3 MYRRH – COMMIPHORA CHEMISTRY

Myrrh and opopanax has been used throughout history in incense and as a perfume. Since Bible times it has been used for the treatment of wounds. The first attempts to identify content compounds were almost 100 years ago. In this review we discuss the present state of knowledge in the chemistry of substances of Commiphora spp.


INTRODUCTION
Myrrh and the similar but lower quality opopanax are the hardened, resinous exudates obtained from trees of certain Commiphora species of the Burseraceae family.Myrrh and opopanax oils are occasionally used as flavouring agents.Somalia and Ethiopia are by far the largest producers of the two resins.Northern Somalia is the world's largest source of incense and myrrh, which are forestry products.Aromatic flora, producing frankincense and myrrh, are indigenous to the mountain slopes.Somalia supplies most of the world's myrrh and opopanax (about 1 500 tonnes in 1987).The People's Republic of China is the largest market for all two resins, mainly for use in traditional medicines.In early 1994, clean Somali myrrh was available at US $ 5/kg.Somali opopanax was priced at US $ 3.50/kg (clean) and US $ 3.00/kg (natural).
Commiphora species are small trees or shrubs with short, thorny branches.True myrrh is produced by C. myrrha, a variable species found in southern Arabia and northeast Africa (chiefly Somalia) as far south as northeast Kenya.Other resin-producing Commiphora occur in southern Arabia, Sudan, Ethiopia, Eritrea, Somalia and Kenya.C. erythraea and C. kataf, the main sources of opopanax, are abundant in many parts of southern Arabia, Somalia, eastern Ethiopia and Kenya.
In Arabic the word murr means "bitter", it has been used throughout history in incense and as a perfume.It is said that the Greek soldiers would not go into battle without a poultice of myrrh to put on their wounds.It is often used in toothpastes and in the perfume industry.It tends not to dissolve very well in water however.
Myrrh consists of water-soluble gum, alcohol-soluble resins and volatile oil.The gum contains polysaccharides and proteins, while the volatile oil is composed of ster-oids, sterols and terpenes.Myrrh's characteristic odor is derived from furanosesquiterpenes.
Since Bible times it has been used as a medicine and wound dressing and has been closely associated with the health and purification rituals of women.It was first described in the Chinese medical literature.The use of myrrh medicinally was recorded in China in A.D. 600 during the Tang Dynasty.Myrrh is used today in Chinese medicine to treat wounds, relieve painful swelling, and to treat menstrual pain due to blood stagnation.Myrrh is called mo yao in China.It has long been used in the Ayurvedic system of medicine.
Commiphora opobalsamum balm is the thickened gum from the juice of the balsam tree, which was abundant in Judea.It is native to southern Arabia and Abyssinia, was cultivated on the plains of Jericho and the Jews believed it was planted by King Solomon.According to history the Queen of Sheba brought balm to Solomon on the occasion of her visit.Balm was rare and costly when exhibited in Rome for all people to see.After the conquest of Judah, it was brought by Pompey for display.When Vespasian destroyed Jerusalem, balm was among his spoils.Balm was the emblem of Palestine and newly cultivated shrubs were protected by sentries.

General
On this place we must mention the most known Commiphoras, namely Commiphora myrrha (Nees) Engl., true myrrh, officinal myrrh, Heera Bol tree; C. myrrha (Nees) Engler var molmol Engler (C.molmol Engl.ex Tschirch), Somalian myrrh; Commiphora abyssinica (Berg) Engler (syn.Commiphora madagascarensis Jacq.), Arabian myrrh, Abyssinian myrrh; Commiphora africana (A.Rich.)Engl., myrrh, African bdelium; Commiphora guidottii Chiov., sweet myrrh, habag-hady (name in Somalia); Biomed.Papers 149 (1), 3-28 (2005 The following new species were described by Thulin 2 : Commiphora arenaria from bushland on sand in south-central Somalia, C. gardoensis from limestone slopes in the Qardho area in north-eastern Somalia, C. stellatopubescens from bushland on limestone outcrops or stony ground in the Hiiraan Region in south-central Somalia, C. spinulosa from limestone rocks on the escarpment along the Gulf of Aden in northeastern Somalia, C. lobatospathulata from bushland on sand in central and southcentral Somalia, C. quercifoliola from bushland on shallow soil over limestone near Eil in north-eastern Somalia, C. chiovendana from bushland in northern and central Somalia, C. multifoliolata from limestone hills and ridges in south-western Somalia, C. murraywatsonii from limestone outcrops near Hobyo in central Somalia, and C. kucharii from bushland on shallow soils over limestone in central and southern Somalia. The next publication goes further to inform as about present state of distribution of Commiphora spp.(ref. 3) Commiphora myrrha is the chief source of myrrh today, but C. erythraea was the principal source of ancient and classical time.A number of oleo-gum-resins called bdelliums are produced in Arabia and Somalia from various species of Commiphora and resemble myrrh; these were probably counted as myrrh in classical times and are probably used for adulteration today.The "perfumed bdellium" (opopanax or bisabol myrrh) is from C. erythraea.Myrrh is employed by perfumers as an absolute, oil, or resinoid.Myrrh is included in the formulations of a number of modern perfumes, is used by many herbalists as an astringent for the mucous membranes of the mouth and throat.
