The two enantiomers of natural racemic gossypol are (+)-gossypol and (R)-(-)-gossypol (AT-101). The binding affinities of (R)-(-)-gossypol (AT-101) and (+)-gossypol to Bcl-2 or Bcl-xL are similar, although AT-101 is more efficient than (+)-gossypol. The effects of serum in cell culture tests may be the cause of the inhibition of cell growth and activation of apoptosis. In a 6-day MTT experiment, the racemic form of gossypol and each enantiomer were evaluated against UM-SCC-6 and UM-SCC-14A. Between the two cell lines examined, AT-101 showed a higher degree of growth inhibition in comparison to (±)-gossypol as opposed to (+)-gossypol (P<0.001). (±)-gossypol was shown to exhibit moderate growth inhibition; however, this impact was only seen at higher gossypol dosages (10 μM, P<0.0001). (R)-(-)-Gossypol (AT-101) possesses strong anti-head and neck squamous cell carcinoma (HNSCC) cell line activity in vitro and binds to the BH3 binding groove of the Bcl-xL and Bcl-2 proteins with a comparatively high affinity. Furthermore, it has the ability to effectively trigger programmed cell death in HNSCC tumor cells that express functional p53 and eliminate tumor cells that express mutant p53 via distinct processes. When compared to HNSCC cell lines, the amount of AT-101 needed to 50% suppress the development of human fibroblast cell lines was two to ten times more. (R)-(-)-gossypol (AT-101) concentrations were two to three times greater than in HNSCC cell lines in order to 50% decrease human oral keratinocyte development. In a 6-day MTT experiment, 10 UM-SCC cell lines showed a dose-dependent reduction of cell growth in the 0.5 to 10 μM range when treated with (R)-(-)-Gossypol (AT-101). Cell lines exhibit varying degrees of sensitivity; highly sensitive groups have IC50s between 2 and 5 μM, whilst less sensitive groups have IC50s centered around 10 μM [1]. It has been established that (R)-(-)-Gossypol (AT-101) binds to the proteins Bcl-2, Mcl-1, and Bcl-xL, with Ki values of 260±30 nM, 170±10 nM, and 480±40 nM, respectively [2].

Absorption, Distribution and Excretion
Lipid-soluble gossypol is readily absorbed from the GI tract. It is highly protein-bound to amino acids, especially lysine, and to dietary iron. Conjugation, metabolism, and urinary excretion of gossypol is limited; most is eliminated in the feces.

Toxicity Summary
Gossypol may cause apoptosis via the regulation of Bax and Bcl-2 proteins. It is also an inhibitor of calcineurin and protein kinases C, and has been shown to bind calmodulin. (L1239)

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Interactions
... Cockerels (n = 144) from lines divergently selected for humoral immunity were used. Three individuals from each line were randomly assigned to a cage and fed a corn-soybean meal (control) diet for 14 d. Six cages per line were then randomly assigned 1 of 4 dietary treatments (1,000 mg/kg of gossypol, 1,000 mg/kg of silymarin, 1,000 mg/kg of both gossypol and silymarin, or a control diet). Body weight and feed intake data were collected for 21 d, with chickens bled weekly to collect plasma and determine hematocrits. Chickens were then killed, and livers were collected for subsequent histology and enzymatic activity analyses. Endpoints measured weekly were analyzed with repeated measures and regression methodologies. Plasma and liver enzyme activities, and histological measures, were analyzed using ANOVA. No significant interactions between diets and lines were observed. Chickens assigned to the gossypol and gossypol-silymarin diets stopped gaining weight at d 14 (P < 0.001) and lost weight by d 21 (P < 0.001). Gamma glutamyltransferase was also elevated in these chickens at d 14; activities increased further by d 21 (P < 0.001). Histological examination of liver slices indicated substantial lipidosis (P < 0.001). Furthermore, quinone reductase activity was higher in gossypol- and gossypol-silymarin-treated chickens than in control and silymarin-treated chickens (P < 0.001). Silymarin did not alleviate any clinical effects of gossypol toxicosis.

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Non-Human Toxicity Values
LD50 Rat oral 2315 mg/kg
LD50 Pig oral 550 mg/kg

[1]. In vitro effects of the BH3 mimetic, (-)-Gossypol, on head and neck squamous cell carcinoma cells. Clin Cancer Res. 2004 Nov 15;10(22):7757-63.

[2]. Apogossypolone, a nonpeptidic small molecule inhibitor targeting Bcl-2 family proteins, effectively inhibits growth of diffuse large cell lymphoma cells in vitro and in vivo. Cancer Biol Ther. 2008 Sep;7(9):1418-26.

