D LIMONENE

D LIMONENE

CAS NO: 5989-27-5 / 95327-98-3
EC NO: 227-813-5

SYNONYMS:

D LIMONENE; (R)-(+)-Limonene; (+)-Carvene; (+)-p-Mentha-1,8-diene; (R)-(+)-Dipentene; D-Limonene; (4R)-1-Methyl-4-(1-methylethenyl)-cyclohexene; 4(R)-Isopropenyl-1-methylcyclohexene; p(R)-Mentha-1,8-diene; LIMONENE; Dipentene; Cinene; 138-86-3; Cajeputene; DL-Limonene; D-Limonene; (+)-Limonene; 5989-27-5; (R)-(+)-Limonene; (+)-(4R)-Limonene; (+)-carvene; (4R)-Limonene; D-(+)-Limonene; (R)-Limonene; (R)-p-Mentha-1,8-diene; Citrene; (+)-p-Mentha-1,8-diene; (R)-4-Isopropenyl-1-methyl-1-cyclohexene; D-Limonen; (D)-Limonene; Carvene; Glidesafe; Glidsafe; Refchole; (+)-R-Limonene; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (4R)-; d-p-Mentha-1,8-diene; Limonene, D-; (+)-4-Isopropenyl-1-methylcyclohexene; (+)-Dipentene; (4R)-4-isopropenyl-1-methylcyclohexene; (R)-(+)-p-Mentha-1,8-diene; Biogenic SE 374; (+)-alpha-Limonene; d-Limonene (natural); Limonene, (+)-; (R)-1-Methyl-4-(1-methylethenyl)cyclohexene; (+)-(R)-Limonene; Hemo-sol; (4R)-(+)-Limonene; UNII-GFD7C86Q1W; MFCD00062991; CCRIS 671; r-(+)-limonene; FEMA No. 2633; EC 7; HSDB 4186; D-1,8-p-Menthadiene; NCI-C55572; EINECS 227-813-5; p-Mentha-1,8-diene, (R)-(+)-; (R)-1-Methyl-4-(prop-1-en-2-yl)cyclohex-1-ene; GFD7C86Q1W; 4betaH-p-mentha-1,8-diene; (+)-1,8-para-Menthadiene; AI3-15191; CHEBI:15382; 1-Methyl-4-(1-methylethenyl)cyclohexene, (R)-; (+) Limonene; (4R)-1-methyl-4-(prop-1-en-2-yl)cyclohex-1-ene; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (R)-; (4R)-1-methyl-4-isopropenylcyclohex-1-ene; (R)-(+)-4-Isopropenyl-1-methylcyclohexene; (4R)-1-methyl-4-(1-methylethenyl)cyclohexene; (+)-Limonene, stabilized with 0.03% tocopherol; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (theta)-; (+)-Limonene, 96%, unstabilized; D-limonene [JAN]; (4R)-4-isopropenyl-1-methyl-cyclohexene; Citrus stripper oil; Terpenes and Terpenoids, limonene fraction; Sulfate turpentine, distilled; Dextro-limonene; d limonene; citre ne; 65996-98-7; EINECS 266-034-5; D-(+)-Limonen; limonene, (R)-isomer; D-Limonene Reagent Grade; DSSTox_CID_778; (4R)-1-methyl-4-prop-1-en-2-ylcyclohexene; (4R)-limonene derivatives; EC 227-813-5; DSSTox_RID_75785; DSSTox_GSID_20778; CHEMBL449062; PARA-MENTHA-1,8-DIENE; DTXSID1020778; (R)-(+)-Limonene, 95%; (R)-(+)-Limonene, 97%; ZINC96751; CS-M3273; KS-000001WP; (R)-(+)-Limonene, >=93%; Tox21_200400; 