In order to collect gum, the natives make incisions into the bark, causing the exudation of a yellowish oleoresin.Exposed to the air, this dries, hardens and turns reddish-brown.
Myrrh is partly soluble in ethanol (∼ 30 % alcoholsoluble material) and is also partly soluble in water and in ether.Since antiquity myrrh has served as a constituent of incense.Oil of myrrh is a valuable ingredient in perfumes (balsamic, heavy odour).
2-acetoxyfuranodiene 24 and 2-methoxyfuranodiene 25 were isolated from chloroform extract of ground myrrh (commercially available) with the help of flash chromatography by Monti 18 .The absolute configuration of these compounds was determined.
Ma et al. (ref. 19) described an analytical supercritical fluid extraction (SFE) system and its application to GC/ MS of frankincense and myrrh, Chinese medicines.The result shows that analytical SFE is a more afficient technique for investigating Chinese medicine compounds.In addition the information generated supplements to the available literature on title medicines and revealed its potential application in the compound study of the Chinese herbal medicine.
The constituents of the supercritical fluid extraction and the steam distillate of myrrh and Curcuma zedoaria, two Chinese herbal medicines with the help of GC/ITD studied Yu 20 .Fourty one and 45 compounds were identified, respectively, in myrrh and C. zedoaria which were mainly sesquiterpenoids and furanose sesquiterpenoids.The feature of their ion trap mass spectrum is also discussed.
The purity of myrrh batches of various origin were tested according to the DAB 10 (10 th German pharmacopeia) 21 .The contents and structures of the gum fractions were identical despite differences in the essential oil fractions.The raw gums were heterodisperse systems and contained ∼ 70% 4-methyl-glucuronogalactone protein.Therefore, a classification of myrrh in the group of arabinogalactan proteins is no longer correct.
Wang 22 analyzed by capillary GC/MS and GC/FTIR the chemical components of the essential oil of myrrh obtained from Kenya.The oil contained monoterpenes and sesquiterpenes.Researchers identified sixteen main constituents.
The constituents of essential oil in myrrh and gum opopanax were analyzed by GC-MS.Fifteen compounds in Myrrh and 33 compounds in gum opopanax were identified and their percent content was detected.The main constituents of myrrh was furanoeudesma-1,3-diene 14 and the main constituent of gum opopanax was transβ-ocimene 26 (ref. 23).
With the help of Fourier-transform Raman spectroscopy myrrh can be easily distinguished from frankincense and different colored specimens can be identified.Relative proportions of compounds in a sample, and hence the color, is dependent on the climatic and environmental conditions.Myrrh shows more variety in its color (myrrh red, myrrh orange, myrrh yellow, myrrh brown and myrrh black) and in the observed Raman spectra.The common bands which occur for myrrh samples are not specific enough for identification of individual colored myrrh samples 24 .Such non-destructive methods of analysis are preferred by archeologists.
Tree resins have been used extensively throughout history.Tree resins are composed of terpene and terpenoid compounds, and diterpenoids and triterpenoids are the most common.Diterpenoids and triterpenoids have not been found together in a resin; thus, resins from each group have differing properties.Frankincense and myrrh are resins that contain triterpenoid components.Fourier transform-Raman spectrometry has potential as a nondestructive and noninvasive means of identifying both ancient and modern resin samples in situ.Because of that it has advantages particularly in the field of archeological sciences.The spectra of myrrh are very different than those of any of the other resins examined.Myrrh cannot be mistaken for any other resin because it has a high enough proportion of gum to make its spectra unlike those of any of the resins examined by the authors.The spectra of myrrh are easily distinguished from those of the diterpenoid and triterpenoid resins 25 .
