Results published in Phytomedicine indicate that extracts from pomegranate fruit (Punica granatum L.) and grape seed (Vitis vinifera L.) may work by affecting gene expression linked to reduced osteoclast activation (osteoclasts are cells which break down bone, leading to resorption and weakening).
On the other hand, quercetin (Dimorphandra mollis Benth) and licorice extracts (Glycyrrhiza glabra L.) may promote bone formation by modulating gene expression linked to increased osteoblast activation (osteoblasts are cells responsible for bone formation).
“These results demonstrate that the two botanical extract combinations developed through a targeted series of in vitro and in vivo assays caused changes in gene expression indicating that osteoclastic and osteogenic processes were modulated with both,” wrote researchers led by Kevin Gellenbeck from the Nutrilite Health Institute.
Working with scientists from Access Business Group (USA), The Himalaya Drug Company (India), and Yumei Consulting, Inc. (USA), the Nutrilite scientists assessed gene expression in an ex-vivo microarray analysis of mRNA obtained from blood samples of post-menopausal women following a 28-day open-label intervention study. Forty-six women were randomly assigned to one of three groups: a combination of extracts from pomegranate fruit and grape seed; a combination of quercetin and licorice extracts; or a combination of all four plant extracts.
Results showed that the combination of pomegranate and grape seed extracts affected bone resportion gene expression, possibly by inhibiting a pathway called the RANK-RANKL pathway. This pathway is already a recognized target for therapeutic agents in the treatment of osteoporosis, explained the researchers.
The quercetin and licorice extracts were found to affect genes expression linked to a reduction in osteoclast activity and to an increase in osteoblastic activity. This seemed to be partly linked to stimulation of the pathways linked to the formation of bone and collagen.
Interestingly, when all four extracts were combined, the changes to gene expression were different from when they were used in pairs. “The combination of all four plant extracts demonstrates that modulating both bone resorption and bone formation simultaneously is difficult, possibly due to multiple feedback systems balancing the osteoblast and osteoclast activity,” they said.
“In summary, this ex-vivo microarray study indicates that the two botanical extract combinations modulate gene expression for both osteoclastic and osteogenic processes.
“Further work is warranted to confirm these results and to investigate the effect of the botanical extracts on the differentially expressed genes and their functional relationship to bone metabolism,” they concluded.
Volume 23, Issue 1, Pages 18–26, doi: 10.1016/j.phymed.2015.11.011
“Bone health nutraceuticals alter microarray mRNA gene expression: A randomized, parallel, open-label clinical study”
Authors: Y. Lin et al.