Blanching influences the phenolics composition, antioxidant activity, and inhibitory effect of Adansonia digitata leaves extract on α-amylase, α-glucosidase, and aldose reductase

Influence of Blanching Time on the Phytochemical and Nutritive Value of Cowpea (Vigna unguiculata L. Walp) Leafy Vegetable

Seasonal production limits the effective utilization of cowpea, which is regarded as food and a cash income crop in most African rural communities. To reduce the bacterial content and inactivate the naturally occurring enzymes that could induce undesirable changes during storage of the vegetable, blanching is applied. However, loss in flavor and nutritional value is experienced. Therefore, a study was conducted to investigate the effects of different blanching times on cowpea at a constant temperature, on its nutritive value. A 2 kg sample of fresh leaves was divided into four portions and blanched at 95°C for 0 (control), 2.5, 5, and 10 min. The study was arranged in a completely randomized design in triplicate. Collected data included moisture, total phenolic, antioxidant activity, and minerals [calcium (Ca), potassium (K), cobalt (Co), chromium (Cr), and silicon (Si)]. Compared to the control, total phenolic increased at 2.5 min to 9.83 mg GAE/g but then decreased by 4.99 and 4.60 mg GAE/g at 5 and 10 min of blanching time, respectively. Similarly, antioxidant activity increased at 2.5 min to 1025 μg AAE/g of WM, but reduced by 751.71 and 641.80 μg AAE/g of WM at 5 and 10 min, respectively. Ca increased at 2.5, 5, and 10 min by 69.10, 62.47, and 74.53 mg/L, respectively. Similarly, K increased at 2.5, 5, and 10 min by 31.57, 49.13, and 46.03 mg/L, respectively. Contrarily, Co decreased by 7.65, 7.37, and 9.29 mg/L at 2.5, 5, and 10 min of blanching, respectively. Similarly, Cr also decreased at 2.5, 5, and 10 min, by 0.23, 0.35, and 0.56 mg/L, respectively. Si increased at 2.5 and 10 min by 4.15 and 3.31 mg/L and reduced at 5 min by 1.61 mg/L. Therefore, blanching time of 2.5 min at a constant temperature of 95°C increased the tested nutritive elements, except for moisture, Co, and Cr.

Influence of industrial blanching, cutting, and freezing treatments on in vitro gastrointestinal digestion stability of orange (Citrus sinensis L.) and lemon (Citrus limon L.) peel polyphenols

BACKGROUND

Citrus peels, which are often discarded as waste in the food-processing industry, are rich sources of polyphenols. The aim of the current study was to investigate the influence of an industrial freezing process along with blanching and cutting pretreatments on the in vitro gastrointestinal digestion stability of orange (Citrus sinensis L.) and lemon (Citrus limon L.) peel polyphenols. The major polyphenols were identified and quantified with ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) and high performance liquid chromatography-photodiode array detector (HPLC-PDA), respectively.

RESULTS

The results revealed that hesperidin and chlorogenic acid were the predominant flavonoid and phenolic acids in orange peels whereas, for lemon peels, eriocitrin and caffeic acid were the dominant flavonoid and phenolic acids, respectively. Blanching pretreatment enhanced the levels of major flavonoids in orange and lemon peels (by 39-82% and 54-146%, respectively) (P < 0.05) after in vitro gastrointestinal digestion. On the other hand, the application of cutting treatment after blanching significantly reduced the levels of flavonoids (23-62%) (P < 0.05); however, there was no statistically significant difference between the phenolic acid levels of cut and uncut citrus peels. Overall, the bioaccessibility of individual flavonoids and phenolic acids from frozen orange peels was generally slightly lower than that of untreated peels (9-34% and 9-49%, respectively). Nevertheless, frozen lemon peels contained higher bioaccessible flavonoids and phenolic acids in comparison with untreated peels (40-172% and 32-98%, respectively).