6458A; SBB055254; AKOS015899935; CCG-266134; DB08921; LMPR0102090013; LS-1427; NE11118; (R)-(+)-Limonene, analytical standard; NCGC00248591-01; NCGC00257954-01; SC-65387; CAS-5989-27-5; L0047; 0105; C06099; (4R)-1-Methyl-4-(prop-1-en-2-yl)cyclohexene; (4R)-1-methyl-4-(1-methylvinyl)cyclohex-1-ene; J-502148; W-105295; Q27888324; (R)-(+)-Limonene, primary pharmaceutical reference standard; UNII-9MC3I34447 component; XMGQYMWWDOXHJM-JTQLQIEISA-N; (R)-(+)-Limonene, purum, >=96.0% (sum of enantiomers, GC); (R)-(+)-Limonene, technical, ~90% (sum of enantiomers, GC); kautschin; p-Mentha-1,8-diene; Dipenten; Eulimen; Nesol; 1,8-p-Menthadiene; polylimonene; Cajeputen; Limonen; Cinen; Cyclohexene, 1-methyl-4-(1-methylethenyl)-; Inactive limonene; Acintene DP dipentene; 1-Methyl-4-(1-methylethenyl)cyclohexene; Polydipentene; Dipanol; Unitene; alpha-Limonene; Flavor orange; Orange flavor; Limonene polymer; Goldflush II; Acintene DP; Dipentene polymer; Di-p-mentha-1,8-diene; 1,8(9)-p-Menthadiene; 4-Isopropenyl-1-methyl-1-cyclohexene; 4-Isopropenyl-1-methylcyclohexene; (+/-)-Limonene; d,l-Limonene; Dipentene 200; Polymerized dipentene; (+-)-Dipentene; (+-)-Linonene; p-Mentha-1,8-diene, dl-; Caswell No. 526; Zonarez 7085; Zonarez 7115; DL-4-Isopropenyl-1-methylcyclohexene; 1-Methyl-4-isopropenyl-1-cyclohexene; delta-1,8-Terpodiene; (+-)-alpha-Limonene; MENTHA-1,8-DIENE (DL); Dipentene, crude; .alpha.-Limonene; Limonene, dl-; NSC 21446; PC 560; 1-methyl-4-prop-1-en-2-ylcyclohexene; p-Mentha-1,8-diene, polymers; HSDB 1809; HSDB 1931; NSC 844; 1-Methyl-4-isopropenylcyclohexene; p-Mentha-1,8-diene, (+-)-; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, homopolymer; 1-methyl-4-(prop-1-en-2-yl)cyclohex-1-ene; EINECS 205-341-0; EINECS 231-732-0; UN2052; (+-)-(RS)-limonene; .delta.-1,8-Terpodiene; 1-Methyl-p-isopropenyl-1-cyclohexene; EPA Pesticide Chemical Code 079701; AI3-00739; 7705-14-8; CHEBI:15384; d(R)-4-Isopropenyl-1-methylcyclohexene; NCGC00163742-03; (1)-1-Methyl-4-(1-methylvinyl)cyclohexene; DSSTox_CID_9612; DSSTox_RID_78787; DSSTox_GSID_29612; Terpenes and Terpenoids, limonene fraction; beta-Limonene; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (.+/-.)