Potential Anti-Inflammatory Components of Rhododendron molle G. Don Leaf Extracts in LPS-Induced RAW 264.7.

As a traditional Chinese medicine, Rhododendron molle G. Don has a long history of treating rheumatoid arthritis. In this study, RAW 264.7 cells induced by lipopolysaccharide (LPS) were established as cell inflammatory model to evaluate the anti-inflammatory activity of chloroform extract from R. molle leaves (CERL), ethyl acetate extract from R. molle leaves (EERL) and butanol extract from R. molle leaves (BERL) and analyze the potential anti-inflammatory components of R. molle. Potential anti-inflammatory components analysis of CERL were performed by HPLC and UHPLC-Q-TOF-MS. Prediction of potential anti-inflammatory components by molecular docking experiments. Compared with negative control group, 25 µg/mL CERL could reduce the release level of NO by 62 %, and the mRNA expression levels of COX-2, IL-6, IL-1ß and TNF-α were reduced by 69.74 %, 86.25 %, 77.94 % and 56.80 %, respectively. Western-Blot showed similar results. CERL, EERL and BERL exerted their inhibitory activity in dose-dependent manner. All results showed that the higher the concentration, the better the anti-inflammatory activity. CERL showed the best inhibitory activity, the second was EERL, and then was BERL. 21 terpenoids and 4 flavonoids were identified in CERL by UHPLC-Q-TOF-MS. Molecular docking results showed that triterpenoids in CERL had better interaction with target proteins (TNF-α, IL-1ß). It indicated that triterpenoids may be potential anti-inflammatory components of R. molle leaves. This study explored the anti-inflammatory activities of CERL, EERL, BERL, which laid a foundation for further promoting the clinical application of R. molle.

Anti-rheumatoid arthritis potential of Rhododendron molle G. Don leaf extract in adjuvant induced arthritis rats.

AIM OF THE STUDY: The aim of this study was to test the anti-rheumatic arthritis effects of Rhododendron molle G. Don leaf extract in arthritis rats and inflammatory RAW 264.7 cells. Preliminary analysis and comparison of potential medicinal components of three polar extracts by HPLC and UHPLC-Q-TOF-MS. MATERIALS AND METHODS: SD rats were subcutaneously injected with complete Freund's adjuvant (CFA) to induce inflammation on the right hind paw. RAW 264.7 cells were induced by lipopolysaccharide (LPS) to established cell inflammatory model. The volume of rat hind paw was measured with a volume meter to detect swelling, and the weight of rats was measured with an electronic balance. The severity of arthritis in rats was evaluated by arthritis score. The pathological sections of rat hind paw joints were observed by hematoxylin-eosin staining, and the contents of IL-6 and IL-1ß in serum were detected. qRT-PCR was used to detect the expression of IL-1ß, IL-6, TNF-α and COX-2 genes in RAW 264.7 cells. The release of nitric oxide was measured by Griess reaction. The expression levels of IL-6 and IL-1ß were detected by Western-Blot. RESULTS: and discussion: The chloroform extract from R. molle leaves (CERL), Ethyl acetate extract from R. molle leaves (EERL), n-butanol extract from R. molle leaves (BERL) could significantly inhibit hind paws swelling and reduce arthritis index in arthritis rats. And it showed dose dependence. Compared with tripterygium glycosides (TG) tablets, an effective drug of RA treatment, CERL have better anti-RA effect after administration. In addition, the three kinds of the polar extracts of Rhododendron molle leaves (PERL) had lower toxicity, with the LD50 279.87, 239.65, 500.08 (mg/kg) respectively, while TG group's LD50 was 96.00 (mg/kg). In vitro experiments showed that the three PERLs can significantly inhibit the level of pro-inflammatory factors and inflammatory mediator, such as TNF-α, IL-1ß, IL-6, COX-2 and NO, which were consistent with their anti-RA ability. Among the three kinds of PERLs, CERL showed the best inhibitory activity. CONCLUSION: The R. molle leaf is a potential medicinal part for the treatment of RA. This study explored the anti-RA and anti-inflammatory activities of CERL, EERL, BERL, which laid a foundation for further promoting the clinical application of R. molle.

Rhododendron molle G. Don Extract Induces Apoptosis and Inhibits Migration in Human Colorectal Cancer Cells and Potential Anticancer Components Analysis.

Rhododendron molle G. Don is one example of traditional Chinese medicine with important medicinal value. In this study, the effects of methanol extract of R. molle leaves (RLE) on colorectal cancer HT-29 cells and its potential molecular mechanism were investigated. MTT analysis showed that RLE could significantly inhibit the cell viability and migration of HT-29 cells in a concentration-dependent manner. Cell cycle analyses via flow cytometer suggested that RLE induced DNA fragmentation, indicative of apoptosis, and arrest at the S phase in HT-29 cells. Quantitative real-time PCR (qRT-PCR) analysis showed that RLE could upregulate the mRNA expression of p53 and p21 in HT-29 cells, which would result in HT-29 cells being blocked in S phase. Meanwhile, RLE could upregulate the expression of Bax, and downregulate the expression of Bcl-2, which would induce cell apoptosis. Further western blot analysis showed that the protein expression changes of Bax and P53 were basically consistent with the results of qRT-PCR. In addition, GC-MS analysis detected 17 potential anticancer components in R. molle. These results indicate that R. molle has significant anticancer activity, which provides some useful information for further study and clinical application for R. molle.