Acetylglucosaminidase, β-

Endpoint summary

Description of key information

Beta-N-acetylhexosaminidase was not tested for acute toxicity, but two closely-related enzymes, xylanase and alpha amylase, have been tested for acute toxicity.

The acute toxicity of xylanase and alpha amylase was tested by administration by gavage as a single oral dose to a group of rats followed by an observation period of 14 days. No signs of toxicity were observed among the rats treated with a single oral dose of xylanase corresponding to 2536 mg enzyme concentrate dry matter/kg bodyweight (equivalent to 652 mg aep/kg bodyweight) or a single dose of alpha amylase corresponding 2562 mg enzyme concentrate dry matter/kg bodyweight (equivalent to 859 mg aep/kg bodyweight).

Based on the similarity of the tested enzymes with beta-N-acetylhexosaminidase - all belonging to the same enzyme sub-subclass - it can be concluded that similar results are expected for beta-N-acetylhexosaminidase.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

June 04 - August 13, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Read-across to xylanase is applied. Data on xylanase are considered also to be valid for beta-N-acetylhexosaminidase, because both enzymes belong to the same enzyme sub-subclass IUB 3.2.1 and are considered to have a similar toxicological profile also with regard to acute toxicity.

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

Adopted 2001

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: In-house bred animals
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 10 weeks
- Weight at study initiation: 189.64 - 203.03 g
- Fasting period before study: The animals were not fasted prior to dose administration
- Housing: Three animals were housed in a standard Polysulfone cage (size: L 430 x B 285 x H; 200 mm) with stainless steel mesh top grill. Clean sterilized paddy husk was provided as bedding material. Sterilized paper shreds were provided as nesting material for enrichment.
- Diet (e.g. ad libitum): Nutrilab rodent feed (Manufactured by Provimi Animal Nutrition India Pvt Ltd.) ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 7-9 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.6 to 22.4°C
- Humidity (%): 50 to 64%
- Air changes (per hr): 12 to 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 22 June 2015 To: 15 July 2015

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Undiluted test material

Doses:

The animals were given two dosages of 10.3 mL/kg body weight with an interval of 4 hours between each administration (equivalent to 2536 mg enzyme concentrate dry matter/kg bodyweight or 652 mg aep/kg bodyweight)

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observation for clinical signs of toxicity and mortality at 30 to 40 min, 1 hr (±10 min), 2 hrs (±10 min), 3 hrs (±10 min) and 4 hrs (±10 min) after each administration on Day 1 and thereafter, once daily for clinical signs of toxicity and twice daily for mortality during the 14 days observation period. Individual animal body weight was recorded on Day 1 (before test item administration for first time), Day 7 and Day 14 during the observation period.
- Necropsy of survivors performed: yes

Statistics:

No

Sex:

female

Dose descriptor:

other: Fixed dose method - no effects were seen

Effect level:

> 20.6 mL/kg bw

Based on:

test mat.

Key result

Sex:

female

Dose descriptor:

other: Fixed dose method - no effects were seen

Effect level:

> 2 536 mg/kg bw

Based on:

other: Enzyme concentrate dry matter

Mortality:

No animals died during the study.

Clinical signs:

No clinical signs of toxicity and mortality were observed during the 14 days observation period.

Body weight:

No effect was observed on the body weights.

Gross pathology:

Effects on organs:
No gross pathological changes observed

Interpretation of results:

GHS criteria not met

Conclusions:

No signs of toxicity were observed among the rats treated with a single oral dose of 2536 mg enzyme concentrate dry matter/kg (equivalent to 652 mg aep/kg body weight), which was the highest possible dose at dose volume 20.6 mL/kg, using the undiluted test item.

Executive summary:

The objective of this study was to assess the acute toxicity of Xylanase when administered as a single oral dose to six rats followed by an observation period of 14 days. The purpose of the study was to satisfy regulatory demands because the enzyme is used for production of food in China.

The study was conducted in accordance with the OECD Guideline No 423, “Acute Oral Toxicity – Acute Toxic Class method”. The design of the limit test was used. The test item was supplied as a brown liquid ready to use. The dose volume administered was 20.6 mL/kg body weight corresponding 2536 mg enzyme concentrate dry matter/kg body weight or 652 mg aep/kg body weight.