CONCLUSION

These results suggest that industrial freezing steps could largely preserve the bioaccessibility of polyphenols in orange and lemon peels. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Influence of convective hot air drying on physico-functional, thermo-pasting and antioxidant properties of elephant foot yam powder (Amorphophallus paeoniifolius)

The present study focused on the effect of different drying temperatures (40, 50, 60 and 70 °C) and combination of pre-treatments: potassium metabisulphite (KMS), potassium metabisulphite + Citric acid + blanching (KCB)] on functional, thermo-pasting and antioxidant properties of elephant foot yam (EFY) powder. Drying temperature and pretreatment reduces the water and oil absorption capacity, and the highest values were 2.34 g/g and 1.19 g/g for drying at 40 °C for the untreated sample, respectively. KMS pretreatment enhanced the bulk density, foaming capacity, emulsion capacity, and emulsion stability with an increase in drying temperature. Pasting temperature and viscosity decreased with an increase in drying temperature, and the maximum was observed at 40 °C for KMS pretreatment. Blanching increases the gelatinization temperature resulting in higher mid-and end-temperatures for KCB pretreatment. The antioxidant properties decreased with an increase in the drying temperature and were found to be minimal in the case of KCB treated samples.

Nutritional, Physicochemical, Microstructural, Rheological, and Organoleptical Characteristics of Ice Cream Incorporating Adansonia digitata Pulp Flour

Ice cream's appeal is unrivaled. Nonmilk and milk ingredients in ice cream formulas affect their nutritional value, structure, and organoleptical qualities. Seeking novel dietary ingredients instead of artificial flavoring compounds is vital for improving ice cream taste preference, adding antioxidants, and increasing nutritional value. The current study examines the feasibility of manufacturing a new flavored ice cream with excellent dietary value using Adansonia digitata L. (Baobab) fruit pulp (ADFP). The prepared ice cream's physicochemical and microbiological quality, and rheological, microstructural, and organoleptic properties were investigated. Using ADFP instead of skim milk powder with a partial or complete replacement, five ice cream samples were produced and marked as IB-0, IB-25, IB-50, IB-75, and IB-100. Chemical characteristics were not noticeably impacted except protein and ash, which considerably decreased with increasing ADFP levels. Increasing ADFP in the samples increased titratable acidity and reduced pH. All ice cream samples were microbiologically acceptable with no pathogenic bacteria. By increasing ADFP in the samples, the daily values (%DV) of sodium, potassium, and magnesium were not considerably affected. Calcium reduced from 14.91% in IB-0 to 7.75% in IB-100. All microelements found in the study rose considerably as ADFP increased. Increasing ADFP levels significantly boosted antioxidant levels. The IB-100 sample had the highest total phenolic content (149.29 mg GAE 100 g^-1), antioxidant activity (98.12 µmol of TE 100 g^-1), total flavonoids (5.96 mg QE 100 g^-1), and total flavanols (4.01 mg QE 100 g^-1). The inclusion of ADFP had a beneficial effect on the color of the samples. It did not negatively affect the ice cream's organoleptic acceptability as determined by organoleptic, rheological, and microstructural examinations. Interestingly, when skim milk powder was replaced with 50% and 75%, the hardness, viscosity, and aqueous phase separation were significantly improved. In conclusion, ADPF improves the nutritional value of ice cream and can be used as a natural coloring ingredient without affecting microstructural and rheological properties.

Telfairia occidentalis stimulates hepatic glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms

Background

Telfairia occidentalis (TO), a plant consumed for its nutritional and medicinal values, exhibits hypoglycaemic effect. However, the metabolic fate of the glucose following TO-induced insulin secretion and consequent hypoglycaemia is not clear.

Objective

This study determined the effect of ethyl acetate and n-hexane fractions of TO leaf extracts on some biochemical parameters in the glucose metabolic pathway to explain the possible fate of blood glucose following TO-induced hypoglycaemia.

