Rheum officinale, Baillon, palmatum, Linne', and var., or other species grown in China and Tibet. The dried rhizome and roots deprived of palmatum, periderm tissues, yielding not less than 30 p.c. of diluted alcohol-soluble extractive.

Habitat. W. And C. China, Thibet, Chinese Tartary; mountains, southern exposure -- light, loose, sandy and rich black forest soil.

Syn. Turkey or China Rhubarb; Br. Rhei Rhizoma; Fr. Rhubarbe de Chine; Ger. Rhizoma Rhei Rhabarber.

Rhe'um. L. Rha, the river Volga, upon whose banks it grows and was first found,fr. Gr.... pijov, peiv, to flow -- i.e., it causes purgation.

Of-fi-ci-na'le. L. officina, workshop; opus, work, + facere, to do -- i.e., used in or belonging to the shop or store.

Pal-ma'tum. L. palmatus, fr. palma, palm of the hand -- i.e., the much divided leaves.

Rhubarb, contraction of rheubarbarum -- rheum + barbarum, -- i.e., barbarian plant from the Rha (Volga), whence name rha Ponticum -- Pontic-rha, R. Rhaponticum, fr Pontic or Euxine Sea.

Plants

Large compact perennial herbs; aerial stem persisting through the winter, after a few years 30 Cm. (1 degree) high, 10-15 Cm. (4-6') thick, branches 25-37.5 Cm. (10-15') long, blunt summit, brown coat from withered scales (ocreas) and leaf-bases; internally fleshy (semi-[pulpy) with yellowish juice; leaves very large, petiole .3-.5 M. (12-18') long, 2.5-4 Cm. (1-1 3/5') thick, solid; lamina .6-1.3 M. (2-4 degrees) long and broad, suborbicular, palmately-veined, 5-7-lobed, reticulate, pubescent, pale green; stipules very large; flowering branches (stems) several, 1.5-3 M. (5-10 degrees) high, hollow, thick, green, striate, smoothish; flowers May-June, 6 Mm. (1/4') long, clusters of 7-10, catkin-like compound panicles, greenish-white; fruit August, small clusters, 12 Mm. (1/2') long, 6 Mm. (1/4') broad, triangular, wing at each angle, crimson-red; seed solitary.

Rhizome

subcylindrical, barrel-shaped, conical, rounds, or flattened pieces, flats, frequently with a perforation; hard, moderately heavy, 5-17 Cm. (2-7') long, 4-10 Cm. (1 3/5-4') thick, or cut into variable shape and size; yellowish-brown, with lighter striations and occasional small patches of brown cork, more or less covered with yellowish-brown powder; fracture uneven, stellate vascular bundles, granular yellowish mottled surface; odor aromatic, agreeable; taste bitter, astringent, gritty when chewed, tingeing saliva yellow.

Powder

yellowish-brown -- calcium oxalate rosette aggregates, starch grains .004-.025 Mm. (1/6250-1/1000') broad, few tracheae, reticulate and spiral. Tests: 1. Boil .1 Gm. with aqueous solution of potassium acid, shake with ether 10 cc.; ethereal layer (yellow on standing) shaken with ammonia T.S. 5 cc. -- ammonia layer cherry-red color (pres. of emodin) , ethereal layer remains yellow (pres. of chrysophanic acid). 2. Boil 1 Gm. + diluted alcohol 50 cc. for 15 minutes under a reflux condenser, filter, evaporate to 10 cc., cool, shake with ether 15 cc., set aside for 24 hours -- yellowish prismatic crystals should not form (abs. of rhapontic rhubarb). Solvents: alcohol; water. Dose, gr. 5-30 (.3-2 Gm.)

