In the course of our current screening project on biologically active substances of S. and S.-E. Asian Rutaceae, we isolated two antifungal compounds from the lipophilic leaf extract of Glycosmis cyanocarpa (Blume) Spreng. collected in Sri Lanka. They were detected by bioassay-guided TLC analyses on crude extracts using a spore suspension of the phytopathogenic fungus Cladosporium cladosporioides. Their structures were determined by means of spectroscopic methods as the new sulfur-containing cinnamides sinharine and methylsinharine (1). Biogenetically, the sulfur-containing amine part may be derived from cysteine by decarboxylation and methylation. From a corresponding leaf extract of the Malayan G. chlorosperma Spr., collected in the rain forest of Penang island, we obtained another pair of isomeric sulfur-containing amides designated as penangin and isopenangin (2). Here again, cysteine may be assumed to be the sulfur-donating moiety. However, in contrast to the sinharines, it represents the acid part which most likely has been formed by deamination and methylation. Both sinharines and penangins represent a novel type of amides which appear to be restricted to the genus Glycosmis. In the case of penangins no antifungal activity has been observed against Cladosporium. HPLC analyses linked with on-line UV-photodiode array detection of the crude extracts from the leaves, stems, and roots have shown that the accumulation of amides is restricted to the leaves. Moreover, a preliminary comparison of the various HPLC profiles obtained from other Glycosmis species and provenances is indicative of a more widespread distribution of penangins. Generally, the chemical make-up of Glycosmis, as clarified by HPLC, will provide an excellent systematic criterion for a more natural infrageneric classification which is at present in a chaotic condition.