Methods

Eighteen male Wistar rats (180-200 g) divided into control, n-hexane TO fraction- and ethyl acetate TO fraction-treated groups (n = 6/group) were used. The control animals received normal saline while the treated groups received TO at 100 mg/kg for seven days. After 24 h following the last dose, the animals were anaesthetised using ketamine; blood samples were collected and livers harvested to determine some biochemical parameters.

Results

Ethyl acetate TO fraction significantly increased plasma insulin, liver glucokinase activity and plasma pyruvate concentration, but significantly decreased plasma glucose and liver glycogen, without significant changes in plasma lactate, glucose-6-phosphate, liver glucose-6-phosphatase and lactate dehydrogenase activities when compared with control. N-hexane TO fraction significantly reduced liver glucose-6-phosphatase activity and glycogen but significantly increased plasma pyruvate, without significant changes in plasma glucose, insulin, glucose-6-phosphate and lactate concentrations; and liver glucokinase and lactate dehydrogenase activities.

Conclusion

The present study showed that insulin-mediated TO-induced hypoglycaemia resulted in the stimulation of glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms.

Systematics, Phytochemistry, Biological Activities and Health Promoting Effects of the Plants from the Subfamily Bombacoideae (Family Malvaceae)

Plants belonging to the subfamily Bombacoideae (family Malvaceae) consist of about 304 species, many of them having high economical and medicinal properties. In the past, this plant group was put under Bombacaceae; however, modern molecular and phytochemical findings supported the group as a subfamily of Malvaceae. A detailed search on the number of publications related to the Bombacoideae subfamily was carried out in databases like PubMed and Science Direct using various keywords. Most of the plants in the group are perennial tall trees usually with swollen tree trunks, brightly colored flowers, and large branches. Various plant parts ranging from leaves to seeds to stems of several species are also used as food and fibers in many countries. Members of Bombacoides are used as ornamentals and economic utilities, various plants are used in traditional medication systems for their anti-inflammatory, astringent, stimulant, antipyretic, microbial, analgesic, and diuretic effects. Several phytochemicals, both polar and non-polar compounds, have been detected in this plant group supporting evidence of their medicinal and nutritional uses. The present review provides comprehensive taxonomic, ethno-pharmacological, economic, food and phytochemical properties of the subfamily Bombacoideae.

Nutritional and Rheological Characteristics of Composite Flour Substituted with Baobab (Adansonia digitata L.) Pulp Flour for Cake Manufacturing and Organoleptic Properties of Their Prepared Cakes

Revalorization of Adansonia digitata L. "Baobab" pulp flour (BPF) to produce a notorious and functional cake in the current study was assessed. Wheat flour (WF 72%) was partially substituted by BPF at 5, 10, and 15% to prepare composite flour (WF + BPF) for potential cake manufacturing. Approximate chemical composition, macro- and microelements content, amino acids (AAs), total phenolic content (TPC), and antioxidant activity (AOA) of partially substituted composite flour (WF + BPF) were determined. The rheological properties of the composite flours were assessed using MIXOLAB. Moreover, an organoleptic evaluation of the baked cakes was performed with 20 trained panelists. The substitution with BPF significantly increased the total ash and crude fiber content in composite flour in a level-dependent manner, while moisture, crude fat, crude protein, available carbohydrates contents, and energy values were not significantly changed. Interestingly, macroelements such as Ca, K, and P were significantly increased, while Na was significantly decreased, whereas Mg content was not significantly changed. Similarly, microelements such as Zn, Fe, and Cu increased with the increase of BPF substitution. Significant increases in TPC and AOA were found by increasing the substitution with BPF. The biological value (BV), essential amino acid index (EAAI), protein efficiency ratio (PER), as well as essential amino acids (EAAs) requirement index (RI) were positively improved in WF + BPF. Adding BPF up to 10% not only improved the water absorption, α-amylase activity, and viscosity, but also caused a slight weakness in the gluten network, to produce a composite flour suitable for cake making. Conclusively, this study revealed that fortification with BPF up to 5-10% improved the nutritional quality without adverse effects on technological, and organoleptic characteristics and providing economic, commercial, and health benefits.

