2019 Volume 67 Issue 6 Pages 527-533
In this study, we aimed to evaluate the quality of 11 products sold in Japan (one medicinal product and 10 dietary supplements) containing/claiming to contain chasteberry extract (fruit of Vitex agnus-castus L.) using HPLC fingerprint (15 characteristic peaks), quantitative determination of chemical marker compounds, and a disintegration test. The HPLC profile of the medicinal product was similar to that of the reference standard of V. agnus-castus fruit dry extract obtained from European Directive for the Quality of Medicines (EDQM), whereas the profiles of some dietary supplements showed great variability, such as different proportions of peaks or lack of peaks. Results of the principal component analysis of the fingerprint data were consistent with those of the HPLC profile analysis. The contents of two markers, agnuside and casticin, in dietary supplements showed wide variability; this result was similar to that achieved with the HPLC fingerprint. In particular, agnuside and/or casticin was not detected in two dietary supplements. Furthermore, one dietary supplement was suspected to be contaminated with V. negundo, as evidenced from the results of agnuside to casticin ratio and assay of negundoside, a characteristic marker of V. negundo. Results of the disintegration test showed poor formulation quality of two dietary supplements. These results call attention to the quality problems of many dietary supplements, such as incorrect or poor-quality origin, different contents of the active ingredient, and/or unauthorized manufacturing procedures.
Many dietary supplements containing herbs or herbal extracts have been introduced into the Japanese market to meet the requirements of the increasing number of health-conscious consumers. However, concerns have been raised about the quality and safety of some products.1,2) For instance, unexpected adverse effects by the dietary supplements were reported due to the poor quality of materials or overdose intake.3–5) Furthermore, some of the dietary supplements distributed in Japan contain inappropriate materials or amounts other than those included in the label.6–9) Following the situation, we consider that it is important to provide quality information of dietary supplement.
Chaste tree (Vitex agnus-cactus L.) is a deciduous shrub or small tree, native to Mediterranean Europe, Central Asia, and part of India. Its fruit, chasteberry, has been topically used for treatment of pain, swelling, and inflammation, as well as relief of headaches, joint pain, rheumatism, and reproductive pain in ancient Europe.10) Since the mid-20th century, chasteberry has been widely used for treatment of gynecological conditions, such as premenstrual syndrome (PMS), cyclic mastalgia, and menstrual irregularities.11) Recently, placebo-controlled, double-blind clinical trials of a medicinal product containing chasteberry extract showed its safety and efficacy in patients with PMS.12,13) In Europe, chasteberry extracts have been widely incorporated in medicinal products, whose quality complies with the requirements of the European pharmacopoeia to guarantee their safety and efficacy.14,15) In addition, a clinical study showed the safety and efficacy of chasteberry extract in Japanese patients with PMS,16) and a medicinal product containing chasteberry extract (Prefemin®) was launched into the Japanese market in 2014. Since then, several dietary supplements containing chasteberry or its extract have been distributed again in the Japanese market. Our previous study using HPLC fingerprint and assay of analytical markers revealed that some dietary supplements contained incorrect Vitex species despite the label claim of chasteberry or its extract content.17) Therefore, this raised a major concern about the safety and efficacy of dietary supplements.
In the present study, we further assessed the quality of dietary supplements containing chasteberry extract, which are currently sold in Japan, using principal component analysis (PCA) analysis and disintegration test in addition to our previously reported methods, HPLC fingerprint and assay of analytical markers, and compared with the medicinal product.
