INTRODUCTION:
Carotenoids represent a large family of natural
pigments produced in plant foods. They are identified by their chemical structure
as a hydrocarbon chain without oxygen (Carotenes) or in the presence of
oxygenated derivatives (Xanthophylls). Numerous studies highlight the favorable
properties of carotenoids for health. Indeed, they have antioxidant properties
which help preserve cellular youth. They are generally involved in the
prevention and treatment of eye pathologies such as cataracts and even
age-related degeneration of the macula of the eye through lutein, or by the
prevention of prostate cancer through lycopene1-5. In addition,
certain carotenoids play the role of precursors of vitamin A. Furthermore,
these molecules are involved in oxidation phenomena through their sensitivity
to oxidation, leading to organoleptic and nutritional loss of foods5,6.
Carotenoids are very common Phyto micronutrients in fruits and vegetables.
Studies have shown they are also in mung bean seeds7.
Mung bean (Figure 1) is a grain legume from the
Fabaceae family and native to India. It is a fast-growing legume (< 60 days)
adapted to tropical and subtropical zones. It was introduced in Burkina Faso in
the 1920s to increase the supply of legumes and contribute to the resilience of
populations in the face of food insecurity. Studies have shown that consuming
mung bean seed products could prevent or treat certain chronic diseases such as
cancers, inflammation, and cardiovascular problems8,9. Indeed, raw,
and mature mung bean seeds are provided in nutrients such as carbohydrates,
proteins, fiber, minerals elements, phenolic compounds. A recent study on 84
mung bean varieties from India and Australia showed that the seeds are rich in
carotenoids with contents varying from 6 to 33mg of β-carotene
equivalent/100g of dry seeds7,10.
Given these dietary and therapeutic indications for
mung bean seeds, we focused our research on the structural characterization and
identification of the majority of carotenoids in the seeds of this plant. The
identification was carried out by HPLC-MS/MS to establish a relationship
between the identified metabolites based on their spectroscopic
characteristics, fragmentation modes, and retention times. The results of this
work will contribute to the valorization of mung bean seeds as a natural source
of carotenoids.
MATERIALS AND METHODS:
Vegetal material and chemicals:
This study focused on the seeds of various mung bean
of Australian origin and acclimated to Burkina Faso. They were cultivated and
harvested in Saria (12°16' N; 02°09' W) by the Plant Genetics and
Biotechnologies laboratory of the Ministry of the Environment. The collected
seeds were stored in PICS-type triple-bottom bags (Perdum Improve bag for
Cowpea Storage) for later work.
Figure 1: Mung bean seeds
The chemicals used were n-hexane, acetone,
β-carotene (standard), acetonitrile, methanol, and formic acid.
We used ultra-pure quality water (conductivity 0.18
µS/cm).
Extraction:
A portion of 100g of mung bean seeds ground
into powder was macerated for 24hours at 4°C with an equal volume mixture of
the solvents acetone and n-hexane. A Büchner filtration system using Whatman No
4-filter paper made it possible to obtain filtered extracts. The
extraction procedure was repeated twice successively with the grounds. The
filtrates obtained were collected and concentrated under reduced pressure
(T<40°C)11.
Saponification:
This is the first stage in the purification
of carotenoids in extracts. Now, 30% methanolic potassium hydroxide (KOH) was
added to the concentrated extract obtained previously. After stirring, the
mixture was left to stand for 4 hours. After liquid-liquid partitioning with
hexane, the upper phase (organic phase) was recovered and then concentrated
using a vacuum evapo-concentrator at a temperature below 40°C. The crude
extract obtained, rich in carotenoids and free of waxes and chlorophylls, was
dried in a desiccator and then stored at 4°C for subsequent analysis7,12.
Thin-layer chromatography (TLC):
TLC is based on the separation of chemical compounds
by migration and adsorption on a support (polar stationary phase), in a mobile
phase (eluent), depending on their nature, the eluting power of the mobile
phase and the adsorbing power of the support.
In this study, the stationary phase is a 60 F254 silica
gel layer fixed on a 20x20cm aluminum plate. The eluent is a solvent mixture
consisting of petroleum ether/acetone/dichloromethane (3:1:1; v/v).
UV-visible spectrophotometry:
The principle of UV-visible spectrophotometry is based
on the absorption of radiation by molecules in the range from ultraviolet
(0.2µm to 0.4µm) to visible (0.4µm to 0.8 µm).
