Article: St John's Wort can cause photo-oxidative damage the the lens

1: Photochem Photobiol. 2003 Jul;78(1):88-92. Related Articles,
Links

Focal length variability and protein leakage as tools for measuring
photooxidative damage to the lens.

Wahlman J, Hirst M, Roberts JE, Prickett CD, Trevithick JR.

Department of Biochemistry, University of Western Ontario, London,
Ontario, Canada.

Hypericin is the ingredient used to standardize the popular over-the-
counter antidepressant medication St. John's Wort. Because hypericin
readily produces singlet oxygen and other excited state
intermediates, it is a very efficient phototoxic agent in the eye
that can potentially induce the development of the cataract
photooxidative mechanism. Hypericin absorbs in the UV and visible
ranges, binds to the lens crystallins (alpha, beta and gamma) and
damages these proteins through a photooxidative mechanism. Effects
were measured previously using fluorescence, UV and mass
spectrometry. We report here two additional methods to monitor lens
damage: (1) measuring focal length variability using a ScanTox
instrument and (2) measuring protein leakage from the damaged lens.
Because nonenzymic glycation results in free radical production, we
chose to use elevated glucose concentrations as a convenient model
for studying oxidative stress. To compare and contrast photooxidative
damage against oxidative damage to the lens, we also measured the
focal length variability and protein leakage induced by the presence
of elevated glucose concentrations. We found that the total
accumulated protein leakage was positively correlated (r = 0.9) with
variability in focal length. Lenses treated with hypericin and
irradiated with UVB had an increase in focal length variability as
compared with the lenses that were only UVB-irradiated. Lenses
without UVB irradiation had much lower focal length variability than
irradiated lenses. For non-hypericin-treated lenses, UVB-irradiated
lenses had a larger variability (4.58 mm) than the unirradiated
lenses (1.78 mm). The lenses incubated in elevated glucose
concentrations had a focal length variability (3.23 mm) equivalent to
that of the unirradiated hypericin-treated lenses (3.54 mm). We
conclude that photooxidative damage by hypericin results in changes
in the optical properties of the lens, protein leakage and finally
cataract formation. In contrast to this, high concentrations of
glucose induced protein leakage but not changes in optical properties
or the opacity associated with a cataract. This work provides further
evidence that people should protect their eyes from intense sunlight
when taking St. John's Wort.

PMID: 12929754 [PubMed - in process]

 

The FDA has a Public Health Advisory out on St. John's Wort as well.
It has some nasty drun interactions. Personally, I wouldn't get near
the stuff.

http://www.fda.gov/cder/drug/advisory/stjwort.htm

FDA PUBLIC HEALTH ADVISORY
February 10, 2000

Subject: RISK OF DRUG INTERACTIONS WITH ST JOHN'S WORT AND INDINAVIR
AND OTHER DRUGS

FDA/Center for Drug Evaluation and Research

<snip>

"Based on this study and reports in the medical literature, St. John's
wort appears to be an inducer of an important metabolic pathway,
cytochrome P450. As many prescription drugs used to treat conditions
such as heart disease, depression, seizures, certain cancers or to
prevent conditions such as transplant rejection or pregnancy (oral
contraceptives) are metabolized via this pathway, health care
providers should alert patients about these potential drug
interactions to prevent loss of therapeutic effect of any drug
metabolized via the cytochrome P450 pathway."

<snip>

-sqrrlbird