Studies On The Chemical Composition And Anti-Rheumatoid Arthritis Activity Of Rhamnella Gilgitica Mansf.ET Melch

Rhamnella gilgitica Mansf. et Melch, also called euphorbia prolifera, belonging to the rhamnus family (Rhamnaceae), is traditionally used for the treatment of rheumatism, grabbing dry yellow water, swelling and pain. Previous phytochemical studies of R. gilgitica have reported on the isolation of several flavonoids, such as mexican methadone, naringenin, kaempferol, quercetin, chrysophanol, gallic acid, 8-sterols, mixed fatty acids and mixed fatty acid esters. However, little is known about the biological activities of this plant. As a part of ongoing research to identify natural products that can prevent rheumatoid arthritis, we have shown here that the R. gilgitica was shown to significantly reduce the inflammatory responses in vivo. Furthermore, I have isolated four compounds from the heartwood of R. gilgitica. The results are as follows:1. Pulverized heartwood of R. gilgitica were extracted with 70% EtOH under reflux and the extract was concentrated in vacuo to obtain 70% EtOH extract. The extract was suspended in H2O, and the resulting H2O layer was partitioned with petroleum ether, dichloromethane, EtOAc, n-BuOH. These fractions were chromatographed on silica gel column with eluted with petroleum ether:EtOAc (100:1 �' 10:1) and dichloromethane-methanol (20:1 ～ 1:5,V/V) to give four organic compounds. Based on the 1H-NMR and 13 C-NMR data, the structures of these compounds were identified as ethylparaben(Ⅰ), hydroxybenzaldehyde(Ⅱ), naringenin (Ⅲ) and quercetin(Ⅳ). Among them, the isolation of Ethylparaben(Ⅰ) and hydroxybenzaldehyde(Ⅱ) from this plant has not been reported yet.2. Anti-oxidant activities of R. gilgitica were evaluated by Prussian blue, DPPH and Fenton assay. Results suggested that ethyl acetate and n-butyl alcohol-soluble fractions showed potent scavenging activities on DPPH radical in a dose-dependent manner, and exhibiting IC50 value of 0.0605 mg·mL-1 and 0.0763 mg·mL-1, respectively. The high polar fractions of R. gilgitica showed significant anti-oxidant activities.3. The analgesia and anti-inflammatory activities of R. gilgitica were evaluated by acetic acid twisting method and xylene-induced mice ear edam models. The results shows that the extracts of R. gilgitica were inhibited acetic acid induced writhing test and the ear swelling of caused by dimethylbenzene, and the extracts of ethanol is slightly higher than the ethyl acetate and n-butyl alcohol-soluble fractions. R. gilgitica extracts have obvious effects on analgesia and anti-inflammatory.4. The influence on rat rheumatoid arthritis by oral administration of R. gilgitica was studied. The rat models of adjuvant RA were made by Freund’s complete adjuvant. The treatment groups were treated with oral administration of different concentrations of ethanol extract of R. gilgitica. Compared with the model group, the treatment groups markly suppressed the arthritis index and obviously relieved the arthritis symptoms. In addition, the levels of white blood cell count and the index of erythrocyte sedimentation rate in the experimental rats were markedly lowered. Further detailed studies investigating the protective effects of R. Gilgitica in in vitro and in vivo models of RA would help to clarify its therapeutic potential.