Food & Drink / Compounds / Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole)

Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole) in food: ingestion safety

Moderate risk

Dietary Trp-P-2 ingestion is concentrated in charred meat surfaces and heavily pyrolyzed protein food products — the same food matrices that yield Glu-P-1, Glu-P-2, and AαC from other high-temperature amino acid pyrolysis pathways. Trp-P-2 was isolated from the mutagenic fraction of tryptophan pyrolysate and from beef extract in the same 1970s Japanese research program that identified the broader HCA class, establishing it as one of the founding compounds in HCA food safety science. Trp-P-2 concentrations in charred meat surfaces are typically 0.1–2 ng/g; in non-charred conventionally cooked meat, Trp-P-2 is below detection limits by standard analytical methods (LC-MS/MS, HPLC with fluorescence detection). Trp-P-2 is metabolically activated more efficiently by CYP1A1 (expressed in extrahepatic tissues including lung and colon) than by hepatic CYP1A2 in some experimental systems, suggesting potential relevance for extrahepatic tissue genotoxicity alongside its well-established hepatocarcinogenicity. The co-occurrence of Trp-P-2 with Trp-P-1 (the 4-methyl analog), Glu-P-1, Glu-P-2, AαC, and PAHs in charred food surfaces means that consumers of charred meat receive all these pyrolysis carcinogens simultaneously as a complex mixture, and risk assessment that addresses only individual compounds underestimates the total carcinogenic burden from charred food consumption. Practical risk reduction strategy: remove charred portions before eating, select lower-temperature cooking methods, and avoid direct-flame charcoal grilling at temperatures that produce visible charring — interventions that simultaneously eliminate all pyrolysis HCA exposure.

What is trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole)?

The IUPAC name is 1-methyl-5H-pyrido[4,3-b]indol-3-amine.

Also known as: 1-methyl-5H-pyrido[4,3-b]indol-3-amine, Trp-P-2, 3-Amino-1-methyl-5H-pyrido[4,3-b]indole, Tryptophan-P-2.

IUPAC name
1-methyl-5H-pyrido[4,3-b]indol-3-amine
CAS number
62450-07-1
Molecular formula
C12H11N3
Molecular weight
197.24 g/mol
SMILES
CC1=C2C3=CC=CC=C3NC2=CC(=N1)N
PubChem CID
5284476

Risk for people

Moderate risk

Dietary Trp-P-2 ingestion is concentrated in charred meat surfaces and heavily pyrolyzed protein food products — the same food matrices that yield Glu-P-1, Glu-P-2, and AαC from other high-temperature amino acid pyrolysis pathways. Trp-P-2 was isolated from the mutagenic fraction of tryptophan pyrolysate and from beef extract in the same 1970s Japanese research program that identified the broader HCA class, establishing it as one of the founding compounds in HCA food safety science. Trp-P-2 concentrations in charred meat surfaces are typically 0.1–2 ng/g; in non-charred conventionally cooked meat, Trp-P-2 is below detection limits by standard analytical methods (LC-MS/MS, HPLC with fluorescence detection). Trp-P-2 is metabolically activated more efficiently by CYP1A1 (expressed in extrahepatic tissues including lung and colon) than by hepatic CYP1A2 in some experimental systems, suggesting potential relevance for extrahepatic tissue genotoxicity alongside its well-established hepatocarcinogenicity. The co-occurrence of Trp-P-2 with Trp-P-1 (the 4-methyl analog), Glu-P-1, Glu-P-2, AαC, and PAHs in charred food surfaces means that consumers of charred meat receive all these pyrolysis carcinogens simultaneously as a complex mixture, and risk assessment that addresses only individual compounds underestimates the total carcinogenic burden from charred food consumption. Practical risk reduction strategy: remove charred portions before eating, select lower-temperature cooking methods, and avoid direct-flame charcoal grilling at temperatures that produce visible charring — interventions that simultaneously eliminate all pyrolysis HCA exposure.

Regulatory consensus

4 regulatory and scientific bodies have classified Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole). The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / IARC—Group 2B - Possibly carcinogenic to humans
EPA CTX / CalEPA—Known human carcinogen
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 11 positive / 0 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 11 positive / 0 negative reports)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole)

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Food — processed food, beverages, candy, baked goods

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole):

  • Natural preservatives; Clean-label ingredients; Minimally processed food
    Trade-offs: Consumer label appeal ('clean label'); variable efficacy depending on food matrix and target pathogen; may alter flavor/color; regulatory status varies by jurisdiction; often more expensive per unit of preservation effect.
    Relative cost: 2-5× conventional

Frequently asked questions

Is trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole) safe for you?

Dietary Trp-P-2 ingestion is concentrated in charred meat surfaces and heavily pyrolyzed protein food products — the same food matrices that yield Glu-P-1, Glu-P-2, and AαC from other high-temperature amino acid pyrolysis pathways. Trp-P-2 was isolated from the mutagenic fraction of tryptophan pyrolysate and from beef extract in the same 1970s Japanese research program that identified the broader HCA class, establishing it as one of the founding compounds in HCA food safety science. Trp-P-2 concentrations in charred meat surfaces are typically 0.1–2 ng/g; in non-charred conventionally cooked meat, Trp-P-2 is below detection limits by standard analytical methods (LC-MS/MS, HPLC with fluorescence detection). Trp-P-2 is metabolically activated more efficiently by CYP1A1 (expressed in extrahepatic tissues including lung and colon) than by hepatic CYP1A2 in some experimental systems, suggesting potential relevance for extrahepatic tissue genotoxicity alongside its well-established hepatocarcinogenicity. The co-occurrence of Trp-P-2 with Trp-P-1 (the 4-methyl analog), Glu-P-1, Glu-P-2, AαC, and PAHs in charred food surfaces means that consumers of charred meat receive all these pyrolysis carcinogens simultaneously as a complex mixture, and risk assessment that addresses only individual compounds underestimates the total carcinogenic burden from charred food consumption. Practical risk reduction strategy: remove charred portions before eating, select lower-temperature cooking methods, and avoid direct-flame charcoal grilling at temperatures that produce visible charring — interventions that simultaneously eliminate all pyrolysis HCA exposure.

What products contain trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole)?

Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); processed food (Food).

Why do regulators disagree about trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole)?

Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole) has been classified by 4 agencies including EPA CTX / IARC, EPA CTX / CalEPA, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole) in the food app

Look up products containing trp-p-2 (3-amino-1-methyl-5h-pyrido[4,3-b]indole), compare to alternatives, and explore the full data record.

Open in food View raw API data

Sources (2)
  1. IARC Monographs Volume 56: Some Naturally Occurring Substances: Food Items and Constituents, Heterocyclic Aromatic Amines and Mycotoxins — IQ Group 2A; PhIP Group 2B, MeIQx Group 2B, MeIQ Group 2B, Glu-P-1 Group 2B, Glu-P-2 Group 2B, AαC Group 2B, Trp-P-2 Group 2B (1993) (1993) — regulatory
  2. EFSA Panel on Contaminants in the Food Chain (CONTAM): Scientific Opinion on the Risk for Human Health Related to the Presence of Heterocyclic Aromatic Amines (HAAs) in Food — PhIP, IQ, MeIQx, and related HCAs; Margin of Exposure approach; grilled and fried meat as primary exposure matrices (2021) (2021) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →