VOLATILE OIL FROM THE LEAVES OF UAROS&IA VENUSTA. 2613CCXL1V.- Volcctile Oil from the Leaves o j ’ Barosmavcnusta.By ERNEST GOULDING and 0 s WALD DIGBY ROBERTS.THE genus Barosmu, of which about thirty species exist in SouthAfrica, derives its chief iniportance from the fact that certainspecies yield the so-called Buchu leaves, which are employed inmedicine as mild disinfect,ants of the urinary tract. The physio-logical activity of the leaves is principally due to the volatile oilwhich they contain. The source of Buchu leaves of the BritishPharmocopoeia, or short Buchu,” is Barosma betzdina, Bartl. andWendl., but the leaves of 13. creizulata, Hook. and B. s e w a t i f o h ,Willd., are also met with in commerce under the name of “longBuchu.”Another species of Barosma, 13.uenusta, Eckl. and Zeyh., occursin considerable quantities in the Uitenhage District of t’he CapeProvince. Information was desired in South Africa as to thepossible value of the leaves of this plant in comparison with BuchuVOL. cv. 8 2614 GOULDING AND ROBERTS: VOLATILE OIL FROM THEleaves, and an examination of the material was therefore under-taken a t the Imperial Institute.The most characteristic constituent of the oil of Barosma betalinais diosphenol, which is present in quantities of 20-30 per cent.;the oils of B, menulata and B. serratifolia, however, contain only avery small proportion of this substance. The' results of the presentinvestigation show that the oil of B. venusta differs very consider-ably in odour and composition from that of Buchu leaves, andthat it does not contain any diosphenol.I n 1911 a sample of the leaves of Barosma venusta was receiveda t the Imperial Institute from the Cape Province, South Africa.On distillation in a current of steam it yielded 2.7 per cent.of avolatile oil, which was of a lemon-yellow colour and pleasant odour,and had D15 0.877 and a: 1°4' in a 100-mm. tube.A larger consignmenb of the leaves, forwarded in 1913, fur-nished 2.0 per cent. of volatile oil with the following constants:DI5 ............................................................ 0.865a y in 100 mm. tube ....................................... +0°47'Acid value ................................................... 6.6Ester value ................................................ 6.2(Corresponding with 2.2 per cent.of esters, calculated88 C,,H,,*OAc.)Ester value after acetylation ........................ 55(Corresponding with 15.7 per cent. of total alcohols,or 14-3 per cent. of free alcohols and 2.2 per cent.of esters.)Fractional Distillation of the Oil.On distilling the oil under atmospheric pressure the followingfractions were obtained, but some decomposition occurred :Fraction. Per cent. Boiling point. DI5. aD in 100 mm. tubeI. 44 163-190" 0.8100 inactive.11. 17 190-205 0.8932 inactive.111. 28 205-230 0.9531 + O"30'IV. 9 230-246 0.9610 liquid too dsrn-coloured to admitof this determina-tion.- - - Residue 2Isolation and Identification of Myrcene.When a portion of the oil was distilled under 60 rnm.pressure,about 48 per cent. collected between 83O and 88O. This fraction,after being treated repeatedly with sodium and redistilled, hadD15 0.8060, and was optically inactive; it distilled a t 163-173Ounder atmospheric pressure, but suffered partial decompositionLEAVES OF BAROSMA VENUSTA. 2615This hydrocarbon exhibited the properties characteristic ofmyrce,ne, for which the following constants have been recorded :Power and Kleber .................. D15 0.8023 b. p. 167".Chapman .............................. DI5 0.8046 b. p. 166-168".Enklaar4 ................................. D15 0.8013 b. p. 166-168".Phnrm. ItundscR., 1895, 13, 61.T., 1903, 83, 507.Semmler - b. p. 171-172'. ..............................Semmler and Mayer5 Dm 0.7937 - ...............Ber., 1901, a, 3216.Diss., Utrecht, 1906.Ber., 1911, 44, 2010.The terpene showed a great tendency to resinify, and readilycombined with four atoms of bromine.On reduction with sodiumand alcohol it was converted into a compound having D15 0.7860,a value which agrees well with those recorded for dihydromyrcene,namely, 0.7802 and 0.7852, by Semmler (Zoc. cit.) and Enklaar(Zoc. cit.) respectively. This reduction product furnished a tetra-bromide, melting a t 9l0, which crystallised from methyl alcohol inhard, white needles. The melting point of dihydromyrcene tetra-bromide has been given as 87O by Semm'ler and Mayer (Zoc. cit.)and 8 8 O by Enklaar (Zoc. cit.). By the action of a mixture ofglacial acetic acid and sulphuric acid on the original terpene, anacetate was obtained which resembled linalyl acetate in odour, and,on hydrolysis, yielded an alcohol.This alcohol, when