Thus, based on the thin layer chromatographic profile
results, each spot was collected and redissolved in ethanol. The principle
passed approximately 2mL of extract through a variable monochromatic light
source from a SAFAS 190 Double Energy System type spectrophotometer.
Identification of carotenoids by HPLC-MS/MS:
The V. radiata extract was characterized by
high performance liquid chromatography (HPLC) of the Agilent infinitely better
1290 technology type, coupled with mass spectrometry (MS). A Water X-terra C18
type column (100 x 2.1mm; 5µm) was used to carry out the HPLC separation. Ion
monitoring was carried out in MS/MS in positive mode ionization (ESI+).
The mobile phase is prepared from two solvents A and B. The elution is carried
out by gradient with a flow rate of 0.6mL/min. Solvent A consists of a mixture
of acetonitrile and methanol (85% and 15%) and is acidified with 0.1% formic
acid; solvent B consists of water acidified with 0.1% formic acid. Elution
began with an initial composition of 95% solvent A and 5% solvent B for 7 min.
Then the gradient was maintained at 100% A for 8 min. The injection volume is
50 μL. The flow rate of the carrier gas (N2) was 10 L/min and
its temperature was maintained at 200 °C with a pressure of 15 psi. The Mass
Spectrometer has been calibrated to detect molecular ions with masses m/z
between 100 and 1000 u. The data obtained is processed by Agilent Mass Avion
Express CMS software. The molecular identification of carotenoids is carried
out by comparing the molecular weight of each fragment obtained as a function
of its retention time.
RESULTS AND DISCUSSIONS:
Thin layer chromatography and UV-visible
spectrophotometry:
The chromatogram profile obtained from the crude
saponified extract revealed two
spots with frontal references: 
and 0.87 respectively characterizing
xanthophylls and carotenes (Figure
3). Indeed, xanthophylls (astaxanthin, cryptoxanthin, lutein, violaxanthin,
zeaxanthin, capsanthin, etc.) are polar compounds possessing various oxygenated
functional groups such as alcohols, ketones, and aldehydes, among others13.
This polar character allows them a great affinity with the equally polar
stationary phase (silica) and will be more retained, which explains the low 
observed for these compounds. On the other
hand, carotenes, the most commonly encountered of which are β-carotene and
lycopene, are generally non-polar compounds made up only of carbon and hydrogen
elements and, therefore, less retained by silica, which explains their high compared to that of xanthophylls.
The UV-visible spectrum of the spots each showed an
absorption maximum of 450nm (Figure 3). Indeed, carotenoids absorb in the blue
and little in the green (maximum around 420, 440 and 460nm). This property is
due to the conjugated double bonds of the pigments and linked to the
yellow-orange color of the carotenoids. In fact, xanthophylls are hydroxylated
carotenes (Figure 2), which explains their observed almost identical absorption
range.
Although the conjugation of carotenoids constitutes a favorable
factor for obtaining spectrophotometric data in the UV-visible region, it also
makes them sensitive to heat, the process of oxidation and isomerization,
acidic conditions or basic thus generating their degradation. This leads to
difficulties when analyzing them14.
Figure 2: Structures of carotenoids
Identification of the majority of carotenoids:
Carotenoids have two main classifications: carotenes
and xanthophylls. Carotenoids exhibit more stable protonation in the positive
mode [M+H]+15. This is why the crude extract was analyzed in this
polarity. In addition, the presence of functional groups in the structure of
xanthophylls determines the spectral properties and the generation of
characteristic fragments in mass and spectrometry, enabling the compound to be
identified15.
HPLC spectrum of the saponified crude extract of mung
bean seeds yielded several signals likely to correspond to carotenoids (Figure
4).
Figure 4: HPLC
chromatogram of the crude saponified mung bean extract
Three of these peaks (A: tR = 1.78 min (peak
6); B: tR = 8 min (peak 14) and C: tR = 9.44 min (peak
15)) were subject to identification in tandem mass spectrometry.
The mass spectrum of the signal at 1.78 min (compound A)
shows a molecular ion [M+H]+ at m/z 553 (crude formula C40H56O).
This molecular could correspond to cryptoxanthin derivatives
(α-cryptoxanthin or β-cryptoxanthin)4. Indeed, these two molecules are differentiated by
the position of the hydroxyl group which is allylic in the structure of
α-cryptoxanthin allowing ease of its elimination while in the structure of
β-cryptoxanthin this group is linked to an atom of secondary carbon close
to saturated carbon-carbon bonds. In addition, we observe a difference in the
position of the double bond of the second nucleus of the two molecules (Figure
5).