HPLC-grade methanol, analytical grade phosphoric acid, and potassium phosphate monobasic were purchased from Kanto Chemical Co., Inc. (Tokyo, Japan). Distilled deionized water was obtained using a Millipore ultrapure water system (Millipore, Bedford, MA, U.S.A.). p-Hydroxybenzoic acid (PHBA, Kanto Chemical Co., Inc.), homoorientin (ChromaDex, Irvine, CA, U.S.A.), agnuside (Phytoplan Diehm & Neuberger, Heidelberg, Germany), casticin (Phytoplan Diehm & Neuberger), and negundoside (Phytolab GmbH & Co., KG, Vestenbergsgreuth, Germany) were used. V. agnus-castus fruit dry extract (reference standard) was purchased from European Directive for the Quality of Medicines (EDQM, Strasbourg, France). One medicinal product and ten dietary supplements were used as test samples (Table 1). The medicinal product was developed in Japan, and all dietary supplements were purchased through online shopping sites in Japan from October till November, 2016. V. negundo L. leaves collected from Guangxi and Guizhou region were purchased at local Chinese market and deposited in Zeria Pharmaceutical Co., Ltd., Japan.
| Sample | Category | Daily dosage and forma,b) |
|---|---|---|
| A | Medicinal product | 20 mg extract in 1 coated tablet |
| B | Dietary supplement | 40 mg extract in 2 hard capsules |
| C | Dietary supplement | Extract (40 mg chasteberryc)) in 3 g granule |
| D | Dietary supplement | Extract (40 mg chasteberryc)) in 1 hard capsule |
| E | Dietary supplement | 42 mg extract in 2 plain tablets |
| F | Dietary supplement | Extract in 2 plain tablets |
| G | Dietary supplement | Chasteberry in 3 coated tablets |
| H | Dietary supplement | Extract (40 mg chasteberryc)) in 2 plain tablets |
| I | Dietary supplement | 20 mg extract in 1 hard capsule |
| J | Dietary supplement | Extract (40 mg chasteberry) in 1 soft capsule |
| K | Dietary supplement | More than 40 mg extractc) in 2 hard capsules |
a) Other ingredients are included in all dietary supplements. b) The recommended daily dosage in the labels are listed. c) Official website information.
An HPLC system (Waters, Milford, MA, U.S.A.), consisting of separation module 2695, photodiode array (PDA) detector 2998 and Empower 3 data processing equipment, was used to perform the HPLC analysis. Samples for quantitative determination were analyzed twice and average values were stated.
HPLC FingerprintingHPLC fingerprinting was carried out as previously reported.17) Chemical marker compounds (PHBA, homoorientin, agnuside, and casticin; 5 mg) were weighed and dissolved in 80% methanol in a 5-mL volumetric flask. Two milliliters of this solution were accurately diluted to 50 mL with 80% methanol as a standard solution. The reference standard of V. agnus-castus fruit dry extract (20 mg) was weighed, placed in 15-mL centrifuge tube, and 5 mL of 80% methanol was added. The tube was vigorously shaken and centrifuged at 3000 rpm for 5 min. The supernatant was then filtered through a 0.45-µm polyvinylidene difluoride (PVDF) membrane filter before use. Powdered tablets and the contents of capsules or granules (daily dosage or recommended minimum daily intake) were weighed and mixed with 5 mL of 80% methanol. After vigorous shaking, the samples were centrifuged at 3000 rpm for 5 min. The supernatants were filtered through a 0.45-µm PVDF membrane filter before use. HPLC analysis was carried out on a Symmetry C18 column (100 × 4.6 mm, 3.5 µm, Waters) at 35°C with a sample injection volume of 10 µL. The mobile phase consisted of methanol (A) and 5 mL/L phosphoric acid aqueous solution (B), using a gradient elution program, as follows: 0 min, 5% A; 3 min, 10% A; 7 min, 15% A; 19 min, 25% A; 25 min, 27% A; 30 min, 30% A; 39 min, 34% A; 44 min, 37% A; 49 min, 50% A; and 75 min, 90% A. The flow rate was 1 mL/min. UV spectra were recorded between 210 and 450 nm, and HPLC chromatograms were plotted at 275 nm. Peak areas were determined by the automatic integration method. The typical 15 peaks obtained from the reference standard were selected for the analysis. Each peak obtained from the test samples was identified by comparing its relative retention time and UV spectrum with those of the reference standard.
