Detection of Volatile Metabolites Derived from Garlic (Allium sativum) in Human Urine

Abstract

Abstract:The metabolism and excretion of flavor constituents of garlic, a common plant used in flavoring foods and attributed with several health benefits, in humans is not fully understood. Likewise, the physiologically active principles of garlic have not been fully clarified to date. It is possible that not only the parent compounds present in garlic but also its metabolites are responsible for the specific physiological properties of garlic, including its influence on the characteristic body odor signature of humans after garlic consumption. Accordingly, the aim of this study was to investigate potential garlic-derived metabolites in human urine. To this aim, 14 sets of urine samples were obtained from 12 volunteers, whereby each set comprised one sample that was collected prior to consumption of food-relevant concentrations of garlic, followed by five to eight subsequent samples after garlic consumption that covered a time interval of up to 26 h. The samples were analyzed chemo-analytically using gas chromatography-mass spectrometry/olfactometry (GC-MS/O), as well as sensorially by a trained human panel. The analyses revealed three different garlic-derived metabolites in urine, namely allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO) and allyl methyl sulfone (AMSO 2 ), confirming our previous findings on human milk metabolite composition. The excretion rates of these metabolites into urine were strongly time-dependent with distinct inter-individual differences. These findings indicate that the volatile odorant fraction of garlic is heavily biotransformed in humans, opening up a window into substance circulation within the human body with potential wider ramifications in view of physiological effects of this aromatic plant that is appreciated by humans in their daily diet.

Identification and Quantification of Volatile Ramson-Derived Metabolites in Humans

“…DADS, are transformed to allyl mercaptan which is subsequently methylated to AMS (Germain et al, 2002 ; Lawson and Wang, 2005 ). The formation of AMS after garlic consumption was previously confirmed by our group (Scheffler et al, 2016a , b ). Now, we can also confirm the presence of AMS in human milk and urine after ramson consumption.…”

“…In most cases, irrespective of the consumed amount of ramson and the investigated excretion product, AMS, AMSO, and AMSO 2 , were only detected in samples after ramson consumption, demonstrating that they clearly derived from ramson consumption. In previous studies we were able to identify the same metabolites in urine and milk samples obtained after garlic consumption (Scheffler et al, 2016a , b ). It can be assumed that AMS, AMSO, and AMSO 2 are not ramson-specific metabolites but may be rather linked to several sulfur constituents-bearing foods.…”

“…Confirmation/ identification or exclusion of the compounds was conducted by means of HRGC-GC-MS. M 2-2 (2.4 h after ramson consumption) and U 1-4 (2 h after ramson consumption) are displayed as representative examples of data obtained for the samples provided after ramson consumption . a (Yu et al, 1989 ), b (Mazza et al, 1992 ), c (Mondy et al, 2001 ), d (Lee et al, 2003 ), e (Abu-Lafi et al, 2004 ), f (Calvo-Gómez et al, 2004 ), g (Kimbaris et al, 2006 ), h (Sobolewska et al, 2013 ), i (Tokarska and Karwowska, 1983 ), j (Galoburda et al, 2013 ), k (Schmitt et al, 2005 ), l (Godevac et al, 2008 ), m (Radulović et al, 2015 ), n (Blazewicz-Wozniak and Michowska, 2011 ), o (Cai et al, 1995 ), p (Hansanugrum and Barringer, 2010 ), q (Munch and Barringer, 2014 ), r (Suarez et al, 1999 ), s (Taucher et al, 1996 ), t (Buhr et al, 2009 ), u (Rosen et al, 2000 ), v (Lawson and Wang, 2005 ), w (Scheffler et al, 2016b ), x (Scheffler et al, 2016a ), y (Brady et al, 1991 ), n.d.: not detected .…”

“…The materials and methods that were used in this study are in most parts in line with those described in our previous studies which addressed the identification and quantification of garlic-derived metabolites in human milk and urine (Scheffler et al, 2016a , b ; Scheffler et al, submitted). For this reason only a short overview is provided here.…”

“…In case of garlic ingestion our group already identified three metabolites excreted via human milk and urine, namely allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO) and allyl methyl sulfone (AMSO 2 ) with only AMS present in garlic itself whereas the other two compounds are only formed within the human body (Scheffler et al, 2016a , b ). In case of ramson there is no data available concerning its metabolism within the human body.…”