The gum myrrh has been used as incense for many centuries.In more recent times, the gum has found medical usage as an antiseptic, the tincture being applied to inflammatory and ulcerated conditions of the throat and mouth.
Extraction with 90% aqueous alcohol the resins are largely removed and the crude polysaccharides are obtained.After hydrolysis at least 15 aminoacids were detected and in fractions D-galactose, L-arabinose, and 4-methyl D-glucuronic acid (in proportions 4 : 1 : 3) were identified 26 .
The eight samples of resin collected in Kenya and attributed to Commiphora myrrha (one of them called C. ellenbeckii) and Commiphora holtziana have been examined.These have yielded a wide range of sesquiterpenes, notably furanosesquiterpenes based on eudesmane, elemane and germacrene (Table 1).The distribution of these compounds is discussed in relation to the collection and commerce of myrrh-like resins in Kenya.The simple sesquiterpenes identified in C. holtziana were comparable to those recorded for opopanax oil 30 .Chemical investigation of Commiphora has been done on some Kenyan species occurring also in Ethiopia.The main volatile components include monoterpenes (limonene 2, p-cymene 45, α-terpineol 46) and sesquiterpenes (β-bisabolene 47)(ref. 35).
Hydrodistillation of the crushed air-dried oleo-gum resin of Commiphora myrrha (Nees) Engl.var.molmol yielded 3.1 % of oil.The chemical composition of the essential oil was examined using GC and GC/MS (Table 3).The relative percentage of the 32 compounds (about 94.6 % of the oil) identified in this oil was calculated from the total ion chromatogram 44 .Myrrh -Commiphora chemistry Most previous reports were based on materials obtained from markets rather than from properly identified trees.Authors here described the results on the volatile oils (obtained by hydrodistillation) of resin collected in Ethiopia from two Commiphora spp.(C.myrrha and C. guidotti).The oils were analysed by GC/MS (Table 4).Using 1 H-and 13 C and GC/MS analysis authors established in their previous work the absence of oxygenated furanosesquiterpenes, curzerenone and furanodienone, and other C-6 oxygenated furanosesquiterpenes in the essential oil as well as extracts of myrrh 45 .The source of adulterant resins coming mainly from C. sphaerocarpa, C. holtziana and C. kataf.
The structures of these compounds were determined on the basis of spectral data, especially of NMR evidence ( 1 H-and 13 C-NMR spectra) and with the help of positive atmospheric pressure chemical ionization mass spectra (APCI MS) and electrospray ionization mass spectra (ESI MS).
Myrrh, a commercially used resin, is mostly from Commiphora molmol, growing wild in Somalia, Jemen and Arabia.It is mainly used in toothpastes and tinctures for treatment of gingivitis.Myrrh is composed of the essential oil (2-10 %), the ethanol soluble resin (25-40 %) and the watersoluble gum (30-60 %).The watersoluble gum fraction of myrrh has been found to comprise of a mixture of proteoglycans (with dominating amounts of uronic acid polymers).After hydrolysis and degradations structural investigations revealed chains of galactose 27, chains of arabinose 28 and 4-O-methyl-glucuronic acid 29 ("4-O-methyl-glucurono-galactan"), arabino-3,6-galactanprotein fractions and protein.Authors studied sugar and amino acid compositions of the fractions and sugar linkages of the fractions.Partial structure of the fractions was proposed.The covalent binding of protein and carbohydrate moiety is most probable.In the crude gum the two aldobiuronic acids 6-O-(4-O-methyl-D-glucuronosyl)-D-galactose 30 and 4-O-(4-O-methyl-D-glucuronosyl)-Dgalactose 31 were identified (ratio 6 : 1)(ref. 50).It is not sure, whether the different proteoglycans represent different polymers resulting from the biosynthesis sequence or whether they derive from a partial degradation during isolation or storage of myrrh.
In antiquity, myrrh was used by the Egyptians for embalming and by the Jews as anointing oil.In St Mark's Gospel, "vinum murratum", wine with myrrh, was offered to Christ before crucifixion.Hexane extract of Commiphora molmol with analgesic activity was separated by silica gel column chromatography and semi-preparative HPLC.From the three identified sesquiterpenes the most abundant compound was furanoeudesma-1,3-diene 14 (> 90 %).The other compounds were isofuranogermacrene 13 and furanodiene 36.The first two compounds were analgesic 51 .

