UPLC-ESI-MS/MS Based Characterization of Active Flavonoids from Apocynum spp. and Anti-Bacteria Assay

Abstract

In the current study, the active flavonoids from Apocynum venetum and Apocynum hendersonii leaf were efficiently characterized using UPLC-ESI-MS/MS, and yielding the highest content of 15.35 mg/g (A. venetum) and 13.28 mg/g (A. hendersonii) respectively. The antioxidant assay in vitro showed that the isolated flavonoid ingredient groups exhibited free radical scavenging activities to DPPH, ABTS and linoleic acid. The antimicrobial assay revealed the isolated flavonoid ingredient from both A. venetum and A. hendorsonii have exerted anti-MRSA and anti-P. aeruginosa effect through disrupting cell integrity and declining ATP. In vivo assay demonstrated that these flavonoid ingredients effectively accelerated MRSA-infected and P. aeruginosa-infected Balb/c mice wound healing. In summary, these results showed that the characterized flavonoid ingredients exhibited great potential as natural antioxidant and antimicrobial agents, and shed light into future potential applications of Apocynum spp.

Total Flavonoids Extracts of Apocynum L. from the Ili River Valley Region at Different Harvesting Periods and Bioactivity Analysis

“…The zones of inhibition diameters for A. venetum extracts against E. coli , MARS , and A. niger were 11.20 mm, 9.81 mm, and 7.96 mm, while that of A. hendersonii were 17.80 mm, 13.99 mm, and 10.09 mm, respectively ( Figure 2 B). Compared to A. venetum , the A. hendersonii extract exhibited a larger inhibition zone, indicating better antimicrobial activities against all three strains, consistent with the results of Gao et al [ 21 ]. The leaves of Apocynum L. collected from the Ili River Valley region of Xinjiang demonstrated a relatively higher total flavonoids content and bioactivity on the microbes ( A. niger , fungi; E. coli , gram-negative bacteria, and MARS, gram-negative bacteria).…”

“…The extracts with the highest flavonoid contents (August harvest samples) for each species were selected for antibacterial assay and subsequent analysis. The in vitro inhibition assay was tested using the procedure described by Gao et al [ 21 ]. The fungi, Aspergillus niger (ATCC 33591, Manassas, VA, USA) single colonies grown in Potato Dextrose Agar (PDA) solid medium (4.0% PDA, Solarbio, Beijing, China), were picked out and dispersed in 10 mL of fresh potato dextrose broth (2.5% PDB, Solarbio) and incubated at 28 °C, 200 rpm for 8 h. Escherichia coli (ATCC 25922) and Methicillin-resistant Staphylococcus aureus (ATCC 11632) were cultured in Luria Bertani (LB) solid medium (1% NaCl, 0.5% yeast extract, 1% tryptone and 1.5% agar, pH 6.8) or fresh LB liquid medium at 37 °C, and other conditions were the same as the fungi.…”

“…The major cultivated species of Apocynum are divided into Apocynum venetum and Apocynum hendersonii ( Figure 1 A), which are excellent raw materials for both textiles and medicine, as well as pioneer crops for ecological restoration of saline soil and controlling desertification [ 8 , 20 ]. The biological activity of Apocynum L. has been associated with its rich flavonoids [ 21 ]. However, there are marked differences in total flavonoids and bioactivity between A. venetum and A. hendersonii , which require in-depth study to unravel the causes or stages.…”

Integrated multiomic study on the evolution and natural variation of flavonoid biosynthesis in Apocynum venetum and Apocynum hendersonii

“…Because of their similar geographical distribution, A. venetum and A. hendersonii are usually confused; however, there are distinct differences between the two species, with the former having a red-colored stem and flower with relatively broader leaves (Abubakaret al , 2022). These stem and flower colors may be due to differences in the functional expression of anthocyanins, as recent findings have shown A. venetum has the highest flavonoid content (Gao et al , 2021).…”

“…The natural variation in flavonoids between A. venetum andA. hendersonii (Chan et al , 2015;Gao et al , 2021) implies that a comparative analysis of the two species could provide insight into the mechanistic themes. Therefore, elucidating the mechanism underlying flavonoid biosynthesis is critical forApocynum breeding.…”