Moringa plants: Bioactive compounds and promising applications in food products

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Moringa oleifera—Storage Stability, In Vitro-Simulated Digestion and Cytotoxicity Assessment of Microencapsulated Extract

Moringa extract was microencapsulated for the first time by spray-drying technique using tragacanth gum (MorTG) to improve its stability under gastrointestinal and storage conditions, assessing total polyphenolic content (TPC) and antioxidant activity. Additionally, cytotoxicity of the microencapsulated components was evaluated after contact with Caco-2 cells. Results showed that TPC was released as follows—oral (9.7%) < gastric (35.2%) < intestinal (57.6%). In addition, the antioxidant activity in in vitro digestion reached up to 16.76 ±0.15 mg GAE g−1, which was 300% higher than the initial value. Furthermore, microencapsulated moringa extract presented a half-life up to 45 days of storage, where the noticeably change was observed at 35 °C and 52.9% relative humidity. Finally, direct treatment with 0.125 mg mL−1 MorTG on Caco-2 cells showed a slight antiproliferative effect, with a cell viability of approx. 87%. Caco-2 cells’ viability demonstrated non-cytotoxicity, supporting the safety of the proposed formulation and potential use within the food field.

Effect of microvesicles from Moringa oleifera containing miRNA on proliferation and apoptosis in tumor cell lines

Human microvesicles are key mediators of cell-cell communication. Exosomes function as microRNA transporters, playing a crucial role in physiological and pathological processes. Plant microvesicles (MVs) display similar features to mammalian exosomes, and these MVs might enhance plant microRNA delivery in mammals. Considering that plant microRNAs have been newly identified as bioactive constituents in medicinal plants, and that their potential role as regulators in mammals has been underlined, in this study, we characterized MVs purified from Moringa oleifera seeds aqueous extract (MOES MVs) and used flow cytometry methods to quantify the ability to deliver their content to host cells. The microRNAs present in MOES MVs were characterized, and through a bioinformatic analysis, specific human apoptosis-related target genes of plant miRNAs were identified. In tumor cell lines, MOES MVs treatment reduced viability, increased apoptosis levels associated with a decrease in B-cell lymphoma 2 protein expression and reduced mitochondrial membrane potential. Interestingly, the effects observed with MOES MVs treatment were comparable to those observed with MOES treatment and transfection with the pool of small RNAs isolated from MOES, used as a control. These results highlight the role of microRNAs transported by MOES MVs as natural bioactive plant compounds that counteract tumorigenesis.

Phytochemical Profile and Biological Properties of Colchicum triphyllum (Meadow Saffron)

In this work, the phytochemical profile and the biological properties of Colchicum triphyllum (an unexplored Turkish cultivar belonging to Colchicaceae) have been comprehensively investigated for the first time. Herein, we focused on the evaluation of the in vitro antioxidant and enzyme inhibitory effects of flower, tuber, and leaf extracts, obtained using different extraction methods, namely maceration (both aqueous and methanolic), infusion, and Soxhlet. Besides, the complete phenolic and alkaloid untargeted metabolomic profiling of the different extracts was investigated. In this regard, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) allowed us to putatively annotate 285 compounds when considering the different matrix extracts, including mainly alkaloids, flavonoids, lignans, phenolic acids, and tyrosol equivalents. The most abundant polyphenols were flavonoids (119 compounds), while colchicine, demecolcine, and lumicolchicine isomers were some of the most widespread alkaloids in each extract analyzed. In addition, our findings showed that C. triphyllum tuber extracts were a superior source of both total alkaloids and total polyphenols, being on average 2.89 and 10.41 mg/g, respectively. Multivariate statistics following metabolomics allowed for the detection of those compounds most affected by the different extraction methods. Overall, C. triphyllum leaf extracts showed a strong in vitro antioxidant capacity, in terms of cupric reducing antioxidant power (CUPRAC; on average 96.45 mg Trolox Equivalents (TE)/g) and ferric reducing antioxidant power (FRAP) reducing power (on average 66.86 mg TE/g). Interestingly, each C. triphyllum methanolic extract analyzed (i.e., from tuber, leaf, and flower) was active against the tyrosinase in terms of inhibition, recording the higher values for methanolic macerated leaves (i.e., 125.78 mg kojic acid equivalent (KAE)/g). On the other hand, moderate inhibitory activities were observed against AChE and α-amylase. Strong correlations (p < 0.01) were also observed between the phytochemical profiles and the biological activities determined. Therefore, our findings highlighted, for the first time, the potential of C. triphhyllum extracts in food and pharmaceutical applications.

