Background. Candidiasis is the common name for diseases caused by yeast of the genus Candida. Candida albicans is one of the most implicated species in superficial and invasive candidiasis. Antifungals, polyenes, and azoles have been used to treat candidiasis. However, due to the development of antifungal resistance, research of natural substances with potential antifungal effects at low concentrations or combined is also a possibility. Methods. The broth microdilution method was used to evaluate the antifungal activity. The biofilm formation was assessed using the microtiter plate method. The antibiofilm activities were assessed using micro plaque tetrazolium salt assay (MTT). The combination effect of antifungal with natural substances was made using the checkerboard method. Results. Among our isolates, clotrimazole was the most resistant, but amphotericin B was the most effective antifungal. The biofilm was formed by all isolates of C. albicans. Curcumin and piperine displayed antibiofilm activity with minimum biofilm inhibitory concentration (MBIC) and minimum eradicating concentration (MBEC) ranging from 64 to 1024 μg/mL and 256 to 2048 μg/mL. In combination, piperine presented double synergistic effects compared to curcumin with all antifungals tested. Curcumin shows more synergistic effect when combined with polyenes than with azoles. However, piperine shows a more synergistic effect when combined with azoles compared to polyenes. Conclusion. C. albicans was susceptible to curcumin and piperine both on planktonic cells and biofilm. The combination of curcumin and piperine with antifungals has shown synergistic effects against multiresistant clinical isolates of Candida albicans representing an alternative drug research for the treatment of clinical candidiasis.

Medicinal plants are rich sources of bioactive compounds with diverse pharmacological properties, including antimicrobial activities. This study aimed to assess the antibiofilm potential of methanol and ethanol extracts from nine selected medicinal plants, as well as their synergistic effects with doxycycline against Bacillus strains. Standard procedures were employed to determine the phytochemical composition, total phenolic, and flavonoid contents of the extracts. The antibacterial activity was evaluated using the broth microdilution method, while biofilm formation was assessed via the microtiter plate method. Antibiofilm activity was determined using the 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium‐bromide (MTT) assay. Combination studies were conducted using the checkerboard microdilution method. All extracts contained phenols, flavonoids, steroids, triterpenes, and anthraquinones. The methanolic extract of Psidium guajava exhibited the highest total phenolic and flavonoid contents (90.48 ± 0.55 mg GAE/g), while the ethanolic extract of Olax subscorpioidea showed the highest flavonoid content (6.48 ± 0.33 mg QE/g). Ethanol extracts of Eucalyptus globulus and Psidium guajava and methanolic extract of Syzygium jambos demonstrated significant antibacterial activity against Bacillus anthracis 34F2 Sterne strains, with a MIC value of 64 μg/mL. Biofilm formation in Bacillus strains was notably enhanced in the presence of glucose. The methanolic extract of O. subscorpioides exhibited the highest biofilm imbibition (85%), while Picralima nitida methanolic extract showed the most effective biofilm eradication (79%). The combination of Solanum torvum ethanol extract with doxycycline displayed synergistic effects against biofilm formation inhibition and eradication in all tested Bacillus strains. Taken together, Solanum torvum ethanol extract shows promise for developing new combination antibacterial therapies.

Four previously unreported triterpenoid saponins named 3β-hydroxy-23-oxours-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester (mannioside G) (1), 23-O-acetyl-3β-hydroxyurs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester (mannioside H) (2), ursolic acid 28-O-[α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl] ester (mannioside I) (3), and 3β-hydroxy-23-oxolup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl ester (mannioside J) (4) were isolated as minor constituents from the EtOAc soluble fraction of the MeOH extract of the leaves of Schefflera mannii along with the known compounds 23-hydroxyursolic acid 28-O-β-D-glucopyranosyl ester (5), ursolic acid 28-O-β-D-glucopyranosyl ester (6), pulsatimmoside B (7) betulinic acid 28-O-[α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl] ester (8), 23-hydroxy-3-oxo-urs-12-en-28-oic acid (9), hederagenin (10), ursolic acid (11), betulinic acid (12), and lupeol (13). Their structures were elucidated by a combination of 1D and 2D NMR analysis and mass spectrometry. The MeOH extract, the EtOAc and n-BuOH fractions, and some of the isolated compounds were evaluated for their antibacterial activity against four bacteria: Staphylococcus aureus ATCC1026, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC10536, and Klepsiella pnemoniae ATCC13882. They were also screened for their antioxidant properties, but no significant results were obtained.

Urinary tract infections (UTIs) are one of the most important causes of morbidity and healthcare spending. Combination therapy is the treatment of choice for biofilm‐associated infections due to the simultaneous action of two drugs on two separate cellular targets and their safety. This study aimed to evaluate the effect of the combination of some bioactive natural products with conventional antibiotics against the biofilm of uropathogenic Staphylococcus spp. Antibacterial and antibiofilm activities were determined by the broth microdilution test. The checkerboard method was used for combination studies. The cytotoxicity of the best synergistic combinations was evaluated on Raw 264.7 macrophage cells and urinary epithelial cells (UROtsa) using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Plumbagin also showed the best biofilm‐inhibiting and eradicating activities compared to curcumin, berberine, thymol, quercetin, and gallic acid. The best synergistic combinations against biofilm inhibition and eradication were C1: cefixime (5.33 µg/mL) + thymol (32 µg/mL); C2: cefazolin (1.16 µg/mL) + thymol (21.33 µg/mL); C3: amikacin (0.18 µg/mL) + curcumin (37.33 µg/mL); C4: kanamycin (0.25 µg/mL) + curcumin (14 µg/mL); and C5: amoxicillin (1.16 µg/mL) + curcumin (21.33 µg/mL). Time‐kill studies revealed that the highest antibiofilm activities of the best combinations were observed at 24 h. Eradication activities were more significant than inhibitory activities. Compared to C3, C4, and C5 combinations, C1 and C2 combinations showed less cytotoxicity against the two tested cell lines UROtsa and Raw 264.7. This study shows that the best antibiofilm synergistic effect was obtained with the combination of thymol with cefixime and cefazolin, associated with low cytotoxicity. These associations could be considered potential candidates for the development of combination therapies against Staphylococcus spp. biofilm‐associated infections. While this study demonstrates promising in vitro results, further in vivo validation is necessary to confirm the efficacy and safety. Additionally, mechanistic studies are needed to understand the synergistic pathways, and future research should address scalability and formulation for clinical use.