The genus Croton belongs to the family Euphorbiaceae and a great number of species are used in popular medicine for the healing of wounds and ulcers (1). Here, we describe the isolation of the alkaloids of Croton celtidifolius Baill., a tree of moderate size growing in the mountains of Teresópolis (state of Rio de Janeiro). The leaves and twigs (872 g) of C. celtidifolius were extracted with ethanol and the dried extract was fractionated between 5 % aqueous HCl and CHCl3. The aqueous acidic layer was adjusted to pH 10 with NH4OH (conc.) and extracted with CHCl3. The alkaloidal mixture (210 mg) was chromatographed on a column of silica gel using successively CH2Cl2: EtOAc (1:1), EtOAc, and EtOAc: MeOH (1:1), yielding isoboldine [114 mg, recrystallisation from EtOH, m.p. 127—129°C, [α]D: +67° (c 0.1, MeOH)], reticuline [20.7 mg, [α]D: —107° (c 0.1, MeOH)], and a mixture of two alkaloids, isoboldine (28 mg) and laudanidine [16 mg, [α]D: +139° (c 0.1, MeOH), m.p. 177—179°C], which were separated by preparative TLC on silica gel with CHCl3: EtOAc: MeOH (2 : 2 : 1). The alkaloids were identified by comparison with data already reported (2—4) ([α]D, IR, 1H- and 13C-NMR, MS) and HOMOCOSY 1H × 1H data. None of the three alkaloids described have been previously isolated from plants of the genus Croton. Isoboldine has been found in various genera of Lauraceae, Papaveraceae, and Annonaceae (5). Reticuline and laudanidine have been isolated respectively from Desmos tiebaghiensis (3) and Cryptocarya amygdalina (4). A voucher specimen (No. 185344) has been deposited in the herbarium of the Federal University of Rio de Janeiro. Information in detail on the work-up procedure and copies of the original spectra can be obtained from the author on request. Viburnum lantana L var. discolor Huter (Caprifoliaceae) is a deciduous shrub, endemic of South Yugoslavia, which was considered in the past as a distinct species, named V. maculatum Pantocsek (1, 2). The plant material (150 g of stem bark) was collected on the mountain of Lovcen, near Cetinje (Montenegro). A voucher specimen was deposited at Dipartimento di Biologia Vegetale, Università "La Sapienza", Rome, Italy [RO general herbarium]. Viburnum species are known for their spasmolytic and uterusrelaxant properties (3, 4). In the last years, several Valeriana-type iridoid glycosides (characterized by a β-o-glucopyranosyl moiety bound to C-1 and an esterifying isovaleroyl group at C-1) have been isolated from Viburnum spp. (5—7). The present study on V. lantana var. discolor reports the isolation of three Valeriana-type iridoid glucosides. On the basis of comparison with published spectroscopic data, compounds 1 and 2 proved to be 2'-acetyldihydropenstemide ([α]D: —66.6°, c 0.3, MeOH) and 2'-acetylpatrinoside ([α]D: — 54.5°, c 2.0, MeOH), two iridoid glucosides already isolated from Viburnum lantana L (8). The 1H-NMR data of compound 3 also revealed the base structure of patrinoside (9), with small differences due to the acetylation of an oxymethine belonging to the glucose moiety (triplet at δ= 4.84). Owing to a partial superposition of the glucose signals with the CHD2OD peak, the unambiguous assignment of the acetylation site was obtained by registering a new proton spectrum of 3 in D2O. These additional data, confirmed by further NMR experiments, including 1H, 13C, 1H-1H COSY and 1H-13C HETCOR, allowed us to assign to 3 the structure of 3'-acetylpatrinoside. The MeOH extract of the plant stem bark, worked up as previously described (10), gave an EtOAc-soluble fraction, which, subjected to CC on silica gel with MeOH-CHCl3 (1:9), afforded pure 1 (12 mg), 2 (50 mg), and 3 (10 mg).