Impact of Ultrasound Extraction Parameters on the Antioxidant Properties of Moringa Oleifera Leaves

Recently, much interest has been focused on Moringa oleifera L., a highly versatile and sustainable plant. In addition to its nutritional properties, numerous bioactive compounds have been identified in M. oleifera leaves, for which healthy properties have been reported. In the present research, the impact of ultrasound-assisted extraction (UAE) on the recovery of the bioactive compounds from leaves was investigated. Firstly, an experimental design approach has been used to highlight the influence of some extraction parameters (solvent, solvent/dry leaves ratio, temperature, time) on phenol compound recovery and antioxidant activity. Solvent composition was the most influential factor; in fact, the presence of water in the solvent (50:50, v/v) corresponded to an increase in the extraction performance. The liquid/solid ratio (L/S) also influenced the extraction process; in fact, the total phenol content reached 13.4 mg gallic acid equivalent (GAE)/g dry matter (DM) in the following UAE conditions: 50% water, 60:1 L/S ratio, 60 °C, 60 min. In order to quantify flavonols, hydroalcoholic extracts were analysed by HPLC-DAD (high performance liquid chromatography-diode array detector). In the flavonol class, the glycosidic forms of quercetin and kaempferol were mainly detected. Their content ranged from 216.4 µg/g DM of quercetin 3-O-rhamnoside to 293.9 µg/g DM of quercetin 3-O-(6″-O-malonyl)-β-D-glucoside. In summary, the leaves of M. oleifera are a potential natural source of bioactive compounds, proving to be very promising for the development of health-promoting food supplements.

Mo-HLPs: New flocculating agents identified from Moringa oleifera seeds belong to the hevein-like peptide family

Cationic peptides found in Moringa oleifera seeds belong to different protein families and are described as the main flocculating agents of the species. In this study we report the identification and isolation of four new flocculant peptides, called Mo-HLPs 1-4, belonging to the family of hevein-like peptides, previously only known for their members' antimicrobial activity. Purification of the peptides followed two sequential membrane ultrafiltration steps and separation by reverse-phase liquid chromatography. Proteomic analyses showed that Mo-HLPs are extremely basic (pI >10) cysteine-rich molecules with molecular masses between 4.5 and 4.8 kDa and with a highly conserved chitin-binding domain. Searches in BLAST revealed high similarity of Mo-HLPs with hevein and other hevein-like peptides and 90% identity with morintides, which are members of the 8C-hevein-like subfamily found in M. oleifera leaves. Mo-HLPs microflocculation assays showed distinct coagulation/flocculation efficiencies, promoting turbidity reduction levels between 67 and 89% in synthetic turbid water. Activity variations were attributed to the substitution of some amino acids among the isoforms, which may have altered the final net charge of the molecules. The identification of Mo-HLPs represents the discovery of a new group of cationic peptides involved in the flocculation properties of M. oleifera seeds. SIGNIFICANCE: The study reveals the presence of hevein-like peptides in Moringa oleifera seeds. It is reported for the first time that members of this family have properties to act as flocculating agents of importance for water treatment processes. The identification of these peptides as well as new functional assignment broadens the horizon for speculation on new species which could act as sources of green coagulants for sustainable water treatment, and contributes to the knowledge about occurrence, distribution, molecular and active diversity of peptides belonging to the hevein-like family.

Enzyme Inhibition and Antimicrobial Activities of Fractionated Wild Grape (Ampelocissus martinii Planch.) Seed Extracts

BACKGROUND AND OBJECTIVE

Study on medicinal plant extract is gradually interested and distributed, especially their biological activities. The present study aimed to determine the enzyme inhibition and antimicrobial activities of the fractionated extracts of wild grape (Ampelocissus martinii Planch.) seeds.