Commiphora opobalsamum
The cardiovascular effects of aqueous extracts from the branches of Commiphora opobalsamum (syn.Commiphora gileadensis (L.) Engl.), tree from the mountains of Ramallah, were investigated.The intravenous administration of 4 mg/kg of the aqueous extract depressed systemic arterial blood pressure by 20 % (P < 0.01) and reduced heart rate of anaesthetised rats by 14 % (P < 0.05).The hypotensive and the bradycardiac effects were immediate and in a dose related manner.The hypotensive effect of C. opobalsamum was inhibited by the pretreatment with atropine sulfate (1-4 mg/kg).These results suggest that the hypotensive effect of C. opobalsamum is due to the activation of muscarinic cholinergic receptors 53 .
Another scientific team re-examined their samples following column and gas chromatographic purification and concluded that oil of opopanax contains α-santalene 84, α-bisabolene 99 and β-bisabolene 47, as well as some other isomeric bisabolene 58 .
With the help of column chromatography of petroleum ether extract of Commiphora mukul a crystalline needles were isolated 66 .An isolated compound (steroid) showed significant anti-inflammatory activity on rat paw edema produced by carrageenin.The activity is dose dependent and much more potent than the resin fraction present in C. mukul.
The compound was found to be three times more potent than the resin fraction isolated from the same drug in inhibiting carrageenin oedema in rats.In the present study was tested efficacy of this compound in a chronic model of inflamation in rats.It looks that this drug is likely to be therapeutically effective as anti-inflammatory or anti-rheumatic drug 67 .
The structures of previously isolated new diterpene hydrocarbon and diterpene alcohol from Commiphora mukul were elucidated and named cembrene-A 122 and mukulol 114 (ref. 71).
Guggulsterol IV 126 and guggulsterol V 127 were isolated from the neutral fraction after saponification of the chloroform extract of guggul gum (Commiphora mukul), and their structures were detected by NMR, mass spectra, and chemical modification 73 .Myrrh -Commiphora chemistry Previously described mukulol 114, a diterpenoid from gum-resin of Commiphora mukul, was studied and its absolute stereochemistry established 74 .
The stereochemistry of guggulsterol-I, a component of the exudate of Commiphora mukul, was established by a single crystal x-ray difraction analysis to be 20(R), 22(R) (ref. 75).With the discovery of the hypolipidemic activity of the gum resin, some chemical investigations have been reported.It was found that guggul resin is a complex mixture of various classes of chemical compounds, such as lignans, lipids, diterpenoids and steroids.From the benzene phase, a waxy solid, which is a mixture of esters based on homologous long chain tetrols and ferrulic acid was identified (144, 145) (ref. 80).
A review with 42 references on the development of gum guggulu, a potent hypolipidemic agent, in India, was published 81 .
Commiphora wightii (Arnott) Bhand produces an oleo gum resin of several medicinal properties.The plant infected with Phoma sp.cause changes in the total chlorophyll (36.65 % decline), soluble sugars (62.77 % reduced) and proteins, phenols (8.1 % increase) and mineral elements (drastic reduction in K + and Na + ) in leaf tissues 82 .
The resins of Commiphora mukul (source of gum guggul in India) and Commiphora incisa (a form of frankincense originating from Somalia and Ethiopia) revealed the anti-inflamatory activity.The resins were extracted by steam distillation.Isolated, previously reported, mansumbinone 146 and mansumbinoic acid 147 showed antiinflammatory effects on oedema and on adjuvant-induced arthritis 83 .
A high-performance liquid chromatographic method has been developed and validated for the profiling and quantitative determination of Z-and E-guggulsterones 117, 118 in Commiphora mukul (guggul) crude resin extracts and final products (tablets, capsules), used today as hypocholesterolemic 85 .
Z-and E-guggulsterone 117, 118 are the main ingredients of an ayurvedic drug "Guggulip", marketed in India as hypolipidaemic drug.The method was developed for simultaneous determination of these stereoisomers in spiked serum 86 .Lowest quantitation limit was 25 ng/ml.This method was applied for the estimation of this two stereoisomers in rat serum after a single oral dose of Zisomer.Repeated analysis showed that the Z→E conversion does not take place in the spiked serum samples, and hence the formation of the E-isomer can be attributed solely due to the in vivo process.