-; LEMON OIL; Limonene, L-; Lemon extract; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (S)-; d-Limonene (JAN); Sweet orange oil; Oils, lemon; P-Mentha-1,8-diene, (S)-(-)-; CAS-138-86-3; Oils, orange, sweet; 65996-98-7; DIPENTENE (+-); Terpodiene; Ciene; Cyclil decene; Lemon tincture; EINECS 227-815-6; Neroli oil; Orange oil; Cedro oil; Orange leaf oil; Citrus limon oil; Extract of lemon; Oil of lemon; Oil sweet orange; Oils, orange; Achilles dipentene; Orange flower oil; Absolute petitgrain; Orange oil, sweet; 4-isopropenyl-1-methyl-cyclohexene; Lemon oil, Guinea; Citrus sinensis oil; Dipentene, technical, for use as solvent (for the paint industry), mixture of various terpenes; Lemon petigrain oil; Lemon oil, Italian; limonene derivatives; Citrus limon extract; Lemon petitgrain oil; Neroli oil, pommade; Oil of sweet orange; AI3-25390; c0626; Mentha-1,8-diene; Absolue orange flower; Lemon oil concentrate; Lemon oil, distilled; Oils, citrus limonia; Orange oil, distilled; p-Mentha-1, dl-; Dipentene, homopolymer; Orange flower absolute; Orange oil concentrate; Absolute orange flowers; (.+-.)-Limonene; Caswell No. 425A; d-Limonene (Limonene); limonene, (S)-isomer; OIL OF ORANGE; (.+-.)-Dipentene; 1-Methyl-4-(1-methylethenyl)cyclohexene, (S)-; 4-mentha-1,8-diene; Orange peel oil, sweet; Citrus sinensis peel oil; Petitgrain citronnier oil; (.+/-.)-Dipentene; (.+/-.)-Limonene; DIPENTENE 38 PF; limonene, (+-)-isomer; Limonene, (+/-)-; Neat oil of sweet orange; ESSENCE DE PIN PF; DL-p-mentha-1,8-diene; Mentha-1,8-diene, DL; Dipentene, technical grade; Cyclohexene, (.+-.)-; Dipentene, p.a., 95%; Orange sweet oil, expressed; Orange flower water absolute; p-Mentha-1,8(9)-diene; Orange oil, distilled, sweet; Orange oil, sweet, expressed; CCRIS 683; Dipentene, mixture of isomers; Sweet orange oil, terpeneless; CHEMBL15799; (R)-p-Mentha-1,8-diene.; Monocyclic terpene hydrocarbons; Absolue orange flower decolor; Citrus medica var. limonum oil; FEMA No. 2822; FEMA No. 2853; Methyl-4-isopropenylcyclohexene; NSC844; (.+/-.)-.alpha.-Limonene; Absolute orange flower from water; DTXSID2029612; (+/-)-p-Mentha-1,8-diene; CTK5C8417; HSDB 1934; HSDB 1944; KS-00000WVS; p-Mentha-1, (.+-.)-; NSC-844; HMS3264E05; Methyl-4-isopropenyl-1-cyclohexene; HY-N0544; NSC21446; Tox21_112068; Tox21_201818; Tox21_303409; NSC-21446; NSC757069; STK801934; 1-methyl-4-isopropenylcyclohex-1-ene; AKOS009031280; Cyclohexene, ;4-Isopropenyl-1-methyl-; Methyl-4-(1-methylethenyl)cyclohexene; WLN: L6UTJ A1 DY1 & U1; CCG-214016; EPA Pesticide Chemical Code 040501; EPA Pesticide Chemical Code 040517; LS-2278; LS-2880; MCULE-2462317444; NSC-757069; p-Mentha-1,8-diene, (.