In the course of doing research into means to obtain anti-inflammatory effects, a friend told me that she would wrap her knee-joints in Cabbage leaves and that worked well for her. Internally, my skeptic alarms began ringing. However, upon doing a little searching, I turned up the article below.

The article proposes that "micro RNA" from other species might be responsible for the reported effect. I have never heard of such a thing and I should probably hold some skepticism in reserve. However, if true, this would be a radical departure in terms of biomedical mechanisms. I'm curious if the miRNA remains active in cabbage leaf extracts that are commercially available.

Here's an extract:
"Recently, the possibility of cross-kingdom gene expression regulation by miRNAs from other species (“xenomiRs&rdquo, specifically from plants, has acquired scientific meaning. Based on the one of oldest methods for dealing with inflammation via the use of cabbage leaf compresses, ..."
MicroRNAs (miRNAs) are a class of naturally occurring, small noncoding RNA molecules, usually 21–23 nucleotides long, that regulate the expression of genes in animals and plants at the posttranscriptional level. miRNAs interact with specific mRNAs through complementary base pairing to influence the translation or stability of the target mRNA molecule, typically downregulating the expression of the corresponding gene.

[ncbi.nlm.nih.gov]