Bioactive properties of solvent extracts of  Tasmannia lanceolata ,  Backhousia citriodora  and  Syzygium anisatum  investigated. The antimicrobial activities evaluated using agar disc diffusion method against two bacteria ( Escherichia coli  and  Staphylococcus aureus ) and six weak-acid resistant yeasts ( Candida albicans ,  Candida krusei ,  Dekkera anomala ,  Rhodotorula mucilaginosa ,  Saccharomyces cerevisiae  and  Schizosaccharomyces pombe ). The antioxidant activities determined using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging and reducing power assays. Quantification of major active compounds using ultra-high performance liquid chromatography. Extracts showed broad-spectrum antifungal activity against weak-acid resistant yeasts in comparison to the standard antifungal agents, fluconazole and amphotericin B.  Dekkera anomala  being the most sensitive and strongly inhibited by all extracts, while  Escherichia coli  the least sensitive. Polygodial, citral and anethole are the major bioactive compounds identified in  Tasmannia lanceolata ,  Backhousia citriodora  and  Syzygium anisatum , respectively. Hexane extracts contain the highest amount of bioactive compounds and demonstrate the strongest antimicrobial activities. Methanol and ethanol extracts reveal the highest phenolic content and antioxidant properties. Fluorescence microscopic results indicate the mechanism of action of  Backhousia citriodora  against yeast is due to damage of the yeast cell membrane through penetration causing swelling and lysis leading to cell death.