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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