Introduction: Currently Moringa oleifera Lam., native to Asia, is widely distributed also in Europe [1]. Moringa leaves have been characterized to contain considerable amounts of various nutrients, as proteins, fiber and minerals [2]. Additionally, the leaves are reported to contain many types of antioxidant compounds. Various preparations of M. oleifera are used for their healthy properties [3]. Methods: The impact of different extraction methods (maceration, homogenization, Naviglio extractor, microwave-assisted extraction -MAE-, ultrasonic-assisted extraction -UAE-) on M. oleifera phenolic profile was studied. Alcoholic and hydroalcoholic extracts were analyzed by UHPLC/QTOF-MS. Phenolic profiles were compared using an untargeted metabolomics-based approach followed by multivariate statistics [4]. Results: Metabolomic approach allowed to putatively identify 262 phenolic compounds, namely 36 anthocyanins, 46 flavonols, 35 flavanols, 17 lignans, 16 alkylphenols, 45 tyrosols, 60 phenolic acids and 7 stilbenes. In particular, glycosidic forms of quercetin were the most characterizing compounds among the flavonoids group; besides, protocatechuic acid was found to be the most abundant hydroxybenzaldheyde, while the isomeric forms of hydroxybenzoic acid characterized the phenolic acids' class. Ultra-turrax homogenization showed higher total phenolic content (33.3 mg/g DW) than UAE (26.3 mg/g DW) and MAE (22.4 mg/g DW). Furthermore, by the Fold-Change analysis carried out on each phenolic sub-class, Naviglio extractor resulted to recover less common compounds such as chalcones, curcuminoids, hydroxycoumarins, and stilbenes, when compared with samples extracted with Ultra-turrax. Conclusions: The results of this work suggest that extraction method had a significant effect on yield and profile of phenolic compounds from M. oleifera leaves. The untargeted metabolomics analysis was a powerful tool for characterizing phenolic profile in the different extracts. The optimization of M. oleifera phenol extraction could be useful for the design of functional foods and nutraceuticals. References 1. Stohs S.J., Hartman M.J., Phytotherapy Research, 29, 796 (2015). 2. El Sohaimy S.A., Hamad G.M., Mohamed S.E. et al., Global Advanced Research Journal of Agricultural Science, 4, 188 (2015). 3. Brilhante, R.S.N., Sales, J.A., Pereira, V.S. et al., Asian Pacific Journal of Tropical Medicine 10, 621 (2017). 4. Rocchetti, G., Chiodelli, G., Giuberti, G. et al., Journal of Functional Foods, 40, pp. 564-572 (2018).
Impact of conventional and non-conventional extraction methods on the untargeted phenolic profile of Moringa oleifera leaves
Blasi F.;Montesano D.;Marcotullio M. C.;Sabatini S.;Cossignani L.
2018
Abstract
Introduction: Currently Moringa oleifera Lam., native to Asia, is widely distributed also in Europe [1]. Moringa leaves have been characterized to contain considerable amounts of various nutrients, as proteins, fiber and minerals [2]. Additionally, the leaves are reported to contain many types of antioxidant compounds. Various preparations of M. oleifera are used for their healthy properties [3]. Methods: The impact of different extraction methods (maceration, homogenization, Naviglio extractor, microwave-assisted extraction -MAE-, ultrasonic-assisted extraction -UAE-) on M. oleifera phenolic profile was studied. Alcoholic and hydroalcoholic extracts were analyzed by UHPLC/QTOF-MS. Phenolic profiles were compared using an untargeted metabolomics-based approach followed by multivariate statistics [4]. Results: Metabolomic approach allowed to putatively identify 262 phenolic compounds, namely 36 anthocyanins, 46 flavonols, 35 flavanols, 17 lignans, 16 alkylphenols, 45 tyrosols, 60 phenolic acids and 7 stilbenes. In particular, glycosidic forms of quercetin were the most characterizing compounds among the flavonoids group; besides, protocatechuic acid was found to be the most abundant hydroxybenzaldheyde, while the isomeric forms of hydroxybenzoic acid characterized the phenolic acids' class. Ultra-turrax homogenization showed higher total phenolic content (33.3 mg/g DW) than UAE (26.3 mg/g DW) and MAE (22.4 mg/g DW). Furthermore, by the Fold-Change analysis carried out on each phenolic sub-class, Naviglio extractor resulted to recover less common compounds such as chalcones, curcuminoids, hydroxycoumarins, and stilbenes, when compared with samples extracted with Ultra-turrax. Conclusions: The results of this work suggest that extraction method had a significant effect on yield and profile of phenolic compounds from M. oleifera leaves. The untargeted metabolomics analysis was a powerful tool for characterizing phenolic profile in the different extracts. The optimization of M. oleifera phenol extraction could be useful for the design of functional foods and nutraceuticals. References 1. Stohs S.J., Hartman M.J., Phytotherapy Research, 29, 796 (2015). 2. El Sohaimy S.A., Hamad G.M., Mohamed S.E. et al., Global Advanced Research Journal of Agricultural Science, 4, 188 (2015). 3. Brilhante, R.S.N., Sales, J.A., Pereira, V.S. et al., Asian Pacific Journal of Tropical Medicine 10, 621 (2017). 4. Rocchetti, G., Chiodelli, G., Giuberti, G. et al., Journal of Functional Foods, 40, pp. 564-572 (2018).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