PCA of samples A–K was performed using R software.18) Fifteen characteristic peaks were selected in this analysis.
Quantitative Determination of CasticinQuantitative determination of casticin was carried out in accordance with the United States Pharmacopeia (USP) 40 and the National Formulary (NF) 35, Powdered Chaste Tree Extract.19) Casticin (5 mg) was weighed and dissolved in methanol in a 100-mL volumetric flask with sonication and then filtered through a 0.45-µm cellulose acetate membrane filter. The concentration of casticin in the standard solution was 0.05 mg/mL. The reference standard (20 mg) was weighed, placed in a 50-mL volumetric flask, and extracted with 25 mL of methanol at 40°C for 10 min by sonication. The solution was adjusted to 50 mL with methanol and then filtered through a 0.45-µm PVDF membrane filter. Powdered tablets and the contents of capsules or granules (daily dosage or recommended minimum daily intake) were weighed and extracted as previously mentioned. HPLC analysis was carried out on a HYPERSIL BDS-5C18 column (125 × 3 mm, 5 µm, ChemcoPak) at 25°C with a sample injection volume of 10 µL. The mobile phase consisted of methanol (A) and 3.48 mL/L phosphoric acid aqueous solution (B), using a gradient elution program: 0 min, 50% A; 13 min, 65% A; 18 min, 100% A; 23 min, 50% A. The flow rate was 1 mL/min, and the optimized detection wavelength was 348 nm. The quantitation limit of this analysis was approximately 0.15 µg/mL.
Quantitative Determination of AgnusideQuantitative determination of agnuside was carried out in accordance with the USP40 and NF35, Powdered Chaste Tree Extract.19) Agnuside (5 mg) was weighed and dissolved in 5% methanol in 50-mL volumetric flask with sonication. Two milliliters of this solution were diluted to 50 mL and filtered through a 0.45-µm PVDF membrane filter. The concentration of agnuside in the standard solution was 0.04 mg/mL. Sample solutions were prepared as previously mentioned in the quantitative determination of casticin. HPLC analysis was carried out on a HYPERSIL BDS-5C18 column (125 × 3 mm, 5 µm, ChemcoPak) at 25°C with a sample injection volume of 10 µL. The mobile phase consisted of acetonitrile (A) and 3.48 mL/L phosphoric acid aqueous solution (B), using a gradient elution program: 0 min; 7% A; 0.6 min, 10% A; 5 min, 10% A; 7 min, 14% A; 13 min, 15%A ; 13.1–18 min, 100% A; 18.1–23 min, 7% A. The flow rate was 1.3 mL/min and the optimized detection wavelength was 258 nm. The quantitation limit of this analysis was approximately 0.16 µg/mL.
Quantitative Determination of NegundosideQuantitative determination of negundoside was carried out in accordance with the Herbal Medicines Compendium, V. negundo Leaf Dry Extract.20) Negundoside (5 mg) was weighed and dissolved in methanol as a standard solution. The concentration of negundoside in the standard solution was 1 mg/mL. Fine powdered leaves of V. negundo (1 g) were weighed, dissolved in 25 mL of methanol, extracted for 10 min in a water bath at 70°C, and centrifuged. The supernatant was transferred to a 100-mL beaker, and the residue was extracted with 10 mL of methanol three times. All supernatants were transferred to the 100-mL beaker. Then, the supernatant was concentrated at 70°C to 20 mL and filtrated. Powdered tablets and the contents of capsules or granules (daily dosage or recommended minimum daily intake) were weighed and extracted as previously mentioned. HPLC analysis was carried out on a YMC-Pack Pro 18 column (250 × 4.6 mm, 5 µm, YMC) at 25°C with a sample injection volume of 10 µL. The mobile phase consisted of 0.14 g/L potassium phosphate monobasic and 0.5 mL/L phosphoric acid aqueous solution (A) and acetonitrile (B), using a gradient elution program: 0 min; 90% A; 15 min, 85% A; 30–34.5 min, 80% A; 37.5 min, 85% A; 45 min, 90% A. The flow rate was 1 mL/min and the optimized detection wavelength was 254 nm. The quantitation limit of this analysis was approximately 0.03 µg/mL.
