Inactivation of jack bean urease by scutellarin: elucidation of inhibitory efficacy, kinetics and mechanism.

In the present study, the inactivation effect of scutellarin (SL) on jack bean urease was investigated to elucidate the inhibitory potency, kinetics and mechanism of inhibition. It was revealed that SL acted as a concentration- and time-dependent inactivator of urease characteristic of slow-binding inhibition with an IC50 of 1.35±0.15 mM. The rapid formation of the initial SL-urease complex with an inhibition constant of Ki=5.37×10(-2) mM was followed by a slow isomerization into the final complex with the overall inhibition constant of Ki*=3.49×10(-3) mM. High effectiveness of thiol protectors, such as L-cysteine (L-cys), 2-mercaptoethanol (2-ME) and dithiothreitol (DTT) significantly slowed down the rate of inactivation, indicating the strategic role of the active site sulfhydryl group in the blocking process. While the insignificant protection by boric acid and fluoride from the inactivation further confirmed that the active site cysteine should be obligatory for urease inhibition, which was also rationalized by the molecular docking study. The inhibition of SL on urease proved to be reversible since SL-blocked urease could be reactivated by DTT application and multidilution. The results obtained indicated that urease inactivation resulted from the reaction between SL and the sulfhydryl group.

Anti-Candida albicans activity and pharmacokinetics of pogostone isolated from Pogostemonis Herba.

The present work was designed to evaluate the in vitro and in vivo anti-Candida activity of pogostone (PO), a natural product isolated from Pogostemon cablin (Blanco) Benth. PO showed potent in vitro activity against clinical Candida spp. isolates tested in this study. PO and the reference drug voriconazole (VRC) were equally effective against all the fluconazole-resistant Candida albicans strains, with MIC ranging from 3.1 µg/ml to 50 µg/ml. Besides, PO was fungicidal against all Candida isolates with MFC ranging from 50 µg/ml to 400 µg/ml. By contrast, VRC was fungistatic as it failed to elicit a fungicidal effect against the Candida spp. isolates at the highest tested concentration (400 µg/ml). Furthermore, oral and topical PO administration effectively reduced the fungal load in vagina of vulvovaginal candidiasis mouse models. Topical PO administration (1.0-4.0 mg/kg) demonstrated higher activity against the vulvovaginal candidiasis than VRC (4.0 mg/kg). The pharmacokinetics and safety profile of PO were also investigated. The pharmacokinetics assay revealed that PO was easily absorbed after oral administration in mice, which might account for its in vivo anti-Candida effect. The acute toxicity test showed that the median lethal dose of PO in mice was 355 mg/kg, which was much higher than the daily dose used for the therapeutic experiments. This study demonstrated the potential of PO as a promising candidate for the treatment of Candida infections, particularly for vulvovaginal candidiasis.

Experimental study on anti-inflammatory activity of a TCM recipe consisting of the supercritical fluid CO2 extract of Chrysanthemum indicum, Patchouli Oil and Zedoary Turmeric Oil in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Chrysanthemum indicum (Compositae) Linné, Pogostemon cablin (Blanco) Benth and Curcuma wenyujin (Zingiberaceae) Y. H. Chen et C. Ling are three of the extensively used herbal remedies among traditional Chinese medicines for the purpose of anti-inflammation. A traditional Chinese medicine (TCM) recipe named CPZ consisting extracts of the above three herbs, has shown noteworthy anti-influenza activity, which is closely related to its anti-inflammatory feature. AIM OF THIS STUDY: To investigated the anti-inflammtory activity of CPZ in vivo for a further exploration of the recipe's anti-inflammatory properties. MATERIALS AND METHODS: The anti-inflammatory property of CPZ on acute inflammation was evaluated by inflammatory models of dimethylbenzene (DMB)-induced ear vasodilatation and acetic acid-induced capillary permeability enhancement in mice, as well as the carrageenan-induced paw edema rat model, in which inflammation-related cytokine including prostaglandin E(2) (PGE(2)), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and nitric oxide (NO) in the edematous paw tissue were determined by enzyme linked immunosorbent assay (ELISA). Moreover, effect of CPZ on chronic inflammation was observed through granuloma formation in rats subjected to cotton pellet implantation. RESULTS: CPZ (340, 170, and 85 mg/kg for mice, p.o.) not only decreased the DMB-induced ear vasodilatation but also attenuated capillary permeability under acetic acid challenge in mice. And the significant inhibition on carrageenan-induced paw edema was observed. Further more, the ELISA results showed that CPZ (170, 85, and 42.5 mg/kg for rats, p.o.) could up-regulate the level of IL-1ß in the edema paw tissue of rats significantly while down-regulate that of PGE(2), but no apparent effect on TNF-α or NO was observed in the test. Besides, CPZ had a certain degree of restraining effect on the cotton pellet-induced granuloma formation in rats and the highest dose of 170 mg/kg even showed a significant suppression on it. CONCLUSION: The above results indicated that CPZ possessed a potent anti-inflammatory activity, which is indicated to be closely associated with its regulation on IL-1ß and PGE(2) thereby mediating the inflammatory response acting at an appropriate level.