Rumex crispus, a natural drug against osteoporosis
Along roadsides and at the edges of fields and meadows grows a weed that may one day be used as an anti-osteoporosis drug. According to animal and test tube studies by Korean scientists, a water extract of curly sorrel inhibits the breakdown of bone tissue.
Rumex crispus
Researchers at the Korea Institute of Oriental Medicine experimented with a water-based extract of Rumex crispus, as curly sorrel is officially called. The Koreans made the extract themselves. The three main bioactive compounds in this extract were the anthraquinones emodin, chrysophanol and physcion.

Animal study

The researchers injected mice with RANKL for two days. RANKL is a protein that activates osteoclasts - the bone cells that break down tissue.For the following 5 days, the researchers additionally gave some of the mice a water-based extract of curly sorrel twice a day. If the mice had been humans, they would have received a dose of 2 grams of extract twice daily.
Although you can eat sorrel as a vegetable, daily supplementation with sorrel extract is not automatically safe. Sorrel also contains a lot of oxalate, and not everyone reacts well to it. If you are going to experiment with sorrel, make sure you get your hands on a product with reduced concentrations of oxalate.
The extract [WERC] reduced the effect of RANKL on bone volume [BV/TV], bone density [BMD], and bone strength [Tb.N].

In vitro studies
The researchers exposed osteoblasts - which are the cells in bone that build tissue - to the Rumex crispus-extract. In doing so, they figured out at least part of the mechanism by which sorrel inhibits osteoporosis. Sorrel switched on a number of genes that are active when osteoblasts build bone tissue, such as osteopontin and osterix.

This was mainly the work of the anthraquinones chrysophanol and physcion.
DM = growth medium.

The researchers did the same experiments with osteoclasts. They found that emodin, chrysophanol and physcion in sorrel actually inhibited genes involved in the breakdown of bone tissue. You can see this below.

"This suggests that a water extract of Rumex crispus could be used as a pharmacological candidate for traditional medicine in the prevention and treatment of osteoporosis", summarize the Koreans.

BMC Complement Altern Med. 2017 Oct 26;17(1):483.