MATERIALS AND METHODS

Wild grape seeds in different growth stages were extracted with methanol before fractionation by silica gel chromatography. The anti-glucosidase and anti-tyrosinase enzyme activities of the extracts were then tested by using UV-Vis spectrophotometry and antimicrobial activities were observed from MIC, MBC values and time killing assay.

RESULTS

The sub-fraction of immature stage eluted by ethyl acetate/methanol at 75/25 (%v/v) has the highest enzyme inhibition activity and the most potent efficiency for time kills profiles. The MIC values of the potent immature, mature and ripe fractioned extracts were ranging from 1.25-50.00, 1.25-50.00 and 1.56-25.00 mg mL-1, respectively, while the MBC values ranged from 3.12-6.25, 3.12-25.00 and 3.12-25.00 mg mL-1, respectively.

CONCLUSION

The wild grape seed composed of α-glucosidase and tyrosinase inhibition and antibacterial activities compounds. The wild grape seed extracts may be used as active ingredients sources of health-supporting products or cosmetics.

The Effect of Ultrasonication Pretreatment on the Production of Polyphenol-Enriched Extracts from Moringa oleifera L. (Drumstick Tree) Using a Novel Bio-Based Deep Eutectic Solvent

Moringa oleifera L. leaves are a plant tissue particularly rich in polyphenolic phytochemicals with significant bioactivities, and there has been significant recent interest for the production of extracts enriched in these substances. The current investigation is aimed at establishing a green extraction process, using a novel eco-friendly natural deep eutectic solvent, composed of glycerol and nicotinamide. Furthermore, sample ultrasonication prior to batch stirred-tank extraction was studied to examine its usefulness as a pretreatment step. Optimization of the extraction process through response surface methodology showed that the maximum total polyphenol yield (82.87 ± 4.28 mg gallic acid equivalents g−1 dry mass) could be achieved after a 30 min ultrasonication pretreatment, but the difference with the yield obtained from the non-pretreated sample was statistically non-significant (p < 0.05). Extraction kinetics revealed that the activation energy for the ultrasonication-pretreated samples was more energy-demanding, a fact attributed to phenomena pertaining to washing of the readily extracted polyphenols during pretreatment. Liquid-chromatography-diode array-mass spectrometry showed that ultrasonication pretreatment may have a limited positive effect on polyphenol extractability, but the overall polyphenolic profile was identical for the ultrasonication-pretreated and non-pretreated samples.

Optimization of Phenolic Compound Extraction from Chinese Moringa oleifera Leaves and Antioxidant Activities

Rich in phenolic compounds, Moringa oleifera leaf extract (ME) exhibits significant antioxidant activity both in vitro and in vivo. ME has already been widely used in fields of medicine, functional food, and cosmetics. Ultrasonic extraction (UE) method has been improved to be one of the most effective ways to extract phenols from M. oleifera leaves. The purpose of this study was to optimize ultrasonic extraction of phenols by response surface methodology (RSM). Four parameters were discussed, such as ethanol concentration, solvent-sample ratio, extraction temperature, and extraction time. Also, purification methods of the crude ME by organic solvent extraction and column chromatography were examined. Antioxidant activities of ME and each fraction were evaluated by DPPH, ABTS, and hydroxy radical-scavenging activities and reducing power. The phenol content of the purified ME reached up to 962.6 mg RE/g, extremely higher than the crude extract 107.22 ± 1.93 mg RE/g. The antioxidant activity of the purified ME was also significantly improved. Furthermore, phenols were identified by using the HPLC-MS method, and the results showed that there were 6 phenolic acids and derivatives and 7 flavonoids in ME. Quercetin-3-O-β-D-glucoside isolated from ME showed excellent DPPH and ABTS radical-scavenging abilities, which were comparable to VC.