Biotransformation of E-guggulsterone (pregna-4,17( 20 The gum resins of guggul (Balsamodendron or Commiphora mukul Hook.) are prescribed in India as Ayurvedic folk medicines.Guggul is produced by drying the milky-white sap of the tree for one year.From methanolic extract were isolated five new polypodane-type triterpene compounds, myrrhanols A, B, and C, and myrrhanones A and B, together with three known constituents.Myrrhanol A 163 and myrrhanone A 165 were characterized.Myrrhanol A displays a potent anti-inflammatory effect 88 .The structures and absolute configurations of myrrhanol A and myrrhanone A were determined on the basis of chemical and physicochemical evidence 89 .
The conformation of steroid nucleus of guggulsterone E 118, isolated from ethyl acetate extract of Commiphora mukul, was studied 91 .The study did not establish the absolute configuration of this molecule.It has been marked in India as hypolipidaemic drug.
Commiphora wightii is a branched shrub or a small tree found in some states of India and Pakistan.Guggul, the exudates of C. wightii is used in Ayurvedic literature as medicine.Guggul lipid (= a mixture of lipid steroids isolated from the resin) is a potent hypolipidemic agent.It was found that the ethyl acetate extract of C. wightii showed significant in vitro cytotoxicity.After column chromatography two ferrulates were characterized.The absolute configuration of one of the known ferulates (guggultetrol-18 142), was deduced as D-xylo (2S, 3S, 4R-configuration).The alcohols obtained by hydrolysis of the ferulates were concluded to be a mixture of (Z)-5tricosene-1,2,3,4-tetraol 175 and (Z)-5-tetracosene-1,2,3,4tetraol 176 (ref. 92).This new class of naturally occurring lipids showed strong cytotoxic activity and some free radical scavenging activity.
Three new and five known compounds were isolated from the oleogum resin of Commiphora wightii (Arnott.)Bhand.[syn.= Commiphora mukul (Hook ex Stocks) Engl.], which is endemic to the Indian peninsula and grows wild in India and Pakistan.This exudates possess a variety of pharmacological activities.Five previously isolated compounds were Z-guggulsterone 117, E-guggulsterone 118, guggulsterol-I 119, myrrhanol A 163 and myrrhanone A 165. Another three compounds, Guggulsterone-M 177, dehydroguggulsterone-M 178 and guggulsterol-Y 179, were new 93 .
An ethanolic extract of air-dried trunk of Commiphora wightii (Arn.)Bhandari (= C. mukul Hoox ex Stocks) was separated on column packed with silica gel to give a new antifungal flavone named muscanone 180 and already known naringenin 181 (ref. 94).Muscanone was active agains Candida albicans in microbial sensitive assay.
Four active compounds, mansumbinone 146, mansumbinoic acid 147, picropolygamain 200 and lignan-1 (methoxy-1,2,3,4-tetrahydropolygamain) have been purified from anti-inflammatory extracts of Commiphora kua 98 .These molecules inhibit the formation of myeloperoxidase products.Myrrh -Commiphora chemistry Commiphora kua (J.F. Royle) Voleesen var.gowlello (Sprague) J. B. Gillett, a 3-5 m tall tree is found mainly in Kenya, Somalia, Ethiopia and Arabia.It produces wood that is used to make household utensils, furniture and tools.During rainy season, its trunk is cut and sucked to quench thirst.In dry season, the tree produces a brown resin, which is used as incense.
Ground resin from this tree was extracted with petrol.TLC analysis of this extract indicated the presence of at least six compounds.With the help of column chromatography over silica gel four already known compound -mansumbinone 146, mansumbinol 201, (16S, 20R)-dihydroxydammar-24-en-3-one 202 and T-cadinol 70 -and two new octanordammarane triterpenes, 15α-hydroxymansumbinone 203 and 28-acetoxy-15α-hydroxymansumbinone 204, were isolated and identified.Structures of these two compounds were elucidated by spectroscopic techniques (MS, IR, UV, 1 H-and 13 C-NMR, X-ray analysis) 99 .
The genus Commiphora Jacq.(= Balsamodendron Kunth), natural order Burseraceae, has not been extensively studied before.Myrrh is usually obtained from C. abyssinica (Berg) Engl., C. molmol Engl.and C. opobalsamum (L.).It has been found to consist of volatile oils, mostly mono-and sesquiterpenes.The presence of triterpenes has never been suggested.
