Anti-cancer activity of Conyza blinii saponin against cervical carcinoma through MAPK/TGF-β/Nrf2 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Conyza blinii H.Lév. is a type of natural plant distributed in southwest of China. Its dried overground section can be used in traditional Chinese medicine (TCM) for treating infections, inflammations and occasionally cancers. CBS (Conyza blinii saponin), mainly composed of triterpenoidal saponins of Conyza blinii H.Lév. CBS is considered as the major active fraction of this species. The current investigation have focused on the mechanisms of CBS with regard to its anti-cancer activity. Hence it is of high relevance of identifying the anti-cancer efficacy of ethnomedicine.

AIM OF THE STUDY

To understand the anti-cancer mechanism of CBS using both in vitro and in vivo experiments.

MATERIALS AND METHODS

CBS (Conyza blinii saponin) was obtained as described previously. We tested the anti-cancer activity of CBS using in vitro HeLa cell models and in vivo animal models. We adopted immunoblot, RT-PCR (reverse transcription polymerase chain reaction), luciferase reporter assay and flow cytometry to study relevant proteins, genes, pathways and cellular ROS (reactive oxygen species) responsible for anti-cancer activity of CBS. More, 24 tumour-xenografted mice were grouped randomly as 'control', 'cisplatin' (as positive control), 'low dose' and 'high dose' groups. The IL-1β, TNF-α, PGE2 and IL-2 in the blood serum and the tumour tissue of mice were measured.

RESULTS AND CONCLUSIONS

We have found that CBS is capable of inducing apoptotic cancer cell death via both caspase-dependent and -independent pathways. CBS inhibits the activation of TGF-β signaling pathway in a dose- and time-dependent manner. Phospho-ERK, phospho-JNK and phospho-p38 MAPK are significantly suppressed by CBS. Furthermore, some inflammation mediators including IL-1β, TNF-α and PGE2 from animal samples were found decreased in CBS-treated mice models. In contrast, the level of IL-2, a cytokine commonly used for treating cancers, increased reversely. Last, we have discovered that CBS is able to decrease the expression of Nrf2, inhibit the activation of ARE and increase ROS level in HeLa cells. In summary, we have confirmed that the anti-cancer activity of CBS is possibly related to its TGF-β, MAPK, Nrf2 signaling pathways as well as some cancer related inflammation mediators and cytokines.

The protective activity of Conyza blinii saponin against acute gastric ulcer induced by ethanol

ETHNOPHARMACOLOGICAL RELEVANCE

Conyza blinii H.Lév., is a type of natural plant. Its dried overground section is used to treat infections and inflammations in traditional Chinese medicine. Triterpenoidal saponins have a wide range of bioactivities, for instance, anti-cancer, anti-virus and anti-anaphylaxis. Conyza blinii saponin (CBS), mainly composed of triterpenoidal saponins, is the total saponin of Conyza blinii H.Lév. It has been reported that CBS also has gastric mucous membrane protection activity. This study aims to test CBS׳s protective activity of gastric׳s mucous membrane against ethanol. This investigation may lead to the development of novel drug from natural products as anti-ulcer agent, or as gastric mucous protective against chemical damage.

MATERIALS AND METHODS

CBS (Conyza blinii saponin) is the total saponin of Conyza blinii H.Lév., which was obtained as described previously. We tested the protective activity of CBS against ethanol-induced ulcer. Thirty six rats were grouped randomly as 'NORMAL', 'CONTROL', 'MODEL', 'LOW DOSE', 'MEDIUM DOSE' and 'HIGH DOSE'. The 'NORMAL' group were rats with no pathological model established within it. The 'CONTROL' group was administrated with colloidal bismuth subcitrate, while 'MODEL' group was not given any active agents apart from absolute ethanol in order to obtain gastric ulcer model. The three 'DOSE' groups were treated with different concentrations of CBS (5, 10, 20mg/mL) before administration followed by absolute ethanol. All rats were sacrificed after the experiment to acquire the gastric tissue. The ulcer index (UI), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured to monitor the activity of CBS. Besides, the rat gastric tissue was made to paraffin section and stained using the Hematoxylin-Eosin (HE) method. The histopathology examination was carried out to examine CBS efficacy in terms of gastric mucous protection.

RESULTS

We found that CBS had a profound protection activity against acute gastric ulcer induced by ethanol and this activity displayed a concentration-dependent manner. The efficacy of 10 and 20mg/mL CBS was comparable with colloidal bismuth subcitrate (P<0.05). All three level of CBS tested were able to significantly reduce UI, MDA and enhance SOD level (P<0.05).

CONCLUSIONS

It was deduced that the mechanism for such activity would be anti-lipid peroxidation, facilitating free radicals clearance. In addition , histopathology examination of the gastric mucous membrane supported the same conclusion, that CBS can efficiently suppress the inflammatory reactions, bleeding and protect the gastric mucosa.