Ethnopharmacological relevance: Four Indian plants, traditionally used in Ayurvedic medicine: Asparagus
racemosus Willd., Emblica officinalis Gaertn., Hemidesmus indicus R. Br., and Rubia cordifolia L. were
selected on the basis of their ethnobotanical use and of scientific evidence that suggests a potential
efficacy in the treatment of bone-loss diseases. The antiresorptive properties of the four plants have been
investigated. The aim was to provide adequate evidence for the exploitation of natural compounds as
alternative therapeutics for the treatment of diseases caused by increased osteoclast activity.
Materials and methods: Decoctions were prepared from dried plant material according to the traditional
procedure and standardization by HPLC was performed using marker compounds for each species. Total
polyphenols, flavonoids and radical scavenging activity of the decoctions were also determined. The
bioactivity of the plant decoctions was evaluated in subsequent phases. (1) A cytotoxicity screening was
performed on the mouse monocytic RAW 264.7 cell line to define the concentrations that could be
utilized in the following step. (2) The antiresorptive properties of plant decoctions were compared with
that of a “gold standard” drug (alendronate) by measuring osteoclastogenesis inhibition and osteoclast
apoptosis. (3) The toxic effect on bone forming cells was excluded by evaluating the impact on the
proliferation of osteogenic precursors (mesenchymal stem cells, MSC).
Results: All the decoctions inhibited osteoclastogenesis similarly to alendronate at the highest doses, but
Hemidesmus indicus and Rubia cordifolia were also effective at lower concentrations. Apoptosis increased
significantly when cells were exposed to the highest concentration of Emblica officinalis, Hemidesmus
indicus, and Rubia cordifolia. All concentrations of Emblica officinalis tested inhibited the proliferation of
osteogenic precursors, while only the highest doses of Asparagus racemosus and Rubia cordifolia were
toxic. On the contrary, Hemidesmus indicus did not affect osteogenic precursor growth at any concentration
tested.
Conclusion: Among the medicinal plants included in the study, Hemidesmus indicus showed the greatest
antiosteoclastic activity without toxic effect on osteogenic precursors. Therefore, Hemidesmus indicus
exhibits the properties of an antiresorptive drug and represents the ideal candidate for further clinical
investigations.