Comparative study of flocculation and adsorption behaviour of water treatment proteins from Moringa peregrina and Moringa oleifera seeds

Trees of Moringa oleifera are the most widely exploited species of Moringa and proteins extracted from its seeds have been identified as the most efficient natural coagulant for water purification. Largely for climatic reasons, other Moringa species are more accessible in some regions and this paper presents a comparative study of the adsorption to different materials of the proteins extracted from seeds of Moringa peregrina and Moringa oleifera to explore their use as flocculating agents in regions where each is more readily accessible. Results showed that Moringa peregrina seed proteins had higher adsorption to alumina compared to silica, in contrast to opposite behavior for Moringa oleifera. Both species provide cationic proteins that can act as effective coagulants for the various impurities with different surface potential. Despite the considerable similarity of the amino acid composition, the seed proteins have significantly different adsorption and this presents the opportunity to improve processes by choosing the optimal species or combination of species depending on the type of impurity or possible development of separation processes.

First Report on Evaluation of Basic Nutritional and Antioxidant Properties of Moringa Oleifera Lam. from Caribbean Island of Saint Lucia

Moringa oleifera Lam. has been considered as a multipurpose tree. The studies on it focus on its variable nutritional benefits. It is growing in many regions, but information about nutritional properties of those growing in the Caribbean is missing. The present study focused on biochemical analysis of main nutritional and antioxidant properties in plant material-dried leaves and seeds-of Moringa oleifera. The composition of lipids, proteins, and vitamin E was evaluated in powdered dried leaves and seeds. Fatty acids were evaluated in oil extracted from the moringa seeds. Potential antioxidant properties of the moringa were evaluated in extract from crushed and powdered leaves, as well as from the powdered seeds. The total amounts of lipids, proteins, and vitamin E were higher in powdered seeds (31.85%, 35.13%, and 220.61 mg/kg) than in powdered leaves (12.48%, 20.54%, and 178.10 mg/kg). The main compound of fatty acids presented oleic acid (76.78%) in seeds' oil and oleic (25.01%), palmitic (24.84%), and linolenic (24.71%) acids in leaves. Neohesperidin (126.8 mg/kg), followed by chlorogenic acid (99.96 mg/kg) and quercetin (43.44 and 21.44 mg/kg) were main phenolic compounds identified. Total phenols in powdered leaves' extract (635.6 mg GAE/L) was higher than in powdered seeds' extract (229.5 mg GAE/L). The activity against superoxide radical and hydroxyl radical was 92.4% and 73.1% by leaves' powder extract and 83.6% and 60.7% by crushed-leaf extract; seed-powder extract exhibited a pro-oxidation activity (-68.4%) against superoxide radical and the lowest antioxidant effect against the hydroxyl radical (55.0%).

Bioguided extraction of phenolic compounds and UHPLC-ESI-Q-TOF-MS/MS characterization of extracts of Moringa oleifera leaves collected in Brazil

Moringa oleifera leaves are used in Brazilian folk medicine for their hypoglycemic and nutritional properties. In this context, the chemical and biological characteristics were determined. Conventional successive solid-liquid extraction with simultaneous bioguided purification using solvents with different polarities was performed with M. oleifera leaves, yielding six fractions and extracts. The fractions showed better results for antioxidant activity than the extracts. All of them were evaluated by scavenging of synthetic free radicals and reactive oxygen species, and Fr-Ace and Fr-EtOAc showed >100 mg GAE g^-1 of phenolic content, while for FRAP and ORAC assays the values were higher than 1600 μmol Fe²⁺ g^-1 and 3500 mmol TEAC g^-1 respectively. The UPLC-ESI-QTOF-MS analysis of hydroalcoholic extract (HE) allowed identifying 24 compounds, with flavonoid derivatives being the most abundant group. Furthermore, the alkaloid trigonelline and sesquiterpenoid abscisic acid were identified for the first time in M. oleifera leaves. Finally, gallic acid, caffeic acid, rutin and quercetin were found in concentrations of 16.5, 2129, 477.4 and 127.5 μg g^-1 respectively in HE, all of which were higher in fractions and extracts. These results suggest that bioguided extraction is an important technique, due to its ability to concentrate active compounds in a logical and rational way. In addition, M. oleifera leaves grown in Brazil are an important source of phenolic compounds with antioxidant activity that can be used in food, nutraceutical and pharmaceutical products.

