ABSTRACT
According to the World Health Organization, it is estimated that by 2050, drug-resistant infections could cause up to 10 million deaths annually. Therefore, finding a new generation of antibiotics is crucial. Natural compounds from endophytic fungi are considered a potential source of new-generation antibiotics. The antimicrobial and cytotoxic effects of ethyl acetate extracts of nine endophytic fungal isolates obtained from Hyssopus officinalis were investigated for bioassay-guided isolation of the natural compounds. An extract of isolate VII showed the highest antimicrobial activities against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus (30.12 ± 0.20 mm and 35.21 ± 0.20 mm) and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa (30.41 ± 0.23 mm and 25.12 ± 0.25 mm) among the tested extracts of isolates. Molecular identification of isolate VII confirmed it as Chaetomium elatum based on sequencing of its ITS genes, and it was discovered that this was the first time C. elatum had been isolated from H. officinalis. This isolate was cultured at a large scale for the isolation and identification of the active compound. Penicillic acid was isolated for the first time from C. elatum and its chemical structure was established by NMR spectroscopy. The penicillic acid showed strong antibacterial activities against Bacillus subtilis and Staphylococcus aureus with 20.68 mm and 25.51 mm inhibition zones, respectively. In addition, MIC and MBC values and antibiofilm activities of penicillic acid were determined. It was found that penicillic acid reduced the level of biofilms in proportion to antibacterial activity.
ABSTRACT
The structures and anticancer effects of two sesquiterpene lactones, 1 R,10S,3S,4R-diepoxyguai-5S,6S,7S-11(13)-en-6,12-olide (1) and hanphyllin (2) isolated from the aerial part of Tanacetopsis karataviensis (Kovalevsk.) Kovalevsk were investigated. The compound 1 was isolated for the first time as a natural compound and its structure was investigated by HR-ESI-MS, IR and NMR techniques. The X-ray diffraction analysis was performed to accurately determine the spatial structures of 1 and 2. Furthermore, we evaluated the cytotoxic activity of 1 and 2, and the chloroform fraction which contains both of them. Cytotoxic activity revealed that the effect of the chloroform fraction is stronger in growth inhibition of HeLa (89.7%) and HEp-2 (63.0%) cancer cells than the effect of individual compounds 1 (55.9 and 36.3%), 2 (78.6 and 50.3%) and the reference cisplatin (58.0 and 46.8%) respectively. Moreover, the chloroform fraction is less toxic to the hepatocytes.