Adulterations

Irrespective of variety, rhubarb should be moderately heavy, compact, bright color, brittle, broken edges with fresh appearance, red and yellow veins intermingled with white, decidedly aromatic odor, bitter, astringent, slightly gritty, non-mucilaginous, staining saliva yellow; pieces that are porous, mucilaginous taste, dark brown interior should be rejected. Turmeric sometimes added to the powder and also rubbed over unsightly pieces-recognized by its starch grains, as well as by adding to 5 gr. (.3 Gm.) of suspected rhubarb a few drops of chloroform on white peper, when Chinese slightly stains the paper, while the European, or dark-colored Chinese, imparts a deep yellow stain; now on adding a few grains of borax + a drop of hydrochloric acid, if pure rhubarb--stain not changed, if tumeric present--get a distinct red.

Commercial

Plants, resembling our garden rhubarb -- pie-plant, grow wild and largely under cultivation in Chinese Empire, where a number of species, chiefly the two recognized, furnish the official product. Rhizome, when 8-10 years old, is dug in the autumn (Tartary, spring, China, Sept.-Oct.), and, after removing roots and corky layer, is divided into segments (to aid drying), perforated, strung on cords, and suspended in the shade or under cover (house roofs and eaves) to be cured by circulating air, a process that often requires a year and a loss of 80 p.c.; frequently that dried by the sun, heated stones, stoves, ovens, kilns, or brushwood fires, high dried (usually having broad ridges, blackish grooves, heavy disagreeable odor) and the larger roots, tails, are included, but both are more or less inferior. Variety and quality are distinguished, in experienced hands, by odor (bouquet), while all kinds are subject to insect attack, which is prevented best by keeping in tightly-closed containers having a tuft of cotton saturated with chloroform or carbon tetrachloride. Most of our supply comes from Hankow, on the Upper Yangtse, that from Hsining (Tzechuen and Shensi products) commanding the highest price. There are three varieties: 1, Russian (Turkish Crown -- R. palmatum), no longer on the market, but consisted of the best rhizome, from Chinese Tartary via Siberia, trimmed to beneath the cambium, perforated with large conical hole (for easy examination), inspected rigorously at Kiachta, refuse burned, the reserve sewed in linen sacks, covered with hide, and sent to Leningrad (Petrograd St. Petersburg); Turkish ports once suppled it (hence name), being brought from Tartary by caravans through Persia and Anatolia; 2, Chinese (E. Indian -- R. officinale, R. palmatum, var. tanguticum, etc.), our official rhizome, having inner bark, and sometimes patches of rough corky layer and twine fibers; color less bright and odor less aromatic than Russian; flourishes best at 2,400-3,000 M. (8,000-10,000 degrees) elevation in the Himalaya and other mountains, on the shady side of damp ravines, with northern exposure; distinguished natively as "northern" and "southern," also as "Shensi" (best, most expensive -- orange color, agreeable odor), "Canton" (smoky odor, bitter, ochre-yellow), "Shanghai" (smoky odor, light yellow; exported chiefly from Canton, occasionally via India; 3, European (Rhaponticum--R. palmatum, R. rhaponticum, R. compactum, R. undulatum, R. emodi +), cultivated in England, France, Austria (Moravia), the rhizome being cut to resemble the Chinese, but differing in having the outside nearly or entirely without white meshes, the medullary rays interrupted, narrow, nearly straight, with paler color, weaker odor, and less gritty but more mucilaginous taste; rarely imported.

Constituents

Resin, Aloe-emodin, Chrysophanic acid, rhein, emodin, emodin monomethyl ether, rheinolic acid (new anthraquinone derivative), volatile oil, rheotannic acid, gallic acid, cinnamic acid, palmitic acid, stearic acid, oleic acid, linolic acid, verosterol (phytosterol), dextrose, levulose, calcium oxalate 2-40 p.c. (the greater the amount, the greater the activity of the drug, the two going hand in hand); starch, ash 12-13 p.c. -- very inferior 35-45 p.c.

Resin. -- Chief purgative principle; amorphous, non-glucosidic -- obtained from alcoholic extract, after removing volatile oil, by separating from greenish-yellow residue in still the dark aqueous liquid, extracting it with ether, then with amyl alcohol, evaporating to get brown tarry liquid and yellowish granules, crystals (aloe-emodin, chrysophanic acid, rhein, emodin, emodin monomethyl ether, rheinolic acid -- all of which the resin yields upon hydrolysis); evaporate brown tarry filtrate, dissolve in alcohol and precipitate with equal quantity of chloroform.

