Citric Acid

Citric acid is a weak organic tricarboxylic acid found in citrus fruits. Citric acid is a natural preservative and food tartness enhancer.

Signaling Pathways >> Apoptosis >> Apoptosis

Research Areas >> Inflammation/Immunology

Natural Products >> Acids and Aldehydes

Research Areas >> Cancer

Research Areas >> Cardiovascular Disease

Research Areas >> Metabolic Disease

Human Endogenous Metabolite

Citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. It inhibits proliferation of HaCaT cells in a dose-dependent manner, but also induces apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h)[1].

Citric acid is found in all animal tissues as an intermediary substance in oxidative metabolism. The administration of citric acid (1–2 g/kg) attenuates LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite is decreased by 1 g/kg citric acid. Citric acid (1-2 g/kg) decreases brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation[2]. Citric acid supplementation increases intestinal calcium and phosphorus absorption and the retention/intake ratio only in rats fed the 1% Ca diet. Citric acidsupplementation together with a calcium-rich diet allows to obtain an increased retention of calcium and phosphorus in bone. The prolonged administration of calcium citrate supplements may therefore help to increase bone mineral concentration[3]. Oral administration of citric acid ameliorates ketosis and protects against the development of diabetic complications in an animal model of type 1 diabetes[4].

HaCaT cells are treated with different concentrations of citric acid (2.5, 5, 7.5, 10, 12.5 mM) for 24 h; 0.5% of DMSO (vehicle) is used as a control. Cells are then centrifuged at 1000 ×g for 5 min, and cell pellets are dissolved with 0.5 mL of Phosphate buffered saline (PBS) containing 5 μg/mL PI and viable cells are determined by using a flow cytometer for determination of viable cells[1].

Rats: Rats are induced of diabetes and divided randomly into an untreated diabetic group and two treated diabetic groups, receiving citric acid (2 g/L) in the drinking water, or insulin therapy. Insulin-treated rats receive 3 IU of neutral protamine Hagedorn insulin three times per week. Fasting (12 hr) blood samples are obtained from the tail vein two days after insulin injection for measurement of blood glucose, HbA1c and ketone bodies[4]. [2]Mice: Citric acid is prepared in sterile physiological saline. Mice are randomly divided into five equal groups (six mice each). Mice are treated with either 0.2mL of: sterile physiological saline (group 1) or citric acid at doses of 1, 2, and 4 g/kg, orally (groups 2-4). Treatments are given just prior to endotoxin administration (LPS: 200 lg/kg, injected intraperitoneally, 0.1 mL). The fifth group received just the vehicle, no LPS (negative control). Mice are euthanized after 4 h of LPS or vehicle injection by decapitation under ether anesthesia, where the brain and liver of each mouse are then removed for analysis[2].

[1]. Ying TH, et al. Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways. Anticancer Res. 2013 Oct;33(10):4411-20.

[2]. Abdel-Salam OM, et al. Citric acid effects on brain and liver oxidative stress in lipopolysaccharide-treated mice. J Med Food. 2014 May;17(5):588-98.

[3]. Lacour B, et al. Stimulation by citric acid of calcium and phosphorus bioavailability in rats fed a calcium-rich diet. Miner Electrolyte Metab. 1997;23(2):79-87.

[4]. Nagai R, et al. Citric acid inhibits development of cataracts, proteinuria and ketosis in streptozotocin (type 1) diabetic rats. Biochem Biophys Res Commun. 2010 Feb 26;393(1):118-22.

3-Methyladenine | Hydrocortisone | Acetylcysteine(N-acetylcysteine) | Retinoic acid | Melatonine | Dinoprostone | Nicotinamide | Adenosine triphosphate | 4-Acetamidophenol | Prostaglandin E1 | Dehydroepiandrosterone | Corticosterone | Progesterone | Docosahexaenoic Acid | NAD+

DATA ITEMS CITED :

18

MOLECULAR FORMULA :

C6-H8-O7

MOLECULAR WEIGHT :

192.14

WISWESSER LINE NOTATION :

QV1XQVQ1VQ

HEALTH HAZARD DATA

ACUTE TOXICITY DATA

TYPE OF TEST :

Standard Draize test

ROUTE OF EXPOSURE :

Administration onto the skin

SPECIES OBSERVED :

Rodent - rabbit

REFERENCE :

85JCAE "Prehled Prumyslove Toxikologie; Organicke Latky," Marhold, J., Prague, Czechoslovakia, Avicenum, 1986 Volume(issue)/page/year: -,658,1986

TYPE OF TEST :

Standard Draize test

ROUTE OF EXPOSURE :

Administration into the eye

SPECIES OBSERVED :

Rodent - rabbit

REFERENCE :

85JCAE "Prehled Prumyslove Toxikologie; Organicke Latky," Marhold, J., Prague, Czechoslovakia, Avicenum, 1986 Volume(issue)/page/year: -,658,1986 ** ACUTE TOXICITY DATA **

