TreatmentUpdate81 - Vol. 9, No. 7 - pp. 1-2; September 1997
Sean Hosein
The orange and yellow flowers of the plant calendula (Calendula officinalis) have been used in traditional medicines in parts of Europe and Asia. Calendula flowers are used to make creams for the treatment of:
* acne
* boils
* diaper rash
* dry skin
* insect bites
Homeopaths and herbalists have also prescribed calendula for throat infections, coughs and colds. The flowers are edible and are sometimes used in salads. Given its history of medicinal use, it is not surprising that researchers in Venezuela tested organic extracts of calendula to find out if the flower had any anti-HIV activity. Lab results suggest that it saved about 90% of cells from death due to HIV. Further work should be done to confirm its anti-HIV activity and ensure that a consistent amount of extract is used to produce reliable results if and when human studies begin.
Researchers collected and dried calendula flowers and made two extracts: an organic extract as well as a regular freeze-dried extract.
Results
In lab experiments low concentrations of the organic extract, but not the freeze-dried extract, protected about 90% of cells from death due to HIV. The plant extract did not appear to cause any toxicity. Calendula's anti-HIV activity occurs because the plant affects a vital viral enzyme called RT (reverse transcriptase) which is also the target of AZT and the "related" drugs, 3TC, d4T, ddC, ddI and 1592.
Inside calendula
The source of calendula's anti-HIV activity may be its pigments and antioxidants called phytochemicals. Some of these chemicals are also found in other plants such as Chinese herbs and hyssop, which also have activity against bacteria and viruses. The next step is to test the extracts in further studies to confirm these results and then perhaps begin studies in people.
Some issues to consider
* Although organic extracts of calendula are available in health food stores, the anti-HIV activity of these specific preparations has not been tested, so it is not clear how much of them researchers can use in experiments on people.
* By itself, the calendula extract used in the study was not 100% protective. Future studies in people would require combining it with other compounds that also have anti-HIV activity, preferably against targets other than RT.
* Since there are reports of increasing resistance by HIV against drugs such as AZT that affect RT, extracts of calendula could possibly play a role in boosting the antiviral defences against HIV.
REFERENCES:
1. Kalvatchev Z, Walder R, Garzaro D. Anti-HIV activity of extracts from Calendula officinalis flowers. Biomedicine and Pharmacotherapy 1997;51:176-180.
2. Dunlap L. A healing flower: Calendula Officinalis. [Internet] Harvest Times June 1996.
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