Aloe-emodin and Chrysophanic Acid. -- Both slightly purgative, obtained by concentrating above ethereal liquid, heating residue with ethyl acetate, adding petroleum, decanting from tarry precipitate, evaporating petroleum solution, dissolving in ether, extracting with 10 p.c. aqueous solution of sodium carbonate (aloe-emodin), or with 10 pc. aqueous solution of potassium hydroxide (chrysophanic acid). Aloe-emodin is the rhabarberon and iso-emodin of some writers.

Preparations

1. Extractum Rhei. Extract of Rhubarb. (Syn. Ext. Rhei., Powdered Extract of Rhubarb, Extractum Rhei Alcoholicum; Fr. Extrait de Rhubarbe; Ger. Rhabarberextrakt.)

Manufacture

Macerate, percolate 100 Gm. with 80 p.c. alcohol until exhausted, reclaim alcohol, continue distillation until residue syrupy consistence, transfer to a dish, rinse still with little warm menstruum, which add to dish and evaporate to dryness at 70 degrees C. (150 degrees F.), stirring frequently; add dried starch enough for extract to weigh 50 Gm., pulverize, mix thoroughly, pass through fine sieve; 1 Gm. represents 2 Gm. of the drug. Should be kept in small, wide-mouthed tightly-stoppered bottles. Dose, gr. 3-10 (.2-.6 Gm.).

2. Fluidextractum Rhei. Fluidextract of Rhubarb. (Syn., Fldext. Rhei, Fluid Extract of Rhubarb; Fr. Extrait fluide de Rhubarbe; Ger. Rhabarberfluidextrakt.)

Manufacture: Similar to Fluidextractum Sarsaparillae, page 126;

Preps.: 1. Syrupus Rhei. Syrup of Rhubarb. (Syn., Syr. Rhei; Fr. Sirop de Rhubarbe; Ger. Rhabarbersirup (saft).)

Manufacture

10 p.c. Mix fluidextract of rhubarb 10 cc., spirit of cinnamon .4 cc., add potassium carbonate 1 Gm., dissolved in water 5 cc., and to this mixture add syrup q.s. 100 cc. Dose, 3j-4 (4-15 cc.).

2. Mistura Rhei Alkalina, Neutralizing Cordial, N.F., 1.6 p.c.

3. Mistura Rhei Composita, Mixture of Rhubarb and Soda, N.F., 1.5 p.c. 4. Elixir Catharticum Compositum, N.F., 6.2 p.c.

3. Pulvis Rhei Compositus. Compound Powder of Rhubarb, (Syn., Pulv. Rhei Co., Gregory's Powder, Powder Magnesia and Rhubarb, Pulvis (Infantum) Antacidus; Fr. Poudre de Rhubarbe composee; Ger. Pulvis Magnesiae cum Rheo, Kinderpulver.)

Manufacture

25 p.c. Triturate together rhubarb 25 Gm., ginger 10, add gradually magnesium oxide 65; mix thoroughly, pass through No. 60 sieve. It is pinkish-white, mobile, darker on exposure to moisture; it exhibits fine particles of magnesiium oxide, numerous elliptical starch grains (ginger), .005-.06 Mm. (1/5000-1/400') broad, and fragments of vegetable tissues; polygonal starch grains (rhubarb), .002-.02 Mm. (1/12500-1/1250') broad. Dose, 3ss-1 (2-4 Gm.).

4. Tinctura Rhei, Tincture of Rhubarb. (Syn., Tr. Rhei; Fr. Teinture de Rhubarbe; Ger. Rhabarbertinktur.)

Manufacture: 20 p.c. Similar to Tinctura Veratri Viridis, page 104; 1st menstruum: glycerin 10 cc., alcohol 50, water 40, 2d: diluted alcohol q.s. 100 cc. Dose 3ss-4 (2-15 cc.): Prep.: 1. Mistura Opii et Rhei Composita, N.F., 10 p.c.