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

3 gm/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

OYYAA2 Oyo Yakuri. Pharmacometrics. (Oyo Yakuri Kenkyukai, CPO Box 180, Sendai 980-91, Japan) V.1- 1967- Volume(issue)/page/year: 43,561,1992

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

290 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

TOVEFN Toksikologicheskii Vestnik. (18-20 Vadkovskii per. Moscow, 101479, Russia) History Unknown Volume(issue)/page/year: (5),9,1994

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Subcutaneous

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

5500 mg/kg

TOXIC EFFECTS :

Lungs, Thorax, or Respiration - other changes Musculoskeletal - other changes

REFERENCE :

TAKHAA Takeda Kenkyusho Ho. Journal of the Takeda Research Laboratories. (Takeda Yakuhin Kogyo K.K., 2-17-85 Jusohon-machi, Yodogawa-ku, Osaka 532, Japan) V.29- 1970- Volume(issue)/page/year: 30,25,1971

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

5040 mg/kg

TOXIC EFFECTS :

Lungs, Thorax, or Respiration - other changes Musculoskeletal - other changes

REFERENCE :

TAKHAA Takeda Kenkyusho Ho. Journal of the Takeda Research Laboratories. (Takeda Yakuhin Kogyo K.K., 2-17-85 Jusohon-machi, Yodogawa-ku, Osaka 532, Japan) V.29- 1970- Volume(issue)/page/year: 30,25,1971

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

903 mg/kg

TOXIC EFFECTS :

Details of toxic effects not reported other than lethal dose value

REFERENCE :

TXCYAC Toxicology. (Elsevier Scientific Pub. Ireland, Ltd., POB 85, Limerick, Ireland) V.1- 1973- Volume(issue)/page/year: 62,203,1990

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Subcutaneous

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

2700 mg/kg

TOXIC EFFECTS :

Lungs, Thorax, or Respiration - other changes Musculoskeletal - other changes

REFERENCE :

TAKHAA Takeda Kenkyusho Ho. Journal of the Takeda Research Laboratories. (Takeda Yakuhin Kogyo K.K., 2-17-85 Jusohon-machi, Yodogawa-ku, Osaka 532, Japan) V.29- 1970- Volume(issue)/page/year: 30,25,1971

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

42 mg/kg

TOXIC EFFECTS :

Behavioral - convulsions or effect on seizure threshold Lungs, Thorax, or Respiration - cyanosis Gastrointestinal - changes in structure or function of salivary glands

REFERENCE :

JPETAB Journal of Pharmacology and Experimental Therapeutics. (Williams & Wilkins Co., 428 E. Preston St., Baltimore, MD 21202) V.1- 1909/10- Volume(issue)/page/year: 94,65,1948

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rabbit

DOSE/DURATION :

7 gm/kg

TOXIC EFFECTS :

Behavioral - tremor Behavioral - convulsions or effect on seizure threshold Behavioral - muscle contraction or spasticity

REFERENCE :

IECHAD Industrial and Engineering Chemistry. (Washington, DC) V.15-62, 1923-70. For publisher information, see CHMTBL. Volume(issue)/page/year: 15,628,1923

TYPE OF TEST :

LD50 - Lethal dose, 50 percent kill

ROUTE OF EXPOSURE :

Intravenous

SPECIES OBSERVED :

Rodent - rabbit

DOSE/DURATION :

330 mg/kg

TOXIC EFFECTS :

Behavioral - convulsions or effect on seizure threshold Lungs, Thorax, or Respiration - cyanosis Gastrointestinal - changes in structure or function of salivary glands

REFERENCE :

JPETAB Journal of Pharmacology and Experimental Therapeutics. (Williams & Wilkins Co., 428 E. Preston St., Baltimore, MD 21202) V.1- 1909/10- Volume(issue)/page/year: 94,65,1948 *** U.S. STANDARDS AND REGULATIONS *** EPA FIFRA 1988 PESTICIDE SUBJECT TO REGISTRATION OR RE-REGISTRATION FEREAC Federal Register. (U.S. Government Printing Office, Supt. of Documents, Washington, DC 20402) V.1- 1936- Volume(issue)/page/year: 54,7740,1989 *** NIOSH STANDARDS DEVELOPMENT AND SURVEILLANCE DATA *** NIOSH OCCUPATIONAL EXPOSURE SURVEY DATA : NOHS - National Occupational Hazard Survey (1974) NOHS Hazard Code - 19680 No. of Facilities: 28313 (estimated) No. of Industries: 157 No. of Occupations: 112 No. of Employees: 307205 (estimated) NOES - National Occupational Exposure Survey (1983) NOES Hazard Code - X1191 No. of Facilities: 22 (estimated) No. of Industries: 1 No. of Occupations: 2 No. of Employees: 130 (estimated) No. of Female Employees: 108 (estimated) NOES - National Occupational Exposure Survey (1983) NOES Hazard Code - 19680 No. of Facilities: 49113 (estimated) No. of Industries: 244 No. of Occupations: 182 No. of Employees: 1691218 (estimated) No. of Female Employees: 1083005 (estimated)