Bioactive Composition and Free Radical Scavenging Activity of Fresh Orange Maize Hybrids: Impacts of Genotype, Maturity Stages, and Processing Methods

Bioactive compounds in foods are responsible for their biological activities, but biotic and abiotic factors may influence their levels. This study evaluated the impact of three genotypes (designated 4, 5, and 7), maturity stages (20, 27, and 34 days after pollination) and processing methods (hydrothermal and dry-heating) on the bioactive constituents (carotenoids, phytate, tannins, vitamin C) and 2,2-diphenyl-2-picrylhydrazyl radical (DPPH^*) scavenging activity of fresh orange maize hybrids. Freshly harvested maize cobs of each genotype were subjected to hydrothermal processing at 100°C and dry-heating with husks and without husks. Carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and total β-carotene) contents of fresh and processed samples were analyzed using HPLC; other bioactive constituents and DPPH^* scavenging ability were determined using spectrophotometric methods. Genotype had a significant effect on the levels of carotenoids (p < 0.001) and vitamin C (p < 0.05), while genotype (p < 0.001), and processing methods (p < 0.001) had significant effects on DPPH^* SC₅₀. Maturity stages, processing methods and their interaction also had significant effects (p < 0.001) on the levels of all the bioactive constituents. A positive moderate to strong correlation was observed between (p < 0.001) α-carotene and the following: lutein (r = 0.57), β-cryptoxanthin (r = 0.69), total β-carotene (r = 0.62). However, the relationship between α-carotene and zeaxanthin was positive but weak (r = 0.39). A positive moderate correlation (p < 0.001) was observed between lutein and the following: β-cryptoxanthin (r = 0.57), total β-carotene (r = 0.58), and zeaxanthin (r = 0.52). A positive strong correlation (p < 0.001) was observed between β-cryptoxanthin and each of total β-carotene (r = 0.92) and zeaxanthin (r = 0.63); total β-carotene and zeaxanthin (r = 0.65); while the association between vitamin C and DPPH^* SC₅₀ was negative and weak (r = −0.38). Generally, genotype 4 and harvesting at 34 days after pollination had the best combination of bioactive constituents and DPPH^* scavenging ability.

In Vitro Evaluation of Anti-Rift Valley Fever Virus, Antioxidant and Anti-Inflammatory Activity of South African Medicinal Plant Extracts

Rift valley fever virus (RVFV) is a mosquito-borne virus endemic to sub-Saharan African countries, and the first sporadic outbreaks outside Africa were reported in the Asia-Pacific region. There are no approved therapeutic agents available for RVFV; however, finding an effective antiviral agent against RVFV is important. This study aimed to evaluate the antiviral, antioxidant and anti-inflammatory activity of medicinal plant extracts. Twenty medicinal plants were screened for their anti-RVFV activity using the cytopathic effect (CPE) reduction method. The cytotoxicity assessment of the extracts was done before antiviral screening using the MTT assay. Antioxidant and reactive oxygen/nitrogen species' (ROS/RNS) inhibitory activity by the extracts was investigated using non-cell-based and cell-based assays. Out of twenty plant extracts tested, eight showed significant potency against RVFV indicated by a decrease in tissue culture infectious dose (TCID50) < 105. The cytotoxicity of extracts showed inhibitory concentrations values (IC50) > 200 µg/mL for most of the extracts. The antioxidant activity and anti-inflammatory results revealed that extracts scavenged free radicals exhibiting an IC50 range of 4.12-20.41 µg/mL and suppressed the production of pro-inflammatory mediators by 60-80% in Vero cells. This study demonstrated the ability of the extracts to lower RVFV viral load and their potency to reduce free radicals.