+/-.)-; p-Mentha-1,8-diene, polymers ; (8CI); UN 2052; (+/-)-p-Mentha-1,8-diene homopolymer; Limonene 1000 microg/mL in Isopropanol; NCGC00163742-01; NCGC00163742-02; NCGC00163742-04; NCGC00163742-05; NCGC00257291-01; NCGC00259367-01; 8050-32-6; Dipentene [UN2052] [Flammable liquid]; LS-89490; LS-89491; LS-98217; NCI60_041856; p-Mentha-1,8-diene, homopolymer (7CI); SC-80005; 1-methyl-4-(1-methylethenyl); cylcohexene; 1-methyl-4-(prop-1-en-2-yl)cyclohexene; 4-(1-methylethenyl)-1-methyl-cyclohexene; Dipentene [UN2052] [Flammable liquid]; 1-methyl-4-(1-methylvinyl)cyclohex-1-ene; Cyclohexene, 1-methyl-4-(1-methylethynyl); DB-053490; DB-072716; LS-180589; LS-181342; CS-0009072; FT-0600409; FT-0603053; FT-0605227; L0046; ST51046654; EN300-21627; AB01563249_01; Q278809; J-007186; (+/-)-1-Methyl-4-(1-methylvinyl)cyclohexene; C06078; D00194; SR-01000872759; SR-01000872759-1; 1-METHYL-4-PROP-1-EN-2-YL-CYCLOHEXENE; J-520048; Orange oil, terpeneless; Cyclohexene,3-methyl-6-(1-methylethenyl)-, (3R,6R)-rel-; ORANGE PEEL, SWEET, OIL; ORANGE, OIL, DISTILLED; Dipentene, mixt. of limonene, 56-64%, and terpinolene, 20-25&; 555-08-8; 8022-90-0; (S)-(−)-Limonene; (-)-(4S)-Limonene; (-)-(S)-limonene; (-)-Carvene; (-)-Limonene; (-)-p-Mentha-1,8-diene (4S)-1-Methyl-4-(prop-1-en-2-yl)cyclohexene; (4S)-4-Isopropenyl-1-methylcyclohexen; (4S)-4-Isopropenyl-1-methylcyclohexene; (4S)-4-Isopropényl-1-méthylcyclohexène; (S)-(-)-Limonene (S)-4-Isopropenyl-1-methyl cyclohexene; (S)-Limonene; 227-815-6 [EINECS]; 2323991 [Beilstein]; 4-Isopropenyl-1-methyl-1-cyclohexene; 5989-54-8 [RN]; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (4S)- [ACD/Index Name]; Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (S)-; Limonene; L-Limonen; L-limonene; MFCD00001558 [MDL number]; p-Mentha-1,8-diene, (S)-(-)-; S-(-)-LIMONENE; (-)-(S)-limonene; (-)-(4S)-limonene; (−)-Carvene; (−)-p-Mentha-1,8-diene; (4S)-limonene; (4S)-1-methyl-4-(prop-1-en-2-yl)cyclohex-1-ene; (4S)-1-methyl-4-isopropenylcyclohex-1-ene; (4S)-1-methyl-4-prop-1-en-2-ylcyclohexene; (4S)-1-methyl-4-prop-1-en-2-yl-cyclohexene; (4S)-4-isopropenyl-1-methyl-cyclohexene; (4S)-limonene; (−)-Carvene; (−)-p-Mentha-1,8-diene; (S)-(-)-4-Isopropenyl-1-methylcyclohexene; (S)-(-)-p-mentha-1,8-diene; (S)-(−)-Limonene; (S)-1-Methyl-4-(1-methylethenyl)cyclohexene; (S)-1-Methyl-4-(prop-1-en-2-yl)cyclohex-1-ene; (S)-p-mentha-1,8-diene

