Nepetifoliol - a new glutinane-triterpenoid from Leonotis nepetifolia.

A new glutinane-triterpenoid, nepetifoliol (1), together with two known compounds, dymacrin D (2), and (+)-ar-tumerone (3) were isolated from the n-hexane extract of the aerial parts of Leonotis nepetifolia. Their chemical structures were elucidated by spectroscopic data analysis as well as the comparison of their NMR data with the ones published in the literatures. A putative biosynthetic pathway for the formation of the new compound (anti-diaxial-5,6-diol) (1) from the precursor triterpene glutinol was proposed. Compounds (2), (3) and some previously reported ones, isolated from this extract, including 5α-stigmasta-22-ene-3-one (4), friedelin (5), chrysophanol (6), physcion (7), and 4'-O-methylalpinumisoflavone (8) were evaluated for their α-glucosidase inhibition. Among tested compounds, 3 and 6 showed good activities with their IC50 values of 5.3 ± 0.2 and 4.9 ± 0.3 µg/mL, respectively, comparing to the positive control, acarbose (IC50 127.7 ± 0.2 µg/mL).

Apply the accelerated stability test to predict the self-life of national standard serum tetanus antitoxin

Accelerated stability test has been applied for predicting self-life of national standard serum tetanus anti-toxin (SAT). Samples of the tetanus antitoxin were kept at - 20°C, 4°C, 22°C, 37°C and 45°C for 6 months and their potency was estimated by using the toxin neutralization method on mice. There was relationship between the potency change and the self- life of serum tetanus antitoxin by using Arrhenius equation. The results demonstrated that the self-life of the national standard serum tetanus antitoxin was 9 years and 6 months when stored at -20°C.