Saw Palmetto Clinical Studies:
Saw Palmetto Study #1:
This study suggests that Saw Palmetto extract
inhibited both type one and two forms of 5 alpha-reductase.
Title: Human prostatic steroid 5 alpha-reductase isoforms -a
comparative study of selective inhibitors.
Iehlé C; Délos S; Guirou O; Tate R; Raynaud JP; Martin PM
J Steroid Biochem Mol Biol, 54: 5-6, 1995 Sep, 273-9
The present study describes the independent expression of
the type 1 and 2 isoforms of human 5 alpha-reductase in the
baculovirus-directed insect cell expression system and the
selectivity of their inhibition. The catalytic properties
and kinetic parameters of the recombinant isozymes were
consistent with published data. The type 1 isoform displayed
a neutral (range 6-8) pH optimum and the type 2 isoform an
acidic (5-6) pH optimum. The type 2 isoform had higher
affinity for testosterone than did the type 1 isoform (Km =
0.5 and 2.9 microM, respectively). Finasteride and
turosteride were selective inhibitors of the type 2 isoform
(Ki (type 2) = 7.3 and 21.7 nM compared to Ki (type 1) = 108
and 330 nM, respectively). 4-MA and the lipido-sterol
extract of Serenoa repens (LSESr) markedly inhibited both
isozymes (Ki (type 1) = 8.4 nM and 7.2 micrograms/ml,
respectively; Ki (type 2) = 7.4 nM and 4.9 micrograms/ml,
respectively). The three azasteroids were competitive
inhibitors vs substrate, whereas LSESr displayed
non-competitive inhibition of the type 1 isozyme and
uncompetitive inhibition of the type 2 isozyme. These
observations suggest that the lipid component of LSESr might
be responsible for its inhibitory effect by modulating the
membrane environment of 5 alpha-reductase. Partially
purified recombinant 5 alpha-reductase type 1 activity was
preserved by the presence of lipids indicating that lipids
can exert either stimulatory or inhibitory effects on human
Palmetto Study #2:
This study shows Saw Palmetto inhibited the
formation of the Testostrone metabolites studied.
Testosterone metabolism in primary cultures of human
prostate epithelial cells and fibroblasts.
Délos S; Carsol JL; Ghazarossian E; Raynaud JP; Martin PM
J Steroid Biochem Mol Biol, 55: 3-4, 1995 Dec, 375-83
We compare testosterone (T) metabolism in primary cultures
of epithelial cells and fibroblasts separated from benign
prostate hypertrophy (BPH) and prostate cancer tissues. In
all cultures, androstenedione (delta 4) formed by oxidation
of T by 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD)
represented 80% of the metabolites recovered. The amounts of
5 alpha-dihydrotestosterone (DHT), formed by reduction of T
by 5 alpha-reductase (5 alpha-R), were small: 5 and 2% (BPH)
and 8 and 15% (adenocarcinoma) for epithelial cells and
fibroblasts, respectively. Northern blot analysis of total
RNA from epithelial cells (BPH or adenocarcinoma) attributed
the reductive activity to the 5 alpha-reductase type 1
isozyme and oxidative activity to the 17 beta-HSD type 2. In
cancer fibroblasts, only little 17 beta-HSD type 2 mRNA was
detected. The 5 alpha-reductase inhibitors, 4-MA (17
alpha-androstan-3-one) and finasteride, inhibited DHT
formation with a preferential action of 4-MA on epithelial
cells (BPH or adenocarcinoma) and of finasteride on
fibroblasts from adenocarcinoma. Neither inhibitor acted on
delta 4 formation. On the other hand, the lipido-sterol
extract of Serenoa repens (LSESr, Permixon, Saw Palmetto)
inhibited the formation of all the T metabolites studied
[IC50 S = 40 and 200 micrograms/ml (BPH) and 90 and 70
micrograms/ml (adenocarcinoma) in epithelial cells and
fibroblasts, respectively]. These results have important
therapeutic implications when selecting appropriate
treatment options for BPH.
Nettles Clinical Study:
study shows that Nettles extract inhibits enzymes such as 5
alpha reductase (the enzyme that causes testosterone to convert
to DHT). It is the DHT metabolite of testosterone that is known
to cause excess hair loss at the top of the head.
R. Hartmann et al.
The extract of nettle root (Urtica
dioica L., Urticaceae) partially blocked the action of two
enzymes involved in the body's production of dihydrotestosterone
and estrogen. The in vitro (laboratory) study showed that
nettle root extract was effective in inhibiting these two
enzymes (5alpha-reductase and aromatase).
Dr. A Vogel, a Swiss herbalist know throughout the world,
advocates Nettle for stimulating hair growth and Dr.
Rudolf Fritz Weiss, M.D., the dean of German herbal physicians
and author of Herbal Medicine also supports the use of
Nettles for those with thinning hair.
Green Tea (Equisetum)
This study shows that Green Tea has compounds in it that are
potent inhibitors of type 1 alpha-reductase.
inhibition of steroid 5 alpha-reductase isozymes by tea
epicatechin-3-gallate and epigallocatechin-3-gallate.
Liao S, Hiipakka RA. Ben May Institute, University of
Chicago, IL 60637, USA.
Biochem Biophys Res Commun 1995 Sep 25;214(3):833-8
Inhibitors of 5 alpha-reductase may be
effective in the treatment of 5 alpha-dihydrotestosterone-dependent
abnormalities, such as benign prostate hyperplasia, prostate
cancer and certain skin diseases. The green tea catechins,
(-)epigallocatechin-3-gallate and (-)epicatechin-3-gallate,
but not (-)epicatechin and (-)epigallocatechin, are potent
inhibitors of type 1 but not type 2 5 alpha-reductase.
(-)Epigallocatechin-3-gallate also inhibits accessory sex
gland growth in the rat. These results suggest that certain
tea gallates can regulate androgen action in target organs.
Capsicum Clinical Study:
This study shows that the active
principle that causes the heat in capsicum is a crystalline
alkaloid generically called
capsaicin induces the release of
substance P(SP) which is believed to play an important role
in the murine hair growth and cycle.
Coapplication of Capsaicin and Minoxidil on the Murine Hair
Won-Soo Lee, Hyung Jin
Ahn, Young Hee Kim Department of Dermatology. Yonsei
University Wonju College of Medicine, Wonju. Korea
Capsaicin induces the release of substance P(SP)
which is believed to play an important role in murine hair
growth and cycle. Minoxidil, the only approved topical hair
drug having direct hair growth effect, has therapeutic
limitation because it stimulates mainly vellus hair
regrowth, not thick coarse terminal hairs... We devied the
mice into 4 groups, i.e., control group, capsaicin group,
minoxidil group, and coapplied group. And then, we examined
the hair growth macroscopically, and the percentage of the
area of hair regrowth by image analysis using
phototrichogram at the 0, the 5th, 10th, 15th, 20th, 25th,
and 30th day. Also we examined the morphologic changes of
hair follicles and subcutis, and the number of mast cells by
microscopy, and[methyl-3H] thymidine uptake by scintillation
counter. In this study, we observed that capsaicin can not
only induce the anagen phase quickly, but also sustain
constant effect on the linear hair growth.