Triterpene saponins from Randia formosa.

Seven new triterpenoid saponins, randiasaponins I (1), II (2), III (3), IV (4), V (5), VI (6) and VII (7) as well as two known ones, ilexoside XXVII (8) and ilexoside XXXVII (9), were isolated from the methanolic extract of the leaves of Randia formosa. The structures of the new saponins were established as 3-O-alpha-L-arabinopyranosyl-3 beta,19 alpha,23-trihydroxyursa-12,20(30)-dien-28-oic acid 28-beta-D-glucopyranosyl ester (I), 3-O-beta-D-glucopyranosyl-(1 --> 3)-alpha-L-arabinopyranosyl rotundic acid (2), 3-O-beta-D-glucopyranosyl-(1 --> 3)-alpha-L-arabinopyranosyl pomolic acid 28-beta-D-glucopyranosyl ester (3), 3-O-51-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranosyl pomolic acid 28-beta-D-glucopyranosyl ester (4), 3-O-a-L-rhamnopyranosyl-(l --> 2)-alpha-L-arabinopyranosyl siaresinolic acid 28-beta-D-glucopyranosyl ester (5), 3-O-alpha-L-arabinopyranosyl ilexosapogenin A 28-beta-D-glucopyranosyl ester (6), and 3-O-beta-D-glucopyranosyl ilexosapogenin A 28-beta-D-glucopyranosyl ester (7), based on spectral and chemical evidence. Besides the saponins, two common flavonoids kaempferol 3-O-rutinoside and rutin were also isolated. (C) 2000 Published by Elsevier Science Ltd. All rights reserved

Isoquinoline alkaloids from Artabotrys brachypetalus

The genus Artabotrys contains more than 100 species throughout tropical Africa and East Asia. A. brachypetalus Benth. (Annonaceae) is a small tree, shrub or liane, described firstly as a plant located only in Zimbabwe but also known to occur in Zambia (Baker, 1911). Material was collected near Bulawayo (Zimbabwe) in February 1996 and identified by S. Mavi. A voucher specimen (2724.000) has been deposited in the National Herbarium of Zimbabwe (SRGH) in Harare

Isolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare

The isolation and identification of major phenylpropanoid esters from Marrubium vulgare: (+) (E)-caffeoyl-L-malic acid 1, acteoside 2, forsythoside B 3, arenarioside 4, ballotetroside 5, as well as their anti-inflammatory activity are reported for the first time, We evaluated the inhibitory effects of these five compounds on cyclooxygenase (Cox) catalysed prostaglandin biosynthesis activity. Only the glycosidic phenylpropanoid esters showed an inhibitory activity towards the Cox-2 enzyme and three of them: acteoside 2, forsythoside B 3, arenarioside 4, exhibited higher inhibitory potencies on Cox-2 than on Cox-1. These results are of interest, as Cox-2 is mainly associated with inflammation and the Cox-1 inhibition with adverse side effects often observed with non-steroidal anti-inflammatory drugs. The occurence of these phenylpropanoid esters could also explain some other pharmacological properties of M. vulgare. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved

Antimicrobial and acetylcholinesterase inhibition activities of an endemic plant from Sahara: Myrtus nivellei Batt. & Trab. (Myrtaceae)

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