Different types of effective fractions from Radix Isatidis revealed a multiple-target synergy effect against respiratory syncytial virus through RIG-I and MDA5 signaling pathways, a pilot study to testify the theory of superposition of traditional Chinese Medicine efficacy.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Isatidis, a commonly used traditional Chinese medicine, is also documented in "Dictionary of Chinese Ethnic Medicine" being as an ethnic herb clinically utilized by different nations in China such as Mongol, Uygur, and Dong et al. It has been reported to have a very strong efficacy on respiratory viruses, but to date the mechanism remains unknown. Similarly, it is unclear how different types of effective fractions of Radix Isatidis interact to exert antiviral effects. AIM OF STUDY: To reveal the underlying mechanisms for the inhibitory effects of three active fractions from Radix Isatidis, i.e. total alkaloids, lignans and organic acids, on respiratory syncytial virus when used alone or in combination. In addition, we investigated whether these three parts worked synergistically in vivo and in vitro. MATERIALS AND METHODS: A mouse model of RSV infection was constructed by intranasal infection, and the pathological changes of lung tissues in different parts were observed. The level changes of IFNß and inflammatory cytokines in the mouse alveolar lavage fluid were detected by enzyme-linked immunosorbent assay (ELISA). The anti-RSV effects of different effective fractions were evaluated by the plaque reduction test. The mRNA and protein expressions of RIG-I, MDA-5, MAVS and IRF3 in RAW264.7 cells were detected by RT-PCR and Western blot respectively. RESULTS: HE staining showed that Radix Isatidis extracts alone or in combination relieved virus-induced mouse lung lesions. Compared with individual drugs, the lung lesions were alleviated more significantly after treatment with the three fractions in combination. ELISA demonstrated that the expression levels of IFNß and inflammatory cytokines were maintained balanced between antiviral and proinflammatory effects. The plaque reduction test indicated that the antiviral effect of combination treatment was much stronger than those of individual drugs. RT-qPCR and Western blot suggested that the mRNA and protein expression levels of key signaling molecules in the RIG-I and MDA5 pathways in mouse macrophages were down-regulated by different effective parts alone or in combination. CONCLUSIONS: The three effective fractions of Radix Isatidis have remarkable synergistic anti-RSV effects in vitro and in vivo, and total alkaloids and lignans show multi-target synergistic effects via the RIG-I and MDA5 signaling pathways.

4(3H)-Quinazolone regulates innate immune signaling upon respiratory syncytial virus infection by moderately inhibiting the RIG-1 pathway in RAW264.7 cell.

The root of Isatis indigotica, also known as Ban-Lan-Gen (BLG), is commonly used for prevention and early treatment of respiratory virus infection, but the underlying mechanisms of action remain unclear. In the early stage of infection, the innate immune system is activated by virus, and related immune cells such as macrophages secrete large amounts of cytokines including IFNs and ILs. On the one hand, these cytokines can remove virus. On the other hand, they dominantly mediate the inflammatory injury caused by viral infection. This study evaluated the effects of the main active plasma components of BLG (tryptanthrin B, 4(3H)-Quinazolone and epigoitrin) on the innate immune response of respiratory syncytial virus (RSV)-activated mouse macrophages. ELISA, real-time PCR and reporter gene assay all showed that 4(3H)-Quinazolone inhibited RSV-induced IFN-ß secretion in mouse macrophages in a dose-dependent manner within a concentration range (0.3125-1.25µM) having no effects on cell viability, but the inhibitory effects were inferior to those of ribavirin. Western blot analyses further revealed that 4(3H)-Quinazolone inhibited RSV-induced expression of RIG-I (Retinoic acid-Inducible Gene-I) in mouse macrophages dose-dependently, thereby suppressing the transcription of IFN-ß, with lower effects than those of ribavirin. This may be one of the important mechanisms by which BLG inhibited inflammatory injury without affecting the immune system to eliminate virus. The results inspire future studies to elucidate the antiviral mechanisms of traditional Chinese medicine drugs.

