Not to be semantically confused with : Wall-rue (Asplenium ruta-muraria), Goat's-Rue (Galega officinalis), Rue-Leaved Saxifrage (Saxifraga tridactylites), Common Meadow-Rue (Thalictrum flavum),
Dusty Meadow-rue (Thelypteris palustris), Lesser Meadow-Rue (Thalictrum minus),
Chinese Meadow-rue (Thalictrum delavayi), French Meadow-Rue (Thalictrum aquilegiifolium) nor with
Alpine Meadow-rue (Thalictrum alpinum) [plants with similar names belonging to differing families].
Uniquely identifiable characteristics
Distinguishing Feature : There is no other plant quite like this!
It is a neophyte which can become naturalised on rough ground, producing seedlings in waste places, shrubberies or cracks in walls.
Rue has quite a plethora of differing secondary metabolites, many being toxic to various degrees. It contains the
Coumarins Scopoletin and Umbelliferone plus two first discovered in Rue:
The essential oil from Rue can cause contact dermatitis and it also contains photosensitive substances (Furocoumarins) which can not only cause skin blisters which lasts up to 2 years but also severe damage to the kidneys. Therapeutic doses can cause depression, fatigue, cramp, sleep disorders and dizziness. Fresh sap from the leaves may cause a week heart pulse, fainting, sleepiness, painful stomach cramps, abortion, a swollen tongue and make your skin feel cool. But despite these symptoms, Rue has traditionally been used in Indian and many other countries as a medicine. The herb has been used as an antispasmodic, irritant, abortifacient, and for the treatment if cough, colic and wind. The leaves have been used for amenorrhea, menorrhea, colic and externally for sciatica, headache, muscular chest pain, bronchitis and arthritis. The oil is an anti-spasmodic, anti-epileptic, a rubifacient and an emmenogogue. But your Author would not use Rue for any of these things! If he needed then he would go to the doctors for a prescription from a proper chemist where there is usually only one active compound in a highly-controlled dosage (rather than a whole plethora of differing potentially harmful compounds in unknown highly-variable quantities)...
Rue extracts are mutagenic and hepatotoxic. Large doses can cause violent gastric pain, vomiting, systemic complications, and death. Exposure to common rue, or herbal preparations derived from it, can cause severe phytophotodermatitis which results in burn-like blisters on the skin.
According to WebMed: " Rue is UNSAFE when used as a medicine. When taken by mouth, it can cause side effects such as stomach irritation, changes in mood, sleep problems, dizziness, spasms, serious kidney and liver damage, and death. When applied to the skin, it can cause rash and increased sensitivity to the sun "
Limonoids found in Rue, one called
Limonin, the other
Nomilin. They are phytochemical TetraNorTriTerpenoid compounds found in Citrus fruits and in 3 other plant families,
Rutacea and Meliaceae, the latter having no presence in the UK it being the Mahogany family. Limonoids contribute to the sweet (or sour) tastes of citrus fruits.
Nomilin is a new bitter compound found in Grapefruit juice, oranges, lemons and Rue. Nomilin is twice as bitter as Limonin.
At their core Limonoids contain a
FuroLactone (the two rings on the right-most, one above the other). Nomilin has a 7-membered ring (bottom left). They both have an epoxy bridge (depicted here with two pointed arrows holding an oxygen atom almost in the centre of the diagram). Typically Limonoids have four 6-membered rings plus a furan ring but in Nomilin one of those four rings is 7-membered.
COUMARINS and FUROCOUMARINS
Rutacultin is a Coumarin with extra moieties attached. It is found in herbs and spices, and in Rue. Rue also contains the
The other two compounds,
FuroCoumarins both found in Rue.
Other FuroCoumarins found in Rue are
Dictamnine, Xanthotoxin, Psoralen, Bergapten and isoPimpinellin. FuroCoumarins are far more toxic than
Coumarins because of the Furano moiety (the 5-membered ring with an oxygen atom in the ring).
Both Eduline and the more complex
Graveolinine - not shown here) are all
Quinoline alkaloid secondary metabolites to be found in Rue.