Assessment of the phytochemical, antioxidant and antibacterial activities of Heteromorpha arborescens (Spreng.) Cham & Schltdl. leaf extracts

Background: Heteromorpha arborescens (Spreng.) Cham. and Schltdl (Apiaceae) is widely used traditionally for the treatment of a wide range of diseases in Southern and Eastern Africa. Although previous studies have reported the biological activities of hexane, ethyl acetate and methanol extracts of H. arborescens leaves, there is no scientific information on the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts. This study is therefore aimed to investigate and compare the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts of H. arborescens leaves. Methods: Phytochemical analysis for the total phenolic, flavonoid, proanthocyanidin, alkaloid and saponin contents of all the fractions were determined by spectroscopic methods, while the free radical scavenging potential of the extracts were evaluated using DPPH, ABTS radical scavenging and total antioxidant capacity assays. Micro dilution method was used to determine the Minimum Inhibitory Concentrations (MIC) of H. arborescens leaf extracts against Bacillus pumilus, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Results: Total phenol content of the extracts ranged between 15.10 mg GAE/g- 42.50 mg GAE/g, proanthocyanidin was 459-8402.1 mg QE/g, and flavonoid content of 109.24-235.79 mg QE/g. In addition, alkaloids (5.59%) and saponins (23.33%) were present in significant amounts. Based on the IC ₅₀ values, the ethanol extract exhibited the highest total antioxidant activity (0.013 mg/mL) with highest inhibition against DPPH and ABTS radicals (0.06 and 0.049 mg/mL respectively). Considerable antibacterial activities were observed in the acetone, ethanol and blanched extracts with MIC values ranging from 1.563-12.5 mg/mL; however, the aqueous extract was inactive against all the bacteria strains. Conclusion: The study suggests that H. arborescens leaves could be a valuable source of bioactive compounds. Although the blanching process significantly decreased polyphenolic contents and antioxidant activities of the extracts, it increased the antibacterial compounds.

Hydromethanolic Extracts from Adansonia digitata L. Edible Parts Positively Modulate Pathophysiological Mechanisms Related to the Metabolic Syndrome

Metabolic syndrome includes a cluster of risk factors for many pathological conditions, including hyperglycemia, abdominal obesity, hyperlipidemia, and hypertension. Adansonia digitata L. (also known as baobab) is used in traditional African Medicine and recent studies showed that it improves the metabolism of carbohydrates and lipids. The aim of this study is to investigate the mechanisms of action associated with the beneficial effects of extracts from the edible parts of baobab (fruit pulp, leaves, raw and toasted seeds), evaluating their inhibitory activity against: alpha-amylase, alpha-glucosidase, angiotensin-converting enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and pancreatic lipase. Baobab fruit pulp and leaf extracts resulted to be the most active ones and were then tested on the differentiation process of SW-872 human liposarcoma cells to mature adipocytes. The addition of these latter extracts did not affect triglyceride accumulation, indicating a neutral impact on this parameter. The findings here reported help to explain the growing amount of evidence on the biological properties of baobab and provide suggestions about their use in food and nutraceutical fields.

Unravelling the Biological Potential of Pinus pinaster Bark Extracts

Natural compounds from agro-food by-products have fostered interest in food industries. The aim of this study was to unravel potential uses for Pinus pinaster bark extracts (PBE). As functional features of this type of extracts are usually attributed to phenolic compounds, the extraction process was studied. Different PBEs were achieved, with high content in phenolic compounds, using different water/ethanol combinations as a solvent. These PBEs were chemically characterized, and their bioactivity and in vitro cell viability were evaluated. Extracts obtained with hydroethanolic solvents had higher content in phenolic and flavonoid compounds. All the PBEs presented high antioxidant, antibacterial and antihyperglycemic activities. Moreover, PBEs have low cytotoxicity and a selective activity against cancer cells as these were negatively affected. These features may allow the extracts to be used in food formulation and processing (as preservatives, antioxidants or bioactive ingredients), but they showed also potential for the pharmaceutical or nutraceutical sectors.

