Stability studies of antiandrogenic compounds in Curcuma aeruginosa Roxb. extract Nungruthai Suphrom a , Jukkarin Srivilai a , Ganniga Pumthong b , Nantaka Khorana c , Neti Waranuch b , Nanteetip Limpeanchob d and Kornkanok Ingkaninan a a Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, b Department of Pharmaceutical Technology, c Department of Pharmaceutical Chemistry and Pharmacognosy, d Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand Keywords antiandrogen; Curcuma aeruginosa; degradation; germacrone; stability Correspondence Kornkanok Ingkaninan, Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand. E-mail: k_ingkaninan@yahoo.com Received June 28, 2013 Accepted December 7, 2013 doi: 10.1111/jphp.12216 Abstract 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 impor- tant 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. Introduction Curcuma aeruginosa Roxb. (Zingiberaceae) is a native plant of tropical areas and is commonly known as Wanmahamek in Thailand. It is a perennial with oblong tuberous roots, and the fresh rhizome emits a ginger-like aroma. Leafy shoots are 45–60 cm high and the plant blooms during the rainy season. [1–3] In Thai traditional medicine, a tincture of the rhizome is used to treat uterine pain, uterine inflamma- tion, postpartum uterine and perimenopausal bleeding. [4] Various pharmacological effects of this plant have been delineated such as postcoital contraception, anti-HIV actions, hepatoprotection, antimicrobial effects, antioxi- dation, reduce platelet activation and antinociception. [1,5–7] Recently, our group found that a hexane extract of C. aeruginosa rhizomes showed high antiandrogenic activity both in vitro and in vivo. It was shown to be an effective ingredient in a hair tonic for androgenic alopecia. [8] Six sesquiterpenes, that is, germacrone, zederone, dehydrocur- dione, curcumenol, zedoarondiol and isocurcumenol were isolated from C. aeruginosa extract (Figure 1), and these were shown to inhibit the conversion of testosterone to dihydrotestosterone. Of the six components, germacrone was the most active. Our studies demonstrated that germacrone also showed an antiandrogenic action on testosterone-induced growth suppression of human pros- tate cancer cells [Lymph Node Carcinoma of the prostate (LNCaP)] and on the hamster flank gland model. A possible mechanisms was blockade of 5α-reductase activity whereas no binding of germacrone to androgen receptors could be detected. [9] Thus, germacrone has potential applications in the treatment of androgen-dependent disorders. But its success as a cosmetic or health product depends on its chemical stability. Therefore, the present study was And Pharmacology Journal of Pharmacy Research Paper © 2014 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology, 66, pp. 1282–1293 1282 Downloaded from https://academic.oup.com/jpp/article/66/9/1282/6128009 by guest on 26 July 2022