There are also a set of three variations on
Graveolin where the moiety bottom right of two fused rings are replaced by a zig-zag linear hydrocarbon chain of 10, 11 or 12 of CH2 units like the linear strings on the two ketone hydrocarbons shown below this pane.
FuroQuinoline alkaloids found in Rue (as is
Dictamnine itself - not shown here).
Kokusaginine, just like the other compounds with a heterocyclic nitrogen atom in a ring, is an oxacycle compound. It occurs in significant amounts in species of Rutaceae, including Rue. Both
Skimmianine inhibit the proliferation of cancer cells and it is suggested by a researcher that both of these compounds are to be recommended as starting materials to design other chemical structures that are even more effective at killing cancer cells than either of these two chemicals.
Skimmianine is also found in
Japanese Skimmia (Skimmia Japonica) (which is also in the same Rutaceae family as Rue). Skimmianine is ultimately derived from
Anthranilic Acid (which is found in abundance in Rue) via an 11-step biosynthetic process.
2-Nonanone (how many N's in that) is present not only in Rue but also in a great many other plants such as Banana, Ginger, Cloves, Coconut,
Melon but also in
Strawberry Jam, Wine, Beer and Cheese (probably amongst many others). It is a clear but slightly yellow liquid used a a flavouring and as a fragrance.
2-Undecanone, aka MethylNonylKetone is a colourless oil is also found in various plants such as Banana, cloves, ginger, guava, tomato and strawberry as well as in the plant Chameleon (Houttuynia cordata) and in Rue. It has a strong odour and is used primarily as an insect repellent but is also used for flavouring and in perfume. It tastes waxy or of fat, creamy or a bit cheesy but comes up smelling of Roses (or of Citrus fruit, such as Pineapple).
Acridones always have two benzene rings straddling a moiety with an exocyclic =O moiety directly opposite a nitrogen atom in the ring. They also have a ketone moiety (the exocyclic =O just above the nitrogen atom, hence the 'one' [pronounced 'own'] ending in 'Acridone').
Arborinine (aka Arborin) is found in Rue and in the leaves of the plant Glycosmis parva and exhibits strong anti-cancer activity and inhibits tumour spheroid growth more effectively than do the chemotherapy drugs Cisplatin, Gemcitabine or Bleomycin. Also, unlike cisplatin, it activates caspase-dependent cancer-cell apoptosis without inducing a DNA damage response. It also stops cancer cell migration.It also stops cancer cell migration. It thus shows potential for use in treating cervical cancer. It also exhibited moderate levels of anti-hepatitis C (HCV) activity.
The biosynthesis of
Melicopicine within Rue, with two extra epoxy groups on the lower side (left), makes it possible for the more complex Furo-Acridones and Acridone to also be constructed within Rue as shown below.
Evoxanthine is the odd one out in this section: it is the only compound shown here with a
Dioxolane moiety (the 5 membered ring on the left with two oxygen atoms in the ring).
It occurs widely in the Rutaceae family of plants and in several other un-related species. In crystaline form it occurs as yellow cubes with a strong blue-violet fluorescence.
The chemicals shown below that have a 5-membered 2,5-dihydrofuran ring (with only one oxygen atom in the ring).
Rutacridone is a Furo-acridine on account of its 5-membered ring with one oxygen atom within.
Rutacridone Epoxide is similar to Rutacridone, except that it has swapped one moiety for a much more potent epoxide moiety (the triangular moiety with an oxygen atom at one apex).
Like all the other chemicals shown on the Rue page it occurs in Rue. This one exhibits anti-microbial properties (as probably do the many other compounds shown on this page), slowing the growth of microorganisms including fungi, bacteria, viruses and protozoans, but your Author wonders if that includes covid-19, which is rampant around the world in the year 2020 (and probably many other years to come). But because the epoxy group usually makes compounds more toxic, this one in particular is probably more effective than most.
20-HydroxyRutacridone Epoxide has swapped a CH3 moiety for another -OH group (it already has one at the top).
Compared to Rutacridone - Acronycine has the furano ring replaced by a pyrano moiety. This compound is a potent anti-tumor agent with a broad spectrum of modest activity including numerous solid tumours.