D LIMONENE

Limonene is the oil extracted from the peels of oranges and other citrus fruits.

People have been extracting essential oils like limonene from citrus fruits for centuries. Today, limonene is often used as a natural treatment for a variety of health issues and is a popular ingredient in household items.

However, not all of limonene’s benefits and uses are supported by science.

Limonene is a chemical found in the rind of citrus fruits, such as lemons, limes, and oranges. It is especially concentrated in orange peels, comprising around 97% of this rind’s essential oils.

It’s often referred to as d-limonene, which is its main chemical form.

Limonene belongs to a group of compounds known as terpenes, whose strong aromas protect plants by deterring predators.

Limonene is one of the most common terpenes found in nature and may offer several health benefits. It has been shown to possess anti-inflammatory, antioxidant, anti-stress, and possibly disease-preventing properties.

Limonene is a popular additive in foods, cosmetics, cleaning products, and natural insect repellants. For example, it’s used in foods like sodas, desserts, and candies to provide a lemony flavor.

Limonene is extracted through hydrodistillation, a process in which fruit peels are soaked in water and heated until the volatile molecules are released via steam, condensed, and separated.

Due to its strong aroma, limonene is utilized as a botanical insecticide. It’s an active ingredient in multiple pesticide products, such as eco-friendly insect repellents.

Other household products containing this compound include soaps, shampoos, lotions, perfumes, laundry detergents, and air fresheners.

Additionally, limonene is available in concentrated supplements in capsule and liquid form. These are often marketed for their supposed health benefits.

This citrus compound is also used as an aromatic oil for its calming and therapeutic properties.

Limonene has been studied for its potential anti-inflammatory, antioxidant, anticancer, and heart-disease-fighting properties.

However, most research has been conducted in test tubes or on animals, making it difficult to fully understand the role of limonene in human health and disease prevention.

Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The d-isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring agent in food manufacturing. It is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products. The less common l-isomer is found in mint oils and has a piny, turpentine-like odor. The compound is one of the main volatile monoterpenes found in the resin of conifers, particularly in the Pinaceae, and of orange oil.

Limonene takes its name from French lemon. Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains d-limonene ((+)-limonene), which is the (R)-enantiomer. Racemic limonene is known as dipentene. d-Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation.

D-limonene is a compound sourced from the peel of citrus fruits, including include oranges, mandarins, limes, and grapefruit. Sold as a dietary supplement, D-limonene is said to offer a variety of health benefits, in part because of its ability to dissolve fats—including cholesterol. Proponents believe that D-limonene can aid in weight loss as well as treat or prevent certain diseases, including cancer.

D-limonene takes its name from the lemon and is often used as a flavoring agent in foods. It differs from a less common type of limonene known as L-limonene, which is found in mint oil.

Alternative practitioners have long touted the benefits of D-limonene, claiming that it not only burns fat but reduces inflammation and kills disease-causing germs. Many of these beliefs stem from its use in industry, where D-limonene is commonly used to make hand sanitizers, perfumes, botanical pesticides, and chemical solvents.

Among some of the conditions that D-limonene is believed to prevent or treat are:

Bronchitis
Cancer
Diabetes
Gallstones
Gastroesophageal reflux disease (GERD)
Heartburn
High cholesterol
Inflammatory bowel disease (IBD)
Metabolic syndrome
Obesity
Peptic ulcers

Citrus essential oils rich in D-limonene are also used in aromatherapy to relieve stress.

To date, there is little solid evidence that D-limonene can treat any medical condition. With that said, a number of preliminary studies have hinted at benefits that may warrant further investigation.

Weight Loss:

There is some evidence that D-limonene can promote weight loss by lowering blood sugar and lipids associated with metabolic syndrome. A study reported that obese mice fed a high-diet diet supplemented with D-limonene experienced decreases in blood glucose, total cholesterol, and "bad" LDL cholesterol as well as increases in "good" HDL cholesterol.

These findings suggest that D-limonene may be useful in preventing or treating metabolic syndrome, although further research is needed to confirm such a benefit and determine the dose needed to be effective in humans.

Peptic Ulcers:

D-limonene may help reduce the risk of peptic ulcers and other inflammatory gastrointestinal diseases. According to the researchers, high concentrations of D-limonene in the essential oil of bitter orange served to protect the lining of the stomach of lab rats fed high-doses of alcohol and nonsteroidal anti-inflammatory drugs.

Contrary to popular belief, it did so not by suppressing stomach acid but by increasing the production of gastric mucus.

Despite the positive findings, it is unclear if D-limonene did so on its own or if some other component in the essential oil contributed. Further research is needed.

Cancer:

Alternative practitioners have long touted the anticancer properties of D-limonene. The effect is attributed to perillic acid, a substance released into the bloodstream when D-limonene is broken down by the body.

A number of test-tube studies have reported that D-limonene applied to cancer cells can trigger apoptosis (programmed cell death). This is considered significant given that this naturally occurring event, which allows old cells to be replaced by new cells, does not occur with cancer cells. This effect was seen in studies involving colon cancer, skin cancer and other common malignancies.