5. Tinctura Rhei Aromatica. Aromatic Tincture of Rhubarb. (Syn., Tr. Rhei Arom.; Fr. Teinture de Rhubarbe aromatique; Ger. Aromatische Rhabarbertinktur.)

Manufacture

20 p.c. Similar to Tinctura Veratri Viridis, page 104 -- using rhubarb 20 Gm., cinnamon 4, clove 4, myrstica 2; 1st menstruum: glycerin 10 cc., alcohol 50, water 40, 2d: diluted alcohol q.s. 100 cc. Dose, 3ss-4 (2-15 cc.).

Prep.: 1. Syrupus Rhei Aromaticus. Aromatic Syrup of Rhubarb. (Syn., Syr. Rhei. Arom., Spiced Syrup of Rhubarb; Fr. Sirop de Rhubarbe aromatique; Ger. Gewurtzer Rhabarbersirup (saft).)

Manufacture

3 p.c. Dissolve potassium carbonate .1 Gm. in aromatic tincture of rhubarb 15 cc., to this add syrup q.s. 100 cc. Mix thoroughly. Dose, for a child with diarrhea, 3j-2 (4-8 cc.).

6. Fluidglyceratum Rhei, N.F. 7. Pilulae Rhei, N.F., 3 gr. 8. Pilulae Rhei Compositae, N.F., 2 gr. 9. Pulvis Rhei et Magnesiae Anisatus, Compound Anise Powder, N.F., 35 p.c. 10. Tinctura Rhei Aquosa, N.F., 10 p.c. (11 p.c. alcohol). 11. Tinctura Rhei Dulcis, N.F., 10 p.c., 1st menstruum: glycerin 10, alcohol 50, water 40, 2d: diluted alcohol. 12. Tinctura Rhei et Gentianae, N.F., 7 p.c., + gentian 1.75 p.c. (diluted alcohol). 13. Pilule Antiperiodicae, N.F., ½ gr. 14. Syrupus Sennae Aromaticus, N.F., 1.75 p.c. 15. Tinctura Antiperiodica, N.F., 4/5 p.c. Dose, each, 3ss-2 (2-8 cc.).

Unoff. Preps.: Aromatic Fluidextract, mxv-60 (1/4 cc.). Infusum Rhei (Br.), 5 p.c., 3iv-8 (15-30 cc.). Liquor Rhei Concentratus, 50 p.c., 3ss-1 (2-4 cc.). Vinum Rhei Compositum, 8 p.c., +, 3j-4 (4-15 cc.). Torrefied Rhubarb. -- By roasting, the cathartic principle is volatilized and the full astringency left behind; long boiling will effect the same result.

Properties

Aperient, purgative, astringent, stomachic, tonic. It increases saliva, gastric juice, bile, peristalsis, vascularity, and absorption. The cathartic effect comes first (4-8 hours), due to resins (mainly pheoretin), emodin, etc.; then follows astringency from rheotannic acid; both actions being chiefly on the duodenum. The milk, urine, and sweat become colored, the first also acquiring bitterness and purgative properties. Purgation may result from its application to ulcers, abraded skin, or in poultices to abdomen.

Uses

Diarrhea, hemorrhoids, cholera infantum, chronic dysentery, dyspepsia, thread worms. With calomel good in bilious fevers; with magnesium oxide for stomach and bowel disorders. By association with other cathartics both rendered more efficient; sometimes used with opium.

Allied Plants

1. Rheum rhapon'ticum. Asia Minor, Siberia, Russia. This is cultivated as pie-plant, the leaf-petioles being used, as they possess pleasant acidulous properties; this species is the source of the cultivated European rhizome, and that of Moravia (Austria), Hungary, England, and Banbury, which is usually less than half the size of official rhubarb, conical, harder, lighter color, more bitter and astringent, less gritty; contains rhapontin, CHO.  R. undula'tum, R. compac'tum, R. Emo'di, R. austra'le, R. hyb'ridum. -- All produce handsome, but smaller, less valuable, and lighter-colored rhizomes.