Evaluation of a root extract gel from Urtica dioica (Urticaceae) as analgesic and anti-inflammatory therapy in rheumatoid arthritis in mice

Purpose: To develop and characterize an herbal gel prepared from methanol root extract of Urtica dioica (Urticaceae) (Stinging nettle) for the treatment of arthritis in mice. Methods: A methanol root extract from Urtica dioica was prepared, and a gel was then prepared using Carbopol 934. The prepared gel was subjected to various physical tests (color, appearance, pH, texture, viscosity) and in vivo evaluation, including primary skin irritation, analgesic, and anti-inflammatory tests, in arthritic mice and compared with 2 % indomethacin gel, which was used as standard. Results: The prepared herbal gel was of light gray color with a smooth texture. It showed a pH of 7.1 and a viscosity of 21.2 cps. The gel exhibited pseudoplastic rheology, as evidenced by shear thinning with increased shear rate. It was non-irritating to the skin in primary skin irritation test in mice and showed 55.05 % inhibition of paw edema in a carrageenan-induced hind rat paw edema model, comparable to that of the standard gel (53.93 %), after 24 h. The gel showed 58.21 % analgesia, versus 61.19 % analgesia for the indomethacin gel standard in writhing test. Conclusion: The topical gel from methanol root extract of U. dioica may be an efficacious and safe alternative to non-steroidal anti-inflammatory drugs in the treatment of rheumatoid arthritis but this requires further investigations to ascertain its safety and clinical efficacy.

Effect of Arisaema erubescens (Wall) Schott rhizome extract on rheumatoid arthritis

Purpose: To investigate the anti-arthritic activity of the water extract of Rhizoma Arisaematis (WERA) using a collagen II -induced arthritis (CIA) rat model. Methods: CIA was induced in male Sprague-Dawley rats by intradermal injection of bovine collagen II in Complete Freund’s Adjuvant. The rats were treated with daily oral doses of WERA (100, 200, and 400 mg/kg) for 21 consecutive days. Methotrexate (MTX, 3 mg/kg), used as a positive control, was administered orally 2 times/week for 3 weeks. The severity of arthritis was evaluated using indices of paw swelling, arthritic score, body weight, thymus index, and spleen index. In addition, the serum levels of IL-1β, IL-6, IL-10, and TNF-α were measured. Results: All doses of WERA significantly inhibited paw edema (p < 0.01), decreased arthritis scores (p < 0.01) and spleen index (p < 0.05), and alleviated the weight loss associated with CIA in rats. Furthermore, TNF-α, IL-1β, and IL-6 serum levels were significantly decreased (p < 0.05) by all doses of WERA. By contrast, IL-10 serum levels were markedly increased (p < 0.05). Conclusion: WERA exerts therapeutic effects in CIA in rats by decreasing the serum levels of TNF-α, IL-1β, IL-6 and IL-10, suggesting WERA may be an effective candidate drug for treating human rheumatoid arthritis.

Antipyretic, analgesic and anti-inflammatory activities of methanol extract of root bark of Acacia jacquemontii Benth (Fabaceae) in experimental animals

Purpose: To investigate the ethnomedicinal claims regarding the use of Acacia jacquemontii Benth. (Fabaceae) in fever, pain and inflammation. Methods: The methanol root bark extract (AJRBM) of the plant was used in the studies. Preliminary phytochemical screening of the extract was carried out according to established methods. Analgesic, anti-inflammatory and antipyretic activities were evaluated using acetic acid-induced writhing, carrageennan-induced rat paw edema and Brewer’s yeast-induced pyrexia models, respectively. The extract was administered at doses of 50 and 100 mg/kg. Aspirin (300 mg/kg, p.o.) was used as a reference drug in all models. Normal saline (10 mL/kg p.o.) was used as negative control. Results: Phytochemical screening results indicate the presence of cardioactive glycosides, tannins, flavonoids and saponins. In the acetic acid-induced writhing model, the methanol extract exhibited significant (p < 0.05) analgesic effect with 58.98 % reduction in writhing response at a dose of 100 mg/kg, compared with untreated control group. The extract significantly (p < 0.05) reduced carrageenan-induced edema at doses of 50 and 100 mg/kg to 36.84 and 47.36 %, respectively, after 1 h of extract administration. The extract exhibited predominantly dose-dependent antipyretic effect in Brewer’s yeast-induced pyrexia model. Maximum reduction in body temperature to 37.07 and 38.29 ºC at doses of 50 and 100 mg/kg, respectively, was observed, compared with untreated group (38.90 ºC) after 1 h, but this was not significant (p < 0.05). Conclusion: The plant extract exerts inhibitory effect on peripheral pain stimuli, edema and dosedependent anti-pyrexia, and thus justifies the ethnomedicinal use of Acacia jacquemontii Benth. in the management of pain, fever and inflammation.