Disintegration TestA disintegration test was carried out in accordance with the Japanese pharmacopoeia <6.09> disintegration test.21) One dosage unit of the samples was placed in each of the six tubes of the basket. A disk was added for samples B, D, F, I, and K. Water at 37°C was used in the immersion fluid. The tests were carried out for 20 min for capsules, 60 min for coated tablets, and 30 min for plain tablets. Then, the baskets were lifted from the fluid. Complete disintegration was defined as a state in which any residue of the unit, except fragments of insoluble coating or capsule shell, remaining on the screen of the test apparatus or adhering to the lower surface of the disks, if used, is a soft mass with no palpably firm core.
PDA detector was used in this study. The detection wavelength was set at 275 nm, at which four chemical marker compounds of chasteberry (PHBA, homoorientin, agnuside, and casticin)10,14,19) could be abundantly detected. Chromatographic fingerprints of the chemical marker compounds, V. agnus-castus fruit dry extract (reference standard), and the test samples (medicinal product A and dietary supplements B–K) are shown in Fig. 1. The chromatographic fingerprint of the medicinal product A was similar to that of the reference standard. Conversely, the chromatographic fingerprints of the dietary supplements B–K were not similar to that of the reference standard and medicinal product A. For more detailed analysis, fifteen peaks were defined as characteristic peaks for comparisons among the reference standard, one medicinal product, and 10 dietary supplements. The characteristic peaks in the sample chromatograms were identified by comparing their relative retention times and UV spectra with that of the reference standard. After identification of each peak, peak area percentages were calculated and compared (Table 2). Results showed that all fifteen characteristic peaks were detected in the chromatogram of the medicinal product A, and its profile was similar to that of the reference standard. All fifteen characteristic peaks were also detected in samples C–E and I–K of dietary supplements; however, each peak area percentage showed heterogeneity. For example, the content of agnuside (peak No. 7, chemical marker compound) in samples C, D, and J was approximately 5%, which was much lower than that present in the reference standard and medicinal product A. Regarding the other dietary supplements (samples B, F–H), these profiles showed more heterogeneity, where some characteristic peaks were not detected or were small. In particular, six peaks in sample F and 10 peaks in sample G were missing in the chromatogram. These undetected and small peaks were probably specific to hydrophobic compounds because they appeared in the latter half of retention times. This finding suggested that these supplements (samples B, F–H) might be manufactured via extraction with a hydrophilic solvent, such as water or water containing a low concentration of hydrophobic solvent. The safety and efficacy of an oral preparation containing chasteberry extract marketed in Europe was evaluated by The Committee on the Herbal Medicinal Products (HMPC), a sub-organization of the European Medicines Agency, and a community herbal monograph was published in 2010.22) According to this monograph, the extraction solvent for preparation of chasteberry dry extract for “Well-established use” and “Traditional use” is 60 or 50–52% ethanol. In addition, the European Pharmacopoeia (EP)15) defines 40–80% ethanol as the extraction solvent for production of Agnus castus fruit dry extract. Therefore, it is noteworthy that there is lack of knowledge of the safety and efficacy of chasteberry extract produced by extraction with water or water containing a low concentration of hydrophobic solvent.
 |
a) Peak area percentage in this table was calculated from the each peak area to the sum of charasteristic 15 peak areas. b) Chemical marker compounds: p-hydroxybenzoic acid (No. 2), homoorientin (No. 6), agnuside (No. 7), and casticin (No. 15) are bold letters. c) Graphical image of the peak area percentage for each sample. The upper limit of the y-axis is 20.0% of peak area percentage. d) Reference standard of Vitex agnus-castus fruit dry extract. e) Not detected.
