The tranquillizing effects of
quercetin on allergic
asthma are promising, but its poor water solubility and bioavailability is still a bottleneck. In this study, an
ovalbumin (OVA) sensitized BALB/c mice
asthma model was used to investigate the potential of
quercetin nanocrystals (nQ) on relieving
asthma aggravation. The water soluble nQ was prepared by the homogenization using the high energy sonication method. X-ray diffraction data showed the formation of nQ (10-30 nm) which was in agreement with transmission electron microscopy. The nQ was found to be more stable and soluble in PBS, and sera of BALB/c mice compared to bulk
quercetin. Dose dependent experiments with nQ on OVA sensitized
asthma mice exhibited significant
anti-asthmatic potential of nQ at much lower dose (1 mg/kg
body weight) compared to bulk
quercetin. The treatment of nQ remarkably resulted in reduced OVA specific
immunoglobulin E (sIgE) production,
anaphylaxis signs and type 1 skin test. The nQ also significantly modulated the expression of Th2
cytokines like
IL-4 and
IL-5, which are responsible for
IgE class switching and suppressed the degranulation/secretion of different chemical mediators (
PGD2, mMCPT-1 Cys-L and TSLP) from activated mast cells. The levels of FcεR1, Syk, c-Yes, PI-3, p-PI-3, PLC-γ2, and p-PLC-γ2 were found to be reduced in the OVA sensitized BALB/c mice treated with nQ compared to those treated with OVA only. The results indicate that nQ alleviate
pulmonary inflammation and airway hyporesponsiveness in allergic
asthma at much lower dose compared to bulk
quercetin and may be considered as a potential drug for the treatment of asthmatic patients.