It remains unclear whether taking D-limonene by mouth might render the same benefit, however. A study aimed to evaluate this effect by providing 43 women with breast cancer with 2 grams of D-limonene daily for two to six weeks.

At the end of the study period, a biopsy of breast tissue showed high concentrations of D-limonene but little of the perillic acid needed to arrest cancer growth. Further investigation is needed to determine whether higher doses or longer treatment may help improve these results.

Possible Side Effects:

Widely used as a food flavoring, D-limonene is generally considered safe and has been used for up to a year in clinical research without incident. Common side effects include stomach upset and reflux.

At excessively high doses, D-limonene has been known to hematuria.

The safety of D-limonene has not been established in children, pregnant women, or nursing mothers. As a precaution, always speak with your doctor before using D-limonene or any other supplement if you are pregnant or breastfeeding. As the benefits of D-limonene in children are unknown, it is best to play it safe and avoid the supplement altogether.

D-limonene may cause irritation if applied to the skin. The same applies to citrus essential oils that are characteristically high in D-limonene. To reduce irritation, always mix essential oils with a carrier oil (such as avocado oil or sweet almond oil) if you intend to use them for massage purposes.

Limonene has been shown to reduce inflammation in some studies.

While short-term inflammation is your body’s natural response to stress and is beneficial, chronic inflammation can harm your body and is a major cause of illness. It’s important to prevent or reduce this type of inflammation as much as possible.

Limonene has been shown to reduce inflammatory markers that relate to osteoarthritis, a condition characterized by chronic inflammation.

A test-tube study in human cartilage cells noted that limonene reduced nitric oxide production. Nitric oxide is a signaling molecule that plays a key role in inflammatory pathways.

In a study in rats with ulcerative colitis — another disease characterized by inflammation — treatment with limonene significantly decreased inflammation and colon damage, as well as common inflammatory markers.

Limonene has demonstrated antioxidant effects as well. Antioxidants help reduce cell damage caused by unstable molecules called free radicals.

Free radical accumulation can lead to oxidative stress, which may trigger inflammation and disease.

One test-tube study revealed that limonene may inhibit free radicals in leukemia cells, suggesting a decrease in inflammation and cellular damage that would normally contribute to disease.

Although promising, these effects need to be confirmed by human studies.

Aside from the benefits listed above, limonene may:

Reduce appetite: The scent of limonene has been shown to significantly reduce appetite in blowflies. However, this effect has not been studied in humans.
Decrease stress and anxiety: Rodent studies suggest that limonene could be used in aromatherapy as an anti-stress and anti-anxiety agent.
Support healthy digestion: Limonene may protect against stomach ulcers. In a study in rats, citrus aurantium oil, which is 97% limonene, protected nearly all of the rodents against ulcers caused by medication use.

Limonene is considered safe for humans with little risk of side effects. The Food and Drug Administration (FDA) recognizes limonene as a safe food additive and flavoring.

However, when applied directly to the skin, limonene may cause irritation in some people, so caution should be used when handling its essential oil.

Limonene is sometimes taken as a concentrated supplement. Because of the way your body breaks it down, it’s likely safe consumed in this form. That said, human research on these supplements is lacking.

Notably, high-dose supplements may cause side effects in some people. What’s more, insufficient evidence exists to determine whether limonene supplements are acceptable for pregnant or breastfeeding women.

d-Limonene has been produced since 1995 and has been used as a flavor and fragrance additive in cleaning and cosmetic products, food, beverages, and pharmaceuticals. It is also increasingly used as a solvent. It is used in the manufacturing of resins, as a wetting and dispersing agent, and in insect control. It is present in most of the essential oils commonly used in Australia, particularly citrus oils. In the workplace, products such as hand cleaners, industrial cleaners, degreasers, and strippers may also contain limonene as a solvent. Industrial limonene is produced by alkaline extraction of citrus residues and steam distillation. This distillate contains more than 90% d-limonene.

