Remedy/Plants/Rubiaceae

Luculia gratissima is from Austin's Ferry, Tasmania, Australia. Credit: JJ Harrison.{{free media}}

The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family, consisting of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules and sympetalous actinomorphic flowers, of about 13,500 species in about 620 genera, which makes it the fourth-largest angiosperm family and has a cosmopolitan distribution; however, the largest species diversity is concentrated in the tropics and subtropics.

Remedies

The bark of trees in the genus Cinchona is the source of a variety of alkaloids, the most familiar of which is quinine, one of the first agents effective in treating malaria. Woodruff (Galium odoratum) is a small herbaceous perennial that contains coumarin, a natural precursor of warfarin, and the South American plant Carapichea ipecacuanha is the source of the emetic ipecac. Psychotria viridis is frequently used as a source of dimethyltryptamine in the preparation of ayahuasca, a psychoactive decoction. The bark of the species Breonadia salicina have been used in traditional African medicine for many years. The leaves of the Kratom plant (Mitragyna speciosa) contain a variety of alkaloids, including several psychoactive alkaloids and is traditionally prepared and consumed in Southeast Asia, where it has been known to exhibit both painkilling and stimulant qualities, behaving as a μ-opioid receptor agonist, and often being used in traditional Thai medicine in a similar way to and often as a replacement for opioid painkillers like morphine.

Cinchona pubescens

Cinchona pubescens fruit is shown. Credit: United States Geological Survey.{{free media}}

General structure is of Cinchona alkaloids. Credit: Vaccinationist.{{free media}}

The bark of trees in this genus is the source of a variety of alkaloids, the most familiar of which is quinine, an antipyretic (antifever) agent especially useful in treating malaria. For a while the extraction of a mixture of alkaloids from the cinchona bark, known in India as the cinchona febrifuge, was used. The alkaloid mixture or its sulphated form mixed in alcohol and sold quinetum was however very bitter and caused nausea, among other side effects.

Cinchona alkaloids include:

• cinchonine and cinchonidine (stereoisomers with R¹ = vinyl, R² = hydrogen)
• quinine and quinidine]] (stereoisomers with R¹ = vinyl, R² = methoxy)
• dihydroquinine and dihydroquinidine (stereoisomers with R¹ = ethyl, R² = methoxy)

Alongside the alkaloids, many cinchona barks contain cinchotannic acid, a particular tannin, which by oxidation rapidly yields a dark-coloured phlobaphene called red cinchonic, cinchono-fulvic acid, or cinchona red.

In 1934, efforts to make malaria drugs cheap and effective for use across countries led to the development of a standard called "totaquina" proposed by the Malaria Commission of the League of Nations. Totaquina required a minimum of 70% crystallizable alkaloids, of which at least 15% was to be quinine with not more than 20% amorphous alkaloids.

Coffea arabica

Several coffee cherries grow along a branch; some are green and some are beginning to ripen. Credit: Forest & Kim Starr.{{free media}}

Phenolic acids and alkaloids in Coffea arabica: chlorogenic acid, syringic acid, ferulic acid, protocatechuic acid, hydroxybenzoic acid, caffeine, caffein acid, theophylline and trigonelline.

Coffea canephora

Immature Coffea canephora berries are on a tree in Goa, India. Credit: J.M.Garg.{{free media}}

Caffeine (1,3,7-trimethylxanthine) is the alkaloid most present in green and roasted coffee beans. The content of caffeine is between 1.0% and 2.5% by weight of dry green coffee beans. The content of caffeine does not change during maturation of green coffee beans. Lower concentrations of theophylline, theobromine, paraxanthine, liberine, and methylliberine can be found. The concentration of theophylline, an alkaloid noted for its presence in green tea, is reduced during the roasting process, usually about 15 minutes at 230 °C (446 °F), whereas the concentrations of most other alkaloids are not changed. The solubility of caffeine in water increases with temperature and with the addition of chlorogenic acids, citric acid, or tartaric acid, all of which are present in green coffee beans. For example, 1 g (0.035 oz) of caffeine dissolves in 46 ml (1.6 US fl oz) of water at room temperature, and 5.5 ml (0.19 US fl oz) at 80 °C (176 °F). The xanthine alkaloids are odorless, but have a bitter taste in water, which is masked by organic acids present in green coffee.

Trigonelline (N-methyl-nicotinate) is a derivative of vitamin B₆ that is not as bitter as caffeine. In green coffee beans, the content is between 0.6% and 1.0%. At a roasting temperature of 230 °C (446 °F), 85% of the trigonelline is degraded to nicotinic acid, leaving small amounts of the unchanged molecule in the roasted beans.

