1.  Murraya, together with the closely allied genera Clausena and Glycosmis

makes up the subtribe Clauseninae of the tribe Clauseneae in the rutaceous subfamily

Aurantioideae.  The center of distribution of the genus Murraya lies in southern China

and Indo-Malaysia, with a few small endemic species or varieties stretching to Sri Lanka and to New Caledonia and northeastern Australia.  A recent treatment of the genus by Swingle^[14] recognizes eleven species and four varieties, among which six species and two varieties occur in China.  Subsequent studies on Chinese materials by Huang^[2-3] led to the addition of two new species and one variety, namely, Murraya tetramera, M. Kwangsiensis, and M. kwangsiensis var. macrophylla; the former species, M. tetramera, has since been found to be identical with M. euchrestifolia^[4-5]. Huang also reinstated M. exotica as a species distinct from M. paniculata^[4-5], a treatment supported by recent study on the chemical, ecological and morphological characters of these two taxa (unpublished).

Moreover, two of the varieties recognised by Swingle, namely, M. paniculata var. omphalocarpa and M. alata var. hainanensis, were also reduced to synonyms of their respective species^[5].  Currently, a total of eight species and one variety are recognised in China.

     Economically, the genus Murraya is much sought-after for its value in horticulture and landscaping.  The fresh leaf of M. koenigii is a constant and essential component in preparing curry.  Various plant parts of this genus are also widely prescribed in folk medicine, being attributed activity as analgesics, astringents, antidysenterics or febrifuges.  The root and stem of M. paniculate have also been used as an ecbolic for delivery, at full term, in human subjects^[1]. Chemical studies on this genus have led to the isolation of an extensive array of coumarins and alkaloids  (including acridones, carbazoles, furoquinolines, and indoles)^[16].  Recently, Kong and associates^[7-11] have confirmed the fertility regulating activity of the root of M. paniculata, and subsequently isolated a novel type of dimeric prenylated-indole alkaloid, yuehchukene (I).  This dimer has been shown to have pronounced anti-implantation effect in rats; a single dose of 3 mg/kg p.o. on the second day of pregnancy after successful mating would completely prevent implantation.  However, the yield of yuehchukene obtained from M. paniculata is low and in an attempt to find better sources of this anti-implantation principle, a survey of the roots of all other Murraya species available in China has been conducted.  Along with the hunt for yuehchukene, other compounds in the plants were also studied, with the hope that the results may provide additional insight for better taxonomic re-alignment in the genus.

     2.  Yuebchukene was found in the root samples of three species, namely, M. alata,

M. exotica and M. paniculata (in cluding two samples of M. paniculata var. omphalocar-

pa from Taiwan).  From the same sources of materials, a number of 8-prenylated cou-

marius, but no carbazole, were also isolated. Four of the remaining species, viz. M. cre-

nulata, M. cuchrestifolia, M. koenigii and M. microphylla, were found to contain the car-

bazole girinimbine; murrayafoline-A was also isolated from M. crenulata and M. euchre-

stifolia. The last species, M. kwangsiensis, was found to contain an unidentified carba-

zole.  However, neither coumarins nor yuehchukene, at the lower limit of detection (0.1

mg/100 g), were found in these five species. The distribution of these major groups of

chemical constituents is summarised in Table 1.

     3.  The two groups of species also differ from each other by a combination of se-

veral morphological characters.  Plants of the first group, which contain yuehchukene

and 8-prenylated coumarins but no carbazole, have straw to light greyish yellow stems

and root bark, larger petals (1-2cm long), and red, ellipsoid fruits.  On the other

hand, plants of the second group, characterized by the presence of carbazoles and the

absence of yuehchukene and 8-prenylated coumarin, have dark brown stems and root

bark, smaller petals (4-7 mm long), and purplish black and globular to ellipsoid fru-

its.

      4.  In a recent treatment of the genus, Swingle^[14] indicates that the species he re-

cognised fall into 2 or 3 groups, not as yet adequately studied.  However, he did not ex-

pand further on this obervation and shed light on where to delimit the groups he allu-

ded to.  Our results demonstrate that the eight species of Murraya in China can be di-

vided into two groups, which differ from each other in both external morphology and

chemical constituents.  Accordingly, to reflect the relationship among the eight species

found in China, we find it appropriate to divide the genus into two sections. This idea

was also conceived by Tanaka^[15], based solely on morphology of the plants, and presen-

ted in an older monograph of the genus (under the generic name Chalcas) published in

an obscure journal issued in Taiwan during Japanese occupation. Tanaka's paper was

made available to us after we had completed our analysis and drawn up our taxonomic

interpretation.  Tanaka's classification basically matches the sections we intended to

propose.