No mortality or clinical signs were observed after treatment and the overall body weight gain during the study was considered to be normal. The necropsy revealed no abnormalities.

In conclusion, no signs of toxicity were observed among the rats treated with a single oral dose of 2536 mg enzyme concentrate dry matter/kg bodyweight, which was the highest possible dose at dose volume 20.6 mL/kg, using the undiluted test item.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

June 29 to August 31, 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Read-across to alpha amylase is applied. Data on alpha amylase are considered also to be valid for beta-N-acetylhexosaminidase, because both enzymes belong to the same enzyme sub-subclass IUB 3.2.1 and are considered to have a similar toxicological profile also with regard to acute toxicity.

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

Dec. 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

- Source: Charles River, Germany
- Fasting period before dosing: Overnight
- Housing: A maximum of 6 animals per sex per cage, transparent macrolon cages
- Weight at time of dosing: between 168-174 g
- Housing: In animal room with control of temperature and humidity
- Diet: Standard diet ad libitum
- Water: Tap water ad libitum
- Acclimatization period: 5 days
- Temperature (°C): 20-24°C
- Humidity : 45-70 %

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 20 mL/kg

Doses:

Undiluted test material 20 mL/kg body weight, equivalent to 2562 mg enzyme concentrate dry matter/kg body weight or 859 mg aep/kg body weight (limit testing).

No. of animals per sex per dose:

6 (only females)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations for clinical signs of effect: within 1 hour and within 4 hours after dosing and at least once daily throughout the observation period. Weighing: just prior to dosing on day 0 and on days 3, 7 and 14
- Necropsy of survivors performed: yes

Key result

Sex:

female

Dose descriptor:

LD0

Effect level:

2 562 mg/kg bw

Based on:

other: Enzyme concentrate dry matter

Sex:

female

Dose descriptor:

other: Limit test - no effects were seen

Effect level:

> 20 mL/kg bw

Based on:

test mat.

Mortality:

No mortality.

Clinical signs:

No clinical signs.

Body weight:

Body weights and body weight gains normal.

Gross pathology:

No abnormalities.

Interpretation of results:

GHS criteria not met

Conclusions:

No signs of toxicity were observed among the rats treated with a single oral dose of 2562 mg enzyme concentrate dry matter/kg bodyweight (equivalent to 859 mg aep/kg bodyweight), which was the highest possible dose at dose volume 20 mL/kg, using the undiluted test item.

Executive summary:

The objective of this study was to assess the acute toxicity of alpha-amylase when administered as a single oral dose to rats followed by an observation period of 14 days. The purpose of the study was to satisfy regulatory demands because the enzyme is used for production of food in EU.

The study was conducted in accordance with the OECD Guideline No 423, “Acute Oral Toxicity – Acute Toxic Class method”. The design of the limit test was used. The test item was supplied as a brown liquid ready to use. The dose volume administered was 20 mL/kg body weight corresponding to a dose of 2562 mg enzyme concentrate dry matter/kg body weight (equivalent to 859 mg aep/kg body weight). This was the highest possible dose level at dose volume 20 mL/kg body weight, using the undiluted test item.

No mortality or clinical signs were observed after treatment and the overall body weight gain during the study was considered to be normal. The necropsy revealed no abnormalities.

In conclusion, no signs of toxicity were observed among the rats treated with a single oral dose of 2562 mg enzyme concentrate dry matter/kg body weight, which was the highest possible dose at dose volume 20 mL/kg, using the undiluted test item.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

Toxicological data has been generated within the enzyme producing industry during the last 40 years. Substantial documentation on the safety of the production strains have been generated, and the enzyme test materials are thoroughly characterized. High quality studies for all relevant endpoints, in vivo studies as well as in vitro studies, show that industrial enzymes from well-known and well-characterized production strains have very similar safety profiles across the catalytic activities. Read-across can therefore be applied for the majority of toxicological endpoints. The database can thus be considered of high quality.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the results from the two acute toxicity tests with alpha amylase and xylanase, beta-N-acetylhexosaminidase is not classified.