Thaxtomim A (Ref: MBI-005)	Last updated: 23/08/2025
(Not known by any other names)

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Hazard alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.

Environmental fate	Ecotoxicity	Human health

GENERAL INFORMATION

Description	Microorganism based herbicide for the post-emergence control of troublesome weeds
Example pests controlled	Broadleaved weeds and sedges
Example applications	Wide variety of land uses; Rice
Efficacy & activity	-
Appearance and life cycle	-
Taxonomic classification	-

GB regulatory status

GB COPR regulatory status	Not approved
Date COPR inclusion expires	Not applicable
GB LERAP status	No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status	Not approved
Dossier rapporteur/co-rapporteur	Not applicable
Date EC 1107/2009 inclusion expires	Not applicable
EU Candidate for substitution (CfS)	Not applicable
Listed in EU database	No
Approved for use (✓) under EC 1107/2009 in the following EU Member States	ATAustria BEBelgium BGBulgaria CYCyprus CZCzech Republic DEGermany DKDenmark EEEstonia ELGreece                   ESSpain FIFinland FRFrance HRCroatia HUHungary IEIreland ITItaly LTLithuania LULuxembourg                   LVLatvia MTMalta NLNetherlands PLPoland PTPortugal RORomania SESweden SISlovenia SKSlovakia
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries	ISIceland NONorway

Additional information

Known to be also used in the following countries	USA

Chemical structure

Isomerism	Isomeric - substance has three stereoisomers
Chemical formula	C₂₂H₂₂N₄O₆
Canonical SMILES	CN1C(C(=O)N(C(C1=O)(CC2=CC(=CC=C2)O)O)C)CC3=CNC4=C3C(=CC=C4)[N+](=O)[O-]
Isomeric SMILES	CN1[C@H](C(=O)N([C@](C1=O)(CC2=CC(=CC=C2)O)O)C)CC3=CNC4=C3C(=CC=C4)[N+](=O)[O-]
International Chemical Identifier key (InChIKey)	QRDNJYNIEGRRKV-PGRDOPGGSA-N
International Chemical Identifier (InChI)	InChI=1S/C22H22N4O6/c1-24-18(10-14-12-23-16-7-4-8-17(19(14)16)26(31)32)20(28)25(2)22(30,21(24)29)11-13-5-3-6-15(27)9-13/h3-9,12,18,23,27,30H,10-11H2,1-2H3/t18-,22+/m0/s1
2D structure diagram/image available?	Yes

General status

Biopesticide type		Herbicide
Substance groups		Micro-organism derived substance; Peptide herbicide
Minimum active substance purity		-
Known relevant impurities		-
Substance origin		Natural
Mode of action		Selective, phytoxin, causes plant cell necrosis
Substance source		Derived from the gram positive soil bacterium Streptomyces bottropensis
Uses		Plant protection
Target pests		Broadleaved weeds and sedges
Target host		Wide variety of land uses; Rice
Farming system suitability		-
CAS RN		122380-18-1
EC number		-
CIPAC number		-
US EPA chemical code		-
PubChem CID		-
Molecular mass		438.43
PIN (Preferred Identification Name)		-
IUPAC name		(3R,6S)-3-hydroxy-3-[(3-hydroxyphenyl)methyl]-1,4-dimethyl-6-[(4-nitro-1H-indol-3-yl)methyl]-2,5-piperazinedione
CAS name		2,5-piperazinedione
Listed (✓) under		UK Poisons List Order 1972 Rotterdam Convention Montreal Protocol XNo The Poisons List Order 1972 XNo Rotterdam Convention XNo Montreal Protocol Stockholm Convention OSPAR EU Water Framework Directive XNo Stockholm Convention XNo OSPAR XNo EU Water Framework Directive
Relevant Environmental Water Quality Standards		-
Forever chemical		-
Highly Hazardous Pesticide (HHP)	Type I	-
	Type II	-
Other status information		-
Herbicide Resistance Class (HRAC MoA class)		None
Herbicide Resistance Class (WSSA MoA class)		-
Insecticide Resistance Class (IRAC MoA class)		Not applicable
Fungicide Resistance Class (FRAC MOA class)		Not applicable
Examples of recorded resistance		-
Physical state		Yellow powder
Related substances & organisms		3-decen-2-one

Commercial

Property	Value
Availability status	Current
Introduction & key dates	1989, first reported; 2012, introduced
Example manufacturers & suppliers of products using this active now or historically	Marrone Bio Innovations
Example products using this active	Opportune
Formulation and application details	-
Commercial production	Thaxtomin A is produced by certain Streptomyces species, notably Streptomyces scabiei, as a secondary metabolite and potent phytotoxin. Its biosynthesis involves non-ribosomal peptide synthetases (NRPSs), specifically TxtA and TxtB, which assemble the molecule from amino acid precursors. A key supporting protein, TxtH helps ensure proper folding and function of the NRPS enzymes. Production is typically carried out in specialised media like oatmeal broth, which enhances yield compared to standard nutrient broths. To improve commercial viability, scientists have engineered the thaxtomin A gene cluster into heterologous Streptomyces hosts and optimised promoter sequences to boost output.
Impact on climate of production and use	-

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C at pH 7 (mg l⁻¹)		-	-	-
Solubility - In organic solvents at 20 °C (mg l⁻¹)		Soluble	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Ethanol	-
		Soluble	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source DMSO	-
Melting point (°C)		310	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source	-
Boiling point (°C)		795	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	-	-	-
	Log P	-	-	-
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		1.48	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source	-
Dissociation constant pKa) at 25 °C		-	-	-
		-
Vapour pressure at 20 °C (mPa)		-	-	-
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		-	-	-
Volatilisation as max % of applied dose lost	From plant surface	-	-	-
	From soil surface	-	-	-
Maximum UV-vis absorption L mol⁻¹ cm⁻¹		-	-	-
Surface tension (mN m⁻¹)		-	-	-

Degradation

Property		Value	Source; quality score; and other information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT₅₀ (typical)	-	-	-
	DT₅₀ (lab at 20 °C)	-	-	-
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	-
Dissipation rate RL₅₀ (days) on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL₅₀ (days) on and in plant matrix	Value	-	-	-
	Note	-
Aqueous photolysis DT₅₀ (days) at pH 7	Value	-	-	-
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	-	-	-
	Note	-
Water-sediment DT₅₀ (days)		-	-	-
Water phase only DT₅₀ (days)		-	-	-
Sediment phase only DT₅₀ (days)		-	-	-
Air degradation		As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.
Decay in stored produce DT₅₀		-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd (mL g⁻¹)	-	-	-
	Koc (mL g⁻¹)	-
	Notes and range	-
Freundlich	Kf (mL g⁻¹)	-	-	-
	Kfoc (mL g⁻¹)	-
	1/n	-
	Notes and range	-
pH sensitivity		-

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		-	-	-
Mammals - Short term dietary NOEL	(mg kg⁻¹)	-	-	-
	(ppm diet)	-		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		-	-	-
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹ dw soil)		-	-	-
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹ dw soil)		-	-	-
Soil micro-organisms		-	-	-
Collembola	Acute LC₅₀ (mg kg⁻¹)	-	-	-
	Chronic NOEC (mg kg⁻¹)	-	-	-
Non-target plants	Vegetative vigour ER₅₀ (g ha⁻¹)	-	-	-
	Seedling emergence ER₅₀ (g ha⁻¹)	-	-	-
Honeybees (Apis spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Chronic	-	-	-
	Notes	-
Bumblebees (Bombus spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
Mason bees (Osmia spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
Other bee species (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other bee species (2)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Beneficial insects (Ladybirds)		-	-	-
Beneficial insects (Lacewings)		-	-	-
Beneficial insects (Parasitic wasps)		-	-	-
Beneficial insects (Predatory mites)		-	-	-
Beneficial insects (Ground beetles)		-	-	-

Aquatic ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		-	-	-
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		-	-	-
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)		-	-	-
Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)		-	-	-
Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)		-	-	-
Algae - Acute (growth rate, fresh; mg l⁻¹)		-	-	-
Algae - Chronic (growth rate, fresh; mg l⁻¹)		-	-	-
Mesocosm study data	NOEAEC mg l⁻¹	-	-	-
	NOEAEC mg l⁻¹	-	-	-
Marine bivalves		-	-	-

HUMAN HEALTH AND PROTECTION

General

Property		Value	Source; quality score; and other information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		-	-	-
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		-	-	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		-	-	-
Other Mammal toxicity endpoints		-	-	-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)		-	-	-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)		-	-	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)		-	-	-
Dermal penetration studies (%)		-	-	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Routes	Public	-
	Occupational	-
Mammalian dose elimination route and rate		-	-	-

Health issues

Specific human health issues (hazard-based)		Carcinogen Genotoxic Endocrine disruptor No data found A0 A = Chromosome aberration (EFSA database) 0 = No data ; B0 B = DNA damage/repair (EFSA database) 0 = No data ; C0 C = Gene mutation (EFSA database) 0 = No data ; D0 D = Genome mutation (EFSA database) 0 = No data ; E0 E = Unspecified genotoxicity type (miscellaneous data source) 0 = No data No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant No data found No data found No data found Respiratory tract irritant Skin irritant Skin sensitiser No data found No data found No data found Eye irritant Phototoxicant   No data found No data found
General human health issues		No information available

Handling issues

Property	Value and interpretation
General	No information available
CLP classification 2013	-
WHO Classification	Not listed (Not listed)
UN Number	-
Waste disposal & packaging	-
Shelf-life, storage, stability and reactivity	-

TRANSLATIONS

Language	Name
English	thaxtomim A
French	-
German	-
Danish	-
Italian	-
Spanish	-
Greek	-
Polish	-
Swedish	-
Hungarian	-
Dutch	-
Norwegian	-

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Record last updated:	23/08/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242