Figure 2 shows the sum of raw peak areas of the four chemical marker compounds per daily dosage of the samples. The total peak area of sample I was less than half that of sample A, regardless of the same amount of chasteberry extract (20 mg, Table 1). On the other hand, the total peak areas of samples B and E were almost equal to that of sample A although these samples were claimed to contain twice the amount of chasteberry extract present in sample A. The total peak areas of samples C, D, H, and J differed, although the labels of these samples suggested that they all contained 40 mg of chasteberry extract. Only a small fraction of the total peak area of samples F and G represented chasteberry extract amount in these products; additionally, this information was not included in the product label. As shown in Table 2, these products contained chasteberry extract of various qualities, which might be influenced by the less regulated manufacturing conditions, low-quality materials, and incorrect materials. Regarding sample K, the sum of the peak areas of the four chemical markers was approximately five-fold greater than that of sample A. According to the official website, sample K contains more than 40 mg chasteberry extract; therefore, higher contents of the markers might be appropriate. However, the safety of this large amount of chasteberry extract is questionable, although chasteberry has been used for long time, and no serious adverse effects have been reported.23)
Mesh, p-hydroxybenzoic acid; pale gray, homoorientin; dark gray, agnuside; black, casticin.
Peak analysis of the HPLC fingerprints showed that the quality of a few dietary supplements was unreliable. Thus, further quality assessment of the samples was performed using the chemometric method, PCA. PCA can help objectively assess chemical information, which has been used to analyse the chemical profiles of herbal products.24,25) Eleven samples with 15 characteristic peaks/each were submitted to PCA. The first and second principal components (PCs) showed 40.0 and 30.4% variability, respectively, and both PCs accounted for 70.4% of the total variance. Thus, the first two PCs concentrated the multidimensional information into a 2D dataset used to classify the samples. The score plot (Fig. 3I) showed that the samples could be divided into two groups: Group 1 including eight samples (A–E, I–K) and Group 2 including three samples (F, G, H). This corresponded to the different profiles shown in Table 2. These results indicated that samples F, G, and H were different in chemical composition from the other samples. For further analysis of this score plot, an enlarged score plot focusing on Group 1 was prepared (Fig. 3II). This figure showed that PC1 could divide the samples into three subgroups, whereas PC2 could differentiate between sample B and the other samples. This finding suggested that only two dietary supplements (E, I) were similar in composition to medicinal product A. The loading plots of PC1 and PC2 (Fig. 4) indicated that PHBA and agnuside positively, peak 3 and 4 negatively contributed to PC1, respectively; moreover, peaks 3 and 4 also contributed to PC2.
The number is related to the characteristic peaks in Table 2. PHBA, p-hydroxybenzoic acid.