oxidised withchramic acid, did not furnish citral, but the odour of the productsuggested the presence of some other aldehyde. These observationsaccord with those of Barbier (Compt. rend., 1901, 132, 1048) onthe oxidation of myrcenol. The existence of myrcene in the oil istherefore established.Aldehydes : Identification of Anisaldehyde.A portion of the oil was shaken with solution of sodium hydrogensulphite. After the aqueous liquid had been separated and washedwith ether, it, was readered alkaline by the addition of sodiumhydroxide, and extracted by repeated agitation with ether.Theethereal solution was dried with anhydrous sodium sulphate, andthe ether was removed by distillation, The residue, amounting t oabout 0.5 per cent. of the original oil, appeared from its taste andodour to consist chiefly of anisaldehyde, and, on oxidation withpotassium Fermanganate, was readily converted into anisic acid,which after recrystallisation melted a t 183-184O (anisic acid hasm. p. 184O).8 H 2616 VOLATILE OIL FROM THE LEAVES OF RAROSMA VENUSTA.dlcoliols : Itrdicntioti of the Presetzce of Liriulool.The fraction boiling atd 190-205° under atmospheric pressureconsisted largely of alcohols, and had a sweet odour resemblingthat of linalool; on oxidation i t yielded citral, which was charac-terised by its odour and by the preparation of a-citryl-P-naphtha-cinchoniiiic acid, melting a t 1 9 9 O .It is therefore proba,ble that thealcohols consish in part, of linalool.I'hetiols : A-l b s r t i c r of lliosplieml.When the original oil, after being washed successively withsodium carbonate solution and sodium hydrogen sulphite solutionto remove acids and aldehydes, was treated with 5 per cent.solution of sodium hydroxide, an absorption amounting t o only0.2 per cent. took place. On acidifying the solution and extractingwith ether, a phenolic substance was obt'aiiied, but in too small aquantity t o admit of investigation; this product did not give anydistinctive coloration with ferric chloride. No evidence could beobtained of the presence of diosphenol.Ethers : ITdeiz,fification of illethylchauicol.A fraction of the oil, boiling a t 213--218O, was found to consistof methylchavicol, which was identified in the following way.The fraction was heated with 20 per cent.alcoholic potassiumhydroxide solution for two days in a sealed €ube at ZOOo. Thecontents of the tube were diluted with water and extracted withether. After drying the ethereal solution with anhydrous sodiumsulphate, and removing the &her by evaporation, i t was foundthat the oil had been convert'ed alniost quantitatively into anethole,which boiled a t 232-234O, and solidified on cooling to a mass ofcrystals, melting at 2 2 O . The product possessed the' odour andsweet taste characteristic of anethole.Determinations of methoxylin the origiiial oil gave results indicating the presence of 21.4 percent. of methyl ethers (calculated as methylchavicol) :0.2770 gave 0.0947 AgT. OMe =4*51 or CgHg-OMe= 21.5 per cent.0.2895 ,, 0.0980 AgI. OMe=4.46 ,, C9Hg*OMe=21*3 ,, ,,Constituents of High Boiling Point.The fraction which distilled a t 230-245O was brownish-yellow,viscous, and had a somewhat empyraumatic odour; it probablycontained sesquiterpenes, together with polymerides and decom-position producte of myrcene, due to the high temperature t o whichit had been heate,dVANSTONE : SODIUM AMALGAMS. 2617Sicntmnry of Results.The results of this investigation indicate that the volatile oil ofBarosma venusta leaves has approximately the following com-position :Per cent.Hydrocarbons, chiefly or entirely myrcene .................. 43.0Phenols .................................................................. 0.2Phenol ethers, methylchavicol .................................... 21.414.3Esters (calculated as C,,H,;OAc) ................................. 2.2Sesquiterpenes, loss, etc. (by difference) ..................... 18.4I n conclusion, reference may be made t o an examination ofthis oil by Jensen (Pharm. J., 1913, [iv], 36, 60). Although theleaves from xhich he distilled tqhe oil were obtained from the, samesource as those used in the present investigation, t,he results showcertain differences, of which the1 most remarkable is that he1 found16 per cent. of chavicol, whereas the authors have not been ableto detect the presence of even a trace of this phenol.............. Aldehydes, 9 9 ,, ,, anisaldehyde.. 0.5Alcohols, partly linalool (calculated as C,,,H,,'OH) .........The authors desire t o express their thanks to Mr. J. C. Earlfor much valuable assistance in the pre,liminary stages of thisinvestigation.SCIENTIFIC AND TECHNICAL DEPARTMENT,1 bI PERIAL INSTITUTE, 8. w