TulsaTalons
Member
whats the deal with grapefruit juice? is it suposed to increase absorption of phs or something?
grapefruit juice?
- Thread starter TulsaTalons
- Start date
mikemd21289
Member
wrong section brotha but short answer is yes
TulsaTalons
Member
mikemd21289
Member
No prob wasn't trying to neg you or anything btw, just figured the nutrition section would get you more responses. Also if you search 'grapefruit juice' in the custom search there are already a few threads on this topic. Also a google search of 'grapefruit juice and Cytochrome P450 CYP3A4' will give you a more scientific answer
One Example Study
Inhibition Selectivity of Grapefruit Juice Components on Human Cytochromes P450
References and further reading may be available for this article. To view references and further reading you must purchase this article.
Wichittra Tassaneeyakulb, a, Lian-Qing Guob, Katsuyuki Fukudac, Tomihisa Ohtad and Yasushi Yamazoeb, 1
a Department of Pharmacology, Faculty of Medicine, KhonKaen University, KhonKaen, 40002, Thailand
b Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
c Department of Drug Metabolism and Pharmacokinetics, Discovery Research Laboratory, Tanabe Seiyaku Co., Ltd, 2-2-50, Kawagishi, Toda-shi, Saitama, 335-8505, Japan
d Division of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1, Takara-tyo, Kanazawa, 920-0934, Japan
Received 10 January 2000;
revised 20 March 2000.
Available online 27 March 2002.
Abstract
Five compounds including furanocoumarin monomers (bergamottin, 6′,7′-dihydroxybergamottin (DHB)), furanocoumarin dimers (4-[[6-hydroxy-7[[1-[(1-hydroxy-1-methyl)ethyl]-4-methyl-6-(7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl- 2-octenyl]oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-1) and 4-[[6-hydroxy-7[[4-methyl-1-(1-methylethenyl)-6-(7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl-2-octenyl]oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-4)), and a sesquiterpene nootkatone have been isolated from grapefruit juice and screened for their inhibitory effects toward human cytochrome P450 (P450) forms using selective substrate probes. Addition of ethyl acetate extract of grapefruit juice into an incubation mixture resulted in decreased activities of CYP3A4, CYP1A2, CYP2C9, and CYP2D6. All four furanocoumarins clearly inhibited CYP3A4-catalyzed nifedipine oxidation in concentration- and time-dependent manners, suggesting that these compounds are mechanism-based inhibitors of CYP3A4. Of the furanocoumarins investigated, furanocoumarin dimers, GF-I-1 and GF-I-4, were the most potent inhibitors of CYP3A4. Inhibitor concentration required for half-maximal rate of inactivation (KI) values for bergamottin, DHB, GF-I-1, and GF-I-4 were calculated, respectively, as 40.00, 5.56, 0.31, and 0.13 μM, whereas similar values were observed on their inactivation rate constant at infinite concentration of inhibitor (kinact, 0.05–0.08 min−1). Apparent selectivity toward CYP3A4 does occur with the furanocoumarin dimers. In contrast, bergamottin showed rather stronger inhibitory effect on CYP1A2, CYP2C9, CYP2C19, and CYP2D6 than on CYP3A4. DHB inhibited CYP3A4 and CYP1A2 activities at nearly equivalent potencies. Among P450 forms investigated, CYP2E1 was the least sensitive to the inhibitory effect of furanocoumarin components. A sesquiterpene nootkatone has no significant effect on P450 activities investigated except for CYP2A6 and CYP2C19 (Ki = 0.8 and 0.5 μM, respectively).
Author Keywords: cytochromes P450-inhibition; drug–grapefruit juice interaction; furanocoumarins; CYP3A4
1 To whom correspondence should be addressed. Fax: 81-22-2176826. E-mail: [email protected].
One Example Study
Inhibition Selectivity of Grapefruit Juice Components on Human Cytochromes P450
References and further reading may be available for this article. To view references and further reading you must purchase this article.
Wichittra Tassaneeyakulb, a, Lian-Qing Guob, Katsuyuki Fukudac, Tomihisa Ohtad and Yasushi Yamazoeb, 1
a Department of Pharmacology, Faculty of Medicine, KhonKaen University, KhonKaen, 40002, Thailand
b Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
c Department of Drug Metabolism and Pharmacokinetics, Discovery Research Laboratory, Tanabe Seiyaku Co., Ltd, 2-2-50, Kawagishi, Toda-shi, Saitama, 335-8505, Japan
d Division of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1, Takara-tyo, Kanazawa, 920-0934, Japan
Received 10 January 2000;
revised 20 March 2000.
