Nutraceuticals & Shelf Stability: Monitoring Bioactive Compounds

With the burgeoning interest in plant-derived nutraceuticals, evaluating these products for stability is imperative. In particular, storage and temperature conditions can alter the concentration of bioactive compounds, leading to transformation products.

Toward this end, ultra high performance liquid chromatography high resolution mass spectrometry (UHPLC-HRMS) is a robust tool for monitoring bioactive compounds over time and identifying potential transformation products. Its ability to track an unlimited number of analytes in full-scan mode and also to perform retrospective analysis for compounds absent from the target list renders it ideal for this application.

López-Gutiérrez et al. (2016) recently harnessed a Transcend UHPLC system and an Orbitrap Exactive mass spectrometer (both Thermo Scientific) to monitor four commercial nutraceutical matrices- grape, tea, royal jelly, and soy- over one year of storage at 5°C.¹ The team focused on the detection of alterations in bioactive compounds as well as the emergence of new bioactive compounds arising as transformation products. They relied on Xcalibur and ToxID software (both Thermo Scientific) for instrument control, data analysis, and analyte screening.

The team found that most bioactive compounds remained constant while some decreased or increased in concentration when compared with the initial observations:

Matrix	Green Tea		Soy		Grapes	Royal Jelly
	T1	T2	S1	S2
Constant	apigenin-6- C-glucoside, apigenin-8-C-glucoside, biochanin A, gallic acid, kaempferol-3- O-glucoside, luteolin-40 -O-glucoside, luteolin-6-C-glucoside, quercetin-3- O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, quercetin-3- O-rutinoside	apigenin- 8-C-glucoside, (+)- catechin, gallic acid, kaempferol- 3-O-glucoside, kaempferol-3-Orutinoside, luteolin-40 -O-glucoside, luteolin-6- C-glucoside, luteolin-8-C-glucoside, quercetin-3-Ogalactoside, quercetin-3-O-glucoside, quercetin- 3-O-rutinoside	daidzein, daizin, ferulic acid, genistein, genistin,	daidzein, daidzin, glycitein, glycitin	caffeic acid, ()-epicatechin, ()- epicatechin gallate, genistein, kuromanin chloride, naringenin, resveratrol	acacetin, apigenin-6-C-glucoside, apigenin-7- O-glucoside, apigenin-8-C-glucoside, biochanin A, chrysin, daidzein, glycitein, isorhamnetin, kaempferol, luteolin-6-C-glucoside, quercetin-3- O-rutinoside, tamarixetin
Decrease	(+)-catechin, (-)-epicatechin, kaempferol-3- O-rutinoside, luteolin-8-C-glucoside	(-)- epicatechin	glycitein, glycitin, isosakuranetin, kaempferol-3-O-glucoside, luteolin, luteolin-40 – O-glucoside, naringenin, quercetin-3- O-rhamnoside, sakuranetin, sinapic acid	no compound	quercetin-3- O-galactoside, quercetin-3-Oglucoside	no compound
Increase	Acacetin, luteolin	Apigenin- 6-C-glucoside	no compound	genistein, genistin	(+)- catechin, quercetin	quercetin- 3-O-galactoside, quercetin-3-Oglucoside

Degradation products began to appear after three months of storage for green tea and soy products and after six months of storage for royal jelly:

	3 months	6 months	12 months
Green Tea	Coumestrol (2.2 ± 15.5) Formononetin (0.2 ± 9.7) Pinocembrin (0.3 ± 17.5)	Coumestrol (1.7 ± 6.7) Formononetin (2.1 ± 2.2) Pinocembrin (3.2 ± 12.9)	Coumestrol (8.4 ± 2.5) Pinocembrin (8.3 ± 0.6)
Soy	Formononetin (0.4 ± 5.5)		Coumestrol (12.3 ± 13.0)
Royal Jelly		Isorhamnetin (0.02 ± 0.01) Quercetin (2.1 ± 0.2) Quercetin-3-O-glucoside (0.2 ± 0.2)	Isorhamnetin (0.9 ± 6.5) Pinocembrin (0.1 ± 5.7) Quercetin-3-O-glucoside (0.4 ± 0.8)

Overall, López-Gutiérrez et al. indicate the critical requirement to use high resolution mass spectrometers capable of performing in full-scan mode when attempting to detect transformation products. In the application presented here, this technology in concert with an expansive database of bioactive compounds enabled the detection of alterations and degradation products over a full 12 months of storage at cool temperatures. This data is critical for understanding how storage impacts nutraceutical quality and efficacy.

For further discussion on nutraceutical analysis, visit our food and beverage learning center.

Reference

1 López-Gutiérrez, N. et al. (2016) ‘Influence of storage conditions in the evolution of phytochemicals in nutraceutical products applying high resolution mass spectrometry.’ Food Chemistry 201: 59–63.