Antibacterial activity of hypocrellin A against Staphylococcus aureus

Abstract

The antibacterial activity and acting mechanism of hypocrellin A (HA) were conducted regarding in vitro activity of HA on Staphylococcus aureus GZ86 by analyzing the growth, permeability, and morphology of the bacterial cells following treatment with HA. The experimental results indicated 1.5 mg/l HA could completely inhibit the growth of 10⁷ CFU/ml S. aureus cells in liquid beef extract-peptone medium under a halogen-tungsten lamp for 120 min. Meanwhile, HA resulted in the leakage of reducing sugars and proteins and induced the respiratory chain dehydrogenases into inactive state, suggesting that HA were able to destroy the permeability of the bacterial membranes. When the cells of S. aureus were exposed to 2.5 mg/l HA under a halogen-tungsten lamp for 120 min, many pits and gaps were observed in bacterial cells by scanning electron microscopy, and the cell wall was fragmentary, indicating the bacterial cells were damaged severely. The experiments strongly confirmed the contribution of multiform reactive oxygen species (ROS) to bactericidal effect. In conclusion, the combined results suggested that ROS may damage the structure of bacterial cell wall and depress the activity of some membranous enzymes, which cause S. aureus bacteria to die eventually.

Chemical Composition, Antibacterial Activity, and Mechanism of Action of the Essential Oil from Amomum kravanh

“…The TEM micrographs of B. subtilis and E. coli cells treated with the essential oil of A. kravanh fruits showed that severe morphological alterations appeared in the cell wall and membrane, which have also been observed for various kinds of organisms when treated with different essential oils (3,7). The physical and morphological changes in bacterial cells might come from the effect of essential oil on the permeability of the cell membrane, resulting in lysis of the bacterial cell wall, followed by the loss of intracellular dense materials at the surface of treated cells.…”

Antibacterial Activity and Mechanism of Action of Black Pepper Essential Oil on Meat-Borne Escherichia coli

“…The measurement of the release of 260-nm absorbing materials from E. coli according to the method described by Du et al (2012) with some modifications. Cells from the 100 mL E. coli suspension were collected by centrifuging at 5,000 × g for 15 min, washed three times with 0.1 M PBS (pH 7.4), and resuspended in PBS (0.1 M, pH 7.4).…”

Nitric oxide mediates hypocrellin accumulation induced by fungal elicitor in submerged cultures of Shiraia bambusicola

“…is a parasitic fungus of bamboo that grows mainly in the southern provinces of China. It produces a range of perylenequinone compounds, including hypocrellin A (HA) and B. Hypocrellin possesses excellent light-induced antiinflammatory, analgesic, antibacterial, antitumor and antiviral activities (Du et al 2012). Application of elicitors from pathogenic fungi is an effective method to improve the productivity of useful secondary metabolites in plant cell cultures (Roberts and Shuler 1997).…”