Coffea liberica

Excelsa coffee cherries are small and not uniform. Credit: Qomar nurusy syamsu.{{free media}}

Coffea racemosa

Coffea racemosa has naturally low levels of caffeine. Credit: Ton Rulkens.{{free media}}

"The basic genome, which is characteristic to most members of Rubiaceae family, is x = 11. The studied Coffea and Psilanthus species are all diploids that have 2n = 22 chromosomes, such as in C. liberica, C. robusta, C. kapakata, Coffea zanguebariae Lour., Coffea racemosa Lour., Coffea ligustroides S. Moore, Coffea mauritiana Lam., C. dewevrei, Coffea excelsa A. Chev., Coffea brevipes Hiern., Coffea congensis A. Froehner, Coffea stenophylla G. Don., and C. eugenioides [3]."

"In Coffea species, 5-caffeoylquinic acid (5-CQA) is the most abundant soluble ester. The beans of C. canephora contain feruloylquinic acids (3-, 4- and 5-FQA) and the isomers of monoester (3-, 4- and 5-CQA) and diester (3,4-, 3,5- and 4,5-diCQA) CQAs. Hydroxycinnamoylquinic acids are involved in the bitterness of coffee beverage due to their degradation into phenolics during roasting [17]. Additionally, various iridoid glycosides, tannins, and anthraquinones have also been detected in coffees [18]."

"Campa et al studied the presence of mangiferin and hydroxycinnamic acid esters in 23 African coffee leaves. They found that the total hydroxycinnamic acid content of C. arabica was significantly higher than that of other species (e.g. Coffea sessiliflora Bridson, Coffea resinora Hook.f., Coffea leroyi A.P.Davis), and mangiferin and isomangiferin were present in higher concentration in the young leaves than in other plant parts [21], [22]. Opposite to C. arabica and Coffea humilis A. Chev, feruloylquinic acids were present in higher amount in Coffea stenophylla and 3,4-dicaffeoylquinic acid were found in C. canephora. The caffeoylquinic acid content of the adult leaves of C. canephora was 10 times lower when compared to the young ones [17]. Coffea anthonyi Stoff. & F. Anthony and Coffea salvatrix Swynn. & Philipson presented higher concentration of mangiferin than C. arabica, C. eugenoides, Coffea heterocalyx Stoff., Coffea pseudozanguebariae (C. pseudozanguebariae), or Coffea sesiliflora Bridson [21], [23]."

"The presence of monoterpenoid alkaloids is characteristic to Rubiaceae family. In the synthesis of purine alkaloids, there are involved several enzymes such as caffeine synthase, xanthosine 7-N-methyltransferase, 7-methylxanthine 3-N-methyltransferase, caffeine xanthinemethyltransferase 1 (CaMXMT1), caffeine methylxanthinemethyltransferase 2 (CaMXMT2), caffeine dimethylxanthinemethyltransferase (CaDXMT1), and theobromine 1-N-methyltransferase [24]."

"The characteristic aroma of coffee is due to α-2-furfurylthiol, 4-vinylguaiacol, some alkyl and 3-methylbutane tyrosine derivatives, furanones, acetaldehyde, propanal, methylpropanal, and 2-a content [30], [31]. Cafesterol and bengalensol have also been isolated and identified by various chromatographic techniques in Coffea benghalensis [27], [32], [33]."

"Carotenoids, which are generally present in leaf, flower, fruit, and shoot of plants, play an important role in the stabilization of lipid membranes, the photosynthesis, and the protecion against strong radiation and photooxidative processes. Experiments with coffee species also showed that the transcript levels of enzymes involved in the synthesis of carotenoids increased under stress conditions [34]."

"The official drug is the seed (Coffeae semen) which contains 1.25%–2.5% caffeine (roasted seeds: 1.36%–2.85%), theobromine, theophylline, 4.4%–7.5% chlorogenic acid (roasted seeds: 0.3%–0.6%), 0.8%–1.25% trigonelline (roasted seeds: 0.3%–0.6%), 0.022% choline, 10%–16% fatty oil, quinic acid, sitosterol, dihidrositosterine, stigmasterol, coffeasterin, tannin, wax, caffeic acid, sugar, cellulose, hemicellulose, non-volatile aliphatic acids (citric, malic, and oxalic acid), volatile acids (acetic, propanoic, butanoic, isovaleric, hexanoic, and decanoic acids), soluble carbohydrates (e.g. monosaccharides: fructose, glucose, galactose, and arabinose), oligosaccharides: sucrose, raffinose, and stachyose, and polymers of galactose, mannose, arabinose, and glucose [30], [31], [38]. The concentration of caffeine, which occurs partially in free form or forms salt with chlorogenic acid, is reduced during roasting [39]. Theophylline is used as an important smooth muscle relaxant (in bronchospasms) in combination with ethylenediamine (Aminophylline) or choline."