Figure 5: position of the hydroxyl group of
α-cryptoxanthin and β-cryptoxanthin
This characteristic allows us to observe a differentiation
in the spectral behavior between the two compounds; since the hydroxyl group in
α-cryptoxanthin is allylic, we would observe an ion at m/z 535
corresponding to the loss of a water molecular [M+H-H2O]+
more intense and more stable compared to the molecular ion at m/z 55313.
Analysis of the mass spectrum of compound A reveals that the fragment ion peak
at m/z 535 is less intense (low abundance) than that of the molecular ion at
m/z 553. This could be explained by the instability of the ion at m/z 553
leading to its fragmentation, hence the peak detected at m/z 495 [M+H-H2O-40]+.
This peak could correspond to the fragment obtained by internal breakage of the
hydroxyl ring (Figure 6). Also, several low-abundance fragment ions
corresponding to cleavages of the polyene chain were detected at m/z 477, m/z
314, m/z 240, and m/z 182. Thus, compound A would be β-cryptoxanthin, a
commonly encountered provitamin A carotenoid.
Figure 6: MS/MS spectrum of compound A (m/z 553)
β-cryptoxanthin is a carotenoid with therapeutic
properties for bone health. Indeed, it is involved in bone formation, as well
as in the inhibition of osteoclastic bone resorption, in bone loss induced by
lipopolysaccharides (in vivo), and in preventing osteoporosis in women16.
The signal at tR = 8 min (compound B) would
match a molecular ion at m/z 431 in agreement with the mass calculated using
the crude formula C29H50O2. It could
correspond to α-tocopherol (vitamin E), an apo-carotenoid. Examination of
the mass spectrum (Figure 8) shows a fragment ion at m/z 413 corresponding to
the loss of a water molecule. The presence of this ion suggests the presence of
an OH group in the molecular structure of the compound. The fragment ion
observed at m/z 167 suggests a retro-Diels-Alder type fragmentation between the
bond at position 
and 
and the carbon-carbon bond at position 
and 
of the chromanol ring (Figure 7). This
fragmentation pattern is commonly encountered in vitamin E metabolites17.
Also, a fragment ion is observed at m/z 207 ([M+H-C16H33]
corresponding to the loss of the side carbon chain (phytyl chain). Based on
these fragmentation models, the structure of compound B would be l'
α-tocopherol.
Figure 7:
retro-Diels-Alder fragmentation of α-tocopherol
Figure 8: MS/MS
spectrum of compound B (m/z 431)
Tocopherols are derivatives of vitamin E and can be
classified according to the number and position of the methyl alkyls on the
chromanol. These criteria make it possible to distinguish α-tocopherols,
β-tocopherols, γ-tocopherols and δ-tocopherols.
α-Tocopherol in particular is preferentially assimilated and accumulated
in humans. According to the literature, the latter has very interesting
biological activity17-19. Indeed, these bioactive molecules, through
their antioxidant and anti-inflammatory activities, are recognized for their
beneficial effects on the health of consumers.
Previous studies have revealed that mung bean seeds
are rich in tocopherols and can be considered as a natural resource of
nutraceutical foodstuffs due to their marked pharmacological property such as
antioxidant and anti-inflammatory powers19,20.
The mass spectrum of the compound eluted at tR
= 9.44 min (compound C), indicates a molecular ion [M+H]+ at m/z 537
in agreement with the mass calculated using the crude formula C40H56.
This molecular ion could correspond to beta-carotene, alpha-carotene,
gamma-carotene, epsilon-carotene, or lycopene. Analysis of the CID (Colision
Induced Dissociation) spectrum shows the presence of a fragment ion at m/z 416
corresponding to the loss of 121 u. This fragment ion obtained would be due to
the elimination of the ring in the structure of β-carotene. Indeed,
authors have shown that in atmospheric pressure chemical ionization mass
spectrometry (APCI) of β-carotene, a fragment ion at m/z 413 is obtained
and corresponds to the loss of an ionone fragment of the molecule. protonated
(cycle elimination)21. Harina and Ramirez showed that mung bean
carotenoids are present as β-carotene and xanthophyll22. The
fragment ion observed at m/z 282 is obtained by breaking the carbon-carbon bond
at position 
and 
or 
and 
(Figure 9). Based on this information as
well as literature data, compound C would be β-carotene.