C. pyracanthoides Engl.(= C. glandulosa Schinz), a tree growing in the arid parts of Southern Africa, is rich source of triterpene acids, both free and combined as glycosides.Five free acids (comic acid A 212, B 213, C 214, D 215, and E 216) were isolated from the ethereal solution of the resin 101 .In contrast, the resin from C. mukul is completey devoid of triterpenoids.
It is concluded that the botanical origin of scented myrrh -"bissa bol" (Hindi) or "hebbakhade" (Somali) -a major article for export from Somalia since ancient times, is Commiphora guidottii (Burseracae) and not C. erythraea as generally has been presumed.The reasons for the previous confusion were discussed and an updated synonymy and distribution map for C. guidottii was given 107 .
The mass spectra of previously isolated methyl commates A to E 212-216 from Commiphora pyracanthoides were illustrated 108 .
The gum of Bdellium that was studied was African in origin, produced by Commiphora africana.The Galbanum gum probably came from Ferula galbaniflua.The former gum was more resistant to hydrolysis than the latter, contained more protein, and consumed more periodate during oxidation.In both instances galactose 27 and arabinose 28 were resistant to oxidation, suggesting that these sugars were involved in 1→3 linkages or branching at position 3.The amount of HCOOH produced was higher in the case of Bdellium gum, and suggested the oxidation of terminal molecules and branching.The uronic acids were galacturonic 220 and 4-methyl-glucuronic 224, the latter predominating 111 .
The essential oils obtained from the leaves of Commiphora africana and Xylopia aethiopica from Benin were analyzed by GC, GC/MS and 13 C-NMR.Leaf essential oil of C. africana contained fairly high amounts of sesquiterpenes, among which α-oxobisabolene 225 was the most important (61.6 %).X. aethiopica was characterized by a high content of β-pinene 196 (34.9 %), elemol 42 (14.9%) and α-pinene 1 (11.6 %) 112 .The leaf essential oil of X. aethiopica contained mainly sesquiterpenoid compounds which amount to about 36.6 %.
The methanolic extract of bark of the plant Commiphora africana gave a homogenous product through chromatographic separation which after crystallization from methanol furnished needles characterized as dimethylterephthalene (benzene-1-dicarboxylic acid dimethylester) 229 on the basis of spectral analysis 114 .Myrrh -Commiphora chemistry A heavily spined shrub or small tree found in Kenya, Commiphora incisa Chiov.(syn.C. candidula Sprague), exudes after injury a liguid, which quickly hardens and formed resin becomes with age crystalline.An ether extract of this resin was prepared.On chromatographic column packed with silica two aryltetralin lignans were isolated.The first lignan appeared to be the known lignan polygamain 230 [Hokanson G.C.: J. Nat.Prod.42, 378  (1979)] previously reported from Polygala polygama Walt.The second one, an isomer of the first one, was identified as picropolygamain 200 (ref. 115).
The major alkanone constituents of the resin of Commiphora rostrata, 2-decanone and 2-undecanone, and a series of structural analogues were bioassayed for their repellency against the maize weevil, Sitophilus zeamais in olfactometric assays 119 .All the aliphatic ketones and aldehydes showed comparable or greater activity than the synthetic commercial insect repellent N,N-diethyl toluamide (DEET).In the 2-alkanone series the C-8 and C-9 compounds demonstrated significantly higher activity than their shorter-and longer-chained congeners.Analogues differing in the relative positions of the carbonyl group, including aldehydes, showed a variable pattern of repellency.Alkanols appeared to be mildly attractive to the weevil.The results supported author's previous suggestion that the resin constituents may play an allomonal role in the ecosystem where the plant thrives.
Extraction of the stem bark of Commiphora dalzielli Hutch.(a shrub or small tree indigenous to Ghana) with petroleum gave seven dammarane triterpenes.The two compounds were identified as common lupeol 234 and β-amyrin 211.Five of them were separated by column chromatography with silica gel and circular preparative thin-layer chromatography.After purification epilupeol 235, cabraleadiol 3-acetate 236, cabraleone 237, cabraleadiol 238 and isofouquierone 239 (ref. 121).Both the acetate and isofouquierone appear to be new compounds.
