink.com/content/g34g44887m53401w/

This is an interesting read
http://www.pubmedcentral.nih.gov/art...gi?artid=88925

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. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.
. . .
FOR THE CHEMISTS
Plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their oxygen-substituted derivatives (76).
Most are secondary metabolites, of which at least 12,000 have been isolated, a number estimated to be less than 10% of the total (195).
In many cases, these substances serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores.
Some, such as terpenoids, give plants their odors; others (quinones and tannins) are responsible for plant pigment.
Many compounds are responsible for plant flavor (e.g., the terpenoid capsaicin from chili peppers), and some of the same herbs and spices used by humans to season food yield useful medicinal compounds (Table 1).

Useful antimicrobial phytochemicals can be divided into several categories, described below and summarized in Table 2.
Anyone with, or has afriend with, AIDS might like to look these references up.
Eating licorice can't be that horrible atreatment.
. . .
Effective therapies for HIV infection are being sought far and wide, in the natural world as well as in laboratories. As one example of in vivo anti-HIV studies, infection in mice has been studied.
Glycyrrhizin, found in Glycyrrhiza plants (the source of licorice), extended the life of the retrovirus-infected mice from 14 to 17 weeks (242). A crude extract of the cactus Opuntia streptacantha had marked antiviral effects in vitro, and toxicity studies performed in mice, horses, and humans found the extract to be safe (3).

The scope of studies of anti-HIV plant extracts is too broad to handle in detail in the present review, but Table 6 summarizes many of the compounds studied to date as well as their purported targets of action. The interested reader is referred to several useful reviews (36, 155, 172, 217).

Tobacco farmers might be able to turn to growing tobacco for its anti-viral properties!
SEE:
http://www.pnas.org/cgi/reprint/87/2/588.pdf