CAIECHU

Garnbil or pale catechu of the BP 19891' BP (Vetelinary), 2000 is adried, aqueor"rs extract prepared fiom the leaves and young twigs of aclirnbing shrtb, Uncuria ganrbir (RLrbiaceae). It must be carefully dis-tinguished from black catechu or cutch. The plant is a native of Malayaand it is largely cultivated lor the prodr.rction of the drug in Indonesiaand Malaya fbr rnarketing throu-gh Singapore.

History. The catechr-r described by Barbosa (1514) was black cat-echu or cutch. and the first account of gambir appears to be that of aDutch trader in 1780. ln trddition to the cube garnbir used in pharmacy,lalge blocks of the extlact are imported fbr use in dyeing and tanning.Other fbrrns are used in the East fol chewing with betel leaf.

Preparation. The preparation of catechu in Johole diff'ers onlyslightly fiom the procedure adopted in Indonesia. It consists of extract-ing the leaves and young twigs with boiling water, evaporatin-q theextract to a pasty consistency and dividing it into cubes. which are thensun-dried. Fuller details of the preparation are given in the I Oth edition.

Many difl'elent fbrms of catechu are used in the East, and the drugfor the Eastern market fiequently has 20 50rlc of fine rice husks addedas the liquid coagulates in the tubs. Such catechu is. o1'course. r.rnoftl-cial. and contains starch.

Macroscopical characters. Catechu occurs in cubes. which are verytiiable and may be broken up in transit or, if incompletely dried, may bemore or less agglutinated. Of the samples available, those fromIndonesia measure ll-22 nn and have a reddish-brown surface. oltenstamped with a maker's mark. while those liom Johore measure 21-29mrr and have a blackish extedor and the laces of the cube are depressed.Internally. both varieties are cinnamon-brown and porous. Odourless;taste. very astringent trnd at first somewhat bitter, afterwards sweetish.

Microscopical characters, When mounted in wateq catechu showsminute. acicular crystals of catechin. many of which are branched andinterlacing. They dissolve on warming and a considerable amount ofvegetable debris is left. The leaves. particularly the stipules, bear simple,unicellular hairs up to about 3,50 ptm long. with sn.rooth. moderately thick.lignified walls. The twigs have lignified pericyclic fibres. wood fibres,and spiral, annular and pitted vessels. Minute sftLrch grains are commonlypresent, pafticularly in the lndonesian drug, but the amount should bestrictly limited. Rice husks have been observed in some samples.

Chemical tests

(l) For gambir-.fluorestitt. Extract a little of the powdered dm-9 with alco-hol and filter. To the hltrate add solution of sodium hydroxide. Aftershaking, add a f-ew millilitres of light petroleum. shake again and allowto stand. The petroleum spirit layer shows a sffong green fluorescence.

(2) For c'atechin. This is a rnodification of the usual test fol lignin.Phlorogiucinol is lbrmed fiom catechin and with hydrochloric acidturns a matchstick red.

Constituents. Gambir contains abou 7 .33% of catechins. 22-50c/oof catechutannic acid, catechu red. quercitin and gambir-f'luorescin.

BP (Vet.) 2000 standards inclr-rde a loss on drying of not more than15.0% and a water-insoluble matter of not more than 33.07c with ref'er-ence to the dried material.

Catechin tblms white. acicular crystals which are soluble in hot waterand alcohol and give a green colour with ttnic salts. Catechutannic acidis an amorphous phlobatannin which appears to be fomed fiom catechin

PHENOLS AND PHENOTIC GLYCOSIDES

by loss of the elements of water. It readily yields the phlobaphene cate-chu-red. If the drug is caretully prepared, it r.vill contain a high proportionof catechin and conespondingly srnaller amounts of catechutannic acidand catechu-red.

Aflied drug. CLrtch or black catechu is an extract prepared from theheartwood of Acacicr catechu (Leguminosae). Cutch occurs in black,somewhat porous masses. The taste resembles that of gambir.Microscopical examination of the water-soluble residue shows woodtlbres and large vessels and sometimes fragments derived fiom theleaves on which the drug is spread.

Cutch contains 2 12Vc of catechins. 25-33c/a of phlobatannin,20-3OVo of gummy matter, quercitrin. quercitin. moisture, etc. lt yields2-3c/c ol ash. The catechin (acacatechin) is not identical with that ingambir. The drug may be distinguished from gambir as it gives no reac-tion for gambir-fluorescin.

Uses. Catechu is used in r-nedicine as an astrinsent.

KinosThe name 'kino'has been applied to a nun.rber of dried juices, rich in phio-batannins zurd formerly used fbr their astringent propenies. They includeMalabar kino from Pterocarpus marsupiurn (Legunrinosae). butea gumor Bengal kino from Butea .frondosa (.8. morutspennn) (Legurninosae)and eucalyptus kino or red gr-rm from EucalyptLts tostroto ( Myrtaceae).

Crolon lechleriThe b:irk of this and related euphorbiaceous trees yield, when slashed. ablood-red sap commonly known in South American folk medicine asSangre de Grado, Sangre de Drace, or dragon's blood (not to be confusedwith the dragon's blood obtained from species of Daemonorops palms.q.v.). It is used locally for its anti-int-ective, antitumour and wound healingpropefiies. Cai er al. (Phytochemi.sttl'. 1991, 30, 2033; 1993,32. 155)have shown proanthocyanidins to be the principal constituents (c'.90c/r)which vary fiom monomers to heptamers. These polyphenols possessoxygen free-radical scavenging activity and may assist in wound healing(C. Desmarchelier et al., J. Ethnophnrmacology. 1997, 58, 103). Minorcomponents isolated are phenols, alcohols, sterols and four diterpenoids,two of the latter being of the clerodane type. An alkaloid, tapsine, has beenascribed as the wound healing constituent; it could also account for theantitumour activity claimed for the latex (2. Chen et al., Pltutta Medica,1994.60 .541) .

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rcoumARNSr AND,GIYCOS|DES,,,

Derivatives of benzo-o-pyrone such as coumarin (the lactone of O-hydroxycinnan-ric acid), aesculetin. umbelliferone and scopoletin arecommon in plants both in the free state and as glycosides. Not all are phe-nolic br.rt they are included here with the phenolic derivatives for con-venience. Some 1000 natural coumarins have been isolated. Coumarinitself has been found in about I 50 species belonging to over 30 diff'erentfamilies, although it is probably present in the undamaged plant as /rrars-O-glucosyloxycinnamic acid. Enzyme activity in the damaged tissueleads to a loss of glucose and a trans -+ cis isomerization foliowed byring closure. Coumarin gives a characteristic odour of new-mown hayand occurs in many Leguminosae such as sweet cloveq melitot and toncobeans: the latter contain about l-37c of coumarin. It is also recorded inu'oodruff. A.rpe r Ltl a o do ruta (Rubiaceae).

In ammoniacal solution these compounds have a blue, blue-green orviolet fluorescence, which has long been used as a qualitative test for

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