HPLC-QTOF-MS/MS profiling, antioxidant, and α-glucosidase inhibitory activities of Pyracantha fortuneana fruit extracts

This study was carried out to optimize the solvent for extracting the antioxidants and α-glucosidase inhibitors (AGIs) from Pyracantha fortuneana fruit (PFF) and the major chemical components were characterized by HPLC-QTOF-MS/MS. The results showed that 50% and 70% acetone (v/v, ml/ml) gave the best extraction efficiency on phenolics and total flavonoids, while 70% acetone and 50% methanol possess better recovery on protein and polysaccharides, respectively. In addition, the 50% and 70% acetone extracts gave the strongest radical scavenging ability and α-glucosidase inhibitory activity (p > 0.05), but the Fe³⁺ reducing power of the 50% acetone extract was higher than that of 70% acetone. Correlation analysis indicated that phenolic acids and flavonoids were connected to the antioxidant activity and α-glucosidase inhibitory activity closely. Moreover, 25 compounds including 7 flavonoids, 6 phenolic acids, 7 organic acids, 3 tannins, 1 terpene, and 1 alkaloid were identified or tentatively identified in the 50% acetone extract. Overall, 50% acetone can be a proper solvent for extracting antioxidants and AGIs from PFF. PRACTICAL APPLICATIONS: Imbalance between production and clearance of reactive oxygen species (ROS) in the body could induce various chronic diseases. PFF is an edible fruit beneficial to human health; it is reported to be capable of optimizing blood glucose levels and may prevent premature aging. In the present study, PFF was found to be excellent in antioxidant activities and α-glucosidase inhibitory ability; 50% acetone was found to be the best extraction solvent. In addition, the predominant phytochemical components of the 50% acetone extract were characterized. This study can promote further research of Pyracantha fortuneana in natural functional products, especially in the prevention of type II diabetes and its complication.

Chemical analysis and evaluation of antioxidant and antimicrobial activities of fruit fractions of Mauritia flexuosa L. f. (Arecaceae)

Background

Fruit consumption is currently considered beyond the nutritional aspects because of the important roles in disease prevention and benefits to health. The objective of this study was to characterize the chemical profile and evaluate the antioxidant and antimicrobial properties of different fractions obtained from fruit pulps of Mauritia flexuosa (MFFs).

Methods

Initially, chloroform, ethyl acetate and ethanol fractions were obtained from the pulps. Quantifications of total phenols and flavonoids were performed using the methods of Folin-Ciocalteu and complexation with aluminum chloride, respectively. Standard samples were used to identify and quantify phenolic acids and flavonoids using high-performance liquid chromatography with a diode-array detector (HPLC-DAD). The antioxidant capacity of the fractions was verified by sequestration of the free radical 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and iron chelating activity. The antimicrobial activity was determined using the microdilution method and the modulating activity was determined using sub-inhibitory concentrations of the fractions in association with antibiotics.

Results

The chemical analyzes revealed the presence of catechin, caffeic acid, rutin, orientin, quercetin, apigenin, luteolin and kaempferol, where all are present in the ethyl acetate fraction. The fractions exhibited moderate antioxidant and antimicrobial activities against Gram-positive and Candida strains in addition to modulating the activity of conventional antibiotics. The most expressive result was obtained from the association of the chloroform fraction with cefotaxime, which produced a synergistic effect, reducing the minimum inhibitory concentration (MIC) of the antibiotic from 1,024 to 256 μg/mL.

Discussion

The fractions presented a constitution rich in phenolic compounds, especially flavonoids. The data obtained demonstrated that the fractions presented moderate antioxidant activity by acting both as primary and secondary antioxidants. The fractions presented antimicrobial and antibiotic potentiating activities, being the first record of modulating effect of fractions of this species against the studied microbial strains, but failed in modulating the activity of antifungal drugs, indicating that this plant has the potential to be used in the development of therapeutic alternatives against resistant bacteria. The constitution phenolic the fractions may be responsible for their pharmacological properties in vitro.

