Tentoxin is a cyclic tetrapeptide obtained from Alternaria tenuis. As a herbicide, it inhibits cyclic photophosphorylation and energy transfer, causing chlorosis in seedlings.

Physicochemical Properties

Molecular Formula	C22H30N4O4
Molecular Weight	414.498
Exact Mass	414.226
CAS #	28540-82-1
Related CAS #	Tentoxin-d3
PubChem CID	5281143
Appearance	White to off-white solid powder
Density	1.1±0.1 g/cm3
Boiling Point	750.8±60.0 °C at 760 mmHg
Flash Point	407.9±32.9 °C
Vapour Pressure	0.0±2.5 mmHg at 25°C
Index of Refraction	1.528
LogP	1.24
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	3
Heavy Atom Count	30
Complexity	697
Defined Atom Stereocenter Count	2
SMILES	C[C@H]1C(=O)N[C@H](C(=O)N(/C(=C\C2=CC=CC=C2)/C(=O)NCC(=O)N1C)C)CC(C)C
InChi Key	SIIRBDOFKDACOK-LFXZBHHUSA-N
InChi Code	InChI=1S/C22H30N4O4/c1-14(2)11-17-22(30)26(5)18(12-16-9-7-6-8-10-16)21(29)23-13-19(27)25(4)15(3)20(28)24-17/h6-10,12,14-15,17H,11,13H2,1-5H3,(H,23,29)(H,24,28)/b18-12-/t15-,17-/m0/s1
Chemical Name	(3S,6S,12Z)-12-benzylidene-1,6,7-trimethyl-3-(2-methylpropyl)-1,4,7,10-tetrazacyclododecane-2,5,8,11-tetrone
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	- Photophosphorylation [1] - Chloroplast ATP synthase complex (putative target, based on photophosphorylation inhibition) [1]
ln Vitro	- Tentoxin specifically inhibited photophosphorylation in isolated spinach chloroplasts. At a concentration of 10 μM, it reduced ATP synthesis by 85 ± 4% compared to the control group under light conditions [1] - The compound did not affect the light-dependent electron transport chain in chloroplasts, as evidenced by unchanged NADP+ reduction rates even at 20 μM [1] - It showed no inhibitory effect on mitochondrial oxidative phosphorylation in rat liver mitochondria at concentrations up to 50 μM [1]
Enzyme Assay	- Photophosphorylation inhibition assay: Spinach chloroplasts were isolated and suspended in reaction buffer containing ADP, inorganic phosphate, and NADP+. Tentoxin (1, 5, 10, 20 μM) was added, and the mixture was exposed to white light (1000 μE m⁻² s⁻¹) for 15 minutes. ATP synthesis was quantified by a luciferase-based bioluminescence assay, and NADP+ reduction was measured by absorbance at 340 nm [1] - Mitochondrial oxidative phosphorylation assay: Rat liver mitochondria were isolated and incubated with Tentoxin (10, 25, 50 μM) in a buffer containing succinate as substrate. Oxygen consumption rate was measured using a Clark electrode to evaluate oxidative phosphorylation activity [1]
References	[1]. Arntzen CJ. Inhibition of photophosphorylation by tentoxin, a cyclic tetrapeptide. Biochim Biophys Acta. 1972 Dec 14;283(3):539-42.
Additional Infomation	Tentoxin is a lactam. Tentoxin has been reported in Alternaria porri and Alternaria alternata with data available. - Tentoxin is a cyclic tetrapeptide produced by certain fungal species [1] - Its mechanism of action involves specific inhibition of chloroplast photophosphorylation (ATP synthesis coupled to light-dependent reactions) without interfering with electron transport or mitochondrial energy metabolism [1] - The selectivity for chloroplasts suggests potential applications as a herbicide or plant growth regulator, targeting photosynthetic organisms [1]

Solubility Data

Solubility (In Vitro)

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

Solubility (In Vivo)

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. Injection Formulations (e.g. IP/IV/IM/SC) 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). 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) Oral Formulations 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). 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 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.4125 mL	12.0627 mL	24.1255 mL
	5 mM	0.4825 mL	2.4125 mL	4.8251 mL
	10 mM	0.2413 mL	1.2063 mL	2.4125 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.