Peak analysis of the HPLC fingerprints revealed quality concerns about dietary supplements. To further determine the quality of the dietary supplements, quantification of the marker compounds was carried out. Agnuside, a hydrophilic iridoid, and casticin, a hydrophobic flavonoid, were selected. They are quantitative compounds in the EP,14,15) USP,19) and WHO monographs.23) V. negundo, a different species of V. agnus-castus was included in this test for comparison because our previous study showed that on the basis of casticin to agnuside ratio, V. negundo might contaminate dietary supplements of chestberry.17)
First, casticin and agnuside were assayed in samples A–K and V. negundo according to the USP method. The contents of casticin and agnuside in each product per daily dosage were calculated (Table 3). The medicinal product A contained 0.228 mg casticin and 0.388 mg agnuside per daily dosage. However, dietary supplements showed a wide range, from “not detected” to 0.699 mg casticin and from “not detected” to 1.411 mg agnuside. Casticin and agnuside were present in very low amounts or not detected in dietary supplements F and G, which is in line with the results of HPLC fingerprinting shown in Table 2. The contents of these two markers in the dietary supplement K were higher than in the medicinal product A, which is in line with the integrated amount of the four analytical markers, including casticin and agnuside, shown in Fig. 2. To exclude the influence of different amounts of daily dosages of the dietary supplements, the percentage of marker compounds per each labeled ingredient was calculated (Table 3). The contents of casticin and agnuside in the medicinal product A were 1.142 and 1.938%, respectively. Although the label of the dietary supplement I claims that it contains the same amount of extract as the medicinal product A, sample I contained only 0.143% casticin (12.5% of casticin content in sample A), and 1.059% agnuside (54.6% of agnuside content in sample A). In addition, both samples B and E are claimed to contain approximately 40 mg of the extract, which is twice the amount present in sample A; however, sample B contained only 0.152% casticin, 1.018% agnuside (13.3, 52.5% of sample A), and sample E contained 0.435% casticin, 0.345% agnuside (38.0, 17.8% of sample A). Moreover, although the labels of the dietary supplements C, D, H, and J claimed that they contained the same amount of chasteberry, the contents of the two markers greatly varied. In particular, sample H contained only 0.006% casticin.
| Sample | Amount of chasteberry or its extract in products | Content in product (mg/d)a) | Content in ingredient (%)b) | Agnuside/casticinc) | Negundoside (%)b) | ||
|---|---|---|---|---|---|---|---|
| Casticin | Agnuside | Casticin | Agnuside | ||||
| A | 20 mg | 0.228 | 0.388 | 1.142 | 1.938 | 1.7 | N.D.d) |
| B | 40 mg | 0.061 | 0.407 | 0.152 | 1.018 | 6.7 | N.D. |
| C | 40 mge) | 0.186 | 0.099 | 0.465 | 0.247 | 0.5 | N.D. |
| D | 40 mge) | 0.043 | 0.047 | 0.108 | 0.118 | 1.1 | N.D. |
| E | 42 mg | 0.183 | 0.145 | 0.435 | 0.345 | 0.8 | N.D. |
| F | — | N.D. | 0.030 | — | — | — | N.D. |
| G | — | N.D. | N.D. | — | — | — | N.D. |
| H | 40 mge) | 0.003 | 0.097 | 0.006 | 0.244 | 32.5 | 0.031 |
| I | 20 mg | 0.029 | 0.212 | 0.143 | 1.059 | 7.3 | N.D. |
| J | 40 mg | 0.180 | 0.075 | 0.451 | 0.188 | 0.4 | N.D. |
| K | More than 40 mge) | 0.699 | 1.411 | — | — | 2.0 | N.D. |
| VNf) | — | — | — | 0.023 | 0.883 | 38.3 | 0.021 |
a) Content per the recommended daily dosage on the label. b) Content of herbal drug or extract in products. c) Agnuside to casticin ratio calculated based on their contents in products, except VN, in which it was calculated based on their contents in ingredients. d) Not detected. e) Official website information. f) Vitex negundo.
Our previous study showed that casticin to agnuside ratio could be a useful index to distinguish V. agnus-castus from its adulterant, V. negundo.17) Casticin to agnuside ratio of Sample H was 32.5, which is much higher than that of the medicinal product A (ratio: 1.7) and is almost equal to that of V. negundo leaf (ratio: 38.3). Furthermore, the content of negundoside, a characteristic chemical marker of V. negundo, was determined according to the herbal monograph of V. negundo Leaf Dry Extract published in the Herbal Medicines Compendium20) (Table 3). Negundoside was detected in sample H (0.031%); however, it was not detected in the reference standard or other samples. The spectrum of sample H was identical to the peak of negundoside. This result is consistent with the results of casticin to agnuside ratio. These data suggested that V. negundo might be the source or one of the sources of the starting materials in sample H.
