Furoquinoline alkaloids are a group of

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s with simple structure. Distribution of this group of alkaloids is essentially limited to plant family

Rutaceae The Rutaceae () is a family (biology), family, commonly known as the rueRUTACEAE
in Bo ...

. The simplest member of this group is dictamnine and most widespread member is

skimmianine Skimmianine is a furoquinoline alkaloid found in '' Skimmia japonica'', a flowering plant in family Rutaceae that is native to Japan and China. It is a known acetylcholinesterase inhibitor. Biosynthesis The biosynthesis of skimmianine starts f ...

. A furoquinoline alkaloid, dictamnine, is very common within the family Rutaceae. It is the main alkaloid in the roots of ''

Dictamnus albus ''Dictamnus albus'' is a species of flowering plant in the family Rutaceae. It is also known as burning bush, dittany, gas plant or fraxinella. This herbaceous perennial has several geographical variants. It is native to warm, open woodland habit ...

'' and responsible for the

mutagenicity In genetics, a mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer in ...

of the drug derived from crude extracts. Dictamnine was also reported to be a

phototoxic Phototoxicity, also called photoirritation, is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity. The skin response resembles an exaggerated sunburn. The involved chem ...

and photomutagenic compound. It participates in the severe skin phototoxicity of the plant. Another furoquinoline alkaloid, skimmianine, has strong antiacetylcholinesterase activity.

Chemistry

Thomas first isolated dictamnine from Rutaceae in 1923. It is very weak base, shows similar reaction with

methyl iodide Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one h ...

and

dimethyl sulfate Dimethyl sulfate (DMS) is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as ( CH3)2 SO4 or Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agen ...

diazomethane Diazomethane is an organic chemical compound with the formula CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow ga ...

, does not form a derivative but go through

isomerization In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. Enolization is an example of isomerization, as is tautomer ...

to isodictamnine. Dictamine have linear structure which is confirmed as it forms dictamnic acid by

oxidative degradation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

with

potassium permanganate Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, which dissolves in water as K+ and ions to give an intensely pink to purple solution. Potassium permanganate is widely us ...

Dieckmann cyclization The Dieckmann condensation is the intramolecular chemical reaction of diesters with base to give β-keto esters. It is named after the German chemist Walter Dieckmann (1869–1925). The equivalent intermolecular reaction is the Claisen condensati ...

followed by

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

and

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

confirmed the structure of the acid. Skimmianine, another common furoquinoline alkaloid also shows a very similar type of chemistry to dictamine. Skimmianine also has a linear structure as it gave 3-ethyl-4,7,8-trimethoxy-2-quinolone from hydrolysis.

Pharmacological properties

Some furoquinoline alkaloids have been found to have ''

in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...

'' pharmacological properties such as antimicrobial, antiviral, mutagenic and cytotoxic activities. They also show antiplatelet aggregation, inhibition of various enzymes, antibacterial, and antifungal activity. Dictamnine has the property of causing smooth muscle contraction. Skimmianine, extracted from '' Esenbeckia leiocarpa'' Engl. (Rutaceae), a native tree from Brazil popularly known as guarantã, show acetylcholinesterase inhibition. Furoquinoline alkaloids extracted from ''

Teclea afzelii ''Vepris'' is a genus of plant in family Rutaceae. It comprises around 90 species, mainly from tropical Africa, Madagascar and the Mascarene Islands and at a lesser extent Arabia and India. Species , Plants of the World Online (PoWO) accepted t ...

'' (Rutaceae) plants, collected at Elounden, centre province of Cameroon, have

antiplasmodial ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a verteb ...

activities. Another study shows that some furoquinoline alkaloids have ''in vitro'' activity against ''

Plasmodium falciparum ''Plasmodium falciparum'' is a Unicellular organism, unicellular protozoan parasite of humans and is the deadliest species of ''Plasmodium'' that causes malaria in humans. The parasite is transmitted through the bite of a female ''Anopheles'' mos ...

'', one of the species of ''

Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a Hematophagy, blood-feeding insect host (biology), host which then inj ...

'' that causes malaria in humans. One furoquinoline alkaloid, 5-(1,1-dimethylallyl)-8-hydroxy-furo -3-buinolone, shows antifungal properties against ''

Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name ' ...

'', ''

Sclerotium rolfsi A sclerotium (; : sclerotia () is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant u ...

'', and ''

Fusarium solani ''Fusarium solani'' is a species complex of at least 26 closely related filamentous fungi in the division Ascomycota, family Nectriaceae. It is the anamorph of ''Nectria haematococca''. It is a common soil inhabiting mold. ''Fusarium solani'' ...

''. These fungi cause root-rot and wilt diseases in potato, sugar beet and tomato.

Spectral properties

For

UV spectra Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ...

an intense band is observed at 235 nm and very broad band in region 290-335 nm. Compared to UV,

IR spectra Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functiona ...

shows less characteristics: 1090–1110 cm⁻¹ region shows a band but don't indicate a particular vibration.

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic f ...

is the best way to observe the structure of furoquinoline alkaloids. C-2 proton gives response in 7.50-7.60 ppm region and C-3 proton gives response in 6.90-7.10 ppm region. Aromatic methoxy group give responses in 4.0-4.2 ppm region but 4-methoxy group give responses in ~4.40 ppm region.

References

External links

* {{commons category-inline , Furoquinolines Furans Quinoline alkaloids Furoquinolines