Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum （PCC） was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits （2.5-3.0 kg） were precontracted with phenylephrine （Phe, 10 pmol I^-1） and then treated with various concentrations of Cuscuta chinensis extract （1, 2, 3, 4 and 5 mg ml^-1）. The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay （RIA）. The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase （NOS） inhibitor （No〉 nitro-L-arginine-methyl ester, L-NAME）, a guanylyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-l-one, ODQ）, or a protein kinase A inhibitor （KT 5720） did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate （cGMP） and cyclic adenosine monophosphate （cAMP） in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction （ED）, which does not completely respond to sildenafil citrate.

Effect of the semen extract of Cuscuta chinensis on inflammatory responses in LPS-stimulated BV-2 microglia

AIM: To investigate the anti-inflammatory activities of the semen extract of Cuscuta chinensis Lam.(Cuscutae Semen; CS) on the production of inflammatory mediators, nitric oxide(NO), prostaglandin 2(PGE2), and proinflammatory cytokines in lipopolysaccharide(LPS)-stimulated BV-2 microglia. METHOD: BV-2 cells were treated with CS extract for 30 min, and then stimulated with LPS or without for 24 h. The levels of NO, PGE2 and proinflammatory cytokines were measured by Griess assay and ELISA. The expression of inducible nitric oxide synthase(iNOS), and cyclooxygenase(COX)-2 mRNA and protein was determined by RT-PCR and Western blot, respectively. The phosphorylation of extracellular signal-regulated kinase 1/2(ERK1/2), Jun N-terminal kinase(JNK), and p38 mitogen-activated protein kinase(MAPK), and the nuclear expression of nuclear factor(NF)-κB p65 were investigated by Western blot analysis. RESULTS: CS extract significantly decreased the production of NO and PGE2 by suppressing the expression of iNOS and COX-2 in activated microglia. CS extract decreased the production of TNF-α, IL-1β, and IL-6 by down-regulating their transcription levels. In addition, CS extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of NF-κB p65 in activated microglia. CONCLUSION: These results indicate that CS extract is capable of suppressing the inflammatory response by microglia activation, suggesting that CS extract has potential in the treatment of brain inflammation.

Authenticity Survey of Cuscutae Semen on Markets Using DNA Barcoding

Objective Using authentic raw herbal materials is fundamental to herbal medicine quality. Cuscuta chinensis and C. australis are two important species of Cuscutae Semen recorded in Chinese Pharmacopoeia. Due to having tiny bodies of seeds, it is extremely difficult to differentiate them from adulterants and closely related species by morphologic characteristics, leading to serious safety problems. Methods In this study, we developed a fast and efficient method to identify Cuscutae Semen on the market. First, a total of 207 ITS2 sequences representing 45 related species of Cuscutae Semen were collected to construct a standard DNA barcode database, then 33 commercial samples purchased from markets were analyzed by BLAST, and Neighbor-joining tree was used to verify the efficacy of the database. Results The percentage of counterfeits and adulterants in the 33 commercial samples were up to 69.7%, and only 10 commercial products were found to be genuine. The adulterated species included 11 species （Amaranthus hybridus, Brassica carinata, Brassica juncea var. megarrhiza, Chenopodium album, Corispermum heptapotamicum, Cuscuta alata, Cuscuta japonica, Cuscuta monogyna, Foeniculum vulgare, Glycine max, and Medicago sativa）. Conclusion DNA barcoding is a fast and efficient method to identify Cuscutae Semen on the market.