Pleiotropic effects of herbs characterized with blood-activating and stasis-resolving functions on angiogenesis.

Accumulative evidences have underpinned the nature candidates from Chinese medicine (CM), particularly CM served as blood activating and stasis resolving (BASR, Huoxue Huayu in Chinese) by targeting tumor-associated angiogenesis. However, recent experiment research on the therapeutic angiogenesis by BASR-CM attracts wide attention and discussion. This opinion review focused on the underlying link between two indications and anticipated that (1) BASR-CM might emphasize on a balanced multi-cytokines network interaction; (2) BASR-CM might address on the nature of diseases prior to differently affecting physiological and pathological angiogenesis; (3) BASR-CM might mainly act on perivascular cells, either promotes arteriogenesis by increasing arteriogenic factors in ischemic diseases, or simultaneously keep a quiescent vasculature to impede angiogenesis in tumor context.

Effect of aqueous extracts of several kinds of herbs on human platelet aggregation and expression of P-selectin in vitro.

OBJECTIVE: To study the effect of aqueous extract of several kinds of herbs on human platelet aggregation and expression of P-selectin in vitro. METHODS: Blood was collected from volunteers. Effects of the prepared water extracts of herbs on platelet aggregation were monitored on a Packs-4 aggregometer. The fluorescence intensity of water extracts of Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae on the expression of P-selectin in human platelets of healthy persons was measured with flow cytometry. RESULTS: Out of several herbs investigated, Flos Carthami and Rhizoma Curcumae potently inhibited platelet aggregation after incubation with platelet-rich plasma (PRP) for 15 min. Caulis Spatholobi Flos Carthami and Rhizoma Curcumae inhibited adenosine-5'-diphosphate (ADP) or platelet activating factor (PAF)-induced platelet aggregation in PRP in a dose-dependent manner. In contrast to Flos Carthami and Rhizoma Curcumae, Caulis Spatholobi could not inhibit thrombin-induced platelet aggregation. Despite its inability to inhibit thrombin-induced platelet aggregation in PRP, Caulis Spatholobi had a greater anti-aggregating activity in PRP induced by ADP or PAF. Caulis Spatholobi and Flos Carthami showed significant inhibitory effects on the expression of P-selectin. CONCLUSIONS: Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae have potent anti-platelet properties, and their inhibitory actions are mediated via different mechanisms. Caulis Spatholobi inhibited ADP-induced platelet aggregation but not by thrombin, indicating that its mechanism of action might be independent of the thromboxane pathway. The effect of Caulis Spatholobi and Flos Carthami were associated with suppressing the expression of P-selectin.

Xanthatin induces G2/M cell cycle arrest and apoptosis in human gastric carcinoma MKN-45 cells.

Xanthatin, a natural bioactive compound of sesquiterpene lactones, was isolated and purified from air-dried aerial part of Xanthium sibiricum Patrin ex Widder. In the present study, we demonstrated the significant antiproliferative and proapoptotic effects of xanthatin on human gastric carcinoma MKN-45 cells. MTS assay showed that xanthatin produced obvious cytotoxicity in MKN-45 cells with IC50 values of 18.6, 9.3, and 3.9 µM for 12, 24, and 48 h, respectively. Results of flow cytometry analysis indicated that the antiproliferative activity induced by xanthatin might be executed via G2/M cell cycle arrest and proapoptosis in MKN-45 cells. Western blot analysis elucidated that: a) xanthatin downregulated expression of Chk1 and Chk2 and phosphorylation of CDC2, which are known as key G2/M transition regulators; b) xanthatin increased p53 activation, decreased the bcl-2/bax ratio and the levels of downstream procaspase-9 and procaspase-3, which are key regulators in the intrinsic apoptosis pathway; c) xanthatin blocked phosphorylation of NF-κB (p65 subunit) and of IκBα, which might contribute to its proapoptotic effects on MKN-45 cells. In conclusion, our results suggest that xanthatin may have therapeutic potential against human gastric carcinoma.