Disintegration TestDietary supplements are generally formulated as capsules or tablets in Japan. A few studies reported that some supplements containing chasteberry extract, ginkgo leaf extract, or chondroitin sulfate did not disintegrate within the time defined in the pharmacopoeia.1,26) In accordance with these results, we performed a disintegration test and assessed the formulation quality. The disintegration test was performed using water maintained at 37°C as an immersion fluid according to the Japanese Pharmacopoeia (JP17). Of the 10 samples, one medicinal product and seven dietary supplements completely disintegrated within the defined time (Table 4), whereas two dietary supplements did not disintegrate within the test time. Of the two supplements, two sample F plain tablets disintegrated at approximately 20 min; however, other 4 tablets did not disintegrate within 30 min. This result suggested that sample F was not manufactured under sufficient control to assure homogenous hardness. Another supplement, sample J (soft capsule) showed prompt shell disintegration; however, its content did not disperse within the test time. Therefore, it was concluded that sample J did not conform with the criterion of the JP 17.
| Sample | Dosage form | Test result | Test time (min) | Time for disintegration (min) | Average | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | |||||
| A | Coated tablet | ○ | 60 | 7.3 | 6.8 | 8.0 | 7.8 | 8.5 | 8.6 | 7.8 |
| B | Hard capsule | ○ | 20 | 12.4 | 7.9 | 10.8 | 11.5 | 10.1 | 13.3 | 11.0 |
| D | Hard capsule | ○ | 20 | 6.4 | 6.8 | 6.8 | 6.4 | 6.4 | 6.4 | 6.5 |
| E | Plain tablet | ○ | 30 | 23.9 | 22.9 | 26.5 | 25.1 | 23.0 | 19.6 | 23.5 |
| F | Plain tablet | × | 30 | >30 | 18.8 | >30 | >30 | >30 | 22.7 | — |
| G | Coated tablet | ○ | 60 | 17.2 | 15.7 | 16.4 | 16.2 | 16.2 | 18.1 | 16.6 |
| H | Plain tablet | ○ | 30 | 25.3 | 21.6 | 25.3 | 25.6 | 23.3 | 22.0 | 23.9 |
| I | Hard capsule | ○ | 20 | 9.5 | 7.0 | 7.4 | 6.0 | 6.3 | 10.0 | 7.7 |
| J | Soft capsule | × | 20 | >20 | >20 | >20 | >20 | >20 | >20 | >20 |
| K | Hard capsule | ○ | 20 | 11.1 | 15.7 | 16.3 | 18.6 | 18.1 | 15.7 | 15.9 |
○: All samples disintegrated within the defined test time; ×: Disintegration of samples incompatible with the test criteria. a) Sample C (granule) was not tested because all granules passed through the no. 30 (500 µm) sieve.
As previously mentioned in literature,26,27) a disintegration test of dietary supplements is not mandated by the Food Sanitation Law because even if these products do not disintegrate in the digestive tract, their safety, but not their efficacy, is ensured. Although the safety is the most important aspect in foods; however, consumers actually purchase the products for some benefits to their bodies. Therefore, manufactures of dietary supplements should take the good quality of these products into consideration.
This study showed that some dietary supplements may contain chasteberry extract of inadequate quality and/or incorrect origin. Meanwhile, some dietary supplements like samples E and I contained similar characteristics of extract to medicinal product A. In addition, dietary supplements F and H did not disintegrate within the defined time, which indicated that they might not be manufactured under well-regulated conditions.
Although more investigations are still needed, the methods used in this study might provide useful tools for quality evaluation of various products containing not only chasteberry extract but also other herbal extracts by comparing their HPLC profiles, PCA, quantitative determination of the marker compounds, and disintegration test.
A part of this study was supported by AMED under Grant Number JP16ak0101030j0503 for joint research projects within industry, universities and national research institutes.
The authors declare no conflict of interest.
