Antimicrobial and Antioxidant activities of various extracts of Hyoscyamus albus L. and Umbilicus rupestris L. leaves

Our objectives were to investigate the antioxidant activity by the means of two methods: the β-carotene bleaching method and DPPH assay as well as testing the antimicrobial activity by the Agar-gel diffusion method and the microdilution method with liquid medium of the extracts (EEp, EChl and EMeOH) of the leaves of H. albus and (EEp, EChl and EMeOH) of U. rupestris. The quantitative analysis are showed that the highest content of total phenolic was concentrated in the butanolic extract of H.albus with 111 .1 ± 1.82 μg EAG/mg of extracts, in the second level the methanolic extract of U. rupestris with 105.7±0.37 μg EAG/mg of extracts. The content of flavonoids was determined by specrophotometry and showed the presence of these compounds in the all extracts from the two plants.

In the β-carotene bleaching test, the EMeOH of H.albus displayed highest antioxidant activity (76.00 %) and the EMeOH extract with a radical-scavenging activity (72.97%). On the other hand, the quantitative evaluation of the antiradical activity towards DPPH showed that the EMeOH of U. rupestris is the most active (IC₅₀ = 35.33 ± 0.136 μg/ml) followed by the EMeOH (IC₅₀ = 75.19 ± 0.211 μg/ml) of H. albus.

All the polar extracts of the two plants reacted positively at least on one of the bacterial strains tested. These extracts showed different activities and the CMI were determined starting from the most active extracts in gelose medium, Extract EBut  of H.albus testified to a strong antimicrobial activity followed by the EMe of U. rupestris. Results of the anticandidose activity showed the inefficiency of the all extracts against the yeast Candida albicans.