Identification of Antibacterial Components and Modes in the Methanol-Phase Extract from a Herbal Plant Potentilla kleiniana Wight et Arn

Abstract

The increase in bacterial resistance and the decline in the effectiveness of antimicrobial agents are challenging issues for the control of infectious diseases. Traditional Chinese herbal plants are potential sources of new or alternative medicine. Here, we identified antimicrobial components and action modes of the methanol-phase extract from an edible herb Potentilla kleiniana Wight et Arn, which had a 68.18% inhibition rate against 22 species of common pathogenic bacteria. The extract was purified using preparative high-performance liquid chromatography (Prep-HPLC), and three separated fragments (Fragments 1–3) were obtained. Fragment 1 significantly elevated cell surface hydrophobicity and membrane permeability but reduced membrane fluidity, disrupting the cell integrity of the Gram-negative and Gram-positive pathogens tested (p < 0.05). Sixty-six compounds in Fragment 1 were identified using Ultra-HPLC and mass spectrometry (UHPLC-MS). The identified oxymorphone (6.29%) and rutin (6.29%) were predominant in Fragment 1. Multiple cellular metabolic pathways were altered by Fragment 1, such as the repressed ABC transporters, protein translation, and energy supply in two representative Gram-negative and Gram-positive strains (p < 0.05). Overall, this study demonstrates that Fragment 1 from P. kleiniana Wight et Arn is a promising candidate for antibacterial medicine and food preservatives.

Antibacterial Ingredients and Modes of the Methanol-Phase Extract from the Fruit of Amomum villosum Lour.

“…Based on our recent studies [ 11 , 12 , 13 , 14 ], the M–CE method was employed to extract antibacterial substances from the fruit of A. villosum Lour. Its water loss rate was 73.68% after freeze-drying at −80 °C for 48 h. The extraction yields of the MPE and chloroform-phase extract (CPE) of A. villosum Lour.…”

“…The bacterial strains and media used in this study are shown in Table S7 . The incubation conditions of the bacterial strains were the same as those described in our recent reports [ 11 , 12 , 13 , 14 ].…”

“…The fruit is oval, purplish red when ripe, and brown after dry, with a unique and rich aroma. The antibacterial components in the samples were extracted using the M–CE method, as reported in our recent studies [ 11 , 12 , 13 , 14 ]. Briefly, the fresh samples were washed with water, cut into small pieces of about 1/4 size, and pre-frozen at −80 °C for 8 h. Thereafter, the samples were further freeze-dried, crushed, and extracted with the methanol–chloroform (2:1, v / v , analytical grade, Merck KGaA, Darmstadt, Germany) at a solid-to-liquid ratio of 1:10 ( m / v ) for 5 h. A certain amount of H 2 O (analytical grade) was added, sonicated, and filtered, and then the MPE and CPE were separated using the same equipment and parameters described in our recent reports [ 11 , 12 , 13 , 14 ].…”

“…were determined against the target strains. The definition of antibacterial activity and MICs were described in our recent reports [ 11 , 12 , 13 , 14 ].…”

“…In order to further explore the antibacterial activity of A. villosum Lour., in this study, we aimed to extract bioactive compounds in the fruit of A. villosum Lour. using the methanol–chloroform extraction (M–CE) method, which has been well established in our laboratory [ 11 , 12 , 13 , 14 ], and to decipher the antibacterial ingredients and modes of the methanol-phase extract (MPE) from A. villosum Lour.…”