Assessment of anti-inflammatory and anti-arthritic potential of ethanolic extract of Solanum nigrum L. leaves in CFA-induced arthritic rat model

Abstract

Objective: To investigate the anti-inflammatory and antiarthritic properties of Solanum nigrum (SN) leaves extract in rats induced with complete Freund’s adjuvant (CFA).

Methods: 30 male Wistar albino rats were used in a 4 weeks pre-clinical experimental trial, which were split up into 5 groups as; Group-1 Negative (healthy) control (0.9% normal saline), Group-2 positive (diseased) control (0.9% normal saline), Group-3 Standard (Methotrexate 1.5mg/kg), Group-4 (Solanum nigrum 100mg/kg), Group-5 (Solanum nigrum 200mg/kg). To develop rheumatoid arthritis, 0.1mL of Complete Freund’s Adjuvant was administered intraarticularly in the right knee joints of all groups except the Group-1 at day 0. Knee joint circumference was assessed by using a Vernier caliper once a week. On the 29th day, pentobarbital 100mg/kg was injected intraperitoneally to induce anesthesia in all animals, and a cardiac puncture was done to extract 8ml to 10ml of blood for further investigations. 4 to 5ml of that blood was centrifuged and serum was separated to perform Enzyme-linked immunosorbent assay (ELISA) to analyze the pro-inflammatory mediators including IL-1, IL-2, IL-6, TNF-? and prostaglandin E2. SPSS version 22 was used to analyze the results and for intergroup and intragroup comparison ANOVA was applied. P-value less than 0.05 was considered significant at 95% confidence interval.

Results: Knee joint circumference was significantly decreased in both standard and herbal groups when compared with the diseased controls, exhibiting SN efficacy as an anti-inflammatory agent. The ELISA showed a substantial rise in all pro-inflammatory cytokines in the positive control group. Both the herbal (G-4 & G-5) and standard (G-3) groups considerably reduced the levels of pro-inflammatory cytokines, while SN200 showed maximum decline in inflammatory markers.

Conclusion: Solanum nigrum can be used as an effective adjunctive with standard DMARDs like MTX to increase the efficacy in the treatment of RA.