Limonene is used as a substitute for chlorinated hydrocarbons, chlorofluorocarbons, and other solvents. It is used in degreasing metals (30% limonene) prior to industrial painting, for cleaning in the electronics industry (50–100% limonene), for cleaning in the printing industry (30–100% limonene), and in paint as a solvent. Limonene is also used as a solvent in histology laboratories and as a flavor and fragrance additive in food, household cleaning products, and perfumes. d-Limonene has been used as a gallstone solubilizer in humans.

d-Limonene has also been used as a sorption promoter or accelerant for improving transdermal drug delivery and works by penetrating the skin to reversibly decrease barrier resistance. Commercial mixtures of d-limonene molecules may contain other forms of limonene (l-limonene and d,l-limonene), which are called terpenes, and related compounds such as p-cumene.

Some studies have indicated that limonene has anticancer effects. Limonene increase the levels of liver enzymes involved in detoxifying carcinogens. The glutathione-S-transferase (GST) system eliminates carcinogens. The GST system can be promoted by limonene in the liver and small bowel leading to a decrease in the damaging effects of carcinogens. Animal studies demonstrated that dietary limonene reduced mammary tumor growth.

Limonene is a mild skin and eye irritant. Ingestion of 20 g of d-limonene caused diarrhea and a temporary increase in protein in the urine (proteinurea) in five male volunteers. These data, in addition to the low acute toxicity in animal tests, suggest that d-limonene is not very toxic by ingestion.

Air levels of d-limonene may irritate the eyes and airways of some people, especially when the levels build up indoors (see above for discussion about gas phase reactions between ozone and terpenes which can be a significant source of secondary organic aerosols).

d-Limonene has been used successfully for the postoperative dissolution of retained cholesterol gallstones.

Limonene, which is found in oils obtained from many Citrus plants, is used for aromatic purposes in the cosmetic industry as well as for drug production in order to facilitate the percutaneous transfer of drugs in vitro and in vivo. It is also used as sweetener in some foods and as a fragrance in soaps and perfumes. Based on in vitro studies, it is claimed that high concentrations of limonene are needed for its pharmacological effects. This chapter aims to provide knowledge and general information about limonene and its health effects.

Polarity of limonene is too low. Therefore it blocks the passage of limonene through cell membranes and leads to less activity.

Limonene can be completely absorbed in humans and other mammalian species. It can be rapidly distributed in most of the tissues and quickly metabolized into various active metabolites. Limonene and/or its active metabolites can be found in serum, liver, lung, kidney, and many tissues. This important monoterpene can accumulate in adipose tissue and mammary glands.

Limonene is a naturally occurring compound found mainly in the skin of certain plants and fruits, including lemons and oranges. It is used in cleaning products for two reasons: it has a pleasant, lemon-orange smell, and it acts as a solvent to help clean.

It is from a large family of natural substances called terpenes, and it has no colour and its toxicity is low. However, you might have heard about it recently because, when it reacts with ozone in the air, it undergoes change which releases tiny amounts of other compounds, including formaldehyde.

Peeling an orange releases orange oil into the air. As orange oil is 90% limonene you can get more exposure by peeling an orange than from using cleaning products.

Limonene is a naturally occurring compound found mainly in the skin of certain plants and fruits, including lemons and oranges. It is used in cleaning products for two reasons: it has a pleasant, lemon-orange smell, and it acts as a solvent to help clean.

It is from a large family of natural substances called terpenes, and it has no colour and its toxicity is low. However, you might have heard about it recently because, when it reacts with ozone in the air, it undergoes change which releases tiny amounts of other compounds, including formaldehyde.

Peeling an orange releases orange oil into the air. As orange oil is 90% limonene you can get more exposure by peeling an orange than from using cleaning products.