Available online 27 March 2002.
Abstract
Five compounds including furanocoumarin monomers (bergamottin, 6′,7′-dihydroxybergamottin (DHB)), furanocoumarin dimers (4-[[6-hydroxy-7[[1-[(1-hydroxy-1-methyl)ethyl]-4-methyl-6-(7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl- 2-octenyl]oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-1) and 4-[[6-hydroxy-7[[4-methyl-1-(1-methylethenyl)-6-(7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl-2-octenyl]oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-4)), and a sesquiterpene nootkatone have been isolated from grapefruit juice and screened for their inhibitory effects toward human cytochrome P450 (P450) forms using selective substrate probes. Addition of ethyl acetate extract of grapefruit juice into an incubation mixture resulted in decreased activities of CYP3A4, CYP1A2, CYP2C9, and CYP2D6. All four furanocoumarins clearly inhibited CYP3A4-catalyzed nifedipine oxidation in concentration- and time-dependent manners, suggesting that these compounds are mechanism-based inhibitors of CYP3A4. Of the furanocoumarins investigated, furanocoumarin dimers, GF-I-1 and GF-I-4, were the most potent inhibitors of CYP3A4. Inhibitor concentration required for half-maximal rate of inactivation (KI) values for bergamottin, DHB, GF-I-1, and GF-I-4 were calculated, respectively, as 40.00, 5.56, 0.31, and 0.13 μM, whereas similar values were observed on their inactivation rate constant at infinite concentration of inhibitor (kinact, 0.05–0.08 min−1). Apparent selectivity toward CYP3A4 does occur with the furanocoumarin dimers. In contrast, bergamottin showed rather stronger inhibitory effect on CYP1A2, CYP2C9, CYP2C19, and CYP2D6 than on CYP3A4. DHB inhibited CYP3A4 and CYP1A2 activities at nearly equivalent potencies. Among P450 forms investigated, CYP2E1 was the least sensitive to the inhibitory effect of furanocoumarin components. A sesquiterpene nootkatone has no significant effect on P450 activities investigated except for CYP2A6 and CYP2C19 (Ki = 0.8 and 0.5 μM, respectively).
Author Keywords: cytochromes P450-inhibition; drug–grapefruit juice interaction; furanocoumarins; CYP3A4
1 To whom correspondence should be addressed. Fax: 81-22-2176826. E-mail: [email protected].
TulsaTalons
Member
i read that it also increases the negative side effects of PHs as well, so maybe this isnt the best idea? has anyone drank GFJ while taking h drol?
ryansm
Well-known member
It increases the efficacy of the drug (hormone) period, so if you take the same dose as you would without obviously you will have more sides. The benefit here at least to me is the ability to use less and get the same results.
kanakafarian
Well-known member
It's a potentiator for MANY drugs/meds out there. I drink it every single day pre-workout with ECA. On/off cycle, it doesn't matter, I drink it religiously.
soontobbeast
Well-known member
my response on the matter, from another thread :
it is extremely dangerous to start trying to amplify absorption of roids.
ESPECIALLY with methyls.
how do you know how much you are increasing it?
you dont.
while it may sound like an awesome idea to save money, since no one knows how much naringin ( the active constituent that increases absorption, which is an MAOI, FYI) amplifies absorption, you're *hopefully* not overdoing it.
that being said, don't give the thumbs up that its all benefit and no risk . some people take posts on AM very seriously without researching them.
kanakafarian
Well-known member
I've been at it for well over 12+ years along with clen/cyt/etc. with no ill effects. But that's me and I don't run dosages of anything high. Heck, even LMG I cap at 75mg and get outstanding results. Of course everyone varies so to each their own.
TulsaTalons
Member
pillsRgood
Active member
I combined GF juice with M1T back in the day, bad idea... It worked, but also led me to piss blood... def increased the strength of the drug... Its like putting nitro on a ferarri, seems like an awesome idea, till you hit 200 mph before a hairpin turn...
Evil Eagle
New member
Agreed. I have started mixing it with vanilla protein, it's so nasty by itself!
Sent from my Android device
Sent from my Android device