Anti-inflammatory and analgesic activities of the saponin, Daucosterol, and the triterpenoid ester, β-sitosterol 3-myristate, from Capparis erythrocarpos(Isert) Capparaceae, and their interaction with TRPV1 ion channel transporter

Capparis erythrocarpos root is an essential medicinal plant used in African traditional medicine as anti-arthritic, anti-inflammatory and analgesic agent. However, the chemical constituents in the plant responsible for its anti-inflammatory and analgesic activities were not known. This study reports on the isolation, characterization, anti-inflammatory and analgesic activities, of chemical constituents from the root bark of C. erythrocarpos . And also, determined the effect of these compounds on TRPV1 ion channels. The isolated compounds which were characterized as Daucosterol (DC) and β-sitosterol 3- myristate (SM). DC significantly (P < 0.05) inhibited both phase 1 and phase 2 of carrageenan-induced edema inverse dose-dependently with anti- inflammatory activity of 58.38% at 2 mg/kg p.o. SM only inhibited the phase 2 of carrageenan-induced edema with anti-inflammatory activity (P < 0.05) of 22.57% at 2 mg/kg p.o. Furthermore, DC significantly (P < 0.05) inhibited the cold-induced and mechanical pains with analgesic activities of 257.30 ± 33.13% at 8 mg/kg p.o. and 47.37% at 2 mg/kg p.o. respectively. The analgesic activity calculated for SM under the same treatment was 201.80 ± 32.39% or 26.32% against cold-induced and inflammatory pains respectively. Diclofenac sodium (DC) 8 mg/kg p.o. (standard drug) produced significant (P < 0.05) anti-inflammatory activity of 53.07%, analgesic activity of 134 ± 19% against cold-induced pain and 42.11% against inflammatory pain respectively. DC and SM produced ∆G of -10.60 and 9.80 kcal/mol which were higher than 8.6 kcal/mol produced by DS in the molecular dynamic simulation studies. This indicates that the primary mode of action of DC and SM are through the TRPV1 ion channel whereas, DS have another mode of action apart from TRPV1 inhibition. These results indicates that Daucosterol and β-sitosterol 3-myristate possessed remarkable anti-inflammatory and analgesic activities. Daucosterol and β-sitosterol 3-myristate could therefore, be explored for the development of new analgesic and anti-inflammatory drugs.