Microbiological and Mucociliary Properties of the Ethanol Extract ofHymenocardia acidaon Selected Respiratory Clinical Isolates

Saponaria officinalis L. extract: Surface active properties and impact on environmental bacterial strains

Plant-derived surfactants are characterised by low toxicity, high biodegradability and environmental compatibility. They therefore have many applications; for instance, they can be used in bioremediation to accelerate biodegradation processes, especially of hydrophobic pollutants. This paper analyses the properties of an extract from Saponaria officinalis L. containing saponins and its impact on bacterial strains isolated from soil, as well as its potential for application in hydrocarbon bioremediation. The tested extract from Saponaria officinalis L. contains gypsogenin, hederagenin, hydroxyhederagenin and quillaic acid aglycone structures and demonstrates good emulsification properties. Contact with the extract led to modification of bacterial cell surface properties. A decrease in cell surface hydrophobicity and an increase in membrane permeability were recorded in the experiments. An increase of up to 63% in diesel oil biodegradation was also recorded for Pseudomonas putida DA1 on addition of 1gL^-1 of saponins from Saponaria officinalis L. Saponaria extract showed no toxic impact on the tested environmental bacterial strains at the concentration used in the biodegradation process.

Cyclopeptide Alkaloids from Hymenocardia acida

Four cyclopeptide alkaloids (1-4) were isolated from the root bark of Hymenocardia acida by means of semipreparative HPLC with DAD and ESIMS detection and conventional separation methods. Structure elucidation was performed by spectroscopic means. In addition to the known compound hymenocardine (1), three other alkaloids were isolated for the first time from a natural source. These included a hymenocardine derivative with a hydroxy group instead of a carbonyl group that was named hymenocardinol (2), as well as hymenocardine N-oxide (3) and a new cyclopeptide alkaloid containing an unusual histidine moiety named hymenocardine-H (4). The isolated cyclopeptide alkaloids were tested for their antiplasmodial activity and cytotoxicity. All four compounds showed moderate antiplasmodial activity, with IC50 values ranging from 12.2 to 27.9 μM, the most active one being hymenocardine N-oxide (3), with an IC50 value of 12.2 ± 6.6 μM. Compounds 2-4 were found not to be cytotoxic against MRC-5 cells (IC50 > 64.0 μM), but hymenocardine (1) showed some cytotoxicity, with an IC50 value of 51.1 ± 17.2 μM.

Antibacterial chromene and chromane stilbenoids from Hymenocardia acida

Six chromene stilbenoids and one chromane stilbenoid were isolated from the African tree Hymenocardia acida. Several were moderately active against methicillin-resistant Staphylococcus aureus clinical isolate MRSA-108, including hymenocardichromanic acid, which was active at 8 μg/ml. None had IC50 values <20 μM in antiproliferation assays against several human cancer cell lines.