Bcl-xL (Ki = 0.5-0.6 μM); Bcl-2 (Ki = 0.2-0.3 mM)

Gossypol, a naturally occurring substance extracted from cottonseeds and roots, has been investigated as a potential anticancer agent. Several clinical trials have examined the racemic form of Gossypol [(±)-Gossypol], which is well tolerated. The racemic form of Gossypol ((±)-Gossypol) has a Ki of 0.5 to 0.6 μM when it binds to the Bcl-xL protein. Additionally, (±)-Gossypol has a strong affinity for the Bcl-2 protein, with a Ki value of 0.2–0.3 mM. The (-)-Gossypol and (+)-Gossypol enantiomers are both present in the naturally occurring racemic Gossypol. In 6-day MTT assays, Gossypol's racemic form and each of its enantiomers are evaluated against UM-SCC-6 and UM-SCC-14A. In both of the tested cell lines, (-)-Gossypol exhibits a greater growth inhibition compared to (±)-Gossypol than (+)-Gossypol (P 0.001). With (±)-Gossypol, an intermediate growth inhibitory effect is seen, but only at the higher dose of Gossypol (10 μM, P<0.0001)[1].

In a 6-day MTT cell survival assay, two representative UM-SCC cell lines, UM-SCC-6 and UM-SCC-14A, are continuously exposed to 0, 5, or 10 μM of (±)-Gossypol, (-)-Gossypol, or (+)-Gossypol[1].

Absorption, Distribution and Excretion
Fat-soluble gossypol is readily absorbed from the gastrointestinal tract. It is highly bound to amino acids (especially lysine) and dietary iron. Gossypol's binding, metabolism, and urinary excretion are limited; most is excreted in feces.

Toxicity Summary
Gossypol may induce apoptosis by modulating Bax and Bcl-2 proteins. It is also an inhibitor of calcineurin and protein kinase C and has been shown to bind to calmodulin. (L1239) Interactions …This study used roosters (n = 144) from different humoral immune selection strains. Three individuals from each strain were randomly selected and placed in cages and fed a corn-soybean meal (control) diet for 14 days. Then, six cages from each strain were randomly selected and given four different dietary treatments (1000 mg/kg gossypol, 1000 mg/kg silymarin, a mixture of 1000 mg/kg gossypol and silymarin, or a control diet). Body weight and feed intake data were collected for 21 consecutive days, and blood was collected weekly to collect plasma and determine hematocrit. The chickens were then euthanized, and livers were collected for histological and enzyme activity analysis. Weekly endpoints were analyzed using repeated measures and regression analysis. Plasma and liver enzyme activities, as well as histological parameters, were analyzed using analysis of variance (ANOVA). No significant interactions were observed between diets and strains. Chickens fed gossypol and gossypol-silymarin diets ceased gaining weight on day 14 (P < 0.001) and experienced weight loss on day 21 (P < 0.001). These chickens also showed elevated γ-glutamyltransferase levels on day 14; by day 21, their activity further increased (P < 0.001). Histological examination of liver sections revealed significant fatty degeneration (P < 0.001). Furthermore, quinone reductase activities were significantly higher in chickens treated with gossypol and the combined gossypol-silymarin diet compared to the control and silymarin-treated groups (P < 0.001). Silymarin did not alleviate any clinical symptoms of gossypol poisoning.

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Non-human toxicity values
Oral LD50 in rats: 2315 mg/kg
Oral LD50 in pigs: 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.