"Coffee seeds are rich in biologically active substances and polyphenols such as kaempherol, quercetin, ferulic, sinapic, nicotinic, quinolic, tannic, and pyrogallic acids which possess antioxidant, hepatoprotective, antibacterial, antiviral, anti-inflammatory, and hypolipidaemic effects [41], [42], [43], [44], [45], [46], [47], [48], [49]. Besides the cis-isomers of chlorogenic acid in Arabic coffee [50], caffeic, chlorogenic, p-coumaric, ferulic, and sinapic acids, as well as rutin, quercetin, kaempferol, and isoquercitrine were detected in its fruit and that of Bengal coffee [51]."

"Isoquercitrin and rutoside extracted from coffee seeds that can be used for atherosclerosis, while quercitrin has positive chronotropic, positive inotropic, and antiarrhythmic effects, as well as protected LDL against oxidative modifications in guinea pig. Quercetin and rutoside have been used in the treatment of capillary fragility and phlebosclerosis [43]."

Mitragyna speciosa

Mitragyna speciosa leaves are featured. Credit: Uomo vitruviano.{{free media}}

Mitragyna speciosa (commonly known as kratom) is a tropical evergreen tree in the Rubiaceae (coffee family) native to Southeast Asia, indigenous to Thailand, Indonesia, Malaysia, Myanmar, and Papua New Guinea, where it has been used in herbal medicine since at least the nineteenth century. Kratom has opioid properties and some stimulant-like effects.

Uncaria rhynchophylla

Chemical structure is of rhynchophylline. Credit: Meodipt.{{free media}}

Rhynchophylline (methyl (7β,16E,20α)-16-(methoxymethylene)-2-oxocorynoxan-17-oate), methyl (2E)-2-[(1′R,6′R,7′S,8a′S)-6′-ethyl-2-oxo-1,2,2′,3′,6′,7′,8′,8a′-octahydro-5′H-spiro[indole-3,1′-indolizin]-7′-yl]-3-methoxyprop-2-enoate, is an alkaloid found in certain Uncaria species (Rubiaceae), notably Uncaria rhynchophylla and Uncaria tomentosa. It also occurs in the leaves of Mitragyna speciosa [family Rubiaceae] (kratom), a tree native to Thailand. Chemically, it is related to the alkaloid mitragynine.

Rhynchophylline is a non-competitive NMDA antagonist (IC₅₀ = 43.2 μM) and a calcium channel blocker.

Uncaria species have had a variety of uses in traditional herbal medicine, such as for lightheadedness, convulsions, numbness, and hypertension. These uses have been associated with the presence of rhynchophylline and have encouraged its investigation as a drug candidate for several cardiovascular and central nervous system diseases; however, few clinically relevant studies have been conducted.

Uncaria tomentosa

Chemical structure is of oxindole. Credit: Edgar181.{{free media}}

Skeletal formula is of sitosterol. Credit: Mysid.{{free media}}

Uncaria tomentosa is a woody vine found in the tropical jungles of South and Central America, known as cat's claw or uña de gato in Spanish because of its claw-shaped thorns. The plant root bark is used in herbalism for a variety of ailments, and is sold as a dietary supplement.

Phytochemicals in Uncaria tomentosa root bark include oxindole and indole alkaloids, glycosides, organic acids, proanthocyanidins, sterols, and triterpenes, tannins, polyphenols, catechins, and beta-sitosterol. It also contains rhynchophylline.

Individuals allergic to plants in the family Rubiaceae and different species of Uncaria may be more likely to have adverse reactions to cat's claw. Reactions can include itching, rash and allergic inflammation of the kidneys. People requiring anticoagulant therapy should not use cat's claw. Phytochemicals in cat’s claw may inhibit the liver enzyme, Cytochrome P450 3A4 (CYP3A4), which oxidizes organic compounds, and may interfere with the intended effect of prescription drugs.

β-sitosterol is widely distributed in the plant kingdom and found in vegetable oil, nuts, avocados and prepared foods, such as salad dressings.

See also

• Agronomy
• Alcohols
• Allergies
• Aquaculture
• Asteraceae
• Fabaceae
• Forestry
• Fruit and its importance
• Gene project
• Glandular system
• Hair colors
• Horticulture
• Human skin pigmentation
• List of plant family names
• Medicine
• Minerals
• Neutraceuticals
• Oils
• Pigmented lesions of the oromucosa
• Plants
• Polyphenols
• Pomology
• Terpenoids
• Vitamins
• Waxes