The dynamic distribution patterns and lung targeting efficiency in rats of 9 bioactive components in Siraitia...

Siraitia grosvenorii (S. grosvenorii) is a traditional herbal medicine employed for the prevention of lung diseases. Mogrosides and flavonoids are postulated to be the principal active components. Nevertheless, the dynamic distribution of its active components in vivo and the amount of accumulation in the lung target tissue remain indistinct.

This study investigates the dynamic distribution patterns of 9 bioactive components within the extract of S. grosvenorii in rat blood, heart, liver, spleen, lung, and kidney, along with its pulmonary targeting.

The blood, heart, liver, spleen, lung, and kidney samples of rats were obtained at diverse time points after oral administration of S. grosvenorii decotion, and a UPLC-MS/MS method was developed to determine the contents of 9 bioactive components (Siamenoside I, Grosvenorine, 11-O-Mogroside V, Mogroside II-E, Mogroside III-E, Mogroside IV-A, Mogroside V, Mogroside VI and Kaempferitrin) within the samples. The concentration-time curves of each component in each sample were plotted and the pharmacokinetic parameters were computed.

The AUC_0→∞ and C_max of 9 bioactive components in lung tissue were conspicuously higher than those in heart, liver, spleen, and kidney. For instance, the AUC_0→∞ of Mogroside V in lung tissue was 7.20-55.54 times higher than that in blood and other tissues, and the C_max in lung tissue was 3.315-96.70 times higher than that in blood and other tissues. The lung target efficiency of 9 bioactive components ranged from 1.885 to 15.80, indicating that the active components of S. grosvenorii exerting pharmacological effects are highly concentrated in the lung target tissue. The T_max of 9 bioactive components in blood was within the range of 10.20-100.2 min, while the T_max of the heart and liver was 20 min. The T_max of all the components in the lung was 50 min, while the T_max of the spleen and kidney was from 80 to 100 min, suggesting that 9 bioactive components entered the blood rapidly and then distributed to the heart and liver in large quantities, before entering the lung tissue in large quantities and eventually distributing to the spleen and kidney. The elimination half-life (T_1/2) of the majority of 9 bioactive components was less than 1 h, and the MRT of most of them was less than 3 h.

S. grosvenorii is a naturally lung-targeted herbal medicine, and the clinical administration ought to be based on pharmacokinetic parameters such as Tmax, Cmax, AUC_0→∞, T_1/2, and MET_0→∞ in lung tissue for designing a precise, rigorous, and rational administration plan.