J Pharm Pharmacol 2014 Sep 6;66(9):1282-93. Epub 2014 Jun 6.
Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, Naresuan University, Phitsanulok, Thailand.
Objectives: Curcuma aeruginosa Roxb. extract is a 5α-reductase antagonist that can be used to treat hair loss. We aimed to study the stability of antiandrogenic constituents, germacrone and other sesquiterpene components in the extract.
Methods: Germacrone and the extract were analyzed as solid forms or solublized with polyethylene glycol-40 (PEG-40) or methanol using high-performance liquid chromatography and gas chromatography with flame ionization detector. The effects of pH, temperature and light on their stability were studied.
Key Findings: Degradation of antiandrogenic compounds in C. aeruginosa was highly sensitive to temperature especially pure anhydrous germacrone, which was completely lost within 3 days at 45°C. Curiously, degradation was slower than as a dried extract. Paradoxically, when solubilized with PEG-40, it was largely intact even after 90 days at 45°C. The MS spectrum of a major degradation product suggested that it was elemenone probably produced by Cope rearrangement. Two other putative degradation products were germacrone-1,10-epoxide and germacrone-4,5-epoxide suggesting that oxidation of double bonds was an important mechanism. Germacrone stability was unaffected by pH (2.0-9.0) but only as dried extract it was slightly degraded by light.
Conclusion: Antiandrogenic constituents of C. aeruginosa were instable at high temperature and in solid form. Thus, the extract would be optimately stored as a solution or otherwise as solid form at low temperature.