Figure 9: MS/MS spectrum of compound C (m/z
537)
β-carotene is the most powerful precursor of
vitamin A, a very important vitamin at all ages for eye health. It has
significant antioxidant activity due to its conjugated double bonds, which
allow the incorporation of free radicals and facilitate the delocalization of
the charge along the chain.
Studies have demonstrated the potential of carotenes
in preventing and treating multiple pathologies. For example, a relationship
was established between β-carotene intake and a reduction in prostate
cancer by 15 % and lung cancer by 15 % to 30% 23,24. Additionally,
interesting results have been observed in protection against ionizing radiation
such as infrared and ultraviolet rays25. Also, topical formulations
have shown anti-aging and skin lightening effects26, thus becoming
an interesting prospect for designing blockers and active compounds in cosmetic
and dermatological treatments.
It is interesting to emphasize that, although
saponification generates losses of analytes, as well as their degradations27,
many carotenoids were observed and three of them were identified by their
structure. Saponification facilitates the ionization of carotenoids and the
suppression of high background noise.
Likewise, given the great diversity of carotenoid
structures and in some cases their similarity, it was necessary to exploit the
performance of HPLC for efficient separation of the different compounds. The
choice of column was of very important as C18 presents an advantage
for good resolution and chromatographic separation particularly for
carotenoids. It has greater stability at high pH, high speed, and low cost.
Furthermore, it could present a disadvantage when analyzing more complex
matrices such as cis- and trans-carotenoid isomers28. However, the
information provided by HPLC alone is insufficient in an identification
process. Therefore, HPLC was coupled with a mass spectrometer (MS). This
provided information on the mass-charge (m/z) relationship and fragmentation
patterns characteristic of each compound, essential during identification.
Finally, among the ionization techniques compatible
with HPLC-MS, the most used in the study of carotenoids are APCI) and ESI29.
ESI was used in this study because it is a useful technique for analyzing
high-polarity compounds such as xanthophylls and low-polarity compounds such as
carotenes29.
CONCLUSION:
Nowadays, many techniques chemical, physical, and
chromatographic are used for the structural analysis of bioactive compounds.
The high-performance liquid chromatography and electrospray ionization mass
spectrometry tandem enabled this study to identify and establish the probable
molecular structures of a few carotenoids present mainly in mung bean seeds.
β-cryptoxanthin, α-tocopherol (vitamin E), and β-carotene were
identified. These compounds have notable impacts on consumers' health. This
demonstrates that mung beans are a natural source of carotenoids. The
HPLC-MS/MS technique becomes a powerful tool in the structural study of natural
products, such as analyzing the carotenoid profile in crude extracts.
ACKNOWLEDGEMENT:
The authors acknowledge INERA (Institute of the
Environment and Agricultural Research) and ANSSEAT (National agency for the
safety of the environment, food, work and health products for their material
contribution.
CONFLICT OF INTEREST:
The authors declare that there are no competing
interests.
REFERENCES:
1. N.O. Odongo, G.O. Abong, M.W. Okoth and E.G.
Karuri. Development of High Protein and Vitamin A Flakes from Sweet Potato
Roots and Leaves. Open Access Library Journal. 2015; 2: e1573 http:// dx.doi.org/10.4236/oalib.1101573
2. P. Fraser and P. Bramley. The biosynthesis
and nutritional uses of carotenoids. Prog. Lipid Res., 2004; 43(3): 128–265, https://doi.org/10.1016/j.plipres.2003.10.002
3. S.K. Dominique, H. Adama, K. Moumouni, S.
Koussao, P. Eloi, T. S. Issa, D. Pierre et N. Mouhoussine. Evaluation des
teneurs en antioxydants et micronutriments des feuilles de onze variétés de
Ipomoea batatas à chairs orange et pourpre produits au Burkina Faso. J. Soc.
Ouest-Afr. Chim, 2020; 050: 1-10.
4. M. Koala. Étude d’Ipomoea batatas (patate
douce à chair orange) : structures et propriétés biologiques, Thèse Dr.
unique, Univ. Ouagadougou, p. 191, (2015).
5. C. Chanforan. Stabilité de microconstituants
de la tomate (composés phénoliques, caroténoïdes, vitamines C et E) au cours
des procédés de transformation : études en systèmes modèles, mise au
point d’un modèle stoechio-cinétique et validation pour l’étape unitaire de pr.
