Antiarthritic Effects of a Root Extract from Harpagophytum procumbens DC: Novel Insights into the Molecular Mechanisms and Possible Bioactive Phytochemicals

Alessia Mariano; Antonella Di Sotto; Martina Leopizzi; Stefania Garzoli; Valeria Di Maio; Marco Gullì; Pietro Dalla Vedova; Sergio Ammendola; Anna Scotto d'Abusco

doi:10.3390/nu12092545

Antiarthritic Effects of a Root Extract from Harpagophytum procumbens DC: Novel Insights into the Molecular Mechanisms and Possible Bioactive Phytochemicals

Nutrients. 2020 Aug 23;12(9):2545. doi: 10.3390/nu12092545.

Authors

Alessia Mariano¹, Antonella Di Sotto², Martina Leopizzi³, Stefania Garzoli⁴, Valeria Di Maio³, Marco Gullì², Pietro Dalla Vedova⁵, Sergio Ammendola⁶, Anna Scotto d'Abusco¹

Affiliations

¹ Department of Biochemical Sciences, Sapienza University of Roma, P.le Aldo Moro 5, 00185 Roma, Italy.
² Department of Physiology and Pharmacology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
³ Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino-Sapienza University, 04100 Latina, Italy.
⁴ Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
⁵ UOC di Ortopedia e Traumatologia, Ospedale Santa Scolastica di Cassino, ASL di Frosinone, Via S. Pasquale, 03043 Cassino, Italy.
⁶ Ambiotec S.A.S. Via Appia Nord 47, 04012 Cisterna di Latina (LT), Italy.

Abstract

Harpagophytum procumbens (Burch.) DC. ex Meisn. is a traditional remedy for osteoarticular diseases, including osteoarthritis (OA), although the bioactive constituents and mechanisms involved are yet to be clarified. In the present study, an aqueous H. procumbens root extract (HPE; containing 1.2% harpagoside) was characterized for its effects on synoviocytes from OA patients and phytochemical composition in polyphenols, and volatile compounds were detected. HPE powder was dissolved in different solvents, including deionized water (HPE_H2O), DMSO (HPE_DMSO), 100% v/v ethanol (HPE_EtOH100), and 50% v/v ethanol (HPE_EtOH50). The highest polyphenol levels were found in HPE_DMSO and HPE_EtOH50, whereas different volatile compounds, mainly β-caryophyllene and eugenol, were detected in all the extracts except for HPE_H2O. HPE_H2O and HPE_DMSO were able to enhance CB2 receptor expression and to downregulate PI-PLC β2 in synovial membranes; moreover, all the extracts inhibited FAAH activity. The present results highlight for the first time a multitarget modulation of the endocannabinoid system by HPE, likely ascribable to its hydrosoluble compounds, along with the presence of volatile compounds in H. procumbens root. Although hydrosoluble compounds seem to be mainly responsible for endocannabinoid modulation by HPE, a possible contribution of volatile compounds can be suggested, strengthening the hypothesis that the entire phytocomplex can contribute to the H. procumbens healing properties.

Keywords: FAAH; cannabinoid receptors; eugenol; nutraceuticals; osteoarthritis; phospholipases; polyphenols; volatile compounds; β-caryophyllene.

MeSH terms

Harpagophytum*
Humans
In Vitro Techniques
Osteoarthritis / drug therapy*
Phytochemicals / pharmacology*
Plant Extracts / pharmacology*
Plant Roots

Substances

Phytochemicals
Plant Extracts