activity of a methanol extract and isolated constituents of Mitracarpus scaber, a species used in folk medicine by West African native people, was evaluated against Staphylococcus aureus and Candida albicans strains. The mitracarpus methanol extract possesses both antibacterial and antimycotic activities (minimum inhibitory concentration-MIC 31·25 and 62·50 mg ml −1 , respectively). This extract was subsequently fractioned and monitored by bioassays leading to the isolation of seven compounds screened for antibacterial and antimycotic activities. Among these compounds, gallic acid and 3,4,5-trimethoxybenzoic acid inhibited the growth of Staph. aureus (MIC 3·90 and 0·97 mg ml −1 ). 4-Methoxyacetophenone and 3,4,5-trimethoxyacetophenone effectively inhibited C. albicans (MIC 1·95 mg ml −1 ). The other compounds (kaempferol-3-O-rutinoside, rutin and psoralen) which were also isolated showed low antibacterial and antimycotic activities (125-500 mg ml −1 ).

Aims: Three conventional methods and a multiplex PCR procedure with a set of four primers (Quadruplex‐PCR) were used to differentiate between aflatoxin‐producing and non‐producing strains of the Aspergillus flavus group. Methods and Results: By combining sets of primers for aflR, nor‐1, ver‐1 and omt‐A genes of the aflatoxin biosynthetic pathway, Quadruplex‐PCR showed that aflatoxinogenic strains gave a quadruplet pattern, indicating the presence of all the genes involved in the aflatoxin biosynthetic pathway which encode for functional products. Non‐aflatoxinogenic strains gave varying results with one, two, three or four banding patterns. A banding pattern in three non‐aflatoxinogenic strains resulted in non‐differentiation between these and aflatoxinogenic strains. Conclusion and Significance and Impact of the Study: Because conventional methods are time‐consuming, further studies are needed to develop a rapid and objective technique that permits complete differentiation between aflatoxin‐producing and non‐producing strains of the A. flavus group.

In the present paper we report the 'in vitro' activity of eight aliphatic long-chain aldehydes from olive flavor (hexanal, nonanal, (E)-2-hexenal, (E)-2-eptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal and (E,E)-2,4-decadienal) against a number of standard and freshly isolated bacterial strains that may be causal agents of human intestinal and respiratory tract infections. The saturated aldehydes characterized in the present study do not exhibit significant antibacterial activity, while the alpha,beta-unsaturated aldehydes have a broad antimicrobial spectrum and show similar activity against Gram-positive and Gram-negative microorganisms. The effectiveness of the aldehydes under investigation seems to depend not only on the presence of the alpha,beta-double bond, but also on the chain length from the enal group and on the microorganism tested.

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