Limonene is a cyclic monoterpene compound. It shows stereoisomerism; there are two isomers of limonene as the D isomer and the L isomer. The key difference between limonene and D limonene is that limonene is a cyclic monoterpene whereas D limonene is the D isomer of limonene.

FIRST AID MEASURES
    
· General information:
If health disorder happens, call for medical help immediately. Immediately remove any clothing soiled by the product.

· After inhalation:
Supply fresh air and to be sure call for a doctor.
In case of unconsciousness place patient stably in side position for transportation.

· After skin contact: Immediately wash with water and soap and rinse thoroughly.

· After eye contact: Rinse opened eye for several minutes under running water.

· After swallowing: Do not induce vomiting; call for medical help immediately.

FIREFIGHTING MEASURES

· Suitable extinguishing agents: CO2, alcohol resistant foam, powder, water spray.

· For safety reasons unsuitable extinguishing agents: Water with full jet

· Special hazards arising from the substance or mixture In case of fire, the following can be released:
Carbon monoxide (CO)
Carbon dioxide (CO2)
Smoke and soot
Do not use water with full jet to prevend fire spreading.

Advice for firefighters

· Protective equipment: Wear self-contained respiratory protective device.

· Additional information
Cool endangered receptacles with water spray.
Collect contaminated fire fighting water separately. It must not enter the sewage system.
Dispose of fire debris and contaminated fire fighting water in accordance with official regulations.

· Environmental precautions:
Do not allow to penetrate the ground/soil.
Do not allow product to reach sewage system or any water course.
Inform respective authorities in case of seepage into water course or sewage system. Do not allow to enter sewers/ surface or ground water.

Methods and material for containment and cleaning up:
Wipe up little amounts with absorbent material like cloth or pulp.
Water and cleansing agent
Absorb with incombustible liquid-binding material (sand, diatomite, universal binders). Dispose of contaminated material as waste. Ensure adequate ventilation.

HANDLING AND STORAGE

·· Information about fire - and explosion protection:
Fumes can combine with air to form an explosive mixture.
Moistened solids (e.g. cloth, pulp, filter panel, binder) has to be stored hermetically sealed and/or watered and proper disposed (see chapter 9 and 13).
Keep ignition sources away - Do not smoke.
Protect against electrostatic charges.

·Storage:
· Requirements to be met by storerooms and receptacles:
Store only in unopened original receptacles. Provide solvent resistant, sealed floor.

· Information about storage in one common storage facility: Store away from oxidising agents. 

· Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed receptacles. 

General Information:

    Form:    Fluid
    Colour:    Clear
· Odour:    Characteristic
· Odour threshold:    Not determined.
· pH-value:    Not determined.
· Change in condition
    Melting point/Melting range:    -74,3 °C
    Boiling point/Boiling range:    > 34 °C
· Flash point:    51 °C (ASTM D7094)
· Flammability (solid, gaseous):    Not applicable.
· Ignition temperature:    255 °C
· Decomposition temperature:    Not determined.
· Self-igniting: Product is not selfigniting; but in case of unpropitious storing conditions (air admission, heat accumulation) selfignition is possible for moistened solids (e.g. cloth, pulp, filter panels, binder).
· Danger of explosion: Product is not explosive. However, formation of explosive air/vapour mixtures are possible.
· Explosion limits:
    Lower:    0,7 Vol %
    Upper:    6,1 Vol %
· Vapour pressure at 20 °C:    2,3 hPa
· Density at 20 °C:    0,842 g/cm³
· Relative density    Not determined. 
· Vapour density    Not determined. 
· Evaporation rate    Not determined.
· Solubility in / Miscibility with water: Not miscible or difficult to mix.
· Partition coefficient (n-octanol/water): Not determined.
· Viscosity:
    Dynamic:    Not determined.
    Kinematic at 20 °C:    18 mm²/s

· UN NO: UN2319
· Class    3 (F1) Flammable liquids.
· Label    3