Phytochemical Profile, Antioxidant and Antidiabetic Activities of Adansonia digitata L. (Baobab) from Mali, as a Source of Health-Promoting Compounds

Background: Adansonia digitata L. (Malvaceae), also known as baobab, is a tree attracting recent interest especially due to the high nutritional value of the fruit pulp. However, few studies are reported on the secondary metabolite content, showing high variability depending on the geographic region. Methods: In this study, the chemical profiles of Malian commercial baobab fruits and leaves, focused on phenolic content, were investigated by HPLC coupled with a photodiode array (PDA)/UV and an electrospray ionization (ESI) mass spectrometer (MS) and gas chromatography (GC)/MS. In addition, the extracts of fruit pulps obtained from three different markets (Fruits 1, 2, and 3) were evaluated for their total phenolic content (TPC), antioxidant activity and α-glucosidase inhibition. Results: Baobab fruit pulps were found to be rich in procyanidins and flavonol glycosides, with tiliroside as the major constituent. The baobab leaves showed a similar profile respect to the fruits, but with more detected phenolics. All fruit pulp extracts exerted antioxidant activity (highest for Fruit 3) and higher α-glucosidase inhibition than acarbose used as standard. Conclusions: This study confirmed the variability of baobab with different origins and indicated Malian species baobab as a promising source of health-promoting substances.

Antioxidant content and activity in leaves and petioles of six sweet potato (Ipomoea batatas L.) and antioxidant properties of blanched leaves

This study was conducted to compare antioxidant contents and antioxidative activities in the leaves and petioles of six sweet potato varieties, namely Danjami, Hayanmi, Hogammi, Jinyulmi, Poongwonmi, and Yeonjami. Total amount of phenolic acids was highest in Poongwonmi and lowest in Hogammi, while vitamin C level was highest in Danjami. Of four phenolic acids quantified, 3,5-dicaffeoylquinic acid was the most abundant in all varieties. The contents of phenolic acids and vitamin C were more than ten-fold higher in the leaves compared with the petioles. In addition, the leaves had much lower EC₅₀ values for DPPH scavenging activities and reducing power than the petioles, indicating that sweet potato leaves have a higher antioxidant capacity than the petioles. Blanching, including conventional and microwave, resulted in a considerable decrease of antioxidant content and activity in the leaves due to thermal degradation and leaching.

Effect of cooking treatments on the phytochemical composition and antidiabetic potential of Vernonia amygdalina

The present study aimed at evaluating the effects of domestic culinary treatment on phytochemical contents (phenolic content and dietary fiber), and the antidiabetic potential of Vernonia amygdalina in type 2 diabetic rats. The culinary forms implied boiling leaves of V. amygdalina directly and eliminating the leaves' bitterness before boiling. Seventy wistar rats were artificially induced with type 2 diabetes using streptozotocin and high-fat diet. They then received by oral intubation powders of different culinary forms of leaves extract or suspensions of V. amygdalina at a dose of 500 mg /kg for a period of 4 weeks. The crude fiber, total phenol contents and the DPPH scavenging ability of these culinary forms were also measured and the results showed that values of these parameters were higher in the unwashed form than the washed form. The washed and unwashed forms of V. amygdalina significantly reduced (p < 0.05) the blood glucose, the total cholesterol, triglyceride, transaminases, urea and creatine levels. Aqueous extract has the highest ability to reduce the blood glucose level (75.76%) followed by the unwashed form (61.17%) which was greater than that of the washed form. Also, these forms significantly increased serum HDL cholesterol and total protein level, with the highest activity obtained with the unwashed form. Washing the V. amygdalina leaves (that consists of multiple trituration of leaves with water) contributes to the reduction of antidiabetic and antioxidant properties.