Asian Pacific Journal of Tropical Biomedicine

411-420

Authors: William Yousseu Nana, Ernest Allah Hoki Kwenteh, Gilbert Ateufack, Eric Gonzal Tsafack, Stephanie Flore Djuichou Nguemnang, Zenab Linda Fagni Njoya, Albert Donatien Atsamo, Vanessa Mba Matah Marthe, Carine Flore Adjouzem, Yacine Karelle Madjo Kouam, Elvira Ngoufack Azanze, Marius Mbiantcha

Objective: To evaluate the anti-arthritic effect of aqueous and methanolic extracts of Distemonanthus benthamianus. Methods: Monoarthritis was induced by an injection of 0.3 mL zymosan A (0.9% NaCl, v/v) in the right posterior knee joints of rats. Then, joint diameter and pain threshold were determined. Polyarthritis was induced by an intracaudal injection of complete Freund’s adjuvant and rats were treated from day 14 post 1st complete Freund’s adjuvant injection until 28 day. The clinical, hematological, biochemical and oxidative stress parameters were evaluated. In addition, histological analysis of the knee joint was perfomed in both tests. Results: The aqueous and methanolic extracts of Distemonanthus benthamianus at a dose of 500 mg/kg ameliorated zymosan A-induced monoarthritis, as evidenced by reduced joint diameter, increased pain threshold, as well as improved joint architecture. In addition, both extracts of Distemonanthus benthamianus markedly increased body weight and pain threshold, while reducing paw edema in polyarthritic rats. They also led to a marked decrease in platelets and white blood cells (P<0.05), as well as a significant increase in red blood cells, hemoglobin and hematocrit (P<0.05). The aqueous and methanolic extracts of Distemonanthus benthamianus significantly reduced alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase activities, while increasing serum protein levels (P<0.05) with no significant variation in creatinine level. Moreover, both extracts increased catalase and glutathione activities (P<0.05), and inhibited malondialdehyde and nitric oxide production (P<0.01 and P<0.001) in the liver and kidneys. Histological analysis of the joints showed that both extracts triggered tissue reparation. Conclusions: Distemonanthus benthamianus could be used as a potential candidate in the treatment of rheumatoid arthritis.

430-436

Authors: Hyun Ji Eo, Da Som Kim, Gwang Hun Park

Objective: To elucidate the potential anti-inflammatory mechanisms of Rhamnus crenata leaf extracts using RAW264.7 cells. Methods: We used 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay to measure cell viability. Nitric oxide (NO) production was measured using Griess reagent. Western blotting and RT-PCR assays were carried out for analyzing the protein and gene expressions of pro-inflammatory mediators, respectively. Moreover, PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), and BAY11-7082 (NF-κB inhibitor) were used to evaluate the anti-inflammatory mechanism of Rhamnus crenata leaf extract. Results: Rhamnus crenata leaf extracts significantly inhibited the production of the pro-inflammatory mediators such as NO, iNOS, COX-2, IL-1β, and TNF-α in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Rhamnus crenata leaf extracts also suppressed LPS-induced degradation of IκB-α and nuclear accumulation of p65, which resulted in the inhibition of NF-κB activation in RAW264.7 cells. Additionally, the extracts attenuated the phosphorylation of p38, ERK1/2, and JNK in LPS-stimulated RAW264.7 cells. Moreover, HO-1 expression induced by Rhamnus crenata leaf extracts was significantly downregulated by SB230580, PD98059, SP600125 and BAY11-7082. Conclusions: Rhamnus crenata leaf extract may upregulate HO-1 expression through inhibition of p38, ERK1/2, and NF-κB activation, which may contribute to the anti-inflammatory activity of the extracts. Rhamnus crenata leaf extracts may have great potential for the development of anti-inflammatory drugs to treat acute and chronic inflammatory diseases.

446-452

Authors: Fairouz Sioud, Mouna Maatouk, Imen Mokdad Bzeouich, Leila Chekir Ghedira, Soumaya Kilani-Jaziri

Objective: To evaluate the effects of phenolic acids (caffeic, ferulic, and coumaric acids) and flavones (luteolin and apigenin) on the proliferation and melanogenesis in murine melanoma B16-F10 cells. Methods: Cell proliferation was determined after 24 and 48 hours of incubation using MTT assay. The effects of these tested compounds on cell cycle progression were analyzed by flow cytometry. Moreover, the melanin content and tyrosinase activity were measured spectrophotometrically at 475 nm. Results: Luteolin and apigenin exhibited significant anti-proliferative activity against B16-F10 cells, while caffeic, ferulic, and coumaric acids induced slight inhibition after 24 and 48 hours of incubation. The tested compounds disturbed cell cycle progression of B16-F10, by a subsequent decrease in G1 and arrested cycle progression in either G1/S or G2/M phase. Furthermore, apigenin provoked an increase in melanin content of B16-F10 cells. In contrast, luteolin, caffeic, ferulic and coumaric acids induced a decrease in melanin content of B16-F10 cells by inhibiting tyrosinase activity. Conclusions: These active polyphenols may be used as skin whitening agents or natural tanning agents to treat skin pigmentation disorders.