Therapeutic Uses
/Experimental Therapy/ Gossypol (C(30)H(30)O(8)) is a polyphenolic compound derived from the cotton plant (genus Gossypium, family Malvaceae). The presence of six phenolic hydroxyl groups and two aldehydic groups makes gossypol chemically reactive. Gossypol can undergo Schiff base formation, ozonolysis, oxidation, and methylation to form gossypol derivatives. Gossypol and its derivatives have been the target of much research due to their multifaceted biological activities including antifertility, antivirus, anticancer, antioxidant, antitrypanosomal, antimicrobial, and antimalarial activities. Because of restricted rotation of the internaphthyl bond, gossypol is a chiral compound, which has two atropisomers (i.e., (+)- and (-)-gossypol) that exhibit different levels of biological activities.
/Experimental Therapy/ Gossypol, a small molecule inhibitor of pro-survival Bcl-2 family proteins, has been demonstrated to inhibit AI prostate cancer growth. The apoptotic effect of gossypol, however, has been demonstrated to be attenuated by the presence of androgen in a prostate cancer xenograft mouse model (Vertebral Cancer of Prostate [VCaP]) treated with AT-101 (R-(-)-gossypol acetic acid). This study was undertaken to better understand the in vitro effects of androgen receptor (AR) on AT-101-induced apoptosis. VCaP cells treated with AT-101 demonstrated an increase in apoptosis and downregulation of Bcl-2 pro-survival proteins. Upon AR activation in combination with AT-101 treatment, apoptosis is reduced, cell survival increases, and caspase activation is attenuated. Akt and X inhibitor of apoptosis (XIAP) are downregulated in the presence of AT-101, and AR stimulation rescues protein expression. Combination treatment of bicalutamide and AT-101 increases apoptosis by reducing the expression of these pro-survival proteins. These data suggest that combination therapy of AT-101 and ADT may further delay the onset of AI disease, resulting in prolonged progression-free survival of prostate cancer patients. .
/Experimental Therapy/ ... a series of new and known bis-Schiff base analogs of chiral gossypol were synthesized, and their anticancer activity on HeLa, U87 and M85 cells was tested. The results showed that through a simple chemical modification, less active (+)-gossypol could be converted into more active derivatives. When compared with (-)-gossypol, many more potent compounds that could be the promising anticancer agents were found, and some of them were more potent than the anticancer drug Cisplatin against all three cancer cell lines... /Gossypol analogs/
/Experimental Therapy/ Gossypol 10 mg PO bid /was administered in 27 patients with pathologically confirmed glial tumors which had recurred after radiation therapy. Fifteen patients had glioblastoma, 11 patients anaplastic astrocytoma, 1 patient relapsed low grade glioma. Response was assessed every 8 weeks using CT/MRI scan and clinical criteria including decadron requirement. Treatment was continued until disease progression. Two patients had partial response (PR); 4 had stable disease for 8 weeks or more. One patient maintained a PR with improved KPS for 78 weeks. The other had a PR lasting 8 weeks. Toxicity was mild: 2 heavily pretreated patients had mild thrombocytopenia, 5 patients developed hypokalemia, 3 patients developed grade 2 hepatic toxicity and peripheral edema. Gossypol levels measured by HPLC did not correlate with response or toxicity in this study. We conclude that gossypol is well tolerated and has a low, but measurable, response rate in a heavily pretreated, poor-prognosis group of patients with recurrent glioma...
For more Therapeutic Uses (Complete) data for Gossypol (7 total), please visit the HSDB record page.

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Drug Warnings
Following clinical trials conducted in China in the 1970s, gossypol was proposed as a drug for male contraceptive use. This review summarizes the extensive investigations on formal animal toxicology and on the recovery of fertility in men after stopping gossypol treatment which led to the decision by the Special Programme of Research, Development and Research Training in Human Reproduction (HRP) at the World Health Organization (WHO), that gossypol would not be acceptable as an antifertility drug. ... There have been reports that studies conducted in China confirm the efficacy of gossypol as a male antifertility drug. ... Studies conducted by the International Organization for Chemical Sciences in Development showed that 40 of the 70 highly purified, novel structural forms of gossypol were no more active than gossypol. Experiments conducted on Sprague-Dawley rats and cynomolgous monkeys confirm that either (-) or (+) gossypol is too toxic to be developed for human contraception. Among the side effects associated with the use of gossypol, the most serious was hypokalemic paralysis, although differences in reported incidences could be attributed to the regional differences in dietary intake of potassium and genetic predisposition. On the other hand, studies that examine the risk of permanent sterility among healthy reproductive males were confirmed by two separate studies, which found an incidence of 25% irreversible sterility. The failure of recovery among those who stopped gossypol use could be attributed to longer treatment, greater total dose of gossypol, smaller testicular volume, and elevated follicle stimulating hormone concentrations...

C₃₀H₃₀O₈

518.5544

518.194

90141-22-3

(R)-(-)-Gossypol acetic acid;866541-93-7;(S)-Gossypol (acetic acid);1189561-66-7;Gossypol (acetic acid);12542-36-8

3503

Light yellow to yellow solid powder

1.4±0.1 g/cm3

707.9±55.0 °C at 760 mmHg

166-167ºC

395.9±28.0 °C

0.0±2.3 mmHg at 25°C

1.742

6.16

6

8

5

38

780

0

QBKSWRVVCFFDOT-UHFFFAOYSA-N

InChI=1S/C30H30O8/c1-11(2)19-15-7-13(5)21(27(35)23(15)17(9-31)25(33)29(19)37)22-14(6)8-16-20(12(3)4)30(38)26(34)18(10-32)24(16)28(22)36/h7-12,33-38H,1-6H3

7-(8-formyl-1,6,7-trihydroxy-3-methyl-5-propan-2-ylnaphthalen-2-yl)-2,3,8-trihydroxy-6-methyl-4-propan-2-ylnaphthalene-1-carbaldehyde

AT101AT 101AT-101R-(-)-gossypol acetic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)