Triterpenoids and steroids isolated from Anatolian Capparis ovata and their activity on the expression of inflammatory cytokines

Context: Capparis L. (Capparaceae) is grown worldwide. Caper has been used in traditional medicine to treat various diseases including rheumatism, kidney, liver, stomach, as well as headache and toothache.

Objective: To isolate and elucidate of the secondary metabolites of the C. ovata extracts which are responsible for their anti-inflammatory activities.

Materials and methods: Buds, fruits, flowers, leaves and stems of C. ovata Desf. was dried, cut to pieces, then ground separately. From their dichloromethane/hexane (1:1) extracts, eight compounds were isolated and their structures were elucidated by NMR, mass spectroscopic techniques. The effects of compounds on the expression of inflammatory cytokines in SH-SY5Y cell lines were examined by qRT-PCR ranging from 4 to 96 µM. Cell viability was expressed as a percentage of the control, untreated cells.

Results: This is a first report on isolation of triterpenoids and steroids from C. ovata with anti-inflammatory activity. One new triterpenoid ester olean-12-en-3β,28-diol, 3β-pentacosanoate (1) and two new natural steroids 5α,6α-epoxycholestan-3β-ol (5) and 5β,6β-epoxycholestan-3β-ol (6) were elucidated besides known compounds; oleanolic acid (2), ursolic acid (3), β-sitosterol (4), stigmast-5,22-dien-3β-myristate (7) and bismethyl-octylphthalate (8). mRNA expression levels as EC₁₀ of all the tested seven genes were decreased, particularly CXCL9 (19.36-fold), CXCL10 (8.14-fold), and TNF (18.69) by the treatment of 26 µM of compound 1 on SH-SY5Y cells.

Discussion and conclusions: Triterpenoids and steroids isolated from C. ovata were found to be moderate-strong anti-inflammatory compounds. Particularly, compounds 1 and 3 were found to be promising therapeutic agents in the treatment of inflammatory and autoimmune diseases.

Keywords: 3β-pentacosanoate; Capparaceae; anti-inflammatory; anticholinesterase; fatty acid; olean-12-en-3β, 28-diol; secondary metabolites; spectroscopy; structure elucidation.