Structural diversity, biosynthetic aspects, and LC-HRMS data compilation for the identification of bioactive compounds of Lepidium meyenii

Lepidium meyenii is widely used as a food supplement because of its medicinal properties and nutritional value. Several studies have described the identification of its metabolites and LC-HRMS analysis is one of the most frequently used analytical tool to assess plant extract metabolome. Nevertheless, proper and reliable metabolite identification is essential for such metabolomics studies. Although HRMS distinguishes even minor changes in the metabolites structures, highly specialized secondary metabolites might not be present on available databases imposing serious obstacles for metabolite identification This review discusses the structural diversity and biosynthetic aspects of 101 compounds previously identified in L. meyenii. More importantly, we have compiled the available information on expected and experimental high-resolution masses of L. meyenii compounds. This will help upcoming metabolomics studies not only of L. meyenii but also other plant species by providing the necessary tools to perform proper and reliable identification of their bioactive compounds.

Consumption of Moringa oleifera Lam Leaves Lowers Postprandial Blood Pressure

Objective: This clinical study monitored the effect of eating cooked Moringa oleifera leaves on the blood pressure (BP) of healthy participants in view of the perception that consumption of Moringa is associated with an increase in blood pressure, which is contradictory to the findings from the literature.Methods: A random sample of 41 healthy participants were enrolled in this prospective, placebo-controlled clinical study. Participants in the case study consumed 120 g of cooked M. oleifera leaves while the control group did not eat Moringa leaves. BP was measured at baseline before the meal and followed up at regular intervals over 24 hours for both groups. Baseline (T0) mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) and postprandial follow-up (T2-T24) were measured for both groups. Participants recorded their diet for a week and this led to an estimation of the total salt consumption per day.Results: A significant difference was observed between DBP at baseline and two hours postprandial (T2) for the case group (p = 0.013). Moreover, in the case group, despite high consumption of salt (7 g/d) during the week preceding the clinical study, there was a significant decrease in both the SBP and DBP. In the control group, participants with prior high consumption of salt (7 g/d) during the week had elevated SBP and DBP.Conclusions: These findings in human subjects indicated the lowering effect of Moringa oleifera leaves consumption on the 2 hours postprandial BP and showed a potential lowering effect on both SBP and DBP despite prior high consumption of salt (7 g/d).

Bioaccessibility, antioxidant activity and modulation effect on gut microbiota of bioactive compounds from Moringa oleifera Lam. leaves during digestion and fermentation in vitro

This study aims to investigate the bioaccessibility, bioactivity and gut microbiota modulation effect of Moringa oleifera Lam. leaves after in vitro gastrointestinal digestion and colonic fermentation.

Impact of conventional/non-conventional extraction methods on the untargeted phenolic profile of Moringa oleifera leaves

The impact of different extraction methods, namely maceration, homogenizer-assisted extraction, rapid solid-liquid dynamic extraction, microwave-assisted extraction and ultrasound-assisted extraction, on polyphenols of Moringa oleifera leaves was studied. The phenolic composition of alcoholic (methanol 100%) and hydroalcoholic (methanol/water 50:50, v/v) extracts was compared by using an untargeted metabolomics-based profiling approach followed by multivariate statistics. With this aim, ultra-high-pressure liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometry was used to profile phenolic compounds under the different extraction conditions. Besides, the in vitro antioxidant activities of Moringa leaves were also investigated as ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). The metabolomic approach allowed to putatively annotate 262 phenolic compounds. In particular, glycosidic forms of quercetin (i.e., quercetin 3-O-galactoside, quercetin 3-O-glucoside, and quercetin 4'-O-glucoside) were the most represented compounds among flavonoids. Furthermore, protocatechuic acid was found to be the most abundant hydroxybenzaldheyde derivative, while the isomeric forms of hydroxybenzoic acid characterized the phenolic acids class. Overall, the extractions in methanol 100% were found to be the most effective for phenolic compounds recovering, when compared with those in methanol/water (50:50, v/v). Homogenizer-assisted extraction of M. oleifera leaves using 100% methanol allowed extracting the highest amounts of polyphenols (35.19 mg/g) and produced the highest oxygen radical absorbance capacity (536.27 μmol Trolox Equivalents/g). The supervised orthogonal projection to latent structures discriminant analysis identified phenolic acids as the phenolic class mostly affected by the different extraction technologies. These findings demonstrate that each extraction method promoted the recovery of specific phenolic subclasses with different efficiencies.