Some botanical species with a large use in folk medicine of Rwanda (1) have been screened for their antimicrobial (2,3), antifungal, and antiviral activities (4). Lantana trqolia L. (Verbenaceae) has been included in this study and has been selected for a more detailed investigation of its active principles. The genus Lantana is known to contain various terpenoid compounds (Lantana camara and Lantana tiliaefilia) (5- IO), flavonoids and naphthoquinones (Lantana archiranthifolia (1 I), and cinnamylglycoside derivatives (Lantana hybrzda) ( 12,13). TO our knowledge no previous chemical or biological studies of L. trifolia have been reported.We have isolated from the MeOH extract of the dried leaves a new, antimicrobially active, polymethoxylated flavone and have named it umuhengerin after the Rwandese name of the plant. The structure of the compound has been established as 5-hydroxy-6,7,3',4', 5 Ipentamethoxyilavone El]. This substance has earlier been found to be present as a minor constituent in a sample of 5-hydroxy-6,7,3 ' ,4'-tetramethoxyflavone but was never isolated from theOMe mixture (14). It was tentatively identified by comparison of the ms and 'Hnmr impurity peaks obtained for the mixture (15).Umuhengerin exhibited in vitro antibacterial and antifungal properties in concentrations up to 200 pg/ml against various pathogens including Staphylococcus aureus, Salmonella typhimurium, Candida tropicalis, Aspergillus niger, Aspergillus fumigatus, Trichopyton mentagrophytes, and Microsporum canis. It showed no antiviral activity in the concentrations tested. The results of the chemotherapeutic testing are presented in Table 1.