Comparative "in vitro" evaluation of the antiresorptive activity residing in four Ayurvedic medicinal plants. Hemidesmus indicus emerges for its potential in the treatment of bone loss diseases.
BACKGROUND
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.


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.


CONCLUSIONS
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.
Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopedic Institute, via di Barbiano 1/10, 40136 Bologna, Italy. Electronic address: gemma.dipompo@ior.it.
Gemma
G
Di Pompo
Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Irnerio 42, 40126 Bologna, Italy.
Ferruccio
F
Poli
Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Irnerio 42, 40126 Bologna, Italy.
Manuela
M
Mandrone
Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Irnerio 42, 40126 Bologna, Italy.
Beatrice
B
Lorenzi
Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopedic Institute, via di Barbiano 1/10, 40136 Bologna, Italy.
Laura
L
Roncuzzi
Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopedic Institute, via di Barbiano 1/10, 40136 Bologna, Italy; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Ugo Foscolo 7, 40123 Bologna, Italy.
Nicola
N
Baldini
Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopedic Institute, via di Barbiano 1/10, 40136 Bologna, Italy.
Donatella
D
Granchi
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000627:therapeutic use* / Q000633:toxicity; D001862:Bone Resorption / Q000473:pathology / Q000517:prevention & control*; D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D020834:Ethnopharmacology; D031102:Hemidesmus / Q000737:chemistry*; D006801:Humans; D008264:Macrophages / Q000187:drug effects; D008515:Medicine, Ayurvedic; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects* / Q000473:pathology; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000627:therapeutic use / Q000633:toxicity; D010946:Plants, Medicinal / Q000737:chemistry*; D013045:Species Specificity
D050071:Bone Density Conservation Agents; D010936:Plant Extracts
Asparagus racemosus; Bone resorption; Emblica officinalis; Hemidesmus indicus; Rubia cordifolia