[jasonschaffin]

: J Steroid Biochem Mol Biol. 2006 Aug;100(4-5):167-76. Epub 2006 Jul 13. Links
Antiestrogenic activities of Ginkgo biloba extracts.Oh SM, Chung KH.
College of Pharmacy, Sungkyunkwan University, 300 Cheoncheon dong, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea.

Most climacteric and postmenopausal women appear to have vasomotor symptoms as well as a high risk of osteoporosis and cardiovascular disease. Although exogenous estrogens can reduce these symptoms, women are reluctant to use hormone replacement therapy (HRT) due to its undesirable side effects, such as irregular bleeding and an increased risk of breast cancer. A previous study suggested that Ginkgo biloba extracts (GBE) have estrogenic activity and might be suitable as an alternative to HRT. However, there are no reports of the preventive effect of GBE on breast cancer, which is the side effect of classical HRT. In this study, it was confirmed that GBE exhibits estrogenic and antiestrogenic activity depending on the E2 and GBE concentration, via estrogen receptor (ER)-dependent and ER-independent pathways. In addition, GBE reduced the E2 levels by stimulating the E2 metabolism and inhibiting E2 synthesis, which indicates that GBE can induce antiestrogenic activity via the depletion of E2. Furthermore, GBE might have similar action to selective arylhydrocarbon receptor modulators (SAhRMs), which induce antiestrogenic activity through cross-talk between the arylhydrocarbon receptor (AhR) and ER. In conclusion, GBE has a biphasic effect on estrogen, and can be considered as a potential alternative to HRT with chemopreventive effects on breast cancer. However, further studies on animals and humans will be required.

PMID: 16842996 [PubMed - indexed for MEDLINE]

Life Sci. 2004 Jan 30;74(11):1325-35. Links
Estrogenic activities of Ginkgo biloba extracts.Oh SM, Chung KH.
College of Pharmacy, Sungkyunkwan University, 300, Chunchun-dong, Jangan-Ku, Suwon, Kyunggido 440-746, South Korea.

Ginkgo biloba extracts (GBE) are extracted from the leaves of Ginkgo biloba tree. GBE contains 24% of phytoestrogens, which is kaempferol, quercetin, and isorhamnetin. It has been reported that phytoestrogens could be a part of SERMs (Selective estrogen receptor modulators) and possibly the alternative HRT (Hormone replacement therapy) for postmenopausal women. The goal of this study was to investigate the potencies of GBE and its major components (quercetin, kaempferol, isorhamnetin) for estrogenic effect, which confirms the capacity as an alternative HRP. It was found that GBE and its major components exerted a dual action on ER-alpha and ER-beta in competitive binding assay. The binding affinity of these chemicals to ER-beta was higher than to ER-alpha. In the E-screen assay, these chemicals induced cell proliferation in ER-positive MCF-7 cell, but not in ER-negative MDA-MB-231 cells. The cell proliferation induced by these chemicals was blocked by tamoxifen. Also, GBE and its major components induced pS2 and PR (progesterone receptor) transcription in MCF-7 cells. Therefore these results indicated that GBE and its major components had the weak estrogenic activities through the estrogen response pathway by an interaction with the ER. In conclusion, we provided the evidence of potential estrogenic activities of GBE, which could be useful as an alternative HRP. However, further studies are required to assess the physiological significance of GBE in animals and humans.

PMID: 14706564 [PubMed - indexed for MEDLINE]

[derick]

no ****. thats pretty sweet

[jasonschaffin]

really guys, 70 views and one response? if this is stupid at least tell me its stupid. seems pretty sweet to me though. I guess I'll go ask dinoiii.

[pudzian2]

interesting....

[drksun]

nice find, but what doses were used?

[datBtrue]

The studies showed an increase in estrogenic activities and a decrease in the good estrogen E2 (possibly depletion of E2). This is not a good combination...especially if you want to keep your sex drive.

[Schism]

Originally Posted by datBtrue

The studies showed an increase in estrogenic activities and a decrease in the good estrogen E2 (possibly depletion of E2). This is not a good combination...especially if you want to keep your sex drive.

I agree with datBtrue. Still that's an interesting study.

[dinoiii]

Answered over at Lean Bulk.


D_

[methodice]

Where is lean bulk? Dino can you answer my question about zona etc in the other thread you answered about a week ago?

[bioman]

Waaaay too early to tell on this one. LOTS of herbs contain phytoestrogens..in fact I dare say most of the really popular ones have some phytoestrogen-type activity. They all differ in their modalities and are, IMO, probably more nuanced in their actions than science can possibly test for at the moment.

[saludable24]

Originally Posted by datBtrue

The studies showed an increase in estrogenic activities and a decrease in the good estrogen E2 (possibly depletion of E2). This is not a good combination...especially if you want to keep your sex drive.

Possibly combine it with DIM to filter out bad estrogens and raise E2? I guess it really depends on the degree of estrogenic activity it causes along with many other things. I used the NOW brand and felt it did booste my libido a bit.

[jasonschaffin]

Originally Posted by datBtrue

The studies showed an increase in estrogenic activities and a decrease in the good estrogen E2 (possibly depletion of E2). This is not a good combination...especially if you want to keep your sex drive.

My thoughts were that since it showed weak estrogenic activity it may be good during/after an aromatizing cycle. Also it showed activity at both alpha and beta receptors, something I'm pretty sure I read was one of the problems with the resveratrol as a SERM bandwagon everyone jumped on. As for the E2, it didn't say if they checked the other estrogens in the abstract, could be a decrease in all estrogens. Just trying to stir up some discussion I guess. Dana did a good job answering over at ******** though.

[jasonschaffin]

Originally Posted by saludable24

Possibly combine it with DIM to filter out bad estrogens and raise E2? I guess it really depends on the degree of estrogenic activity it causes along with many other things. I used the NOW brand and felt it did booste my libido a bit.

I was thinking something like that.
Ginko + IC3 + natty test booster + possibly AI
could be a decent OTC PCT. But alas doesn't seem like ginkgo is that promising after all.

[JohnnyBGood]

Originally Posted by saludable24

Possibly combine it with DIM to filter out bad estrogens and raise E2? I guess it really depends on the degree of estrogenic activity it causes along with many other things. I used the NOW brand and felt it did booste my libido a bit.

Yea, but why not just take the DIM since it already accomplishes this? What good would the ginko do here?

[datBtrue]

I use a little ginkgo to reduce caffeine or stimulant induced headaches...it opens up those constricted blood vessels. But that is all I use it for.

[strategicmove]

Originally Posted by dinoiii

Answered over at Lean Bulk.


D_

I guess it is up to you how easy you want to make it for people here to see your response. Personally, I do not see why you cannot "copy-and-paste" the answer here. I definitely would not go to Lean Bulk just to read your answer. I am sure others see it differently. Just my 2.01 cents. No hard feelings

[strategicmove]

Originally Posted by datBtrue

I use a little ginkgo to reduce caffeine or stimulant induced headaches...it opens up those constricted blood vessels. But that is all I use it for.

1) A "little" is relative. 10mg, 100mg, 300mg daily?
2) The point is that, once ginkgo is in your body, you cannot tell it what to do. If it has SERM-type activites, and I am not necessarily saying it does, you have no way of restricting it's activity to just "opening up constricted blood vessels"
3) I find ginkgo has many cool benefits, but was surprised