In the essential oil of Commiphora quadricincta a large number of the compounds were identified by GC-MS and the following compounds with retention times of authentic samples (Table 6).A significant number of the compounds identified were terpenoids.Volatiles collected before the rains were comparatively richer, particularly in the more volatile fractions 122 .An exudate from Commiphora tenuis was collected in Ethiopia.After removal of the gum from the gum-resin and column chromatography four free triterpenes.The main triterpene was characterized as 3β-O-acetoxyolean-12-en-28-oic acid 256 (ref. 123).After steam distillation the oil was taken up in n-pentane and analyzed by GC and GC-MS.Composition of the essential oil in the oleo-resin was as follows (37 compounds were identified -Table 7).
Very little is known about the chemistry of resins derived from others than usually studied Commiphora species, of which there are more than 50 in Ethiopia 125 .
Commiphora erlangeriana, occurring in Ethiopia and Somalia is known as "dhunkal"."Dhunkal" resin is toxic to humans and animals.However, the fruits are edible and sold in markets during rainy seasons.The powder resin was extracted with a mixture of methanol -ethyl acetate.After column chromatography four new lignans were identified in extract, two of the polygamain-type, named erlangerin A 273 (the most abundant compound -41 %) and erlangerin B 274, and two related to podophyllotoxin, named erlangerin C 275 and erlangerin D 276 (ref. 126).
As the resin of Commiphora erlangeriana is known to be poisonous to humans and animals and has traditionally been used as an arrow poison, the recently found four erlangerins (A to D) were studied for their toxicity to mammalian cells.Two human (HeLa and EAhy926) and two murine (L929 and RAW 264.7) cell lines were used for toxicity assays.As assessed by the MTT assay, the effects of erlangerin C and D closely follow the activity profile of podophyllotoxin: they induced a concentration-dependent cytotoxicity in the murine macrophage cells (RAW 264.7) and a cytostatic effect in HeLa, EAhy926 and L929 cells.In contrast, erlangerins A and B suppressed cell viability at relatively higher concentrations (EC 50 values higher than 3µM as compared with nM concentration range for erlangerins C and D and podophyllotoxin) and their ac-tivity appears to be consistent with a cytotoxic mode of action in all cell lines studied 127 .
Volatile oils obtained by the steam distillation of aromatic resin with attractive odour from Boswellia neglecta, Commiphora africana, Commiphora campestris and Commiphora ogadensis have been examined by capillary GC and GC/MS.In each case the volatile oils appeared entirely monoterpenoid in constitution (Table 8).All four oils were generally characterized by high concentration of α-pinene 1.Other constituents that were important mark- Bioassay-guided fractionation of a crude extract from Commiphora africana led to the isolation of the dihydroflavonol glucoside phellamurin 279 (ref. 130).
Color and precipitation reactions proved the presence of condensed tannins and these were detected for the powdered bark and alcoholic extract of Commiphora angolensis, respectively.An unsuccessful attempt was made by using ascending paper chromatography to identify the phenolic compounds present.By elution of a fraction separated on a thick paper chromatogram with HCl-MeOH, ascending paper chromatography separated petunidin 3-rhamnoglucoside 288 (buthanol -acetic acid -water, BuOH -HCl and 1% HCl) 135 .

Fig. 1 :
Fig. 1: A computer generated perspective drawing of guggulsterol-I.Hydrogens are omitted for clarity.Adopted by authors.

Table 4 .
The composition of Ethiopian Commiphora essential oils.
L. O. Hanuš, T. Řezanka, V. M. Dembitsky, A. Moussaieff . The allylcembrol structure was established by mild dehydration which yielded cembrene and by spectral analysis.Allylcembrol and its C2 epimer were synthetized from isocembrol.Guggulu (Sanskrit) is the gum resin exudates from the tree Commiphora mukul (Hook, ex Stocks) Engl.and is article of commerce in India.Chromatography of pe-

Table 5 .
Relative concentrations (%) of volatile components of the leaf oil of Commiphora africana (A.Rich.)Engl.from Benin.

Table 6 .
Compounds identified in the essential oil of C. quadricincta (evidence by MS and retention time).

Table 7 .
Composition of the essential oil in the oleo-resin of Commiphora tenuis.

Table 8 .
Concentration (%) ranges of 12 monoterpenes in the volatile portion of the resins.
* Present in two West African samples from Bourkina Faso

Table 9 .
Relative concentrations (%) of volatile components of the resins.The structure of the novel compound was determined as 1,2-epoxyfurano-10(