Thèse Dr. , Univ. d’Avignon des Pays Vauclus., pp. 57–113, (2010).
6. C.M.G. Renard, C. Caris-Veyrat, C. Dufour et C. Bourvellec. Le devenir des polyphénols
et caroténoïdes dans les fruits et légumes traités thermiquement. Innovations
Agronomiques, 2014; 42: 125-137. https://hal.inrae.fr/hal-02629481
7. O. Mahamadi. Comparaison des teneurs en
phytonutriments dans les variétés de Vigna radiata (Mung bean) produits dans
les conditions agro-écologiques du Burkina Faso. Thèse de doctorat unique.
Université Joseph KI-ZERBO. 2022; 89-145.
8. G. Maiani, M.J.P. Caston, G. Catasta, E.
Toti, I.G. Cambrodon, A. Bysted, F. Granado-Lorencio, B. Olmedilla-Alonso, P.
Knuthsen, M. Valoti, V. Bohm, E. Mayer-Miebach, D. Behsnilian and U. Schlemmer.
Carotenoids: Actual knowledge on food sources, intakes, stability and
bioavailability and their protective role in humans. Molecular Nutrition and
Food Research, 2009; 53: S194-S218. https://doi.org/10.1002/mnfr.200800053
9. K. Gandhimaniyan, S. Dinesh Kumar, A.
Sabaridasan, and K. Jayaprakash, Effet of Gracilaria Verrucosa SLF by alcohol
aqueous method on Vigna radiata, IJRSr, 2019; 10, no. 07(1): 34016–34019,. https://dx.doi.org/10.24327/ijrsr.2019.1008.3754
10. O. Mahamadi, H. Adama, W.F.M. Serge, J.T.
Benoit, P. Eloi, and N. Mouhoussine, Détermination des paramètres
physico-chimiques et des teneurs en micronutriments antioxydants de dix
variétés de mung bean (Vigna radiata) produits dans les conditions agroécologiques
du Burkina Faso, JCBPS, 2021; 11(2): 254–274, https://doi.org10.24214/jcbps.B.11.2.25474.
11. K. Moumouni, A. Hema S. Koussao, E. Palé, S.
Abdoulaye, B. Jerome, M. Nacro, Evaluation of Eight Orange Fleshed Sweetpotato
(OFSP) Varieties for Their Total Antioxidant, Total Carotenoid and Polyphenolic
Contents. Journal of Natural Sciences Research, 2013; 3(4): 67- 72.
12. S.K. Dominique. Micronutriments et
contribution à la selection de variétés de la patate douce (Ipomea batatas
Lam.) à chair orange et pourpre du Burkina Faso. Thèse de doctorat unique.
Université Joseph KI-ZERBO. Pages 123-143, (2021).
13. C.U. Mussagy, J. Winterburn, V.C.
Santos-Ebinuma, J.F.B. Pereira. Production and Extraction of Carotenoids
Produced by Microorganisms. Applied Microbiology and Biotechnology, 2019; 103(3):
1095–1114. https://doi.org/10.1007/s00253-018-9557-5
14. J.G. Provesi, C.O. Dias, E.R. Amante.
Changes in Carotenoids during Processing and Storage of Pumpkin Puree. Food
Chemistry, 2011; 128(1): 195–202, https://doi.org/10.1016/ J.FOODCHEM.2011.03.027.
15. L.R.B. Mariutti, D.M. Pereira, A.Z.
Mercadante, P. Valentão, N. Teixeira, P.B. Andrade. Further Insights on the
Carotenoid Profile of the Echinoderm Marthasterias Glacialis L. Marine Drugs. 2012;
