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

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.

Bacterial Strain for Bast Fiber Crops Degumming and Its Bio-Degumming Technique

The R&D of bio-degumming technology is under a slow progress due to the shortage of proper efficient bacterial strains and processes. A degumming bacterial strain—Pectobacterium wasabiae (PW)—with broad-spectrum degumming abilities was screened out in this study. After the fermentation for 12 h, the residual gum contents of kenaf bast, ramie bast, hemp bast, flax bast, and Apocynum venetum bast were all lower than 15%. This bacterial strain could realize the simultaneous extracellular secretion of pectinase, mannase, and xylanase with the maximum enzyme activity levels of 130.25, 157.58, and 115.24 IU/mL, respectively. The optimal degumming conditions of this bacterial strain were as follows: degumming time of 12 h, bath ratio of 1:10, temperature of 33 ℃, and inoculum size of 2%. After the bio-degumming through this bacterial strain, the COD in wastewater was below 4,000 mg/L, which was over 60% lower than that in boiling-off wastewater generated by chemical degumming. This technology achieves higher efficiency, higher quality, and lower pollution.