Risk assessment of plant food supplements and other herbal products containing aristolochic acids using the margin of exposure (MOE) approach

Figures & data

Figure 1. Structural formula of aristolochic acids (AAs).

Table 1. Product description of the PFS analysed in the present study.

Sample number	Product	Product presentation	Dosage	Suspected botanical ingredient	Country of origin
S1	Slimonil men	Capsule	1–2 capsules, 2 times per day	Aristolochia indica	India
S2	Marul Lupului-Antiinflamator	Plant leaf	1 teaspoon per day	Aristolochia clematitis	Romania
S3	Zhu Po Hou Zao San	Globule	0.45–0.6 g, 2–3 times per day	Asarum heterotropoides	China
S4	Aristolochia clematitis C100	Globule	5–30 globules per day	Aristolochia clematitis	Germany
S5	Ba Zheng San	Capsule	3–6 capsules, 3 times per day	Aristolochia (Guan Mu Tong)	China
S6	Long Dan Xie Gan Wan	Globule	0.5–1 pack, 2 times per day	Aristolochia manshuriens	China
S7	Jingzhi Kesou Tanchuan Wan	Capsule	1 capsule, 2 times per day	Aristolochia; xinxin	China
S8	Slimonil Women	Capsule	1–2 capsules, 2 times per day	Aristolocia indica	India
S9	Lotiune Marul Lupului	Tincture	1 teaspoon, 3 times per day	Aristolochia clematitis	Romania
S10	Fang Ji Huang Qi Tang	Capsule	3–6 capsules, 3 times per day	Stephania root (Han Fangji)	USA
S11	Varanadi Kwatham	Tablet	3 tablets, 2 times per day	Aristolochia bracteolate	India
S12	Yangxue Qingnao Keli	Globule	1 pack, 3 times per day	Xi Xin	China
S13	DaHuang	Plant stem	No information provided	Da Huang	China
S14	Zhengtian Wan	Globule	1 pack, 2–3 times per day	Xi Xin	China
S15	Fangxieye	Plant leaf	3–6 g per day	Folium Sennae	China
S16	Tong Cao	Plant stem	No information provided	Aristolochia; Xi Xin	China
S17	Akabea Moist Heat	Tablet	3 tablets, 3–4 times per day	Akabea trifoliate caulis (Mu Tong)	USA
S18	Aristolochia clematitis D12	Tablet	1 tablet per day	Aristolochia clematitis	Germany

Figure 2. Total number of plant food supplements and other herbal products containing AAs (a) and percentage of positive samples (means ± SD) (b) over the years. The details of each study are presented in the supplemental data online.

Table 2. Levels of aristolochic acid I (AAI) and aristolochic acid II (AAII) in positive samples of PFS (n = 3 independent analyses).

Sample number	Aristolochic acids (µg g^–1)
	AAI	AAII
S2	594.8 ± 126.7	235.3 ± 57.0
S4	2.1 ± 0.4	0.6 ± 0.0
S9	14.4 ± 0.8	5.7 ± 0.2

Figure 3. UPLC chromatogram of the methanol extract of sample S2 (declared to contain Aristolochia clematitis). Peaks marked with an asterisk (*) were not identified. The chromatogram was obtained at a wavelength of 240 nm.

Table 3. Estimated daily intakes (EDIs) of AAs.

Sample number	Recommended daily intake (g) of the PFS	EDI (µg kg^–1 bw day^–1)^a
S2	2.5	30
S4	0.04–0.25	1.7–11 × 10^–3
S9	4.5	1.3

Note: ^aEDI of AAI + EDI of AAII.

Table 4. Results from a BMD analysis of the data for kidney tumour formation in rats (Mengs et al. 1982) exposed to AAs using BMDS software version 2.5, a BMD of 10% and default settings based on assumption of equal potency of AAs.

Model	Restriction	Number of parameters	Log-likelihood	p-value	Accepted^a	BMD10 (µg kg^–1 body wt day^–1)	BMDL10 (µg kg^–1 body wt day^–1)
Reduced		1	–22.2921	–	–	–	–
Full		4	–15.5048	–	–	–	–
Gamma	None	4	–15.6056	0.9042	No	60	3
Logistic	n.a.^b	2	–16.3038	0.5144	Yes	150	100
LogLogistic	None	2	–15.5861	0.9528	No	50	4
LogProbit	None	2	–15.5422	0.9781	No	50	5
Multistage	None	2	–15.6008	0.9499	Yes	50	10
Probit	n.a.^b	2	–16.2417	0.9888	Yes	130	90
Weibull	None	2	–15.6055	0.5387	No	50	3
Quantal-Linear	n.a.^b	1	–15.6056	0.9409	Yes	50	30

Notes: ^aCriteria for acceptance included p >0.05 and the ratio between BMD₁₀ and BMDL₁₀ < 10.

^bNot applicable.

Table 5. MOE values of AAs resulting from the consumption of PFS.

Sample number	MOE
S2	0.3
S4	900–5800
S9	8

Figure 4. Number of samples with respective MOE values assuming a lifetime or 2 weeks of exposure to AAs based on samples analysed in the present study and reported in the literature. The MOE was calculated by dividing the lowest BMDL₁₀ of AAs of 10 µg kg^–1 bw day^–1 for kidney tumour formation by the EDI of AAs from the PFS and other herbal products.

Table 6. DNA adduct formation in the kidney of rats exposed to either AAI, AAII or a mixture of AAs obtained from the literature.

AA	Dose (mg kg^–1 bw day^–1)	Total number of adducts/10^8 nts^b	Slope of the curve for DNA adduct formation versus dose^c	Reference
AAI	0, 2.5, 15^a	0, 0.09, 0.4	0.03	Chan et al. (2008)
AAII		0, 0.16, 0.62	0.04
AAI	0, 0.04, 0.4, 4^a	0, 44.8, 320, 2588	641.3	Mei et al. (2006)
AAII	0, 0.056,0.56, 5.6^a	0, 49.1, 348.6, 2010	348.7	Mei et al. (2006)
AAI	0, 5	0, 984	196.8
AAII		0, 4180	836.0
AAI	0, 10	0, 42	4.2	Pfau et al. (1990)
AAII		0, 80	8.0

Notes: ^aAdjusted dose = dose × percentage of AAI or AAII.

^bTotal number of adducts presented was based on the total number of deoxyadenosine and deoxyguanosine adducts formed upon exposure to AAI or AAII.

^cSlope was calculated using the reported DNA adduct level at each tested dose level and assuming zero adduct formation at zero dose.

Mengs U, Lang W, Poch J-A. 1982. The carcinogenic action of aristolochic acid in rats. Arch Toxicol. 51:107–119.

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Chan W, Yue H, Poon WT, Chan Y-W, Schmitz OJ, Kwong DW, Wong RN, Cai Z. 2008. Quantification of aristolochic acid-derived DNA adducts in rat kidney and liver by using liquid chromatography–electrospray ionization mass spectrometry. Mutat Res/Fund Mol Mech Muta. 646:17–24.

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