10(7): 1498–1510. https://doi.org/10.3390/md10071498
16. C. Matsumoto, N. Ashida, S. Yokoyama, T.
Tominari, M. Hirata, K. Ogawa, M. Sugiura, M. Yano, M. Inada, C. Miyaura. The
Protective Effects of β-Cryptoxanthin on Inflammatory Bone Resorption in a
Mouse Experimental Model of Periodontitis. Biosci Biotechnol Biochem. 2013; 77(4):
860–862. https://doi.org/ 10.1271/BBB.120791
17. S. Munné-Bosch and L. Alegre, The function
of tocopherols and tocotrienols in plants, Crit Rev Plant Sci. 2002; 21(1): 31–57,
https://doi.org/10.1080/0735-260291044179
18. S. Fereidoon, and C. Adriano. Tocopherol and
tocotrienol in common and Emergin Dietary Sources: Occurrence, Applications,
and Health. Int. J. Mol. Sci. 2016; 17(10): 1745, https://doi.org/ 10.3390/ijms17101745
19. A. Rani, V. Kumar, S.K. Verma, A.K. Shakya,
and G.S. Chauhan. Tocopherol content and profile of soybean: genotypic
variability and correlation studies, J Amer Oil Chem Soc, vol. 84, pp. 377–383,
(2007). https://doi.org/10.1007/s11746-007-1040-x
20. E.H. Kim, P. Seguin, J.H. Lee, and I. M.
Chung. Comparison of tocopherols contents in adzuki bean (Vigna angularis)
genotypes traits. Int J Agric Biol. 2013; 15(1): 179–180.
21. B. Richard, Breemen, D. Linlin, and D. P.
Natasa. Atmospheric pressure chemical ionization tandem mass spectrometry of
carotenoids. Int. J. Mass Spectrom. 2012; 312: 163–172.
https //doi.org/10.1016/j.ijms.2011.07.030
22. P.K. Dahiya, A.R. Linnemann, M.A.J.S. Van
Boekel, N. Khetarpaul, R.B. Grewal, and M.J.R. Nout. Mung bean: Technological
and Nutritional Potential. Critical Reviews in Food Science and Nutrition.
2015; 55: 670-688 https://doi.org/ 10.1080/10408398.2012.671202
23. Rowles, J.L.; Erdman, J.W. Carotenoids and
Their Role in Cancer Prevention. Biochimica et Biophysica Acta (BBA) -
Molecular and Cell Biology of Lipids. 2020; 1865 (11): 158613. https://doi.org/
10.1016/J.BBALIP.2020.158613.
24. J.L. Rowles, K.M. Ranard, C.C. Applegate, S.
Jeon, R. An, J.W. Erdman. Processed and Raw Tomato Consumption and Risk of
Prostate Cancer: A Systematic Review and Dose–Response Meta-Analysis. Prostate
Cancer and Prostatic Diseases. 2017; 21(3): 319–336.
https://doi.org/10.1038/s41391-017-0005-
25. W. Stahl, H. Sies. β-Carotene and Other
Carotenoids in Protection from Sunlight. Am J Clin Nutr. 2012; 96(5), https://doi.org/
10.3945/AJCN.112.034819
26. A.J. Meléndez-Martínez, C.M. Stinco, P.
Mapelli-Brahm. Skin Carotenoids in Public Health and Nutricosmetics: The
Emerging Roles and Applications of the UV Radiation Absorbing Colourless
Carotenoids Phytoene and Phytofluene. Nutrients, 2012; 11(5):,
https://doi.org/10.3390/NU11051093
27. U. Schweiggert, D.R. Kammerer, R. Carle, A.
Schieber. Characterization of Carotenoids and Carotenoid Esters in Red Pepper
Pods (Capsicum Annuum L.) by High Performance Liquid Chromatography/Atmospheric
Pressure Chemical Ionization Mass Spectrometry. Rapid Communications in Mass
Spectrometry, 2005; 19(18): 2617–2628. https://doi.org/10.1002/rcm.2104.
28. S. Saha, S. Walia, K. Sharma, K. Banerjee.
Suitability of Stationary Phase for LC Analysis of Biomolecules. Crit Rev Food
Sci Nutr. 2020; 60(17): 2856–2873, https://doi.org/10.1080/ 10408398.2019.1665494
29. R.B. van Breemen, L. Dong, N.D. Pajkovic.
Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry of
Carotenoids. International Journal of Mass Spectrometry. 2012; 312: 163–172, https://doi.org/10.1016/j.ijms.2011.07.030
|
Available online from December 27, 2024
|
and 
corresponding respectively to xanthophylls
and carotenes. The UV-visible spectra of the spots each showed an absorption
maximum of 450nm. HPLC-MS/MS analysis identified the structures of three
carotenoids: β-cryptoxanthin, α-tocopherol, and β-carotene. These compounds identified in V.
radiata seeds are very useful in many fields, including pharmaceutical,
agri-food and biological. The
HPLC-MS/MS technique represents one of the useful and efficient tools for the
identification of bioactive substances in crude extracts.