Therapeutic Uses
/Experimental Therapy/ Gossypol (C(30)H(30)O(8)) is a polyphenolic compound derived from the cotton plant (Malvaceae family, Gossypium genus). The gossypol molecule contains six phenolic hydroxyl groups and two aldehyde groups, giving it high chemical activity. Gossypol can undergo Schiff base formation, ozone decomposition, oxidation, and methylation reactions to generate various gossypol derivatives. Due to the diverse biological activities of gossypol and its derivatives, including antifertility, antiviral, anticancer, antioxidant, antitrypanosomiasis, antibacterial, and antimalarial activities, it has been a focus of numerous studies. Because the rotation of the naphthalene ring interphase is restricted, gossypol is a chiral compound with two transisomers (i.e., (+)-gossypol and (-)-gossypol), which exhibit different biological activities. Gossypol is a small-molecule Bcl-2 family pro-survival protein inhibitor and has been shown to inhibit the growth of AI prostate cancer. However, in a mouse model of prostate cancer xenograft (vertebral prostate cancer [VCaP]) treated with AT-101 (R-(-)-gossypol acetate), the presence of androgens attenuated the apoptotic effects of gossypol. This study aimed to better understand the in vitro effects of the androgen receptor (AR) on AT-101-induced apoptosis. VCaP cells treated with AT-101 exhibited increased apoptosis and downregulated expression of the pro-survival protein Bcl-2. Combined treatment with AR activation and AT-101 reduced apoptosis, increased cell survival, and attenuated caspase activation. AT-101 downregulated the expression of Akt and the apoptosis inhibitor X (XIAP), while AR stimulation restored the expression of these proteins. Combined treatment with bicalutamide and AT-101 increased apoptosis by reducing the expression of these pro-survival proteins. These data suggest that combined treatment with AT-101 and ADT may further delay the onset of AI disease, thereby prolonging progression-free survival in prostate cancer patients.
/Experimental Treatment/...A series of new and known gossypol bis-Schiff base analogs were synthesized, and their anticancer activity against HeLa, U87, and M85 cells was tested. Results showed that less active (+)-gossypol could be converted into more active derivatives through simple chemical modification. Many more potent compounds were found compared to (-)-gossypol, which may be promising anticancer drugs; some of these compounds showed superior activity against all three cancer cell lines compared to the anticancer drug cisplatin.../Gossypol Analogs/
/Experimental Treatment/ Twenty-seven patients with pathologically confirmed gliomas relapsed after radiotherapy were treated with gossypol 10 mg orally twice daily. Of these, 15 had glioblastoma, 11 had anaplastic astrocytoma, and 1 had recurrent low-grade glioma. Efficacy was assessed every 8 weeks using CT/MRI scans and clinical criteria, including dexamethasone requirements. Treatment continued until disease progression. Two patients achieved partial remission (PR); four patients remained stable for 8 weeks or longer. One patient maintained PR with improved KPS score for 78 weeks. Another patient achieved partial remission for 8 weeks. Toxicity was mild: two patients with prior extensive treatment experienced mild thrombocytopenia, five patients experienced hypokalemia, and three patients experienced grade 2 hepatotoxicity and peripheral edema. In this study, gossypol levels determined by high-performance liquid chromatography (HPLC) were not correlated with efficacy or toxicity. We conclude that gossypol is well tolerated and, although its efficacy is low in a population of patients with recurrent gliomas who have received extensive treatment and have a poor prognosis, it is measurable…
For more complete data on the therapeutic uses of gossypol (7 items in total), please visit the HSDB record page.

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Drug Warning
Following clinical trials conducted in China in the 1970s, gossypol was proposed for use as a male contraceptive. This review summarizes numerous formal animal toxicology studies on gossypol and the recovery of fertility in men after discontinuation of gossypol treatment. These studies prompted the World Health Organization (WHO) Special Programme for Research, Development and Research Training in Human Reproduction (HRP) to decide that gossypol is unsuitable as an anti-fertility drug. …Reports indicate that studies conducted in China have confirmed the effectiveness of gossypol as an anti-fertility drug for men. …Research by the International Organization for the Advancement of Chemical Sciences (IOCSD) showed that 40 out of 70 novel high-purity gossypol structural forms had no higher activity than pure gossypol. Experiments in Sprague-Dawley rats and cynomolgus monkeys confirmed that both (-) and (+) gossypol are too toxic for human contraception. Among the side effects associated with gossypol use, the most serious is hypokalemic paralysis, although the reported differences in incidence may be attributed to variations in dietary potassium intake across different regions and genetic susceptibility. On the other hand, two independent studies confirmed the findings regarding the risk of permanent infertility in healthy men of reproductive age, finding an irreversible infertility rate of 25%. Failure to recover after discontinuing gossypol may be related to prolonged treatment duration, high total dose of gossypol, small testicular volume, and elevated follicle-stimulating hormone (FSH) levels...

C30H30O8

518.5544

518.194

C, 69.49; H, 5.83; O, 24.68

303-45-7

Gossypol (acetic acid);12542-36-8;Gossypol-13C2

3503

Light yellow to yellow solid powder

1.4±0.1 g/cm3

707.9±55.0 °C at 760 mmHg

181-183ºC

395.9±28.0 °C

0.0±2.3 mmHg at 25°C

1.742

6.16

6

8

5

38

780

0

O([H])C1C2C(C([H])=O)=C(C(=C(C([H])(C([H])([H])[H])C([H])([H])[H])C=2C([H])=C(C([H])([H])[H])C=1C1=C(C2C(C([H])=O)=C(C(=C(C([H])(C([H])([H])[H])C([H])([H])[H])C=2C([H])=C1C([H])([H])[H])O[H])O[H])O[H])O[H])O[H]

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

Cottonseed Meal Toxin; Pogosin; Gossypol; BL-193; BL 193; BL193; NSC 624336; NSC 56817

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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

DMSO: 33.3~100 mg/mL (64.3~192.9 mM)
Ethanol: 8 mg/mL (~15.4 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.01 mM) (saturation unknown) in 10% DMSO + 40% PEG300 +5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 + to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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