Yuhong ointment ameliorates inflammatory responses and wound healing in scalded mice

Yuhong ointment (YHO) is famous for its efficacy in clearing away heat and dampness, reducing swelling and relieving pain, and it has been used for more than 600 years. Scalding damages the skin's defense function, resulting in a large number of necrotic tissues and cells on the wound surface, which favors bacterial growth and inflammation. If the inflammation reaction is not controlled on time, it may lead to reduced immunity and cause complications such as infection. Yuhong ointment can promote wound healing in scalded mice, but its potential pharmacological mechanism is still unclear.

This study focused on identifying the active ingredients of YHO and on investigating the performance of YHO in terms of anti-inflammatory activity and scald wound healing activity.

High-performance liquid chromatography (HPLC) and high-performance liquid chromatography-mass spectrometry (HPLC-MS) were performed to identify the active ingredients of YHO. The performance of transdermal delivery of YHO was studied via HPLC for analyzing the ingredients of the exposed skin liquid of mice. Enzyme-linked immunosorbent assay (ELISA) analysis, immunohistochemistry, and real-time fluorescence quantitative PCR (qRT-PCR) were used to investigate the anti-inflammatory and scald wound healing activity of YHO.

A total of 41 components of YHO were identified via HPLC and HPLC-MS for the first time. In the transdermal delivery experiment, the cumulative amounts of chlorogenic acid, sesamol, ferulic acid, and L-shikonin were calculated to be 342.28, 567.89, 384.54, and 528.67 μg/cm², respectively. Pharmacological activity experiments indicated that these four kinds of drugs exhibited different degrees of therapeutic effects on scald. Specifically, YHO high-dose (YHO-H) group showed better therapeutic ability (P < 0.01) than FN and MB group. Furthermore, the immune function of the YHO group was enhanced due to the continuous increment of the levels of Hydroxyproline (HYP), Immunoglobulin G (IgG), and vascular endothelial growth factor (VEGF) and simultaneous decrement of the levels of TNF-α, TNF-β, IL-10, and IL-6 in the skin wound. Histological results showed that the thickening of skin tissue was alleviated after treatment with YHO. Moreover, the expression of substance P (SP), calcitonin gene related peptide (CGRP) and transient receptor potential vanilloid-1 (TRPV1) was inhibited, and the expression of VEGF was promoted by YHO (P < 0.01). The qRT-PCR test results indicated that the YHO group exhibited better inhibitory effect on interleukin 6 (IL-6), interleukin 10 (IL-10), transforming growth factor-beta (TGF-β), and Smad-3 mRNA expression levels than the other groups.

In this work, the active ingredients of YHO were identified via HPLC and HPLC-MS analysis. Importantly, YHO showed great advantages in transdermal delivery and scald wound healing, which can be attributed to the both anti-inflammatory and tissue regeneration mechanisms. Therefore, this work not only identified the active ingredients of YHO but also revealed the potential pharmacological mechanism of YHO for the healing of scald.