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Four phloroglucinol derivatives (kamalins) have been isolated from Mallotus philippinensis. These are rottlerin (la), isoallorottlerin (II), the ,,red compound" (III) and the ,,yellow compoundc' (IV). In addition. methylene-bis-rnethylphloroacetophenone (V) has been detected by TLC. The natural occurence of these substances is discussed. Rksumk Quatre de'rivks phloroglucinoliques (kamalines) ont e'tk isolks de Mallotus philippinensis. Ils sont la rottlkrine (la), Pisoallorottle'rine (II), la ,,substance rougeP (Ill), et la ,,substance jaune" (IV). De plus, le mkthylkne-bis-me'thylphloroacktophknone (V) a ktk dktectk par la CCM. L'existence naturelle des ces substances est discutke. Mallotus philippinensis (LAM.) M~~LL.-ARG. (Euphorbiaceae)' is a dioecious shrub or small tree indigenous to southeastern Asia and widely distributed throughout tropical Asia, Australia and the Philippines [I]. The drug, Kamala, a red powder consisting of glandular and stellate non-glandular hairs from the cHpsules of the plant, has long been used as an anthelminticum and as an orange dye for silk. Kamala has been included in several European pharmacopoeias. According to early chemical investigations [I], kamala contains phenolic compounds of which rottlerin (mallotoxin) is the main compound. It was first isolated in 1855 by ANDERSON [l]. AS a result of extensive studies by British [3-71, Indian [8-91, and German [10-111 investigators before World War I1 the structure (Ia) was accepted for rottlerin [ 6 ]. NARANG et al. [8-91 also isolated in 1937.a The genus Mallotus LOUR. consists of 140 species distributed in eastern and southeastern Asia, Indomalesia, New Caledonia, Fiji and northern and eastern Australia. Two taxa also occur in tropical Africa and Madagascar [2].

Dried leaves of Catharanthus roseus were extracted with aqueous acidic 0.1 M solution of HCl. Alkaloid-embonate complexes were obtained as precipitates by treating the extract with an alkaline (NaOH) solution of embonic acid (4,4'-methylene-bis-3-hydroxynaphtalenecarboxylic acid). The precipitate mainly consisted of catharanthine and vindoline embonates and it was directly used as the starting material for a semisynthesis of the anti-cancer bisindole alkaloid vinblastine. The coupling reaction involved oxidation of catharanthine in aqueous acidic medium by singlet oxygen ( 1 O 2 ), continuously produced in situ by the reaction between H 2 O 2 with NaClO. An excess of NaBH 4 was used for the reduction step. Analysis of the reaction mixture indicated a maximum yield of 20% for vinblastine at pH 8.3, based on the initial amount of catharanthine concentration. Direct-injection electrospray ionization mass spectrometry in positive ion mode was used for the identification of vinblastine. The mass spectra of

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Effects of various β‐carbolines (BC's) and two tetrahydroisoquinolines (TIQ's) on the specific binding of a natural opiate δ‐receptor ligand, leucine enkephalin, have been studied in rat synaptosomal membranes, and compared with the effects on the binding of mu‐receptor ligands dihydromorphine and naloxone. Harmaline (7‐MeO‐1‐Me‐dihydro‐BC) was the most potent compound studied (Ki value 3.5 μM), while the two TIQ's (salsolinol and salsolidine) were less potent than BC's (Ki> 100 μM) in inhibiting the binding of δ‐receptors. In general, BC's showed more affinity for δ‐receptors than for μ‐receptors; salsolinol was more potent against the binding of μ‐receptors. Inhibition of binding was generally of the competitive type: Kd values increased and Bmax values were not altered. The Na dependence suggests that BC's and salsolinol are antagonists or partial agonists of opioids. Since the binding affinity of BC's and TIQ's was on the micromolar level only, the opiate receptors do not appear to be the major sites of action for BC's or TIQ's.

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